3,385 research outputs found
NMFS / Interagency Working Group Evaluation of CITES Criteria and Guidelines.
EXECUTIVE SUMMARY: At present, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) criteria used to assess whether a population qualifies for inclusion in the CITES Appendices relate to (A) size of the population, (B) area of distribution of the population, and (C) declines in the size of the population. Numeric guidelines are provided as indicators of a small population (less than 5,000 individuals), a small subpopulation (less than 500 individuals), a restricted area of distribution for a population (less than 10,000 km2), a restricted area of distribution for a subpopula-tion (less than 500 km2), a high rate of decline (a decrease of 50% or more in total within 5 years or two generations whichever is longer or, for a small wild population, a decline of 20% or more in total within ten years or three generations whichever is longer), large fluctuations (population size or area of distribution varies widely, rapidly and frequently, with a variation greater than one order of magnitude), and a short-term fluctuation (one of two years or less).
The Working Group discussed several broad issues of relevance to the CITES criteria and guidelines. These included the importance of the historical extent of decline versus the recent rate of decline; the utility and validity of incorporating relative population productivity into decline criteria; the utility of absolute numbers for defining small populations or small areas; the appropriateness of generation times as time frames for examining declines; the importance of the magnitude and frequency of fluctuations as factors affecting risk of extinction; and the overall utility of numeric thresh-olds or guidelines
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Estimating forecast error covariances for strongly coupled atmosphere-ocean 4D-Var data assimilation
Strongly coupled data assimilation emulates the real world pairing of the atmosphere and ocean by solving the assimilation problem in terms of a single combined atmosphere-ocean state. A significant challenge in strongly coupled variational atmosphere-ocean data assimilation is a priori specification of the cross-covariances between the errors in the atmosphere and ocean model forecasts.
These covariances must capture the correct physical structure of interactions across the air-sea interface as well as the different scales of evolution in the atmosphere and ocean; if prescribed correctly, they will allow observations in one medium to improve the analysis in the other.
Here we investigate the nature and structure of atmosphere-ocean forecast error cross-correlations using an idealised strongly coupled single-column atmosphere-ocean 4D-Var assimilation system. We present results from a set of identical twin experiments that use an ensemble of coupled 4D-Var assimilations to derive estimates of the atmosphere-ocean error cross-correlations. Our results show significant variation in the strength and structure of cross-correlations in the atmosphere-ocean boundary layer between summer and winter and between day and night. These differences provide a valuable insight into the nature of coupled atmosphere-ocean correlations for different seasons and points in the diurnal cycle
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The role of cross-domain error correlations in strongly coupled 4D-Var atmosphere-ocean data assimilation
Strongly coupled atmosphere-ocean data assimilation offers the ability to improve information exchange across the modelled air-sea interface by enabling observations in one domain to have a direct influence on the analysis in the other. For incremental 4D-Var assimilation a strongly coupled approach enables both domains to be updated at the beginning of the assimilation window, whether they are observed or not, and is hence more likely to produce consistent initial model states. This is made possible by
the explicit inclusion of cross-domain forecast error covariance information in the coupled forecast error covariance matrix.
In this study we use an idealised 1D single column coupled
atmosphere-ocean model to examine the extent to which explicit cross-domain forecast error covariances play a role in shaping the coupled analysis increments compared to those implicitly generated in the inner-loop of the incremental formulation of the 4D-Var algorithm. This is done via a set of single observation experiments with and without initial cross-domain forecast error covariances prescribed. Using single observations allows us to
obtain explicit expressions for the atmosphere and ocean analysis updates, separating out the individual effects of the explicitly prescribed and implicitly generated cross-domain covariances. Our experiments show that when only one domain is observed,including explicit cross-domain error covariances allows more consistent adjustment of the unobserved domain. Neglecting the cross-domain terms and relying solely on the covariances implicitly generated by the coupled tangent linear and adjoint models restricts the ability of the covariance matrix to impose balance between the two domains. In this case the coupling is essentially one-way; the update to the observed domain is
independent of the unobserved domain and so is likely to produce atmosphere and ocean updates that are inconsistent with one another. As we show, this has important consequences for the balance of the coupled analysis state
Towards Universal Screening for Colon Cancer: A Cheap, Reliable, Noninvasive Test Using Gene Expression Analysis of Rectal Swabs
