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The ways in which productivity, stability, population interactions, and community structure are regulated in ecosystems have been a central focus of ecology for over a century. At large spatial scales, major insights into these dynamics have been principally derived from analyses of changes induced from hunting, harvesting, and agricultural practices – so-called “natural experiments.” In terrestrial ecosystems estimates of the fraction of land transformed or degraded by human activity fall within the range of 39 to 75% (Vitousek et al., 1997; Ellis et al., 2010). Equally profound is the reality that up to 75% of the global oceans and in particular the continental shelf, transitional slope water areas, and reef habitats have been strongly impacted by human activity (Halpern et al., 2008).
One of the most widely studied human impacts has been the over-exploitation of large-bodied species. Berger et al. (2001) estimated that the spatial distribution of large mammalian carnivores that once played a dominant role in terrestrial ecosystems has declined by 95–99%. In the global oceans large predatory fish biomass may be as low as 10% of pre-industrial levels (Myers and Worm, 2003). These changes have created a vertical compaction and blunting of the trophic pyramid (Duffy, 2003; Chapter 14, this volume). On a global scale, these losses are attributable to a positive association between body size and sensitivity to population declines experienced by larger species which exhibit a greater susceptibility to decline or collapse as a consequence of their lower population densities, greater times to maturity, lower clutch sizes, and larger home ranges (Schipper et al., 2008). This reduction in the abundance of apex predators has led to abnormally high densities of their former prey in a wide range of ecosystems, which has, in turn, resulted in sometimes catastrophic changes in the ecosystems occupied. This has led some to conclude that large-bodied species are essential to the maintenance of ecosystem structure and stability (Hildrew et al., 2007; Estes et al., 2011).
We present the results of an approximately 6 100 deg2 104–196 MHz radio sky survey performed with the Murchison Widefield Array during instrument commissioning between 2012 September and 2012 December: the MWACS. The data were taken as meridian drift scans with two different 32-antenna sub-arrays that were available during the commissioning period. The survey covers approximately 20.5 h < RA < 8.5 h, − 58° < Dec < −14°over three frequency bands centred on 119, 150 and 180 MHz, with image resolutions of 6–3 arcmin. The catalogue has 3 arcmin angular resolution and a typical noise level of 40 mJy beam− 1, with reduced sensitivity near the field boundaries and bright sources. We describe the data reduction strategy, based upon mosaicked snapshots, flux density calibration, and source-finding method. We present a catalogue of flux density and spectral index measurements for 14 110 sources, extracted from the mosaic, 1 247 of which are sub-components of complexes of sources.
In many developing countries, people rely on natural resources for subsistence and cash income. The trade ban on species listed as critically endangered by the International Union for the Conservation of Nature (IUCN) Red List may be counter-productive, as increasing the rarity and thus price of these species acts as a stimulus to illegal markets rather than a deterrent. Since illegal markets cannot have legal property rights, there is no basis for any form of sustainable harvesting based on property rights. The Malagsy radiated tortoise (Astrochelys radiata) is an example of a species that is threatened by domestic and international trade; legalizing international trade could, under certain circumstances, provide financial incentives that might effectively reduce the domestic trade and subsistence harvest of this animal. This paper argues this critically-endangered species may be more effectively conserved by assigning trading rights to local communities, rather than demanding a trade ban that cannot be enforced successfully.
Dietary modification may affect inflammatory processes and protect against chronic disease. In the present study, we examined the relationship between dietary patterns, circulating carotenoid and tocopherol concentrations, and biomarkers of chronic low-grade systemic inflammation in a 10-year longitudinal study of Scottish postmenopausal women. Diet was assessed by FFQ during 1997–2000 (n 3237, mean age 54·8 (sd 2·2) years). Participants (n 2130, mean age 66·0 (sd 2·2) years) returned during 2007–11 for follow-up. Diet was assessed by FFQ (n 1682) and blood was collected for the analysis of serum high-sensitivity C-reactive protein (hs-CRP), IL-6, serum amyloid A, E-selectin, lipid profile and dietary biomarkers (carotenoids, tocopherols and retinol). Dietary pattern and dietary biomarker (serum carotenoid) components were generated by principal components analysis. A past ‘prudent’ dietary pattern predicted serum concentrations of hs-CRP and IL-6 (which decreased across the quintiles of the dietary pattern; P= 0·002 and P= 0·001, respectively; ANCOVA). Contemporary dietary patterns were also associated with inflammatory biomarkers. The concentrations of hs-CRP and IL-6 decreased across the quintiles of the ‘prudent’ dietary pattern (P= 0·030 and P= 0·006, respectively). hs-CRP concentration increased across the quintiles of a ‘meat-dominated’ dietary pattern (P= 0·001). Inflammatory biomarker concentrations decreased markedly across the quintiles of carotenoid component score (P< 0·001 for hs-CRP and IL-6, and P= 0·016 for E-selectin; ANCOVA). Prudent dietary pattern and carotenoid component scores were negatively associated with serum hs-CRP concentration (unstandardised β for prudent component: − 0·053, 95 % CI − 0·102, − 0·003; carotenoid component: − 0·183, 95 % CI − 0·233, − 0·134) independent of study covariates. A prudent dietary pattern (which reflects a diet high in the intakes of fish, yogurt, pulses, rice, pasta and wine, in addition to fruit and vegetable consumption) and a serum carotenoid profile characteristic of a fruit and vegetable-rich diet are associated with lower concentrations of intermediary markers that are indicative of CVD risk reduction.
