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Many Causes (many + cause)
Selected AbstractsResolving the biodiversity paradoxECOLOGY LETTERS, Issue 8 2007James S. Clark Abstract The paradox of biodiversity involves three elements, (i) mathematical models predict that species must differ in specific ways in order to coexist as stable ecological communities, (ii) such differences are difficult to identify, yet (iii) there is widespread evidence of stability in natural communities. Debate has centred on two views. The first explanation involves tradeoffs along a small number of axes, including ,colonization-competition', resource competition (light, water, nitrogen for plants, including the ,successional niche'), and life history (e.g. high-light growth vs. low-light survival and few large vs. many small seeds). The second view is neutrality, which assumes that species differences do not contribute to dynamics. Clark et al. (2004) presented a third explanation, that coexistence is inherently high dimensional, but still depends on species differences. We demonstrate that neither traditional low-dimensional tradeoffs nor neutrality can resolve the biodiversity paradox, in part by showing that they do not properly interpret stochasticity in statistical and in theoretical models. Unless sample sizes are small, traditional data modelling assures that species will appear different in a few dimensions, but those differences will rarely predict coexistence when parameter estimates are plugged into theoretical models. Contrary to standard interpretations, neutral models do not imply functional equivalence, but rather subsume species differences in stochastic terms. New hierarchical modelling techniques for inference reveal high-dimensional differences among species that can be quantified with random individual and temporal effects (RITES), i.e. process-level variation that results from many causes. We show that this variation is large, and that it stands in for species differences along unobserved dimensions that do contribute to diversity. High dimensional coexistence contrasts with the classical notions of tradeoffs along a few axes, which are often not found in data, and with ,neutral models', which mask, rather than eliminate, tradeoffs in stochastic terms. This mechanism can explain coexistence of species that would not occur with simple, low-dimensional tradeoff scenarios. [source] Analysis of skin images using texture descriptor by a combined statistical and structural approachINTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 6 2007C. Umarani Abstract In this article, an attempt has been made to analyze various skin (textured) images. They are caused because of hot water, chemical, electrical, thermal, cigarette, etc. These images are analyzed using our texture representation scheme. Our approach uses a set of 92 texture primitives. They are tested for the presence of texture by a statistical design of experiments based approach [Ganesan and Bhattacharyya, Pattern Recogn 28 (1995), 99,105]. These texture primitives are concluded as the local descriptor and their distribution over the entire image is the global representation called texture primitive spectrum. The set of texture primitives and the texture primitive spectrums are successful for a number of Bench mark images (Brodatz, Texture,A photographic album for artists and designers, Reinbold, New York, 1968; Vistex, Available at http://www.white.media.mit.edu\vismod\imgery\Vision Texture, MIT Media Lab, 1995). Using the texture primitive spectrum, several texture images have been categorized as micro, macro, fine, and coarse and a trend is obtained. Similarly, a set of skin images affected by severe burn with many causes are analyzed. The severity has been quantified and concluded based on simple and weighted mean computed for the texture primitive spectrums. The extent of burn and hence the curing duration can be approximated from the results. The outcome of our experimentation with ground truth and the opinion from the experts are closely matching. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 17, 359,366, 2007 [source] Soft tissue uptake on 99mTc methylene diphosphonate bone scan imaging: Pictorial reviewJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 1 2002J Kaye SUMMARY 99mTechnetium methylene diphosphonate (MDP) bone isotope may accumulate in many extra-osseous sites due to a variety of both benign and malignant conditions. This finding on a bone scan can be crucial to the diagnosis and may not be apparent in other imaging or the clinical evaluation of the patient. We present a pictorial review sampling some of the many causes of extra-osseous 99mTc MDP accumulation. [source] Intracranial Vasculitis and Multiple Abscesses in a Pregnant WomanJOURNAL OF NEUROIMAGING, Issue 3 2001Mutlu Cihangiroglu ABSTRACT Cerebral vasculitis is an unusual disorder with many causes. Infectious causes of cerebral vasculitis are predominantly bacterial or viral in nature. Purulent bacterial vasculitis is most often a complication of severe bacterial meningitis. The patient is a 25-year-old African American female, 25 weeks pregnant, who presented to the neurology service after a consult and referral from an outside hospital. She had a 1-month history of right sixth nerve palsy. Initial workup included a negative lumber puncture and a noninfused magnetic resonance imaging (MRI). Three days later, the patient developed right-sided migraine headaches and right third nerve palsy. The angiogram revealed diffuse irregularity and narrowing of the petrous, cavernous, and supraclinoid portions of the internal carotid and right middle cerebral arteries. Shortly thereafter, an MRI examination revealed diffuse leptomeningeal enhancement and abscess and a right parietal subdural empyema. Infectious vasculitis secondary to purulent meningitis has a rapidly progressive course and presents with cranial nerve palsy with involvement of the cavernous sinus. Although the