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Papers by Elizabeth Davis

Science Education, 2008

Curriculum materials are a crucial tool with which teachers engage in teaching practice. For pres... more Curriculum materials are a crucial tool with which teachers engage in teaching practice. For preservice teachers to learn to use science curriculum materials in productive ways, they must develop a conception of themselves as elementary teachers in which the use of science curriculum materials is a valued dimension of science-teaching practice. We define those dimensions of teachers' professional role identities concerned with the use of curriculum materials as curricular role identity. This mixed-methods study examines preservice elementary teachers' development of curricular role identity for science teaching through their use of science curriculum materials. Forty-seven preservice elementary teachers in two sections of an elementary science methods course were studied over the course of one semester. Data sources include survey results from preservice teachers in both

Journal of Cataract & Refractive Surgery, 2000

To determine whether differences exist in visual acuity and corneal thickness after phacoemulsifi... more To determine whether differences exist in visual acuity and corneal thickness after phacoemulsification using various viscoelastic substances. Phillips Eye Institute, Minneapolis, Minnesota, USA. Fifty patients having routine phacoemulsification cataract extraction and intraocular lens implantation by a single surgeon using the same technique were randomly assigned to receive intraoperative administration of 1 of 3 viscoelastic substances: Amvisc Plus(R) (sodium hyaluronate 1.6%), OcuCoat(R) (hydroxypropyl methylcellulose 2%), or Viscoat(R) (chondroitin sulfate 4%-sodium hyaluronate 3%). Visual acuity and corneal thickness on the first postoperative day were compared between groups. Patients with a best corrected visual acuity (BCVA) of 20/40 or better 1 day postoperatively had significantly thinner corneas (596 microm) than those with a BCVA worse than 20/40 (639 microm). There were no differences in postoperative BCVA or percentage increase in central corneal pachymetry among the 3 viscoelastic groups. Viscoat, Amvisc Plus, and OcuCoat were comparable in their ability to produce clear corneas and good vision after routine phacoemulsification.

Diabetes Care, 1999

RESEARCH DESIGN AND METHODS — A total of eight centers with population-based childhood-onset diab... more RESEARCH DESIGN AND METHODS — A total of eight centers with population-based childhood-onset diabetes registers developed according to the standards of EURODIAB ACE (Aetiol-ogy of Childhood Onset Diabetes on an Epidemiological Basis) (18) part icipated ...

Flowering at the appropriate time of year is essential for successful reproduction in plants. We ... more Flowering at the appropriate time of year is essential for successful reproduction in plants. We found that HAP3b in Arabidopsis (Arabidopsis thaliana), a putative CCAAT-binding transcription factor gene, is involved in controlling flowering time. Overexpression of HAP3b promotes early flowering while hap3b, a null mutant of HAP3b, is delayed in flowering under a long-day photoperiod. Under short-day conditions, however, hap3b did not show a delayed flowering compared to wild type based on the leaf number, suggesting that HAP3b may normally be involved in the photoperiod-regulated flowering pathway. Mutant hap3b plants showed earlier flowering upon gibberellic acid or vernalization treatment, which means that HAP3b is not involved in flowering promoted by gibberellin or vernalization. Further transcript profiling and gene expression analysis suggests that HAP3b can promote flowering by enhancing expression of key flowering time genes such as FLOWERING LOCUS T and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1. Our results provide strong evidence supporting a role of HAP3b in regulating flowering in plants grown under long-day conditions.

The American Journal of Cardiology, 2006

The aim of this study was to investigate the impact of obesity on diastolic function in children ... more The aim of this study was to investigate the impact of obesity on diastolic function in children and adolescents. Echocardiographic measurements were compared in 28 obese subjects (14 males, 14 females) and 15 age- and gender-matched lean controls (8 males, 7 females). Two-dimensional ultrasound imaging, M-mode imaging, and pulse-wave conventional and tissue Doppler measurements were used to assess cardiac structure and function at rest. No differences were evident between lean and obese subjects in age (13.3 +/- 0.5 vs 12.4 +/- 0.4 years), height (163 +/- 4 vs 159 +/- 2 cm), or systolic blood pressure (119 +/- 3 vs 123 +/- 2 mm Hg). Body mass (54.6 +/- 4.0 vs 85.8 +/- 3.6 kg, p < 0.0001) and body mass index (20.5 +/- 0.7 vs 33.3 +/- 1.0 kg/m2, p < 0.00001) were significantly greater in the obese subjects, whereas measurements of wall thickness (interventricular septal wall 0.86 +/- 0.04 vs 0.89 +/- 0.02 cm, posterior wall 0.83 +/- 0.04 vs 0.91 +/- 0.02 cm) and fractional shortening (38.6 +/- 1.2% vs 38.8 +/- 1.2%) did not significantly differ. The E/E' ratio (6.86 +/- 0.20 vs 8.30 +/- 0.32, p…

Edad de Oro Cantabrigense: Actas del VII Congreso de la Asociación Internacional del Siglo de Oro (AISO). Anthony Close, ed. Madrid: Iberoamericana Editorial Vervuert, 2006

