16 research outputs found
Differential gene expression and morphological variation in tequila bats (Leptonycteris yerabauenae) :adaptations to migration
Patterns and Determinants of the Interstate Migration of Foreign-born and Native-born Mexicans in the United States, 2011-2015
Researchers at the Pew Research Center (PRC) have estimated that immigration will likely cause major changes in the United States distribution of the population, age and ethno/racial composition (2015). My dissertation examines the determinants of interstate U.S. migration for Mexicans who migrated between states during the years of 2011-2015. I analyzed the probability of unauthorized Mexicans to be interstate migrants during the same time period and examined whether punitive migration laws have an effect on the size of the migration streams of foreign born and native-born Mexicans in the U.S. Data from the American Community Surveys were used in both the macro and micro analyses of this dissertation. A proxy was used to estimate the unauthorized population in the micro analysis. Undocumented immigrants have a lower probability of interstate migration. Undocumented immigrants are not only socially, economically, and politically restrained but it appears that they are also physically trapped. For the macro analysis 49 contiguous states (and D.C.) were used, of the 2,352 interstate migrant streams that were identified only 1,317 were viable. The classic gravity model and human ecological model were used for the analysis of migration streams. If the destination state (j) was punitive, there was a positive association with the size of the interstate migration stream of Mexicans. There was not a relationship between punitive state at origin (i) and the size of the migration stream. The human ecological model provided a more sociologically comprehensive explanation of the volume of Mexican migration streams in comparison to the gravity model
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Population genetic structure and habitat connectivity for jaguar (Panthera onca) conservation in Central Belize
Background
Connectivity among jaguar (Panthera onca) populations will ensure natural gene flow and the long-term survival of the species throughout its range. Jaguar conservation efforts have focused primarily on connecting suitable habitat in a broad-scale. Accelerated habitat reduction, human-wildlife conflict, limited funding, and the complexity of jaguar behaviour have proven challenging to maintain connectivity between populations effectively. Here, we used non-invasive genetic sampling and individual-based conservation genetic analyses to assess genetic diversity and levels of genetic connectivity between individuals in the Cockscomb Basin Wildlife Sanctuary and the Maya Forest Corridor. We used expert knowledge and scientific literature to develop models of landscape permeability based on circuit theory with fine-scale landscape features as ecosystem types, distance to human settlements and roads to predict the most probable jaguar movement across central Belize.
Results
We used 12 highly polymorphic microsatellite loci to identify 50 individual jaguars. We detected high levels of genetic diversity across loci (HE = 0.61, HO = 0.55, and NA = 9.33). Using Bayesian clustering and multivariate models to assess gene flow and genetic structure, we identified one single group of jaguars (K = 1). We identified critical areas for jaguar movement that fall outside the boundaries of current protected areas in central Belize. We detected two main areas of high landscape permeability in a stretch of approximately 18 km between Sittee River Forest Reserve and Manatee Forest Reserve that may increase functional connectivity and facilitate jaguar dispersal from and to Cockscomb Basin Wildlife Sanctuary. Our analysis provides important insights on fine-scale genetic and landscape connectivity of jaguars in central Belize, an area of conservation concern.
Conclusions
The results of our study demonstrate high levels of relatively recent gene flow for jaguars between two study sites in central Belize. Our landscape analysis detected corridors of expected jaguar movement between the Cockscomb Basin Wildlife Sanctuary and the Maya Forest Corridor. We highlight the importance of maintaining already established corridors and consolidating new areas that further promote jaguar movement across suitable habitat beyond the boundaries of currently protected areas. Continued conservation efforts within identified corridors will further maintain and increase genetic connectivity in central Belize
High levels of population genetic differentiation in the American crocodile (Crocodylus acutus)
The American crocodile (Crocodylus acutus) is a widely distributed species across coastal and brackish areas of the Neotropical region of the Americas and the Greater Antilles. Available information on patterns of genetic differentiation in C. acutus shows a complex structuring influenced by interspecific interactions (mainly hybridization) and anthropogenic actions (mostly historical hunting, recent poaching, habitat loss and fragmentation, and unintentional translocation of individuals). In this study, we used data on mitochondrial DNA control region and 11 nuclear polymorphic microsatellite loci to assess the degree of population structure of C. acutus in South America, North America, Central America and the Greater Antilles. We used traditional genetic differentiation indices, Bayesian clustering and multivariate methods to create a more comprehensive picture of the genetic relationships within the species across its range. Analyses of mtDNA and microsatellite loci show evidence of a strong population genetic structure in the American crocodile, with unique populations in each sampling locality. Our results support previous findings showing large degrees of genetic differentiation between the continental and the Greater Antillean C. acutus. We report three new haplotypes unique to Venezuela, which are considerably less distant from the Central and North American haplotypes than to the Greater Antillean ones. Our findings reveal genetic population differentiation between Cuban and Jamaican C. acutus and offer the first evidence of strong genetic differentiation among the populations of Greater Antillean C. acutus
When Medicine Divorces Morality: The Effects Of Immigration Status On Health Care Access In The United States
