Experiences and perspectives of farmers from Upstate New York farmers' markets     

Matthew R. Griffin  Edward A. Frongillo 《Agriculture and Human Values》2003,20(2):189-203

Despite the growing popularityof farmers' markets (FMs) across the UnitedStates, the experiences and perspectives offarmers who sell at markets have received verylittle research attention. This study describesthe views of 18 farmers from Upstate New Yorkon the importance of FMs as part of theirlifestyle and livelihood, the challenges theyface selling at markets, and their conceptionsof ideal FMs. Through in-depth, semi-structuredinterviews, farmers expressed economic andsocial motivations for selling at FMs; socialbenefits from interacting with customers; andthe challenges they faced as small-scalefarmers and sellers, including extra-marketcompetition, uncooperative and problematicmarket vendors, rising farm input costs, andchanging consumer trends. Farmers alsodiscussed personal values associated withselling at FMs, such as pride in raising andmarketing one's own products, working togetherwith other farmer-vendors, and providingcustomers with honest information. Visions ofideal FMs were varied among farmers, but therewas general agreement that FMs should provide adiversity of products to attract customers andeducational opportunities for the public tolearn more about FMs and local produce. Theinterdependence of FM farmers was a majoremergent theme across interviews. Findingssuggested that market experiences of FMfarmers, including economic success, are notonly contingent on personal effort, but canalso be affected by the work of fellow vendors.Future research may look to further explore howFM farmers and other vendors interact ascooperative and competitive social and economicunits. At the community level, FM leadershipshould continue to focus on the experiences andperspectives of farmers and other marketvendors, in addition to identifying ways forenhancing cooperative FM enterprises.  相似文献   

Traces of human migrations in Helicobacter pylori populations     

Falush D  Wirth T  Linz B  Pritchard JK  Stephens M  Kidd M  Blaser MJ  Graham DY  Vacher S  Perez-Perez GI  Yamaoka Y  Mégraud F  Otto K  Reichard U  Katzowitsch E  Wang X  Achtman M  Suerbaum S 《Science (New York, N.Y.)》2003,299(5612):1582-1585

Helicobacter pylori, a chronic gastric pathogen of human beings, can be divided into seven populations and subpopulations with distinct geographical distributions. These modern populations derive their gene pools from ancestral populations that arose in Africa, Central Asia, and East Asia. Subsequent spread can be attributed to human migratory fluxes such as the prehistoric colonization of Polynesia and the Americas, the neolithic introduction of farming to Europe, the Bantu expansion within Africa, and the slave trade.  相似文献   

Dentate gyrus NMDA receptors mediate rapid pattern separation in the hippocampal network     

McHugh TJ  Jones MW  Quinn JJ  Balthasar N  Coppari R  Elmquist JK  Lowell BB  Fanselow MS  Wilson MA  Tonegawa S 《Science (New York, N.Y.)》2007,317(5834):94-99

Forming distinct representations of multiple contexts, places, and episodes is a crucial function of the hippocampus. The dentate gyrus subregion has been suggested to fulfill this role. We have tested this hypothesis by generating and analyzing a mouse strain that lacks the gene encoding the essential subunit of the N-methyl-d-aspartate (NMDA) receptor NR1, specifically in dentate gyrus granule cells. The mutant mice performed normally in contextual fear conditioning, but were impaired in the ability to distinguish two similar contexts. A significant reduction in the context-specific modulation of firing rate was observed in the CA3 pyramidal cells when the mutant mice were transferred from one context to another. These results provide evidence that NMDA receptors in the granule cells of the dentate gyrus play a crucial role in the process of pattern separation.  相似文献   

Quantitative analysis of culture using millions of digitized books   总被引：1，自引：0，他引：1  

Michel JB  Shen YK  Aiden AP  Veres A  Gray MK;Google Books Team  Pickett JP  Hoiberg D  Clancy D  Norvig P  Orwant J  Pinker S  Nowak MA  Aiden EL 《Science (New York, N.Y.)》2011,331(6014):176-182

