Dispersal capacity and diet breadth modify the response of wild bees to habitat loss

Habitat loss poses a major threat to biodiversity, and species-specific extinction risks are inextricably linked to life-history characteristics. This relationship is still poorly documented for many functionally important taxa, and at larger continental scales. With data from five replicated field studies from three countries, we examined how species richness of wild bees varies with habitat patch size. We hypothesized that the form of this relationship is affected by body size, degree of host plant specialization and sociality. Across all species, we found a positive species–area slope (z ¼ 0.19), and species traits modified this relationship. Large-bodied generalists had a lower z value than small generalists. Contrary to predictions, small specialists had similar or slightly lower z value compared with large specialists, and small generalists also tended to be more strongly affected by habitat loss as compared with small specialists. Social bees were negatively affected by habitat loss (z ¼ 0.11) irrespective of body size. We conclude that habitat loss leads to clear shifts in the species composition of wild bee communities.

Turbulent flow at 190 m height above London during 2006-2008: A climatology and the applicability of similarity theory

Flow and turbulence above urban terrain is more complex than above rural terrain, due to the different momentum and heat transfer characteristics that are affected by the presence of buildings (e.g. pressure variations around buildings). The applicability of similarity theory (as developed over rural terrain) is tested using observations of flow from a sonic anemometer located at 190.3 m height in London, U.K. using about 6500 h of data. Turbulence statistics—dimensionless wind speed and temperature, standard deviations and correlation coefficients for momentum and heat transfer—were analysed in three ways. First, turbulence statistics were plotted as a function only of a local stability parameter z/Λ (where Λ is the local Obukhov length and z is the height above ground); the σ_i/u_* values (i = u, v, w) for neutral conditions are 2.3, 1.85 and 1.35 respectively, similar to canonical values. Second, analysis of urban mixed-layer formulations during daytime convective conditions over London was undertaken, showing that atmospheric turbulence at high altitude over large cities might not behave dissimilarly from that over rural terrain. Third, correlation coefficients for heat and momentum were analyzed with respect to local stability. The results give confidence in using the framework of local similarity for turbulence measured over London, and perhaps other cities. However, the following caveats for our data are worth noting: (i) the terrain is reasonably flat, (ii) building heights vary little over a large area, and (iii) the sensor height is above the mean roughness sublayer depth.

Omega-3 fatty acids, cardiovascular disease and stability of atherosclerotic plaques

Long-chain n-3 polyunsaturated fatty acids are found in oily fish and in fish oils and similar preparations. Substantial evidence from epidemiological and case-control studies indicates that consumption of fish, oily fish and long-chain n-3 fatty acids reduces risk of cardiovascular mortality. Secondary prevention studies using long-chain n-3 fatty acids in patients post-myocardial infarction have shown a reduction in total and cardiovascular mortality with an especially potent effect on sudden death. Long-chain n-3 fatty acids have been shown to beneficially modify a range of cardiovascular risk factors, which may result in primary cardiovascular prevention. However, reduced non-fatal and fatal events and a reduction in sudden death probably involve other mechanisms. Reduced thrombosis following long-chain n-3 fatty acids may play a role. A decrease in arrhythmias is a favoured mechanism of action of long-chain n-3 fatty acids and is supported by cell culture and animal studies. However human trials using implantable cardiac defibrillators have produced inconsistent findings and a recent meta-analysis does not support this mechanism of action. An alternative mechanism of action may be stabilisation of atherosclerotic plaques by long-chain n-3 fatty acids. This is suggested by one published human study which showed that incorporation of long-chain n-3 fatty acids into plaques collected at carotid endarterectomy resulted in fewer macrophages in the plaque and a morphology indicative of increased stability. These findings are supported from observations in an animal model and suggest that the primary effect of long-chain n-3 fatty acids might be on macrophages within the plaque.

Simultaneous observations of reconnection pulses at Cluster and their effects on the cusp aurora seen at Chinese Yellow River Station

While the Cluster spacecraft were located near the high-latitude magnetopause, between 10:10 and 10:40 UT on 16 January 2004, three typical flux transfer event (FTE) signatures were observed. During this interval, simultaneous and conjugated all-sky camera measurements, recorded at Yellow River Station, Svalbard, are available at 630.0 and 557.7nm that show poleward-moving auroral forms (PMAFs), consistent with magnetic reconnection at dayside magnetopause. Simultaneous FTEs seen at the magnetopause mainly move northward, but having duskward (eastward) and tailward velocity components, roughly consistent with the observed direction of motion of the PMAFs in all-sky images. Between the PMAFs meridional keograms, extracted from the all-sky images, show intervals of lower intensity aurora which migrate equatorward just before the PMAFs intensify. This is strong evidence for an equatorward eroding and poleward moving open-closed boundary (OCB) associated with a variable magnetopause reconnection rate under variable IMF conditions. From the durations of the PMAFs we infer that the evolution time of FTEs is 5-11 minutes from its origin on magnetopause to its addition to the polar cap.

