Susana Diaz - Academia.edu (original) (raw)
Papers by Susana Diaz
2017 Joint 17th World Congress of International Fuzzy Systems Association and 9th International Conference on Soft Computing and Intelligent Systems (IFSA-SCIS), 2017
The purpose of this contribution is to study two important principles in collective aggregation t... more The purpose of this contribution is to study two important principles in collective aggregation theories, namely, liberalism and dictatorship, in the fuzzy context. We prove that two characterizations of liberalism in the crisp setting and a recent impossibility theorem can be extended to the fuzzy context under some minor requirements. Thus we provide characterizations of liberalism and an impossiblility theorem in the context of imprecise classification of alternatives. In the analysis of liberalism we assume that the objects to be classified and the individuals that provide that classification coincide, this is to say, that the members of a society classify themselves. However, dictatorship is studied in the more general context where individuals classify unrestricted alternatives.
Occupational and environmental health, 2021
BMJ Supportive & Palliative Care, 2020
BackgroundInternational organisations recommend the inclusion of palliative care undergraduate ed... more BackgroundInternational organisations recommend the inclusion of palliative care undergraduate education as a way to meet increasing demand; the long-term effects, however, are unknown. Since 2013 the Dr José Matías Delgado University has offered an undergraduate course for palliative care.AimsTo assess whether a palliative care course results in improvement in self-perceived comfort among students and if it lasts up to 4 years later; and to examine students’ knowledge of palliative care and assess the relationship between comfort and knowledge.DesignThis is a prospective cohort study where students attending the course were requested to complete the Scale of Self-Perceived Comfort in palliative care pre and post course. Participants were contacted in 2018 and a group without palliative care education was established as a control group, matched one-to-one according to current academic level. They were asked to complete the Scale of Self-Perceived Comfort questionnaire together with ...
Signa: Revista de la Asociación Española de Semiótica, 2011
Este artículo plantea la necesidad de situar el análisis de las relaciones entre imagen y relato ... more Este artículo plantea la necesidad de situar el análisis de las relaciones entre imagen y relato en un debate que aborde epistemológicamente el estatuto de la imagen tecnológica en la sociedad de la información, así como de las presuposiciones que acompañan a aquella en el imaginario espectatorial.
Prosopopeya Revista De Critica Contemporanea, 2007
Comunicacion Revista Internacional De Comunicacion Audiovisual Publicidad Y Estudios Culturales, 2012
En el panorama audiovisual de los últimos 25 años uno de los recursos más frecuentes es el remake... more En el panorama audiovisual de los últimos 25 años uno de los recursos más frecuentes es el remake de productos de éxito masivo en cualquier lugar del mundo por parte de cinematografías y/o televisiones muy diferentes a aquellas a las que pertenece el modelo original. Pocas veces la crítica se ha detenido en analizar las implicaciones del cambio de modo de representación que ello comporta, tanto en el terreno discursivo como en el de la construcción de nuevos sujetos espectatoriales. Este trabajo aborda la cuestión a partir de la doble adaptación (para público suecoalemán en formato cine y para público británico en formato TV) de una misma novela de Henning Mankell, La 5ª mujer.
Revista Medica Herediana, 2013
Entre 1988-1989, se estudiaron 86 cepas de Mycobacterium tuberculosis aisladas de esputos de paci... more Entre 1988-1989, se estudiaron 86 cepas de Mycobacterium tuberculosis aisladas de esputos de pacientes vírgenes al tratamiento y provenientes de las Unidades Departamentales de Salud de Lima, Callao y la Libertad. El objetivo fue determinar lascifras de resistencia inicial a drogas antituberculosas en áreas del Perú donde la prevalencia de tuberculosis es poco más del 50% del total nacional. En promedio se encontró una resistencia inicial para una o más drogas antituberculosas de 30.2%. Los porcentajes más altos de resistencia se encontraron en la provincia del Callao (43.7%), seguida de Lima (30.3%) y la Libertad (9.5%). El análisis de resistencia a una sola droga muestra una RI de 17.4% para estreptomicina, 3.5% para isoniacida, 2.3% para etambutol y 1.2% para rifampicina; sin embargo, estos porcentajes de resistencia aumentan cuando la droga se la considera asociada a otras drogas. Así, corresponde 22% a estreptomicina, 9.3% a isoniacida, 5.8% a rifampicina. Los resultados demues...
