1,147 research outputs found
An unusual case of spontaneous bladder perforation with associated autodialysis of the ensuing urinary ascites
Spontaneous rupture of the urinary bladder is a rare occurrence, and when encountered it is a diagnostic challenge. We present an unusual case of urinary bladder rupture in a patient with severe cerebral palsy who initially presented with localized abdominal pain and during admission developed generalized peritonitis caused by bladder rupture. In this case, the patient had none of risk factors associated with urinary bladder
Time-Fractional KdV Equation for the plasma in auroral zone using Variational Methods
The reductive perturbation method has been employed to derive the Korteweg-de
Vries (KdV) equation for small but finite amplitude electrostatic waves. The
Lagrangian of the time fractional KdV equation is used in similar form to the
Lagrangian of the regular KdV equation. The variation of the functional of this
Lagrangian leads to the Euler-Lagrange equation that leads to the time
fractional KdV equation. The Riemann-Liouvulle definition of the fractional
derivative is used to describe the time fractional operator in the fractional
KdV equation. The variational-iteration method given by He is used to solve the
derived time fractional KdV equation. The calculations of the solution with
initial condition A0*sech(cx)^2 are carried out. Numerical studies have been
made using plasma parameters close to those values corresponding to the dayside
auroral zone. The effects of the time fractional parameter on the electrostatic
solitary structures are presented.Comment: 1 tex file + 5 eps figure
The relationship between regional variations in blood flow and histology in a transplanted rat fibrosarcoma
The regional distribution of blood flow to the LBDS1 fibrosarcoma, transplanted into the subcutaneous site in rats, was investigated using the readily diffusible compound 14C-iodo-antipyrine (14C-IAP). Quantitative autoradiography was used to establish absolute values of specific blood flow F for 100 X 100 X 20 microns adjacent tissue volumes of the unperturbed tumour. Mean blood flow to whole tumours was found to decrease with increase in tumour size. This relationship was abolished if blood flow was only measured in sections cut from the periphery of the tumours. Detailed analysis of a sub-group of tumours showed that blood flow to individual tumours was heterogeneous. The range of blood flow was large, indicating that mean blood flow to a whole tumour is a poor reflection of the blood perfusion pattern of that tumour. Necrotic tumour regions were usually very poorly perfused. With the exception of the smallest tumours studied, blood flow was lower in the centre of tumours than in the periphery. Necrosis also tended to develop centrally. However, the peripheral to central gradient of blood flow was apparent even when densely cellular, viable tumour regions and necrotic regions were analysed separately. The decrease in blood flow with tumour size was also apparent in densely cellular, viable tumour regions when analysed separately. Qualitative comparison of tumour histology and regional blood flow showed that there were areas of very low blood flow associated with viable tumour regions. Less common were areas of rather high blood flow associated with necrotic tumour regions. A complicated relationship exists between tumour histology and blood flow. The quantitative autoradiography technique is suitable for investigating the most poorly perfused and the most well perfused viable fractions of animal tumours which may limit the efficacy of different types of therapy
The tension between fire risk and carbon storage: evaluating U.S. carbon and fire management strategies through ecosystem models
Fire risk and carbon storage are related environmental issues because fire reduction results in carbon storage through the buildup of woody vegetation, and stored carbon is a fuel for fires. The sustainability of the U.S. carbon sink and the extent of fire activity in the next 100 yr depend in part on the type and effectiveness of fire reduction employed. Previous studies have bracketed the range of dynamics from continued fire reduction to the complete failure of fire reduction activities. To improve these estimates, it is necessary to explicitly account for fire reduction in terrestrial models. A new fire reduction submodel that estimates the spatiotemporal pattern of reduction across the United States was developed using gridded data on biomass, climate, land-use, population, and economic factors. To the authors’ knowledge, it is the first large-scale, gridded fire model that explicitly accounts for fire reduction. The model was calibrated to 1° × 1° burned area statistics [Global Burnt Area 2000 Project (GBA-2000)] and compared favorably to three important diagnostics. The model was then implemented in a spatially explicit ecosystem model and used to analyze 1620 scenarios of future fire risk and fire reduction strategies. Under scenarios of climate change and urbanization, burned area and carbon emissions both increased in scenarios where fire reduction efforts were not adjusted to match new patterns of fire risk. Fuel reducing management strategies reduced burned area and fire risk, but also limited carbon storage. These results suggest that to promote carbon storage and minimize fire risk in the future, fire reduction efforts will need to be increased and spatially adjusted and will need to employ a mixture of fuel-reducing and non-fuel-reducing strategies
DIRECT ESTIMATION OF ABOVEGROUND FOREST PRODUCTIVITY THROUGH HYPERSPECTRAL REMOTE SENSING OF CANOPY NITROGEN