Context: The number of obese children with insulin resistance and type 2 diabetes is increasing, ... more Context: The number of obese children with insulin resistance and type 2 diabetes is increasing, but the best management strategy is not clear. Objective: The objective of this study was to assess the effect of a structured 8-wk exercise training program on insulin resistance and changes in body composition in obese children. Design: The study was 8 wk of structured supervised exercise intervention with outcome measures before and after the exercise period. Subjects: Fourteen obese children (12.70 Ϯ 2.32 yr; eight male, six female) with high fasting insulin levels were enrolled into the study. Intervention: Intervention consisted of 8 wk of supervised circuitbased exercise training, composed of three fully supervised 1-h sessions per week. Outcome Measures: Outcome measures were assessed pretraining program and posttraining program and included insulin sensitivity (euglycemic-hyperinsulinemic clamp studies), fasting insulin and glucose levels, body composition using dual energy x-ray absorptiometry scan, lipid profile, and liver function tests. Results: Insulin sensitivity improved significantly after 8 wk of training (M lbm 8.20 Ϯ 3.44 to 10.03 Ϯ 4.33 mg/kg⅐min, P Ͻ 0.05). Submaximal exercise heart rate responses were significantly lower following the training (P Ͻ 0.05), indicating an improvement in cardiorespiratory fitness. Dual energy x-ray absorptiometry scans revealed no differences in lean body mass or abdominal fat mass. Conclusion: An 8-wk exercise training program increases insulin sensitivity in obese children, and this improvement occurred in the presence of increased cardiorespiratory fitness but is independent of measurable changes in body composition.

Context: Overweight/obesity in children is increasing. Incidence data for medical complications u... more Context: Overweight/obesity in children is increasing. Incidence data for medical complications use arbitrary cutoff values for categories of overweight and obesity. Continuous relationships are seldom reported. Objectives: The objective of this study is to report relationships of child body mass index (BMI) z-score as a continuous variable with the medical complications of overweight. Design: This study is a part of the larger, prospective cohort Growth and Development Study. Setting: Children were recruited from the community through randomly selected primary schools. Overweight children seeking treatment were recruited through tertiary centers. Participants: Children aged 6-13 yr were community-recruited normal weight (n ϭ 73), community-recruited overweight (n ϭ 53), and overweight treatment-seeking (n ϭ 51). Medical history, family history, and symptoms of complications of overweight were collected by interview, and physical examination was performed. Investigations included oral glucose tolerance tests, fasting lipids, and liver function tests. Main Outcome Measure: Adjusted regression was used to model each complication of obesity with age-and sex-specific child BMI z-scores entered as a continuous dependent variable. Results: Adjusted logistic regression showed the proportion of children with musculoskeletal pain, obstructive sleep apnea symptoms, headaches, depression, anxiety, bullying, and acanthosis nigricans increased with child BMI z-score. Adjusted linear regression showed BMI z-score was significantly related to systolic and diastolic blood pressure, insulin during oral glucose tolerance test, total cholesterol, high-density lipoprotein, triglycerides, and alanine aminotransferase. Conclusion: Child's BMI z-score is independently related to complications of overweight and obesity in a linear or curvilinear fashion. Children's risks of most complications increase across the entire range of BMI values and are not defined by thresholds.

AIDS Care, 2007

The objective is to assess patient preferences for attributes associated with third agent HIV med... more The objective is to assess patient preferences for attributes associated with third agent HIV medications, including fosamprenavir/ritonavir (FPVr), fosamprenavir (FPV), lopinavir/ritonavir (LPVr), atazanavir (ATZ), and efavirenz (EFV). Subjects with HIV were recruited in the US and Germany to complete a computerized adaptive conjoint survey that assessed 13 attributes, including moderate to severe side effects, regimen convenience, drug resistance and efficacy. Literature on the target third-agent HIV drugs was used to identify percentage risk and severity level descriptions for each attribute. The derived preference (utility) weights for each attribute level informed the calculation of relative importance estimates for each attribute and the desirability of combinations of attributes matching the respective target third agents. The analysis included 288 HIV-positive participants (US: 132; Germany: 156), 205 of whom were treatment-experienced and 83 of whom were treatment-naïve. Of the 13 medication attributes evaluated, developing drug resistance, the risk of lipodystrophy, the risk of gastronitestinal side effects (diarrhoea, nausea and vomiting) and regimen convenience had the greatest impact on preferences. The profile based on FPVr was most preferred. Differences in the risk of developing drug resistance, risk of lipodystrophy, risk of gastrointestinal side effects and regimen convenience would likely be most influential in the perceived relative value of a third-agent medication. Physicians may wish to consider these features, especially when discussing HIV treatment options with their patients.

AIDS Care, 2008

Research on HIV medication adherence has relied mainly on quantitative methods. The objective of ... more Research on HIV medication adherence has relied mainly on quantitative methods. The objective of this study was to explore factors associated with adherence from the HIV-infected patient's perspective. Six focus groups were convened with treatment-experienced HIV-positive individuals. The discussions focused on issues that make it easy or difficult to adhere to HIV regimens. Thirty-five patients participated in the focus groups, which were conducted in Washington, D.C., and Los Angeles. The mean age was 48; 66% were male; 63% were black; and 40% contracted HIV through heterosexual contact. Six major themes emerged from the data that influenced adherence to medication: regimen complexity/medication features (including number of pills), lifestyle fit, emotional impacts (including worry, anger, stress and anxiety), side effects, medication effectiveness, and communication (including information from friends, physicians, and published sources). The data informed a conceptual framework, illustrating the possible interactions among these themes that can potentially be used by clinicians when discussing HIV treatment options with patients. This is potentially one of the first focus group studies concentrating on HIV medication adherence. The findings highlight specific factors that should be considered when trying to improve adherence and may be helpful in clinical decision-making.

AIDS Care, 2008

This study sought to identify how urban gay communities are undergoing structural change, reasons... more This study sought to identify how urban gay communities are undergoing structural change, reasons for that change, and implications for HIV prevention planning. Key informants (N=29) at the AIDS Impact Conference from 17 cities in 14 countries completed surveys and participated in a facilitated structured dialog about how gay communities are changing. In all cities, the virtual gay community was identified as now larger than the offline physical community. Most cities identified that while the gay population in their cities appeared stable or growing, the gay community appeared in decline. Measures included greater integration of heterosexuals into historically gay-identified neighborhoods and movement of gay persons into suburbs, decreased number of gay bars and clubs, less attendance at gay events, less volunteerism in gay or AIDS organizations and overall identification and visibility as a gay community. Participants attributed structural change to multiple factors including gay neighborhood gentrification, achievement of civil rights, less discrimination, a vibrant virtual community and changes in drug use. Consistent with social assimilation, across cities, gay infrastructure, visibility and community identification appears to be decreasing. HIV prevention planning, interventions, treatment services, and policies need to be re-conceptualized for MSM in post-gay communities. Four recommendations for future HIV prevention and research are detailed.

