Rosas-Guerrero V.,National Autonomous University of Mexico |
Rosas-Guerrero V.,Autonomous University of Guerrero |
Aguilar R.,National University of Cordoba |
Marten-Rodriguez S.,Institute Ecologia A C |
And 6 more authors.
Ecology Letters | Year: 2014
The idea of pollination syndromes has been largely discussed but no formal quantitative evaluation has yet been conducted across angiosperms. We present the first systematic review of pollination syndromes that quantitatively tests whether the most effective pollinators for a species can be inferred from suites of floral traits for 417 plant species. Our results support the syndrome concept, indicating that convergent floral evolution is driven by adaptation to the most effective pollinator group. The predictability of pollination syndromes is greater in pollinator-dependent species and in plants from tropical regions. Many plant species also have secondary pollinators that generally correspond to the ancestral pollinators documented in evolutionary studies. We discuss the utility and limitations of pollination syndromes and the role of secondary pollinators to understand floral ecology and evolution. Copyright © 2014 John Wiley & Sons Ltd/CNRS173 March 2014 10.1111/ele.12224 Review and Synthesis Review and Synthesis © 2014 John Wiley & Sons Ltd/CNRS.
Andersson N.,Autonomous University of Guerrero |
Cockcroft A.,CIET Trust Botswana
AIDS and Behavior | Year: 2012
Interpersonal power gradients may prevent people implementing HIV prevention decisions. Among 7,464 youth aged 15-29 years in Botswana, Namibia and Swaziland we documented indicators of choice-disability (low education, educational disparity with partner, experience of sexual violence, experience of intimate partner violence (IPV), poverty, partner income disparity, willingness to have sex without a condom despite believing partner at risk of HIV), and risk behaviours like inconsistent use of condoms and multiple partners. In Botswana, Namibia and Swaziland, 22.9, 9.1, and 26.1% women, and 8.3, 2.8, and 9.3% men, were HIV positive. Among both women and men, experience of IPV, IPV interacted with age, and partner income disparity interacted with age were associated with HIV positivity in multivariate analysis. Additional factors were low education (for women) and poverty (for men). Choice disability may be an important driver of the AIDS epidemic. New strategies are needed that favour the choice-disabled. © 2011 Springer Science+Business Media, LLC.
Ribera J.M.,Swiss Tropical and Public Health Institute |
Hausmann-Muela S.,Autonomous University of Guerrero
Medical Anthropology Quarterly | Year: 2011
In the wake of the Millennium Development Goals, the focus on vulnerability and access to care has increasingly gained ground in the malaria social science literature. However, little emphasis has been given to the cumulative processes of vulnerability. In this article, we draw on ethnographic data, in particular on case studies, gathered in southeastern Tanzania in the 1990s and reexamine them in the context of vulnerability. We analyze the underpinnings of the cumulative dimension of vulnerability at three levels: (1) structural, that is, elements that determine access to material and social resources; (2) agent driven, that is, the consequences of coping strategies that enhance vulnerability; and (3) conjunctural, that is, periods characterized by the confluence of adverse circumstances. We argue that the analysis of cumulative processes of vulnerability paints a more comprehensive picture of people's struggle for health. This opens up a more systemic and dynamic perspective on access to care for disadvantaged populations. © 2011 by the American Anthropological Association.
Vargas-De-Leon C.,Autonomous University of Guerrero |
Vargas-De-Leon C.,National Autonomous University of Mexico
Mathematical Biosciences and Engineering | Year: 2012
A delayed vector-bias model for malaria transmission with incubation period in mosquitoes is studied. The delay τ corresponds to the time necessary for a latently infected vector to become an infectious vector. We prove that the global stability is completely determined by the threshold parameter, ℛ0(τ). If ℛ0(τ) ≤ 1, the disease-free equilibrium is globally asymptotically stable. If ℛ0(τ) > 1 a unique endemic equilibrium exists and is globally asymptotically stable. We apply our results to Ross-MacDonald malaria models with an incubation period (extrinsic or intrinsic).
