Relaciones filogenéticas y procesos evolutivos del género "Astyanax" Baird & Girard, 1854 (Teleostei, Characiformes) en Mesoamérica

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Biológicas, Departamento de Zoología y Antropología Física, leída el 24/01/2011.Depto. de Genética, Fisiología y MicrobiologíaFac. de Ciencias BiológicasTRUEProQuestpu

Evolutionary history of the fish genus Astyanax Baird & Girard (1854) (Actinopterygii, Characidae) in Mesoamerica reveals multiple morphological homoplasies

<p>Abstract</p> <p>Background</p> <p>Mesoamerica is one of the world's most complex biogeographical regions, mostly due to its complex geological history. This complexity has led to interesting biogeographical processes that have resulted in the current diversity and distribution of fauna in the region. The fish genus <it>Astyanax </it>represents a useful model to assess biogeographical hypotheses due to it being one of the most diverse and widely distributed freshwater fish species in the New World. We used mitochondrial and nuclear DNA to evaluate phylogenetic relationships within the genus in Mesoamerica, and to develop historical biogeographical hypotheses to explain its current distribution.</p> <p>Results</p> <p>Analysis of the entire mitochondrial cytochrome <it>b </it>(<it>Cytb</it>) gene in 208 individuals from 147 localities and of a subset of individuals for three mitochondrial genes (<it>Cytb</it>, 16 S, and <it>COI</it>) and a single nuclear gene (<it>RAG1</it>) yielded similar topologies, recovering six major groups with significant phylogeographic structure. Populations from North America and Upper Central America formed a monophyletic group, while Middle Central America showed evidence of rapid radiation with incompletely resolved relationships. Lower Central America lineages showed a fragmented structure, with geographically restricted taxa showing high levels of molecular divergence. All <it>Bramocharax </it>samples grouped with their sympatric <it>Astyanax </it>lineages (in some cases even with allopatric <it>Astyanax </it>populations), with less than 1% divergence between them. These results suggest a homoplasic nature to the trophic specializations associated with <it>Bramocharax </it>ecomorphs, which seem to have arisen independently in different <it>Astyanax </it>lineages. We observed higher taxonomic diversity compared to previous phylogenetic studies of the <it>Astyanax </it>genus. Colonization of Mesoamerica by <it>Astyanax </it>before the final closure of the Isthmus of Panama (3.3 Mya) explains the deep level of divergence detected in Lower Central America. The colonization of Upper Mesoamerica apparently occurred by two independent routes, with lineage turnover over a large part of the region.</p> <p>Conclusion</p> <p>Our results support multiple, independent origins of morphological traits in <it>Astyanax</it>, whereby the morphotype associated with <it>Bramocharax </it>represents a recurrent trophic adaptation. Molecular clock estimates indicate that <it>Astyanax </it>was present in Mesoamerica during the Miocene (~8 Mya), which implies the existence of an incipient land-bridge connecting South America and Central America before the final closure of the Isthmus of Panama (~3.3 Mya).</p

First record of a freshwater cave sponge (Porifera, unknown gen. and sp.) in a cave inhabited by Astyanax cavefish in the Sierra de El Abra, San Luis Potosí, Mexico

The karstic cave, la Cueva de Los Sabinos, located in the Sierra de El Abra in the state of San Luis Potosí, Mexico, is mostly known for hosting a population of blind, depigmented Astyanax mexicanus cavefish. Herein, we report the discovery of a non-pigmented sponge (Porifera) in the final sump of this cave. No genus or species name could be attributed because we did not collect any specimen. Up to now, the sponge distribution seems restricted to a single pool in la Cueva de Los Sabinos, but further careful exploration of other pools of the cave as well as closely related cavities is warranted. To our knowledge, this observation constitutes the fourth report of a freshwater, white, cave-adapted sponge in the world and the first for Mexico and North America. It is also the eleventh troglobite species encountered in Los Sabinos. Our discovery confirms the exceptionally rich biodiversity of this cave ecosystem

Modelo explicativo y predictivo de la ideación suicida en una muestra de bachilleres mexicanos

 La presente investigación se planteó como objetivo principal elaborar un modelo explicativo y predictivo de ideación suicida en estudiantes de un bachillerato mexicano. Los participantes del estudio fueron estudiantes de tres carreras técnicas de una institución de educación pública del estado de Jalisco, México. La muestra estuvo compuesta por 911 alumnos, seleccionados a través de un muestreo no probabilístico.  Las variables exógenas que fueron contempladas fueron el sexo, la práctica deportiva, horas de sueño, el apoyo familiar social percibido, el ajuste y victimización escolar, la conducta alimentaria de riesgo, la insatisfacción con la imagen corporal y la depresión. El instrumento para medir la ideación suicida fue la Escala de Ideación Suicida desarrollada por Beck, Kovacs y Weissman la cual mide las diversas características y frecuencia de pensamientos y actitudes referentes a la intencionalidad de cometer suicidio. Mediante un análisis de Regresión Lineal Múltiple se construyó un modelo explicativo y predictivo de ideación suicida que incluyó a las variables de depresión, apoyo familiar y problemas de ajuste a la escuela. A partir de los hallazgos se sugiere desarrollar estrategias de intervención dentro del contexto escolar y familiar que se enfoquen de manera primordial a las variables que predicen un aumento significativo de la ideación suicida.

Seminario de Economía Mexicana

Serie de ponencias referentes al Seminario de Economía Mexicana. Memorias del Seminario de Economía Mexicana de 199

Universidad y sociedad: la psicología aprendida mediante colaboraciones

Este material está dirigido tanto a investigadores como a profesores y estudiantes que tengan el interés de aprender nuevas formas de relacionarse para intervenir, en colaboración, en diferentes espacios sociales y realidades problemáticas. También puede resultar de interés para los directivos de instituciones públicas, privadas y organizaciones no gubernamentales que tengan a su cargo programas de intervención social, así como a luchadoras y luchadores sociales que busquen formas de organizarse para transformar situaciones particulares de vulnerabilidad. En estas páginas hay una invitación a formar universitarias y universitarios a partir de su intervención en problemáticas y escenarios vivos, a reconocer el saber colectivo de los otros que están insertos en diferentes situaciones y aprender que el conocimiento se genera a partir del vínculo y la colaboración con la diversidad.ITESO. A.C

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection