bluuebunny/crossref_metadata_2025 huggingface dataset:
Actin‐based centripetal flow: Phosphatase inhibition by calyculin‐A alters flow pattern, actin organization, and actomyosin distribution
Authors: Henson John H. , Kolnik Sarah E. , Fried Christopher A. , Nazarian Ronniel , McGreevy Jeanine , Schulberg Katrina L. , Detweiler Megan , Trabosh Valerie A.
Published: October 2003

Previous studies have suggested that the actin‐based centripetal flow process in sea urchin coelomocytes is the result of a two‐part mechanism, actin polymerization at the cell edge coupled with actomyosin contraction at the cell center. In the present study, we have extended the testing of this two‐part model by attempting to stimulate actomyosin contraction via treatment of coelomocytes with the phosphatase inhibitor Calyculin A (CalyA). The effects of this drug were studied using digitally‐enhanced video microscopy of living cells combined with immunofluorescent localization and scanning electron microscopy. Under the influence of CalyA, the coelomocyte actin cytoskeleton undergoes a radical reorganization from a dense network to one displaying an array of tangential arcs and radial rivulets in which actin and the Arp2/3 complex concentrate. In addition, the structure and dynamics of the cell center are transformed due to the accumulation of actin and membrane in this region and the constriction of the central actomyosin ring. Physiological evidence of an increase in actomyosin‐based contractility following CalyA treatment was demonstrated in experiments in which cells generated tears in their cell centers in response to the drug. Western blotting and immunofluorescent localization with antibodies against the phosphorylated form of the myosin regulatory light chain (MRLC) suggested that the demonstrated constriction of actomyosin distribution was the result of CalyA‐induced phosphorylation of MRLC. Overall, the results suggest that there is significant cross talk between the two underlying mechanisms of actin polymerization and actomyosin contraction, and indicate that changes in actomyosin tension may be translated into alterations in the structural organization of the actin cytoskeleton. Cell Motil. Cytoskeleton 56:252–266, 2003. © 2003 Wiley‐Liss, Inc.
Characteristics of primary care physicians and their practices associated with mammography rates for older women
Authors: Van Harrison R. , Janz Nancy K. , Wolfe Robert A. , Tedeschi Philip J. , Stross Jeoffrey K. , Huang Xuelin , McMahon Laurence F.
Published: October 2003

BACKGROUND

Mammography screening rates are below national recommendations for older women. Understanding the relation between the characteristics of primary care physicians (PCPs) and mammography rates for older women can help to target screening improvement efforts.

METHODS

Subjects were 2527 PCPs practicing in Michigan between 1997 and 1998. A cross‐sectional design used Medicare data to identify women age 68 years or older in 1998 whom PCPs treated in 1997–1998 and to determine whether these women had a mammogram between 1996 and1998. Eligible women were Medicare beneficiaries age 65 years or older by 1996, residing in Michigan from 1996 to 1998, without specified comorbidities likely to affect decisions regarding mammography. Correlations and multiple regressions examined the relation between this score and characteristics of both PCPs and their practice populations of older women.

RESULTS

Mammography rates across physicians' practices ranged from 3–100% (mean = 59%, standard deviation = 17%). Five predictors accounted for 55% of the variance in mammography rates across practices. Higher mammography rates were found to be independently related to physicians who have: a lower mean age for female Medicare patients, a higher mean number of physicians billing for patients' care, a lower mean number of inpatient admissions, obstetrics/gynecology practices, and a higher mean education level in patient's zip code (beta weights ≥ 0.25, P < 0.0001).

CONCLUSIONS

PCPs vary substantially with regard to mammography rates for older women. Mammography rates vary more with the population of patients in physicians' practices than with commonly measured personal characteristics of physicians. Mammography rates should be adjusted for patient population to target individual PCPs with low mammography rates for interventions. Cancer 2003. © 2003 American Cancer Society.
Opposing effect of angiopoietin‐1 on VEGF‐mediated disruption of endothelial cell–cell interactions requires activation of PKCβ
Authors: Wang Yihong , Pampou Sergey , Fujikawa Koshi , Varticovski Lyuba
Published: October 2003

Angiopoietin‐1 (Ang1) and vascular endothelial growth factor (VEGF) cooperate in migration and survival of endothelial cells by activation of phosphatidylinositol‐3 (PI‐3) kinase and mitogen activating protein (MAP) kinase pathways. However, Ang1 opposes the effect of VEGF on vascular permeability. We found that Ang1 also blocks VEGF‐mediated diffusion of fluoresin isothiocyanate (FITC)‐labeled albumin across an endothelial cell monolayer. VEGF‐mediated vascular permeability has been attributed, in part, to activation of phospholipase A2 and subsequent formation of platelet activating factor. However, Ang1 had no effect on VEGF‐induced activation of phospholipase A2 or the release of arachidonic acid. VEGF‐mediated permeability was associated with disruption of endothelial cell junctional complexes, dissociation of β‐catenin from VE‐cadherin, and accumulation of β‐catenin in the cytosol. In contrast, Ang1 enhanced the interaction of β‐catenin with VE‐cadherin and impaired VEGF‐mediated dissociation of this complex. Ang1 also blocked VEGF‐induced translocation of protein kinase C (PKC) and β2 to the membrane, but had no effect on activation of PKCα. In addition, staurosporine and a PKCβ inhibitor, LY379196, blocked VEGF‐mediated dissociation of β‐catenin from VE‐cadherin, diffusion of albumin across the endothelial cell monolayer, and translocation of PKCβ isoforms. These data indicate that VEGF‐mediated disruption of endothelial cell–cell interactions requires activation of PKCβ isoforms and that this pathway is blocked by Ang1. J. Cell. Physiol. 198: 53–61, 2004. © 2003 Wiley‐Liss, Inc.
Linking phenomena with competing underlying models: A software tool for introducing students to the particulate model of matter
Authors: Snir Joseph , Smith Carol L. , Raz Gila
Published: October 2003

