6,137 research outputs found

    The Prevalence of Carbon-13 in Respiratory Carbon Dioxide As an Indicator of the Type of Endogenous Substrate. The change from lipid to carbohydrate during the respiratory rise in potato slices

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    Isotope discrimination is a common feature of biosynthesis in nature, with the result that different classes of carbon compounds frequently display different 13C/12C ratios. The 13C/12C ratio of lipid in potato tuber tissue is considerably lower than that for starch or protein. We have collected respiratory CO2 from potato discs in successive periods through 24 hr from the time of cutting—an interval in which the respiration rate rises 3–5-fold. The 13C/12C ratio of the evolved CO2 was determined for each period, and compared with the 13C/12C ratios of the major tissue metabolites. In the first hours the carbon isotope ratio of the CO2 matches that of lipid. With time, the ratio approaches that typical of starch or protein. An estimation has been made of the contribution of lipid and carbohydrate to the total respiration at each juncture. In connection with additional observations, it was deduced that the basal, or initial, respiration represents lipid metabolism —- possibly the alpha-oxidation of long chain fatty acids -— while the developed repiration represents conventional tricarboxylic acid cycle oxidation of the products of carbohydrate glycolysis. The true isotopic composition of the respiratory CO2 may be obscured by fractionation attending the refixation of CO2 during respiration, and by CO2 arising from dissolved CO2 and bicarbonate preexisting in the tuber. Means are described for coping with both pitfalls

    PROGRESS IN ESTIMATING THE MARGINAL COSTS OF GREENHOUSE GAS EMISSIONS

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    The unjust distributional consequences of climate change, and its potentially negative aggregate effect on economic growth and welfare are two reasons to be concerned about climate change. Our knowledge of the impact of climate change is incomplete. Monetary valuation is difficult and controversial. The effect of other developments on the impacts of climate change is largely speculative. Nonetheless, it can be shown that poorer countries and people are more vulnerable than are richer countries and people. A modest global warming is likely to have a net negative effect on poor economics in hot climates, but may have a positive effect on rich economies in temperate climates. If one counts dollars, the world aggregate impact may be positive. If one counts people, the world aggregate effect is probably negative. For more substantial warming, negative effects become more negative, and positive effects turn negative. The marginal costs of carbon dioxide emissions are uncertain and sensitive to assumptions that partially reflect ethical and methodological positions, but are unlikely to exceed 50pertonneofcarbon.Themarginalcostsofmethaneemissionarelikelytobelessthan50 per tonne of carbon. The marginal costs of methane emission are likely to be less than 250/tCH4; the marginal costs of nitrous oxide emissions are probably lower than $7000/tN2O. Global warming potentials, the official manner to trade-off the various greenhouse gases, do not reflect, conceptually or numerically, the real tradeoffs in either a cost-benefit or a cost-effectiveness framework.Impacts of climate change, economic valuation, equity, marginal costs

    Zeroing in on more photons and gluons

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    We discuss radiation zeros that are found in gauge tree amplitudes for processes involving multi-photon emission. Previous results are clarified by examples and by further elaboration. The conditions under which such amplitude zeros occur are identical in form to those for the single-photon zeros, and all radiated photons must travel parallel to each other. Any other neutral particle likewise must be massless (e.g. gluon) and travel in that common direction. The relevance to questions like gluon jet identification and computational checks is considered. We use examples to show how certain multi-photon amplitudes evade the zeros, and to demonstrate the connection to a more general result, the decoupling of an external electromagnetic plane wave in the ``null zone". Brief comments are made about zeros associated with other gauge-boson emission.Comment: 26 page

    Breast cancer worry in higher-risk women offered preventive therapy: a UK multicentre prospective study

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    PURPOSE: Women's worry about developing breast cancer may influence their decision to use preventive therapy. However, the direction of this relationship has been questioned. We prospectively investigated the relationship between breast cancer worry and uptake of preventive therapy. The socio-demographic and clinical factors associated with high breast cancer worry were also investigated. METHODS: Women at increased risk of developing breast cancer were recruited from clinics across England (n = 408). Participants completed a survey on their breast cancer worry, socio-demographic and clinical factors. Uptake of tamoxifen was recorded at 3 months (n = 258 women, 63.2%). Both primary and sensitivity analyses were conducted using different classifications of low, medium and high worry. RESULTS: 39.5% of respondents reported medium breast cancer worry at baseline and 21.2% reported high worry. Ethnic minority women were more likely to report high worry than white women (OR = 3.02, 95%CI 1.02, 8.91, p = 0.046). Women educated below degree level were more likely to report high worry than those with higher education (OR = 2.29, 95%CI 1.28, 4.09, p = 0.005). No statistically significant association was observed between worry and uptake. In the primary analysis, fewer respondents with medium worry at baseline initiated tamoxifen (low worry = 15.5%, medium = 13.5%, high = 15.7%). In the sensitivity analysis, participants with medium worry reported the highest uptake of tamoxifen (19.7%). CONCLUSIONS: No association was observed between worry and uptake, although the relationship was affected by the categorisation of worry. Standardised reporting of the classification of worry is warranted to allow transparent comparisons across cohorts

    Randomized Algorithms Considered Harmful

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    Recent advances in distributed communication and omniscient algorithms cooperate in order to achieve operating systems. Given the current status of relational information, cyberinformaticians dubiously desire the visualization of randomized algorithms, which embodies the confirmed principles of loss-less software engineering. We argue that the lookaside buffer can be made pseudorandom, “smart”, and client-server

    Non-Emergency Medical Transportation Needs of Middle-Aged and Older Adults: A Rural-Urban Comparison in Delaware, USA.

