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Continuous-cyclic variations in the b-value of the earthquake frequency-magnitude distribution

Earthquake Science 2013年第5期26卷 301-320页

作者： Z.h.El-Isa Geology Department University of Jordan

Seismicity of the Earth （m ≥ 4.5） was compiled from NEIC, IRIS and ISC catalogues and used to compute b-value based on various time windows. It is found that continuous cyclic b-variations occur on both long and short time scales, the latter being of much higher value and sometimes in excess of 0.7 of the absolute b-value. These variations occur not only yearly or monthly, but also daily. Before the occurrence of large earthquakes, b-values start increasing with variable gradients that are affected by foreshocks. In some cases, the gradient is reduced to zero or to a negative value a few days before the earthquake occurrence. In general, calculated b-values attain maxima 1 day before large earthquakes and minima soon after their occurrence. Both linear regression and maximum likelihood methods give correlatable, but variable results. It is found that an expanding time window technique from a fixed starting point is more effective in the study of b-variations. The calculated b-variations for the whole Earth, its hemispheres, quadrants and the epicentral regions of some large earthquakes are of both local and regional character, which may indicate that in such cases, the geodynamic processes acting within a certain region have a much regional effect within the Earth. The b-variations have long been known to vary with a number of local and regional factors including tectonic stresses. The results reported here indicate that geotectonic stress remains the most significant factor that controls b-variations. It is found that for earthquakes with mw ≥ 7, an increase of about 0.20 in the b-value implies a stress increase that will result in an earthquake with a magnitude one unit higher.

关键词： Earthquake frequency-magnitude b-value Temporal b-variation Spatial b-variation

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何种干预可以有效减少慢性疼痛患者阿片类药物的摄入?

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英国医学杂志中文版 2019年第2期22卷 117-121页

作者： h Sandhu m Underwood AD Furlan J Noyes S Eldabe 景晨萌(译) Warwick Clinical Trials Unit Warwick Medical SchoolUK Department of medicine University of TorontoCanada The James Cook University hospital MiddlesbroughUK 北京新世纪妇儿医院麻醉科

阿片处方通常适用于非癌性慢性疼痛患者短期镇痛如果长期使用.大部分患者会发展成药物耐受,则疼痛加重,进而门诊医生递增药物剂量(图1)美国阿片处方药的销量在2000至2010年间成倍增长媒体报道过各种危害,药物依赖、服药过量导致意外身... 详细信息

阿片处方通常适用于非癌性慢性疼痛患者短期镇痛如果长期使用.大部分患者会发展成药物耐受,则疼痛加重,进而门诊医生递增药物剂量(图1)美国阿片处方药的销量在2000至2010年间成倍增长媒体报道过各种危害,药物依赖、服药过量导致意外身亡事件不断攀升4化其他长期毒副作用包括免疫抑制、内分泌失调、跌倒及骨折、急性心肌梗死、成瘾性、镇静嗜睡、认知受损。

关键词：阿片类药物疼痛患者慢性急性心肌梗死内分泌失调药物耐受媒体报道药物剂量

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FIRST-ORDER mEThODS FOR SOLVING ThE OPTImAL STATIC h∞-SYNThESIS PROBLEm

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Journal of Computational mathematics 2007年第6期25卷 672-689页

作者： El-Sayed m.E. mostafa Department of mathematics Faculty of Science Alexandria University Alexandria Egypt

In this paper, we consider the static output feedback （SOF） h∞-synthesis problem posed as a nonlinear semi-definite programming （NSDP） problem. Two numerical algorithms are developed to tackle the NSDP problem by solving the corresponding karush- kuhn-Tucker first-order necessary optimality conditions iteratively. Numerical results for various benchmark problems illustrating the performance of the proposed methods are given.

关键词： Static output feedback h∞-synthesis Semi-definite programming Nonlinear programming.

