60 resultados para Agricultural populations


Relevância:

20.00% 20.00%

Publicador:

Resumo:

There is a concern that agriculture will no longer be able to meet, on a global scale, the growing demand for food. Facing such a challenge requires new patterns of thinking in the context of complexity and sustainability sciences. This paper, focused on the social dimension of the study and management of agricultural systems, suggests that rethinking the study of agricultural systems entails analyzing them as complex socio-ecological systems, as well as considering the differing thinking patterns of diverse stakeholders. The intersubjective nature of knowledge, as studied by different philosophical schools, needs to be better integrated into the study and management of agricultural systems than it is done so far, forcing us to accept that there are no simplistic solutions, and to seek a better understanding of the social dimension of agriculture. Different agriculture related problems require different policy and institutional approaches. Finally, the intersubjective nature of knowledge asks for the visualization of different framings and the power relations taking place in the decision-making process. Rethinking management of agricultural systems implies that policy making should be shaped by different principles: learning, flexibility, adaptation, scale-matching, participation, diversity enhancement and precaution hold the promise to significantly improve current standard management procedures.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Crop seasonal sensitivity to water stress is concerned with how to control water stress levels to optimise yield or profitability. It deals with when we can reduce irrigation and impose moderate water deficits without affecting our target, and when we can apply water to avoid too much stress.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background: Differences in the distribution of genotypes between individuals of the same ethnicity are an important confounder factor commonly undervalued in typical association studies conducted in radiogenomics. Objective: To evaluate the genotypic distribution of SNPs in a wide set of Spanish prostate cancer patients for determine the homogeneity of the population and to disclose potential bias. Design, Setting, and Participants: A total of 601 prostate cancer patients from Andalusia, Basque Country, Canary and Catalonia were genotyped for 10 SNPs located in 6 different genes associated to DNA repair: XRCC1 (rs25487, rs25489, rs1799782), ERCC2 (rs13181), ERCC1 (rs11615), LIG4 (rs1805388, rs1805386), ATM (rs17503908, rs1800057) and P53 (rs1042522). The SNP genotyping was made in a Biotrove OpenArrayH NT Cycler. Outcome Measurements and Statistical Analysis: Comparisons of genotypic and allelic frequencies among populations, as well as haplotype analyses were determined using the web-based environment SNPator. Principal component analysis was made using the SnpMatrix and XSnpMatrix classes and methods implemented as an R package. Non-supervised hierarchical cluster of SNP was made using MultiExperiment Viewer. Results and Limitations: We observed that genotype distribution of 4 out 10 SNPs was statistically different among the studied populations, showing the greatest differences between Andalusia and Catalonia. These observations were confirmed in cluster analysis, principal component analysis and in the differential distribution of haplotypes among the populations. Because tumor characteristics have not been taken into account, it is possible that some polymorphisms may influence tumor characteristics in the same way that it may pose a risk factor for other disease characteristics. Conclusion: Differences in distribution of genotypes within different populations of the same ethnicity could be an important confounding factor responsible for the lack of validation of SNPs associated with radiation-induced toxicity, especially when extensive meta-analysis with subjects from different countries are carried out.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Different signatures of natural selection persist over varying time scales in our genome, revealing possible episodes of adaptative evolution during human history. Here, we identify genes showing signatures of ancestral positive selection in the human lineage and investigate whether some of those genes have been evolving adaptatively in extant human populations. Specifically, we compared more than 11,000 human genes with their orthologs inchimpanzee, mouse, rat and dog and applied a branch-site likelihood method to test for positive selection on the human lineage. Among the significant cases, a robust set of 11 genes were then further explored for signatures of recent positive selection using SNP data. We genotyped 223 SNPs in 39 worldwide populations from the HGDP Diversity panel and supplemented this information with available genotypes for up to 4,814 SNPs distributed along 2 Mb centered on each gene. After exploring the allele frequency spectrum, population differentiation and the maintainance of long unbroken haplotypes, we found signals of recent adaptative phenomena in only one of the 11 candidate gene regions. However, the signal ofrecent selection in this region may come from a different, neighbouring gene (CD5) ratherthan from the candidate gene itself (VPS37C). For this set of positively-selected genes in thehuman lineage, we find no indication that these genes maintained their rapid evolutionarypace among human populations. Based on these data, it therefore appears that adaptation forhuman-specific and for population-specific traits may have involved different genes.