1,355 research outputs found
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
Damage intensity of gallic acid on prostatic cancer cells lineDu145 by alkaline electrophoresis
زمینه و هدف: سرطان پروستات شایع ترین سرطان در جامعه مردان است. عوامل بسیار زیادی منجر به بروز این بیماری می شود. در عین حال فاکتورهای متعددی به منظور پیشگیری و یا درمان این بیماری شناسایی شده اند. آنتی اکسیدان ها و مخصوصاً ترکیبات پلی فنلی مانند اسید گالیک دارای ظرفیت بالقوه ای از این ویژگی هستند. در این مطالعه با استفاده از تکنیک الکتروفورز قلیایی، اثر اسید گالیک را بر لاین سلول های سرطانی Du145 پروستات مورد مطالعه قرار دادیم. روش بررسی: در این مطالعه تجربی آزمایشگاهی، میزان زیست پذیری سلول های Du145 در مجاورت غلظت های مختلف گالیک اسید، به کمک روش رنگ سنجی تترازولیوم (MTT) اندازه گیری و غلظت مهارکنندگی 50 درصد رشد سلولها (IC50) محاسبه شد. سه غلظت نزدیک به IC50 از داروی اسید گالیک برای 48 ساعت بر سلول های مذکور تیمار شد. پس از انجام الکتروفورز قلیایی تصاویر کامت های ایجاد شده با استفاده از نرم افزار CASP آنالیز شدند. یافته ها: با استفاده از آزمون MTT و بر اساس مدل پروبیت میزان IC50 اسید گالیک برای سلول های Du145 برابر 35 میکرومولار بدست آمد. در آزمون الکتروفورز قلیایی، برای سه غلظت 25،30 و 35 میکرومولار اسیدگالیک، نسبت طول کامت به قطر سلول به ترتیب برابر 1/3±6/7، 2/6±13/8 و 1/2±69/4 بود. نتیجه گیری: گالیک اسید به عنوان یک آنتی اکسیدان قدرتمند در غلظت های نزدیک به IC50 اثر مهاری شدیدی بر رشد سلول های سرطان پروستات (لاین Du145) داشته و با اثر تخریبی بر ژنوم این سلول ها می تواند آپوپتوز را در آنان القاء کند
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The Role of Palliative Surgery for Malignant Bowel Obstruction and Perforation in Advanced Microsatellite Instability-High Colorectal Carcinoma in the Era of Immunotherapy: Case Report.
The role of palliative surgery in the management of acute complications in patients with disseminated malignancy remains controversial given the complexity of assessing acute surgical risk and long-term oncologic outcome. With the emergence of checkpoint blockade immunotherapy, there appears to be an increasing role for historically palliative procedures as a bridge to systemic immunotherapy. This is especially evident in advanced microsatellite instability-high (MSI-H) colorectal cancer where malignant obstruction and fistula formation are more common and where immunotherapy with checkpoint blockade (anti-PD-1/PD-L1, anti-CTLA-4) has a high response rate with potential for favorable oncologic outcomes. We present a series of three patients with MSI-H metastatic colorectal cancer complicated by malignant bowel obstruction and fistula formation, who having progressed on standard chemotherapy, underwent palliative intervention as a bridge to immune checkpoint blockade with durable and clinically meaningful anti-cancer responses. These cases highlight the need to re-evaluate the role of historically palliative operations in the setting of disease progression for immunotherapy-responsive tumors
Entropic forces generated by grafted semiflexible polymers
The entropic force exerted by the Brownian fluctuations of a grafted
semiflexible polymer upon a rigid smooth wall are calculated both analytically
and by Monte Carlo simulations. Such forces are thought to play an important
role for several cellular phenomena, in particular, the physics of
actin-polymerization-driven cell motility and movement of bacteria like
Listeria. In the stiff limit, where the persistence length of the polymer is
larger than its contour length, we find that the entropic force shows scaling
behavior. We identify the characteristic length scales and the explicit form of
the scaling functions. In certain asymptotic regimes we give simple analytical
expressions which describe the full results to a very high numerical accuracy.
