6,636 research outputs found
Fractional spin through quatum (super)Virasoro algebras
The splitting of a -deformed boson, in the Q\to q=e^{\frac{\QTR{rm}{2\pi
i}}{\QTR{rm}{k}}} limit, is discussed. The equivalence between a -fermion
and an ordinary one is established. The properties of the quantum
(super)Virasoro algebras when their deformation parameter goes to a root of
unity, are investigated. These properties are shown to be related to fractional
supersymmetry and -fermionic spin
Generalization bounds for averaged classifiers
We study a simple learning algorithm for binary classification. Instead of
predicting with the best hypothesis in the hypothesis class, that is, the
hypothesis that minimizes the training error, our algorithm predicts with a
weighted average of all hypotheses, weighted exponentially with respect to
their training error. We show that the prediction of this algorithm is much
more stable than the prediction of an algorithm that predicts with the best
hypothesis. By allowing the algorithm to abstain from predicting on some
examples, we show that the predictions it makes when it does not abstain are
very reliable. Finally, we show that the probability that the algorithm
abstains is comparable to the generalization error of the best hypothesis in
the class.Comment: Published by the Institute of Mathematical Statistics
(http://www.imstat.org) in the Annals of Statistics
(http://www.imstat.org/aos/) at http://dx.doi.org/10.1214/00905360400000005
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Simulation discounted cash flow valuation for internet companies
Discounted cash flow (DCF) is the most accepted approach for company valuation. It is well grounded in theory and practice. However, the DCF approach, which is commonly used for traditional companies valuation, presents a number of serious weaknesses within the Internet companiesâ context. One of these weaknesses is tackling the uncertainty that characterize future cash flows of these companies. Specifically DCF assumes that future cash flow streams are highly predictable. The effects of uncertainty are therefore tackled implicitly by discounting the expected value of the cash flows at a risk-adjusted interest rate. However, under uncertainty, future cash flows of these companies can no longer be characterized by a single value but rather by a range of values of its possible consequences. This paper looks at the way in which uncertainty can be incorporated into the traditional DCF approach so that the latter, which is otherwise conceptually sound, becomes relevant. This is done by recognizing that the DCF input variables are uncertain and will have a probability distribution pertaining to each of them. Thus by utilizing a probability-based valuation model (using Monte Carlo Simulation) it is possible to incorporate uncertainty into the analysis and address the shortcomings of the current model. The MC simulation assigns a range of values in order to cope with uncertainty underlies each key cash flow variable. The process leads to a probability distribution of the valuation criterion used, giving investors a quantitative measure of risk involved
Reflections on The Image of Green Buildings: An Ethnographic Evaluation of A âLEEDâ Certified Elementary School
Davidson Elementary School is the first LEED certified school building in Tucson, Arizona, the school has been designed and built as a green setting based on the goals of the architect, teachers, parents and a community that has long suffered from the moldy old Davidson school building. Yet by looking at the new building and comparing it with conventional schools with similar function and size in Tucson, Arizona, one questions whether the users can distinguish differences which might be related to the buildingâs greenness? Is the same true for many other LEED rated green school buildings in other parts of United States? The present paper asks whether the image of a building, and even an integrated pedagogy in the case of schools, shouldnât more actively promote the meaning of sustainability. The present case is an ethnographic study has been done at Davidson Elementary School during the authorâs sabbatical at University of Arizona in 2010. The study included analysis for the images of the building as well as interviews with the principal, teachers, administrative staff, 4th and 5th grade students and parents. The ethnographic evaluation shows that Davidson Elementary Buildings offers limited use of symbolic meanings to foster belief about sustainability; at the same time it conveys some negative meanings to laypeople, obviously hindering a possible sustainable relationship between people and environment. The examination of the cultural expression of buildingsâ green features and the meanings acquired from them at Davidson School provides a novel ethnographic evaluation of green building design intentions
Intraduodenal sarcoma recurrence of retroperitoneal origin: an unusual cause for a duodenal obstruction.
