Terrorism and the World Economy

Published as an article in: European Economic Review, 2008, vol. 52, issue 1, pages 1-27.

Methods of multiparameter inversion of seismic data using the acoustic and elastic born approximations

This thesis presents two different forms of the Born approximations for acoustic and elastic wavefields and discusses their application to the inversion of seismic data. The Born approximation is valid for small amplitude heterogeneities superimposed over a slowly varying background. The first method is related to frequency-wavenumber migration methods. It is shown to properly recover two independent acoustic parameters within the bandpass of the source time function of the experiment for contrasts of about 5 percent from data generated using an exact theory for flat interfaces. The independent determination of two parameters is shown to depend on the angle coverage of the medium. For surface data, the impedance profile is well recovered.

The second method explored is mathematically similar to iterative tomographic methods recently introduced in the geophysical literature. Its basis is an integral relation between the scattered wavefield and the medium parameters obtained after applying a far-field approximation to the first-order Born approximation. The Davidon-Fletcher-Powell algorithm is used since it converges faster than the steepest descent method. It consists essentially of successive backprojections of the recorded wavefield, with angular and propagation weighing coefficients for density and bulk modulus. After each backprojection, the forward problem is computed and the residual evaluated. Each backprojection is similar to a before-stack Kirchhoff migration and is therefore readily applicable to seismic data. Several examples of reconstruction for simple point scatterer models are performed. Recovery of the amplitudes of the anomalies are improved with successive iterations. Iterations also improve the sharpness of the images.

The elastic Born approximation, with the addition of a far-field approximation is shown to correspond physically to a sum of WKBJ-asymptotic scattered rays. Four types of scattered rays enter in the sum, corresponding to P-P, P-S, S-P and S-S pairs of incident-scattered rays. Incident rays propagate in the background medium, interacting only once with the scatterers. Scattered rays propagate as if in the background medium, with no interaction with the scatterers. An example of P-wave impedance inversion is performed on a VSP data set consisting of three offsets recorded in two wells.

Joule-Thomson coefficients of propane and n-butane

Experimental Joule-Thomson measurements were made on gaseous propane at temperatures from 100 to 280˚F and at pressures from 8 to 66 psia. Joule-Thomson measurements were also made on gaseous n-butane at temperatures from 100 to 280˚ and at pressures from 8 to 42 psia. For propane, the values of these measurements ranged from 0.07986˚F/psi at 280˚F and 8.01 psia to 0.19685˚F/psi at 100˚F and 66.15 psia. For n-butane, the values ranged from 0.11031˚F/psi at 280˚F and 9.36 psia to 0.30141˚F/psi at 100˚F and 41.02 psia. The experimental values have a maximum error of 1.5 percent.

For n-butane, the measurements of this study did not agree with previous Joule-Thomson measurements made in the Laboratory in 1935. The application of a thermal-transfer correction to the previous experimental measurements would cause the two sets of data to agree. Calculated values of the Joule-Thomson coefficient from other types of p-v-t data did agree with the present measurements for n-butane.

The apparatus used to measure the experimental Joule-Thomson coefficients had a radial-flow porous thimble and was operated at pressure changes between 2.3 and 8.6 psi. The major difference between this and other Joule-Thomson apparatus was its larger weight rates of flow (up to 6 pounds per hour) at atmospheric pressure. The flow rate was shown to have an appreciable effect on non-isenthalpic Joule-Thomson measurements.

Photographic materials on pages 79-81 are essential and will not reproduced clearly on Xerox copies. Photographic copies should be ordered.

Development of roll waves in open channels

This study is concerned with some of the properties of roll waves that develop naturally from a turbulent uniform flow in a wide rectangular channel on a constant steep slope . The wave properties considered were depth at the wave crest, depth at the wave trough, wave period, and wave velocity . The primary focus was on the mean values and standard deviations of the crest depths and wave periods at a given station and how these quantities varied with distance along the channel.