Proceedings of the 2015 Conference of the International Fuzzy Systems Association and the European Society for Fuzzy Logic and Technology, 2015
In the setting of fuzzy choice functions (Georgescu [6]), we explore the relationships among know... more In the setting of fuzzy choice functions (Georgescu [6]), we explore the relationships among known and new consistency axioms. Then we define the notion of sequential application of fuzzy choice functions, and investigate its normative implications. The Fuzzy Arrow Axiom is preserved by this sequential procedure, which ensures that full-rationality is preserved too.
Proceedings of the 2015 Conference of the International Fuzzy Systems Association and the European Society for Fuzzy Logic and Technology, 2015
Probabilistic and fuzzy choice theory are used to describe decision situations in which a certain... more Probabilistic and fuzzy choice theory are used to describe decision situations in which a certain degree of imprecision is involved. In this work we propose a correspondence between probabilistic and fuzzy choice functions, based on implication operators. Given a probabilistic choice function a fuzzy choice function can be constructed and, furthermore, a new set of rationality conditions is proposed. Finally, we prove that under those conditions, the associated fuzzy choice function fulfills desirable rationality properties.
The field of atmospheric ultraviolet radiation (UV) research is plagued with difficulties in nome... more The field of atmospheric ultraviolet radiation (UV) research is plagued with difficulties in nomenclature. The problems arise from (a) the strong wavelength dependence of UV radiation received at the Earth’s surface, (b) the ad-hoc way disparate groups have approached the subject and (c) the incorrect use of units when action spectra for different UV effects are incorporated. This report highlights some of the issues, taking vitamin-D synthesis, a beneficial effect, as a specific example. Standard vitamin-D dose (SDD) and minimum vitamin-D dose (MDD) are proposed, analogous to the standard erythema dose (SED) and minimum erythema dose (MED) that are in common use for erythema. In recognition of the fact that currently accepted action spectra may be revised in future if new data become available, it is recommended that spectrally resolved irradiance measurements are maintained and continued so that biologically effective irradiances and doses may be reprocessed.
Cellular & molecular biology letters, 2003
The amplified fragment length polymorphism (AFLP) technique was applied to identify palm varietie... more The amplified fragment length polymorphism (AFLP) technique was applied to identify palm varieties. Fluorescence labelled primers were used in selective amplifications and the amplified fragments were detected on capillary gel electrophoresis using an automated DNA sequencer with the analysis fragment option. This is a rapid and efficient technique for detecting a large number of DNA markers on the date palm. Phoenix dactylifera L. varieties Bou-Fegous, Medjool, and E-528 from Estación Phoenix (Elche), Spain, were analysed, yielding a total of 310 AFLP fragments derived from five primer combinations. The process for regenerating the date palm cultivars from in vitro tissue culture should yield individuals phenotypically and genetically identical to the explant they are derived from. The AFLP markers obtained were successfully used for comparing and identifying vitroplants of palm.
The problem of embedding incomplete into complete relations has been an important topic of resear... more The problem of embedding incomplete into complete relations has been an important topic of research in the context of crisp relations. After Szpilrajn’s result, several variations have been published. Alcantud studied in Economic Theory (2009) the case where the extension is asked to satisfy some order conditions between elements. He first studied and solved a particular formulation where conditions are imposed in terms of strict preference only, which helps to precisely identify which quasiorderings can be extended when we allow for additional conditions in terms of indifference too. In this contribution we generalize both results to the fuzzy case.
