1,111 research outputs found

    Investigation of Io's Auroral Hiss Emissions Due To Its Motion in Jupiter's Magnetosphere

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    The left-hand side of the auroral hiss emission observed by Galileo has a frequency time shaped very similar to the funnel shape observed in the earth's auroral region. This close similarity indicates that we can use the whistler-mode propagation near resonance cone to locate the emission source. In this paper the general characteristic of the whistler mode are discussed. Then the position of the emission source has been investigated using a geometry method that takes into account the Galileo's trajectory. Initially it is assumed the source is a point. Then the possibility of sheet source aligned along the magnetic field lines which are tangent to the surface of Io is investigated. Both of two types of sources show that the whistler mode radiation originates very close to the surface of the Io

    Biased random satisfiability problems: From easy to hard instances

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    In this paper we study biased random K-SAT problems in which each logical variable is negated with probability pp. This generalization provides us a crossover from easy to hard problems and would help us in a better understanding of the typical complexity of random K-SAT problems. The exact solution of 1-SAT case is given. The critical point of K-SAT problems and results of replica method are derived in the replica symmetry framework. It is found that in this approximation αcp(K1)\alpha_c \propto p^{-(K-1)} for p0p\to 0. Solving numerically the survey propagation equations for K=3 we find that for p<p0.17p<p^* \sim 0.17 there is no replica symmetry breaking and still the SAT-UNSAT transition is discontinuous.Comment: 17 pages, 8 figure

    Higher Order and boundary Scaling Fields in the Abelian Sandpile Model

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    The Abelian Sandpile Model (ASM) is a paradigm of self-organized criticality (SOC) which is related to c=2c=-2 conformal field theory. The conformal fields corresponding to some height clusters have been suggested before. Here we derive the first corrections to such fields, in a field theoretical approach, when the lattice parameter is non-vanishing and consider them in the presence of a boundary.Comment: 7 pages, no figure

    Patterned and Disordered Continuous Abelian Sandpile Model

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    We study critical properties of the continuous Abelian sandpile model with anisotropies in toppling rules that produce ordered patterns on it. Also we consider the continuous directed sandpile model perturbed by a weak quenched randomness and study critical behavior of the model using perturbative conformal field theory and show the model has a new random fixed point.Comment: 11 Pages, 6 figure

    Morphology of proximal tibia in iranian population and its correlation with available prostheses

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    Background: Total knee arthroplasty is a complex procedure aiming to relieve pain and improve function. It is critical to select prosthesis that best cover the bone surfaces. Ethnicity may affect fitness of the components mainly designed for Caucasian populations. This study aimed to evaluate morphometric features of proximal tibia in Iranian population. Methods: During 2013, 150 consecutive patients (96 males and 54 females) form orthopedics department of Rasoul-Akram hospital with knee CT scan were randomly enrolled. We entered cases with apparent normal extremity alignment and bone maturity. Cases with history of fracture or conditions affecting knee profile were excluded. Standard cuts were simulated on CT scan. Anteroposterior (AP), mediolateral (ML) and aspect ratio (ML/AP) were measured for general morphology. Medial and lateral AP distance of tibia and their distance to tibial center were measured for checking symmetry. Results: Mean age was 43.0± 10.4 years (rang 11-80). Males showed significantly larger values in ML dimension and aspect ratio than females under a given AP value (p<0.001). However, the aspect ratio was suggestive of similar configuration of proximal tibia profiles among genders. Totally, close correlations were observed among simulated cuts and size-matched tibial components of the prostheses. However, better coverage was provided by some brands via designing interchangeable components for a given dimension. Medial and lateral condyles of tibia were almost symmetrical. Conclusion: Our findings indicated that some alterations in the shape of the components are needed to provide optimal coverage in Iranian population. We propose symmetrical configuration in designing tibial components as well

    An intelligent risk detection model to improve decision efficiency in healthcare contexts: the case of paediatric congenital heart disease

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    Objectives: Healthcare is an information rich industry where successful outcomes require the processing of multi-spectral data and sound decision making. The exponential growth of data and big data issues coupled with a rapid increase of service demands in healthcare contexts today, requires a robust framework enabled by IT (information technology) solutions as well as real-time service handling in order to ensure superior decision making and successful healthcare outcomes. Such a context is appropriate for the application of a real time intelligent risk detection decision support systems using business analytics and data science technologies. To illustrate the power and potential of business analytics and data science technologies in healthcare decision making scenarios, the use of an Intelligent Risk Detection (IRD) Model is proffered for the context of Congenital Heart Disease (CHD) in children, an area which requires complex high risk decisions that need to be made expeditiously and accurately in order to ensure successful healthcare outcomes. The main aim of this research is reducing burden of complex surgeries in patients, their family and society through early detecting of surgical risk factors prior to surgery. The research question is: How can an intelligent risk detection (IRD) Model be developed in the healthcare contexts? Method: This study is exploratory in nature and endeavours to explore the main components, barriers, issues and requirement to design and develop an Intelligent Risk Detection framework to be applied to healthcare contexts. In this research a qualitative approach using an exemplar data site as a single case study is adapted to address research objectives and to answer the research question. Data collection is through semi-structured interviews, questionnaires, observation and the analysis of documents, files and data bases from the study site. After conducting the data collection phase thematic analysis is applied to analyse all collected qualitative data. Results: This study has a significant contribution to practice and theory; namely confirming a role for business analytics and data science technologies in healthcare contexts. Also, this research serves to demonstrate that the selection of risk detection, prediction by data mining tools as one of the data science techniques and then decision support are very important for decision making in the complex surgeries. IRD, in practice, can also be used as a training tool to train nurses and medical students to detect the CHD surgery risk factors and their impact on surgery outcomes. Moreover, it can also provide decision support to assist doctors to make better clinical and surgical decisions or at least provide a second opinion. Furthermore, IRD can be used as a knowledge sharing and information transferring tools between clinicians, between clinicians and patients or their families and also between patients with the other patients. In this study also main components, barriers, issues and requirement to design and develop an Intelligent Risk Detection solution are explored and a comprehensive real time Intelligent Risk Detection Model in the healthcare context is designed