The wave properties were measured in a laboratory channel in which roll waves developed naturally from a uniform flow . The Froude number F (F = u_n/√gh_n, u_n = normal velocity , h_n = normal depth, g =acceleration of gravity) ranged from 3. 4 to 6. 0 for channel slopes S_o of . 05 and . 12 respectively . In the initial phase of their development the roll waves appeared as small amplitude waves with a continuous water surface profile . These small amplitude waves subsequently developed into large amplitude shock waves. Shock waves were found to overtake and combine with other shock waves with the result that the crest depth of the combined wave was larger than the crest depths before the overtake. Once roll waves began to develop, the mean value of the crest depths h_nmax increased with distance . Once the shock waves began to overtake, the mean wave period T_av increased approximately linearly with distance.

For a given Froude number and channel slope the observed quantities h^-_max/h_n , T' (T' = S_o T_av √g/h_n), and the standard deviations of h^-_max/h_n and T', could be expressed as unique functions of l/h_n (l = distance from beginning of channel) for the two-fold change in h_n occurring in the observed flows . A given value of h^-_max/h_n occurred at smaller values of l/h_n as the Froude number was increased. For a given value of h /hh^-_max/h_n the growth rate of δh^-_max/h^-_maxδl of the shock waves increased as the Froude number was increased.

A laboratory channel was also used to measure the wave properties of periodic permanent roll waves. For a given Froude number and channel slope the h^-_max/h_n vs. T' relation did not agree with a theory in which the weight of the shock front was neglected. After the theory was modified to include this weight, the observed values of h^-_max/h_n were within an average of 6.5 percent of the predicted values, and the maximum discrepancy was 13.5 percent.

For h^-_max/h_n sufficiently large (h^-_max/h_n > approximately 1.5) it was found that the h^-_max/h_n vs. T' relation for natural roll waves was practically identical to the h^-_max/h_n vs. T' relation for periodic permanent roll waves at the same Froude number and slope. As a result of this correspondence between periodic and natural roll waves, the growth rate δh^-_max/h^-_maxδl of shock waves was predicted to depend on the channel slope, and this slope dependence was observed in the experiments.

可见光波段双层浮雕型导模共振滤波器设计与分析

基于傅里叶模式理论分析了双层浮雕型导模共振光栅的共振效应,分别讨论了光栅的槽深、剩余厚度、周期以及填充系数对峰值反射率、带宽、旁带反射率的影响.数据计算表明,欠刻蚀情形的误差宽容度远远优于过刻蚀情形,两者在光栅槽深相对误差小于15%的范围内,都能保证共振峰的衍射效率高于99.5%,在相同的误差范围内,共振峰线宽的相对误差将分别达到7%和60%,因此厚度误差集中反映在对共振线宽的改变上.另外,光栅周期和填充系数的变化将明显改变共振峰中心波长和线宽.

New Products and Markets for Menhaden, Brevoortia spp.

Although menhaden, Brevoortia spp., represent 23.5 percent of United States commercial fishery landings, they represent only about 2.6 percent of the total landed value of fishery products. New food products and markets are needed to increase the economic value of the menhaden resource. This paper describes investigations of menhaden as a raw material for both traditional and new forms of food products. Canned menhaden is a logical food product, but the production of a menhaden surimi with good functionality has recently been demonstrated. The U.S. Food and Drug Administration has placed partially hydrogenated menhaden oil on the GRAS list of ingredients for food products, but a decision on the status of nutritionally beneficial refined menhaden oil is not yet available. Refined menhaden oil is currently the raw material for biomedical test materials being used in research approved by the National Institutes of Health to determine the health benefits of fish oils and omega-3 fatty acids. The test materials are being produced, with strict quality controls, at the NMFS Charleston Laboratory.

Simulated Economic Impact of TED Regulations on Selected Vessels in the Texas Shrimp Fishery

Shrimp fishermen trawling in the Gulf of Mexico and south Atlantic inadvertently capture and kill sea turtles which are classified as endangered species. Recent legislation requires the use of a Turtle Excluder Device(TED) which, when in place in the shrimp trawl, reduces sea turtle mortality. The impact of the TED on shrimp production is not known. This intermediate analysis of the TED regulations using an annual firm level simulation model indicated that the average Texas shrimp vessel had a low probability of being an economic success before regulations were enacted. An assumption that the TED regulations resulted in decreased production aggravated this condition and the change in Ending Net Worth and Net Present Value of Ending Net Worth before and after a TED was placed in the net was significant at the 5 percent level. However, the difference in the Internal Rate of Return for the TED and non-TED simulations was not significant unless the TED caused a substantial change in catch. This analysis did not allow for interactions between the fishermen in the shrimp industry, an assumption which could significantly alter the impact of TED use on the catch and earnings of the individual shrimp vessel.