This study highlights the importance of noting the heterogeneity of citizenship statuses among Latina/os when analyzing access to health care and health insurance attainment. A significant breakthrough in health care in the U.S. came on March 23, 2010 when President Barack Obama signed [H.R. 3590] The Patient Protection and Affordable Care Act (PPACA) legislating a universal health care system in the U S. While the passing of this legislation might have been a historical accomplishment it was not a panacea for all those suffering from lack of health insurance. The objectives of this study were three fold: 1) to analyze if citizenship status influences whether Latina/os have a usual place to visit for their health care needs, 2) to examine if citizenship status impacts the attainment of health insurance (private or public), and 3) to investigate the reasons why Latina/os lack health insurance. I utilized the Hispanics and Health Care in the United States: Access, Information and Knowledge survey collected by the Pew Hispanic Center from July 16 to September 23, 2007 for this study. Results show profoundly lower levels of health care access for non-citizen/ non-LPRs and LPRs in contrast to U.S. born Latina/os. Moreover, undocumented migrants reported their immigration status as the main barrier for not obtaining health insurance as opposed to health insurance being too expensive or it not being offered by their employer
Patterns and Determinants of the Interstate Migration of Foreign-born and Native-born Mexicans in the United States, 2011-2015
Researchers at the Pew Research Center (PRC) have estimated that immigration will likely cause major changes in the United States distribution of the population, age and ethno/racial composition (2015). My dissertation examines the determinants of interstate U.S. migration for Mexicans who migrated between states during the years of 2011-2015. I analyzed the probability of unauthorized Mexicans to be interstate migrants during the same time period and examined whether punitive migration laws have an effect on the size of the migration streams of foreign born and native-born Mexicans in the U.S. Data from the American Community Surveys were used in both the macro and micro analyses of this dissertation. A proxy was used to estimate the unauthorized population in the micro analysis. Undocumented immigrants have a lower probability of interstate migration. Undocumented immigrants are not only socially, economically, and politically restrained but it appears that they are also physically trapped. For the macro analysis 49 contiguous states (and D.C.) were used, of the 2,352 interstate migrant streams that were identified only 1,317 were viable. The classic gravity model and human ecological model were used for the analysis of migration streams. If the destination state (j) was punitive, there was a positive association with the size of the interstate migration stream of Mexicans. There was not a relationship between punitive state at origin (i) and the size of the migration stream. The human ecological model provided a more sociologically comprehensive explanation of the volume of Mexican migration streams in comparison to the gravity model
The Mexican Drug War and the Consequent Population Exodus: Transnational Movement at the U.S.-Mexican Border
At the frontline of México’s “war on drugs” is the Mexican-U.S. border city of Cd. Juárez, Chihuahua, which has become internationally known as the “murder capital of the world.” In Juárez, which neighbors El Paso, Texas, United States, estimates of the murders in Juárez are as high as 7,643 between 2006 and 2011, leaving approximately 10,000 orphans. Juárez has also experienced an exodus of approximately 124,000 people seeking safety, some migrating to the Mexican interior and others to the U.S., particularly along the U.S.-México border. Based on 63 in-depth interviews with Juárez-El Paso border residents, along with ethnographic observations, we examine the implications of the “war on drugs” on transnational movements and on the initial settlement of those escaping the violence. In particular, we construct a typology of international migrants who are represented in the Juárez exodus: the Mexican business elite, the “Refugees without Status,” and those who resided in México but who are U.S. born or have legal permanent residency in the U.S. This article highlights the role of transnational capital in the form of assets and income, social networks in the U.S., and documentation to cross the port of entry into the U.S. legally, in easing migration and initial settlement experiences in the U.S
Adult vampire bats produce contact calls when isolated: acoustic variation by species, population, colony, and individual.
BACKGROUND: Bat pups produce individually distinct isolation calls to facilitate maternal recognition. Increasing evidence suggests that, in group-living bat species, adults often use similar calls to maintain contact. We investigated if isolated adults from all three species of the highly cooperative vampire bats (Phyllostomidae: Desmodontinae) would produce vocally distinct contact calls when physically isolated. METHODS/PRINCIPAL FINDINGS: We assessed variation in contact calls recorded from isolated captive and wild-caught adult common vampire bats (Desmodus rotundus), white-winged vampire bats (Diaemus youngi) and hairy-legged vampire bats (Diphylla ecaudata). We compared species-typical contact call structure, and used information theory and permuted discriminate function analyses to examine call structure variation, and to determine if the individuality of contact calls is encoded by different call features across species and populations. We found that isolated adult vampire bats produce contact calls that vary by species, population, colony, and individual. However, much variation occurred within a single context and individual. We estimated signature information for captive Diaemus (same colony), captive Desmodus (same colony), and wild Desmodus (different colonies) at 3.21, 3.26, and 3.88 bits, respectively. Contact calls from a captive colony of Desmodus were less individually distinct than calls from wild-caught Desmodus from different colonies. Both the degree of individuality and parameters encoding individuality differed between the bats from a single captive colony and the wild-caught individuals from different groups. This result is consistent with, but not sufficient evidence of, vocal convergence in groups. CONCLUSION: Our results show that adult vampire bats of all three species produce highly variable contact calls when isolated. Contact calls contain sufficient information for vocal discrimination, but also possess more intra-individual variation than is required for the sole purpose of identifying individuals
Percentage of correctly assigning notes to four individuals for captive and wild common vampires <i>Desmodus rotundus</i> and captive white-winged vampires <i>Diaemus youngi</i>.
<p>Percentage of correctly assigning notes to four individuals for captive and wild common vampires <i>Desmodus rotundus</i> and captive white-winged vampires <i>Diaemus youngi</i>.</p
Acoustic variables used for discriminant function analyses.
<p>Acoustic variables used for discriminant function analyses.</p