Depending on the constraints imposed on the transverse fluctuations of the
filament there are characteristic differences in the functional form of the
entropic forces; in a two-dimensional geometry the entropic force exhibits a
marked peak.Comment: 21 pages, 18 figures, minor misprints correcte
Measurement of Returns-to-Scale using Interval Data Envelopment Analysis Models
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI linkThe economic concept of Returns-to-Scale (RTS) has been intensively studied in the context of Data Envelopment Analysis (DEA). The conventional DEA models that are used for RTS classification require well-defined and accurate data whereas in reality observations gathered from production systems may be characterized by intervals. For instance, the heat losses of the combined production of heat and power (CHP) systems may be within a certain range, hinging on a wide variety of factors such as external temperature and real-time energy demand. Enriching the current literature independently tackling the two problems; interval data and RTS estimation; we develop an overarching evaluation process for estimating RTS of Decision Making Units (DMUs) in Imprecise DEA (IDEA) where the input and output data lie within bounded intervals. In the presence of interval data, we introduce six types of RTS involving increasing, decreasing, constant, non-increasing, non-decreasing and variable RTS. The situation for non-increasing (non-decreasing) RTS is then divided into two partitions; constant or decreasing (constant or increasing) RTS using sensitivity analysis. Additionally, the situation for variable RTS is split into three partitions consisting of constant, decreasing and increasing RTS using sensitivity analysis. Besides, we present the stability region of an observation while preserving its current RTS classification using the optimal values of a set of proposed DEA-based models. The applicability and efficacy of the developed approach is finally studied through two numerical examples and a case study
The role of multiplier bounds in fuzzy data envelopment analysis
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.The non-Archimedean epsilon ε is commonly considered as a lower bound for the dual input weights and output weights in multiplier data envelopment analysis (DEA) models. The amount of ε can be effectively used to differentiate between strongly and weakly efficient decision making units (DMUs). The problem of weak dominance particularly occurs when the reference set is fully or partially defined in terms of fuzzy numbers. In this paper, we propose a new four-step fuzzy DEA method to re-shape weakly efficient frontiers along with revisiting the efficiency score of DMUs in terms of perturbing the weakly efficient frontier. This approach eliminates the non-zero slacks in fuzzy DEA while keeping the strongly efficient frontiers unaltered. In comparing our proposed algorithm to an existing method in the recent literature we show three important flaws in their approach that our method addresses. Finally, we present a numerical example in banking with a combination of crisp and fuzzy data to illustrate the efficacy and advantages of the proposed approach
The effect of carvacrol on the growth inhibition and genomic destruction in prostatic cancer cells using comet assay technique
زمینه و هدف: امروزه، سرطان ها یکی از بزرگترین نگرانی های جوامع بشری است. ترکیبات پلی فنلی و آنتی اکسیدان ها به عنوان یک فاکتور مهم و کلیدی در پیشگیری و یا درمان انواع سرطان ها به خوبی معرفی شده اند. این تحقیق با هدف بررسی اثر کارواکرول به عنوان یک ماده آنتی اکسیدانی قوی بر مهار رشد و میزان تخریب ژنوم رده سلول سرطانی PC3 پروستات انجام شده است. روش بررسی: در این مطالعه تجربی آزمایشگاهی، سلول های سرطانی PC3 پروستات با غلظت های مختلف کارواکرول تیمار و درصد زیست پذیری سلول ها به کمک روش رنگ سنجی تترازولیوم (MTT) اندازه گیری و سپس غلظت مهارکنندگی 50 درصد رشد سلولها (IC50) محاسبه شد.در قدم بعدی، الکتروفورز قلیایی با توجه به IC50 برای سه غلظت 130، 230 و 360 میکرومولار از کارواکرول انجام و 100 عدد تصویر کامت های ایجاد شده با استفاده از نرم افزار CASP آنالیز گردید. یافته ها: بر اساس مدل پروبیت میزان IC50 کارواکرول برای سلول های PC3 360 میکرومولار بدست آمد. در آزمون الکتروفورز قلیایی، نسبت طول کامت به قطر سلول در غلظت های 130، 230 و 360 میکرومولار به ترتیب برابر 2/1±15/9، 4/2±38/7 و 2/0±65/3 درصد مشاهده شد. نتیجه گیری: کارواکرول به عنوان یک ترکیب پلی فنلی موثر در درمان سرطان ها به طور بالقوه ای می تواند ژنوم سلول های PC3 مشتق از سرطان پروستات را تخریب کند. تخریب ژنوم سلول های PC3 در غلظت های نزدیک به IC50 بسیار محسوس تر است
Targeted search for continuous gravitational waves: Bayesian versus maximum-likelihood statistics
We investigate the Bayesian framework for detection of continuous
gravitational waves (GWs) in the context of targeted searches, where the phase
evolution of the GW signal is assumed to be known, while the four amplitude
parameters are unknown. We show that the orthodox maximum-likelihood statistic
(known as F-statistic) can be rediscovered as a Bayes factor with an unphysical
prior in amplitude parameter space. We introduce an alternative detection
statistic ("B-statistic") using the Bayes factor with a more natural amplitude
prior, namely an isotropic probability distribution for the orientation of GW
sources. Monte-Carlo simulations of targeted searches show that the resulting
Bayesian B-statistic is more powerful in the Neyman-Pearson sense (i.e. has a
higher expected detection probability at equal false-alarm probability) than
the frequentist F-statistic.Comment: 12 pages, presented at GWDAW13, to appear in CQ
The impact of smart grid technology on dielectrics and electrical insulation
Delivery of the Smart Grid is a topic of considerable interest within the power industry in general, and the IEEE specifically. This paper presents the smart grid landscape as seen by the IEEE Dielectrics and Electrical Insulation Society (DEIS) Technical Committee on Smart Grids. We define the various facets of smart grid technology, and present an examination of the impacts on dielectrics within power assets. Based on the trajectory of current research in the field, we identify the implications for asset owners and operators at both the device level and the systems level. The paper concludes by identifying areas of dielectrics and insulation research required to fully realize the smart grid concept. The work of the DEIS is fundamental to achieving the goals of a more active, self-managing grid
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