U. S. Trade in Tuna for Canning, 1987

U.S. tuna fleet activity, canned tuna processing, ex-vessel, wholesale and retail prices and imports in 1987 are described and compared to their counterparts in previous years. Industry statistics gathered from government agencies and industry contacts are presented in 14 figures and 8 tables. In 1987, U.S. tuna fisheries delivered 253,136 short tons (tons) of tuna to U.S. canneries. Domestic deliveries of albacore (white-meat) tuna were 2,836 tons, down 20 percent from 1986 levels. Domestic deliveries of tropical (light-meat) tuna (bigeye, blackfin, bluefin, skipjack, and yellowfin) were 251,000 tons, up 12 percent. Contract prices for tuna delivered by U. S. vessels to U. S. canneries increased dramatically in 1987. Depending on the size of fish in the delivery, ex-vessel prices of white-meat tuna increased as much as 27 percent, and prices of light-meat tuna increased as much as 47 percent. U. S. cannery receipts of imported and domestically caught raw frozen tuna for canning totaled 532,704 tons in 1987, up 2 percent from 1986 levels. U.S. cannery receipts of white-meat tuna were 104,197 tons, down 10 percent from 1986. Imports made up 97 percent of the total cannery supply. Total 1987 U. S. cannery receipts of raw, frozen light meat tuna were 428,507 tons, up 5 percent from 1986 levels. Imports made up 41 percent of the total cannery supply. The 1987 U.S. pack of canned tuna was 33.6 million standard cases, up 3 percent from 1986. The pack of white-meat tuna was 7.2 million standard cases, down 11 percent from 1986; the pack of light-meat tuna was 26.4 million standard cases, up 7 percent. U. S. imports of canned tuna in 1987 were 10.8 million standard cases, down 11 percent from 1986 levels, the first time in recent years that imports have declined. Per capita consumption of canned tuna in the United States was 3.5 pounds in 1987, down slightly from 1986. The retail composite price was $2.26 per pound, unchanged from 1986.

Isolatin [sic] the bacteria produced biactive [sic] metabolits [sic] cytotoxic compound in order to prduction [sic] anticancer substance in the coral regin [sic] the Persian Gulf (Larak Island)

In the present investigation the marine bacteria isolated from corals, sponges sea water and sediments of coral regions in the larak Island located in the Persian Gulf and were examined for ability to produce cytotoxic metabolits in order to use as an anticancer compounds. Cytotoxic effect were isolated bacteria from different samples and were examined by Artemia Cytotoxic Bioassay test, in which 4.5 percent of sea waters, 12 percent of sediments and 28 percent of marine invertebrat showed cytotoxic activity, using Brine Shrimp Bioassay test. Streptomyces S-2004 isolated from soft coral specified as Sinularia erecta had LC50=0.5mg/m1 in Brine Shrimp Bioaassay test. The streptomyces S-2004 produced cytotoxic metabolits in low nutrient condition and sea water medium after 7 days on 250 rpm shaken in vitro condition. The extract partially were semipurified. Then ethyl acetate extraction from aceton extracted of bacterial plate had cytotoxic effect (LC50=4.19ktg/m1) in Human epidermoid carcinoma of mouth cells (KB) by using neutral red assay. Morphological effects of this extract on KB cells showed turgescence, cellular blebs and apoptosis which was a proof for anticancer compounds of the extract. It is seems that streptomyces S-2004 is a new strain and could be introduced as a talented bacteria, which produced cytotoxic metabolits.

