990 research outputs found

    Juxtaposition of Women, Culture, and Nature in Alice Walker's Possessing the Secret of Joy

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    The present paper focuses on the tradition of women's circumsicion in the African tribe of Olinkan in Alice Walker's Possesing the Secret of Joy. The Olinkans are asked by the white settlers to stop women's mutilation, but Olinkan men continue this custom stealthily to ensure their patriarchial dominance. This novel is a complicated juxtaposition of two different types of oppression: one by White male colonizers over an African native land, and the other one by the native Olinkan men over native women. In this juxtaposition women and land are both victims exploited and manipulated by men, no matter Black or White. This novel is also seen as a fertile ground to analyze the dual domination of both nature and women by the Olinkan men and White colonizers who are both trying to impose their androcentric rules that are created to dominate women and land, respectively

    Wide parameter search for isolated pulsars using the Hough transform

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    We use the Hough transform to analyze data from the second science run of the LIGO interferometers, to look for gravitational waves from isolated pulsars. We search over the whole sky and over a large range of frequencies and spin-down parameters. Our search method is based on the Hough transform, which is a semi-coherent, computationally efficient, and robust pattern recognition technique. We also present a validation of the search pipeline using hardware signal injections.Comment: Presented at GWDAW-9 in Annecy, France (Dec. 2004). 11 pages, 5 Figures. To appear in Classical and Quantum Gravit

    Developing a 3D City Digital Twin: Enhancing Walkability through a Green Pedestrian Network (GPN) in the City of Imola, Italy

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    Predominantly, dense historical cities face insufficient pedestrian-level greenery in the urban spaces. The lack of greenery impacts the human thermal comfort on the walking paths, which contributes to a considerable reduction in pedestrian flow rate. This study aims at developing a model to assess pedestrian-level thermal comfort in city environments and then evaluate the feasibility of creating a green pedestrian network (GPN). Imola, as a historical city in Italy with a compact urban pattern, is selected as the case study of this paper. To accomplish this, a three-dimensional digital twin at city scale is developed for the recognition of real-time shade patterns and for designing a GPN in this city. The 3D model of the proposed digital twin is developed in the Rhinoceros platform, and the physiological equivalence temperature (PET) is simulated through EnergyPlus, Honeybee, and Ladybug components in grasshopper. This study provides the city with a digital twin that is capable of examining pedestrian-level thermal comfort for designing a GPN based on real-time PET in the compact urban morphology of Imola. The PET model indicates that during the hottest hour of the 25th of June, pedestrians in open spaces can experience 3  C more than on narrow shaded streets. The results are validated based on in situ datasets that prove the reliability of the developed digital twin for the GPN. It provides urban planners and policy makers with a precise and useful methodology for simulating the effects of pedestrian-level urban greenery on human thermal comfort and also guarantees the functionality of policies in different urban settings

    A review on cement degradation under CO2-rich environment of sequestration projects

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    Global warming arising from the release of greenhouse gasses into the atmosphere is one of the biggest issues attracting a lot of attention. One of the conventional problems in sequestration projects is the degradation of Portland cement due to its exposure to supercritical CO2. This paper gives a review on the laboratory work performed to understand changes in the mechanical and transport properties of cement when it is in a CO2 rich environment. The results obtained indicated that pozzolanic material could be useful in enhancing the cement resistance against CO2, although more studies are still required to confirm this conclusion

    The role of multiplier bounds in fuzzy data envelopment analysis

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    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

    A comparison of energy and thermal performance of rooftop greenhouses and green roofs in Mediterranean climate: A hygrothermal assessment in WuFi