AIDS and Behavior, 2011

Adolescents who abuse substances are more likely to engage in health-risking sexual behavior (HRS... more Adolescents who abuse substances are more likely to engage in health-risking sexual behavior (HRSB) and are at particularly high risk for HIV/AIDS. Thus, substance abuse treatment presents a prime opportunity to target HIV-risk behaviors. The present study evaluated a one-session HIV-risk intervention embedded in a controlled clinical trial for drug-abusing adolescents. The trial was conducted in New Mexico and Oregon with Hispanic and Anglo adolescents. Youths were randomly assigned to individual cognitive behavior therapy (CBT) or to an integrated behavioral and family therapy (IBFT) condition, involving individual and family sessions. The HIV-specific intervention was not associated with change. IBFT and CBT were both efficacious in reducing HIV-risk behaviors from intake to the 18-month follow-up for high-risk adolescents. For low-risk adolescents, CBT (versus IBFT) was more efficacious in suppressing HRSB. These data suggest that drug abuse treatments can have both preventative and intervention effects for adolescents, depending on their relative HIV-risk.

Pharmacotherapy, 2002

This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NH... more This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. Health technology The health technology was controller therapy for patients with asthma. The comparators were inhaled corticosteroids and leukotriene modifiers in real world clinical practice. The authors compared fluticasone propionate (44 or 110 microg) with oral zafirlukast (20 mg) and montelukast (5 or 10 mg). Type of intervention Primary prevention. Economic study type Cost-effectiveness analysis. Study population The study population included patients that had a primary ICD-9-CM code (493.xxx) for asthma that occurred any time in the database. The patients were aged 4 years or older and had to have been enrolled in the plan continuously for at least 18 months, that is, 9 months before (preindex) and 9 months after (postindex) the first initial prescription. During the initial 9 months, the patients were required not to have had an inhaled corticosteroid or an oral leukotriene modifier. Patients were excluded if they had pharmacy claims for several drugs of interest, they were younger than 4 years or older than 45 years, and if they had had one or more prescriptions for ipratropium bromide during the study period. Patients with a diagnosis of cystic fibrosis or chronic obstructive pulmonary disease were also excluded. Setting The setting was secondary care. The economic study was carried out in the USA. Dates to which data relate The effectiveness data were collected from 1 July 1997 to 30 June 1999. The dates to which the costs referred were unclear, although they appear to have been the same as those for the effectiveness data. The price year was not reported. Source of effectiveness data The effectiveness data were derived from a single study. Link between effectiveness and cost data It was not stated clearly whether the costing was undertaken on the same sample as that used in the effectiveness study. However, it appears that the costing has been undertaken retrospectively on the same sample.

The Annals of pharmacotherapy, 2001

To provide a comparative evaluation of psychometric properties for three or more HIV disease-spec... more To provide a comparative evaluation of psychometric properties for three or more HIV disease-specific quality-of-life (QoL) instruments. Four instruments were selected using the following criteria: multiple publiations of instrument, focus of instrument on QoL, psychometric validation publication or comparison with prevoiusly validated questionnaire, stages of HIV/AIDS used or evaluated in the study, and inclusion of sample items or the instrument in at least one publication. The four HIV-specific QoL instruments were: HIV/AIDS-Targeted Quality of Life Instrument, Medical Outcomes Study HIV questionnaire (MOS-HIV), Functional Assessment of Human Immunodeficiency Virus Infection, and HIV Overview of Problems -- Evaluation System. These instruments were evaluated using combined criteria derived from McHorney and Tarlov and Shumaker et al. The criteria include: administration, content, depth, reliability, validity, and responsiveness. A letter grade scale (A,B,C,D) was used in rating the criteria. No instrument demonstrated ideal psychometric properties. The MOS-HIV questionnaire was the only instrument that published results for seven of the eight categories. Therefore, a decision cannot be made about the best instrument to use for measuring QoL in an HIV-positive patient. Published data for these questionnaires had common limitations of sample size, study design, and population demograhpics, Hence, further testing of these questionnaires is recommended before use in any study to determine suitability, reliability and validity.

The microtubule-severing enzyme katanin uses ATP hydrolysis to disrupt noncovalent bonds between ... more The microtubule-severing enzyme katanin uses ATP hydrolysis to disrupt noncovalent bonds between tubulin dimers within the microtubule lattice. Although its microtubule severing activity is likely important for fundamental processes including mitosis and axonal outgrowth, its mechanism of action is poorly understood. To better understand this activity, an in vitro assay was developed to enable the real-time observation of katanin-mediated severing of individual, mechanically unconstrained microtubules. To interpret the experimental observations, a number of theoretical models were developed and compared quantitatively to the experimental data via Monte Carlo simulation. Models that assumed that katanin acts on a uniform microtubule lattice were incompatible with the in vitro data, whereas a model that assumed that katanin acts preferentially on spatially infrequent microtubule lattice defects was found to correctly predict the experimentally observed breaking rates, number and spatial frequency of severing events, final levels of severing, and sensitivity to katanin concentration over the range 6-300 nM. As a result of our analysis, we propose that defects in the microtubule lattice, which are known to exist but previously not known to have any biological function, serve as sites for katanin activity.

