José Flores - Academia.edu (original) (raw)

Papers by José Flores

Research paper thumbnail of Nuevas Aportaciones a La Biogeografía De Cocolitóforos En El Pacífico Ecuatorial Y Suroriental

Research paper thumbnail of Geological record and reconstruction of the late Pliocene impact of the Eltanin asteroid in the Southern Ocean

In 1995, an expedition on board the research vessel FS Polarstern explored the impact site of the... more In 1995, an expedition on board the research vessel FS Polarstern explored the impact site of the Eltanin asteroid in the Southern Ocean, the only known asteroid impact into a deep ocean basin. Analyses of the geological record of the impact region place the event in the late Pliocene (ϳ2.15 Myr) and constrain the size of the asteroid to be Ͼ1 km. The explosive force inferred for this event places it at the threshold of impacts believed to have global consequences, and its study should therefore provide a baseline for the reconstruction and modelling of similar events, which are common on geological timescales.

Research paper thumbnail of SNAP23 Is Selectively Expressed in Airway Secretory Cells and Mediates Baseline and Stimulated Mucin Secretion

Bioscience Reports, 2015

Airway mucin secretion is important pathophysiologically and as a model of polarized epithelial r... more Airway mucin secretion is important pathophysiologically and as a model of polarized epithelial regulated exocytosis. We find the trafficking protein, SNAP23 (23-kDa paralogue of synaptosome-associated protein of 25 kDa), selectively expressed in secretory cells compared with ciliated and basal cells of airway epithelium by immunohistochemistry and FACS, suggesting that SNAP23 functions in regulated but not constitutive epithelial secretion. Heterozygous SNAP23 deletant mutant mice show spontaneous accumulation of intracellular mucin, indicating a defect in baseline secretion. However mucins are released from perfused tracheas of mutant and wild-type (WT) mice at the same rate, suggesting that increased intracellular stores balance reduced release efficiency to yield a fully compensated baseline steady state. In contrast, acute stimulated release of intracellular mucin from mutant mice is impaired whether measured by a static imaging assay 5 min after exposure to the secretagogue ATP or by kinetic analysis of mucins released from perfused tracheas during the first 10 min of ATP exposure. Together, these data indicate that increased intracellular stores cannot fully compensate for the defect in release efficiency during intense stimulation. The lungs of mutant mice develop normally and clear bacteria and instilled polystyrene beads comparable to WT mice, consistent with these functions depending on baseline secretion that is fully compensated.

Research paper thumbnail of Evaluation of the time of uncapping and removing dead brood from cells by hygienic and non-hygienic honey bees

Genetics and molecular research : GMR, 2005

Most research on hygienic behavior has recorded the time taken by the colony to remove an experim... more Most research on hygienic behavior has recorded the time taken by the colony to remove an experimental amount of dead brood, usually after one or two days. We evaluated the time that hygienic (H) and non-hygienic (NH) honey bees take to uncap and remove dead brood in observation hives after the brood was killed using the pin-killing assay. Four experimental colonies were selected as the extreme cases among 108 original colonies. Thirty brood cells were perforated with a pin in two H and two NH colonies and observations were made after 1, 2, 3, 4, 5, 6, and 24 h. Different stages of uncapping and removing were recorded. Differences in uncapping and removal between H and NH colonies were significant for all comparisons made at the different times after perforation. Using observation hives one obtains a better and faster discrimination between H and NH colonies than in full size colonies. It is possible to differentiate H and NH within a few hours after perforating the cells.

Research paper thumbnail of Structure and dynamics of pollination networks: the role of alien plants

Oikos, 2009

Research on ecological communities, and plantÁpollinator mutualistic networks in particular, has ... more Research on ecological communities, and plantÁpollinator mutualistic networks in particular, has increasingly benefited from the theory and tools of complexity science. Nevertheless, up to now there have been few attempts to investigate the interplay between the structure of real pollination networks and their dynamics. This study is one of the first contributions to explore this issue. Biological invasions, of major concern for conservation, are also poorly understood from the perspective of complex ecological networks. In this paper we assess the role that established alien species play within a host community by analyzing the temporal changes in structural network properties driven by the removal of non-native plants. Three topological measures have been used to represent the most relevant structural properties for the stability of ecological networks: degree distribution, nestedness, and modularity. Therefore, we investigate for a detailed pollination network, 1) how its dynamics, represented as changes in species abundances, affect the evolution of its structure, 2) how topology relates to dynamics focusing on long-term species persistence; and 3) how both structure and dynamics are affected by the removal of alien plant species. Network dynamics were simulated by means of a stochastic metacommunity model. Our results showed that established alien plants are important for the persistence of the pollination network and for the maintenance of its structure. Removal of alien plants decreased the likelihood of species persistence. On the other hand, both the full network and the subset native network tended to lose their structure through time. Nevertheless, the structure of the full network was better preserved than the structure of the network without alien plants. Temporal topological shifts were evident in terms of degree distribution, nestedness, and modularity. However the effects of removing alien plants were more pronounced for degree distribution and modularity of the network. Therefore, elimination of alien plants affected the evolution of the architecture of the interaction web, which was closely related to the higher species loss found in the network where alien plants were removed.

