140 research outputs found
Rural People, Rural Places: The Hidden Costs of Hurricane Katrina
This brief shows how the characteristics of rural Gulf Coast families place them at higher risks during natural disasters and make them far less able to recover from such calamities. Although few realize it, nonmetro residents represented the majority (55%) of the population affected by Hurricane Katrina in Mississippi. They also constituted 17% of the people living in Alabama's disaster-stricken area, and about 12% of the affected population in Louisiana. These are not inconsequential numbers; they represent thousands of inhabitants living in small communities dotting the tri-state region. This Rural Realities brief draws much needed attention to nonmetro areas affected by Hurricane Katrina and outlines the key features of the rural people and places that have been impacted by this major disaster. Most important, it offers a series of policy recommendations that can assist in rebuilding the region's nonmetro counties and parishes. The hope is that these policy ideas can offer a meaningful set of strategies for lessening the future vulnerability of rural areas within and outside this region of the country. This brief is from Rural Realities; Volume 1, Issue 2. Rural Realities is published by the Rural Sociological Society. It is a peer-reviewed, web-based series that is published four times a year. Each issue is devoted to a single topic
Unveiling Dust-enshrouded Star Formation in the Early Universe: a Sub-mm Survey of the Hubble Deep Field
The advent of sensitive sub-mm array cameras now allows a proper census of
dust-enshrouded massive star-formation in very distant galaxies, previously
hidden activity to which even the faintest optical images are insensitive. We
present the deepest sub-mm survey of the sky to date, taken with the SCUBA
camera on the James Clerk Maxwell Telescope and centred on the Hubble Deep
Field. The high source density found in this image implies that the survey is
confusion-limited below a flux density of 2 mJy. However, within the central 80
arcsec radius independent analyses yield 5 reproducible sources with S(850um) >
2 mJy which simulations indicate can be ascribed to individual galaxies. We
give positions and flux densities for these, and furthermore show using
multi-frequency photometric data that the brightest sources in our map lie at
redshifts z~3. These results lead to integral source counts which are
completely inconsistent with a no-evolution model, and imply that massive
star-formation activity continues at redshifts > 2. The combined brightness of
the 5 most secure sources in our map is sufficient to account for 30 - 50% of
the previously unresolved sub-mm background, and we estimate statistically that
the entire background is resolved at about the 0.3 mJy level. Finally we
discuss possible optical identifications and redshift estimates for the
brightest sources. One source appears to be associated with an extreme
starburst galaxy at z~1, whilst the remaining four appear to lie in the
redshift range 2 < z < 4. This implies a star-formation density over this
redshift range that is at least five times higher than that inferred from the
ultraviolet output of HDF galaxies.Comment: 19 pages, 6 figures (to appear as a Nature Article
A Submillimetre Survey of the Hubble Deep Field: Unveiling Dust-Enshrouded Star Formation in the Early Universe
The advent of sensitive sub-mm array cameras now allows a proper census of
dust-enshrouded massive star-formation in very distant galaxies, previously
hidden activity to which even the deepest optical images are insensitive. We
present the deepest sub-mm survey, taken with the SCUBA camera on the James
Clerk Maxwell Telescope (JCMT) and centred on the Hubble Deep Field (HDF). The
high source density on this image implies that the survey is confusion-limited
below a flux density of 2 mJy. However within the central 80 arcsec radius
independent analyses yield 5 reproducible sources with S(850um) > 2 mJy which
simulations indicate can be ascribed to individual galaxies. These data lead to
integral source counts which are completely inconsistent with a no evolution
model, whilst the combined brightness of the 5 most secure sources in our map
is sufficient to account for 30-50% of the previously unresolved sub-mm
background, and statistically the entire background is resolved at about the
0.3 mJy level. Four of the five brightest sources appear to be associated with
galaxies which lie in the redshift range 2 < z < 4. With the caveat that this
is a small sample of sources detected in a small survey area, these submm data
imply a star-formation density over this redshift range that is at least five
times higher than that inferred from the rest-frame ultraviolet output of HDF
galaxies.Comment: to appear in the proceedings of `The Birth of Galaxies', Xth
Rencontres de Blois, 4 pages, 1 postscript figure, uses blois.sty (included
Strong interface-induced spin-orbit coupling in graphene on WS2
Interfacial interactions allow the electronic properties of graphene to be
modified, as recently demonstrated by the appearance of satellite Dirac cones
in the band structure of graphene on hexagonal boron nitride (hBN) substrates.