西藏红拉雪山自然保护区黑白仰鼻猴 Rhinopithecus bieti 的生态与行为研究，中国及其邻近地区兽类动物地理区划数量分析

从 2002 年11 月至2005 年4 月，在西藏红拉雪山自然保护区（98°20' ~ 98°59'E，28°48' ~ 29°40'N）对小昌都黑白仰鼻猴（Rhinopithecus bieti）群（98°35'00" ~ 98°40'00"E，29°14'24" ~ 29°16'42"N）（210 只左右）的生境及其利用形式、食 性、活动时间分配、过夜树及过夜地选择、雄－婴照料和繁殖季节作了重点研究， 并对保护区内的猴群分布、种群数量、保护状态以及潜在的威胁因素等作了一般 性的考查研究。 红拉雪山自然保护区存在3 个黑白仰鼻猴群，数量至少有300 只。从北到南 分别是执娜群、小昌都群和米拉卡群，其中执娜群（29°22'，98°28'），是黑白仰 鼻猴最北分布群。猴群栖息范围中，人类的经济活动频繁。由于活动范围位于或 接近藏传佛教的神山，小昌都和执娜猴群保护最好，这两群之间存在生境走廊。 米拉卡猴群保护状态较差，主要是偷猎现象还没有杜绝。对过去20 年的农牧业 统计资料及藏族风俗习惯和民族传统综合分析发现：在红拉雪山自然保护区，尽 管人类经济活动频繁，但猴群与人类和谐共存是可能的。 小昌都猴群全年白天用49％的时间取食，20％的时间移动，18％的时间休 息，13％的时间作其他的活动。在6-8 月，猴群日间表现出明显的三个取食高峰， 两个休息高峰。在11-1 月，猴群有两个取食高峰，一个休息高峰，或者休息高 峰根本不明显（12 月）。尽管环境温度和食物组成等也会影响时间预算，但造成 这种现象的主要原因可能是白天长度的季节性变化。 小昌都猴群年家域为21.25 km2，且主要在3800 – 4250 米的针叶林中活动。 食物好的季节，猴群日移动距离长，日活动范围大；食物差的季节，则相反。秋 －冬季（10-12 月）由于取食川滇高山栎（Quercus aquifolioides），活动的海拔高 度高于其它季节；冬季（1-4 月）活动范围最低。猴群并不避免在人类间伐过的 次生针叶林中活动。小生境的使用强度与在此生境中过夜的次数有关。 小昌都猴群的食物以松萝为主。全年的食物组成：用单筒望远镜观察，松萝 82.1％，芽和叶12.1%，花、果实或种子占1.1%，无脊椎动物占0.6%，树皮、 树根、树胶，草等占4.2%；接近猴群用肉眼或双筒望远镜观察，松萝50.8％， 芽和叶28.5%，花、果实或种子占7.1%，无脊椎动物占6.5%，树皮、树根、树胶，草等占7.1%。根据动物在不同林层分布百分比整合后得到接近真实的食物 构成：松萝75.4％，芽和叶15.7%，花、果实或种子占2.9%，无脊椎动物占2.4%， 树皮、树根、树胶，草等占3.9%。猴群在夏季（6-8 月）会下地翻开小石块，取 食无脊椎动物。冬季（1-4 月）会取食至少6 种树皮和2-3 种干草。 基于避免捕食、安全、舒适、体温调节的考虑，小昌都猴群选择高大、底枝 高、底枝长以及层数多的树过夜，并在背风、阳坡和海拔低的过夜地过夜。在过 夜地的选择中，存在着阳坡和海拔高度的权衡决策。 小昌都猴群个体不同林层的分布：77.5％在树上，6.0％在灌丛，16.5％在地 上。成年雄猴和青年猴倾向于在地上活动。在地上活动时又倾向于移动，休息和 其他活动少。获得高质量的食物和避免被捕食是出现这种格局的原因。 在小昌都猴群中，婴猴受到雄猴照料时间百分比（percent time of infant care, PTIC）为17.2±3.3，其中身体接触（BC）、接近（IP）和监护（G）照料的时 间百分比分别为0.6±0.5、5.8±1.2 和10.8±3.8。G 照料的最低值和最高值分别 在8 月和3 月。雌猴总PTIC 为69.3±6.9，其中BC、IP 和G 的时间分别为42.0 ±8.6、21.6±5.3 和5.7±3.8。最低BC 和最高G 照料同时出现在3 月。对雄猴， （1）总PTIC 在能量压力高的季节明显高于能量压力低的季节；（2）G 照料PTIC 在能量压力高的季节也要比能量压力低的季节高；（3）BC 和IP 照料在两个季节 之间没有区别。对于雌猴，（1）总PTIC 在高能量压力季节要比低能量压力季节 低；（2）G 照料在高能量压力季节要比低能量压力季节高，而BC 照料在高能量 压力季节要比低能量压力季节低；（3）IP 照料在两个季节之间没有区别。这种 高强度的雄婴照料，特别是托儿所的照料方式，是由这种环境下过高的能量压力 所引起的。 小昌都群为严格季节性出生且出生季节在2 月初到3 月中旬之间，时间跨度 45 天，属脉冲型。这种格局是光周期、温度、食物等环境因子综合调控的结果。 综合以上结果我们认为小昌都群的行为和生态特点，除具备疣猴一般特点 外，还具有地点特殊性，是自然环境如光照、温度、食物供给季节变化和生物环 境如捕食压和人类活动相互作用的结果，或者可以看成是能量摄入和损耗之间以 及它们和安全之间的权衡结果，体现了猴群对极端环境的适应。

