511 research outputs found
Reducing the burden of injury: An intersectoral preventive approach is needed
Injuries constitute the second largest contributor to the Western Cape burden of disease (BoD), after major infectious diseases caused by HIV/AIDS and tuberculosis and ahead of mental health disorders and cardiovascular and childhood diseases. The Provincial Health Department instituted the BoD Reduction Project to improve health surveillance for planning and resource allocation, review risk factors, and prioritise interventions to reduce the overall BoD
Employment mobility in high-technology agglomerations: the cases of Oxfordshire and Cambridgeshire
This paper examines labour market behaviour of the highly skilled in high-tech local economies, taking the UK examples of Oxfordshire and Cambridgeshire as case studies. It reports on data from a survey of members of three scientific institutes to compare rates of employee mobility in the two locations and considers the likely explanations and implications of those patterns
Persistent Disparities between Recent Rates of Habitat Conversion and Protection and Implications for Future Global Conservation Targets
Anthropogenic conversion of natural habitats is the greatest threat to biodiversity and one of the primary reasons for establishing protected areas (PAs). Here, we show that PA establishment outpaced habitat conversion between 1993 and 2009 across all biomes and the majority (n = 567, 71.4%) of ecoregions globally. However, high historic rates of conversion meant that 447 (56.2%) ecoregions still exhibit a high ratio of conversion to protection, and of these, 127 (15.9%) experienced further increases in this ratio between 1993 and 2009. We identify 41 âcrisis ecoregionsâ in 45 countries where recent habitat conversion is severe and PA coverage remains extremely low. While the recent growth in PAs is a notable conservation achievement, international conventions and associated finance mechanisms should prioritize areas where habitat is being lost rapidly relative to protection, such as the crisis ecoregions identified here
Identifying global centers of unsustainable commercial harvesting of species
Overexploitation is one of the main threats to biodiversity, but the intensity of this threat varies geographically. We identified global concentrations, on land and at sea, of 4543 species threatened by unsustainable commercial harvesting. Regions under high-intensity threat (based on accessibility on land and on fishing catch at sea) cover 4.3% of the land and 6.1% of the seas and contain 82% of all species threatened by unsustainable harvesting and > 80% of the ranges of Critically Endangered species threatened by unsustainable harvesting. Currently, only 16% of these regions are covered by protected areas on land and just 6% at sea. Urgent actions are needed in these centers of unsustainable harvesting to ensure that use of species is sustainable and to prevent further species' extinctions.Peer reviewe
Hydrocarbon Dust Absorption in Seyfert Galaxies and ULIRGs
We present new spectroscopic observations of the 3.4 micron absorption
feature in the Seyfert galaxies, NGC1068 and NGC7674, and the ultraluminous
infrared galaxy, IRAS08572+3915. A signature of C-H bonds in aliphatic
hydrocarbons, the 3.4 micron feature indicates the presence of organic material
in Galactic and extragalactic dust. Here we compare the 3.4 micron feature in
all the galaxies in which it has been detected. In several cases, the
signal-to-noise ratio and spectral resolution permit a detailed examination of
the feature profile, something which has rarely been attempted in extragalactic
lines of sight. The 3.4 micron band in these galaxies closely resembles that
seen in the Galactic diffuse ISM and in newly-formed dust in a protoplanetary
nebula. The similarity implies a common carrier for the carbonaceous component
of dust, and one which is resistant to processing in the interstellar and/or
circumnuclear medium. We also examine the mid-IR spectrum of NGC1068, because
absorption bands in the 5-8 micron region further constrain the chemistry of
the 3.4 micron band carrier. While weak features like those present in the
mid-IR spectrum of diffuse dust towards the Galactic center would be
undetectable in NGC1068, the strong bands found in the spectra of many proposed
dust analog materials are clearly absent, eliminating certain candidates and
production mechanisms for the carrier. The absence of strong absorption
features at 5-8 microns is also consistent with the interpretation that the
similarity in the 3.4 micron feature in NGC1068 to that in Galactic lines of
sight reflects real chemical similarity in the carbonaceous dust.Comment: 30 pages, 8 figures (preprint style), ApJ accepte
Multimodel climate and variability of the stratosphere