Research paper thumbnail of The duration of the motor response to apomorphine boluses is conditioned by the length of a prior infusion in Parkinson's disease

Movement Disorders, 2009

&... more "Pulsatile" administration of levodopa has been invocated a relevant factor for motor fluctuations in Parkinson's disease (PD). We studied dopaminergic sensitivity to apomorphine in 10 parkinsonian patients with motor fluctuations. Patients were tested as follows: the minimal effective dose of apomorphine (MED-1) was administered in the morning to induce an on response. Fifteen minutes after this motor response had disappeared, an apomorphine infusion was initiated and maintained to ensure on periods of three different durations on different days. Infusion lasted for approximately 30, 60 and 90 minutes. Subsequently, the infusion was stopped, and after 15 minutes in the off state, a second bolus of apomorphine (MED-2) was given. The mean infusion doses were 49.2 +/- 5.4, 108.4 +/- 10.3, and 150 +/- 8.2 mg. These elicited on periods of 48.2 +/- 4.1, 110 +/- 4.5, and 195 +/- 3.8 minutes. The MED-2 elicited on responses with a duration of 30 +/- 4.5, 18.4 +/- 3.2, and 11.2 +/- 4.1 minutes. The duration of the on response induced by the apomorphine infusions correlated inversely (P < 0.01) with the on induced by the MED-2 of apomorphine. Our findings indicate that a continuous dopaminergic stimulus may induce pharmacodynamic changes associated with tolerance in PD patients.

Research paper thumbnail of Enterotoxigenic Escherichia coli Heat-Labile Toxin Seroconversion in US Travelers to Mexico

Journal of Travel Medicine, 2008

Enterotoxigenic Escherichia coli (ETEC) is the most common bacterial pathogen isolated from trave... more Enterotoxigenic Escherichia coli (ETEC) is the most common bacterial pathogen isolated from travelers suffering of diarrhea. Exposure to heat-labile toxin (LT) produces a high rate of seroconversion. However, the role of LT-producing ETEC (LT-ETEC) as a cause of diarrhea is controversial. We conducted a cohort study in US students traveling to Mexico to assess the ETEC-LT seroconversion rate after natural exposure. Participants provided a serum sample on arrival and departure and a stool sample when ill. ETEC-LT immunoglobulin G antibodies were measured by enzyme-linked immunosorbent assay, and LT-ETEC were detected by means of polymerase chain reaction done on fecal DNA. A total of 422 participants with a mean age of 34.5 years were followed a mean of 19.9 days; 304 were females (72.0%), and 319 (75.6%) traveled during the summer months. In total, 177 individuals (41.9%) developed travelers' diarrhea and 33.9% had LT-ETEC identified in their stools. Among individuals having an LT-ETEC strain, 74% seroconverted compared to 11% of those not having diarrhea (p < 0.0001). When analyzed with a logistic regression model, the odds of seroconversion were significantly reduced in participants not having LT-ETEC in their stool (odds ratio = 0.1, p < 0.0001) after adjusting for season, length of stay, age, gender, race, and ethnicity. In US young adults traveling to Mexico, ETEC-LT seroconversion reliably identifies individuals naturally exposed to ETEC and correlates with symptomatic illness, length and season of travel.

Research paper thumbnail of Measuring individual and cultural differences in implicit trait theories

Journal of Personality and Social Psychology, 2003

A new measure of implicit theories or beliefs regarding the traitedness versus contextuality of b... more A new measure of implicit theories or beliefs regarding the traitedness versus contextuality of behavior was developed and tested across cultures. In Studies 1 (N ϭ 266) and 2 (N ϭ 266), these implicit beliefs dimensions were reliably measured and replicated across U.S. college student samples and validity evidence was provided. In Study 3, their structure replicated well across an individualistic culture (the United States; N ϭ 249) and a collectivistic culture (Mexico; N ϭ 268). Implicit trait and contextual beliefs overlapped only modestly with implicit entity theory beliefs and were predicted by self-construals in ways that generally supported cultural psychology hypotheses. Implicit trait beliefs were fairly strongly endorsed in both cultures, suggesting that such beliefs may be universally held.

Research paper thumbnail of Seroprevalence of the enteroaggregative Escherichia coli virulence factor dispersin among USA travellers to Cuernavaca, Mexico: a pilot study

Journal of Medical Microbiology, 2008

This pilot study examined the change in the seroprevalence of the enteroaggregative Escherichia c... more This pilot study examined the change in the seroprevalence of the enteroaggregative Escherichia coli (EAEC) virulence factor dispersin in USA students during a short stay in Cuernavaca, Mexico, between June and August 2004. One hundred and ninety-five students provided paired serum samples -one on arrival to Mexico (pre-serum) and a second on departure from Mexico (post-serum) after a mean stay of 19 days. Serum samples were tested for IgG antibody to a recombinant purified dispersin protein by ELISA. For all travellers, with and without diarrhoea, the mean±SD pre-serum absorbance value (read at 450 and 570 nm) was 0.340±0.212 and the mean post-serum value was 0.513±0.316 (P,0.00001). Both travellers who developed diarrhoea and those who did not develop diarrhoea had an increase in IgG antibody to dispersin from the time of arrival to the time of departure from Cuernavaca (diarrhoea group 0.323±0.197 to 0.501±0.311, P,0.00001, and the asymptomatic group 0.354±0.224 to 0.525±0.321, P,0.00001). The pre-serum absorbance value (read at 450 and 570 nm) for IgG antibody to dispersin was not associated with protection against the development of diarrhoeal illness. These results indicate that USA travellers to Mexico show seroconversion for the EAEC virulence factor dispersin. Further studies are needed to characterize in more detail the host clinical and immunological responses to the dispersin protein.

