1,038 research outputs found

    Predicting macrobending loss for large-mode area photonic crystal fibers

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    We report on an easy-to-evaluate expression for the prediction of the bend-loss for a large mode area photonic crystal fiber (PCF) with a triangular air-hole lattice. The expression is based on a recently proposed formulation of the V-parameter for a PCF and contains no free parameters. The validity of the expression is verified experimentally for varying fiber parameters as well as bend radius. The typical deviation between the position of the measured and the predicted bend loss edge is within measurement uncertainty.Comment: Accepted for Optics Expres

    Impacts of the amount of hybrid cattail (Typha x glauca) litter on abiotic and biotic conditions in prairie pothole wetlands

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    Hybrid cattail (Typha x glauca) is an invasive emergent macrophyte that spreads quickly and forms monodominant stands in wetlands, and alters their abiotic and biotic conditions. I examined the role that cattail litter has on abiotic and biotic conditions. Specifically, I studied experimentally the effects of the amount of litter in a mesocosm complex and a prairie pothole wetland. At both sites, I established three litter treatments (high, control, and low litter amounts) and examined how the amount of litter effects litter decomposition, cattail shoot number and height, temperature (at the sediment surface, as well as 10cm above and 10cm below), soil redox potential, dissolved oxygen, and percent oxygen saturation. I hypothesized that when litter increased at a site, there would be a corresponding decrease in soil and water temperature, redox potential, dissolved oxygen, and percent oxygen saturation and consequently in the rate of litter decomposition. I also hypothesized that the number of cattail shoots and cattail shoot heights would decrease with increasing litter. There was no significant difference among the litter treatments in litter decomposition rates at either location. Temperatures varied across treatments, with a greater mean maximum and minimum in the low treatment at all three depths (+10cm, 0cm, -10cm) at the mesocosm complex, but not at Anderson Lake. Redox potential, dissolved oxygen, and percent oxygen saturation in the low treatments at the mesocosm complex were significantly higher than in either the high or control treatments, but again not at Anderson Lake. The number of cattail shoots was significantly higher in the low treatments than in the high and control treatments in the mesocosm complex and between the low and high treatments at Anderson Lake

    Wind environment evaluation on major town of Malaysia

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    This study focus on wind flow or wind environment of residential areas in Peninsular Malaysia, Sabah and Sarawak. Natural wind flow is one of the most effective methods to help achieve the energy saving in large cities especially under the tropical climate like Malaysia. The weather in Malaysia is characterized by four monsoon regimes, namely, the southwest monsoon, northeast monsoon and two shorter periods of inter-monsoon seasons. For this study, the data of wind velocity in twentytwo (22) weather station in Malaysia obtained from Meteorological Department and considered in wind environment evaluations. Then that data of wind velocities will convert to 1.5 in height at all measuring points were calculated by using the law. The result compared by Table 2.2 in previous researches (Kubota and Miura et al., 2002). From the study, it was found out, in Malaysia there are only two type of wind. First type is weak wind means that area are discomfort thermal and the second type is comfort range to strong wind means that area are comfort thermal. The minimum value of mean wind speed from 2005 to 2009 is O.mis in mean temperature is over 2C at Sitiawan. For the maximum value of mean wind speed is I .7m/s in average value of mean temperature is 276C at Mersing. Base on results, it can be concluded that when considering wind flow at a residential area, terrace housing is not a suitable option for towns located on the south of the Peninsular. It was prefer for high-rise building because it was considered this location of towns was weak wind condition. On the other hand, the major towns exclude the south of the Peninsular including Sabah and Sarawak, they was under the comfort thermal. So, terrace housing or high-rise building is suitable option

    Competing mortality in patients diagnosed with bladder cancer: evidence of undertreatment in the elderly and female patients

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    Background: Bladder cancer (BC) predominantly affects the elderly and is often the cause of death among patients with muscleinvasive disease. Clinicians lack quantitative estimates of competing mortality risks when considering treatments for BC. Our aim was to determine the bladder cancer-specific mortality (CSM) rate and other-cause mortality (OCM) rate for patients with newly diagnosed BC. Methods: Patients (n ¼ 3281) identified from a population-based cancer registry diagnosed between 1994 and 2009. Median follow-up was 48.15 months (IQ range 18.1–98.7). Competing risk analysis was performed within patient groups and outcomes compared using Gray’s test. Results: At 5 years after diagnosis, 1246 (40%) patients were dead: 617 (19%) from BC and 629 (19%) from other causes. The 5-year BC mortality rate varied between 1 and 59%, and OCM rate between 6 and 90%, depending primarily on the tumour type and patient age. Cancer-specific mortality was highest in the oldest patient groups. Few elderly patients received radical treatment for invasive cancer (52% vs 12% for patients o60 vs 480 years, respectively). Female patients with high-risk non-muscle-invasive BC had worse CSM than equivalent males (Gray’s Po0.01). Conclusion: Bladder CSM is highest among the elderly. Female patients with high-risk tumours are more likely to die of their disease compared with male patients. Clinicians should consider offering more aggressive treatment interventions among older patients

    Long-lived magnetism from solidification-driven convection on the pallasite parent body.

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    Palaeomagnetic measurements of meteorites suggest that, shortly after the birth of the Solar System, the molten metallic cores of many small planetary bodies convected vigorously and were capable of generating magnetic fields. Convection on these bodies is currently thought to have been thermally driven, implying that magnetic activity would have been short-lived. Here we report a time-series palaeomagnetic record derived from nanomagnetic imaging of the Imilac and Esquel pallasite meteorites, a group of meteorites consisting of centimetre-sized metallic and silicate phases. We find a history of long-lived magnetic activity on the pallasite parent body, capturing the decay and eventual shutdown of the magnetic field as core solidification completed. We demonstrate that magnetic activity driven by progressive solidification of an inner core is consistent with our measured magnetic field characteristics and cooling rates. Solidification-driven convection was probably common among small body cores, and, in contrast to thermally driven convection, will have led to a relatively late (hundreds of millions of years after accretion), long-lasting, intense and widespread epoch of magnetic activity among these bodies in the early Solar System.The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement No. 320750, the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 312284, the Natural Environment Research Council, Fundación ARAID and the Spanish MINECO MAT2011-23791.This is the accepted manuscript. The final version is available from Nature at http://www.nature.com/nature/journal/v517/n7535/full/nature14114.html

    Long-term outcome among men with conservatively treated localised prostate cancer.

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    Optimal management of clinically localised prostate cancer presents unique challenges, because of its highly variable and often indolent natural history. There is an urgent need to predict more accurately its natural history, in order to avoid unnecessary treatment. Medical records of men diagnosed with clinically localised prostate cancer, in the UK, between 1990 and 1996 were reviewed to identify those who were conservatively treated, under age 76 years at the time of pathological diagnosis and had a baseline prostate-specific antigen (PSA) measurement. Diagnostic biopsy specimens were centrally reviewed to assign primary and secondary Gleason grades. The primary end point was death from prostate cancer and multivariate models were constructed to determine its best predictors. A total of 2333 eligible patients were identified. The most important prognostic factors were Gleason score and baseline PSA level. These factors were largely independent and together, contributed substantially more predictive power than either one alone. Clinical stage and extent of disease determined, either from needle biopsy or transurethral resection of the prostate (TURP) chips, provided some additional prognostic information. In conclusion, a model using Gleason score and PSA level identified three subgroups comprising 17, 50, and 33% of the cohort with a 10-year prostate cancer specific mortality of 30%, respectively. This classification is a substantial improvement on previous ones using only Gleason score, but better markers are needed to predict survival more accurately in the intermediate group of patients
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