7,003 research outputs found
Landscape genetics reveal broad and fineâscale population structure due to landscape features and climate history in the northern leopard frog (Rana pipiens) in North Dakota
Prehistoric climate and landscape features play large roles structuring wildlife populations. The amphibians of the northern Great Plains of North America present an opportunity to investigate how these factors affect colonization, migration, and current population genetic structure. This study used 11 microsatellite loci to genotype 1,230 northern leopard frogs (Rana pipiens) from 41 wetlands (30 samples/wetland) across North Dakota. Genetic structure of the sampled frogs was evaluated using Bayesian and multivariate clustering methods. All analyses produced concordant results, identifying a major eastâwest split between two R. pipiens population clusters separated by the Missouri River. Substructuring within the two major identified population clusters was also found. Spatial principal component analysis (sPCA) and variance partitioning analysis identified distance, river basins, and the Missouri River as the most important landscape factors differentiating R. pipiens populations across the state. Bayesian reconstruction of coalescence times suggested the major eastâ west split occurred ~13â18 kya during a period of glacial retreat in the northern Great Plains and substructuring largely occurred ~5â11 kya during a period of extreme drought cycles. A rangeâwide species distribution model (SDM) for R. pipiens was developed and applied to prehistoric climate conditions during the Last Glacial Maximum (21 kya) and the midâHolocene (6 kya) from the CCSM4 climate model to identify potential refugia. The SDM indicated potential refugia existed in South Dakota or further south in Nebraska. The ancestral populations of R. pipiens in North Dakota may have inhabited these refugia, but more sampling outside the state is needed to reconstruct the route of colonization. Using microsatellite genotype data, this study determined that colonization from glacial refugia, drought dynamics in the northern Great Plains, and major rivers acting as barriers to gene flow were the defining forces shaping the regional population structure of R. pipiens in North Dakota
Get5 Carboxyl-terminal Domain Is a Novel Dimerization Motif That Tethers an Extended Get4/Get5 Complex
Tail-anchored trans-membrane proteins are targeted to membranes post-translationally. The proteins Get4 and Get5 form an obligate complex that catalyzes the transfer of tail-anchored proteins destined to the endoplasmic reticulum from Sgt2 to the cytosolic targeting factor Get3. Get5 forms a homodimer mediated by its carboxyl domain. We show here that a conserved motif exists within the carboxyl domain. A high resolution crystal structure and solution NMR structures of this motif reveal a novel and stable helical dimerization domain. We additionally determined a solution NMR structure of a divergent fungal homolog, and comparison of these structures allows annotation of specific stabilizing interactions. Using solution x-ray scattering and the structures of all folded domains, we present a model of the full-length Get4/Get5 complex
REENERGIZING THE U.S. AND PHILIPPINES RELATIONSHIP: THE âPHILIPPINES BELT AND ROADâ PROPOSAL
The purpose of this thesis is to examine why the United States should care about its future relationship with the Philippines through the overarching lens of Pankaj Ghemawatâs Cultural, Administrative, Geographic, and Economic (CAGE) Distance Framework. In addition, we will delve deeper to investigate a more direct approach using Michael E. Porterâs classic diamond model found in The Competitive Advantage of Nations. Using qualitative and exploratory research methods, we explore three questions. First, why should the United States care from a national security and alliance perspective about an economically stronger Philippines? Second, what does an economically stronger Philippines mean strategically for the United Statesâ influence in the Southeast Asian region? Finally, what can be done to strengthen the United States and the Philippines relationship? In conclusion, our recommendations provide tangible solutions to current gaps between the Philippines and the United States whether they be cultural, political, or military to facilitate a prosperous relationship while simultaneously thwarting the actions of the Chinese Communist Party (CCP) sweeping through Southeast Asia.Lieutenant Commander, United States NavyLieutenant Commander, United States NavyApproved for public release. Distribution is unlimited
Landscape genetics reveal broad and fineâscale population structure due to landscape features and climate history in the northern leopard frog (Rana pipiens) in North Dakota
Prehistoric climate and landscape features play large roles structuring wildlife populations. The amphibians of the northern Great Plains of North America present an opportunity to investigate how these factors affect colonization, migration, and current population genetic structure. This study used 11 microsatellite loci to genotype 1,230 northern leopard frogs (Rana pipiens) from 41 wetlands (30 samples/wetland) across North Dakota. Genetic structure of the sampled frogs was evaluated using Bayesian and multivariate clustering methods. All analyses produced concordant results, identifying a major eastâwest split between two R. pipiens population clusters separated by the Missouri River. Substructuring within the two major identified population clusters was also found. Spatial principal component analysis (sPCA) and variance partitioning analysis identified distance, river basins, and the Missouri River as the most important landscape factors differentiating R. pipiens populations across the state. Bayesian reconstruction of coalescence times suggested the major eastâ west split occurred ~13â18 kya during a period of glacial retreat in the northern Great Plains and substructuring largely occurred ~5â11 kya during a period of extreme drought cycles. A rangeâwide species distribution model (SDM) for R. pipiens was developed and applied to prehistoric climate conditions during the Last Glacial Maximum (21 kya) and the midâHolocene (6 kya) from the CCSM4 climate model to identify potential refugia. The SDM indicated potential refugia existed in South Dakota or further south in Nebraska. The ancestral populations of R. pipiens in North Dakota may have inhabited these refugia, but more sampling outside the state is needed to reconstruct the route of colonization. Using microsatellite genotype data, this study determined that colonization from glacial refugia, drought dynamics in the northern Great Plains, and major rivers acting as barriers to gene flow were the defining forces shaping the regional population structure of R. pipiens in North Dakota
Gauge symmetry and Slavnov-Taylor identities for randomly stirred fluids
The path integral for randomly forced incompressible fluids is shown to have
an underlying Becchi-Rouet-Stora (BRS) symmetry as a consequence of Galilean
invariance. This symmetry must be respected to have a consistent generating
functional, free from both an overall infinite factor and spurious relations
amongst correlation functions. We present a procedure for respecting this BRS
symmetry, akin to gauge fixing in quantum field theory. Relations are derived
between correlation functions of this gauge fixed, BRS symmetric theory,
analogous to the Slavnov-Taylor identities of quantum field theory.Comment: 5 pages, no figures, In Press Physical Review Letters, 200
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