Research paper thumbnail of PCR-Based Assay Using Occult Blood Detection Cards for Detection of Diarrheagenic Escherichia coli in Specimens from U.S. Travelers to Mexico with Acute Diarrhea

Journal of Clinical Microbiology, 2008

Large field studies of travelers' diarrhea for multiple destinations are limited by the need to p... more Large field studies of travelers' diarrhea for multiple destinations are limited by the need to perform stool cultures on site in a timely manner. A method for the collection, transport, and storage of fecal specimens that does not require immediate processing and refrigeration and that is stable for months would be advantageous. This study was designed to determine if enterotoxigenic Escherichia coli (ETEC) and enteroaggregative E. coli (EAEC) DNA could be identified from cards that were processed for the evaluation of fecal occult blood. U.S. students traveling to Mexico during 2005 to 2007 were monitored for the occurrence of diarrheal illness. When ill, students provided a stool specimen for culture and occult blood by the standard methods. Cards then were stored at room temperature prior to DNA extraction. Fecal PCR was performed to identify ETEC and EAEC in DNA extracted from stools and from occult blood cards. Significantly more EAEC cases were identified by PCR that was performed on DNA that was extracted from cards (49%) or from frozen feces (40%) than from culture methods that used HEp-2 adherence assays (13%) (P < 0.001). Similarly, more ETEC cases were detected from card DNA (38%) than from fecal DNA (30%) or by culture that was followed by hybridization (10%) (P < 0.001). The sensitivity and specificity of the card test were 75 and 62%, respectively, compared to those for EAEC by culture and were 50 and 63%, respectively, compared to those for ETEC. DNA extracted from fecal cards that was used for the detection of occult blood is of use in identifying diarrheagenic E. coli.

Research paper thumbnail of Modelling the management of fragmented forests: Is it possible to recover the original tree composition?

Forest Ecology and Management, 2008

In the fragmented Maulino forest (in Central Chile), differences in the relative frequencies of s... more In the fragmented Maulino forest (in Central Chile), differences in the relative frequencies of species between seedlings and mature trees are strong indicators of a changing replacement dynamics in the community. Stationary Markov chain models predict that the future tree composition such Maulino forest fragments will differ from that of continuous, intact forest. We found that the persistence probability was highest for Aristotelia chilensis and lowest for Nothofagus glauca. These two tree species are the most affected by fragmentation, and changes in their abundances appear to be the main drivers of the long-term change in stand composition. The aim of our study was to test if the management of just these two species would be sufficient to avoid long-term changes in the composition of forest fragments or would recover their composition toward a state more similar to the continuous forest. For this purpose, we constructed a Markov matrix model from published information, and calculated the future stable stand composition under different management simulations: (1) reduction of A. chilensis recruitment, (2) increased recruitment of N. glauca, and (3) a combined treatment. To evaluate the effectiveness of management treatments, the future composition of fragments was compared with the composition expected for continuous (i.e., undisturbed) Maulino forest. We performed a sensitivity analysis of the stable composition in order to assess the intensity of changes in the future composition driven by the treatments, and to determine to what extend the recruitment of other coexisting species contributes to changes in relative frequencies of A. chilensis and N. glauca.

Research paper thumbnail of Role of inducible defenses in the stability of a tritrophic system

Ecological Complexity, 2008

Inducible defenses are a form of phenotypic plasticity that potentially modify direct interaction... more Inducible defenses are a form of phenotypic plasticity that potentially modify direct interactions between various members of an ecological community, generating trait-mediated indirect effects. In this work, the hypothesis that inducible defenses increase the stability of tritrophic chains is tested, through the numerical analysis of a continuous-time model that discriminate between defenses affecting attack rate of predators, and defenses affecting

Research paper thumbnail of Consequences of double Allee effect on the number of limit cycles in a predator–prey model

Computers & Mathematics with Applications, 2011

The main goal of this work is to show a comparative analysis of simple continuous time predator–p... more The main goal of this work is to show a comparative analysis of simple continuous time predator–prey models considering the Allee effect affecting the prey population, also known as depensation in fisheries sciences. This phenomenon may be expressed by different ...

Research paper thumbnail of ALLEE EFFECT, EMIGRATION AND IMMIGRATION IN A CLASS OF PREDATOR-PREY MODELS

Biophysical Reviews and Letters, 2008

ALLEE EFFECT, EMIGRATION AND IMMIGRATION IN A CLASS OF PREDATOR-PREY MODELS∗EDUARDO GONZALEZ-OLIV... more ALLEE EFFECT, EMIGRATION AND IMMIGRATION IN A CLASS OF PREDATOR-PREY MODELS∗EDUARDO GONZALEZ-OLIVARES, JAIME MENA-LORCA HECTOR MENESES-ALCAY, BETSABE GONZALEZ-YANEZ Grupo Ecologıa Matematica, Instituto de Matematicas ...

Research paper thumbnail of A review of estimation of distribution algorithms in bioinformatics

BioData Mining, 2008

Evolutionary search algorithms have become an essential asset in the algorithmic toolbox for solv... more Evolutionary search algorithms have become an essential asset in the algorithmic toolbox for solving high-dimensional optimization problems in across a broad range of bioinformatics problems. Genetic algorithms, the most well-known and representative evolutionary search technique, have been the subject of the major part of such applications. Estimation of distribution algorithms (EDAs) offer a novel evolutionary paradigm that constitutes a natural and attractive alternative to genetic algorithms. They make use of a probabilistic model, learnt from the promising solutions, to guide the search process. In this paper, we set out a basic taxonomy of EDA techniques, underlining the nature and complexity of the probabilistic model of each EDA variant. We review a set of innovative works that make use of EDA techniques to solve challenging bioinformatics problems, emphasizing the EDA paradigm's potential for further research in this domain.