Though colon cancer is the second leading cause of cancer deaths in the US, it is entirely preventable through early screening to detect and remove adenomatous polyps. Colonoscopy has long been regarded as the “gold standard” but is expensive, invasive, and uncomfortable, and only about half those considered at risk for colon cancer currently submit to colonoscopy or to less reliable alternatives such as fecal occult blood test. Here we describe the use of gene expression analysis to detect altered expression of certain genes associated with not only colon cancer but also polyps. The analysis can be performed on rectal swabs, with specimens provided in a routine doctor's office visit. The existence of this cheap and simple test, together with an active program to encourage individuals to submit to screening, could help eradicate colon cancer
County Agent Views About Facilitating Public Education and Discussion of Genetic Engineering Use in Agriculture
We conducted seven focus groups with Extension agents from three northeast states in Spring 2000 to learn what agents knew about genetic engineering (GE) applications in agriculture, their view of Extension\u27s role in public discussion and education, and the training needed to assume such a role. While participating agents together knew a fair amount about their target audiences\u27 perceptions of GE, they felt unprepared to deal with the challenges of public issues education in light of the current public debate, the publics\u27 low science literacy, and their own science background. Their expressed training needs reflected these challenges
Teachers Learn About ADHD on the Web: An Online Graduate Special Education Course
This is the publisher's version, also found here: www.sped.orgDescribes several possibilities for using Internet-based applications to enhance teacher preparation to better serve students with attention-deficit/hyperactivity disorder (ADHD). Features of the Web-enhanced course, The Learner with ADHD which offers a general introduction to characteristics, treatment and education of students with ADHD. INSETS: Perspectives on distance learning; WebCT-an online course tool
The Obesity Paradox and Cardiorespiratory Fitness
Cardiorespiratory fitness as an explanation for the obesity paradox warrants further examination. We evaluated independent and joint associations of cardiorespiratory fitness and adiposity with all-cause mortality in 811 middle-aged (age, 53.3 ± 7.2 years) male never smokers without documented cardiopulmonary disease or diabetes from the Veterans Exercise Testing Study (VETS). Cardiorespiratory fitness was quantified in metabolic equivalents (METs) using final treadmill speed and grade achieved on a maximal exercise test. Subjects were grouped for analysis by METs: unfit (lowest third) and fit (upper two-thirds); and by body mass index (kg/m2): nonobese (18.5−29.9) and obese (≥30.0). Associations of baseline fitness and adiposity measures with all-cause mortality were determined by Cox proportional hazards analysis adjusted for age, ethnicity, hypertension, hypercholesterolemia, family history of coronary artery disease, and cardiovascular medication use. In multivariate analysis, mortality risk for obese/fit men did not differ significantly from the nonobese/fit reference group. However, compared to the reference group, nonobese and obese unfit men were 2.2 (P = 0.01) and 1.9 (P = 0.03) times more likely to die, respectively. Cardiorespiratory fitness altered the obesity paradox such that mortality risk was lower for both obese and nonobese men who were fit
Word service for grades one through six
Thesis (Ed.M.)--Boston Universit
New Evidence for Efficient Collisionless Heating of Electrons at the Reverse Shock of a Young Supernova Remnant
Although collisionless shocks are ubiquitous in astrophysics, certain key
aspects of them are not well understood. In particular, the process known as
collisionless electron heating, whereby electrons are rapidly energized at the
shock front, is one of the main open issues in shock physics. Here we present
the first clear evidence for efficient collisionless electron heating at the
reverse shock of Tycho's supernova remnant (SNR), revealed by Fe-K diagnostics
using high-quality X-ray data obtained by the Suzaku satellite. We detect
K-beta (3p->1s) fluorescence emission from low-ionization Fe ejecta excited by
energetic thermal electrons at the reverse shock front, which peaks at a
smaller radius than Fe K-alpha (2p->1s) emission dominated by a relatively
highly-ionized component. Comparison with our hydrodynamical simulations
implies instantaneous electron heating to a temperature 1000 times higher than
expected from Coulomb collisions alone. The unique environment of the reverse
shock, which is propagating with a high Mach number into rarefied ejecta with a
low magnetic field strength, puts strong constraints on the physical mechanism
responsible for this heating, and favors a cross-shock potential created by
charge deflection at the shock front. Our sensitive observation also reveals
that the reverse shock radius of this SNR is about 10% smaller than the
previous measurement using the Fe K-alpha morphology from the Chandra
observations. Since strong Fe K-beta fluorescence is expected only from
low-ionization plasma where Fe ions still have many 3p electrons, this feature
is key to diagnosing the plasma state and distribution of the immediate
postshock ejecta in a young SNR.Comment: 7 pages, 9 figures, resubmitted to ApJ with minor changes following
the referee repor
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