586 research outputs found

    Comparison of Harvested and Nonharvested Painted Turtle Populations

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    Painted turtles (Chrysemys picta) are commercially harvested in large numbers in Minnesota for sale to biological supply companies and the pet trade. We investigated the possible effects of this harvest by comparing size, demography, and catch rates of painted turtles in 12 harvested and 10 nonharvested painted turtle populations in 2001 and 2002. We correlated turtle catch rates to harvest status, and harvested lakes had a lower catch-per-unit-effort than nonharvested lakes. Harvest had minimal effect on the size of turtles captured, and we found no significant differences in the count of male:female:juvenile turtles among lakes of different harvest status. We suggest that painted turtle populations likely have been impacted by harvester activities, but it was unclear whether the current harvest is sustainable. Further work is needed to determine whether there are any long-term effects on painted turtle populations

    Sensor data to measure Hawthorne effects in cookstove evaluation.

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    This data in brief article includes estimated time cooking based on temperature sensor data taken every 30 min from three stone fires and introduced fuel-efficient Envirofit stoves in approximately 168 households in rural Uganda. These households were part of an impact evaluation study spanning about six months to understand the effects of fuel-efficient cookstoves on fuel use and pollution. Daily particulate matter (pollution) and fuelwood use data are also included. This data in brief file only includes the weeks prior to, during, and after an in-person measurement team visited each home. The data is used to analyze whether households change cooking patterns when in-person measurement teams are present versus when only the temperature sensor is in the home

    Tertiary Climate Change and the Diversification of the Amazonian Gecko Genus Gonatodes (Sphaerodactylidae, Squamata)

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    The genus Gonatodes is a monophyletic group of small-bodied, diurnal geckos distributed across northern South America, Central America, and the Caribbean. We used fragments of three nuclear genes (RAG2, ACM4, and c-mos) and one mitochondrial gene (16S) to estimate phylogenetic relationships among Amazonian species of Gonatodes. We used Penalized Likelihood to estimate timing of diversification in the genus. Most cladogenesis occurred in the Oligocene and early Miocene and coincided with a burst of diversification in other South American animal groups including mollusks, birds, and mammals. The Oligocene and early Miocene were periods dominated by dramatic climate change and Andean orogeny and we suggest that these factors drove the burst of cladogenesis in Gonatodes geckos as well as other taxa. A common pattern in Amazonian taxa is a biogeographic split between the eastern and western Amazon basin. We observed two clades with this spatial distribution, although large differences in timing of divergence between the east–west taxon pairs indicate that these divergences were not the result of a common vicariant event

    Species Limits and Phylogeography of North American Cricket Frogs (Acris: Hylidae)

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    Cricket frogs are widely distributed across the eastern United States and two species, the northern cricket frog (Acris crepitans) and the southern cricket frog (A. gryllus) are currently recognized. We generated a phylogenetic hypothesis for Acris using fragments of nuclear and mitochondrial genes in separate and combined phylogenetic analyses. We also used distance methods and fixation indices to evaluate species limits within the genus and the validity of currently recognized subspecies of A. crepitans. The distributions of existing A. crepitans subspecies, defined by morphology and call types, do not match the distributions of evolutionary lineages recovered using our genetic data. We discuss a scenario of call evolution to explain this disparity. We also recovered distinct phylogeographic groups within A. crepitans and A. gryllus that are congruent with other codistributed taxa. Under a lineage-based species concept, we recognize Acris blanchardi as a distinct species. The importance of this revised taxonomy is discussed in light of the dramatic declines in A. blanchardi across the northern and western portions of its range

    Coming to America: Multiple Origins of New World Geckos

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    Geckos in the Western Hemisphere provide an excellent model to study faunal assembly at a continental scale. We generated a time-calibrated phylogeny, including exemplars of all New World gecko genera, to produce a biogeographic scenario for the New World geckos. Patterns of New World gecko origins are consistent with almost every biogeographic scenario utilized by a terrestrial vertebrate with different New World lineages showing evidence of vicariance, dispersal via temporary land bridge, overseas dispersal, or anthropogenic introductions. We also recovered a strong relationship between clade age and species diversity, with older New World lineages having more species than more recently arrived lineages. Our data provide the first phylogenetic hypothesis for all New World geckos and highlight the intricate origins and ongoing organization of continental faunas. The phylogenetic and biogeographical hypotheses presented here provide an historical framework to further pursue research on the diversification and assembly of the New World herpetofauna