Ongoing research strives to explore interfacial interactions in a broader class
of materials in order to engineer targeted electronic properties. Here we show
that at an interface with a tungsten disulfide (WS2) substrate, the strength of
the spin-orbit interaction (SOI) in graphene is very strongly enhanced. The
induced SOI leads to a pronounced low-temperature weak anti-localization (WAL)
effect, from which we determine the spin-relaxation time. We find that
spin-relaxation time in graphene is two-to-three orders of magnitude smaller on
WS2 than on SiO2 or hBN, and that it is comparable to the intervalley
scattering time. To interpret our findings we have performed first-principle
electronic structure calculations, which both confirm that carriers in
graphene-on-WS2 experience a strong SOI and allow us to extract a
spin-dependent low-energy effective Hamiltonian. Our analysis further shows
that the use of WS2 substrates opens a possible new route to access topological
states of matter in graphene-based systems.Comment: Originally submitted version in compliance with editorial guidelines.
Final version with expanded discussion of the relation between theory and
experiments to be published in Nature Communication
The impact of preâoperative intravenous iron on quality of life after colorectal cancer surgery: outcomes from the intravenous iron in colorectal cancerâassociated anaemia (IVICA) trial
Anaemia is associated with a reduction in quality of life, and is common in patients with colorectal cancer . Werecently reported thefindings of the intravenous iron in colorectal cancer-associated anaemia (IVICA) trialcomparing haemoglobin levels and transfusion requirements following intravenous or oral iron replacement inanaemic colorectal cancer patients undergoing elective surgery. In this follow-up study, we compared theefficacy of intravenous and oral iron at improving quality of life in this patient group. We conducted amulticentre, open-label randomised controlled trial. Anaemic colorectal cancer patients were randomlyallocated at least two weeks pre-operatively, to receive either oral (ferrous sulphate) or intravenous (ferriccarboxymaltose) iron. We assessed haemoglobin and quality of life scores at recruitment, immediately beforesurgery and at outpatient review approximately three months postoperatively, using the Short Form 36,EuroQoL 5-dimension 5-level and Functional Assessment of Cancer TherapyâAnaemia questionnaires. Werecruited 116 anaemic patients across seven UK centres (oral iron n=61 (53%), and intravenous iron n=55(47%)). Eleven quality of life components increased by a clinically significant margin in the intravenous irongroup between recruitment and surgery compared with one component for oral iron. Median (IQR [range])visual analogue scores were significantly higher with intravenous iron at a three month outpatient review (oraliron 70, (60â85 [20â95]); intravenous iron 90 (80â90 [50â100]), p=0.001). The Functional Assessment ofCancer TherapyâAnaemia score comprises of subscales related to cancer, fatigue and non-fatigue itemsrelevant to anaemia. Median outpatient scores were higher, and hence favourable, for intravenous iron on theFunctional Assessment of Cancer TherapyâAnaemia subscale (oral iron 66 (55â72 [23â80]); intravenous iron 71(66â77 [46â80]); p=0.002), Functional Assessment of Cancer TherapyâAnaemia trial outcome index (oral iron108 (90â123 [35â135]); intravenous iron 121 (113â124 [81â135]); p=0.003) and Functional Assessment ofCancer TherapyâAnaemia total score (oral iron 151 (132â170 [69â183]); intravenous iron 168 (160â174 [125â186]); p=0.005). Thesefindings indicate that intravenous iron is more efficacious at improving quality of lifescores than oral iron in anaemic colorectal cancer patients
Accuracy of advanced versus strictly conventional 12-lead ECG for detection and screening of coronary artery disease, left ventricular hypertrophy and left ventricular systolic dysfunction