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    In urban areas, a considerable proportion of energy demand is allocated to buildings. Since rooftops constitute one-fourth of all urban surfaces, an increasing amount of attention is paid to achieving the most efficient shapes and component designs compatible with every climate and urban context, for rooftops of varying sizes. In this study, three types of rooftop technologies, namely insulated, green roof, and rooftop greenhouse, are evaluated for energy and thermal performance using computer simulations. Water surface exposure, absorption, and intrusion are the three important factors in the calculation of hygrothermal models that impact energy consumption and building envelope performance; however, a few studies are specifically focused on providing realistic results in multi-dimensional hygrothermal models and the assessment of the impact of moisture in roofing solutions. This paper aims at evaluating the performance of three different roofing technologies through a two-dimensional hygrothermal simulation in software WUFI. To accomplish this, a precise localized microclimate model of a complex urban context on the scale of a neighborhood was employed to evaluate the cooling and heating loads of the buildings, the impact of the water content in the green roof on the thermal behavior of the roof surface, and the feasibility of designing a building with nearly zero cooling needs. A two-story building in the city center of Bologna, Italy is modelled. Simulation results have shown that during the cooling period, the performance of the designed rooftop greenhouse is the most effective by 50% reduction in cooling loads. Besides, the impact of moisture in green roofs has been detected as a negative factor for thermal and energy performance of the building in the Mediterranean climate. The results ultimately highlighted the capability of passively-designed rooftop greenhouses to create a building with nearly zero cooling needs

    The effect of carvacrol on the growth inhibition and genomic destruction in prostatic cancer cells using comet assay technique

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    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

    Parametric Study of Strain Rate Effects on Nanoparticle-Reinforced Polymer Composites

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    Crashworthiness, energy absorption capacity, and safety are important factors in the design of lightweight vehicles made of fiber-reinforced polymer composite (FRP) components. The relatively recent emergence of the nanotechnology industry has presented a novel means to augment the mechanical properties of various materials. As a result, recent attempts have contemplated the use of nanoparticles to further improve the resiliency of resins, especially when resins are used for mating FRP components. Therefore, a comprehensive understanding of the response of nanoreinforced polymer composites, subjected to various rates of loading, is of paramount importance for developing reliable structures. In this paper, the effects of nanoreinforcement on the mechanical response of a commonly used epoxy resin subjected to four different strain rates, are systematically investigated. The results are then compared to those of the neat resin. To characterize the mechanical properties of the nanocomposite, a combination of the strain rate-dependent mechanical (SRDM) model of Goldberg and his coworkers and Halpin-Tsai’s micromechanical approach is employed. Subsequently, a parametric study is conducted to ascertain the influences of particle type and their weight percentage. Finally, the numerical results are compared to the experimental data obtained from testing of the neat and the nanoreinforced epoxy resin

    Retinal photoisomerization versus counterion protonation in light and dark-adapted bacteriorhodopsin and its primary photoproduct

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    Discovered over 50 years ago, bacteriorhodopsin is the first recognized and most widely studied microbial retinal protein. Serving as a light-activated proton pump, it represents the archetypal ion-pumping system. Here we compare the photochemical dynamics of bacteriorhodopsin light and dark-adapted forms with that of the first metastable photocycle intermediate known as “K”. We observe that following thermal double isomerization of retinal in the dark from bio-active all-trans 15-anti to 13-cis, 15-syn, photochemistry proceeds even faster than the ~0.5 ps decay of the former, exhibiting ballistic wave packet curve crossing to the ground state. In contrast, photoexcitation of K containing a 13-cis, 15-anti chromophore leads to markedly multi-exponential excited state decay including much slower stages. QM/MM calculations, aimed to interpret these results, highlight the crucial role of protonation, showing that the classic quadrupole counterion model poorly reproduces spectral data and dynamics. Single protonation of ASP212 rectifies discrepancies and predicts triple ground state structural heterogeneity aligning with experimental observations. These findings prompt a reevaluation of counter ion protonation in bacteriorhodopsin and contribute to the broader understanding of its photochemical dynamics

    Targeted search for continuous gravitational waves: Bayesian versus maximum-likelihood statistics

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    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
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