Helping students understand the general nature of scientific models is increasingly regarded as an important goal of the middle and high school science curriculum (e.g., J. K. Gilbert & C. Boutler, 1998. International Handbook of Science Education; Kluwer, London; A. G. Harrison & D. F. Treagust, 2000. Science Education, 352–381). In addition, beginning in middle school, students are introduced to one of the most central models in modern science—the particulate model of matter. Thus, teaching students about this model is an ideal opportunity to help students develop an understanding of the nature of models in the context of learning a central scientific concept—the discontinuity of matter. In this article, we present a software tool that was designed for this purpose. The software engages students with investigating and evaluating competing models of matter in order to help them see the particulate model as a plausible model that can explain a wide range of facts about diverse phenomena. The first and second parts of the paper describe the scientific content of the particulate model and the main ideas about scientific models that we would like to teach, as well as the educational challenges of teaching these ideas to middle school students. The third part describes the structure of the software and the three phenomena we chose to have students explore. These are all phenomena that should be puzzling to students if they assume that matter is continuous, but that can be easily explained if they assume that matter consists of discrete particles. The paper concludes with a description of two studies evaluating the effectiveness of the software in promoting students' understanding of models in general and the particulate model of matter in particular. We found that middle schoolers can engage with fundamental ideas about the nature of models, and that engaging them with these ideas helps them internalize the assumptions of the particulate model of matter. This happened especially for students who had developed relevant macroscopic conceptions of matter based upon quantified and interrelated conceptions of volume, weight, and density. © 2003 Wiley Periodicals, Inc. Sci Ed 87:794–830, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/sce.10069
Some recent contributions of FTIR difference spectroscopy to the study of cytochrome oxidase1
Authors: Gennis Robert B
Published: October 2003

In this minireview, some of the new findings using infrared spectroscopy to study cytochrome oxidase will be reviewed, with an emphasis on those studies involving our laboratory.
Seven evolutionarily conserved human rhodopsin G protein‐coupled receptors lacking close relatives
Authors: Fredriksson Robert , Höglund Pär J , Gloriam David E.I , Lagerström Malin C , Schiöth Helgi B
Published: October 2003

We report seven new members of the superfamily of human G protein‐coupled receptors (GPCRs) found by searches in the human genome databases, termed GPR100, GPR119, GPR120, GPR135, GPR136, GPR141, and GPR142. We also report 16 orthologues of these receptors in mouse, rat, fugu (pufferfish) and zebrafish. Phylogenetic analysis shows that these are additional members of the family of rhodopsin‐type GPCRs. GPR100 shows similarity with the orphan receptor SALPR. Remarkably, the other receptors do not have any close relative among other known human rhodopsin‐like GPCRs. Most of these orphan receptors are highly conserved through several vertebrate species and are present in single copies. Analysis of expressed sequence tag (EST) sequences indicated individual expression patterns, such as for GPR135, which was found in a wide variety of tissues including eye, brain, cervix, stomach and testis. Several ESTs for GPR141 were found in marrow and cancer cells, while the other receptors seem to have more restricted expression patterns.
Emerging Sources of Labor on the Internet: The Case of America Online Volunteers
Authors: Postigo Hector
Published: October 2003

In 1995 AOL announced that it would be converting its pricing plan from an hourly rate that ranged from $3 to $6 an hour to a flat monthly rate of $15.95. The increase in member subscription was expected to be significant, and a wave of concern swept through the large remote-staff volunteer population, whose duties included monitoring electronic bulletin boards, hosting chat-rooms, enforcing the Terms of Service agreement (TOS), guiding AOL users through the online community, and even creating content using the AOL's own program, RAINMAN (Remote Automated Information Manager), the text scripting language and the publishing tool that allows remote staffers to update and change content on AOL. Chief among remote-staff volunteer's concerns was the initiative to convert many of the volunteer accounts from overhead accounts, which had access to tools and privileges that made remote-staff volunteers' duties on par with in-house employees, to unbilled or discounted accounts. In a meeting meant to address the emerging concerns of remote-staff volunteers held over electronic chat, Bob Marean, a representative for AOL, confronted over 450 remote-staff volunteers.
The Raincoats: breaking down punk rock's masculinities
Authors: O'Meara Caroline
Published: October 2003

