bluuebunny/crossref_metadata_2025 huggingface dataset:
The Unending Search for Equity: California Policy, the “Improved School Finance,” and the Williams Case
Authors: Grubb W. Norton , Goe Laura , Huerta Luis A.
Published: October 2004

This article applies the logic of the “improved” school finance, arguing the need to understand how resources are used at the school and classroom levels. While California policies and most court cases have been seriously inadequate from this perspective, the recent case of Williams v. California provides new opportunities for equity since it follows the logic of the “improved” school finance.
High-Stakes Accountability, State Oversight, and Educational Equity
Authors: Mintrop Heinrich
Published: October 2004

This article argues that outcome-based accountability systems are not likely to close the achievement gap. Using California as an example, it suggests that states need to pay closer attention to learning conditions and powerful programs that deliver quality interventions. The article describes the design of the California low-performing schools program, discusses reasons for its limited effectiveness, and suggests design features that may increase the chances for the state to reach its equity goals. The article argues with an eye on California that input-based design features ought to complement outcome-based accountability. Such designs require standards for adequate learning conditions alongside performance standards, mechanisms to detect systemic performance barriers, and the provision of sophisticated evaluation, high-quality support, and consequences for responsible actors.
Racial Isolation, Poverty, and the Limits of Local Control in Oakland
Authors: Noguera Pedro A.
Published: October 2004

Historically, schools in the United States have been governed at the local level by elected school boards, and finances have been raised primarily through local property taxes. While local control theoretically allows for greater responsiveness to local concerns, it does not take into account the vast inequality among and between communities in the United States, nor does it take into account the ways in which poverty can limit the ability of parents in particularly to influence decision making in public schools that serve their children. Drawing on the experience of Oakland, California, this article explores the ways in which poverty and racial discrimination limit the effectiveness of local control as a mechanism for school accountability. It also examines the factors that constrain the ability of schools to be responsive to the needs of the communities that they serve. In making the case for greater parental empowerment in school governance, the article explores how social capital and civic capacity building can enhance the democratic possibilities of local control and help to overcome the effects of concentrated poverty.
Creating a Public Accountability for California Schools
Authors: Rogers John S.
Published: October 2004

This article explores the role of the public in California's educational accountability system. Drawing on a review of state policy and case studies of two school communities, it examines whether California's accountability system draws on and supports an informed and engaged public. The analysis points to a disconnect between a rhetoric that upholds public engagement and policy structures and practices that limit or distort educational information and thwart public efforts to participate in accountability. The article calls on California to nurture an informed and engaged public that will both enable and demand high quality schools.
Civics Lessons: The Color and Class of Betrayal
Authors: Fine Michelle , Burns April , Payne Yasser A. , Torre Maria E.
Published: October 2004

This article draws from research conducted with poor and working-class youth in California attending schools that suffer from structural disrepair, high rates of unqualified teachers, high teacher turnover rates, and inadequate books and instructional materials. Arguing that such schools accomplish more than simple “reproduction” of class and race/ethnic inequities, the authors detail the penetrating psychological, social, and academic impact of such conditions on youth and educators, accelerating schooling for alienation. The evidence suggests that these schools not only systematically undereducate poor and working-class youth, and youth of color, but they taint pride with shame, convert a yearning for quality education into anger at its denial, and they channel active civic engagement into social cynicism and alienation. The consequences for schools, communities, and the democratic fabric of the nation are considered.
A sociolinguistic application of Bakhtin’s authoritative and internally persuasive discourse
Authors: Tsitsipis Lukas D.
Published: October 2004

