2,913 research outputs found

    Underestimates of US emissions and global implications for industrializing animal agriculture

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    Keywords: GHG emissions. Industrial-scale food animal production. Extensive animal agriculture systems. Highlights of this report or guidance memo: *Scientific literature on greenhouse gas emissions of various forms of animal agriculture systems are synthesized. *Explains the complexities of models used to generate estimates of GHGs in these scientific literature, and the reasons why they are not very robust and they contain errors that often go unreported. *Points out that high-quality measurements that do exist consistently demonstrate that industrial animal agriculture's emissions are actually higher than typically estimated. Therefore the claim held by many experts and policy-makers that intensifying animal agriculture significantly limits global GHG emissions is unjustified. *Cautions about not jumping to the conclusion that extensive, pastoral systems is the perfect answer

    Nationwide shift to grass-fed beef requires larger cattle population

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    In the US, there is growing interest in producing more beef from cattle raised in exclusively pasture-based systems, rather than grain-finishing feedlot systems, due to the perception that it is more environmentally sustainable. Yet existing understanding of the environmental impacts of exclusively pasture-based systems is limited by a lack of clarity about cattle herd dynamics. We model a nationwide transition from grain- to grass-finishing systems using demographics of present-day beef cattle. In order to produce the same quantity of beef as the present-day system, we find that a nationwide shift to exclusively grass-fed beef would require increasing the national cattle herd from 77 to 100 million cattle, an increase of 30%. We also find that the current pastureland grass resource can support only 27% of the current beef supply (27 million cattle), an amount 30% smaller than prior estimates. If grass-fed systems include cropland-raised forage, a definition that conforms to typical grass-fed certifications, these supplemental feeds can support an additional 34 million cattle to produce up to 61% of the current beef supply. Given the potential of forage feed croplands to compete with human food crop production, more work is required to determine optimal agricultural land uses. Future US demand in an entirely grass-and forage-raised beef scenario can only be met domestically if beef consumption is reduced, due to higher prices or other factors. If beef consumption is not reduced and is instead satisfied by greater imports of grass-fed beef, a switch to purely grass-fed systems would likely result in higher environmental costs, including higher overall methane emissions. Thus, only reductions in beef consumption can guarantee reductions in the environmental impact of US food systems.ISSN:1748-9326ISSN:1748-931

    Calyceal diverticula: a comprehensive review

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    Calyceal diverticula are rare outpouchings of the upper collecting system that likely have a congenital origin. Stones can be found in up to 50% of calyceal diverticula, although, over the combined reported series, 96% of patients presented with stones. Diagnosis is best made by intravenous urography or computed tomography urogram. Shock wave lithotripsy (SWL) is an option for first-line therapy in patients with stone-bearing diverticula that have radiologically patent necks in mid- to upper-pole diverticula and small stone burdens. Stone-free rates are the lowest with SWL, although patients report being asymptomatic following therapy in up to 75% of cases with extended follow-up. Ureteroscopy (URS) is best suited for management of anteriorly located mid- to upperpole diverticular stones. Drawbacks to URS include difficulty in identifying the ostium and low rate of obliteration. Percutaneous management is best used in posteriorly located mid- to lower-pole stones, and offers the ability to directly ablate the diverticulum. Percutaneous nephrolithotomy remains effective in the management of upperpole diverticula, but carries the risk of pulmonary complications unless subcostal access strategies such as triangulation or renal displacement are used. Laparoscopic surgery provides definitive management, but should be reserved for cases with large stones in anteriorly located diverticula with thin overlying parenchyma, and cases that are refractory to other treatment. This article reviews the current theories on the pathogenesis of calyceal diverticula. The current classification is examined in addition to the current diagnostic methods. Here we summarize an extensive review of the literature on the outcomes of the different treatment approaches

    The challenge of policy coordination for sustainable sociotechnical transitions: the case of the zero-carbon homes agenda in England