Research paper thumbnail of Autopsy investigation and Bayesian approach to coronary artery disease in victims of motor-vehicle accidents

Atherosclerosis, 2011

Each year, 1.2 million people die worldwide as a result of motor-vehicle accidents (MVA), represe... more Each year, 1.2 million people die worldwide as a result of motor-vehicle accidents (MVA), representing a tremendous burden to healthcare. The aim of this study was to define the prevalence of coronary disease and its possible role in motor-vehicle accidents. We examined consecutive cases of non-hospital sudden death autopsies in the area of West Quebec during the period of 2002-2006, and we focused on those victims of MVA. Severe coronary artery disease (CAD) was defined as a narrowing of ≥ 75% of a cross-sectional area or the presence of acute plaque events in major epicardial coronary arteries. From a total cohort of 1260 autopsies, MVA were responsible for 123 deaths, 100 of whom were men and 23 were women. Significant CAD was documented in approximately 37% of these cases. In individuals older than 60 years, the prevalence of significant CAD and ischemia were 86.2% and 19.8%, respectively. A percentage of 40% of the coronary patients showed erratic driving before the accident, as observed by witnesses. Statistical analysis showed that an individual affected by CAD has 9% probability of suffering a motor-vehicle accident. The prevalence of severe CAD and acute myocardial ischemia is very high among individuals who have suffered a MVA. Our data suggest the hypothesis that acute CAD could be the cause of accidents in a large group of the drivers affected by coronary disease. For these reasons CAD could be investigated in drivers above 50 years old, as a possible preventive measure and determinant of individual risk stratification.

Research paper thumbnail of Wrapper discretization by means of estimation of distribution algorithms

ABSTRACT We present a supervised wrapper approach to discretization. In contrast to many classica... more ABSTRACT We present a supervised wrapper approach to discretization. In contrast to many classical approaches, the discretization process is multivariate: all variables are discretized simultaneously, and the proposed discretization is evaluated with the Naive-Bayes classifier. The search for the optimal discretization is carried out as an optimization process with the learning model estimated accuracy guiding it. The global optimization algorithm is based on estimation of distribution algorithms, a set of novel algorithms which are special kinds of evolutionary algorithms. In order to evaluate the behaviour of the algorithm, an analysis of different parameters is performed by means of analysis of variance (ANOVA). The evaluation was carried out using artificial datasets, and with UCI datasets. The results suggest that the proposed method provides an effective and robust technique for discretizating variables.

Research paper thumbnail of Increase in sudden death from coronary artery disease in young adults

American Heart Journal, 2011

Sudden cardiac death (SCD) is the most common cause of death in adults aged &amp;amp;amp;amp;... more Sudden cardiac death (SCD) is the most common cause of death in adults aged &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;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;65 years, making it a major public health problem. A growing incidence in coronary artery disease (CAD) in young individuals has been predicted in developed countries, which could in turn be associated with an increase in SCD in this population. The aim of the study was to assess the prevalence of CAD among autopsies of young individuals (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;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;40 years) who had sudden death (SD). We selected all the autopsies referred to the Montreal Heart Institute and Maisonneuve-Rosemont Hospital from January 2002 to December 2006 that corresponded to individuals &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;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;40 years old who had died suddenly. For each decedent, the following data were collected: cause of death, autopsy findings, available clinical history, toxicological findings, and cardiovascular risk factors. From a total of 1,260 autopsies, 243 fulfilled the inclusion criteria. Coronary artery disease was the main cause of SCD from age 20 years, representing the 37% of deaths in the group of 21 to 30 years old, and up to 80% of deaths in the group of 31 to 40 years old. Among individuals who died of CAD, 3-vessel disease was observed in 39.7% of cases. Moreover, among the whole population &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;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;40 years old, at least 1 significant coronary lesion was observed in 39.5% of cases, irrespective to the cause of death. In the multivariable analysis, an increased BMI (hazard ratio 1.1 for each kg/m(2), 95% CI 1.01-1.1) and hypercholesterolemia (hazard ratio 2.4, 95% CI 1.7-333.3) showed to be the modifiable factors related to an increased risk of SD from CAD. In our population, CAD was the main cause of SD from age 20 years. These data bring into question whether present prevention strategies are sufficient and reinforce the need to extend prevention to younger ages.

Research paper thumbnail of Dynamical complexities in the Leslie-Gower predator-prey model as consequences of the Allee effect on prey

This work deals with the analysis of a predator–prey model derived from the Leslie–Gower type mod... more This work deals with the analysis of a predator–prey model derived from the Leslie–Gower type model, where the most common mathematical form to express the Allee effect in the prey growth function is considered. It is well-known that the Leslie–Gower model has a ...