Nursing (Ed. española), 2012
AIP Conference Proceedings, 2009
Photochemistry and Photobiology, 2006
Ozone and UV radiation were analyzed at eight stations from tropical to sub-Antarctic regions in ... more Ozone and UV radiation were analyzed at eight stations from tropical to sub-Antarctic regions in South America. Ground UV irradiances were measured by multichannel radiometers as part of the Inter American Institute for Global Change Radiation network. The irradiance channels used for this study were centered at 305 nm (for UV-B measurements) and 340 nm (for UV-A measurements). Results were presented as daily maximum irradiances, as monthly averaged, daily integrated irradiances and as the ratio of 305 nm to 340 nm. These findings are the first to be based on a long time series of semispectral data from the southern region of South America. As expected, the UV-B channel and total column ozone varied with latitude. The pattern of the UV-A channel was more complex because of local atmospheric conditions. Total column ozone levels of <220 Dobson Units were observed at all sites. Analysis of autocorrelations showed a larger persistence of total column ozone level than irradiance. A decreasing cross-correlation coefficient between 305 and 340 nm and an increasing cross-correlation coefficient between 305 nm and ozone were observed at higher latitudes, indicating that factors such as cloud cover tend to dominate at northern sites and that ozone levels tend to dominate at southern sites. These results highlight the value of long-term monitoring of radiation with multichannel radio-meters to determine climatological data and evaluate the combination of factors affecting ground UV radiation.
Photochemical & Photobiological Sciences, 2011
Ultraviolet radiation (UVR) plays a key role in several biological functions, including human hea... more Ultraviolet radiation (UVR) plays a key role in several biological functions, including human health. Skin exposure to UVR is the main factor in vitamin D photoconversion. There is also evidence relating low levels of vitamin D with certain internal cancers, mainly colon, breast and prostate, as well as other diseases. Several epidemiological studies have shown an inverse relationship between the above-mentioned diseases and latitude, in accordance with the ultraviolet radiation latitudinal gradient. The aim of this study is to determine whether UV irradiance levels in the southern South America are sufficient to produce suitable levels of vitamin D year around. For this purpose, vitamin D photoconversion weighted-irradiance was analyzed between S.S. de Jujuy (24.17 • S, 65.02 • W) and Ushuaia (54 • 50¢S, 68 • 18¢W). In addition to irradiance, skin type and area of body exposed to sunlight are critical factors in vitamin D epidemiology. Due to a broad ethnic variability, it was assumed that the skin type in this region varies between II and V (from the most to the less sensitive). All sites except South Patagonia indicate that skin II under any condition of body area exposure and skin V when exposing head, hands, arms and legs, would produce suitable levels of vitamin D year round (except for some days in winter at North Patagonian sites). At South Patagonian sites, minimum healthy levels of vitamin D year round can be reached only by the more sensitive skin II type, if exposing head, hands, arms and legs, which is not a realistic scenario during winter. At these southern latitudes, healthy vitamin D levels would not be obtained between mid May and beginning of August if exposing only the head. Skin V with head exposure is the most critical situation; with the exception of the tropics, sun exposure would not produce suitable levels of vitamin D around winter, during a time period that varies with latitude. Analyzing the best exposure time during the day in order to obtain a suitable level of vitamin D without risk of sunburn, it was concluded that noon is best during winter, as determined previously. For skin type II when exposing head, exposure period in winter varies between 30 and 130 min, according to latitude, except for South Patagonian sites. During summer, noon seems to be a good time of day for short periods of exposure, while during leisure times, longer periods of exposure without risk of sunburn are possible at mid-morning and mid-afternoon. At 3 h from noon, solar zenith angles are almost the same for sites between the tropics and North Patagonia, and at 4 h from noon, for all sites. Then, in these cases, the necessary exposure periods varied slightly between sites, only due to meteorological differences.
Nature, 2010
On 21 May the US government announced a US$1-billion programme to boost hiring and production at ... more On 21 May the US government announced a US$1-billion programme to boost hiring and production at biotechnology companies with fewer than 250 workers. The initiative is part of the Therapeutic Discovery Project Program created by the US health-care legislation signed into law on 23 March. Awards will be tax credits or grants to cover up to 50% of basic research costs, and the US Treasury says that one criterion for earning grants will be the potential to create or sustain jobs. The economic downturn has caused layoffs and project delays throughout the industry, says Alan Eisenberg, of the Washington DC-based Biotechnology Industry Organization. "This infusion of cash will help companies get to the next milestone, " he says. UK tuition rise needed? The Russell Group of 20 elite research universities in the United Kingdom warns that tuition fees must rise if UK universities are to keep their global reputations and stay competitive. Fees are currently capped at £3,225 (US$4,632) a year. The group said in a May 2010 report that additional funding from public and private sources does not meet needs. The report does recommend, however, that more public funds be applied to science, technology, engineering and maths courses, to defray their higher costs so that students are not discouraged from enrolling. The Russell Group includes the universities of Oxford and Cambridge among other institutions.