The concentration of nitrogen in foliage has been related to rates of net photosynthesis across a wide range of plant species and functional groups and thus represents a simple and biologically meaningful link between terrestrial cycles of carbon and nitrogen. Although foliar N is used by ecosystem models to predict rates of leaf‐level photosynthesis, it has rarely been examined as a direct scalar to stand‐level carbon gain. Establishment of such relationships would greatly simplify the nature of forest C and N linkages, enhancing our ability to derive estimates of forest productivity at landscape to regional scales. Here, we report on a highly predictive relationship between whole‐canopy nitrogen concentration and aboveground forest productivity in diverse forested stands of varying age and species composition across the 360 000‐ha White Mountain National Forest, New Hampshire, USA. We also demonstrate that hyperspectral remote sensing can be used to estimate foliar N concentration, and hence forest production across a large number of contiguous images. Together these data suggest that canopy‐level N concentration is an important correlate of productivity in these forested systems, and that imaging spectrometry of canopy N can provide direct estimates of forest productivity across large landscapes
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Impression management and achievement motivation: investigating substantive links
In the present research we investigate impression management (IM) as a substantive personality variable by linking it to differentiated achievement motivation constructs, namely achievement motives (workmastery, competitiveness, fear of failure) and achievement goals (mastery-approach, mastery-avoidance, performance-approach, performance-avoidance). Study 1 revealed that IM was a positive predictor of workmastery and a negative predictor of competitiveness (with and without self-deceptive enhancement (SDE) controlled). Studies 2a and 2b revealed that IM was a positive predictor of mastery-approach goals and mastery-avoidance goals (without and, in Study 2b, with SDE controlled). These findings highlight the value of conceptualizing and utilizing IM as a personality variable in its own right, and shed light on the nature of the achievement motive and achievement goal constructs
Cardiovascular Risk Reduction is Important for Improving Patient and Graft Survival After Ligation and Bypass Surgery for Popliteal Artery Aneurysm
OBJECTIVES: To report outcomes following ligation and bypass (LGB) surgery for popliteal artery aneurysm (PAA) and study factors influencing patient and graft survival.
MATERIALS AND METHODS: A retrospective review of patients undergoing LGB surgery for PAA between September 1999 and August 2012 at a tertiary referral vascular unit was performed. Primary graft patency (PGP), primary-assisted graft patency (PAGP), and secondary graft patency (SGP) rates were calculated using survival analyses. Patient, graft aneurysm-free survival (GAFS), aneurysm reperfusion-free survival (ARFS), and amputation-free survival (AFS) rates were also calculated. Log-rank testing and Cox proportional hazards modeling were used to perform univariate and multivariate analysis of influencing factors, respectively.
RESULTS: Eighty-four LGB repairs in 69 patients (mean age 71.3 years, 68 males) were available for study. The 5-year PGP, PAGP, SGP, and patient survival rates were 58.1%, 84.4%, 85.2%, and 81.1%, respectively. On multivariate analysis, the principal determinants of PGP were urgency of operation ( P = .009) and smoking status ( P = .019). The principal determinants of PAGP were hyperlipidemia status ( P = .048) and of SGP were hyperlipidemia ( P = .042) and cerebrovascular disease (CVD) status ( P = .045). The principal determinants of patient survival were previous myocardial infarction ( P = .004) and CVD ( P = .001). The 5-year GAFS, ARFS, and AFS rates were 87.9%, 91.6%, and 96.1%, respectively.
CONCLUSION: This study has shown that traditional cardiovascular risk factors, such as a smoking and ischemic heart disease, are the most important predictors of early graft failure and patient death following LGB surgery for PAA
Families' social backgrounds matter : socio-economic factors, home learning and young children's language, literacy and social outcomes
Parental support with children's learning is considered to be one pathway through which socio-economic factors influence child competencies. Utilising a national longitudinal sample from the Millennium Cohort Study, this study examined the relationship between home learning and parents' socio-economic status and their impact on young children's language/literacy and socio-emotional competence. The findings consistently showed that, irrespective of socio-economic status, parents engaged with various learning activities (except reading) roughly equally. The socio-economic factors examined in this study, i.e., family income and maternal educational qualifications, were found to have a stronger effect on children's language/literacy than on social-emotional competence. Socio-economic disadvantage, lack of maternal educational qualifications in particular, remained powerful in influencing competencies in children aged three and at the start of primary school. For children in the first decade of this century in England, these findings have equity implications, especially as the socio-economic gap in our society widens
Acute mesenteric ischemia and duodenal ulcer perforation: a unique double pathology
Background: Acute mesenteric ischaemia and duodenal perforation are surgical emergencies with serious
consequences. Patients presenting with acute mesenteric ischaemia alone face a high mortality rate as high as 60%
whereas those presenting with peptic ulcer perforation the mortality rates range from 6-14%. There are very few
reported cases of patients presenting with this dual pathology.
Case presentation: We report a unique case of a 53 year old Italian lady who presented with acute mesenteric
ischaemia and duodenal perforation. This is the first report of massive bowel ischaemia and duodenal perforation
with no apparent underlying common pathophysiology leading to this presentation.
Conclusion: Early management in the intensive care unit and appropriate surgical intervention maximised the
patient’s chances of survival despite the poor prognosis associated with her dual pathology. The rare pathology of
the patient described can be explained by two possible hypotheses: peptic ulcer disease causing duodenal
ulceration, which precipitated ischaemic infarction of the small bowel. The second hypothesis is the patient
developed a stress related ulcer following ischaemic bowel infarction secondary to arterial thrombosis
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