958 resultados para Life-times
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Emergency Departments (EDs) and Emergency Rooms (ERs) are designed to manage trauma, respond to disasters, and serve as the initial care for those with serious illnesses. However, because of many factors, the ED has become the doorway to the hospital and a “catch-all net” for patients including those with non-urgent needs. This increase in the population in the ED has lead to an increase in wait times for patients. It has been well documented that there has been a constant and consistent rise in the number of patients that frequent the ED (National Center for Health Statistics, 2002); the wait time for patients in the ED has increased (Pitts, Niska, Xu, & Burt, 2008); and the cost of the treatment in the ER has risen (Everett Clinic, 2008). Because the ED was designed to treat patients who need quick diagnoses and may be in potential life-threatening circumstances, management of time can be the ultimate enemy. If a system was implemented to decrease wait times in the ED, decrease the use of ED resources, and decrease costs endured by patients seeking care, better outcomes for patients and patient satisfaction could be achieved. The goal of this research was to explore potential changes and/or alternatives to relieve the burden endured by the ED. In order to explore these options, data was collected by conducting one-on-one interviews with seven physicians closely tied to a Level 1 ED (Emergency Room physicians, Trauma Surgeons and Primary Care physicians). A qualitative analysis was performed on the responses of one-on-one interviews with the aforementioned physicians. The interviews were standardized, open-ended questions that probe what makes an effective ED, possible solutions to improving patient care in the ED, potential remedies for the mounting problems that plague the ED, and the feasibility of bringing Primary Care Physicians to the ED to decrease the wait times experienced by the patient. From the responses, it is clear that there needs to be more research in this area, several areas need to be addressed, and a variety of solutions could be implemented. The most viable option seems to be making the ED its own entity (similar to the clinic or hospital) that includes urgent clinics as a part of the system, in which triage and better staffing would be the most integral part of its success.^
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Statistical methods are developed which assess survival data for two attributes; (1) prolongation of life, (2) quality of life. Health state transition probabilities correspond to prolongation of life and are modeled as a discrete-time semi-Markov process. Imbedded within the sojourn time of a particular health state are the quality of life transitions. They reflect events which differentiate perceptions of pain and suffering over a fixed time period. Quality of life transition probabilities are derived from the assumptions of a simple Markov process. These probabilities depend on the health state currently occupied and the next health state to which a transition is made. Utilizing the two forms of attributes the model has the capability to estimate the distribution of expected quality adjusted life years (in addition to the distribution of expected survival times). The expected quality of life can also be estimated within the health state sojourn time making more flexible the assessment of utility preferences. The methods are demonstrated on a subset of follow-up data from the Beta Blocker Heart Attack Trial (BHAT). This model contains the structure necessary to make inferences when assessing a general survival problem with a two dimensional outcome. ^
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Seasonal variation in menarche, menstrual cycle length and menopause was investigated using Tremin Trust data. Too, self-reported hot flash data for women with natural and surgically-induced menopause were analyzed for rhythms.^ Menarche data from approximately 600 U.S. women born between 1940 and 1970 revealed a 6-month rhythm (first acrophase in January, double amplitude of 58%M). A notable shift from a December-January peak in menarche for those born in the 1940s and 1950s to an August-September peak for those born in the 1960s was observed. Groups of girls 8-14 and 15-17 yr old at menarche exhibited a seasonal difference in the pattern of menarche occurrence of about 6 months in relation to each other. Girls experiencing menarche during August-October were statistically significantly younger than those experiencing it at other times. Season of birth was not associated with season of menarche.^ The lengths of approximately 150,000 menstrual intervals of U.S. women were analyzed for seasonality. Menstrual intervals possibly disturbed by natural (e.g., childbirth) or other events (e.g., surgery, medication) were excluded. No 6- or 12-month rhythmicities were found for specific interval lengths (14-24, 25-31 and 32-56 days) or ages in relation to menstrual interval (9-11, 12-13, 15-19, 20-24, 25-39, 40-44 and 44 yr old and older).^ Hot flash data of 14 women experiencing natural menopause (NM) and 11 experiencing surgically-induced menopause (SIM) did not differ in frequency of hot flashes. Hot flashes in NM women exhibited 12- and 8-hr, but not 24-hr rhythmicities. Hot flashes in SIM women exhibited 24- and 12-hr, but not 8-hr, rhythmicities. Regardless of type of menopause, women with a peak frequency in hot flashes during the morning (0400 through 0950) were distinguishable from those with such in the evening (1600 through 2159).^ Data from approximately 200 U.S. women revealed a 6-month rhythm in menopause with first peak in May. No significant 12-month variation in menopause was detected by Cosinor analysis. Season of birth and age at menopause were not associated with season of menopause. Age at menopause declined significantly over the years for women born between 1907 and 1926, inclusive. ^