The Raincoats were one of a handful of British, all-female punk bands successful enough to release records and tour internationally. Since the late 1970s, critics intrigued by the idea that music can enact gender, have heard their music as somehow embodying femininity. I explore the discursive origins of the Raincoats music as ‘feminine music’ before analysing their music to determine the specific nature of their work as female punk musicians. The Raincoats took advantage of punk's ideology of amateurism to shatter traditional (read: masculine) subjectivity in rock music. Analysing their music reveals the ways in which their music triggers listening that encourages an understanding of their music as feminine.
A critical reassessment of the reception of early jazz in Britain
Authors: Parsonage Catherine
Published: October 2003

The Original Dixieland Jazz Band's visit in 1919–1920 has been well documented as the beginning of jazz in Britain. This article illuminates a more complex evolution of the image and presence of jazz in Britain through consideration of the cultural and musical antecedents of the genre, including minstrel shows and black musical theatre, within the context of musical life in Britain in the late nineteenth to early twentieth centuries. The processes through which this evolution took place are considered with reference to the ways in which jazz was introduced to Britain through imported revue shows and sheet music.

It is an extremely significant but often neglected fact that another group of American musicians, Will Marion Cook's Southern Syncopated Orchestra, also came to Britain in 1919. Remarkably, extensive comparisons of the respective performances and reception of the ODJB and the SSO have not been made in the available literature on jazz. Examination of the situation of one white and one black group of American musicians performing contemporaneously in London is extremely informative, as it evidences the continuing influence of the antecedents of jazz and the importance of both groups in shaping perceptions of jazz in Britain.
Musicology, ethnomusicology and popular music studies:
two conferences in Japan in 2002
Authors: Mitsui Tôru
Published: October 2003

The Musicological Society of Japan celebrated its fiftieth anniversary by holding an
international congress on 2–4 November 2002 in Shizuoka, a city which is not far
from Tokyo, whose skyline is backed by the imposing Mount Fuji. 470 people were
registered as participants, out of whom about 100 were from abroad. The conference
coincided with the International Convention of Street Performance in the same city.
On the planar stability of rigid-link binary walking robots
Authors: Zhou Yu
Published: October 2003

A binary walking robot moves as a result of bi-state actuator
transitions. Because of the bi-state nature of binary joints, many research results about continuous walking robots cannot be applied to binary walking robots directly. In this paper, a new and simple model of rigid-link binary walking robot is proposed, around which related concepts are introduced, and formulas are derived. Based on this model, general characteristics and limitations of periodic gaits are discussed, and the stability qualities of several straight-line walking periodic gaits are studied in both pitch-greater-than-stroke and stroke-greater-than-pitch cases. Valuable results are obtained from the analysis, which should be followed in the design of rigid-link binary walking robots.
Force strategies for on-line obstacle avoidance for redundant manipulators
Authors: Zlajpah Leon , Nemec Bojan
Published: October 2003

The paper deals with on-line obstacle avoidance in an unstructured environment based on the force strategy. The obstacle avoidance is considered as a control problem. We discuss three approaches regarding the sensors used to detect the obstacles. First we investigate how obstacles can be avoided without using any sensors to detect them. To solve the problem we make use of a very basic principle: an action causes a reaction. For backdrivable manipulators we propose a controller which ensures stiff behaviour in the task space and compliant behaviour in the null space. Using such control the
tracking capabilities in the task space can be preserved and the redundant degrees of freedom are used to avoid the obstacle after the collision. The tactile sensors are proposed to be used as the alternative for stiff systems. A tactile sensor detects an obstacle and the controller generates the avoiding motion. Last, we present a virtual forces approach which can be applied to the systems with proximity sensors. The objective is to assign each point on the body of the manipulator, which is close to the obstacle force component in a direction that is away from the obstacle. The proposed formulation avoids the problem of singular configurations and is very suitable when many obstacles are present in the neighbourhood of
the manipulator. The computational efficiency of the proposed algorithms allows real-time application in a unstructured or time-varying environment. The efficiency of the proposed control algorithms is illustrated by simulations of highly redundant planar manipulators and by experiments on a four link planar manipulator.
Design and control of a three degree of freedom pneumatic
physiotherapy robot
Authors: Richardson R. , Brown M. , Bhakta B. , Levesley M.C.
Published: October 2003

Stroke is a common condition resulting in 30,000 people per annum left with significant disability. In patients with severe arm paresis after stroke, functional recovery in the affected arm is poor. Inadequate intensity of treatment is cited as one factor accounting for the lack of arm recovery found in some studies. Given that physical therapy resource is limited, strategies to enhance the physiotherapists' efforts are needed. One approach is to use robotic techniques to augment movement therapy.