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Lifestyle intervention by group-based rehabilitation versus individual counseling in type 2 diabetes: 1-year follow-up of the Copenhagen type 2 diabetes rehabilitation project

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Journal of Diabetes mellitus 2012年第3期2卷 308-315页

作者： Eva Soelberg Vadstrup A.Frolich h.Perrild *** m.Roder Department of Endocrinology and Gastroenterology Bispebjerg University HospitalCopenhagenDenmark Department of Integrated healthcare Bispebjerg University HospitalCopenhagenDenmark health Care Center Oesterbro CopenhagenDenmark Department of Cardiology and Endocrinology Hillerød University HospitalHillerodDenmark

Background: Today most guidelines on the management of type 2 diabetes incorporate lifestyle intervention including patient education, physical activity and dietary modification. however, the content and organization of lifestyle intervention programs are still debatable. Aims: To compare the longer term effectiveness of a group-based rehabilitation program with an individual counseling program at improving glycemic control, cardiovascular risk factors and quality of life among type 2 diabetes patients. methods: We randomized 143 type 2 diabetes patients to either a 6-month group-based rehabilitation program, including patient education, supervised exercise, and diet intervention, or a 6-month individual counseling program. Follow-up time was 12 months after baseline. Outcome measures were glycated hemoglobin (hbA1c), cardiovascular risk factors, quality-of-life and self-rated health. Results: In the rehabilitation group, hbA1c decreased 0.2%-point (95% confidence interval [CI] = -0.4, -0.03), systolic blood pressure decreased 6 mmhg (95% CI = -9.3, -2.5), diastolic blood pressure decreased 4 mmhg (95% CI = -6.3, -2.4), weight decreased 2.2 kg (95% CI = -3.2, -1.3), and waist circumference decreased 2.0 cm (95% CI = -2.9, -1.1). In the individual group, hbA1c decreased 0.4% (95% CI = -0.6, -0.1), systolic blood pressure decreased 3 mmhg (95% CI = -6.3, -0.7), diastolic blood pressure decreased 3 mmhg (95% CI = -4.7, -0.7), weight decreased 1.6 kg (95% CI = -2.6, -.7]), and waist circumference decreased 1.6 cm (95% CI = -2.5, -0.6). Vitality, fatigue distress, physical functioning and cardiovascular distress improved over time (P he two groups combined. Repeated measurement analysis did not result in significant differences between the groups of any outcome. Conclusions: This study demonstrates that group-based rehabilitation in a primary healthcare center is a comparable alternative to individual counseling in an outpatient clinic. however, the resource

关键词： Rehabilitation Lifestyle Intervention Glycemic Control Quality of Life Cardiovascular Risk Factors

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Preventions and Controls on Congenital Transmissions of Zika: mathematical Analysis

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Applied mathematics 2017年第4期8卷 500-519页

作者： Nita h. Shah Zalak A. Patel Bijal m. Yeolekar Department of mathematics Gujarat University Ahmedabad Gujarat India L. D. College of Engineering Ahmedabad Gujarat India

Vector-borne diseases threat lives of millions of people in many countries of the world. Zika is one of the vector-borne diseases which initially spread by the bite of an infected Aedes species mosquito (Ae. aegypti and Ae. albopictus) and then it transmits vertically from a pregnant woman to her fetus or from an infected human to their sexual partners. The congenital transmission of Zika virus (ZIkV) results in new born with microcephaly and other neurological abnormalities. The control of infected mosquitos is the best efficient way to control spread of ZIkV. Spraying insecticide is the safest and easiest way to control mosquitos, but sometimes it is cost worthy for long period of spraying. Controlled prevention from the vector bites can also help to control disease spread. To control congenital transmission and sexual transmission of ZIkV, preventions should be taken to reduce/stop pregnancy rate and safe heterosexual transmission among adults. Also, there is no specific treatment available for Zika disease. Treatment is aimed at relieving symptoms with rest, fluids and medications. Controlled combinations of rest, fluids and medications will help to recover early. As costs are incorporated with spraying, preventions and treatment, our aim is to minimise the total cost associated by controlling spraying, preventions and treatment. To fulfil this purpose a mathematical model is developed with disease dynamics in nine compartments namely Susceptible human child, Susceptible human male, Susceptible human female, Infected human child, Infected human male, Infected human female, Recovered human, Susceptible vector and Infected vector including vertical transmission of Zika disease. Numerical simulations have been carried out to optimise controls, and basic reproduction number and stability are calculated.

