406 research outputs found
Observations on Shorefast Ice Dynamics in Arctic Alaska and the Responses of the Iñupiat Hunting Community
Although shorefast sea ice forms a platform that facilitates travel, camping, and hunting by Iñupiat subsistence hunters and fishers in the western Arctic, the nearshore sea-ice zone remains an unforgiving and dynamic environment. Traditional hunters constantly hone site-specific experiences and skills with which to optimize the reward-to-risk ratio inherent in operating from this coastal ice. Nearshore ice conditions nevertheless can change suddenly, endangering even the most experienced subsistence hunters. This study examines two (of several) 20th-century events, 40 years apart, in which shorefast ice failed, threatening Iñupiat whale hunters with loss of confidence, livelihood, and life. These events differed in character. In one event, the shorefast ice was "crushed" by moving ice floes. In the other, the shorefast ice broke free of land. Our examination focuses on the relationship of subsistence hunters to the ice, the environmental causes of ice failures, the evolving technology for predicting ice behavior, and the longer-term implications of global change for this system. The complexity of geophysical processes underlying coastal ice behavior makes ice failures unpredictable. Thus, hunters must assume and manage risk. The variable and uncertain environment to which whale hunters are accustomed has produced an inherent flexibility that has helped them adapt to new conditions and will continue to do so in the future.Bien que la banquise côtière constitue une plate-forme qui permet aux Iñupiat de l'Arctique de l'Ouest de se déplacer et de camper lorsqu'ils pratiquent la chasse et la pêche de subsistance, la zone de banquise proche du littoral reste un milieu dynamique qui ne pardonne pas. Les chasseurs traditionnels améliorent constamment les habiletés et l'expérience reliées à des sites particuliers, qui leur permettent d'optimiser le rapport récompense-risque inhérent au fait de travailler depuis la glace côtière. Les conditions de cette dernière peuvent toutefois changer brusquement, mettant en danger même les chasseurs de subsistance les plus chevronnés. Cette étude se penche sur deux (parmi plusieurs) épisodes survenus au XXe siècle, à 40 ans d'écart, durant lesquels la banquise côtière s'est rompue, ébranlant la confiance des baleiniers Iñupiat et menaçant leur moyen de subsistance ainsi que leur vie. Ces événements étaient de nature différente. Dans l'un, la glace côtière avait été «écrasée» par des floes en dérive. Dans l'autre, la banquise côtière s'était détachée de la terre ferme. Notre étude se concentre sur le rapport entre les chasseurs de subsistance et la glace, les causes environnementales de la fragilisation de la glace, la technologie mise au point actuellement qui permettrait de prédire le comportement de la glace, et les implications à long terme du changement climatique pour ce système. La complexité des processus géophysiques sous-jacents au comportement de la banquise côtière fait que les ruptures de la banquise sont imprévisibles. Les chasseurs doivent donc assumer le risque et le gérer. L'environnement variable et incertain auquel sont accoutumés les chasseurs de baleine leur a donné une souplesse inhérente qui les a aidés à s'adapter à de nouvelles conditions et continuera de le faire dans l'avenir
Quantitative measurement of rainfall by radar
Reprint. Originally published: Journal American Water Works Association ; v. 46, no. 9 (September 1954).Cover title.Includes bibliographical references
Local BRST cohomology in the antifield formalism: II. Application to Yang-Mills theory
Yang-Mills models with compact gauge group coupled to matter fields are
considered. The general tools developed in a companion paper are applied to
compute the local cohomology of the BRST differential modulo the exterior
spacetime derivative for all values of the ghost number, in the space of
polynomials in the fields, the ghosts, the antifields (=sources for the BRST
variations) and their derivatives. New solutions to the consistency conditions
depending non trivially on the antifields are exhibited. For a
semi-simple gauge group, however, these new solutions arise only at ghost
number two or higher. Thus at ghost number zero or one, the inclusion of the
antifields does not bring in new solutions to the consistency condition
besides the already known ones. The analysis does not use power
counting and is purely cohomological. It can be easily extended to more general
actions containing higher derivatives of the curvature, or Chern-Simons terms.Comment: 30 pages Latex file, ULB-TH-94/07, NIKHEF-H 94-1
Cmr is a redox-responsive regulator of DosR that contributes to M. tuberculosis virulence.