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Se describe la secuencia de cortejo y apareamiento de machos y hembras de Sesamia nonagrioides (Lefèbvre) en el laboratorio. Esta secuencia no varió en presencia o ausencia de plantas de maíz. Se estudió la capacidad de atracción de un sexo sobre el otro atando el individuo de un sexo y dejando libre al complementario. La secuencia de cortejo y apareo de las hembras atadas fue la misma que la de las no atadas, pero los machos atados permanecieron absolutamente inactivos. La edad de los adultos (1 día versus 2 días) no afectó al porcentaje de apareamiento. Se encontraron diferencias en la hora del inicio de la llamada de las hembras y en la edad de las hembras en la primera llamada entre la población estudiada y lo descrito para una población griega, diferencias que podrían estar relacionadas con el origen geográfico. Se discute el papel de los penachos abdominales de los machos en el vuelo de cortejo, rechazándose que estimulen el comportamiento de llamada de las hembras o que las atraigan. Cuando no se aplicaron feromonas, el porcentaje de apareamiento en el laboratorio o en el campo no varió cuando aumentó la densidad de la población. Sin embargo, en los campos en que se aplicó confusión sexual, el porcentaje de apareamiento aumentó al aumentar la densidad de adultos. En la discusión se aportan algunas consecuencias para la investigación de la composición de las feromonas y su uso para el seguimiento de plagas y el control mediante confusión sexual.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background: The use of emergency hospital services (EHS) has increased steadily in Spain in the last decade while the number of immigrants has increased dramatically. Studies show that immigrants use EHS differently than native-born individuals, and this work investigates demographics, diagnoses and utilization rates of EHS in Lleida (Spain). Methods: Cross-sectional study of all the 96,916 EHS visits by patients 15 to 64 years old, attended during the years 2004 and 2005 in a public teaching hospital. Demographic data, diagnoses of the EHS visits, frequency of hospital admissions, mortality and diagnoses at hospital discharge were obtained. Utilization rates were estimated by group of origin. Poisson regression was used to estimate the rate ratios of being visited in the EHS with respect to the Spanish-born population. Results: Immigrants from low-income countries use EHS services more than the Spanish-born population. Differences in utilization patterns are particularly marked for Maghrebi men and women and sub-Saharan women. Immigrant males are at lower risk of being admitted to the hospital, as compared with Spanish-born males. On the other hand, immigrant women are at higher risk of being admitted. After excluding the visits with gynecologic and obstetric diagnoses, women from sub-Saharan Africa and the Maghreb are still at a higher risk of being admitted than their Spanish-born counterparts. Conclusion: In Lleida (Spain), immigrants use more EHS than the Spanish born population. Future research should indicate whether the same pattern is found in other areas of Spain and whether EHS use is attributable to health needs, barriers to access to the primary care services or similarities in the way immigrants access health care in their countries of origin.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background: There are few studies comparing pharmaceutical costs and the use of medications between immigrants and the autochthonous population in Spain. The objective of this study is to evaluate whether there are differences in pharmaceutical consumption and expenses between immigrant and Spanish-born populations. Methods: Prospective observational study in 1,630 immigrants and 4,154 Spanish-born individuals visited by fifteen primary care physicians at five public Primary Care Clinics (PCC) during 2005 in the city of Lleida, Catalonia (Spain). Data on pharmaceutical consumption and expenses was obtained from a comprehensive computerized data-collection system. Multinomial regression models were used to estimate relative risks and confidence intervals of pharmaceutical expenditure, adjusting for age and sex. Results: The percentage of individuals that purchased medications during a six-month period was 53.7% in the immigrant group and 79.2% in the autochthonous group. Pharmaceutical expenses and consumption were lower in immigrants than in autochthonous patients in all age groups and both genders. The relative risks of being in the highest quartile of expenditure, for Spanish-born versus immigrants, were 6.9, 95% CI = (4.2, 11.5) in men and 5.3, 95% CI = (3.5, 8.0) in women, with the reference category being not having any pharmaceutical expenditure. Conclusion: Pharmaceutical expenses are much lower for immigrants with respect to autochthonous patients, both in the percentage of prescriptions filled at pharmacies and the number of containers of medication obtained, as well as the prices of the medications used. Future studies should explore which factors explain the observed differences in pharmaceutical expenses and if these disparities produce health inequalities.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