The stratospheric climate and variability from simulations of sixteen chemistryâclimate models is evaluated. On average the polar night jet is well reproduced though its variability is less well reproduced with a large spread between models. Polar temperature biases are less than 5 K except in the Southern Hemisphere (SH) lower stratosphere in spring. The accumulated area of low temperatures responsible for polar stratospheric cloud formation is accurately reproduced for the Antarctic but underestimated for the Arctic. The shape and position of the polar vortex is well simulated, as is the tropical upwelling in the lower stratosphere. There is a wide model spread in the frequency of major sudden stratospheric warnings (SSWs), late biases in the breakup of the SH vortex, and a weak annual cycle in the zonal wind in the tropical upper stratosphere. Quantitatively, âmetricsâ indicate a wide spread in model performance for most diagnostics with systematic biases in many, and poorer performance in the SH than in the Northern Hemisphere (NH). Correlations were found in the SH between errors in the final warming, polar temperatures, the leading mode of variability, and jet strength, and in the NH between errors in polar temperatures, frequency of major SSWs, and jet strength. Models with a stronger QBO have stronger tropical upwelling and a colder NH vortex. Both the qualitative and quantitative analysis indicate a number of common and longâstanding model problems, particularly related to the simulation of the SH and stratospheric variability
Chemistryâclimate model simulations of twenty-first century stratospheric climate and circulation changes
The response of stratospheric climate and circulation to increasing amounts of greenhouse gases (GHGs) and ozone recovery in the twenty-first century is analyzed in simulations of 11 chemistryâclimate models using near-identical forcings and experimental setup. In addition to an overall global cooling of the stratosphere in the simulations (0.59 6 0.07 K decade21 at 10 hPa), ozone recovery causes a warming of the Southern Hemisphere polar lower stratosphere in summer with enhanced cooling above. The rate of warming correlates with the rate of ozone recovery projected by the models and, on average, changes from 0.8 to 0.48 Kdecade21 at 100 hPa as the rate of recovery declines from the first to the second half of the century. In the winter northern polar lower stratosphere the increased radiative cooling from the growing abundance of GHGs is, in most models, balanced by adiabatic warming from stronger polar downwelling. In the Antarctic lower stratosphere the models simulate an increase in low temperature extremes required for polar stratospheric cloud (PSC) formation, but the positive trend is decreasing over the twenty-first century in all models. In the Arctic, none of the models simulates a statistically significant increase in Arctic PSCs throughout the twenty-first century. The subtropical jets accelerate in response to climate change and the ozone recovery produces awestward acceleration of the lower-stratosphericwind over theAntarctic during summer, though this response is sensitive to the rate of recovery projected by the models. There is a strengthening of the BrewerâDobson circulation throughout the depth of the stratosphere, which reduces the mean age of air nearly everywhere at a rate of about 0.05 yr decade21 in those models with this diagnostic. On average, the annual mean tropical upwelling in the lower stratosphere (;70 hPa) increases by almost 2% decade21, with 59% of this trend forced by the parameterized orographic gravity wave drag in the models. This is a consequence of the eastward acceleration of the subtropical jets, which increases the upward flux of (parameterized) momentum reaching the lower stratosphere in these latitudes
Multimodel assessment of the factors driving stratospheric ozone evolution over the 21st century
The evolution of stratospheric ozone from 1960 to 2100 is examined in simulations from 14 chemistryâclimate models, driven by prescribed levels of halogens and greenhouse gases. There is general agreement among the models that total column ozone reached a minimum around year 2000 at all latitudes, projected to be followed by an increase over the first half of the 21st century. In the second half of the 21st century, ozone is projected to continue increasing, level off, or even decrease depending on the latitude. Separation into partial columns above and below 20 hPa reveals that these latitudinal differences are almost completely caused by differences in the model projections of ozone in the lower stratosphere. At all latitudes, upper stratospheric ozone increases throughout the 21st century and is projected to return to 1960 levels well before the end of the century, although there is a spread among models in the dates that ozone returns to specific historical values. We find decreasing halogens and declining upper atmospheric temperatures, driven by increasing greenhouse gases, contribute almost equally to increases in upper stratospheric ozone. In the tropical lower stratosphere, an increase in upwelling causes a steady decrease in ozone through the 21st century, and total column ozone does not return to 1960 levels in most of
the models. In contrast, lower stratospheric and total column ozone in middle and high latitudes increases during the 21st century, returning to 1960 levels well before the end of the century in most models
Distorted Views of Biodiversity: Spatial and Temporal Bias in Species Occurrence Data
Boakes et al. compile and analyze a historical dataset of 170,000 bird sightings over two centuries and show how changing trends in data gathering may confound a true picture of biodiversity change
- âŠ