Effect of Nd on the microstructure, mechanical properties and corrosion behavior of die-cast Mg-4Al-based alloy

Die-cast Mg-4Al-0.4Mn-xNd(x = 0, 1, 2, 4 and 6 wt.%) magnesium alloys were prepared successfully and influences of Nd on the microstructure, mechanical properties and corrosion behavior of the Mg-4Al-0.4Mn alloy have been investigated. The results showed that with the addition of Nd binary Al2Nd phase and Al11Nd3 phase. which mainly aggregated along the grain boundaries, were formed, and the relative ratio of above two phases was in correlation with the Nd content in the alloy. Meanwhile, the grain sizes were greatly reduced with the increasing Nd content. It was found that due to the addition of Nd both the tensile properties and corrosion resistance were improved substantially.

藏东及滇东南新生代钾质岩浆作用及其深部制约

The dissertation focuses on the petrology, geochemistry of the volcanic rocks in east Tibet and southeast Yunnan. It lucubrates the Magmatic process, forming mechanism and the possible tectonic settings of the volcanic rocks. The volcanic rocks of Nangqen basin in east Tibet, Qinghai province are mainly Cenozoic intermediate-acid shoshonites. The rocks are LREE enriched and the LREE/HREE = 3～34; (La/Yb)_N = 18.17-53.59, and ΣREE 222～1260μg/g. There are no Eu anomaly, and Nb, Ta, Zr, Hf, Ti are markedly depleted. The isotopic composition is ~(87)Sr/~(86)Sr = 0.70497～0.70614, ~(206)Pb/~(204)Pb = 18.622～18.974, ~(208)Pb/~(204)Pb = 38.431～38.996, ~(207)Pb/~(204)Pb = 15.511～15.613, respectively. K-Ar age of the whole rocks and the single mineral are between 32.0-36.5Ma. Based on the trace elements and isotopic elements, we get the conclusion that the partial melting is one of the dominated forming mechanisms for the volcanic rocks in Naneqen basin. The magma did not experience the crustal contamination en route to the surface; however, the complex mixture took place in the upper mantle before the melt was formed. There are at least two kinds of mixed sources that can be identified. The basalt in southeast Yunnan province is studied. They are distributed in Maguan, Tongguan, and Pingbian County, which is located on the both sides of the Red River belt, and the ultrabasic xenolith are cursory introduced. The volcanic rocks belongs to the alkali series, which can be subdivided into trachybasalt and basanite(Ol normal molecule >5). The volcanic rocks are characteristics by high Ti and low Mg#. According to the magma calculation model, the original rocks of the basalt in southeast Yunnan province are Spinel Lherzolite in Tongguan, Garnet Lherzolite in Pingbian and Maguan, while Togguan undergoes 2-5 percent and percent of partial melting, whereas volcanism in Maguan and Pingbian was so complex to calculate. The fractional crystallization took place during the magma evoltion in southeast Yunnan. The basalt is enriched in LREE with LREE/HREE=9.23-20.19. All of the trace elements display weak Nb, Ta peak, and the depletion of Zr, Hf and Ti in Maguan and pingbian represent the presence of Garnet in the source. The composition of the isotope ratio are ~(87)Sr/~(86)Sr = 0.70333-0.70427, ~(143)Nd/~(144)Nd = 0.512769-0.512940, ~(206)Pb/~(204)Pb = 18.104-18.424, ~(207)Pb/~(204)Pb = 15.483 -15.527; ~(208)Pb/~(204)Pb = 37.938-38.560, respectively, which shows the characteristics of the HIMU type OIB. The volcanic rocks of the southwest Yunnan are derived from the enriched, OIB type mantle sources by synthesizing all the data from trace and isotope elements. It is similar to that of the volcanic rocks in Hawaii, a typical kind of the mixtures of the recycled oceanic crust plume and depleted asthenosphere. To sum up, the volcanic rocks in southeast Yunnan are formed by the intraplate hotpot volcanism.

