GSTDTAP

浏览/检索结果: 共234条,第1-10条 帮助

限定条件                    
已选(0)清除 条数/页:   排序方式:
Earth and field observations underpin metapopulation dynamics in complex landscapes: Near-term study on carabids 期刊论文
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2020, 117 (23) : 12877-12884
作者:  Giezendanner, Jonathan;  Pasetto, Damiano;  Perez-Saez, Javier;  Cerrato, Cristiana;  Viterbi, Ramona;  Terzago, Silvia;  Palazzi, Elisa;  Rinaldo, Andrea
收藏  |  浏览/下载:6/0  |  提交时间:2020/06/01
species distribution models  metapopulation ecology  landscape matrix  Earth observation  carabids  
An Alternative BEM for Simulating the Flow Behavior of a Leaky Confined Fractured Aquifer With the Use of the Semianalytical Approach 期刊论文
WATER RESOURCES RESEARCH, 2020, 56 (5)
作者:  Luo, Wanjing;  Wang, Junlei;  Wang, Lei;  Zhou, Y.
收藏  |  浏览/下载:7/0  |  提交时间:2020/07/02
boundary element method  continuously confined fractured aquifer  discretely confined fractured aquifer  Green'  s function  transient flow behavior  
An acute immune response underlies the benefit of cardiac stem cell therapy 期刊论文
NATURE, 2020, 577 (7790) : 405-+
作者:  Schmacke, Niklas A.;  Hornung, Veit
收藏  |  浏览/下载:20/0  |  提交时间:2020/07/03

Clinical trials using adult stem cells to regenerate damaged heart tissue continue to this day(1,2), despite ongoing questions of efficacy and a lack of mechanistic understanding of the underlying biological effect(3). The rationale for these cell therapy trials is derived from animal studies that show a modest but reproducible improvement in cardiac function in models of cardiac ischaemic injury(4,5). Here we examine the mechanistic basis for cell therapy in mice after ischaemia-reperfusion injury, and find that-although heart function is enhanced-it is not associated with the production of new cardiomyocytes. Cell therapy improved heart function through an acute sterile immune response characterized by the temporal and regional induction of CCR2(+) and CX3CR1(+) macrophages. Intracardiac injection of two distinct types of adult stem cells, cells killed by freezing and thawing or a chemical inducer of the innate immune response all induced a similar regional accumulation of CCR2(+) and CX3CR1(+) macrophages, and provided functional rejuvenation to the heart after ischaemia-reperfusion injury. This selective macrophage response altered the activity of cardiac fibroblasts, reduced the extracellular matrix content in the border zone and enhanced the mechanical properties of the injured area. The functional benefit of cardiac cell therapy is thus due to an acute inflammatory-based wound-healing response that rejuvenates the infarcted area of the heart.


  
The first dinosaur egg was soft 期刊论文
NATURE, 2020
作者:  Rodstrom, Karin E. J.;  Kiper, Aytug K.;  Zhang, Wei;  Rinne, Susanne;  Pike, Ashley C. W.;  Goldstein, Matthias;  Conrad, Linus J.;  Delbeck, Martina;  Hahn, Michael G.;  Meier, Heinrich;  Platzk, Magdalena;  Quigley, Andrew;  Speedman, David;  Shrestha, Leela;  Mukhopadhyay, Shubhashish M. M.
收藏  |  浏览/下载:47/0  |  提交时间:2020/07/03

Molecular analyses of newly discovered, embryo-bearing ornithischian and sauropod dinosaur eggs suggest that the ancestral dinosaur egg was soft-shelled, and that hard-shelled eggs evolved independently at least three times in the major dinosaur lineages.


Calcified eggshells protect developing embryos against environmental stress and contribute to reproductive success(1). As modern crocodilians and birds lay hard-shelled eggs, this eggshell type has been inferred for non-avian dinosaurs. Known dinosaur eggshells are characterized by an innermost membrane, an overlying protein matrix containing calcite, and an outermost waxy cuticle(2-7). The calcitic eggshell consists of one or more ultrastructural layers that differ markedly among the three major dinosaur clades, as do the configurations of respiratory pores. So far, only hadrosaurid, a few sauropodomorph and tetanuran eggshells have been discovered  the paucity of the fossil record and the lack of intermediate eggshell types challenge efforts to homologize eggshell structures across all dinosaurs(8-18). Here we present mineralogical, organochemical and ultrastructural evidence for an originally non-biomineralized, soft-shelled nature of exceptionally preserved ornithischianProtoceratopsand basal sauropodomorphMussauruseggs. Statistical evaluation of in situ Raman spectra obtained for a representative set of hard- and soft-shelled, fossil and extant diapsid eggshells clusters the originally organic but secondarily phosphatizedProtoceratopsand the organicMussauruseggshells with soft, non-biomineralized eggshells. Histology corroborates the organic composition of these soft-shelled dinosaur eggs, revealing a stratified arrangement resembling turtle soft eggshell. Through an ancestral-state reconstruction of composition and ultrastructure, we compare eggshells fromProtoceratopsandMussauruswith those from other diapsids, revealing that the first dinosaur egg was soft-shelled. The calcified, hard-shelled dinosaur egg evolved independently at least three times throughout the Mesozoic era, explaining the bias towards eggshells of derived dinosaurs in the fossil record.