We constructed a corpus of digitized texts containing about 4% of all books ever printed. Analysis of this corpus enables us to investigate cultural trends quantitatively. We survey the vast terrain of 'culturomics,' focusing on linguistic and cultural phenomena that were reflected in the English language between 1800 and 2000. We show how this approach can provide insights about fields as diverse as lexicography, the evolution of grammar, collective memory, the adoption of technology, the pursuit of fame, censorship, and historical epidemiology. Culturomics extends the boundaries of rigorous quantitative inquiry to a wide array of new phenomena spanning the social sciences and the humanities.  相似文献   

RECENT PROGRESS IN PALEONTOLOGY     

Eastman CR  Gregory WK  Matthew WD 《Science (New York, N.Y.)》1917,45(1153):117-121

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THE ORIGIN OF PACIFIC ISLAND FAUNAS     

Matthew WD 《Science (New York, N.Y.)》1916,43(1115):686-687

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Adenovirus small e1a alters global patterns of histone modification     

Horwitz GA  Zhang K  McBrian MA  Grunstein M  Kurdistani SK  Berk AJ 《Science (New York, N.Y.)》2008,321(5892):1084-1085

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Does rejection hurt? An FMRI study of social exclusion   总被引：1，自引：0，他引：1  

Eisenberger NI  Lieberman MD  Williams KD 《Science (New York, N.Y.)》2003,302(5643):290-292

A neuroimaging study examined the neural correlates of social exclusion and tested the hypothesis that the brain bases of social pain are similar to those of physical pain. Participants were scanned while playing a virtual ball-tossing game in which they were ultimately excluded. Paralleling results from physical pain studies, the anterior cingulate cortex (ACC) was more active during exclusion than during inclusion and correlated positively with self-reported distress. Right ventral prefrontal cortex (RVPFC) was active during exclusion and correlated negatively with self-reported distress. ACC changes mediated the RVPFC-distress correlation, suggesting that RVPFC regulates the distress of social exclusion by disrupting ACC activity.  相似文献   

Deconfined quantum critical points     

Senthil T  Vishwanath A  Balents L  Sachdev S  Fisher MP 《Science (New York, N.Y.)》2004,303(5663):1490-1494

The theory of second-order phase transitions is one of the foundations of modern statistical mechanics and condensed-matter theory. A central concept is the observable order parameter, whose nonzero average value characterizes one or more phases. At large distances and long times, fluctuations of the order parameter(s) are described by a continuum field theory, and these dominate the physics near such phase transitions. We show that near second-order quantum phase transitions, subtle quantum interference effects can invalidate this paradigm, and we present a theory of quantum critical points in a variety of experimentally relevant two-dimensional antiferromagnets. The critical points separate phases characterized by conventional "confining" order parameters. Nevertheless, the critical theory contains an emergent gauge field and "deconfined" degrees of freedom associated with fractionalization of the order parameters. We propose that this paradigm for quantum criticality may be the key to resolving a number of experimental puzzles in correlated electron systems and offer a new perspective on the properties of complex materials.  相似文献   

Sequence variants in SLITRK1 are associated with Tourette's syndrome   总被引：1，自引：0，他引：1  

Abelson JF  Kwan KY  O'Roak BJ  Baek DY  Stillman AA  Morgan TM  Mathews CA  Pauls DL  Rasin MR  Gunel M  Davis NR  Ercan-Sencicek AG  Guez DH  Spertus JA  Leckman JF  Dure LS  Kurlan R  Singer HS  Gilbert DL  Farhi A  Louvi A  Lifton RP  Sestan N  State MW 《Science (New York, N.Y.)》2005,310(5746):317-320

Tourette's syndrome (TS) is a genetically influenced developmental neuropsychiatric disorder characterized by chronic vocal and motor tics. We studied Slit and Trk-like 1 (SLITRK1) as a candidate gene on chromosome 13q31.1 because of its proximity to a de novo chromosomal inversion in a child with TS. Among 174 unrelated probands, we identified a frameshift mutation and two independent occurrences of the identical variant in the binding site for microRNA hsa-miR-189. These variants were absent from 3600 control chromosomes. SLITRK1 mRNA and hsa-miR-189 showed an overlapping expression pattern in brain regions previously implicated in TS. Wild-type SLITRK1, but not the frameshift mutant, enhanced dendritic growth in primary neuronal cultures. Collectively, these findings support the association of rare SLITRK1 sequence variants with TS.  相似文献