Martinez-Calleja A.,Autonomous University of Guerrero
Experimental diabetes research | Year: 2012
We evaluated the association between four polymorphisms in the CRP gene with circulating levels of C-reactive protein (CRP), type 2 diabetes (T2D), obesity, and risk score of coronary heart disease. We studied 402 individuals and classified them into four groups: healthy, obese, T2D obese, and T2D without obesity, from Guerrero, Southwestern Mexico. Blood levels of CRP, glucose, cholesterol, triglycerides, and leukocytes were measured. Genotyping was performed by PCR/RFLP, and the risk score for coronary heart disease was determined by the Framingham's methodology. The TT genotype of SNP rs1130864 was associated with increased body mass index and T2D patients with obesity. We found that the haplotype 2 (TGAG) was associated with increased levels of CRP (β = 0.3; 95%CI: 0.1, 0.5; P = 0.005) and haplotype 7 (TGGG) with higher body mass index (BMI) (β = 0.2; 95%CI: 0.1, 0.3; P < 0.001). The risk score for coronary heart disease was associated with increased levels of CRP, but not with any polymorphism or haplotype. The association between the TT genotype of SNP rs1130864 with obesity and the haplotype 7 with BMI may explain how obesity and genetic predisposition increase the risk of diseases such as T2D in the population of Southwestern Mexico.
Vargas-de-leoon C.,Autonomous University of Guerrero |
Korobeinikov A.,University of Limerick
Mathematical Medicine and Biology | Year: 2013
Reactions or interactions with the rate which is inhibited by the product or a by-product of the reaction are fairly common in biology and chemical kinetics. Biological examples of such interactions include selfpoisoning of bacteria, the non-lytic immune response and the antiviral (and in particular antiretroviral) therapy. As a case study, in this notice, we consider global asymptotic properties for a simple model with negative feedback (the Wodarz model) where the interaction is inhibited by a by-product of the reaction. The objective of this notice is an extending of a technique that was developed during last decade for the global analysis of models with positive feedback to the systems, where the feedback is negative. Using the direct Lyapunov method with Volterra type Lyapunov functions, we establish conditions for the global stability of this model. This result enables us to evaluate the comparative impacts of the lytic and nonlytic components, the efficiency of the antiviral therapy and the possibility of self-poisoning for bacteria. The same approach can be successfully applied to more complex models with negative feedback. © The Author 2011. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.
Espinoza-Rojo M.,Autonomous University of Guerrero
Central nervous system agents in medicinal chemistry | Year: 2010
Ischemic stroke is a major cause of death worldwide that provokes a high society cost. Deprivation of blood supply, with the subsequent deficiency of glucose and oxygen, triggers an important number of mechanisms (e.g. excitotoxicity, oxidative stress and inflammation) leading to irreversible neuronal injury. Consequently, ischemia increases the energy demand which is associated with profound changes in brain energy metabolism. Glucose transport activity may adapt to ensure the delivery of glucose to maintain normal cellular function, even at the low glucose levels observed in plasma during ischemia. In the brain, the main glucose transporters (GLUTs) are GLUT3 in neurons and GLUT1 in the microvascular endothelial cells of the blood brain barrier and glia. The intracellular signaling pathways involved in GLUT regulation in cerebral ischemia remain unclear; however, it has been established that ischemia induces changes in their expression. In this review, we describe the effect of glutamate-induced excitotoxicity, mitochondrial damage, glucose deprivation, and hypoxia on GLUTs expression in the brain. Additionally, we discuss the possible role of GLUTs as therapeutic target for ischemia. Despite of the intense research, current therapeutics options for stroke are very limited, therefore it is especially important to find new options. Few studies have examined the neuroprotective potential of GLUT up-regulation in ischemic stroke; however, evidence suggests that augmented GLUTs could be related to a protective mechanism. Increased understanding of the beneficial effects of GLUTs activation provides the rationale for targeting GLUT in the development of new therapeutic strategies.