A three degree-of-freedom pneumatic robot has been developed to apply physiotherapy to
the upper limb. The robot has been designed with a workspace encompassing the reach-retrieve range of the average male. Control experiments have applied force and then position only controllers to the pneumatic robot. These controllers are combined to form a
position-based impedance control strategy on all degrees of freedom of the robot. The impedance controller performance was found to be dependent upon the specified impedance parameters. Initial experiments attaching the device to human subjects have indicated great potential for the device.
Collective Ownership or Cadres' Ownership? The Non-agricultural Use of Farmland in
China
Authors: Cai Yongshun
Published: October 2003

In China during the reform period, the multitude of conflicts between the state or its agents and peasants has become a serious concern for the Chinese government. A fundamental reason for these conflicts is the fact that peasants' basic economic or political interests have been threatened or ignored. Using the case of non-agricultural use of farmland, this study seeks to explain why the peasants' lack of resistive power appears institutionalized in China. The use of rural land often gives rise to conflicts because peasants are usually under-compensated for their land. Facing the encroachment of their interests, peasants may take ex ante preventive action and ex post measures. While ex ante action is more effective, it is not always feasible because it needs the organizing of village cadres. Hence, peasants are weak because usually action can only be taken ex post, which, more often than not, is ineffective because of the political arrangements through which the state, peasants and cadres interact.
China and the World Trade Organization: A Legal Perspective. By Kong Qingjiang. [Singapore: World Scientific Publishing, 2002. xiv+350 pp. ISBN 981-238-039-6.]
Authors: Potter Pitman B.
Published: October 2003

China's accession to the World Trade Organization (WTO) has generated an avalanche of books and articles offering a variety of academic, policy and legal perspectives. Kong Qingjiang's contribution is primarily an explanation of the perspectives of the Chinese government on WTO accession, and focuses on three broad themes: the background to China's WTO accession, dispute resolution, and trade compliance.
A County of Culture: Twentieth Century China Seen from the Village Schools of Zouping, Shandong. By Stig ThØgersen. [Ann Arbor: University of Michigan Press, 2002. 310 pp. £37.50. ISBN 0-472-11283-X.]
Authors: Murphy Rachel
Published: October 2003

This empirically rich and analytically engaging book draws on archives and oral history in Zouping county, Shandong province, and devotes each chapter to a distinctive period in the building of China's modern educational institutions. The study reveals how macro-level historical shifts interact with educational reforms to impact on the lives of rural individuals, and how their responses shape community-level policy formulation and implementation. Educational reforms therefore form the basis for a wider study of cultural, socio-economic and political processes in 20th-century China.
Place and Spirit in Taiwan: Tudi Gong in the Stories, Strategies and Memories of Everyday Life. By Allessandro Dell'Orto. [London and New York: RoutledgeCurzon, 2002. xix+300 pp. $55.00. ISBN 0-7007-1568-1.]
Authors: Katz Paul R.
Published: October 2003

In this ground-breaking study of the cult of Tudi Gong (generally referred to in English as the Earth God or the God of the Soil), Allessandro Dell'Orto sheds new light on the significance of one of the most popular deities in the Chinese pantheon, while also making an important contribution to the ongoing discussion of methodological issues in the field of anthropology.
Effects of the acanthocephalan parasite Echinorhynchus truttae on the feeding ecology of Gammarus pulex (Crustacea: Amphipoda)
Authors: Fielding Nina J. , MacNeil Calum , Dick Jaimie T. A. , Elwood Robert W. , Riddell Gillian E. , Dunn Alison M.
Published: October 2003

The amphipod Gammarus pulex is an intermediate host to the acanthocephalan fish parasite Echinorhynchus truttae. Gammarus pulex has a wide trophic repertoire, feeding as a herbivore, detritivore and predator. In this study an examination was made of the effects of E. truttae parasitism on components of the G. pulex diet: stream‐conditioned leaves, dead chironomids and live juvenile isopods Asellus aquaticus. Over 21 days, parasitism had no effect on daily feeding rates or wet weights of G. pulex fed on leaves or chironomids. Parasitism had a significant effect on the number of A. aquaticus killed by G. pulex, with parasitized individuals killing significantly fewer than their unparasitized counterparts. In addition, unparasitized amphipods killed all size classes of A. aquaticus indiscriminately, whereas parasitized animals tended to kill the smaller size classes. The impacts of the parasitism of G. pulex throughout the wider freshwater community are discussed.
Feeding habitat of giant pandas (Ailuropoda melanoleuca): why do they prefer bamboo patch edges?
Authors: Yu Guangzhi , Jiang Zhigang , Zhao Zhilong , Wang Bingfeng , Wang Yong
Published: October 2003

The factors that affect the selection of feeding sites by giant pandas Ailuropoda melanoleuca in the Longxi‐Hongkou Nature Reserve were explored in winter from 2000 to 2002, by using strip transects. It was reported in the literature that giant pandas prefer to forage on the edges of bamboo patches because these edges offer them more food than the interiors. The number of feeding sites and the corresponding vegetation indices (including the basal diameter of bamboo stem, height and density of bamboo or bamboo shoot; density and canopy density of trees) were compared close to and far away from the edges of bamboo patches to detect the patterns of feeding habitat selection by giant pandas. Giant pandas preferred to forage at the sites near edges rather than in the interiors of bamboo patches. Such a tendency was independent of bamboo species and individual pandas. By comparing the density, basal diameter of bamboo stem and shoot, tree density and available dry biomass of bamboo, we detected no significant differences between the edges and the interiors of bamboo patches. The possible explanations were analysed and it was deemed that the selection of food habitat near edges by the giant pandas could be attributed to the direct effects of edges, which facilitate movement of the giant pandas in the otherwise dense bamboo patches.
Effect of ejaculate, bull, and a double swim-up sperm processing method on sperm sex ratio
Authors: Madrid-Bury Ninoska , Fernández Raúl , Jiménez Adela , Pérez-Garnelo Sonia , Nuno Moreira Pedro , Pintado Belén , de la Fuente Julio , Gutiérrez-Adán Alfonso
Published: October 2003