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    Emerging in recent research on sociotechnical transitions towards a low-carbon economy is the question of the extent to which such transitions require centralised, intentional coordination by government. Drawing from Hayek's conceptualisation of coordination, I evaluate the effectiveness of policy for low-carbon and zero-carbon homes in England. A detailed analysis is presented of how policy makers address complex choices and trade-offs as well as significant uncertainty. Particular attention is given to those policy decisions which are widely agreed by stakeholders to cause distortive effects. The focus here on the impacts of policy definition and delivery in terms of multiple evaluative criteria can complement and enrich the more process-orientated cross-sector and multilevel analyses that predominate in existing research on policy coordination. Furthermore, the coordination problems identified yield further insights into the actual and potential effectiveness of policy processes in shaping complex sociotechnical transitions

    Characterization of s-SWCNT/PF-PD Dispersions and Networks

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    Single-Walled Carbon Nanotubes (SWCNTs) are being investigated for their use in a wide variety of renewable energy applications. Their unique physical properties contribute to desirable traits such as a high carrier mobility, strong optical absorption and tunable electronic band gap. Unfortunately, due to variability in certain parameters, SWCNTs are limited in their application. The major drawback is that SWCNTs are variable in size and type and typical synthetic methods are not selective. As a result, selective methods must be developed in order to sort these tubes and extract those which are desirable for a particular application. Though there are several enrichment strategies, polymer-wrapping was used to select semiconducting SWCNTs in this research. Some issues with polymer-wrapping include inability to remove polymer post-enrichment as well as difficulty re-dispersing SWCNTs post polymer removal. Polymer removal is necessary for certain applications and the presence of excess polymer in SWCNTs can decrease their efficiency. To address the first issue, a removable polymer, PF-PD was used in the dispersion making process. The second issue of re-dispersal was discovered to be specific to a particular batch of PF-PD and was combatted by altering the polymer removal step from a centrifuge run to a TFA vapor treatment. PF-PD is loosely linked by imine bonds which are degraded by the TFA and make it easier to remove. This process does require some refining, however, since a significant percentage of SWCNTs are lost during the treatment. Several other mini experiments were conducted throughout the course of this research to contribute to a better understanding of the quality of dispersions that could be made using PF-PD with unpurified SWCNTs. The results of these experiments are inconclusive but do lead to the need for further and more detailed research on SWCNTs

    Impact d'une décharge de déchets ménagers sur l'environnement

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    The Hamburg/ESO R-process Enhanced Star survey (HERES) IV. Detailed abundance analysis and age dating of the strongly r-process enhanced stars CS 29491-069 and HE 1219-0312

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    We report on a detailed abundance analysis of two strongly r-process enhanced, very metal-poor stars newly discovered in the HERES project, CS 29491-069 ([Fe/H]=-2.51, [r/Fe]=+1.1) and HE 1219-0312 ([Fe/H]=-2.96, [r/Fe]=+1.5). The analysis is based on high-quality VLT/UVES spectra and MARCS model atmospheres. We detect lines of 15 heavy elements in the spectrum of CS 29491-069, and 18 in HE 1219-0312; in both cases including the Th II 4019 {\AA} line. The heavy-element abundance patterns of these two stars are mostly well-matched to scaled solar residual abundances not formed by the s-process. We also compare the observed pattern with recent high-entropy wind (HEW) calculations, which assume core-collapse supernovae of massive stars as the astrophysical environment for the r-process, and find good agreement for most lanthanides. The abundance ratios of the lighter elements strontium, yttrium, and zirconium, which are presumably not formed by the main r-process, are reproduced well by the model. Radioactive dating for CS 29491-069 with the observed thorium and rare-earth element abundance pairs results in an average age of 9.5 Gyr, when based on solar r-process residuals, and 17.6 Gyr, when using HEW model predictions. Chronometry seems to fail in the case of HE 1219-0312, resulting in a negative age due to its high thorium abundance. HE 1219-0312 could therefore exhibit an overabundance of the heaviest elements, which is sometimes called an "actinide boost"