The Journal of …, 2004

Objectives Atherosclerosis is a disease that begins in childhood; endothelial dysfunction is its ... more Objectives Atherosclerosis is a disease that begins in childhood; endothelial dysfunction is its earliest detectable manifestation, and primary prevention strategies are likely to be most effective if instituted early. The aim of this study was to characterize the impact of obesity on vascular function in young children and to determine whether an exercise program improves abnormalities in vascular function. Study design The influence of 8 weeks of exercise training was examined in 14 obese subjects, 8.9 ± 0.4 years of age, with the use of a randomized crossover protocol. Conduit vessel endothelial function was assessed by means of high-resolution ultrasound and flow-mediated dilation of the brachial artery (FMD). Results Exercise training did not change subcutaneous fat mass, body weight, or body mass index. FMD in the obese group was significantly impaired relative to matched control subjects at entry (6.00% ± 0.69% to 12.32% ± 3.14%, P < .0001). FMD significantly improved with exercise training (7.35% ± 0.99%, P < .05) in the obese group. Conclusions Conduit vessel FMD, a validated surrogate measure of early atherosclerosis, was impaired in obese children but improved as a result of exercise training. This study supports the value of an exercise program in the treatment of obese children in a primary prevention setting.

Journal of the American …, 2004

We sought to characterize the impact of obesity on vascular function in adolescents and to determ... more We sought to characterize the impact of obesity on vascular function in adolescents and to determine whether an exercise program reverses abnormalities in endothelial function. BACKGROUND Obesity, a major modifiable risk factor for cardiovascular disease, is epidemic in Western societies, with rapid rates of increase in the young. Atherosclerosis begins in childhood, and endothelial dysfunction is its earliest detectable manifestation. METHODS The influence of eight weeks of circuit training (CT) was examined in 19 obese subjects (14.3 Ϯ 1.5 years), using a randomized, crossover protocol. Functional capacity and muscular strength were assessed by standard techniques. Body composition was examined using anthropometric measures and dual-energy X-ray absorptiometry. Conduit vessel endothelial function was assessed using high-resolution ultrasound and flow-mediated dilation (FMD) of the brachial artery. RESULTS Circuit training decreased abdominal and trunk fat and significantly improved fitness and muscular strength (p Ͻ 0.05). In the obese group, FMD was significantly impaired relative to control subjects (n ϭ 20) at entry (5.3 Ϯ 0.9% vs. 8.9 Ϯ 1.5%, p Ͻ 0.05) and was normalized after CT (8.8 Ϯ 0.8%, p Ͻ 0.05). CONCLUSIONS Circuit training improved functional capacity, muscular strength, and body composition in obese adolescents. Furthermore, conduit vessel function was normalized after exercise training. If vascular dysfunction is an integral component of the pathogenesis of vascular disease, this study supports the value of an exercise program in the management of obese adolescents.

Journal of Bone …, 2008

Vitamin D insufficiency (VDI) is widely reported. In patients with normal PTH, the diagnosis rest... more Vitamin D insufficiency (VDI) is widely reported. In patients with normal PTH, the diagnosis rests on increases in fractional calcium absorption (FCA) when 25(OH)D increases above 30 ng/ml. However, estimates of increased FCA after correction of VDI vary dramatically, depending on study methods. We used a dual stable calcium isotope to clarify the impact of vitamin D repletion on FCA in postmenopausal women with VDI. We hypothesized that FCA would increase with vitamin D repletion. We studied postmenopausal women with VDI [25(OH)D ‫ס‬ 16-24 ng/ml] and an estimated calcium intake Յ1100 mg daily. Exclusion criteria included hypercalcemia, hypercalciuria, renal insufficiency, nephrolithiasis, gastrointestinal disorders, osteomalacia, prior adult fragility fracture, baseline T-score < −3.0, and use of medications known to interfere with vitamin D or calcium metabolism. Each woman underwent inpatient FCA studies before and after correction of VDI. We used ergocalciferol 50,000 IU/d for 15 days to achieve vitamin D repletion. During each study, women consumed their typical diet. They ingested 44 Ca orally with breakfast and received 42 Ca intravenously. We collected urine for 24 h and measured its calcium isotope content by mass spectrometry. Eighteen women completed the study; all but two had normal PTH. During the first and second FCA studies, their mean 25(OH)D level was 22 ± 4 and 64 ± 21 ng/ml, respectively (p < 0.001). Subjects' average FCA was 24 ± 7% initially and 27 ± 6% after vitamin D repletion (p ‫ס‬ 0.04). Thus, FCA increased by 3 ± 1% with correction of VDI. Postmenopausal women with VDI experience small FCA increments with vitamin D therapy. In existing literature, this small change in FCA does not associate with lower fracture rates or consistently higher bone mass. Future studies should ascertain whether small FCA increments favorably affect the skeleton.

Association for Science Teacher Education, St. Louis, MO, 2008

Scientific modeling is a crucial scientific practice, yet it is rarely incorporated into elementa... more Scientific modeling is a crucial scientific practice, yet it is rarely incorporated into elementary and middle school classrooms. Teachers typically have limited knowledge of models and modeling or of students' ideas about models and modeling. Yet engaging in scientific modeling in the classroom places a high demand on teachers, and they typically do not have access to highquality modeling-oriented curriculum materials. The MoDeLS project works to design innovative and effective supports for teachers' learning around ...

Journal of Research in Science Teaching, Aug 1, 2009

Modeling is a core practice in science and a central part of scientific literacy. We present theo... more Modeling is a core practice in science and a central part of scientific literacy. We present theoretical and empirical motivation for a learning progression for scientific modeling that aims to make the practice accessible and meaningful for learners. We define scientific modeling as including the elements of the practice (constructing, using, evaluating, and revising scientific models) and the metaknowledge that guides and motivates the practice (eg, understanding the nature and purpose of models). Our learning progression ...