Offspring gender preselection has applications of considerable economic, health and ecological interest. In this study we analysed modifications of the percentages of spermatozoa bearing Y and X chromosomes when semen samples are submitted to a double swim-up technique as a possible method for producing embryos of known sex with in vitro fertilisation protocols. As an initial experiment to provide accurate evaluation of the method we determined the possible incidence of natural deviations in the primary sex ratio between bulls or ejaculates, analysing the percentage of Y-chromosome DNA bearing spermatozoa (%Y-CDBS) with a polymerase chain reaction (PCR) amplification of X- and Y-specific fragments. Ejaculates were tested by direct semiquantitative PCR sexing and by sexing blastocysts produced in vitro with these spermatozoa. Bulls and ejaculates did not have any effect on the %Y-CDBS or on the sex ratio of embryos produced in vitro using these ejaculates. However, our double swim-up sperm preparation method produced differences in %Y-CDBS in some of the sperm fractions, suggesting that there are intrinsic differences in capacitation of X- and Y-bearing spermatozoa that might be used to produce embryos of the desired sex with in vitro fertilisation.
Expression of IGF2 and IGF receptor mRNA in bovine nuclear transferred embryos
Authors: Han Dong-Wook , Song Sang-Jin , Uhum Sang Jun , Do Jeong-Tae , Kim Nam-Hyung , Chung Kil-Saeng , Lee Hoon Taek
Published: October 2003

Incomplete reprogramming of the donor cell nucleus after nuclear transfer (NT) probably leads to the abnormal expression of developmentally important genes. This may be responsible for the low efficiency of cloned animal production. Insulin-like growth factor 2 (IGF2) and IGF2 receptor (IGF2R) are imprinted genes that play important roles in preimplantation development. To obtain an insight into abnormal gene expression after nuclear transfer, we assessed the transcription patterns of IGF2-IGF2R in single in vitro fertilised and cloned embryos by reverse-transcription polymerase chain reaction (RT-PCR). IGF2R expression did not differ significantly but IGF2 was more highly expressed in cloned embryos than in IVF embryos (p < 0.05). This was confirmed by a quantitative RT-PCR method. Thus, incomplete reprogramming may induce abnormal transcription of IGF2 in cloned embryos.
Positive and negative changes following vicarious exposure to the September 11 terrorist attacks
Authors: Linley P. Alex , Joseph Stephen , Cooper Rachel , Harris Sophie , Meyer Caroline
Published: October 2003

The negative effects of vicarious traumatic exposure are well known. However, less is known about potential positive changes following vicarious exposure. Respondents living in Britain (n = 108) were surveyed about their vicarious exposure to the terrorist attacks of September 11. They also completed measures of their perceptions of the events of September 11, and positive (valuing friends and family more) and negative changes (loss of meaning, greater anxiety). Results revealed that respondents who perceived the terrorist attacks to be an attack on their own values and beliefs, or the work of religious fanatics, were more likely to report positive changes. Negative and positive psychological changes were positively associated.
Follow‐up of young road accident victims
Authors: Gillies Marjorie L. , Barton Joanne , Gallo Alain Di
Published: October 2003

The aim of this study was to follow‐up a group of children and young people previously examined for psychological sequelae following road traffic accidents. The group was assessed 18‐month postaccident to assess the severity of continuing symptoms and examine any emergence of delayed onset of posttraumatic stress reactions. Participants (N = 31) completed the Revised Impact of Event Scale and the Child Posttraumatic Stress Reaction Index. Parents completed the Child Behavior Check‐List and participated in a semistructured interview. Symptoms of PTSD were noted in a quarter of participants as was delayed onset of symptoms. The role of avoidance in symptom reporting and continuing disorder is discussed.
A description of an HPLC assay of coproporphyrinogen III oxidase activity in mononuclear cells
Authors: Gross U. , Gerlach R. , Kühnel A. , Seifert V. , Doss M. O.
Published: October 2003

Coproporphyrinogen III oxidase is deficient in hereditary coproporphyria. An activity assay for this enzyme in mononuclear cells, besides the preparation of the substrate, are presented. The separation conditions for the product of the test protoporphyrin IX by gradient, reversed‐phase high‐performance liquid chromatography are given. The normal value from mononuclear cells of healthy volunteers was 138±21 pkat/g total soluble protein (mean±SD). The enzyme activity of a family with hereditary coproporphyria was measured. The gene carriers exhibit a specific coproporphyrinogen III oxidase activity of 61–90 pkat/g total soluble protein.
Seismic structure of western end of the Nankai trough seismogenic zone
Authors: Takahashi Narumi , Kodaira Shuichi , Nakanishi Ayako , Park Jin‐Oh , Miura Seiichi , Tsuru Tetsuro , Kaneda Yoshiyuki , Suyehiro Kiyoshi , Kinoshita Hajimu , Hirata Naoshi , Iwasaki Takaya
Published: October 2003