    Hubble Space Telescope Transmission Spectroscopy of the Exoplanet HD 189733b: High-altitude atmospheric haze in the optical and near-UV with STIS

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    We present Hubble Space Telescope optical and near-ultraviolet transmission spectra of the transiting hot-Jupiter HD189733b, taken with the repaired Space Telescope Imaging Spectrograph (STIS) instrument. The resulting spectra cover the range 2900-5700 Ang and reach per-exposure signal-to-noise levels greater than 11,000 within a 500 Ang bandwidth. We used time series spectra obtained during two transit events to determine the wavelength dependance of the planetary radius and measure the exoplanet's atmospheric transmission spectrum for the first time over this wavelength range. Our measurements, in conjunction with existing HST spectra, now provide a broadband transmission spectrum covering the full optical regime. The STIS data also shows unambiguous evidence of a large occulted stellar spot during one of our transit events, which we use to place constraints on the characteristics of the K dwarf's stellar spots, estimating spot temperatures around Teff~4250 K. With contemporaneous ground-based photometric monitoring of the stellar variability, we also measure the correlation between the stellar activity level and transit-measured planet-to-star radius contrast, which is in good agreement with predictions. We find a planetary transmission spectrum in good agreement with that of Rayleigh scattering from a high-altitude atmospheric haze as previously found from HST ACS camera. The high-altitude haze is now found to cover the entire optical regime and is well characterised by Rayleigh scattering. These findings suggest that haze may be a globally dominant atmospheric feature of the planet which would result in a high optical albedo at shorter optical wavelengths.Comment: 14 pages, 14 figures, 4 tables, accepted to MNRAS, revised version has minor change

    Altered inflammasome machinery as a key player in the perpetuation of Rett syndrome oxinflammation

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    Rett syndrome (RTT) is a progressive neurodevelopmental disorder mainly caused by mutations in the X-linked MECP2 gene. RTT patients show multisystem disturbances associated with an oxinflammatory status. Inflammasomes are multi-protein complexes, responsible for host immune responses against pathogen infections and redox-related cellular stress. Assembly of NLRP3/ASC inflammasome triggers pro-caspase-1 activation, thus, resulting in IL-1β and IL-18 maturation. However, an aberrant activation of inflammasome system has been implicated in several human diseases. Our aim was to investigate the possible role of inflammasome in the chronic subclinical inflammatory condition typical of RTT, by analyzing this complex in basal and lipopolysaccharide (LPS)+ATP-stimulated primary fibroblasts, as well as in serum from RTT patients and healthy volunteers. RTT cells showed increased levels of nuclear p65 and ASC proteins, pro-IL-1β mRNA, and NLRP3/ASC interaction in basal condition, without any further response upon the LPS + ATP stimuli. Moreover, augmented levels of circulating ASC and IL-18 proteins were found in serum of RTT patients, which are likely able to amplify the inflammatory response. Taken together, our findings suggest that RTT patients exhibited a challenged inflammasome machinery at cellular and systemic level, which may contribute to the subclinical inflammatory state feedback observed in this pathology

    Trouble in Paradise - A disabled person's right to the satisfaction of a self-defined need:Some conceptual and practical problems

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    This paper questions the usefulness of the rights-based approach to ameliorating the social situation of disabled people in Britain and advances two criticisms. First, that rights and self-de? ned needs have been under-theorised by disability theorists to the extent that they have insuf? ciently appreciated the problems that these approaches pose. The paper suggests that rights to appropriate resources to satisfy self-de? ned needs will generate vast numbers of competing rights claims and that the resulting tendency of rights to con? ict has been under-appreciated. Secondly, that there has been little consideration of how these con? icts might be reconciled. The ? rst two sections of the paper look at the concepts of ascribed and self-de? ned needs, respectively, whilst the ? nal one looks at some of the problems of the rights approach and some of the dif? culties of making self-de? ned need the basis of rights claims
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