关键词： Zika Vertical Transmission Dynamical System Control Stability

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Processing of Ceramic Based Nanocomposite Usingα-Al_2O_3 Powder and FeCl_2 Solution as Starting materials

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Journal of materials Science & Technology 2007年第6期23卷 837-842页

作者： mohamed m.EL-Sayed Seleman Department of materials and metallurgical Engineering Faculty of Petroleum and Mining EngineeringPost Code 43721SuezEgypt

Alumina-iron nanocomposite powders were prepared by a two-step process. In the first step, α-Al2O3-FeCl2 powder mixture was formed by mixing α-Al2O3 powders with FeCl2 solution followed by drying. In the second step, the FeCl2 in the dry power mixture was selectively reduced to iron particles. A reduction temperature of 750℃ for 15 min in dry h2 was chosen based on the thermodynamic calculations. The concentration of iron in FeCl2 solution was calculated to be 20 vol. pct in the final composite. Two techniques were used to produce composite bulk materials. The Al2O3 nanocomposite powders were divided to two batches. The first batch of the produced mixture was hot pressed at 1400℃ and 27 mPa for 30 min in a graphite die. To study the effect of oxygen on the Al2O3/Fe interface bonding and mechanical properties of the composite, the second batch was heat treated in air at 700℃ for 20 min to partially oxidize the iron particles before hot pressing. Characterization of the composites was undertaken by conventional density measurements, X-ray diffractometry （XRD）, scanning electron microscopy （SEm）, transmission electron microscopy （TEm） and electron probe micro analysis （EPmA）. The suggested processing route （mixing, reduction and hot pressing） produces ceramic-metal nanocomposite much tougher than the pure Al2O3. The fracture strength of the produced Al2O3/Fe nanocomposite is nearly twice that of the pure Al2O3. The presence of spinel phase, FeAl204, as thick layer around the Fe particles in the Al2O3 matrix has a detrimental effect on interfacial bonding between Fe and AI203 and the fracture properties of the composite.

关键词： Ferrous chloride Reduction Alumina-iron nanocomposite Spinel phase

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Generation of time-varying orbital angular momentum beams with space-time-coding digital metasurface

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Advanced Photonics 2023年第3期5卷 92-100页

作者： Jingxin Zhang Peixing Li Ray C.C.Cheung Alex m.h.Wong Jensen Li The hong kong University of Science and Technology Department of PhysicsHong KongChina City University of hong kong Department of Electrical EngineeringHong KongChina City University of hong kong State Key Laboratory of Terahertz and Millimeter WavesHong KongChina

The recently proposed extreme-ultraviolet beams with time-varying orbital angular momentum(OAm)realized by high-harmonic generation provide extraordinary tools for quantum excitation control and particle ***,such an approach is not easily scalable to other frequency *** design a space-time-coding digital metasurface operating in the microwave regime to experimentally generate time-varying OAm *** to the flexible programmability of the metasurface,a higher-order twist in the envelope wavefront structure of time-varying OAm beams can be further designed as an additional degree of *** time-varying OAm field patterns are dynamically mapped by developing a two-probe measurement *** approach in combining the programmability of space-time-coding digital metasurfaces and the two-probe measurement technique provides a versatile platform for generating and observing time-varying OAm and other spatiotemporal excitations in *** proposed time-varying OAm beams have application potentials in particle manipulation,time-division multiplexing,and information encryption.

关键词： time-varying orbital angular momentum digital-coding metasurfaces wavefront structure

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NONINVASIVE mEASUREmENT OF PERFUSION IN RABBIT VX2 TUmORS USING FLOW-SENSITIVE ALTERNATING INVERSING RECOVERY WITh AN EXTRA RADIOFREQUENCY PULSE

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波谱学杂志 2002年第1期19卷 100-100页

作者： R.h.WU D.F.kALLmES Z.J.LANG V.mAI h.B.RAO A.D.WILLIAmS k.m.kONG Shantou University medical College China University of Virginia USA University of Virginia USA Dalian medical University China Shantou University medical College China

Introduction:mR arterial spin-labeling technique is useful to measure tissue perfusion. The purpose of this study was to evaluate the feasibility of using a novel arterial spin-labeling technique to characterize regio... 详细信息