In 1998 a seismic experiment along a 320‐km‐long profile using an air gun array and ocean bottom seismographs (OBSs) was collected in the on shore‐offshore, forearc region of the western Nankai trough seismogenic zone, southwestern Japan. This area is outside the coseismic rupture area of the 1946 Nankaido earthquake (Ms = 8.2). The main objectives of this paper are to clarify the P wave and the Poisson's ratio profile around the forearc region of southwestern Japan, and estimate differences between this area and the Nankaido coseismic rupture area. The P wave velocity model estimated by two‐dimensional (2‐D) ray tracing and travel time inversion indicates three units with distinctive velocity patterns. The lens‐shaped unit has a maximum thickness of 5 km and velocity of 3.4–4.0 km/s. The underlying unit has velocity of 5.4–5.6 km/s, and its P wave velocity increases on land (Vp = 6.2–6.4 km/s). The relative homogeneous unit with P wave velocity of 6.6–6.9 km/s exists just beneath secondary unit with P velocity of 5.4–5.6 km/s. The angle of subduction is ∼7°. We also obtained a Poisson's ratio of the crustal structure of the forearc region. The Poisson's ratio of the southern part of secondary unit is larger than that of the northern part. We conclude that these data indicate clay‐rich metamorphic rocks plus oceanic basaltic rocks, rather than high‐porosity materials, comprise the majority of the layer. We suggest that the region of high Poisson's ratio probably corresponds to underplating and the metamorphism of the clay‐rich sediments and possibly the oceanic basalt just below the decollement.
Diel dynamics of chlorophylls in high‐nutrient, low‐chlorophyll waters of the equatorial Pacific (180°): Interactions of growth, grazing, physiological responses, and mixing
Authors: Neveux Jacques , Dupouy Cécile , Blanchot Jean , Le Bouteiller Aubert , Landry Michael R. , Brown Susan L.
Published: October 2003

In situ diel variations of extracted chlorophyllous pigments, beam attenuation by particles (cp), and in vivo chlorophyll fluorescence (Fiv) were investigated during a 5‐day time series in high‐nutrient, low‐chlorophyll waters of the equatorial Pacific (date line = 180°). Samples were taken hourly at 10 depths in the upper 100 m during the first 48 hours, then sampling frequency decreased to 3 hours. In the 30–70 m layer the integrated chlorophyll concentrations, cp, and Fiv increased during the light period, but the minima and, especially, maxima were not fully synchronized. The lowest values of total chlorophyll a (Tchl a = chlorophyll a + divinyl‐chlorophyll a) occurred around 5–6 hours, slightly (0–2 hours) before that of cp and Fiv. Tchl a reached a maximum around 1500 hours ± 1 hour, clearly before cp (1700 hours) and Fiv (1900 hours). In the 0–30 m layer, diel variations of the integrated chlorophyll concentrations, cp, and Fiv were clearly out of phase. They showed a nocturnal increase in Tchl a, starting around midnight and peaking in early morning (0900 hours). In contrast, cp increased only during the light period in the upper 30 m, and variations of Fiv were largely opposite to those of extracted Tchl a. Specific phytoplankton growth (μ0) and grazing loss (g) rates were estimated from diel variations in the 30–70 m layer and compared to independent rate estimates from experimental incubations. These results are discussed in the context of physical processes and physiological responses of the cells to the daily photocycle.
Stimulated electromagnetic emissions during pump frequency sweep through fourth electron cyclotron harmonic
Authors: Carozzi T. D. , Thidé B. , Grach S. M. , Leyser T. B. , Holz M. , Komrakov G. P. , Frolov V. L. , Sergeev E. N.
Published: October 2003

The frequency of a high‐power HF radio wave incident on the ionosphere was swept, using a computer‐controlled transmitter signal, in <10 s within a 60‐kHz‐wide frequency band approximately centered on the fourth harmonic of the electron cyclotron frequency. Measurements of the spectral behavior of stimulated electromagnetic emissions (SEE) across this harmonic after preconditioning could thereby be made with unprecedented resolution, speed, and ionospheric stability. Comparison of local electron cyclotron frequency estimations based on the experimental data reveals discrepancies between certain downshifted maximum models and the empirical broad upshifted maximum (BUM) feature formula ΔfBUM = f0 − nfce. Weak emissions related to the BUM were discovered below the nominal BUM cutoff frequency. Finally, we observed that the intensity of certain SEE components differed depending on the whether the pump frequency sweep was ascending or descending.
Seismotectonics of the Explorer region
Authors: Braunmiller Jochen , Nábělek John
Published: October 2003