This study investigated the effects of different strategies for feeding supplements to grazing dairy cows on the proportions of fatty acids in milk. Two hundred and sixteen cows were fed supplementary grain and forage according to one of 3 different strategies; (1) Control: cows grazed perennial ryegrass pasture (14 kg dry matter/d) supplemented with milled barley grain fed in the milking parlour and pasture silage offered in the paddock; (2) Partial mixed ration 1 (PMR1): same pasture allotment and supplement as Control strategy, but the supplements presented as a mixed ration after each milking in feedpad, and; (3) Partial mixed ration 2 (PMR2): same pasture allotment, supplemented with a mixed ration of milled barley grain, alfalfa hay, corn silage and crushed corn grain fed in a feedpad. Within each strategy, cows were assigned to receive either 6, 8, 10 or 12 kg dry matter supplement/cow per d. Milk fatty acid proportions from cows fed Control and PMR1 strategies were similar and different from those fed PMR2, particularly at 10 to 12 kg dry matter supplement/cow per d. The reduction in milk fat yield and concentration in cows fed high amounts of supplement as Control and PMR1 was coincident with 4 × increase in 10t-18:1 proportion. The composition of the partial mixed ration (PMR) and the amount offered affected milk fatty acid proportions and milk fat content, however, the method of supplementation did not.
Significant new opportunities for astrophysics and cosmology have been identified at low radio frequencies. The Murchison Widefield Array is the first telescope in the southern hemisphere designed specifically to explore the low-frequency astronomical sky between 80 and 300 MHz with arcminute angular resolution and high survey efficiency. The telescope will enable new advances along four key science themes, including searching for redshifted 21-cm emission from the EoR in the early Universe; Galactic and extragalactic all-sky southern hemisphere surveys; time-domain astrophysics; and solar, heliospheric, and ionospheric science and space weather. The Murchison Widefield Array is located in Western Australia at the site of the planned Square Kilometre Array (SKA) low-band telescope and is the only low-frequency SKA precursor facility. In this paper, we review the performance properties of the Murchison Widefield Array and describe its primary scientific objectives.
Assessments of infectious disease spread in hospitals seldom account for interfacility patient sharing. This is particularly important for pathogens with prolonged incubation periods or carrier states.
We quantified patient sharing among all 32 hospitals in Orange County (OC), California, using hospital discharge data. Same-day transfers between hospitals were considered “direct” transfers, and events in which patients were shared between hospitals after an intervening stay at home or elsewhere were considered “indirect” patient-sharing events. We assessed the frequency of readmissions to another OC hospital within various time points from discharge and examined interhospital sharing of patients with Clostridium difficile infection.
In 2005, OC hospitals had 319,918 admissions. Twenty-nine percent of patients were admitted at least twice, with a median interval between discharge and readmission of 53 days. Of the patients with 2 or more admissions, 75% were admitted to more than 1 hospital. Ninety-four percent of interhospital patient sharing occurred indirectly. When we used 10 shared patients as a measure of potential interhospital exposure, 6 (19%) of 32 hospitals “exposed” more than 50% of all OC hospitals within 6 months, and 17 (53%) exposed more than 50% within 12 months. Hospitals shared 1 or more patient with a median of 28 other hospitals. When we evaluated patients with C. difficile infection, 25% were readmitted within 12 weeks; 41% were readmitted to different hospitals, and less than 30% of these readmissions were direct transfers.
In a large metropolitan county, interhospital patient sharing was a potential avenue for transmission of infectious agents. Indirect sharing with an intervening stay at home or elsewhere composed the bulk of potential exposures and occurred unbeknownst to hospitals.