Journal of the American College of Cardiology, 2003
Journal of Bone and Mineral Research, 2009
The incidence of nutritional rickets in the southern part of Argentina is 8-12 times higher than ... more The incidence of nutritional rickets in the southern part of Argentina is 8-12 times higher than in the rest of the country. Winter 25(OH)D serum levels in normal population of southern areas are lower than in central and northern areas. To elucidate these differences, we compared the photoconversion of provitamin D, (7-DHC) to previtamin D, in two cities: Ushuaia (latitude 55"s) and Buenos Aires (34"s). Ampules containing 7-DHC were exposed to sunlight one day in the middle of each month either from 1030 a.m. to 2:30 p.m. or from SO0 a.m. to 500 p.m. The percentages of photoproducts formed were determined by high performance liquid chromatography (HPLC). Previous studies have proved that this is a valid model to assess "in vitro" the photoproduction of vitamin D, in human skin. Previtamin D, + vitamin D, formed in Ushuaia were less (p < 0.02) than those found in Buenos Ares during all seasons: summer, (X f SEM) 6.4 2 0.8% vs. 13.2 f 1.8%; autumn, 1.2 f 0.7% vs. 6 3 f 1.3%; winter, 0.8 f 0.7% vs. 3.6 f 0.7%; spring, 3.4 f 0.5% vs. 9.1 f 1.1%. The photoproducts produced from 1030 a.m. to 230 p.m. were similar for each month and latitude to those formed when the ampules were exposed from 8:OO a.m. to 500 p.m. We conclude that in Ushuaia there is a prolonged "vitamin D winter" during which cutaneous synthesis of vitamin D is absent, leading to lower serum values of 25(OH)D and contributing to the higher incidence of rickets.
2017 Joint 17th World Congress of International Fuzzy Systems Association and 9th International Conference on Soft Computing and Intelligent Systems (IFSA-SCIS), 2017
The purpose of this contribution is to study two important principles in collective aggregation t... more The purpose of this contribution is to study two important principles in collective aggregation theories, namely, liberalism and dictatorship, in the fuzzy context. We prove that two characterizations of liberalism in the crisp setting and a recent impossibility theorem can be extended to the fuzzy context under some minor requirements. Thus we provide characterizations of liberalism and an impossiblility theorem in the context of imprecise classification of alternatives. In the analysis of liberalism we assume that the objects to be classified and the individuals that provide that classification coincide, this is to say, that the members of a society classify themselves. However, dictatorship is studied in the more general context where individuals classify unrestricted alternatives.
Occupational and environmental health, 2021
BMJ Supportive & Palliative Care, 2020
BackgroundInternational organisations recommend the inclusion of palliative care undergraduate ed... more BackgroundInternational organisations recommend the inclusion of palliative care undergraduate education as a way to meet increasing demand; the long-term effects, however, are unknown. Since 2013 the Dr José Matías Delgado University has offered an undergraduate course for palliative care.AimsTo assess whether a palliative care course results in improvement in self-perceived comfort among students and if it lasts up to 4 years later; and to examine students’ knowledge of palliative care and assess the relationship between comfort and knowledge.DesignThis is a prospective cohort study where students attending the course were requested to complete the Scale of Self-Perceived Comfort in palliative care pre and post course. Participants were contacted in 2018 and a group without palliative care education was established as a control group, matched one-to-one according to current academic level. They were asked to complete the Scale of Self-Perceived Comfort questionnaire together with ...
Signa: Revista de la Asociación Española de Semiótica, 2011
Este artículo plantea la necesidad de situar el análisis de las relaciones entre imagen y relato ... more Este artículo plantea la necesidad de situar el análisis de las relaciones entre imagen y relato en un debate que aborde epistemológicamente el estatuto de la imagen tecnológica en la sociedad de la información, así como de las presuposiciones que acompañan a aquella en el imaginario espectatorial.