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The effects of fungal endophytes Beauveria bassiana isolates ICIPE 279, G1LU3, S4SU1 and Hypocrea lixii isolate F3ST1 on the life-history of Phaedrotoma scabriventris and Diglyphus isaea, parasitoids of the pea leafminer Liriomyza huidobrensis, were studied in the laboratory. Parasitoids were allowed to parasitize 2nd-3rd L. huidobrensis larvae reared on endophytically-inoculated Vicia faba. In the control, parasitoids were reared on non-inoculated host plants. Parasitism, pupation, adult emergence and survival were recorded. No significant difference was observed between the control and the endophyte-inoculated plants in terms of parasitism rates of P. scabriventris (p = 0.68) and D. isaea (p = 0.45) and adult' survival times (p = 0.06). The survival period of the F1 progeny of P. scabriventris was reduced (p < 0.0001) in B. bassiana S4SU1 to 28 days as compared to more than 40 days for B. bassiana G1LU3, ICIPE 279 and H. lixii F3ST1. However, no significant difference (p = 0.54) was observed in the survival times of the F1 progeny of D. isaea. This study has therefore demonstrated the beneficial effects of both endophytes and parasitoids in L. huidobrensis population suppression.
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Concentrator photovoltaic is an emergent technology that may be a good economical and efficient alternative for the generation of electricity at a competitive cost. However, the reliability of these new solar cells and systems is still an open issue due to the high-irradiation level they are subjected to as well as the electrical and thermal stresses that they are expected to endure. To evaluate the reliability in a short period of time, accelerated aging tests are essential. Thermal aging tests for concentrator photovoltaic solar cells and systems under illumination are not available because no technical solution to the problem of reaching the working concentration inside a climatic chamber has been available. This work presents an automatic instrumentation system that overcomes the aforementioned limitation. Working conditions have been simulated by forward biasing the solar cells to the current they would handle at the working concentration (in this case, 700 and 1050 times the irradiance at one standard sun). The instrumentation system has been deployed for more than 10 000 h in a thermal aging test for III-V concentrator solar cells, in which the generated power evolution at different temperatures has been monitored. As a result of this test, the acceleration factor has been calculated, thus allowing for the degradation evolution at any temperature in addition to normal working conditions to be obtained.
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Purpose Concentrating Solar Power (CSP) plants based on parabolic troughs utilize auxiliary fuels (usually natural gas) to facilitate start-up operations, avoid freezing of HTF and increase power output. This practice has a significant effect on the environmental performance of the technology. The aim of this paper is to quantify the sustainability of CSP and to analyse how this is affected by hybridisation with different natural gas (NG) inputs. Methods A complete Life Cycle (LC) inventory was gathered for a commercial wet-cooled 50 MWe CSP plant based on parabolic troughs. A sensitivity analysis was conducted to evaluate the environmental performance of the plant operating with different NG inputs (between 0 and 35% of gross electricity generation). ReCiPe Europe (H) was used as LCA methodology. CML 2 baseline 2000 World and ReCiPe Europe E were used for comparative purposes. Cumulative Energy Demands (CED) and Energy Payback Times (EPT) were also determined for each scenario. Results and discussion Operation of CSP using solar energy only produced the following environmental profile: climate change 26.6 kg CO2 eq/KWh, human toxicity 13.1 kg 1,4-DB eq/KWh, marine ecotoxicity 276 g 1,4-DB eq/KWh, natural land transformation 0.005 m2/KWh, eutrophication 10.1 g P eq/KWh, acidification 166 g SO2 eq/KWh. Most of these impacts are associated with extraction of raw materials and manufacturing of plant components. The utilization NG transformed the environmental profile of the technology, placing increasing weight on impacts related to its operation and maintenance. Significantly higher impacts were observed on categories like climate change (311 kg CO2 eq/MWh when using 35 % NG), natural land transformation, terrestrial acidification and fossil depletion. Despite its fossil nature, the use of NG had a beneficial effect on other impact categories (human and marine toxicity, freshwater eutrophication and natural land transformation) due to the higher electricity output achieved. The overall environmental performance of CSP significantly deteriorated with the use of NG (single score 3.52 pt in solar only operation compared to 36.1 pt when using 35 % NG). Other sustainability parameters like EPT and CED also increased substantially as a result of higher NG inputs. Quasilinear second-degree polynomial relationships were calculated between various environmental performance parameters and NG contributions. Conclusions Energy input from auxiliary NG determines the environmental profile of the CSP plant. Aggregated analysis shows a deleterious effect on the overall environmental performance of the technology as a result of NG utilization. This is due primarily to higher impacts on environmental categories like climate change, natural land transformation, fossil fuel depletion and terrestrial acidification. NG may be used in a more sustainable and cost-effective manner in combined cycle power plants, which achieve higher energy conversion efficiencies.