    Simplifying Random Satisfiability Problem by Removing Frustrating Interactions

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    How can we remove some interactions in a constraint satisfaction problem (CSP) such that it still remains satisfiable? In this paper we study a modified survey propagation algorithm that enables us to address this question for a prototypical CSP, i.e. random K-satisfiability problem. The average number of removed interactions is controlled by a tuning parameter in the algorithm. If the original problem is satisfiable then we are able to construct satisfiable subproblems ranging from the original one to a minimal one with minimum possible number of interactions. The minimal satisfiable subproblems will provide directly the solutions of the original problem.Comment: 21 pages, 16 figure

    Treatment of cervicofacial actinomycosis: a report of 19 cases and review of literature

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    Objectives: Actinomycosis is a chronic suppurative granulomatous infection caused by the Actinomyces genus. Orocervicofacial actinomycosis is the most common form of the disease, seen in up to 55% of cases. All forms of actinomycosis are treated with high doses of intravenous penicillin G over two to six weeks, followed by oral penicillin V. Large studies on cervicofacial actinomycosis are lacking. Therefore proper guidelines for treatment and treatment duration are difficult to establish. The aim of this study is to establish effective treatment and treatment duration for orocervicofacial actinomycosis. Study design: A Pubmed and Embase search was performed with the focus on treatment and treatment duration for cervicofacial actinomycosis. The hospital records of all patients presenting to our department with head and neck infection from January 2000 to December 2010 were reviewed, retrospectively. The following data were collected: age, gender, clinical presentation, aetiology, duration of symptoms, microbiological findings, treatment, and duration of treatment. The treatment and treatment duration is subsequently compared to the literature. Results: The literature search provided 12 studies meeting the inclusion criteria. All studies were retrospective in nature. Penicillin or amoxicillin/clavulanic acid are the preferred antibiotic regimens found in the literature. Most of our patients were treated with a combination of penicillin G 12 million units/day and metronidazol 500 mg 3/ day, most commonly for a duration of 1 - 4 weeks, being shorter than the 3 - 52 weeks reported in the literature. Conclusion: When actinomycosis is suspected, our review has shown that a surgical approach in combination with intravenous penicillin and metronidazol until clinical improvement is seen, followed by oral antibiotics for 2 - 4 weeks is generally efficient

    ZARISKI-LIKE SPACES OF CERTAIN MODULES

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    Abstract. Let R be a commutative ring with identity and M be a unitary R-module. The primary-like spectrum Spec L (M ) is the collection of all primary-like submodules Q such that M/Q is a primeful R-module. Here, M is defined to be RSP if rad(Q) is a prime submodule for all Q ∈ Spec L (M ). This class contains the family of multiplication modules properly. The purpose of this paper is to introduce and investigates a new Zariski space of an RSP module, called a Zariski-like space. In particular, we provide conditions under which the Zariski-like space of a multiplication module has a subtractive basis

    Survival rate of patients with bladder cancer in Yazd, central province of Iran

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    Abstract Background: Bladder cancer is the ninth most commonly diagnosed malignancy worldwide. The trend of bladder cancer incidence and mortality is rising in Iran. This study was aimed to evaluate the survival rate of patients with bladder cancer in Yazd province, Iran. Methods: In this retrospective cohort study, data were collected from 340 patients suffering from bladder cancer referred to Shahid Rahnemon and Shohada-Kargar Hospitals in Yazd province, Iran between April, 2001 and March, 2012. Variables included age, gender, stage of cancer, place of residence and type of treatment. The Kaplan-Meier and Cox regression analyses were used to evaluate the relationship between each variable and survival time. A P value less than 0.05 was considered significant. Results: The mean age of total patients was 65.8 ± 13.6 years, and their mean survival time was 68.55 ± 6.05 months. Cumulative survival rates at the end of 1, 3, and 5 years in bladder cancer patients were 91%, 58%, and 51.4%, respectively. A statistically significant association was found between age (P = 0.005), stage of disease (P = 0.0003), type of treatment (P = 0.0003) and survival time of patients. Data showed no significant correlation between age, gender, place of residence and patients’ survival. Conclusions: The survival of patients suffering from bladder cancer in this study was less than other reports. Patients’age and cancer stage were the effective factors in survival time. Continuous screening of older people for cancer diagnosis in early stages is seemed to improve survival in patients. Keywords: Bladder; Cancer; Survival Rate; Ira
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