Prosopopeya Revista De Critica Contemporanea, 2007
Comunicacion Revista Internacional De Comunicacion Audiovisual Publicidad Y Estudios Culturales, 2012
En el panorama audiovisual de los últimos 25 años uno de los recursos más frecuentes es el remake... more En el panorama audiovisual de los últimos 25 años uno de los recursos más frecuentes es el remake de productos de éxito masivo en cualquier lugar del mundo por parte de cinematografías y/o televisiones muy diferentes a aquellas a las que pertenece el modelo original. Pocas veces la crítica se ha detenido en analizar las implicaciones del cambio de modo de representación que ello comporta, tanto en el terreno discursivo como en el de la construcción de nuevos sujetos espectatoriales. Este trabajo aborda la cuestión a partir de la doble adaptación (para público suecoalemán en formato cine y para público británico en formato TV) de una misma novela de Henning Mankell, La 5ª mujer.
Revista Medica Herediana, 2013
Entre 1988-1989, se estudiaron 86 cepas de Mycobacterium tuberculosis aisladas de esputos de paci... more Entre 1988-1989, se estudiaron 86 cepas de Mycobacterium tuberculosis aisladas de esputos de pacientes vírgenes al tratamiento y provenientes de las Unidades Departamentales de Salud de Lima, Callao y la Libertad. El objetivo fue determinar lascifras de resistencia inicial a drogas antituberculosas en áreas del Perú donde la prevalencia de tuberculosis es poco más del 50% del total nacional. En promedio se encontró una resistencia inicial para una o más drogas antituberculosas de 30.2%. Los porcentajes más altos de resistencia se encontraron en la provincia del Callao (43.7%), seguida de Lima (30.3%) y la Libertad (9.5%). El análisis de resistencia a una sola droga muestra una RI de 17.4% para estreptomicina, 3.5% para isoniacida, 2.3% para etambutol y 1.2% para rifampicina; sin embargo, estos porcentajes de resistencia aumentan cuando la droga se la considera asociada a otras drogas. Así, corresponde 22% a estreptomicina, 9.3% a isoniacida, 5.8% a rifampicina. Los resultados demues...
Proceedings of the 2015 Conference of the International Fuzzy Systems Association and the European Society for Fuzzy Logic and Technology, 2015
In the setting of fuzzy choice functions (Georgescu [6]), we explore the relationships among know... more In the setting of fuzzy choice functions (Georgescu [6]), we explore the relationships among known and new consistency axioms. Then we define the notion of sequential application of fuzzy choice functions, and investigate its normative implications. The Fuzzy Arrow Axiom is preserved by this sequential procedure, which ensures that full-rationality is preserved too.
Proceedings of the 2015 Conference of the International Fuzzy Systems Association and the European Society for Fuzzy Logic and Technology, 2015
Probabilistic and fuzzy choice theory are used to describe decision situations in which a certain... more Probabilistic and fuzzy choice theory are used to describe decision situations in which a certain degree of imprecision is involved. In this work we propose a correspondence between probabilistic and fuzzy choice functions, based on implication operators. Given a probabilistic choice function a fuzzy choice function can be constructed and, furthermore, a new set of rationality conditions is proposed. Finally, we prove that under those conditions, the associated fuzzy choice function fulfills desirable rationality properties.
The field of atmospheric ultraviolet radiation (UV) research is plagued with difficulties in nome... more The field of atmospheric ultraviolet radiation (UV) research is plagued with difficulties in nomenclature. The problems arise from (a) the strong wavelength dependence of UV radiation received at the Earth’s surface, (b) the ad-hoc way disparate groups have approached the subject and (c) the incorrect use of units when action spectra for different UV effects are incorporated. This report highlights some of the issues, taking vitamin-D synthesis, a beneficial effect, as a specific example. Standard vitamin-D dose (SDD) and minimum vitamin-D dose (MDD) are proposed, analogous to the standard erythema dose (SED) and minimum erythema dose (MED) that are in common use for erythema. In recognition of the fact that currently accepted action spectra may be revised in future if new data become available, it is recommended that spectrally resolved irradiance measurements are maintained and continued so that biologically effective irradiances and doses may be reprocessed.