Research paper thumbnail of Pleistocene fluctuations in the Agulhas Current Retroflection based on the calcareous plankton record

Piston core (PS2487-6), recovered south of Cape Town, and sediment surface samples, recovered in ... more Piston core (PS2487-6), recovered south of Cape Town, and sediment surface samples, recovered in the area of the Agulhas Current retroflection, were used to construct paleoceanographic scenarios for the late Quaternary in a region with an important role in global water mass transfer. Coccolithophore (calcareous nannofossil) and planktonic foraminifera assemblages and oxygen isotope data were collected. Stratigraphic control is based

Research paper thumbnail of Nuevas Aportaciones a La Biogeografía De Cocolitóforos En El Pacífico Ecuatorial Y Suroriental

Research paper thumbnail of Geological record and reconstruction of the late Pliocene impact of the Eltanin asteroid in the Southern Ocean

In 1995, an expedition on board the research vessel FS Polarstern explored the impact site of the... more In 1995, an expedition on board the research vessel FS Polarstern explored the impact site of the Eltanin asteroid in the Southern Ocean, the only known asteroid impact into a deep ocean basin. Analyses of the geological record of the impact region place the event in the late Pliocene (ϳ2.15 Myr) and constrain the size of the asteroid to be Ͼ1 km. The explosive force inferred for this event places it at the threshold of impacts believed to have global consequences, and its study should therefore provide a baseline for the reconstruction and modelling of similar events, which are common on geological timescales.

Research paper thumbnail of SNAP23 Is Selectively Expressed in Airway Secretory Cells and Mediates Baseline and Stimulated Mucin Secretion

Bioscience Reports, 2015

Airway mucin secretion is important pathophysiologically and as a model of polarized epithelial r... more Airway mucin secretion is important pathophysiologically and as a model of polarized epithelial regulated exocytosis. We find the trafficking protein, SNAP23 (23-kDa paralogue of synaptosome-associated protein of 25 kDa), selectively expressed in secretory cells compared with ciliated and basal cells of airway epithelium by immunohistochemistry and FACS, suggesting that SNAP23 functions in regulated but not constitutive epithelial secretion. Heterozygous SNAP23 deletant mutant mice show spontaneous accumulation of intracellular mucin, indicating a defect in baseline secretion. However mucins are released from perfused tracheas of mutant and wild-type (WT) mice at the same rate, suggesting that increased intracellular stores balance reduced release efficiency to yield a fully compensated baseline steady state. In contrast, acute stimulated release of intracellular mucin from mutant mice is impaired whether measured by a static imaging assay 5 min after exposure to the secretagogue ATP or by kinetic analysis of mucins released from perfused tracheas during the first 10 min of ATP exposure. Together, these data indicate that increased intracellular stores cannot fully compensate for the defect in release efficiency during intense stimulation. The lungs of mutant mice develop normally and clear bacteria and instilled polystyrene beads comparable to WT mice, consistent with these functions depending on baseline secretion that is fully compensated.

Research paper thumbnail of Evaluation of the time of uncapping and removing dead brood from cells by hygienic and non-hygienic honey bees

Genetics and molecular research : GMR, 2005

Most research on hygienic behavior has recorded the time taken by the colony to remove an experim... more Most research on hygienic behavior has recorded the time taken by the colony to remove an experimental amount of dead brood, usually after one or two days. We evaluated the time that hygienic (H) and non-hygienic (NH) honey bees take to uncap and remove dead brood in observation hives after the brood was killed using the pin-killing assay. Four experimental colonies were selected as the extreme cases among 108 original colonies. Thirty brood cells were perforated with a pin in two H and two NH colonies and observations were made after 1, 2, 3, 4, 5, 6, and 24 h. Different stages of uncapping and removing were recorded. Differences in uncapping and removal between H and NH colonies were significant for all comparisons made at the different times after perforation. Using observation hives one obtains a better and faster discrimination between H and NH colonies than in full size colonies. It is possible to differentiate H and NH within a few hours after perforating the cells.

Research paper thumbnail of Structure and dynamics of pollination networks: the role of alien plants

Oikos, 2009

Research on ecological communities, and plantÁpollinator mutualistic networks in particular, has ... more Research on ecological communities, and plantÁpollinator mutualistic networks in particular, has increasingly benefited from the theory and tools of complexity science. Nevertheless, up to now there have been few attempts to investigate the interplay between the structure of real pollination networks and their dynamics. This study is one of the first contributions to explore this issue. Biological invasions, of major concern for conservation, are also poorly understood from the perspective of complex ecological networks. In this paper we assess the role that established alien species play within a host community by analyzing the temporal changes in structural network properties driven by the removal of non-native plants. Three topological measures have been used to represent the most relevant structural properties for the stability of ecological networks: degree distribution, nestedness, and modularity. Therefore, we investigate for a detailed pollination network, 1) how its dynamics, represented as changes in species abundances, affect the evolution of its structure, 2) how topology relates to dynamics focusing on long-term species persistence; and 3) how both structure and dynamics are affected by the removal of alien plant species. Network dynamics were simulated by means of a stochastic metacommunity model. Our results showed that established alien plants are important for the persistence of the pollination network and for the maintenance of its structure. Removal of alien plants decreased the likelihood of species persistence. On the other hand, both the full network and the subset native network tended to lose their structure through time. Nevertheless, the structure of the full network was better preserved than the structure of the network without alien plants. Temporal topological shifts were evident in terms of degree distribution, nestedness, and modularity. However the effects of removing alien plants were more pronounced for degree distribution and modularity of the network. Therefore, elimination of alien plants affected the evolution of the architecture of the interaction web, which was closely related to the higher species loss found in the network where alien plants were removed.