Science Education, 2008

Curriculum materials are a crucial tool with which teachers engage in teaching practice. For pres... more Curriculum materials are a crucial tool with which teachers engage in teaching practice. For preservice teachers to learn to use science curriculum materials in productive ways, they must develop a conception of themselves as elementary teachers in which the use of science curriculum materials is a valued dimension of science-teaching practice. We define those dimensions of teachers' professional role identities concerned with the use of curriculum materials as curricular role identity. This mixed-methods study examines preservice elementary teachers' development of curricular role identity for science teaching through their use of science curriculum materials. Forty-seven preservice elementary teachers in two sections of an elementary science methods course were studied over the course of one semester. Data sources include survey results from preservice teachers in both

Journal of Cataract & Refractive Surgery, 2000

To determine whether differences exist in visual acuity and corneal thickness after phacoemulsifi... more To determine whether differences exist in visual acuity and corneal thickness after phacoemulsification using various viscoelastic substances. Phillips Eye Institute, Minneapolis, Minnesota, USA. Fifty patients having routine phacoemulsification cataract extraction and intraocular lens implantation by a single surgeon using the same technique were randomly assigned to receive intraoperative administration of 1 of 3 viscoelastic substances: Amvisc Plus(R) (sodium hyaluronate 1.6%), OcuCoat(R) (hydroxypropyl methylcellulose 2%), or Viscoat(R) (chondroitin sulfate 4%-sodium hyaluronate 3%). Visual acuity and corneal thickness on the first postoperative day were compared between groups. Patients with a best corrected visual acuity (BCVA) of 20/40 or better 1 day postoperatively had significantly thinner corneas (596 microm) than those with a BCVA worse than 20/40 (639 microm). There were no differences in postoperative BCVA or percentage increase in central corneal pachymetry among the 3 viscoelastic groups. Viscoat, Amvisc Plus, and OcuCoat were comparable in their ability to produce clear corneas and good vision after routine phacoemulsification.

Diabetes Care, 1999

RESEARCH DESIGN AND METHODS — A total of eight centers with population-based childhood-onset diab... more RESEARCH DESIGN AND METHODS — A total of eight centers with population-based childhood-onset diabetes registers developed according to the standards of EURODIAB ACE (Aetiol-ogy of Childhood Onset Diabetes on an Epidemiological Basis) (18) part icipated ...

Flowering at the appropriate time of year is essential for successful reproduction in plants. We ... more Flowering at the appropriate time of year is essential for successful reproduction in plants. We found that HAP3b in Arabidopsis (Arabidopsis thaliana), a putative CCAAT-binding transcription factor gene, is involved in controlling flowering time. Overexpression of HAP3b promotes early flowering while hap3b, a null mutant of HAP3b, is delayed in flowering under a long-day photoperiod. Under short-day conditions, however, hap3b did not show a delayed flowering compared to wild type based on the leaf number, suggesting that HAP3b may normally be involved in the photoperiod-regulated flowering pathway. Mutant hap3b plants showed earlier flowering upon gibberellic acid or vernalization treatment, which means that HAP3b is not involved in flowering promoted by gibberellin or vernalization. Further transcript profiling and gene expression analysis suggests that HAP3b can promote flowering by enhancing expression of key flowering time genes such as FLOWERING LOCUS T and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1. Our results provide strong evidence supporting a role of HAP3b in regulating flowering in plants grown under long-day conditions.

The American Journal of Cardiology, 2006

The aim of this study was to investigate the impact of obesity on diastolic function in children ... more The aim of this study was to investigate the impact of obesity on diastolic function in children and adolescents. Echocardiographic measurements were compared in 28 obese subjects (14 males, 14 females) and 15 age- and gender-matched lean controls (8 males, 7 females). Two-dimensional ultrasound imaging, M-mode imaging, and pulse-wave conventional and tissue Doppler measurements were used to assess cardiac structure and function at rest. No differences were evident between lean and obese subjects in age (13.3 +/- 0.5 vs 12.4 +/- 0.4 years), height (163 +/- 4 vs 159 +/- 2 cm), or systolic blood pressure (119 +/- 3 vs 123 +/- 2 mm Hg). Body mass (54.6 +/- 4.0 vs 85.8 +/- 3.6 kg, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001) and body mass index (20.5 +/- 0.7 vs 33.3 +/- 1.0 kg/m2, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.00001) were significantly greater in the obese subjects, whereas measurements of wall thickness (interventricular septal wall 0.86 +/- 0.04 vs 0.89 +/- 0.02 cm, posterior wall 0.83 +/- 0.04 vs 0.91 +/- 0.02 cm) and fractional shortening (38.6 +/- 1.2% vs 38.8 +/- 1.2%) did not significantly differ. The E/E&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; ratio (6.86 +/- 0.20 vs 8.30 +/- 0.32, p…

Edad de Oro Cantabrigense: Actas del VII Congreso de la Asociación Internacional del Siglo de Oro (AISO). Anthony Close, ed. Madrid: Iberoamericana Editorial Vervuert, 2006

Context: The number of obese children with insulin resistance and type 2 diabetes is increasing, ... more Context: The number of obese children with insulin resistance and type 2 diabetes is increasing, but the best management strategy is not clear. Objective: The objective of this study was to assess the effect of a structured 8-wk exercise training program on insulin resistance and changes in body composition in obese children. Design: The study was 8 wk of structured supervised exercise intervention with outcome measures before and after the exercise period. Subjects: Fourteen obese children (12.70 Ϯ 2.32 yr; eight male, six female) with high fasting insulin levels were enrolled into the study. Intervention: Intervention consisted of 8 wk of supervised circuitbased exercise training, composed of three fully supervised 1-h sessions per week. Outcome Measures: Outcome measures were assessed pretraining program and posttraining program and included insulin sensitivity (euglycemic-hyperinsulinemic clamp studies), fasting insulin and glucose levels, body composition using dual energy x-ray absorptiometry scan, lipid profile, and liver function tests. Results: Insulin sensitivity improved significantly after 8 wk of training (M lbm 8.20 Ϯ 3.44 to 10.03 Ϯ 4.33 mg/kg⅐min, P Ͻ 0.05). Submaximal exercise heart rate responses were significantly lower following the training (P Ͻ 0.05), indicating an improvement in cardiorespiratory fitness. Dual energy x-ray absorptiometry scans revealed no differences in lean body mass or abdominal fat mass. Conclusion: An 8-wk exercise training program increases insulin sensitivity in obese children, and this improvement occurred in the presence of increased cardiorespiratory fitness but is independent of measurable changes in body composition.