Cellular & molecular biology letters, 2003
The amplified fragment length polymorphism (AFLP) technique was applied to identify palm varietie... more The amplified fragment length polymorphism (AFLP) technique was applied to identify palm varieties. Fluorescence labelled primers were used in selective amplifications and the amplified fragments were detected on capillary gel electrophoresis using an automated DNA sequencer with the analysis fragment option. This is a rapid and efficient technique for detecting a large number of DNA markers on the date palm. Phoenix dactylifera L. varieties Bou-Fegous, Medjool, and E-528 from Estación Phoenix (Elche), Spain, were analysed, yielding a total of 310 AFLP fragments derived from five primer combinations. The process for regenerating the date palm cultivars from in vitro tissue culture should yield individuals phenotypically and genetically identical to the explant they are derived from. The AFLP markers obtained were successfully used for comparing and identifying vitroplants of palm.
The problem of embedding incomplete into complete relations has been an important topic of resear... more The problem of embedding incomplete into complete relations has been an important topic of research in the context of crisp relations. After Szpilrajn’s result, several variations have been published. Alcantud studied in Economic Theory (2009) the case where the extension is asked to satisfy some order conditions between elements. He first studied and solved a particular formulation where conditions are imposed in terms of strict preference only, which helps to precisely identify which quasiorderings can be extended when we allow for additional conditions in terms of indifference too. In this contribution we generalize both results to the fuzzy case.
Nursing (Ed. española), 2012
AIP Conference Proceedings, 2009
Photochemistry and Photobiology, 2006
Ozone and UV radiation were analyzed at eight stations from tropical to sub-Antarctic regions in ... more Ozone and UV radiation were analyzed at eight stations from tropical to sub-Antarctic regions in South America. Ground UV irradiances were measured by multichannel radiometers as part of the Inter American Institute for Global Change Radiation network. The irradiance channels used for this study were centered at 305 nm (for UV-B measurements) and 340 nm (for UV-A measurements). Results were presented as daily maximum irradiances, as monthly averaged, daily integrated irradiances and as the ratio of 305 nm to 340 nm. These findings are the first to be based on a long time series of semispectral data from the southern region of South America. As expected, the UV-B channel and total column ozone varied with latitude. The pattern of the UV-A channel was more complex because of local atmospheric conditions. Total column ozone levels of <220 Dobson Units were observed at all sites. Analysis of autocorrelations showed a larger persistence of total column ozone level than irradiance. A decreasing cross-correlation coefficient between 305 and 340 nm and an increasing cross-correlation coefficient between 305 nm and ozone were observed at higher latitudes, indicating that factors such as cloud cover tend to dominate at northern sites and that ozone levels tend to dominate at southern sites. These results highlight the value of long-term monitoring of radiation with multichannel radio-meters to determine climatological data and evaluate the combination of factors affecting ground UV radiation.
