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Sample geometric mean versus sample median in closed form framework of seismic reliability evaluation: a case study comparison

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Earthquake Engineering and Engineering Vibration 2019年第1期18卷 187-201页

作者： m.Abyani B.Asgarian m.zarrin Faculty of Civil Engineering K.N.Toosi University of Technology

Earthquake engineers have made a lot of efforts to derive a comprehensive set of closed form expressions for performance evaluation of frames, which are already presented in guidelines such as SAC/FEmA. These analytical expressions have been developed to estimate the annual probability of exceeding a limit state. In the process of such seismic assessments, some essential assumptions are adopted to simplify the process. One of these fundamental assumptions declares that drift demand at any seismic intensity level follows a lognormal distribution around its median. To investigate the validity of this assumption, this paper describes a case study of the types of errors that could be produced by using the sample median as the central tendency. Based on the maximum Likelihood Estimation method as well as other statistical evidence, this paper proposes the use of the sample geometric mean instead of the sample median for the central tendency. Further, the results of seismic reliability evaluations of 4 sample frames are compared based on utilizing both the geometric mean and the sample median. In this process, both first and second order power law fits of the hazard curve are implemented to compare the effects of hazard estimation and the selection of the central tendency on the final results. It is observed in the application example that the sample geometric mean could lead to more accurate results.

关键词： seismic reliability closed-form expression SAC/FEmA limit state median geometric mean

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Impact of metal polluted sewage water on soil nematode assemblages in agricultural settings of Aligarh,India

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Soil Ecology Letters 2024年第1期6卷 61-75页

作者： mohammed F.S.A.Ghanem Shahid Afzal Humira Nesar zarrin Imran Wasim Ahmad Nematode Biodiversity Research Lab Department of ZoologyAligarh Muslim UniversityAligarh 202002India

Sewage water in agriculture threatens human health and soil ecosystems through metal *** show promise as bioindicators of soil health due to their abundance and position in soil food ***-polluted water decreased abundance of certain nematode groups and Sigma maturity *** pollution positively affected nematode groups with r-selected life *** water has been inappropriately used in agriculture,posing possible threats to human health and the soil ecosystems by its constituent pollutants,especially heavy *** evaluation of its influences on soil biomes needs to consider the response of soil *** soil organisms,nematodes are seen as the best promising candidates for bioindicators of soil *** in,we collected soil samples from fresh water irrigated field from three sites(S1,S2 and S3)and sewage water irrigated distance gradient(5 m-40 m),to assess the influence of metal(Cu,Zn,Cd,mn,Pb)polluted water on various characteristics of nematode *** results indicated that the heavy metals decreased the abundance of C-p3 nematodes,herbivores,and predatory nematodes as well as sigma maturity index,whereas,C-p1,C-p2,bacterivore and fungivore nematodes abundance and diversity positively responded to the metal ***,nematode genera with r-selected life cycle were positively affected and those with K-selected life cycle were negatively affected by metal *** nematode community has potential to be used as indicator of pollution stress in agricultural soils to check soil health and sustainability.

关键词： heavy metals sewage irigation agriculture nematodes bioindicators

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Lattice models of Finite Fields

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Advances in Pure mathematics 2017年第9期7卷 451-466页

作者： Lucian m. Ionescu[lmiones@ilstu.edu] mina m. zarrin mathematics Department Illinois State University Normal IL USA

Finite fields form an important chapter in abstract algebra, and mathematics in general, yet the traditional expositions, part of Abstract Algebra courses, focus on the axiomatic presentation, while Ramification Theory in Algebraic Number Theory, making a suited topic for their applications, is usually a separated course. We aim to provide a geometric and intuitive model for finite fields, involving algebraic numbers, in order to make them accessible and interesting to a much larger audience, and bridging the above mentioned gap. Such lattice models of finite fields provide a good basis for later developing their study in a more concrete way, including decomposition of primes in number fields, Frobenius elements, and Frobenius lifts, allowing to approach more advanced topics, such as Artin reciprocity law and Weil Conjectures, while keeping the exposition to the concrete level of familiar number systems. Examples are provided, intended for an undergraduate audience in the first place.

关键词： Finite Fields Algebraic Number Fields Ramification Theory Frobenius Element Congruence Zeta Function Weil Zero

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Flow diversion covering the m1 origin as a last resort

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Stroke & Vascular Neurology 2019年第3期4卷 141-147页

作者： Li-mei Lin matthew T Bender Geoffrey P Colby Bowen Jiang Jessica K Campos David A zarrin Robert W C Young Risheng Xu Justin m Caplan Judy Huang Rafael J Tamargo Alexander L Coon Department of Neurosurgery University of California IrvineOrangeCaliforniaUSA Department of Neurosurgery Johns Hopkins University School of MedicineBaltimoreMarylandUSA Department of Neurosurgery University of California Los AngelesLos AngelesCaliforniaUSA

Introduction Internal carotid artery termination(ICAT)and proximal A1 aneurysms can be challenging for open surgical clipping or endovascular *** with flow diversion covering the middle cerebral artery(mCA),an end vessel supplying a terminal circulation,has not been *** A prospective,Institutional Review Board-approved database was analysed for patients with pipeline embolisation device(PED)placement from the anterior cerebral artery(ACA)to the ICA during cerebral aneurysm *** Nine cases were identified,including five proximal A1,three posterior communicating artery and one ICAT aneurysm *** aneurysm size was 8.3 mm(range 3-17),with 67%saccular and 78%*** indication for treatment was significant dome irregularity(44%),recurrence or enlargement(33%),underlying collagen vascular disorder(11%)and traumatic pseudoaneurysm(11%).Preservation of the ipsilateral ACA(with PED placed in A1)was performed when the anterior communicating artery(67%)or contralateral A1(33%)were absent on *** coiling was done in four cases(44%).There was one major stroke leading to mortality(11%)and one minor stroke(11%).Clinical follow-up was 27 months on ***-up digital subtraction angiography(average interval 15 months)showed complete aneurysm obliteration(88%)or dome occlusion with entry remnant(12%).The jailed mCA showed minimal or mild delay(primarily anterograde flow)in 75%of cases and significant delay(reliance primarily on ACA and external carotid artery collaterals)in 25%.Conclusions Covering the mCA with a flow diverting stent should be reserved for select rare *** attention to blood pressure augmentation during the periprocedural period is necessary to minimise potential ischaemic compromise.

关键词： primarily resort sided

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