Through the use of two central Bakhtinian concepts, authoritative and internally persuasive discourse (word), this paper examines the tension between the ideology of linguistic hegemony as a source of power in the Greek public sphere and the condition of language shift faced by the Albanian‐speaking communities of modern Greece. I argue here that a cautious application of these two notions, which are relevant to linguistic ideology, can reveal crucial aspects of two processes: that of subordination to and that of questioning of the dominant linguistic ideology by local Albanian‐speaking communities. Thus, in language shift contexts, it is possible that no simple relations obtain that place social agents in unquestionable and easily predictable positions. Such an approach proves useful for the sociolinguistic study of threatened language communities.
Working hard at giving it away: Lord Duveen, the British Museum and the Elgin marbles
Authors: Kehoe Elisabeth
Published: October 2004

In September 1928, just after the publication of the report of the royal commission on National Museums and Galleries, the art dealer Sir Joseph Duveen wrote to his good friend Edgar Vincent, Viscount D'Abernon, who had chaired the commission, offering to pay for a new gallery at the British Museum to house the Parthenon, or Elgin, marbles. The new gallery cost over £100,000 and took ten years to complete, during which time Duveen worked hard to impose his vision of a new gallery – a vision often at odds with that of the Museum establishment, and one that generated controversy, including the unauthorized cleaning of the marbles.
CONSENT, COMMODIFICATION AND BENEFIT‐SHARING IN GENETIC RESEARCH1
Authors: DICKENSON DONNA
Published: October 2004

The global value of the biotechnology industry is now estimated at 17 billion dollars, with over 1300 firms involved as of the year 2000.2 It has been said that ‘What we are witnessing is nothing less than a new kind of gold rush, and the territory is the body.’ As in previous gold rushes, prospectors are flooding into unexplored and ‘wide open’ territories from all over the world, with possible ramifications for exploitation of Third World populations. These territories are also the Wild West of bioethics insofar as the law has very little hold on them: existing medical and patent law, such as the Moore and Chakrabarty cases, exert little control over powerful economic interests in both the United States and Europe.

In the absence of a unified and consistent law on property in the body, the focus is increasingly on refining the consent approach to rights in human tissue and the human genome, with sensitive and promising developments from the Human Genetics Commission and the Department for International Development consultation on intellectual property. These developments incorporate the views of vulnerable genetic communities such as Native Americans or some Third World populations, and should be welcomed because they recognise the power imbalance between such groups and First World researchers or firms. However, they also highlight the continued tension about what is really wrong with commodifying human tissue or the human genome. Where’s the injustice, and can it be solved by a more sophisticated consent procedure?
Mycobacterium marinum infection of the hand
Authors: RAJADHYAKSHA Samir Anil , KONG Kok Ooi , LIAN Tsui Yee , GOH Lesley‐Ann Hui Huan , FENG Pao Hsii
Published: October 2004

Mycobacterium marinum is an atypical mycobacterium which may cause skin infections, tenosynovitis, arthritis, and osteomyelitis, especially in association with exposure to marine environments. We describe a 59‐year‐old chef with left wrist dorsal tenosynovitis and left third metacarpophalangeal synovitis due to M. marinum. Ultrasonography assisted in confirming the diagnosis of tenosynovitis and obtaining tissue for culture. In comparison to CT scan and MRI scan, ultrasonography has the advantage of being a cheaper imaging modality with no risk of radiation.
Rheumatic disease in the Australian Aborigine of Cape York Peninsula: a 1965 study
Authors: DOUGLAS William Alexander
Published: October 2004

Aim:  To study the prevalence of rheumatic disorders in two Aboriginal populations on the western coast of Cape York Peninsula.

Methods:  Physical and radiological examination of 217 adult Aborigines at Aurukun Aboriginal Mission and 71 Aboriginal adults at Weipa Mission. The study was performed in October 1965.

Results:  Mild to moderate degenerative arthritis was not uncommon in the populations examined. However, generalised or nodal osteoarthritis was not seen. One young woman had definite sero‐positive rheumatoid arthritis. This woman's appearance suggested some Torres Strait Islander influence. No case of gouty arthritis or classical ankylosing spondylitis was encountered. An incidental finding of retrospective interest was that the calculated body mass index showed that the majority of adults were underweight by Caucasian standards.