  
APOE4 leads to blood-brain barrier dysfunction predicting cognitive decline 期刊论文
NATURE, 2020, 581 (7806) : 70-+
作者:  Doherty, Tiarnan A. S.;  Winchester, Andrew J.;  Macpherson, Stuart;  Johnstone, Duncan N.;  Pareek, Vivek;  Tennyson, Elizabeth M.;  Kosar, Sofiia;  Kosasih, Felix U.;  Anaya, Miguel;  Abdi-Jalebi, Mojtaba;  Andaji-Garmaroudi, Zahra;  Wong, E. Laine;  Madeo, Julien;  Chiang, Yu-Hsien;  Park, Ji-Sang;  Jung, Young-Kwang;  Petoukhoff, Christopher E.;  Divitini, Giorgio;  Man, Michael K. L.;  Ducati, Caterina;  Walsh, Aron;  Midgley, Paul A.;  Dani, Keshav M.;  Stranks, Samuel D.
收藏  |  浏览/下载:25/0  |  提交时间:2020/07/03

Breakdown of the blood-brain barrier in individuals carrying the epsilon 4 allele of the APOE gene, but not the epsilon 3 allele, increases with and predicts cognitive impairment and is independent of amyloid beta or tau pathology.


Vascular contributions to dementia and Alzheimer'  s disease are increasingly recognized(1-6). Recent studies have suggested that breakdown of the blood-brain barrier (BBB) is an early biomarker of human cognitive dysfunction(7), including the early clinical stages of Alzheimer'  s disease(5,8-10). The E4 variant of apolipoprotein E (APOE4), the main susceptibility gene for Alzheimer'  s disease(11-14), leads to accelerated breakdown of the BBB and degeneration of brain capillary pericytes(15-19), which maintain BBB integrity(20-22). It is unclear, however, whether the cerebrovascular effects of APOE4 contribute to cognitive impairment. Here we show that individuals bearing APOE4 (with the epsilon 3/epsilon 4 or epsilon 4/epsilon 4 alleles) are distinguished from those without APOE4 (epsilon 3/epsilon 3) by breakdown of the BBB in the hippocampus and medial temporal lobe. This finding is apparent in cognitively unimpaired APOE4 carriers and more severe in those with cognitive impairment, but is not related to amyloid-beta or tau pathology measured in cerebrospinal fluid or by positron emission tomography(23). High baseline levels of the BBB pericyte injury biomarker soluble PDGFR beta(7,8) in the cerebrospinal fluid predicted future cognitive decline in APOE4 carriers but not in non-carriers, even after controlling for amyloid-beta and tau status, and were correlated with increased activity of the BBB-degrading cyclophilin A-matrix metalloproteinase-9 pathway(19) in cerebrospinal fluid. Our findings suggest that breakdown of the BBB contributes to APOE4-associated cognitive decline independently of Alzheimer'  s disease pathology, and might be a therapeutic target in APOE4 carriers.


  
Water Resources as Determinants for Foreign Direct Investments in Land - A Gravity Analysis of Foreign Land Acquisitions 期刊论文
ECOLOGICAL ECONOMICS, 2020, 170
作者:  Hirsch, Cornelius;  Krisztin, Tamas;  See, Linda
收藏  |  浏览/下载:12/0  |  提交时间:2020/07/02
FDI  Foreign Land Acquisition  Bilateral Trade Agreements  Water Resources  Precipitation  Yield Gap  Gravity model  PPML  ZIP  
Upscaling Water Flow in Composite Nanoporous Shale Matrix Using Lattice Boltzmann Method 期刊论文
WATER RESOURCES RESEARCH, 2020, 56 (4)
作者:  Zhang, Tao;  Javadpour, Farzam;  Yin, Ying;  Li, Xiangfang
收藏  |  浏览/下载:6/0  |  提交时间:2020/07/02
shale  flow  nanopores  liquid slip  digital rocks  lattice Boltzmann method  
A positively selected FBN1 missense variant reduces height in Peruvian individuals 期刊论文
NATURE, 2020, 582 (7811) : 234-+
作者:  Bedford, Jonathan R.;  Moreno, Marcos;  Deng, Zhiguo;  Oncken, Onno;  Schurr, Bernd;  John, Timm;  Baez, Juan Carlos;  Bevis, Michael
收藏  |  浏览/下载:14/0  |  提交时间:2020/07/03

