Human-driven land-use changes increasingly threaten biodiversity, particularly in tropical forests where both species diversity and human pressures on natural environments are high. The rapid ...conversion of tropical forests for agriculture, timber production and other uses has generated vast, human-dominated landscapes with potentially dire consequences for tropical biodiversity. Today, few truly undisturbed tropical forests exist, whereas those degraded by repeated logging and fires, as well as secondary and plantation forests, are rapidly expanding. Here we provide a global assessment of the impact of disturbance and land conversion on biodiversity in tropical forests using a meta-analysis of 138 studies. We analysed 2,220 pairwise comparisons of biodiversity values in primary forests (with little or no human disturbance) and disturbed forests. We found that biodiversity values were substantially lower in degraded forests, but that this varied considerably by geographic region, taxonomic group, ecological metric and disturbance type. Even after partly accounting for confounding colonization and succession effects due to the composition of surrounding habitats, isolation and time since disturbance, we find that most forms of forest degradation have an overwhelmingly detrimental effect on tropical biodiversity. Our results clearly indicate that when it comes to maintaining tropical biodiversity, there is no substitute for primary forests.
Accelerated muon beams have been considered for next-generation studies of high-energy lepton-antilepton collisions and neutrino oscillations. However, high-brightness muon beams have not yet been ...produced. The main challenge for muon acceleration and storage stems from the large phase-space volume occupied by the beam, derived from the muon production mechanism through the decay of pions from proton collisions. Ionization cooling is the technique proposed to decrease the muon beam phase-space volume. Here we demonstrate a clear signal of ionization cooling through the observation of transverse emittance reduction in beams that traverse lithium hydride or liquid hydrogen absorbers in the Muon Ionization Cooling Experiment (MICE). The measurement is well reproduced by the simulation of the experiment and the theoretical model. The results shown here represent a substantial advance towards the realization of muon-based facilities that could operate at the energy and intensity frontiers.
Platelet function and blood coagulation were studied in five human volunteers receiving penicillin-G in incremental doses of 1.2--48 million U/day, in six volunteers receiving ampicillin in ...incremental doses of 60--300 mg/kg/day (4--20 g/day), and in six volunteers receiving methicillin in incremental doses of 60--300 mg/kg/day. Coagulation tests remained normal in all 17 volunteers. However, ADP-induced platelet aggregation became abnormal in every subject except one receiving ampicillin and one receiving methicillin. Defective aggregation occurred with predictability with the following doses: penicillin-G, 24 million U/day; ampicillin, 300 mg/kg/day; methicillin, 300 mg/kg/day. All volunteers given penicillin-G and all given ampicillin experienced dose-related prolongation of bleeding time which did not occur with methicillin. Striking prolongation of bleeding time occurred only with penicillin-G in doses of 48 million U/day. Other tests of platelet function including clot retraction, platelet factor 3 availability, and collagen-induced or epinephrine-induced aggregation remained normal during the administration of these drugs. Measurement of intracellular adenine nucleotides revealed that the ADP and ATP content of platelets was unaffected. It appears that at least one mechanism by which the penicillin compounds alter platelet behavior is by interfering with activation of these cells by ADP.
We employ a multi-method approach to more fully explore determinants of greater than expected rural county-level increases and decreases in the proportion of working poor in four states. An ...econometric model by Anderson, Goe, and Weng (2007) using 1990 and 2000 Census data in the North Central region of the U.S. supplies the error terms to identify our outlier counties. We show that counties performing better than expected may be more self-reliant than counties performing worse than expected (Michigan), that regional attributes contribute greatly to overall performance (Ohio), that the structure of local employment patterns also influences outcomes (Missouri), while devolution of federal government and long-term commuting patterns may also affect outcomes (South Dakota). Future efforts should attempt to replicate these research strategies and may serve to inform the direction of best practice in federal data collection efforts.
One of the still open issues for the development of superconducting insertion devices is the understanding of the beam heat load. With the aim of measuring the beam heat load to a cold bore and the ...hope to gain a deeper understanding in the beam heat load mechanisms, a cold vacuum chamber for diagnostics is under construction. The following diagnostics will be implemented: i) retarding field analyzers to measure the electron energy and flux, ii) temperature sensors to measure the total heat load, iii) pressure gauges, iv) and mass spectrometers to measure the gas content. The inner vacuum chamber will be removable in order to test different geometries and materials. This will allow the installation of the cryostat in different synchrotron light sources. COLDDIAG will be built to fit in a short straight section at ANKA. A first installation at the synchrotron light source Diamond is foreseen in June 2011. Here we describe the technical design report of this device and the planned measurements with beam.
Combined intravenous infusions of ticarcillin and cefazolin given to normal volunteers resulted in a functional platelet defect which appeared to be determined primarily by the dose and duration of ...treatment with the penicillin component. No effect on soluble blood coagulation factors was evident. Acute administration of corticosteroids did not influence the prolonged bleeding times induced by extended ticarcillin infusions.
The importance of commensal microbes for human health is increasingly recognized, yet the impacts of evolutionary changes in human diet and culture on commensal microbiota remain almost unknown. Two ...of the greatest dietary shifts in human evolution involved the adoption of carbohydrate-rich Neolithic (farming) diets (beginning ∼10,000 years before the present) and the more recent advent of industrially processed flour and sugar (in ∼1850). Here, we show that calcified dental plaque (dental calculus) on ancient teeth preserves a detailed genetic record throughout this period. Data from 34 early European skeletons indicate that the transition from hunter-gatherer to farming shifted the oral microbial community to a disease-associated configuration. The composition of oral microbiota remained unexpectedly constant between Neolithic and medieval times, after which (the now ubiquitous) cariogenic bacteria became dominant, apparently during the Industrial Revolution. Modern oral microbiotic ecosystems are markedly less diverse than historic populations, which might be contributing to chronic oral (and other) disease in postindustrial lifestyles.
1. The amino-terminal peptide (1â24) of bovine serum albumin was subjected to carboxymethylation by 0.2 m bromoacetate at pH 6.8 in the presence of 0, 1, and 2 eq of copper(II) ion. The treatment ...with bromoacetate in the absence
of copper(II) caused almost quantitative carboxymethylation of the imidazole groups of the 3 histidyl residues at positions
3, 9, and 18 in the sequences. In addition, the terminal α-amino group was apparently modified. Spectral measurements on the
copper-containing complexes showed little or no effect on the copper chelation by the alkylation treatment.
2. Binding of 1 eq of copper(II) protects quantitatively the terminal α-amino group and histidyl residue 3, and appears to
reduce somewhat the reactivity of histidyl residue 18.
3. Binding of 2 eq of copper(II) also protects the components of the preferred terminal site, but, in addition, both histidyl
residues 9 and 18 are largely, and about equally, protected from alkylation. The binding of the 2nd eq therefore appears to
involve both histidyl residues, in keeping with spectral and titration results. An intramolecular chelate structure or intermolecular
chelates involving dimers or higher polymers are suggested.
4. The tetrapeptide l -aspartyl- l -threonyl- l -histidyl- l -lysine, which corresponds to the first 4 residues of peptide (1â24), was shown by titration, absorbance, and circular dichroism
measurements to form an equimolar complex with copper(II) that has substantially the properties of the complex of peptide
(1â24) containing 1 eq of copper(II) ion. Similar measurements on the equimolar complex of bovine serum albumin fill out a
continuity that is especially evident from measurements of circular dichroism.
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