association of this disease with pregnancy has not been established, it should be recognized that the early imaging studies may be negative or discordant and follow-up imaging might be necessary. [source] Voluntary turnover among nurses working in Kuwaiti hospitalsJOURNAL OF NURSING MANAGEMENT, Issue 3 2008MUHAMMAD ALOTAIBI BSN Background, Voluntary turnover rates are high among staff nurses working in Kuwaiti hospitals. It is a major problem, costly and it is presumed to impact on the quality of nursing care delivered. Aims, The two aims of this study were to (1) find out if nurses' resignations in Kuwaiti hospitals could be ascribed to failure in the recruitment process and (2) examine the feelings of nurses who resigned. Methods, Two sets of exit interviews with 60 nurses who had resigned were conducted. Results, No evidence emerged that any false information or misleading information was provided except for the salary adjustments. The real insight lay in what might not have been said in the recruitment interviews. While feelings of discontent emerged in the interviews relating to the loss of income, the greatest source of complaint related to the failure of managers to solve the evident problems. Conclusions, High rates of voluntary turnover require more attention from administrators and policy makers because of its potential consequences in terms of the quality of nursing care delivered. Implications for nursing management, This paper identifies many causes of nurses' voluntary turnover. It also shows the need for nursing managers to explore these causes and suggests successful strategies for recruitment and retention practices and policies. [source] Bruising: When it is spontaneous and not idiopathic thrombocytopenia purpuraJOURNAL OF PAEDIATRICS AND CHILD HEALTH, Issue 4 2007Amanda L Davey Abstract: Bruising is a presentation that often causes concern. There are many causes of bruising in children, including non-accidental injury, which must be excluded. We report a case of a 22-month-old boy where all the common diagnoses were excluded. We highlight the need to be aware of transient acquired inhibitors of coagulation that can cause spontaneous bleeding. [source] Bronchial compression due to stent placement in pulmonary artery in a child with congenital heart diseasePEDIATRIC ANESTHESIA, Issue 12 2005MÓNICA NÚÑEZ MD Summary Congenital heart disease, such as transposition of the great vessels (TGV), requires surgical procedures which can lead to important complications. We report on a case of bronchial obstruction following placement of a pulmonary artery stent in a 4-year-old boy who had undergone a Rastelli procedure to correct TGV, ventricular septal defect and pulmonary stenosis. There are many complications that can arise as a consequence of intravascular stents in heart surgery, as well as many causes of bronchial compression. However we have not found any report which describes bronchial compression as a direct consequence of endovascular stent. [source] Cancer treatment-induced bone loss: A reviewASIA-PACIFIC JOURNAL OF CLINICAL ONCOLOGY, Issue 4 2006Frances BARNETT Abstract Cancer treatment-induced bone loss (CTIBL) is the phenomenon of loss of bone mass directly due to the effects of treatment for cancer. There are many causes of CTIBL. This article focuses on CTIBL in the hormone-dependent cancers (breast and prostate) and reviews the mechanisms, the extent of the problem and the management strategies. [source] A porcine model of bladder outlet obstruction incorporating radio-telemetered cystometryBJU INTERNATIONAL, Issue 1 2007Matthew B. Shaw OBJECTIVE To present a novel porcine model of bladder outlet obstruction (BOO) with a standardized bladder outlet resistance and real-time ambulatory radio-telemetered cystometry, as BOO is a common condition with many causes in both adults and children, with significant morbidity and occasional mortality, but attempts to model this condition in many animal models have the fundamental problem of standardising the degree of outlet resistance. MATERIALS AND METHODS BOO was created in nine castrated male pigs by dividing the mid-urethra; outflow was allowed through an implanted bladder drainage catheter containing a resistance valve, allowing urine to flow across the valve only when a set pressure differential was generated across the valve. An implantable radio-telemetered pressure sensor monitored the pressure within the bladder and abdominal cavity, and relayed this information to a remote computer. Four control pigs had an occluded bladder drainage catheter and pressure sensor placed, but were allowed to void normally through the native urethra. Intra-vesical pressure was monitored by telemetry, while the resistance valve was increased weekly, beginning with 2 cmH2O and ultimately reaching 10 cmH2O. The pigs were assessed using conventional cystometry under anaesthesia before death, and samples conserved in formalin for haematoxylin and eosin staining. RESULTS The pigs had radio-telemetered cystometry for a median of 26 days. All telemetry implants functioned well for the duration of the experiment, but one pig developed a urethral fistula and was excluded from the study. With BOO the bladder mass index (bladder mass/body mass × 10 000) increased from 9.7 to 20 (P = 0.004), with a significant degree of hypertrophy of the detrusor smooth muscle bundles. Obstructed bladders were significantly less compliant than control bladders (8.3 vs 22.1 mL/cmH2O, P = 0.03). Telemetric cystometry showed that there was no statistically significance difference in mean bladder pressure between obstructed and control pigs (4.8 vs 6.7 cmH2O, P = 0.7), but that each void was longer in the pigs with BOO. CONCLUSION This new model of BOO provides a method of reliably and precisely defining the bladder outlet resistance; it induces the changes classically seen with BOO, including increased bladder mass, increased smooth muscle bundle size and decreased compliance. [source] | ||||||||||