Research paper thumbnail of The duration of the motor response to apomorphine boluses is conditioned by the length of a prior infusion in Parkinson's disease

Movement Disorders, 2009

&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;... more &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;Pulsatile&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; administration of levodopa has been invocated a relevant factor for motor fluctuations in Parkinson&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;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;s disease (PD). We studied dopaminergic sensitivity to apomorphine in 10 parkinsonian patients with motor fluctuations. Patients were tested as follows: the minimal effective dose of apomorphine (MED-1) was administered in the morning to induce an on response. Fifteen minutes after this motor response had disappeared, an apomorphine infusion was initiated and maintained to ensure on periods of three different durations on different days. Infusion lasted for approximately 30, 60 and 90 minutes. Subsequently, the infusion was stopped, and after 15 minutes in the off state, a second bolus of apomorphine (MED-2) was given. The mean infusion doses were 49.2 +/- 5.4, 108.4 +/- 10.3, and 150 +/- 8.2 mg. These elicited on periods of 48.2 +/- 4.1, 110 +/- 4.5, and 195 +/- 3.8 minutes. The MED-2 elicited on responses with a duration of 30 +/- 4.5, 18.4 +/- 3.2, and 11.2 +/- 4.1 minutes. The duration of the on response induced by the apomorphine infusions correlated inversely (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;lt; 0.01) with the on induced by the MED-2 of apomorphine. Our findings indicate that a continuous dopaminergic stimulus may induce pharmacodynamic changes associated with tolerance in PD patients.

Research paper thumbnail of Enterotoxigenic Escherichia coli Heat-Labile Toxin Seroconversion in US Travelers to Mexico

Journal of Travel Medicine, 2008

Enterotoxigenic Escherichia coli (ETEC) is the most common bacterial pathogen isolated from trave... more Enterotoxigenic Escherichia coli (ETEC) is the most common bacterial pathogen isolated from travelers suffering of diarrhea. Exposure to heat-labile toxin (LT) produces a high rate of seroconversion. However, the role of LT-producing ETEC (LT-ETEC) as a cause of diarrhea is controversial. We conducted a cohort study in US students traveling to Mexico to assess the ETEC-LT seroconversion rate after natural exposure. Participants provided a serum sample on arrival and departure and a stool sample when ill. ETEC-LT immunoglobulin G antibodies were measured by enzyme-linked immunosorbent assay, and LT-ETEC were detected by means of polymerase chain reaction done on fecal DNA. A total of 422 participants with a mean age of 34.5 years were followed a mean of 19.9 days; 304 were females (72.0%), and 319 (75.6%) traveled during the summer months. In total, 177 individuals (41.9%) developed travelers&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;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; diarrhea and 33.9% had LT-ETEC identified in their stools. Among individuals having an LT-ETEC strain, 74% seroconverted compared to 11% of those not having diarrhea (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;lt; 0.0001). When analyzed with a logistic regression model, the odds of seroconversion were significantly reduced in participants not having LT-ETEC in their stool (odds ratio = 0.1, 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;lt; 0.0001) after adjusting for season, length of stay, age, gender, race, and ethnicity. In US young adults traveling to Mexico, ETEC-LT seroconversion reliably identifies individuals naturally exposed to ETEC and correlates with symptomatic illness, length and season of travel.

Research paper thumbnail of Measuring individual and cultural differences in implicit trait theories

Journal of Personality and Social Psychology, 2003

A new measure of implicit theories or beliefs regarding the traitedness versus contextuality of b... more A new measure of implicit theories or beliefs regarding the traitedness versus contextuality of behavior was developed and tested across cultures. In Studies 1 (N ϭ 266) and 2 (N ϭ 266), these implicit beliefs dimensions were reliably measured and replicated across U.S. college student samples and validity evidence was provided. In Study 3, their structure replicated well across an individualistic culture (the United States; N ϭ 249) and a collectivistic culture (Mexico; N ϭ 268). Implicit trait and contextual beliefs overlapped only modestly with implicit entity theory beliefs and were predicted by self-construals in ways that generally supported cultural psychology hypotheses. Implicit trait beliefs were fairly strongly endorsed in both cultures, suggesting that such beliefs may be universally held.

Research paper thumbnail of Seroprevalence of the enteroaggregative Escherichia coli virulence factor dispersin among USA travellers to Cuernavaca, Mexico: a pilot study

Journal of Medical Microbiology, 2008

This pilot study examined the change in the seroprevalence of the enteroaggregative Escherichia c... more This pilot study examined the change in the seroprevalence of the enteroaggregative Escherichia coli (EAEC) virulence factor dispersin in USA students during a short stay in Cuernavaca, Mexico, between June and August 2004. One hundred and ninety-five students provided paired serum samples -one on arrival to Mexico (pre-serum) and a second on departure from Mexico (post-serum) after a mean stay of 19 days. Serum samples were tested for IgG antibody to a recombinant purified dispersin protein by ELISA. For all travellers, with and without diarrhoea, the mean±SD pre-serum absorbance value (read at 450 and 570 nm) was 0.340±0.212 and the mean post-serum value was 0.513±0.316 (P,0.00001). Both travellers who developed diarrhoea and those who did not develop diarrhoea had an increase in IgG antibody to dispersin from the time of arrival to the time of departure from Cuernavaca (diarrhoea group 0.323±0.197 to 0.501±0.311, P,0.00001, and the asymptomatic group 0.354±0.224 to 0.525±0.321, P,0.00001). The pre-serum absorbance value (read at 450 and 570 nm) for IgG antibody to dispersin was not associated with protection against the development of diarrhoeal illness. These results indicate that USA travellers to Mexico show seroconversion for the EAEC virulence factor dispersin. Further studies are needed to characterize in more detail the host clinical and immunological responses to the dispersin protein.