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The life-history strategies of organisms are sculpted over evolutionary time by the relative prospects of present and future reproductive success. As a consequence, animals of many species show flexible behavioral responses to environmental and social change. Here we show that disruption of the habitat of a colony of African cichlid fish, Haplochromis burtoni (Günther) caused males to switch social status more frequently than animals kept in a stable environment. H. burtoni males can be either reproductively active, guarding a territory, or reproductively inactive (nonterritorial). Although on average 25–50% of the males are territorial in both the stable and unstable environments, during the 20-week study, nearly two-thirds of the animals became territorial for at least 1 week. Moreover, many fish changed social status several times. Surprisingly, the induced changes in social status caused changes in somatic growth. Nonterritorial males and animals ascending in social rank showed an increased growth rate whereas territorial males and animals descending in social rank slowed their growth rate or even shrank. Similar behavioral and physiological changes are caused by social change in animals kept in stable environmental conditions, although at a lower rate. This suggests that differential growth, in interaction with environmental conditions, is a central mechanism underlying the changes in social status. Such reversible phenotypic plasticity in a crucial life-history trait may have evolved to enable animals to shift resources from reproduction to growth or vice versa, depending on present and future reproductive prospects.
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A recent study of the divergence times of the major groups of organisms as gauged by amino acid sequence comparison has been expanded and the data have been reanalyzed with a distance measure that corrects for both constraints on amino acid interchange and variation in substitution rate at different sites. Beyond that, the availability of complete genome sequences for several eubacteria and an archaebacterium has had a great impact on the interpretation of certain aspects of the data. Thus, the majority of the archaebacterial sequences are not consistent with currently accepted views of the Tree of Life which cluster the archaebacteria with eukaryotes. Instead, they are either outliers or mixed in with eubacterial orthologs. The simplest resolution of the problem is to postulate that many of these sequences were carried into eukaryotes by early eubacterial endosymbionts about 2 billion years ago, only very shortly after or even coincident with the divergence of eukaryotes and archaebacteria. The strong resemblances of these same enzymes among the major eubacterial groups suggest that the cyanobacteria and Gram-positive and Gram-negative eubacteria also diverged at about this same time, whereas the much greater differences between archaebacterial and eubacterial sequences indicate these two groups may have diverged between 3 and 4 billion years ago.
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The location and density of biologically useful energy sources on Mars will limit the biomass, spatial distribution, and organism size of any biota. Subsurface Martian organisms could be supplied with a large energy flux from the oxidation of photochemically produced atmospheric H2 and CO diffusing into the regolith. However, surface abundance measurements of these gases demonstrate that no more than a few percent of this available flux is actually being consumed, suggesting that biological activity driven by atmospheric H2 and CO is limited in the top few hundred meters of the subsurface. This is significant because the available but unused energy is extremely large: for organisms at 30-m depth, it is 2,000 times previous estimates of hydrothermal and chemical weathering energy and far exceeds the energy derivable from other atmospheric gases. This also implies that the apparent scarcity of life on Mars is not attributable to lack of energy. Instead, the availability of liquid water may be a more important factor limiting biological activity because the photochemical energy flux can only penetrate to 100- to 1,000-m depth, where most H2O is probably frozen. Because both atmospheric and Viking lander soil data provide little evidence for biological activity, the detection of short-lived trace gases will probably be a better indicator of any extant Martian life.
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"To prove from Shakespeare's works that he has painted himself twenty times from youth till age at full length."--Introd.
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Mode of access: Internet.
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Behind the times -- His first operation -- A straggler of '15 -- The third generation -- A false start -- The curse of Eve -- Sweethearts -- A physiologist's wife -- The case of Lady Sannox -- A question of diplomacy -- A medical document -- Lot no. 249 -- The Los Amigos fiasco -- The doctors of Hoyland -- The surgeon talks.
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Publisher's catalogue precedes and follows text.
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Includes index.
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Mode of access: Internet.