The Explorer region offshore western Canada is a tectonically complex area surrounded by the Pacific, North America, and Juan de Fuca plates. Existing tectonic models for the region differ fundamentally. Proposed plate configurations range from multiple independent plate fragments to an Explorer plate now fused to North America along the continental margin and cut by Pacific–North America transform faults in the west. We present new seismological data constraining the region's current tectonics. We use three‐component regional waveforms to determine the source parameters of 84 earthquakes with magnitude greater than 4. Combined with 34 Harvard centroid moment tensor solutions, they represent the region's largest earthquake source parameter data set obtained by robust waveform modeling techniques. In addition, we perform joint epicenter determination to relocate larger earthquakes recorded since 1918. The source parameters and improved locations provide a consistent tectonic picture. Earthquake slip vector azimuths along the Pacific plate boundary change smoothly and are significantly less northerly oriented than the Pacific‐North America plate motion direction, requiring an independent Explorer plate. The present‐day Pacific‐Explorer boundary is formed by transform faults subparallel to the Revere‐Dellwood‐Wilson fault. Plate motion vectors indicate that the Winona block is part of the Explorer plate. Current Explorer motion is more northerly than indicated by magnetic anomalies prior to 2 Ma, implying a recent change, possibly coinciding with a northwestward ridge jump near Explorer plate's northern end transferring the Winona block from the Pacific to the Explorer plate. In response to these plate motion changes the region north of the western Sovanco fracture zone was assimilated into the Pacific plate. The region around the eastern Sovanco fracture zone, characterized by broadly distributed seismicity, is composed of well‐defined sets of conjugate faults bounding rotating crustal blocks. Earthquake fault strikes agree with the dominant northwest‐southeast fault sets; however, the conjugate sets must be also active to fully accommodate present‐day Explorer plate motion. The SW portion of the strike‐slip Nootka fault zone, the Explorer‐Juan de Fuca plate boundary, is well defined by focused seismicity; however, its full extent under Nootka Island remains unresolved. The Explorer–North America boundary shows sporadic low‐magnitude seismicity. Our Explorer–North America rotation pole predicts convergence varying from negligible at the boundary's northwest end to ∼2 cm/yr at the SE end. This convergence can be accommodated either by subduction or by crustal thickening extending to the North American continent. We favor subduction based on low deformation rates observed by onshore GPS sites. The present Explorer plate system configuration is a result of stepwise reorientation of the Explorer ridge system, each step successively reducing the subduction rate relative to North America.
Propagation of distant tsunamis over slowly varying topography
Authors: Yoon Sung B.
Published: October 2003

A new two‐dimensional finite difference numerical scheme is developed to simulate the propagation of distant tsunamis over slowly varying topography with improved dispersion effect of waves. The new scheme solves the shallow water equations on a uniform grid system. However, the actual computation is made on a hidden grid system whose grid size is adjustable according to the condition required to satisfy local dispersion relationships of waves for varying water depth. The present model is tested for the cases of two‐dimensional propagation of an initial Gaussian hump over various uniform water depth regions. For a varying topography, a one‐dimensional test is conducted. The tests show that accuracy of the numerical model is improved significantly over that of the conventional finite difference models. Finally, the present model is applied to the simulation of a historical tsunami event. The numerical result shows that the submerged rise and ridge play an important role of a waveguide for the tsunamis propagating over that topography.
Variance modeling for nonstationary spatial processes with temporal replications
Authors: Damian Doris , Sampson Paul D. , Guttorp Peter
Published: October 2003

We have previously formulated a Bayesian approach to the Sampson and Guttorp model for the nonstationary correlation functionr(x,x′) of a Gaussian spatial process [Damian et al., 2001]. This model assumes that the nonstationarity can be encoded through a bijective space deformation,f, that defines a new coordinate system in which the spatial correlation function can be considered isotropic, namelyr(x,x′) = ρ(∥f(x) −f(x′)∥), where ρ belongs to a known parametric family. We extend this model to incorporate spatial heterogeneity in site‐specific temporal variances. In our Bayesian framework the variances are considered (hidden) realizations of another spatial process, which we model as log‐Gaussian, with correlation structure expressed in terms of the same spatial deformation function underlying that of the observed process. We demonstrate the method in simulations and in an application.
Mars Exploration Rover mission
Authors: Crisp Joy A. , Adler Mark , Matijevic Jacob R. , Squyres Steven W. , Arvidson Raymond E. , Kass David M.
Published: October 2003

In January 2004 the Mars Exploration Rover mission will land two rovers at two different landing sites that show possible evidence for past liquid‐water activity. The spacecraft design is based on the Mars Pathfinder configuration for cruise and entry, descent, and landing. Each of the identical rovers is equipped with a science payload of two remote‐sensing instruments that will view the surrounding terrain from the top of a mast, a robotic arm that can place three instruments and a rock abrasion tool on selected rock and soil samples, and several onboard magnets and calibration targets. Engineering sensors and components useful for science investigations include stereo navigation cameras, stereo hazard cameras in front and rear, wheel motors, wheel motor current and voltage, the wheels themselves for digging, gyros, accelerometers, and reference solar cell readings. Mission operations will allow commanding of the rover each Martian day, or sol, on the basis of the previous sol's data. Over a 90‐sol mission lifetime, the rovers are expected to drive hundreds of meters while carrying out field geology investigations, exploration, and atmospheric characterization. The data products will be delivered to the Planetary Data System as integrated batch archives.
Refined data of Alpha Proton X‐ray Spectrometer analyses of soils and rocks at the Mars Pathfinder site: Implications for surface chemistry
Authors: Brückner J. , Dreibus G. , Rieder R. , Wänke H.
Published: October 2003