Research paper thumbnail of PCR-Based Assay Using Occult Blood Detection Cards for Detection of Diarrheagenic Escherichia coli in Specimens from U.S. Travelers to Mexico with Acute Diarrhea

Journal of Clinical Microbiology, 2008

Large field studies of travelers' diarrhea for multiple destinations are limited by the need to p... more Large field studies of travelers' diarrhea for multiple destinations are limited by the need to perform stool cultures on site in a timely manner. A method for the collection, transport, and storage of fecal specimens that does not require immediate processing and refrigeration and that is stable for months would be advantageous. This study was designed to determine if enterotoxigenic Escherichia coli (ETEC) and enteroaggregative E. coli (EAEC) DNA could be identified from cards that were processed for the evaluation of fecal occult blood. U.S. students traveling to Mexico during 2005 to 2007 were monitored for the occurrence of diarrheal illness. When ill, students provided a stool specimen for culture and occult blood by the standard methods. Cards then were stored at room temperature prior to DNA extraction. Fecal PCR was performed to identify ETEC and EAEC in DNA extracted from stools and from occult blood cards. Significantly more EAEC cases were identified by PCR that was performed on DNA that was extracted from cards (49%) or from frozen feces (40%) than from culture methods that used HEp-2 adherence assays (13%) (P < 0.001). Similarly, more ETEC cases were detected from card DNA (38%) than from fecal DNA (30%) or by culture that was followed by hybridization (10%) (P < 0.001). The sensitivity and specificity of the card test were 75 and 62%, respectively, compared to those for EAEC by culture and were 50 and 63%, respectively, compared to those for ETEC. DNA extracted from fecal cards that was used for the detection of occult blood is of use in identifying diarrheagenic E. coli.

Research paper thumbnail of Modelling the management of fragmented forests: Is it possible to recover the original tree composition?

Forest Ecology and Management, 2008

In the fragmented Maulino forest (in Central Chile), differences in the relative frequencies of s... more In the fragmented Maulino forest (in Central Chile), differences in the relative frequencies of species between seedlings and mature trees are strong indicators of a changing replacement dynamics in the community. Stationary Markov chain models predict that the future tree composition such Maulino forest fragments will differ from that of continuous, intact forest. We found that the persistence probability was highest for Aristotelia chilensis and lowest for Nothofagus glauca. These two tree species are the most affected by fragmentation, and changes in their abundances appear to be the main drivers of the long-term change in stand composition. The aim of our study was to test if the management of just these two species would be sufficient to avoid long-term changes in the composition of forest fragments or would recover their composition toward a state more similar to the continuous forest. For this purpose, we constructed a Markov matrix model from published information, and calculated the future stable stand composition under different management simulations: (1) reduction of A. chilensis recruitment, (2) increased recruitment of N. glauca, and (3) a combined treatment. To evaluate the effectiveness of management treatments, the future composition of fragments was compared with the composition expected for continuous (i.e., undisturbed) Maulino forest. We performed a sensitivity analysis of the stable composition in order to assess the intensity of changes in the future composition driven by the treatments, and to determine to what extend the recruitment of other coexisting species contributes to changes in relative frequencies of A. chilensis and N. glauca.

Research paper thumbnail of Role of inducible defenses in the stability of a tritrophic system

Ecological Complexity, 2008

Inducible defenses are a form of phenotypic plasticity that potentially modify direct interaction... more Inducible defenses are a form of phenotypic plasticity that potentially modify direct interactions between various members of an ecological community, generating trait-mediated indirect effects. In this work, the hypothesis that inducible defenses increase the stability of tritrophic chains is tested, through the numerical analysis of a continuous-time model that discriminate between defenses affecting attack rate of predators, and defenses affecting

Research paper thumbnail of Consequences of double Allee effect on the number of limit cycles in a predator–prey model

Computers & Mathematics with Applications, 2011

The main goal of this work is to show a comparative analysis of simple continuous time predator–p... more The main goal of this work is to show a comparative analysis of simple continuous time predator–prey models considering the Allee effect affecting the prey population, also known as depensation in fisheries sciences. This phenomenon may be expressed by different ...

Research paper thumbnail of ALLEE EFFECT, EMIGRATION AND IMMIGRATION IN A CLASS OF PREDATOR-PREY MODELS

Biophysical Reviews and Letters, 2008

ALLEE EFFECT, EMIGRATION AND IMMIGRATION IN A CLASS OF PREDATOR-PREY MODELS∗EDUARDO GONZALEZ-OLIV... more ALLEE EFFECT, EMIGRATION AND IMMIGRATION IN A CLASS OF PREDATOR-PREY MODELS∗EDUARDO GONZALEZ-OLIVARES, JAIME MENA-LORCA HECTOR MENESES-ALCAY, BETSABE GONZALEZ-YANEZ Grupo Ecologıa Matematica, Instituto de Matematicas ...

Research paper thumbnail of A review of estimation of distribution algorithms in bioinformatics

BioData Mining, 2008

Evolutionary search algorithms have become an essential asset in the algorithmic toolbox for solv... more Evolutionary search algorithms have become an essential asset in the algorithmic toolbox for solving high-dimensional optimization problems in across a broad range of bioinformatics problems. Genetic algorithms, the most well-known and representative evolutionary search technique, have been the subject of the major part of such applications. Estimation of distribution algorithms (EDAs) offer a novel evolutionary paradigm that constitutes a natural and attractive alternative to genetic algorithms. They make use of a probabilistic model, learnt from the promising solutions, to guide the search process. In this paper, we set out a basic taxonomy of EDA techniques, underlining the nature and complexity of the probabilistic model of each EDA variant. We review a set of innovative works that make use of EDA techniques to solve challenging bioinformatics problems, emphasizing the EDA paradigm's potential for further research in this domain.