BACKGROUND: Health professionals and organizations in developed countries adapt slowly to the increase of ethnically diverse populations attending health care centres. Several studies report that attention to immigrant mental health comes up with barriers in access, diagnosis and therapeutics, threatening equity. This study analyzes differences in exposure to antidepressant drugs between the immigrant and the native population of a Spanish health region. METHODS: Cross-sectional study of the dispensation of antidepressant drugs to the population aged 15 years or older attending the public primary health centres of a health region, 232,717 autochthonous and 33,361 immigrants, during 2008. Data were obtained from computerized medical records and pharmaceutical records of medications dispensed in pharmacies. Age, sex, country of origin, visits, date of entry in the regional health system, generic drugs and active ingredients were considered. Statistical analysis expressed the percentage of persons exposed to antidepressants stratified by age, gender, and country of origin and prevalence ratios of antidepressant exposition were calculated. RESULTS: Antidepressants were dispensed to 11% of native population and 2.6% of immigrants. Depending on age, native women were prescribed antidepressants between 1.9 and 2.7 times more than immigrant women, and native men 2.5 and 3.1 times more than their immigrant counterparts. Among immigrant females, the highest rate was found in the Latin Americans (6.6%) and the lowest in the sub-Saharans (1.4%). Among males, the highest use was also found in the Latin Americans (1.6%) and the lowest in the sub-Saharans (0.7%). The percentage of immigrants prescribed antidepressants increased significantly in relation to the number of years registered with the local health system. Significant differences were found for the new antidepressants, prescribed 8% more in the native population than in immigrants, both in men and in women. CONCLUSIONS: All the immigrants, regardless of the country of origin, had lower antidepressant consumption than the native population of the same age and sex. Latin American women presented the highest levels of consumption, and the sub-Saharan men the lowest. The prescription profiles also differed, since immigrants consumed more generics and fewer recently commercialized active ingredients.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Further genetic gains in wheat yield are required to match expected increases in demand. This may require the identification of physiological attributes able to produce such improvement, as well as the genetic bases controlling those traits in order to facilitate their manipulation. In the present paper, a theoretical framework of source and sink limitation to wheat yield is presented and the fine-tuning of crop development as an alternative for increasing yield potential is discussed. Following a top-down approach, most crop physiologists have agreed that the main attribute explaining past genetic gains in yield was harvest index (HI). By virtue of previous success, no further gains may be expected in HI and an alternative must be found. Using a bottom-up approach, the present paper firstly provides evidence on the generalized sink-limited condition of grain growth, determining that for further increases in yield potential, sink strength during grain filling has to be increased. The focus should be on further increasing grain number per m2, through fine-tuning pre-anthesis developmental patterns. The phase of rapid spike growth period (RSGP) is critical for grain number determination and increasing spike growth during pre-anthesis would result in an increased number of grains. This might be achieved by lengthening the duration of the phase (though without altering flowering time), as there is genotypic variation in the proportion of pre-anthesis time elapsed either before or after the onset of the stem elongation phase. Photoperiod sensitivity during RSGP could be then used as a genetic tool to further increase grain number, since slower development results in smoother floret development and more floret primordia achieve the fertile floret stage, able to produce a grain. Far less progress has been achieved on the genetic control of this attribute. None of the well-known major Ppd alleles seems to be consistently responsible for RSGP sensitivity. Alternatives for identifying the genetic factors responsible for this sensitivity (e.g. quantitative trait locus (QTL) identification in mapping populations) are being considered.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background: The reduction in the amount of food available for European avian scavengers as a consequence of restrictive public health policies is a concern for managers and conservationists. Since 2002, the application of several sanitary regulations has limited the availability of feeding resources provided by domestic carcasses, but theoretical studies assessing whether the availability of food resources provided by wild ungulates are enough to cover energetic requirements are lacking. Methodology/Findings: We assessed food provided by a wild ungulate population in two areas of NE Spain inhabited by three vulture species and developed a P System computational model to assess the effects of the carrion resources provided on their population dynamics. We compared the real population trend with to a hypothetical scenario in which only food provided by wild ungulates was available. Simulation testing of the model suggests that wild ungulates constitute an important food resource in the Pyrenees and the vulture population inhabiting this area could grow if only the food provided by wild ungulates would be available. On the contrary, in the Pre-Pyrenees there is insufficient food to cover the energy requirements of avian scavenger guilds, declining sharply if biomass from domestic animals would not be available. Conclusions/Significance: Our results suggest that public health legislation can modify scavenger population trends if a large number of domestic ungulate carcasses disappear from the mountains. In this case, food provided by wild ungulates could be not enough and supplementary feeding could be necessary if other alternative food resources are not available (i.e. the reintroduction of wild ungulates), preferably in European Mediterranean scenarios sharing similar and socio-economic conditions where there are low densities of wild ungulates. Managers should anticipate the conservation actions required by assessing food availability and the possible scenarios in order to make the most suitable decisions.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background: Non-compliance with antidepressant treatment continues to be a complex problem in mental health care. In immigrant populations non-compliance is one of several barriers to adequate management of mental illness; some data suggest greater difficulties in adhering to pharmacological treatment in these groups and an increased risk of therapeutic failure. The aim of this study is to assess differences in the duration and compliance with antidepressant treatment among immigrants and natives in a Spanish health region. Methods: Population-based (n = 206,603), retrospective cohort study including all subjects prescribed ADT between 2007 and 2009 and recorded in the national pharmacy claims database. Compliance was considered adequate when the duration was longer than 4 months and when patients withdrew more than 80% of the packs required. Results: 5334 subjects (8.5% of them being immigrants) initiated ADT. Half of the immigrants abandoned treatment during the second month (median for natives = 3 months). Of the immigrants who continued, only 29.5% presented good compliance (compared with 38.8% in natives). The estimated risk of abandoning/ending treatment in the immigrant group compared with the native group, adjusted for age and sex, was 1.28 (95%CI 1.16-1.42). Conclusions: In the region under study, immigrants of all origins present higher percentages of early discontinuation of ADT and lower median treatment durations than the native population. Although this is a complex, multifactor situation, the finding of differences between natives and immigrants in the same region suggests the need to investigate the causes in greater depth and to introduce new strategies and interventions in this population group.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Cooperatives are the basis of the social economy in many agricultural sectors. The present research work investigates the management situation of the olive oil cooperatives in Catalonia. The study identifies a typology of cooperatives based on their attitudes towards to the sector. A positioning map of the different types of cooperatives is then established on the basis of their characteristics. The study concludes with important managerial aspects of olive oil cooperatives in Catalonia.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Since 2001 several outbreaks of a new disease associated with Border disease virus (BDV) infection have caused important declines in Pyrenean chamois (Rupicapra pyrenaica) populations in the Pyrenees. The goal of this study was to analyze the post-outbreak BDV epidemiology in the first two areas affected by disease with the aim to establish if the infection has become endemic. We also investigated if BDV infected wild and domestic ruminants sharing habitat with chamois. Unexpectedly, we found different epidemiological scenarios in each population. Since the disease outbreaks, some chamois populations recuperated quickly, while others did not recover as expected. In chamois from the first areas, prevalence was high (73.47%) and constant throughout the whole study period and did not differ between chamois born before and after the BDV outbreak; in all, BDV was detected by RT-PCR in six chamois. In the other areas, prevalence was lower (52.79%) and decreased during the study period; as well, prevalence was significantly lower in chamois born after the disease outbreak. No BDV were detected in this population. A comparative virus neutralisation test performed with four BDV strains and one Bovine viral diarrhoea virus (BVDV) strain showed that all the chamois had BDV-specific antibodies. Pestivirus antibodies were detected in all the rest of analyzed species, with low prevalence values in wild ruminants and moderate values in domestic ruminants. No viruses were detected in these species. These results confirm the hypothesis that outbreaks of BDV infection only affect the Pyrenean chamois, although other wild ruminants can occasionally be infected. In conclusion, two different scenarios have appeared since the first border disease outbreaks in Pyrenean chamois: on the one hand frequent BDV circulation with possible negative impact on population dynamics in some areas and on the other, lack of virus circulation and quick recovery of the chamois population.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