On average, Peruvian individuals are among the shortest in the world(1). Here we show that Native American ancestry is associated with reduced height in an ethnically diverse group of Peruvian individuals, and identify a population-specific, missense variant in the FBN1 gene (E1297G) that is significantly associated with lower height. Each copy of the minor allele (frequency of 4.7%) reduces height by 2.2 cm (4.4 cm in homozygous individuals). To our knowledge, this is the largest effect size known for a common height-associated variant. FBN1 encodes the extracellular matrix protein fibrillin 1, which is a major structural component of microfibrils. We observed less densely packed fibrillin-1-rich microfibrils with irregular edges in the skin of individuals who were homozygous for G1297 compared with individuals who were homozygous for E1297. Moreover, we show that the E1297G locus is under positive selection in non-African populations, and that the E1297 variant shows subtle evidence of positive selection specifically within the Peruvian population. This variant is also significantly more frequent in coastal Peruvian populations than in populations from the Andes or the Amazon, which suggests that short stature might be the result of adaptation to factors that are associated with the coastal environment in Peru.


In an ethnically diverse group of Peruvian individuals, the population-specific, missense variant in FBN1 (E1297G) is associated with lower height and shows evidence of positive selection within the Peruvian population.


  
Temperate rainforests near the South Pole during peak Cretaceous warmth 期刊论文
NATURE, 2020, 580 (7801) : 81-+
作者:  Johann P. Klages;  Ulrich Salzmann;  Torsten Bickert;  Claus-Dieter Hillenbrand;  Karsten Gohl;  Gerhard Kuhn;  Steven M. Bohaty;  ;  rgen Titschack;  Juliane Mü;  ller;  Thomas Frederichs;  Thorsten Bauersachs;  Werner Ehrmann;  Tina van de Flierdt;  Patric Simõ;  es Pereira;  Robert D. Larter;  Gerrit Lohmann;  Igor Niezgodzki;  Gabriele Uenzelmann-Neben;  Maximilian Zundel;  Cornelia Spiegel;  Chris Mark;  David Chew;  Jane E. Francis;  Gernot Nehrke;  Florian Schwarz;  James A. Smith;  Tim Freudenthal;  Oliver Esper;  Heiko Pä;  like;  Thomas A. Ronge;  Ricarda Dziadek
收藏  |  浏览/下载:12/0  |  提交时间:2020/05/13

The mid-Cretaceous period was one of the warmest intervals of the past 140 million years(1-5), driven by atmospheric carbon dioxide levels of around 1,000 parts per million by volume(6). In the near absence of proximal geological records from south of the Antarctic Circle, it is disputed whether polar ice could exist under such environmental conditions. Here we use a sedimentary sequence recovered from the West Antarctic shelf-the southernmost Cretaceous record reported so far-and show that a temperate lowland rainforest environment existed at a palaeolatitude of about 82 degrees S during the Turonian-Santonian age (92 to 83 million years ago). This record contains an intact 3-metre-long network of in situ fossil roots embedded in a mudstone matrix containing diverse pollen and spores. A climate model simulation shows that the reconstructed temperate climate at this high latitude requires a combination of both atmospheric carbon dioxide concentrations of 1,120-1,680 parts per million by volume and a vegetated land surface without major Antarctic glaciation, highlighting the important cooling effect exerted by ice albedo under high levels of atmospheric carbon dioxide.


  
A Particle-Based Conditional Sampling Scheme for the Simulation of Transport in Fractured Rock With Diffusion Into Stagnant Water and Rock Matrix 期刊论文
WATER RESOURCES RESEARCH, 2020, 56 (4)
作者:  Trinchero, Paolo;  Painter, Scott L.;  Poteri, Antti;  Sanglas, Jordi;  Cvetkovic, Vladimir;  Selroos, Jan-Olof
收藏  |  浏览/下载:6/0  |  提交时间:2020/07/02
fractured media  diffusion into stagnant water  time domain particle tracking  retention time distribution