1,322 research outputs found
On Maximum Signless Laplacian Estrada Indices of Graphs with Given Parameters
Signless Laplacian Estrada index of a graph , defined as
, where are the
eigenvalues of the matrix . We
determine the unique graphs with maximum signless Laplacian Estrada indices
among the set of graphs with given number of cut edges, pendent vertices,
(vertex) connectivity and edge connectivity.Comment: 14 pages, 3 figure
Cryptosporidium infection in patients with gastroenteritis in Sari, Iran
Background: Cryptosporidiosis is a common coccidian parasite infection in patients with diarrhea that has worldwide distribution especially in developed countries. Therefore, the aim of this study was to determine the occurrence of Cryptosporidium infection in patients with gastroenteritis admitted to hospitals of Mazandaran University of Medical Sciences by parasitological and molecular methods in Sari, Iran. Methods: Stool samples were collected from 348 patients with gastroenteritis admitted to the hospitals of Medical University in the Sari and Ghaemshahr cities in Mazandaran Province, Northern Iran in 2010-2011. Oocysts of Cryptosporidium identified using Formalin-Ether concentration method and stained by Aacidfast staining (AFS) and Auramine phenol fluorescence (APF). Genomic DAN extracted from microscopically positive samples and nested PCR -RFLP by using SSU rRNA that identifies of the species of cryptosporidium. Results: In 348 patients with gastroenteritis, the most clinical symptoms were diarrhea, nausea, vomiting, dehydration, fever and weight loss. 2.3% (8 cases) of diarrheal samples tested by both microscopy and molecular methods were positive for the presence of cryptosporidium. Nested PCR products yielded unique bands of 846 bp, correspond to cryptosporidium. Species diagnosis carried out by digesting the secondary PCR product with SspI restriction enzyme, which noted 3 clearly bands of 449, 254, and 108 bp correspond to Cryptosporidium spp. Conclusion: The results of present study on Cryptosporidium spp. in this area can make a background data for control programs and further molecular analyses. Thus, further work needs to determine the origin of Cryptosporidium species in this area
Improved Stack-Slide Searches for Gravitational-Wave Pulsars
We formulate and optimize a computational search strategy for detecting
gravitational waves from isolated, previously-unknown neutron stars (that is,
neutron stars with unknown sky positions, spin frequencies, and spin-down
parameters). It is well known that fully coherent searches over the relevant
parameter-space volumes are not computationally feasible, and so more
computationally efficient methods are called for. The first step in this
direction was taken by Brady & Creighton (2000), who proposed and optimized a
two-stage, stack-slide search algorithm. We generalize and otherwise improve
upon the Brady-Creighton scheme in several ways. Like Brady & Creighton, we
consider a stack-slide scheme, but here with an arbitrary number of
semi-coherent stages and with a coherent follow-up stage at the end. We find
that searches with three semi-coherent stages are significantly more efficient
than two-stage searches (requiring about 2-5 times less computational power for
the same sensitivity) and are only slightly less efficient than searches with
four or more stages. We calculate the signal-to-noise ratio required for
detection, as a function of computing power and neutron star spin-down-age,
using our optimized searches.Comment: 19 pages, 7 figures, RevTeX
Upper bounds on position error of a single location estimate in wireless sensor networks
This paper studies upper bounds on the position error for a single estimate of an unknown target node position based on distance estimates in wireless sensor networks. In this study, we investigate a number of approaches to confine the target node position to bounded sets for different scenarios. Firstly, if at least one distance estimate error is positive, we derive a simple, but potentially loose upper bound, which is always valid. In addition assuming that the probability density of measurement noise is nonzero for positive values and a sufficiently large number of distance estimates are available, we propose an upper bound, which is valid with high probability. Secondly, if a reasonable lower bound on negative measurement errors is known a priori, we manipulate the distance estimates to obtain a new set with positive measurement errors. In general, we formulate bounds as nonconvex optimization problems. To solve the problems, we employ a relaxation technique and obtain semidefinite programs. We also propose a simple approach to find the bounds in closed forms. Simulation results show reasonable tightness for different bounds in various situations. © 2014 Gholami et al.; licensee Springer
Data on experimental investigation of Methyl Ester Sulphonate and nanopolystyrene for rheology improvement and filtration loss control of water-based drilling fluid
Data presented in this article focused on the application of Methyl Ester Sulphonate (MES) surfactant and nanopolystyrene in water based drilling fluid. Data from rheology study using Bingham and Power law models showed that the synergy of MES and nanopolystyrene improved the formulated drilling fluid. Filtration study under LPLT and HPHT conditions showed that MES and nanopolystyrene drilling fluid reduced filtration loss by 50.7% at LPLT and 61.1% at HPHT conditions. These filtration data were validated by filter cake permeability and scanning electron microscope images
A survey of patient safety culture: A tool for improving patient safety in healthcare providers service organizations