Using a brief questionnaire to assess the overall perception of basketball spectators

Purpose – The purpose of this paper is twofold. The first aim is to obtain a valid and reliable instrument for the holistic analysis of sporting events, and the second is to test a causal model in which future intentions depend on spectators’ perceptions of quality, satisfaction, and value of these events. Design/methodology/approach – A total of 493 spectators of a professional basketball team in the Spanish ACB league responded to a survey to measure the overall performance of the sporting event service. Exploratory factor analysis and further confirmatory factor analysis using structural equation models provides the methodology for testing the reliability and validity of the instrument. Findings – The scales have adequate reliability and validity indices. The path model explains 35.8 percent of the variance in future intentions, 54.0 percent in perceived value, and 49.5 percent in spectators’ satisfaction. Quality proves a better predictor of perceived value than satisfaction. Both perceived value and satisfaction have a similar weight in predicting spectators’ future intentions. The data indicate that quality has an effect on spectators’ future intentions, by altering their perceptions of value and satisfaction. Research limitations/implications – The research findings are somewhat limited, due to the sample consisting entirely of spectators of a single team in the Spanish ACB league. Practical implications – Managers can use these findings to develop loyalty strategies by creating service value and increasing spectators’ satisfaction through quality improvements. Originality/value – This study contributes to the literature on service quality by providing an overall measure to assess service in professional sporting events in a Latin-American context.

A unified framework for measuring preferences for schools and neighborhoods

This paper develops a framework for estimating household preferences for school and neighborhood attributes in the presence of sorting. It embeds a boundary discontinuity design in a heterogeneous residential choice model, addressing the endogeneity of school and neighborhood characteristics. The model is estimated using restricted-access Census data from a large metropolitan area, yielding a number of new results. First, households are willing to pay less than 1 percent more in house prices - substantially lower than previous estimates - when the average performance of the local school increases by 5 percent. Second, much of the apparent willingness to pay for more educated and wealthier neighbors is explained by the correlation of these sociodemographic measures with unobserved neighborhood quality. Third, neighborhood race is not capitalized directly into housing prices; instead, the negative correlation of neighborhood percent black and housing prices is due entirely to the fact that blacks live in unobservably lower-quality neighborhoods. Finally, there is considerable heterogeneity in preferences for schools and neighbors, with households preferring to self-segregate on the basis of both race and education. © 2007 by The University of Chicago. All rights reserved.

Cost-effectiveness of electricity energy efficiency programs

We analyze the cost-effectiveness of electric utility ratepayer-funded programs to promote demand-side management (DSM) and energy efficiency (EE) investments. We specify a model that relates electricity demand to previous EE DSM spending, energy prices, income, weather, and other demand factors. In contrast to previous studies, we allow EE DSM spending to have a potential longterm demand effect and explicitly address possible endogeneity in spending. We find that current period EE DSM expenditures reduce electricity demand and that this effect persists for a number of years. Our findings suggest that ratepayer funded DSM expenditures between 1992 and 2006 produced a central estimate of 0.9 percent savings in electricity consumption over that time period and a 1.8 percent savings over all years. These energy savings came at an expected average cost to utilities of roughly 5 cents per kWh saved when future savings are discounted at a 5 percent rate. Copyright © 2012 by the IAEE. All rights reserved.