Context: Overweight/obesity in children is increasing. Incidence data for medical complications u... more Context: Overweight/obesity in children is increasing. Incidence data for medical complications use arbitrary cutoff values for categories of overweight and obesity. Continuous relationships are seldom reported. Objectives: The objective of this study is to report relationships of child body mass index (BMI) z-score as a continuous variable with the medical complications of overweight. Design: This study is a part of the larger, prospective cohort Growth and Development Study. Setting: Children were recruited from the community through randomly selected primary schools. Overweight children seeking treatment were recruited through tertiary centers. Participants: Children aged 6-13 yr were community-recruited normal weight (n ϭ 73), community-recruited overweight (n ϭ 53), and overweight treatment-seeking (n ϭ 51). Medical history, family history, and symptoms of complications of overweight were collected by interview, and physical examination was performed. Investigations included oral glucose tolerance tests, fasting lipids, and liver function tests. Main Outcome Measure: Adjusted regression was used to model each complication of obesity with age-and sex-specific child BMI z-scores entered as a continuous dependent variable. Results: Adjusted logistic regression showed the proportion of children with musculoskeletal pain, obstructive sleep apnea symptoms, headaches, depression, anxiety, bullying, and acanthosis nigricans increased with child BMI z-score. Adjusted linear regression showed BMI z-score was significantly related to systolic and diastolic blood pressure, insulin during oral glucose tolerance test, total cholesterol, high-density lipoprotein, triglycerides, and alanine aminotransferase. Conclusion: Child's BMI z-score is independently related to complications of overweight and obesity in a linear or curvilinear fashion. Children's risks of most complications increase across the entire range of BMI values and are not defined by thresholds.

AIDS Care, 2007

The objective is to assess patient preferences for attributes associated with third agent HIV med... more The objective is to assess patient preferences for attributes associated with third agent HIV medications, including fosamprenavir/ritonavir (FPVr), fosamprenavir (FPV), lopinavir/ritonavir (LPVr), atazanavir (ATZ), and efavirenz (EFV). Subjects with HIV were recruited in the US and Germany to complete a computerized adaptive conjoint survey that assessed 13 attributes, including moderate to severe side effects, regimen convenience, drug resistance and efficacy. Literature on the target third-agent HIV drugs was used to identify percentage risk and severity level descriptions for each attribute. The derived preference (utility) weights for each attribute level informed the calculation of relative importance estimates for each attribute and the desirability of combinations of attributes matching the respective target third agents. The analysis included 288 HIV-positive participants (US: 132; Germany: 156), 205 of whom were treatment-experienced and 83 of whom were treatment-naïve. Of the 13 medication attributes evaluated, developing drug resistance, the risk of lipodystrophy, the risk of gastronitestinal side effects (diarrhoea, nausea and vomiting) and regimen convenience had the greatest impact on preferences. The profile based on FPVr was most preferred. Differences in the risk of developing drug resistance, risk of lipodystrophy, risk of gastrointestinal side effects and regimen convenience would likely be most influential in the perceived relative value of a third-agent medication. Physicians may wish to consider these features, especially when discussing HIV treatment options with their patients.

AIDS Care, 2008

Research on HIV medication adherence has relied mainly on quantitative methods. The objective of ... more Research on HIV medication adherence has relied mainly on quantitative methods. The objective of this study was to explore factors associated with adherence from the HIV-infected patient&amp;amp;#39;s perspective. Six focus groups were convened with treatment-experienced HIV-positive individuals. The discussions focused on issues that make it easy or difficult to adhere to HIV regimens. Thirty-five patients participated in the focus groups, which were conducted in Washington, D.C., and Los Angeles. The mean age was 48; 66% were male; 63% were black; and 40% contracted HIV through heterosexual contact. Six major themes emerged from the data that influenced adherence to medication: regimen complexity/medication features (including number of pills), lifestyle fit, emotional impacts (including worry, anger, stress and anxiety), side effects, medication effectiveness, and communication (including information from friends, physicians, and published sources). The data informed a conceptual framework, illustrating the possible interactions among these themes that can potentially be used by clinicians when discussing HIV treatment options with patients. This is potentially one of the first focus group studies concentrating on HIV medication adherence. The findings highlight specific factors that should be considered when trying to improve adherence and may be helpful in clinical decision-making.

AIDS Care, 2008

This study sought to identify how urban gay communities are undergoing structural change, reasons... more This study sought to identify how urban gay communities are undergoing structural change, reasons for that change, and implications for HIV prevention planning. Key informants (N=29) at the AIDS Impact Conference from 17 cities in 14 countries completed surveys and participated in a facilitated structured dialog about how gay communities are changing. In all cities, the virtual gay community was identified as now larger than the offline physical community. Most cities identified that while the gay population in their cities appeared stable or growing, the gay community appeared in decline. Measures included greater integration of heterosexuals into historically gay-identified neighborhoods and movement of gay persons into suburbs, decreased number of gay bars and clubs, less attendance at gay events, less volunteerism in gay or AIDS organizations and overall identification and visibility as a gay community. Participants attributed structural change to multiple factors including gay neighborhood gentrification, achievement of civil rights, less discrimination, a vibrant virtual community and changes in drug use. Consistent with social assimilation, across cities, gay infrastructure, visibility and community identification appears to be decreasing. HIV prevention planning, interventions, treatment services, and policies need to be re-conceptualized for MSM in post-gay communities. Four recommendations for future HIV prevention and research are detailed.