Photochemical & Photobiological Sciences, 2011
Ultraviolet radiation (UVR) plays a key role in several biological functions, including human hea... more Ultraviolet radiation (UVR) plays a key role in several biological functions, including human health. Skin exposure to UVR is the main factor in vitamin D photoconversion. There is also evidence relating low levels of vitamin D with certain internal cancers, mainly colon, breast and prostate, as well as other diseases. Several epidemiological studies have shown an inverse relationship between the above-mentioned diseases and latitude, in accordance with the ultraviolet radiation latitudinal gradient. The aim of this study is to determine whether UV irradiance levels in the southern South America are sufficient to produce suitable levels of vitamin D year around. For this purpose, vitamin D photoconversion weighted-irradiance was analyzed between S.S. de Jujuy (24.17 • S, 65.02 • W) and Ushuaia (54 • 50¢S, 68 • 18¢W). In addition to irradiance, skin type and area of body exposed to sunlight are critical factors in vitamin D epidemiology. Due to a broad ethnic variability, it was assumed that the skin type in this region varies between II and V (from the most to the less sensitive). All sites except South Patagonia indicate that skin II under any condition of body area exposure and skin V when exposing head, hands, arms and legs, would produce suitable levels of vitamin D year round (except for some days in winter at North Patagonian sites). At South Patagonian sites, minimum healthy levels of vitamin D year round can be reached only by the more sensitive skin II type, if exposing head, hands, arms and legs, which is not a realistic scenario during winter. At these southern latitudes, healthy vitamin D levels would not be obtained between mid May and beginning of August if exposing only the head. Skin V with head exposure is the most critical situation; with the exception of the tropics, sun exposure would not produce suitable levels of vitamin D around winter, during a time period that varies with latitude. Analyzing the best exposure time during the day in order to obtain a suitable level of vitamin D without risk of sunburn, it was concluded that noon is best during winter, as determined previously. For skin type II when exposing head, exposure period in winter varies between 30 and 130 min, according to latitude, except for South Patagonian sites. During summer, noon seems to be a good time of day for short periods of exposure, while during leisure times, longer periods of exposure without risk of sunburn are possible at mid-morning and mid-afternoon. At 3 h from noon, solar zenith angles are almost the same for sites between the tropics and North Patagonia, and at 4 h from noon, for all sites. Then, in these cases, the necessary exposure periods varied slightly between sites, only due to meteorological differences.
Nature, 2010
On 21 May the US government announced a US$1-billion programme to boost hiring and production at ... more On 21 May the US government announced a US$1-billion programme to boost hiring and production at biotechnology companies with fewer than 250 workers. The initiative is part of the Therapeutic Discovery Project Program created by the US health-care legislation signed into law on 23 March. Awards will be tax credits or grants to cover up to 50% of basic research costs, and the US Treasury says that one criterion for earning grants will be the potential to create or sustain jobs. The economic downturn has caused layoffs and project delays throughout the industry, says Alan Eisenberg, of the Washington DC-based Biotechnology Industry Organization. "This infusion of cash will help companies get to the next milestone, " he says. UK tuition rise needed? The Russell Group of 20 elite research universities in the United Kingdom warns that tuition fees must rise if UK universities are to keep their global reputations and stay competitive. Fees are currently capped at £3,225 (US$4,632) a year. The group said in a May 2010 report that additional funding from public and private sources does not meet needs. The report does recommend, however, that more public funds be applied to science, technology, engineering and maths courses, to defray their higher costs so that students are not discouraged from enrolling. The Russell Group includes the universities of Oxford and Cambridge among other institutions.
Journal of the American College of Cardiology, 2003
Journal of Bone and Mineral Research, 2009
The incidence of nutritional rickets in the southern part of Argentina is 8-12 times higher than ... more The incidence of nutritional rickets in the southern part of Argentina is 8-12 times higher than in the rest of the country. Winter 25(OH)D serum levels in normal population of southern areas are lower than in central and northern areas. To elucidate these differences, we compared the photoconversion of provitamin D, (7-DHC) to previtamin D, in two cities: Ushuaia (latitude 55"s) and Buenos Aires (34"s). Ampules containing 7-DHC were exposed to sunlight one day in the middle of each month either from 1030 a.m. to 2:30 p.m. or from SO0 a.m. to 500 p.m. The percentages of photoproducts formed were determined by high performance liquid chromatography (HPLC). Previous studies have proved that this is a valid model to assess "in vitro" the photoproduction of vitamin D, in human skin. Previtamin D, + vitamin D, formed in Ushuaia were less (p < 0.02) than those found in Buenos Ares during all seasons: summer, (X f SEM) 6.4 2 0.8% vs. 13.2 f 1.8%; autumn, 1.2 f 0.7% vs. 6 3 f 1.3%; winter, 0.8 f 0.7% vs. 3.6 f 0.7%; spring, 3.4 f 0.5% vs. 9.1 f 1.1%. The photoproducts produced from 1030 a.m. to 230 p.m. were similar for each month and latitude to those formed when the ampules were exposed from 8:OO a.m. to 500 p.m. We conclude that in Ushuaia there is a prolonged "vitamin D winter" during which cutaneous synthesis of vitamin D is absent, leading to lower serum values of 25(OH)D and contributing to the higher incidence of rickets.