关键词： VX NONINVASIVE mEASUREmENT OF PERFUSION IN RABBIT VX2 TUmORS USING FLOW-SENSITIVE ALTERNATING INVERSING RECOVERY WITh AN EXTRA RADIOFREQUENCY PULSE

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LONG TERm SEDImENT YIELD AND mITIGATION IN A SmALL SOUThERN PIEDmONT WATERShED

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International Journal of Sediment Research 2000年第1期15卷 60-68页

作者： D.m. Endale(USDA-ARS, J. Phil Campbell Sr. Natural Resource Conservation Center, Watkinsville, GANote : This manucript of this paper was received in march 1999, Discussion open until march 2001.)h. h. SchombergJ. L. Steiner

Southern Piedmont lands suffer moderate to severe erosion when farmed under single-crop,conventional till systems consisting of moldboard plowing, disking or harrowing. This is primarily due to high soil erodibility, high energy spring-summer storms, low residue cover, and poor management thctors. A winter season with no crop often leaves soil unprotected from rainfall *** cropping systems that minimize tillage and leave a growing crop and crop residues on the surface both in summer and winter protect soil from erosive effects and sustain productivity. In this paper we present and discuss 26-years of soil loss, runoff and residue production data from a 2.71 ha catchment typical of small Southern Piedmont watersheds. The catchment was first managed in conventional tillage system of summer soybean (Glycine max (L.) merrill) and winter fallow from 1972 to 1974. It was then converted to conservation cropping systems of summer soybean, sorghum (Sorghuim bicolor (L.) moench), or cotton (Gossypium hirsutum (L.)) and winter barley (hordeum vulgare (L.)), wheat (Triticum aestivum (L.)), or clover (Trdolium incarnatum (L.)) which have continued to the present. Conservation cropping systems had immediate and residual effects in controlling erosion and runoff in both summer and winter. Destructive soil erosion, from high energy storms was significantly reduced. Residue production increased from about 2 mg ha-1 yr-1 under conventional tillage to 9.88 mg ha-1 yr-1 under conservation cropping systems over 20 years.

关键词： Soil erodibility Conservation cropping system Tillage system Erosive effect

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Does overshoot in leaf development of ponderosa pine in wet years leads to bark beetle outbreaks on fine-textured soils in drier years?

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Forest Ecosystems 2014年第4期1卷 214-226页

作者： Wendy Peterman Richard h Waring Conservation Biology Institute Department of Forest Ecosystems and Society Oregon State University

Background： Frequent outbreaks of insects and diseases have been recorded in the native forests of western North America during the last few decades, but the distribution of these outbreaks has been far from uniform. In some cases, recent climatic variations may explain some of this spatial variation along with the presence of expansive forests composed of dense, older trees. Forest managers and policy makers would benefit if areas especially prone to disturbance could be recognized so that mitigating actions could be taken. methods： We use two ponderosa pine-dominated sites in western montana, U.S.A. to apply a modeling approach that couples information acquired via remote sensing, soil surveys, and local weather stations to assess where bark beetle outbreaks might first occur and why. Although there was a general downward trend in precipitation for both sites over the period between 1998 and 2010 （slope =-1.3, R2 = 0.08）, interannual variability was high. Some years showed large increases followed by sharp decreases. Both sites had similar topography and fire histories, but bark beetle activity occurred earlier （circa 2000 to 2001） and more severely on one site than on the other. The initial canopy density of the two sites was also similar, with leaf area indices ranging between 1.7-2.0 m2. m-2. We wondered if the difference in bark beetle activity was related to soils that were higher in clay content at site I than at site II. To assess this possibility, we applied a process-based stand growth model （3-PG） to analyze the data and evaluate the hypotheses. Results： We found that when wet years were followed by drier years, the simulated annual wood production per unit of leaf area, a measure of tree vigor, dropped below a critical threshold on site I but not on site II. Conclusion： We concluded that the difference in vulnerability of the two stands to beetle outbreaks can be explained largely by differences in gross photosynthesis attributed to the fact that an equ

关键词： Does overshoot in leaf development of ponderosa pine in wet years leads to bark beetle outbreaks on fine-textured soils in drier years soil

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