Mycobacterium tuberculosis (MTb) is the causative agent of pulmonary tuberculosis (TB). MTb colonizes the human lung, often entering a non-replicating state before progressing to life-threatening active infections. Transcriptional reprogramming is essential for TB pathogenesis. In vitro, Cmr (a member of the CRP/FNR super-family of transcription regulators) bound at a single DNA site to act as a dual regulator of cmr transcription and an activator of the divergent rv1676 gene. Transcriptional profiling and DNA-binding assays suggested that Cmr directly represses dosR expression. The DosR regulon is thought to be involved in establishing latent tuberculosis infections in response to hypoxia and nitric oxide. Accordingly, DNA-binding by Cmr was severely impaired by nitrosation. A cmr mutant was better able to survive a nitrosative stress challenge but was attenuated in a mouse aerosol infection model. The complemented mutant exhibited a ∼2-fold increase in cmr expression, which led to increased sensitivity to nitrosative stress. This, and the inability to restore wild-type behaviour in the infection model, suggests that precise regulation of the cmr locus, which is associated with Region of Difference 150 in hypervirulent Beijing strains of Mtb, is important for TB pathogenesis
Analysis and Simulation of the Structure of Nanoparticles That Undergo a Surface-Driven Structural Transformation
This report addresses the analysis and simulation of the structure of nanoparticles that undergo a surface-driven structural transformation
Heirloom rice in Ifugao: an ‘anti-commodity’ in the process of commodification
We analyse the marketing of ‘heirloom rices’ produced in the Cordillera mountains of northern Luzon, the Philippines, as the commodification of a historical ‘anti-commodity’. We contend that, historically, rice was produced for social, cultural and spiritual purposes but not primarily for sale or trade. The Ifugaos were able to sustain terraced wet-rice cultivation within a system of ‘escape agriculture’ because they were protected from Spanish interference by the friction of terrain and distance. ‘Heirloom rice’ is a boundary concept that enables social entrepreneurs to commodify traditional landraces. We analyse the implications for local rice production and conservation efforts.Templeton Foundatio
Manipulating glucocorticoids in wild animals: Basic and applied perspectives
One of the most comprehensively studied responses to stressors in vertebrates is the endogenous production and regulation of glucocorticoids (GCs). Extensive laboratory research using experimental elevation of GCs in model species is instrumental in learning about stressor-induced physiological and behavioural mechanisms; however, such studies fail to inform our understanding of ecological and evolutionary processes in the wild. We reviewed emerging research that has used GC manipulations in wild vertebrates to assess GC-mediated effects on survival, physiology, behaviour, reproduction and offspring quality. Within and across taxa, exogenous manipulation of GCs increased, decreased or had no effect on traits examined in the reviewed studies. The notable diversity in r
Heavy Quarks and Heavy Quarkonia as Tests of Thermalization
We present here a brief summary of new results on heavy quarks and heavy
quarkonia from the PHENIX experiment as presented at the "Quark Gluon Plasma
Thermalization" Workshop in Vienna, Austria in August 2005, directly following
the International Quark Matter Conference in Hungary.Comment: 8 pages, 5 figures, Quark Gluon Plasma Thermalization Workshop
(Vienna August 2005) Proceeding
Proximity effect at superconducting Sn-Bi2Se3 interface
We have investigated the conductance spectra of Sn-Bi2Se3 interface junctions
down to 250 mK and in different magnetic fields. A number of conductance
anomalies were observed below the superconducting transition temperature of Sn,
including a small gap different from that of Sn, and a zero-bias conductance
peak growing up at lower temperatures. We discussed the possible origins of the
smaller gap and the zero-bias conductance peak. These phenomena support that a
proximity-effect-induced chiral superconducting phase is formed at the
interface between the superconducting Sn and the strong spin-orbit coupling
material Bi2Se3.Comment: 7 pages, 8 figure
Centrality Dependence of the High p_T Charged Hadron Suppression in Au+Au collisions at sqrt(s_NN) = 130 GeV
PHENIX has measured the centrality dependence of charged hadron p_T spectra
from central Au+Au collisions at sqrt(s_NN)=130 GeV. The truncated mean p_T
decreases with centrality for p_T > 2 GeV/c, indicating an apparent reduction
of the contribution from hard scattering to high p_T hadron production. For
central collisions the yield at high p_T is shown to be suppressed compared to
binary nucleon-nucleon collision scaling of p+p data. This suppression is
monotonically increasing with centrality, but most of the change occurs below
30% centrality, i.e. for collisions with less than about 140 participating
nucleons. The observed p_T and centrality dependence is consistent with the
particle production predicted by models including hard scattering and
subsequent energy loss of the scattered partons in the dense matter created in
the collisions.Comment: 7 pages text, LaTeX, 6 figures, 2 tables, 307 authors, resubmitted to
Phys. Lett. B. Revised to address referee concerns. Plain text data tables
for the points plotted in figures for this and previous PHENIX publications
are publicly available at
http://www.phenix.bnl.gov/phenix/WWW/run/phenix/papers.htm
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