To study whether inversions (or arrangements) by themselves or karyotypes are the main global warming adaptive target of natural selection, two Drosophila subobscura Serbian populations (Apatin and Petnica) were re analyzed using different statistical approaches. Both populations were sampled in an approximately 15 years period: Apatin in 1994 and 2008 + 2009 and Petnica in 1995 and 2010. For all chromosomes, the four collections studied were in Hardy-Weinberg equilibrium. Thus, it seems that inversions (or arrangements) combined at random to constitute populations" karyotypes. However, there were differences in karyotypic fre quencies along the years, although they were significant only for Apatin population. It is possible to conclude that inversions (or arrangements) are likely the target of natural selection, because they presented long term changes, but combine at random to generate the corresponding karyotypic combinations. As a consequence, the frequencies of karyotypes also change along time.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Differences in health care utilization of immigrants 50 years of age and older relative to the native-born populations in eleven European countries are investigated. Negative binomial and zero-inflated Poisson regression are used to examine differences between immigrants and native-borns in number of doctor visits, visits to general practitioners, and hospital stays using the 2004 Survey of Health, Ageing, and Retirement in Europe database. In the pooled European sample and in some individual countries, older immigrants use from 13 to 20% more health services than native-borns after demographic characteristics are controlled. After controlling for the need for health care, differences between immigrants and native-borns in the use of physicians, but not hospitals, are reduced by about half. These are not changed much with the incorporation of indicators of socioeconomic status and extra insurance coverage. Higher country-level relative expenditures on health, paying physicians a fee-for-service, and physician density are associated with higher usage of physician services among immigrants.