    More Than a Safety Net: Ethiopia\u27s Flagship Public Works Program Increases Tree Cover

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    More than one billion people worldwide receive cash or in-kind transfers from social protection programs. In low-income countries, these transfers are often conditioned on participation in labor-intensive public works to rehabilitate local infrastructure or natural resources. Despite their popularity, the environmental impacts of public works programs remain largely undocumented. We quantify the impact on tree cover of Ethiopia\u27s Productive Safety Net Program (PSNP), one of the world\u27s largest and longest-running public works programs, using satellite-based data of tree cover combined with difference-in-differences and inverse probability treatment weighting methodologies. We find that the PSNP increased tree cover by 3.8% between 2005 and 2019, with larger increases in less densely populated areas and on steep-sloped terrain. As increasing tree cover is considered an important strategy to mitigate global warming, our results suggest a win–win potential for social safety net programs with an environmental component

    Effect of 5'UTR introns on gene expression in Arabidopsis thaliana.

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    BACKGROUND: The majority of introns in gene transcripts are found within the coding sequences (CDSs). A small but significant fraction of introns are also found to reside within the untranslated regions (5'UTRs and 3'UTRs) of expressed sequences. Alignment of the whole genome and expressed sequence tags (ESTs) of the model plant Arabidopsis thaliana has identified introns residing in both coding and non-coding regions of the genome. RESULTS: A bioinformatic analysis revealed some interesting observations: (1) the density of introns in 5'UTRs is similar to that in CDSs but much higher than that in 3'UTRs; (2) the 5'UTR introns are preferentially located close to the initiating ATG codon; (3) introns in the 5'UTRs are, on average, longer than introns in the CDSs and 3'UTRs; and (4) 5'UTR introns have a different nucleotide composition to that of CDS and 3'UTR introns. Furthermore, we show that the 5'UTR intron of the A. thaliana EF1alpha-A3 gene affects the gene expression and the size of the 5'UTR intron influences the level of gene expression. CONCLUSION: Introns within the 5'UTR show specific features that distinguish them from introns that reside within the coding sequence and the 3'UTR. In the EF1alpha-A3 gene, the presence of a long intron in the 5'UTR is sufficient to enhance gene expression in plants in a size dependent manner

    The quest for greener pastures: evaluating the livelihoods impacts of providing vegetation condition maps to pastoralists in Eastern Africa

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    The survival of millions of pastoral households in Eastern Africa has become increasingly at risk. Due to mounting socioeconomic and climatic stressors, pastoral households are faced with making migration decisions under increasing uncertainty about resource availability and limited coping strategies. We assess the potential of providing vegetation condition maps to support the migration decision of pastoralists in Ethiopia and Tanzania and the effect of map usage on their herd condition and size. The maps were generated from remotely sensed data using the Normalized Difference Vegetation Index (NDVI) as a proxy for vegetation condition and overlain with pastoralists’ preferred grazing areas. The use of maps for migration decisions was low in both study areas, partly due to challenges in map distribution (26% and 2% in Ethiopia at midline and endline respectively; and 35% and 29% in Tanzania at midline and endline respectively). However, map adopters in both countries reported an overwhelmingly positive experience and found maps accurate and helpful. Map usage was associated with improved animal condition in Tanzania, but we find no causal evidence that map usage affected herd size

    D0-branes in Black Hole Attractors

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    Configurations of N probe D0-branes in a Calabi-Yau black hole are studied. A large degeneracy of near-horizon bound states are found which can be described as lowest Landau levels tiling the horizon of the black hole. These states preserve some of the enhanced supersymmetry of the near-horizon AdS_2xS^2xCY attractor geometry, but not of the full asymptotically flat solution. Supersymmetric non-abelian configurations are constructed which, via the Myers effect, develop charges associated with higher-dimensional branes wrapping CY cycles. An SU(1,1|2) superconformal quantum mechanics describing D0-branes in the attractor geometry is explicitly constructed.Comment: 27 page
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