<p>Abstract</p> <p>Background</p> <p>Resting conventional 12-lead ECG has low sensitivity for detection of coronary artery disease (CAD) and left ventricular hypertrophy (LVH) and low positive predictive value (PPV) for prediction of left ventricular systolic dysfunction (LVSD). We hypothesized that a ~5-min resting 12-lead <it>advanced </it>ECG test ("A-ECG") that combined results from both the advanced and conventional ECG could more accurately screen for these conditions than strictly conventional ECG.</p> <p>Methods</p> <p>Results from nearly every conventional and advanced resting ECG parameter known from the literature to have diagnostic or predictive value were first retrospectively evaluated in 418 healthy controls and 290 patients with imaging-proven CAD, LVH and/or LVSD. Each ECG parameter was examined for potential inclusion within multi-parameter A-ECG scores derived from multivariate regression models that were designed to optimally screen for disease in general or LVSD in particular. The performance of the best retrospectively-validated A-ECG scores was then compared against that of optimized pooled criteria from the strictly conventional ECG in a test set of 315 additional individuals.</p> <p>Results</p> <p>Compared to optimized pooled criteria from the strictly conventional ECG, a 7-parameter A-ECG score validated in the training set increased the sensitivity of resting ECG for identifying disease in the test set from 78% (72-84%) to 92% (88-96%) (P < 0.0001) while also increasing specificity from 85% (77-91%) to 94% (88-98%) (P < 0.05). In diseased patients, another 5-parameter A-ECG score increased the PPV of ECG for LVSD from 53% (41-65%) to 92% (78-98%) (P < 0.0001) without compromising related negative predictive value.</p> <p>Conclusion</p> <p>Resting 12-lead A-ECG scoring is more accurate than strictly conventional ECG in screening for CAD, LVH and LVSD.</p
Seasonal drought limits tree species across the Neotropics
Within the tropics, the species richness of tree communities is strongly and positively associated with precipitation. Previous research has suggested that this macroecological pattern is driven by the negative effect of water-stress on the physiological processes of most tree species. This process implies that the range limits of taxa are defined by their ability to occur under dry conditions, and thus in terms of species distributions it predicts a nested pattern of taxa distribution from wet to dry areas. However, this âdry-toleranceâ hypothesis has yet to be adequately tested at large spatial and taxonomic scales. Here, using a dataset of 531 inventory plots of closed canopy forest distributed across the Western Neotropics we investigated how precipitation, evaluated both as mean annual precipitation and as the maximum climatological water deficit, influences the distribution of tropical tree species, genera and families. We find that the distributions of tree taxa are indeed nested along precipitation gradients in the western Neotropics. Taxa tolerant to seasonal drought are disproportionally widespread across the precipitation gradient, with most reaching even the wettest climates sampled; however, most taxa analysed are restricted to wet areas. Our results suggest that the âdry toleranceâ hypothesis has broad applicability in the world's most species-rich forests. In addition, the large number of species restricted to wetter conditions strongly indicates that an increased frequency of drought could severely threaten biodiversity in this region. Overall, this study establishes a baseline for exploring how tropical forest tree composition may change in response to current and future environmental changes in this region
Review of Particle Physics (2010)
A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: pdg.lbl.gov.This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2158 new measurements from 551 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. Among the 108 reviews are many that are new or heavily revised including those on neutrino mass, mixing, and oscillations, QCD, top quark, CKM quark-mixing matrix, Vud & Vus, Vcb & Vub, fragmentation functions, particle detectors for accelerator and non-accelerator physics, magnetic monopoles, cosmological parameters, and big bang cosmology.MICINN, Spain (FPA2009-07264-E). The publication of the Review of Particle Physics is supported by the Director, Office of Science, Office of High Energy and Nuclear Physics, the Division of High Energy Physics of the U.S. Department of Energy under Contract No. DEâAC02â05CH11231; by the U.S. National Science Foundation under Agreement No. PHY-0652989; by the European Laboratory for Particle Physics (CERN); by an implementing arrangement between the governments of Japan (MEXT: Ministry of Education, Culture, Sports, Science and Technology) and the United States (DOE) on cooperative research and development; and by the Italian National Institute of Nuclear Physics (INFN)
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