Research paper thumbnail of Autopsy investigation and Bayesian approach to coronary artery disease in victims of motor-vehicle accidents

Atherosclerosis, 2011

Each year, 1.2 million people die worldwide as a result of motor-vehicle accidents (MVA), represe... more Each year, 1.2 million people die worldwide as a result of motor-vehicle accidents (MVA), representing a tremendous burden to healthcare. The aim of this study was to define the prevalence of coronary disease and its possible role in motor-vehicle accidents. We examined consecutive cases of non-hospital sudden death autopsies in the area of West Quebec during the period of 2002-2006, and we focused on those victims of MVA. Severe coronary artery disease (CAD) was defined as a narrowing of ≥ 75% of a cross-sectional area or the presence of acute plaque events in major epicardial coronary arteries. From a total cohort of 1260 autopsies, MVA were responsible for 123 deaths, 100 of whom were men and 23 were women. Significant CAD was documented in approximately 37% of these cases. In individuals older than 60 years, the prevalence of significant CAD and ischemia were 86.2% and 19.8%, respectively. A percentage of 40% of the coronary patients showed erratic driving before the accident, as observed by witnesses. Statistical analysis showed that an individual affected by CAD has 9% probability of suffering a motor-vehicle accident. The prevalence of severe CAD and acute myocardial ischemia is very high among individuals who have suffered a MVA. Our data suggest the hypothesis that acute CAD could be the cause of accidents in a large group of the drivers affected by coronary disease. For these reasons CAD could be investigated in drivers above 50 years old, as a possible preventive measure and determinant of individual risk stratification.

Research paper thumbnail of Wrapper discretization by means of estimation of distribution algorithms

ABSTRACT We present a supervised wrapper approach to discretization. In contrast to many classica... more ABSTRACT We present a supervised wrapper approach to discretization. In contrast to many classical approaches, the discretization process is multivariate: all variables are discretized simultaneously, and the proposed discretization is evaluated with the Naive-Bayes classifier. The search for the optimal discretization is carried out as an optimization process with the learning model estimated accuracy guiding it. The global optimization algorithm is based on estimation of distribution algorithms, a set of novel algorithms which are special kinds of evolutionary algorithms. In order to evaluate the behaviour of the algorithm, an analysis of different parameters is performed by means of analysis of variance (ANOVA). The evaluation was carried out using artificial datasets, and with UCI datasets. The results suggest that the proposed method provides an effective and robust technique for discretizating variables.

Research paper thumbnail of Increase in sudden death from coronary artery disease in young adults

American Heart Journal, 2011

Sudden cardiac death (SCD) is the most common cause of death in adults aged &amp;amp;amp;amp;... more Sudden cardiac death (SCD) is the most common cause of death in adults aged &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;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;65 years, making it a major public health problem. A growing incidence in coronary artery disease (CAD) in young individuals has been predicted in developed countries, which could in turn be associated with an increase in SCD in this population. The aim of the study was to assess the prevalence of CAD among autopsies of young individuals (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;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;40 years) who had sudden death (SD). We selected all the autopsies referred to the Montreal Heart Institute and Maisonneuve-Rosemont Hospital from January 2002 to December 2006 that corresponded to individuals &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;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;40 years old who had died suddenly. For each decedent, the following data were collected: cause of death, autopsy findings, available clinical history, toxicological findings, and cardiovascular risk factors. From a total of 1,260 autopsies, 243 fulfilled the inclusion criteria. Coronary artery disease was the main cause of SCD from age 20 years, representing the 37% of deaths in the group of 21 to 30 years old, and up to 80% of deaths in the group of 31 to 40 years old. Among individuals who died of CAD, 3-vessel disease was observed in 39.7% of cases. Moreover, among the whole population &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;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;40 years old, at least 1 significant coronary lesion was observed in 39.5% of cases, irrespective to the cause of death. In the multivariable analysis, an increased BMI (hazard ratio 1.1 for each kg/m(2), 95% CI 1.01-1.1) and hypercholesterolemia (hazard ratio 2.4, 95% CI 1.7-333.3) showed to be the modifiable factors related to an increased risk of SD from CAD. In our population, CAD was the main cause of SD from age 20 years. These data bring into question whether present prevention strategies are sufficient and reinforce the need to extend prevention to younger ages.

Research paper thumbnail of Dynamical complexities in the Leslie-Gower predator-prey model as consequences of the Allee effect on prey

This work deals with the analysis of a predator–prey model derived from the Leslie–Gower type mod... more This work deals with the analysis of a predator–prey model derived from the Leslie–Gower type model, where the most common mathematical form to express the Allee effect in the prey growth function is considered. It is well-known that the Leslie–Gower model has a ...

Research paper thumbnail of Pleistocene fluctuations in the Agulhas Current Retroflection based on the calcareous plankton record

Piston core (PS2487-6), recovered south of Cape Town, and sediment surface samples, recovered in ... more Piston core (PS2487-6), recovered south of Cape Town, and sediment surface samples, recovered in the area of the Agulhas Current retroflection, were used to construct paleoceanographic scenarios for the late Quaternary in a region with an important role in global water mass transfer. Coccolithophore (calcareous nannofossil) and planktonic foraminifera assemblages and oxygen isotope data were collected. Stratigraphic control is based