Soft tissue sarcomas are uncommon tumors, and intraduodenal soft tissue sarcoma manifestation is even more rare. Only three cases of intraduodenal sarcomas have been reported in the literature thus far. Here, we report a case of an intraduodenal recurrence of a retroperitoneal sarcoma causing bowel obstruction. This unusual recurrence pattern likely relates to the patient's previous resection and radiation treatment, and highlights the benefits, limitations and follow-up strategies after multimodality treatment
Handling Sexuality Concerns in Women with Gynecological Cancer: Egyptian Nurse's Knowledge and Attitudes
Sexuality is an important part of normal human functioning. Gynecological cancer diagnosis and treatment has devastating effect on Sexual issues. Study aim was to investigate Oncology Nurses knowledge and attitudes in Relation to Provision of Sexual Health Care to Women Diagnosed with Gynecological Cancer. The study setting was conducted at oncology center, at Mansoura University Hospitals after obtaining hospital director approval. A Subject was consisted of 72 nurses who worked in gynecological oncology department. Tools: four tools were used by the researchers to collect pertinent data consisted of 1st The Self Administered Structured Schedule, 2nd tool, Sexual Health Care ScaleâAttitude, 3rd tool, Facilitators about Sexuality Issue Discussion in nursing practice and 4th tool, Barriers about Sexuality Issue Discussion in Nursing Practice. Results revealed that 100% of nurses were having poor knowledge score regarding sexual health care with mean score 7.3 ±2.5. There was statistically significant relation between knowledge score and discomfort in providing sexual health care and Afraid of collegeâs negative response (P< 0.05). While there were no statistical significant relation between knowledge score and Feeling uncertain about patientâs acceptance and Lack of environmental support (P> 0.05). Majority of nurses reported that limited resources, patient embarrassment, staff shortages, patients having more things to be concerned about than having sex, inadequate education preparation, are the most important barriers to provide health sexual education. Provisions of relevant training, availability of private environment, having good nurse patient relationship, good communication are factors which facilitate provision of sexual health care. Conclusion oncology nurses have poor knowledge score and decrease feeling of discomfort domain was the most representative nurses attitude in provision of sexual health care, there are many of issues act as barriers and facilitators affecting nurses for providing sexual health care. Recommendations It is important to put sexual health education into the curriculum of nursing, in order to assess the sexual health of patients within the health care system, continuing education activities and availability of education materials could assist nurses to adequately address sexual concerns while caring for patients with cancer and More research is needed on training of the nurses to overcome the barriers and guidelines or procedures in place for dealing with sexuality-related issues with patients. Key words: Sexuality Concerns, Gynecological Cancer, Egyptian Nurses, Knowledge, Attitude
Diffusion Of Color-Centers Generated By 2-Photon Absorption At 532-Nm In Cubic Zirconia
We have recently reported the formation of color centers in stabilized cubic zirconia (ZrO2, 18% Y2O3) by twoâphoton absorption at 532 nm. Here we present the results of measurements of the transmission of the colored samples as a function of time at room temperature. The results are found to be in good agreement with theory that assumes the color centers diffuse out of the irradiated region. The initial distribution of centers is assumed to have a Gaussian profile. For this model, the diffusion equation was solved exactly and the diffusion constant obtained (âŒ3.4Ă10â8 cm2/s)
Sensitivity analysis of permeability parameters of bovine nucleus pulposus obtained through inverse fitting of the nonlinear biphasic equation : effect of sampling strategy
Permeability controls the fluid flow into and out of soft tissue, and plays an important role in maintaining the health status of such tissue. Accurate determination of the parameters that define permeability is important for the interpretation of models that incorporate such processes. This paper describes the determination of strain-dependent permeability parameters from the nonlinear biphasic equation from experimental data of different sampling frequencies using the NelderâMead simplex method. The ability of this method to determine the global optimum was assessed by constructing the whole manifold arising from possible parameter combinations. Many parameter combinations yielded similar fits with the NelderâMead algorithm able to identify the global maximum within the resolution of the manifold. Furthermore, the sampling strategy affected the optimum values of the permeability parameters. Therefore, permeability parameter estimations arising from inverse methods should be utilised with the knowledge that they come with large confidence intervals
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