Background and aims: Patient safety is one of the main factors in quality of services provided by a health system. Patient safety culture plays a key role in improvement of patient safety, reduction of medical errors, and prevention of adverse events in health care organizations. Thereby, the present study is aimed to survey patient safety culture in hospitals of Neyshabur University of Medical Sciences. Methods: This research was a cross sectional study that conducted on all qualified staff of hospitals affiliated with Neyshabur University of Medical Sciences in 2013. Hospital Survey of Patient Safety Culture (HSOPSC) questionnaire was used to assess patient safety culture. The collected data were analyzed in SPSS (16), using Chi-Square test and logistic regression model. Results: Total score average of patient safety culture was 25.50±9.52. The results showed that among the twelve dimensions the highest and lowest scores were obtained by the supervisor/ manager expectations & actions promoting patient safety (score rate 45) and the reporting frequency of adverse events (score rate 15) respectively According to logistic regression model there was also significant relationship between the patient safety culture and direct contact with the patient, employment duration in hospital, and current unit (p<0.05). Conclusion: Total average of patient safety culture and scores of all twelve dimensions were lower than the acceptable criteria. Patient safety culture in the studied hospitals urgently needs enhancement and improvement. So, creating policies to institutionalize and enhance patient safety culture among the staffs are recommended
Application of seismic attributes in structural study and fracture analysis of DQ oil field, Iran
The determination of the most unstable areas in oil fields is critical for addressing engineering problems of wellbore and sand production as well as geologic problems such as understanding dynamic constraints on hydrocarbon migration and fracture permeability. In this research work, coherency seismic attribute has been used for the determination of the most critical areas in terms of drilling stabilities in the DQ oil field, Iran. The results obtained have shown that the (1) predominant features are the SSE–NNW and N–S trends (2) the central part of the DQ structure shows the highest concentration of segment bundles, (3) the segment bundles seem to be aligned along some lineaments oriented SE–NW and SSE–NNW, and (4) on the eastern and western margins of the map there is an anomalous concentration of segments oriented E–W. It can be concluded that coherency attribute is a valuable tool for structural analysis highlighting those areas containing unstable features
The effect of drought stress and exogenous abscisic acid on growth, protein content and antioxidative enzyme activity in saffron (Crocus sativus L.)
This study was carried out to investigate the effect of drought and abscisic acid (ABA) on growth, protein content and antioxidative enzyme activity in leaves, roots and corms of Crocus sativus L. A comparative study of sample and control showed that leaf relative water content (RWC), length and number of leaves decreased due to drought and ABA when compared to control. Drought and ABA were effective in increasing root length in comparison to control. Though drought and ABA improved the protein content in corms, leaves and roots, maximum protein content was detected in corms. Drought and ABA increased superoxide dismutase (SOD) and peroxidase (POX) activitiy in roots, leaves and corms when compared to that of the control. The highest SOD activity was observed in the roots, followed by leaves and corms, respectively. Furthermore, highest POX activity was observed in roots.Key words: Drought, ABA-treatment, Crocus sativus, peroxidase, superoxide dismutase
Validity of naked eye single tube red cell osmotic fragility test (NESTROFT) in screening of beta-thalassemia trait
زمینه و هدف: تالاسمی متداولترین اختلال تک ژنی است که رهایی از آن از طریق درمان قطعی ممکن نبوده و مستلزم پیشگیری از طریق به کارگیری یک روش قابل اعتماد و کم هزینه برای غربالگری ناقلین و در مرحله بعد ارایه آموزش، مشاوره ژنتیک، تشخیص قبل از تولد و خاتمه انتخابی به زندگی جنین های مبتلا به این اختلال است. هدف از این مطالعه ارزیابی تست اسموتیک تک لوله ای چشمی گلبول های قرمز (NESTROFT) به عنوان یک تست غربالگری در راستای کشف مبتلایان به بتاتالاسمی مینور بود. روش بررسی: در این مطالعه توصیفی- تحلیلی، تست NESTROFT بر روی 158 نفر متشکل از 51 نفر فرزندان والدینی که حداقل یکی از بچه های آنها دارای بتا تالاسمی ماژور بود، 51 فرد طبیعی و 56 فرد از مبتلایان به فقر آهن انجام شد. داده های حاصل به کمک آزمون های آماری آنالیز واریانس یک راهه و آزمون تعقیبی دانت تجزیه و تحلیل گردید. یافته ها: بر اساس نتایج، حساسیت و ارزش اخباری منفی تست NESTROFT 100 بوده و با توجه به 14 مورد نتیجه مثبت کاذب ناشی از فقر آهن، ویژگی آن 9/86 و ارزش اخباری مثبت تست 5/78 می باشد. نتیجه گیری: تست NESTROFTدر عین کم هزینه بودن و سهولت انجام، حساسیت بالایی برای کشف بتا تالاسمی مینور داشته و می توان از آن در کشورهای در حال توسعه با منابع اقتصادی و تکنیکی محدود از قبیل ایران در مقیاس وسیع جهت غربالگری توده ای استفاده نمود
[H2-Cryptand 222]2+(Br3 –)2 as a Tribromide-Type Catalyst for the Trimethylsilylation/Tetrahydropyranylation of Alcohols
A stable organic tribromide, [H2-cryptand 222]2+(Br3–)2 was utilized as an active catalyst for the trimethylsilylation/tetrahydropyranylation of alcohols. The method is general for the preparation of OH-protected aliphatic (acyclic and cyclic), aromatic, primary, secondary and tertiary alcohols.Keywords: [H2-cryptand 222]2+(Br3–)2, trimethylsilylation, tetrahydropyranylation, alcohols, tribromide, TMS-ether, THP-ethe
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