AIDS and Behavior, 2011

Adolescents who abuse substances are more likely to engage in health-risking sexual behavior (HRS... more Adolescents who abuse substances are more likely to engage in health-risking sexual behavior (HRSB) and are at particularly high risk for HIV/AIDS. Thus, substance abuse treatment presents a prime opportunity to target HIV-risk behaviors. The present study evaluated a one-session HIV-risk intervention embedded in a controlled clinical trial for drug-abusing adolescents. The trial was conducted in New Mexico and Oregon with Hispanic and Anglo adolescents. Youths were randomly assigned to individual cognitive behavior therapy (CBT) or to an integrated behavioral and family therapy (IBFT) condition, involving individual and family sessions. The HIV-specific intervention was not associated with change. IBFT and CBT were both efficacious in reducing HIV-risk behaviors from intake to the 18-month follow-up for high-risk adolescents. For low-risk adolescents, CBT (versus IBFT) was more efficacious in suppressing HRSB. These data suggest that drug abuse treatments can have both preventative and intervention effects for adolescents, depending on their relative HIV-risk.

Pharmacotherapy, 2002

This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NH... more This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. Health technology The health technology was controller therapy for patients with asthma. The comparators were inhaled corticosteroids and leukotriene modifiers in real world clinical practice. The authors compared fluticasone propionate (44 or 110 microg) with oral zafirlukast (20 mg) and montelukast (5 or 10 mg). Type of intervention Primary prevention. Economic study type Cost-effectiveness analysis. Study population The study population included patients that had a primary ICD-9-CM code (493.xxx) for asthma that occurred any time in the database. The patients were aged 4 years or older and had to have been enrolled in the plan continuously for at least 18 months, that is, 9 months before (preindex) and 9 months after (postindex) the first initial prescription. During the initial 9 months, the patients were required not to have had an inhaled corticosteroid or an oral leukotriene modifier. Patients were excluded if they had pharmacy claims for several drugs of interest, they were younger than 4 years or older than 45 years, and if they had had one or more prescriptions for ipratropium bromide during the study period. Patients with a diagnosis of cystic fibrosis or chronic obstructive pulmonary disease were also excluded. Setting The setting was secondary care. The economic study was carried out in the USA. Dates to which data relate The effectiveness data were collected from 1 July 1997 to 30 June 1999. The dates to which the costs referred were unclear, although they appear to have been the same as those for the effectiveness data. The price year was not reported. Source of effectiveness data The effectiveness data were derived from a single study. Link between effectiveness and cost data It was not stated clearly whether the costing was undertaken on the same sample as that used in the effectiveness study. However, it appears that the costing has been undertaken retrospectively on the same sample.

The Annals of pharmacotherapy, 2001

To provide a comparative evaluation of psychometric properties for three or more HIV disease-spec... more To provide a comparative evaluation of psychometric properties for three or more HIV disease-specific quality-of-life (QoL) instruments. Four instruments were selected using the following criteria: multiple publiations of instrument, focus of instrument on QoL, psychometric validation publication or comparison with prevoiusly validated questionnaire, stages of HIV/AIDS used or evaluated in the study, and inclusion of sample items or the instrument in at least one publication. The four HIV-specific QoL instruments were: HIV/AIDS-Targeted Quality of Life Instrument, Medical Outcomes Study HIV questionnaire (MOS-HIV), Functional Assessment of Human Immunodeficiency Virus Infection, and HIV Overview of Problems -- Evaluation System. These instruments were evaluated using combined criteria derived from McHorney and Tarlov and Shumaker et al. The criteria include: administration, content, depth, reliability, validity, and responsiveness. A letter grade scale (A,B,C,D) was used in rating the criteria. No instrument demonstrated ideal psychometric properties. The MOS-HIV questionnaire was the only instrument that published results for seven of the eight categories. Therefore, a decision cannot be made about the best instrument to use for measuring QoL in an HIV-positive patient. Published data for these questionnaires had common limitations of sample size, study design, and population demograhpics, Hence, further testing of these questionnaires is recommended before use in any study to determine suitability, reliability and validity.

The microtubule-severing enzyme katanin uses ATP hydrolysis to disrupt noncovalent bonds between ... more The microtubule-severing enzyme katanin uses ATP hydrolysis to disrupt noncovalent bonds between tubulin dimers within the microtubule lattice. Although its microtubule severing activity is likely important for fundamental processes including mitosis and axonal outgrowth, its mechanism of action is poorly understood. To better understand this activity, an in vitro assay was developed to enable the real-time observation of katanin-mediated severing of individual, mechanically unconstrained microtubules. To interpret the experimental observations, a number of theoretical models were developed and compared quantitatively to the experimental data via Monte Carlo simulation. Models that assumed that katanin acts on a uniform microtubule lattice were incompatible with the in vitro data, whereas a model that assumed that katanin acts preferentially on spatially infrequent microtubule lattice defects was found to correctly predict the experimentally observed breaking rates, number and spatial frequency of severing events, final levels of severing, and sensitivity to katanin concentration over the range 6-300 nM. As a result of our analysis, we propose that defects in the microtubule lattice, which are known to exist but previously not known to have any biological function, serve as sites for katanin activity.