Decadal-scale rainfall variability in Ethiopia recorded in an annually laminated, Holocene-age, stalagmite

An annually laminated, uranium-series dated, Holocene stalagmite from southeast Ethiopia has been analysed for growth rate and δ13C and δ18O variations at annual to biennial resolution, in order to provide the first long duration proxy record of decadal-scale rainfall variability in this climatically sensitive region. Our study site (10°N) is climatically influenced by both summer (June—August) and spring (March—May) rainfall caused by the annual movement of the Inter-Tropical Convergence Zone (ITCZ) and modulated by large-scale anomalies in the atmospheric circulation and in ocean temperatures. Here we show that stalagmite growth, episodic throughout the last 7800 years, demonstrates decadal-scale (8—25 yr) variability in both growth rate and δ 18O. A hydrological model was employed and indicates that this decadal variability is due to variations in the relative amounts of rainfall in the two rain seasons. Our record, unique in its combination of length (a total of ~1000 years), annual chronology and high resolution δ18O, shows for the first time that such decadal-scale variability in rainfall in this region has occurred through the Holocene, which implies persistent decadal-scale variability for the large-scale atmospheric and oceanic driving factors.

Initial results from Phase 2 of the international urban energy balance model comparison

Urban land surface schemes have been developed to model the distinct features of the urban surface and the associated energy exchange processes. These models have been developed for a range of purposes and make different assumptions related to the inclusion and representation of the relevant processes. Here, the first results of Phase 2 from an international comparison project to evaluate 32 urban land surface schemes are presented. This is the first large-scale systematic evaluation of these models. In four stages, participants were given increasingly detailed information about an urban site for which urban fluxes were directly observed. At each stage, each group returned their models' calculated surface energy balance fluxes. Wide variations are evident in the performance of the models for individual fluxes. No individual model performs best for all fluxes. Providing additional information about the surface generally results in better performance. However, there is clear evidence that poor choice of parameter values can cause a large drop in performance for models that otherwise perform well. As many models do not perform well across all fluxes, there is need for caution in their application, and users should be aware of the implications for applications and decision making.

Peptides generated ex vivo from serum proteins by tumor-specific exopeptidases are not useful biomarkers in ovarian cancer

BACKGROUND: The serum peptidome may be a valuable source of diagnostic cancer biomarkers. Previous mass spectrometry (MS) studies have suggested that groups of related peptides discriminatory for different cancer types are generated ex vivo from abundant serum proteins by tumor-specific exopeptidases. We tested 2 complementary serum profiling strategies to see if similar peptides could be found that discriminate ovarian cancer from benign cases and healthy controls. METHODS: We subjected identically collected and processed serum samples from healthy volunteers and patients to automated polypeptide extraction on octadecylsilane-coated magnetic beads and separately on ZipTips before MALDI-TOF MS profiling at 2 centers. The 2 platforms were compared and case control profiling data analyzed to find altered MS peak intensities. We tested models built from training datasets for both methods for their ability to classify a blinded test set. RESULTS: Both profiling platforms had CVs of approximately 15% and could be applied for high-throughput analysis of clinical samples. The 2 methods generated overlapping peptide profiles, with some differences in peak intensity in different mass regions. In cross-validation, models from training data gave diagnostic accuracies up to 87% for discriminating malignant ovarian cancer from healthy controls and up to 81% for discriminating malignant from benign samples. Diagnostic accuracies up to 71% (malignant vs healthy) and up to 65% (malignant vs benign) were obtained when the models were validated on the blinded test set. CONCLUSIONS: For ovarian cancer, altered MALDI-TOF MS peptide profiles alone cannot be used for accurate diagnoses.

Incorporation of cis-9,trans-11 or trans-10,cis-12 conjugated linoleic acid into plasma and cellular lipids in healthy men

This study investigated the incorporation of cis-9,trans-11 conjugated linoleic acid (c9,t11 CLA) and trans-10,cis-12-CLA (t10,c12 CLA) into plasma and peripheral blood mononuclear cell (PBMC) lipids when consumed as supplements highly enriched in these isomers. Healthy men (n = 49, age 31 +/- 8 years) consumed one, two, and four capsules containing similar to600 mg of either c9,t11 CIA or t10,c12 CLA per capsule for sequential 8 week periods followed by a 6 week washout before consuming the alternative isomer. Both isomers were incorporated in a dosedependent manner into plasma phosphatidylcholine (PC) (c9,t11 CLA r = 0.779, t10,c12 CLA r = 0.738; P < 0.0001) and cholesteryl ester (CE) (c9,t11 CLA r = 0.706, t10,c12 CLA r = 0.788; P < 0.0001). Only t10,c12 CLA was enriched in plasma nonesterified fatty acids. Both c9,t11 CIA and t10,c12 CLA were incorporated linearly into PBMC total lipids (r = 0.285 and r = 0.273, respectively; P < 0.0005). The highest concentrations of c9,t11 CLA and t10,c12 CLA in PBMC lipids were 3- to 4-fold lower than those in plasma PC and CE. These data suggest that the level of intake is a major determinant of plasma and PBMC CLA content, although PBMCs appear to incorporate both CLA isomers less readily.

Fragmentation or creative diversity? Options in the provision of land management advisory services

Rural land managers need access to sound advice and information to respond to pressures from environmental regulations, declining farm incomes, changing patterns in international trade and new institutional arrangements within the domestic food chain. Governments have cut back their provision of advisory services but need more than ever to influence land managers' decisions to achieve a growing array of policy objectives: The paper develops a conceptual framework for analysing advisory services and concludes, through a review of sixteen case studies, that the needs of both governments and land managers can be met by a diverse mixture of private and public sector provision. (C) 2003 Elsevier Ltd. All rights reserved.