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    Background: Older adults in rural areas have unique transportation barriers to accessing medical care, which include a lack of mass transit options and considerable distances to health-related services. This study contrasts non-emergency medical transportation (NEMT) service utilization patterns and associated costs for Medicaid middle-aged and older adults in rural versus urban areas. Methods: Data were analyzed from 39,194 NEMT users of LogistiCare-brokered services in Delaware residing in rural (68.3%) and urban (30.9%) areas. Multivariable logistic analyses compared trip characteristics by rurality designation. Results: Rural (37.2%) and urban (41.2%) participants used services more frequently for dialysis than for any other medical concern. Older age and personal accompaniment were more common and wheel chair use was less common for rural trips. The mean cost per trip was greater for rural users (difference of $2910 per trip), which was attributed to the greater distance per trip in rural areas. Conclusions: Among a sample who were eligible for subsidized NEMT and who utilized this service, rural trips tended to be longer and, therefore, higher in cost. Over 50% of trips were made for dialysis highlighting the need to address prevention and, potentially, health service improvements for rural dialysis patients

    Adherence to treatment with artemether-lumefantrine or amodiaquine-artesunate for uncomplicated malaria in children in Sierra Leone: a randomized trial.

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    BACKGROUND: Prompt, effective treatment of confirmed malaria cases with artemisinin-based combination therapy (ACT) is a cornerstone of malaria control. Maximizing adherence to ACT medicines is key to ensuring treatment effectiveness. METHODS: This open-label, randomized trial evaluated caregiver adherence to co-formulated artemether-lumefantrine (AL) and fixed-dose amodiaquine-artesunate (AQAS) in Sierra Leone. Children aged 6-59 months diagnosed with malaria were recruited from two public clinics, randomized to receive AL or AQAS, and visited at home the day after completing treatment. Analyses were stratified by site, due to differences in participant characteristics and outcomes. RESULTS: Of the 784 randomized children, 680 (85.6%) were included in the final per-protocol analysis (340 AL, 340 AQAS). Definite adherence (self-reported adherence plus empty package) was higher for AL than AQAS at both sites (Site 1: 79.4% AL vs 63.4% AQAS, odds ratio [OR] 2.16, compared to probable adherence plus probable or definite non-adherence, 95% confidence interval [CI] 1.34-3.49; p = 0.001; Site 2: 52.1% AL vs 37.5% AQAS, OR 1.53, 95% CI 1.00-2.33, p = 0.049). However, self-reported adherence (ignoring drug package inspection) was higher for both regimens at both sites and there was no strong evidence of variation by treatment (Site 1: 96.6% AL vs 95.9% AQAS, OR 1.19, 95% CI 0.39-3.63, p = 0.753; Site 2: 91.5% AL vs 96.4% AQAS, OR 0.40, 95% CI 0.15-1.07, p = 0.067). In Site 2, correct treatment (correct dose + timing + duration) was lower for AL than AQAS (75.8% vs 88.1%, OR 0.42, 95% CI 0.23-0.76, p = 0.004). In both sites, more caregivers in the AQAS arm reported adverse events (Site 1: 3.4% AL vs 15.7% AQAS, p < 0.001; Site 2: 15.2% AL vs 24.4% AQAS, p = 0.039). CONCLUSIONS: Self-reported adherence was high for both AL and AQAS, but varied by site. These results suggest that each regimen has potential disadvantages that might affect adherence; AL was less likely to be taken correctly at one site, but was better tolerated than AQAS at both sites. Measuring adherence to anti-malarials remains challenging, but important. Future research should focus on comparative studies of new drug regimens, and improving the methodology of measuring adherence. TRIAL REGISTRATION: Clinicaltrials.gov, NCT01967472. Retrospectively registered 18 October 2013, https://clinicaltrials.gov/ct2/show/NCT01967472

    Advocating for and Providing Quality Adaptive Physical Education

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    Ideally, as put across by the Disability &amp; Human Rights guide, the Convention on the Rights of Persons with Disabilities (CRPD) does not give a detailed description of disability but rather gives a wide range of features that intend describe disability. The truth is, despite being incapacitated in a certain way, people living with disabilities should be given the same opportunities as those without. Our separate literature analysis discovered that different efforts had been put in place to present equal opportunities for people living with disabilities. One of these efforts is adaptive physical education. As its name suggests, adaptive physical education is a physical education that has been adapted to create equal opportunities for persons with disabilities as it is for people without disabilities. To this effect, this paper and its entirety will focus on presenting the different themes observed from the different pieces of literature separately
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