The Journal of …, 2004

Objectives Atherosclerosis is a disease that begins in childhood; endothelial dysfunction is its ... more Objectives Atherosclerosis is a disease that begins in childhood; endothelial dysfunction is its earliest detectable manifestation, and primary prevention strategies are likely to be most effective if instituted early. The aim of this study was to characterize the impact of obesity on vascular function in young children and to determine whether an exercise program improves abnormalities in vascular function. Study design The influence of 8 weeks of exercise training was examined in 14 obese subjects, 8.9 ± 0.4 years of age, with the use of a randomized crossover protocol. Conduit vessel endothelial function was assessed by means of high-resolution ultrasound and flow-mediated dilation of the brachial artery (FMD). Results Exercise training did not change subcutaneous fat mass, body weight, or body mass index. FMD in the obese group was significantly impaired relative to matched control subjects at entry (6.00% ± 0.69% to 12.32% ± 3.14%, P < .0001). FMD significantly improved with exercise training (7.35% ± 0.99%, P < .05) in the obese group. Conclusions Conduit vessel FMD, a validated surrogate measure of early atherosclerosis, was impaired in obese children but improved as a result of exercise training. This study supports the value of an exercise program in the treatment of obese children in a primary prevention setting.

Journal of the American …, 2004

We sought to characterize the impact of obesity on vascular function in adolescents and to determ... more We sought to characterize the impact of obesity on vascular function in adolescents and to determine whether an exercise program reverses abnormalities in endothelial function. BACKGROUND Obesity, a major modifiable risk factor for cardiovascular disease, is epidemic in Western societies, with rapid rates of increase in the young. Atherosclerosis begins in childhood, and endothelial dysfunction is its earliest detectable manifestation. METHODS The influence of eight weeks of circuit training (CT) was examined in 19 obese subjects (14.3 Ϯ 1.5 years), using a randomized, crossover protocol. Functional capacity and muscular strength were assessed by standard techniques. Body composition was examined using anthropometric measures and dual-energy X-ray absorptiometry. Conduit vessel endothelial function was assessed using high-resolution ultrasound and flow-mediated dilation (FMD) of the brachial artery. RESULTS Circuit training decreased abdominal and trunk fat and significantly improved fitness and muscular strength (p Ͻ 0.05). In the obese group, FMD was significantly impaired relative to control subjects (n ϭ 20) at entry (5.3 Ϯ 0.9% vs. 8.9 Ϯ 1.5%, p Ͻ 0.05) and was normalized after CT (8.8 Ϯ 0.8%, p Ͻ 0.05). CONCLUSIONS Circuit training improved functional capacity, muscular strength, and body composition in obese adolescents. Furthermore, conduit vessel function was normalized after exercise training. If vascular dysfunction is an integral component of the pathogenesis of vascular disease, this study supports the value of an exercise program in the management of obese adolescents.

Journal of Bone …, 2008

Vitamin D insufficiency (VDI) is widely reported. In patients with normal PTH, the diagnosis rest... more Vitamin D insufficiency (VDI) is widely reported. In patients with normal PTH, the diagnosis rests on increases in fractional calcium absorption (FCA) when 25(OH)D increases above 30 ng/ml. However, estimates of increased FCA after correction of VDI vary dramatically, depending on study methods. We used a dual stable calcium isotope to clarify the impact of vitamin D repletion on FCA in postmenopausal women with VDI. We hypothesized that FCA would increase with vitamin D repletion. We studied postmenopausal women with VDI [25(OH)D ‫ס‬ 16-24 ng/ml] and an estimated calcium intake Յ1100 mg daily. Exclusion criteria included hypercalcemia, hypercalciuria, renal insufficiency, nephrolithiasis, gastrointestinal disorders, osteomalacia, prior adult fragility fracture, baseline T-score < −3.0, and use of medications known to interfere with vitamin D or calcium metabolism. Each woman underwent inpatient FCA studies before and after correction of VDI. We used ergocalciferol 50,000 IU/d for 15 days to achieve vitamin D repletion. During each study, women consumed their typical diet. They ingested 44 Ca orally with breakfast and received 42 Ca intravenously. We collected urine for 24 h and measured its calcium isotope content by mass spectrometry. Eighteen women completed the study; all but two had normal PTH. During the first and second FCA studies, their mean 25(OH)D level was 22 ± 4 and 64 ± 21 ng/ml, respectively (p < 0.001). Subjects' average FCA was 24 ± 7% initially and 27 ± 6% after vitamin D repletion (p ‫ס‬ 0.04). Thus, FCA increased by 3 ± 1% with correction of VDI. Postmenopausal women with VDI experience small FCA increments with vitamin D therapy. In existing literature, this small change in FCA does not associate with lower fracture rates or consistently higher bone mass. Future studies should ascertain whether small FCA increments favorably affect the skeleton.

Association for Science Teacher Education, St. Louis, MO, 2008

Scientific modeling is a crucial scientific practice, yet it is rarely incorporated into elementa... more Scientific modeling is a crucial scientific practice, yet it is rarely incorporated into elementary and middle school classrooms. Teachers typically have limited knowledge of models and modeling or of students' ideas about models and modeling. Yet engaging in scientific modeling in the classroom places a high demand on teachers, and they typically do not have access to highquality modeling-oriented curriculum materials. The MoDeLS project works to design innovative and effective supports for teachers' learning around ...

Journal of Research in Science Teaching, Aug 1, 2009

Modeling is a core practice in science and a central part of scientific literacy. We present theo... more Modeling is a core practice in science and a central part of scientific literacy. We present theoretical and empirical motivation for a learning progression for scientific modeling that aims to make the practice accessible and meaningful for learners. We define scientific modeling as including the elements of the practice (constructing, using, evaluating, and revising scientific models) and the metaknowledge that guides and motivates the practice (eg, understanding the nature and purpose of models). Our learning progression ...