Andersson N.,Autonomous University of Guerrero
AIDS care | Year: 2012
In efficacy trials male circumcision (MC) protected men against HIV infection. Planners need information relevant to MC programmes in practice. In 2008, we interviewed 2915 men and 4549 women aged 15-29 years in representative cluster samples in Botswana, Namibia and Swaziland, asking about socio-economic characteristics, knowledge and attitudes about HIV and MC and MC history. We tested finger prick blood samples for HIV. We calculated weighted frequencies of MC knowledge and attitudes, and MC history and HIV status. Multivariate analysis examined associations between MC and other variables and HIV status. In Botswana, 11% of young men reported MC, 28% in Namibia and 8% in Swaziland; mostly (75% in Botswana, 94% - mostly Herero - in Namibia and 68% in Swaziland) as infants or children. Overall, 6.5% were HIV positive (8.3% Botswana, 2.6% Namibia and 9.1% Swaziland). Taking other variables into account, circumcised men were as likely as uncircumcised men to be HIV positive. Nearly half of the uncircumcised young men planned to be circumcised; two-thirds of young men and women planned to have their sons circumcised. Some respondents had inaccurate beliefs and unhelpful views about MC and HIV, with variation between countries. Between 9 and 15% believed a circumcised man is fully protected against HIV; 20-26% believed men need not be tested for HIV before MC; 14-26% believed HIV-positive men who are circumcised cannot transmit the virus; and 8-34% thought it was "okay for a circumcised man to expect sex without a condom". Inaccurate perceptions about protection from MC could lead to risk compensation and reduce women's ability to negotiate safer sex. More efforts are needed to raise awareness about the limitations of MC protection, especially for women, and to study the interactions between MC roll out programmes and primary HIV prevention programmes.
Flores-Alfaro E.,Autonomous University of Guerrero
Genetics and molecular research : GMR | Year: 2012
Variants in the C-reactive protein (CRP) gene have been found to be associated with various phenotypic traits. We evaluated the effect of four SNPs in the CRP gene on serum levels of protein and body mass index (BMI) in 150 unrelated Mexican subjects from 18 to 25 years old, without hypertension, non-overweight, and without inflammatory diseases, non-smoking and non-consumers of alcohol. Subjects were measured for BMI, waist circumference, blood pressure, and serum glucose and triglycerides. The identification of SNPs was performed by PCR-RFLP. Three of the four SNPs were associated with variation in serum levels of CRP, increased in TT (rs1130864) and GG (rs2794521) genotypes, and decreased in the AA genotype of rs1205. The TT genotype was associated with a significant increase in BMI (β = 1.1 kg/m2, P = 0.04). Two haplotypes were significantly associated with increased serum levels of CRP, but not with BMI. We conclude that variation in the CRP gene affects serum protein levels.
Andersson N.,Autonomous University of Guerrero |
Lamothe G.,University of Ottawa
BMC Health Services Research | Year: 2011
Background: Focus groups, rapid assessment procedures, key informant interviews and institutional reviews of local health services provide valuable insights on health service resources and performance. A long-standing challenge of health planning is to combine this sort of qualitative evidence in a unified analysis with quantitative evidence from household surveys. A particular challenge in this regard is to take account of the neighbourhood or clustering effects, recognising that these can be informative or incidental. Methods. An example of food aid and food sufficiency from the Bosnian emergency (1995-96) illustrates two Lamothe cluster-adjustments of the Mantel Haenszel (MH) procedure, one assuming a fixed odds ratio and the other allowing for informative clustering by not assuming a fixed odds ratio. We compared these with conventional generalised estimating equations and a generalised linear mixed (GLMM) model, using a Laplace adjustment. Results: The MH adjustment assuming incidental clustering generated a final model very similar to GEE. The adjustment that does not assume a fixed odds ratio produced a final multivariate model and effect sizes very similar to GLMM. Discussion. In medium or large data sets with stratified last stage random sampling, the cluster adjusted MH is substantially more conservative than the nave MH computation. In the example of food aid in the Bosnian crisis, the cluster adjusted MH that does not assume a fixed odds ratio produced similar results to the GLMM, which identified informative clustering. © 2011 Andersson and Lamothe; licensee BioMed Central Ltd.