An extensive recalibration of the Alpha Proton X‐ray Spectrometer (APXS) was performed to improve the data evaluation of the Mars Pathfinder (MPF) rock and soil in situ measurements. Many samples and geostandards were measured with an MPF identical spare APXS under simulated Martian atmospheric pressure and low night temperature conditions. Precise calibration curves for major and minor elements were obtained. Using an improved spectral evaluation method for the original MPF spectra, refined and new elemental compositions of the MPF rocks and soils were derived. However, all initial conclusions about soils and rocks remained valid. The MPF soil composition revealed the mafic nature of the surface as inferred from the results of Viking 1 and 2 data. However, the MPF rocks reflect a felsic composition. For all samples, linear correlations of sulphur with all other elements were noticed, reflecting the fact that the rocks were covered with varying degrees of soil, which compared to the rocks is rich in sulphur. Extrapolating to low sulphur abundance (0.3%) the composition of a soil‐free rock was calculated. The MPF rock composition is high in Si and K and low in Mg and Fe compared to the soil. Using elemental data from MPF and Martian meteorites, a global estimation of the Martian crust composition was derived. The crust is of basaltic nature with a high abundance of incompatible elements (K, Rb, Nd, U, Th) and volatile elements (S, Cl), while carbonates are lower or absent.
Treatment of periodontitis in the diabetic patient
Authors: Gustke Carl J.
Published: October 2003

Abstract. Both type 1 and type 2 diabetes mellitus are associated with increased periodontal disease susceptibility. Conventional periodontal therapy appears to be effective in diabetic patients. It has not been demonstrated that chemothera‐peutics are necessary for successful periodontal therapy in most diabetic patients. The effect of periodontal therapy on metabolic control of diabetes may not be clinically significant.
A virtual reality dental simulator predicts performance in an operative dentistry manikin course
Authors: Imber S. , Shapira G. , Gordon M. , Judes H. , Metzger Z.
Published: October 2003

This study was designed to test the ability of a virtual reality dental simulator to predict the performance of students in a traditional operative dentistry manikin course. Twenty‐six dental students were pre‐tested on the simulator, prior to the course. They were briefly instructed and asked to prepare 12 class I cavities which were automatically graded by the simulator. The instructors in the manikin course that followed were unaware of the students' performances in the simulator pre‐test. The scores achieved by each student in the last six simulator cavities were compared to their final comprehensive grades in the manikin course. Class standing of the students in the simulator pre‐test positively correlated with their achievements in the manikin course with a correlation coefficient of 0.49 (P = 0.012). Eighty‐nine percent of the students in the lower third of the class in the pre‐test remained in the low performing half of the class in the manikin course. These results indicate that testing students in a dental simulator, prior to a manikin course, may be an efficient way to allow early identification of those who are likely to perform poorly. This in turn could enable early allocation of personal tutors to these students in order to improve their chances of success.
Molecular and structural characterization of NADPH-dependent d-glycerate dehydrogenase from the enteric parasitic protist Entamoeba histolytica
Authors: ALI Vahab , SHIGETA Yasuo , NOZAKI Tomoyoshi
Published: October 2003

Putative NADPH-dependent GDH (d-glycerate dehydrogenase) of the protozoan parasite Entamoeba histolytica (EhGDH) has been characterized. The EhGDH gene encodes a protein of 318 amino acids with a calculated isoelectric point of 6.29 and a molecular mass of 35.8 kDa. EhGDH showed highest identities with GDH from ε-proteobacteria. This close kinship was also supported by phylogenetic analyses, suggesting possible lateral transfer of the gene from ε-proteobacteria to E. histolytica. In contrast with the implications from protein alignment and phylogenetic analysis, kinetic studies revealed that the amoebic GDH showed biochemical properties similar to those of mammalian GDH, i.e. a preference for NADPH as cofactor and higher affinities towards NADPH and β-hydroxypyruvate than towards NADP+ and d-glycerate. Whereas the amino acids involved in nucleotide binding and catalysis are totally conserved in EhGDH, substitution of a negatively charged amino acid with a non-charged hydroxy-group-containing amino acid is probably responsible for the observed high affinity of EhGDH for NADP+/NADPH. In addition, the amoebic GDH, dissimilar to the bacterial and mammalian GDHs, lacks glyoxylate reductase activity. Native and recombinant EhGDH showed comparable subunit structure, kinetic parameters and elution profiles on anion-exchange chromatography. We propose that the GDH enzyme is likely to be involved in regulation of the intracellular concentration of serine, and, thus, also in controlling cysteine biosynthesis located downstream of serine metabolic pathways in this protist.