Conclusions:  These findings are of historic interest given the health impacts of social, cultural and environmental circumstances of Aborigines currently reported.
Weather changes and pain in rheumatology patients
Authors: NG Jennifer , SCOTT David , TANEJA Ashish , GOW Peter , GOSAI Ashmita
Published: October 2004

Objective:  Many rheumatology patients report exacerbation of joint symptoms with weather changes. We report the first of a two‐part study on the influence of weather on rheumatological conditions. This survey aims to describe perceived weather sensitivity in our patient population.

Methods:  Two hundred rheumatology patients seen consecutively in a tertiary hospital were given a 10‐item questionnaire (Jamieson). This questionnaire has been well validated with good test‐retest reliability (r = 0.91) and ability to distinguish patients with weather sensitivity. New patients and soft tissue clinic patients were not included.

Results:  Seventy‐four percent of patients reported weather sensitivity, with humidity and low temperature reported most frequently as being associated with worsening of symptoms (66% and 72%, respectively). Seventy percent of weather sensitive subjects described pain exacerbation prior and/or during weather changes. Various rheumatological conditions had similar rates of weather sensitivity, except fibromyalgia which reported 100% weather sensitivity.

Conclusion:  A significant proportion of rheumatology patients report weather sensitivities. Further studies would be useful to further explore actual versus perceived effects of weather as this may have behavioural, housing and medical implications. Our discussion includes a brief summary of current literature and various postulates why patients may have increased weather sensitivity.
Musculoskeletal medicine: the challenge of the Bone and Joint Decade
Authors: BROOKS P. M.
Published: October 2004

The Bone and Joint Decade (2000–2010) provides a catalyst for the further development of musculoskeletal medicine. The Bone and Joint Decade (BJD) provides an opportunity to bring together industry, governments, health professionals and patients to further research education and services in musculoskeletal diseases.

The challenges for musculoskeletal medicine include an ageing population suffering increasingly from chronic multisystem disease, new technologies including pharmaceuticals, biomaterials and prostheses which come at increasing cost, and a health system which is increasingly required to focus on cost‐effectiveness, patient outcomes and patient involvement.

All those involved in providing services in the area of musculoskeletal medicine have an opportunity to work together and create new systems of healthcare delivery. This is likely to involve a blurring of the barriers between the specialties and the health professions themselves to create a more sustainable, outcomes‐orientated health delivery system. It may lead to task substitution within the musculoskeletal health professionals, the emergence of new forms of ‘generic’ musculoskeletal health professionals and significant changes in the way we delivery education and research. The new ‘musculoskeletal medicine’ will depend much more on inter‐professional training, multidisciplinary research and team management with a patient outcome focus.
Evaluation of Improved Coronary Flow Velocity Reserve Using Transthoracic Doppler Echocardiography After Single LDL Apheresis
Authors: Kobayashi Kengo , Yamashita Kazuhito , Tasaki Hiromi , Suzuka Hiroshi , Nihei Shun‐ichi , Ozumi Kiyoshi , Nakashima Yasuhide
Published: October 2004

Abstract:  The purpose of this study was to clarify whether coronary flow velocity reserve (CFVR), evaluated by adenosine 5′‐triphosphate‐induced hyperemia, is improved by single low‐density lipoprotein (LDL) apheresis. Lipid lowering therapy is known to improve endothelium‐dependent vasodilatation in forearm or coronary resistant vessels. However, few reports have studied the effect of acute LDL reduction on CFVR. Methods: Seven patients with familial hypercholesterolemia and significant coronary stenosis except in the left anterior descending artery (LAD) were enrolled in this study. Coronary flow velocity reserve was estimated before and after LDL apheresis using transthoracic Doppler echocardiography (TTDE), which detects the flow velocity at the distal site of the LAD. Although the averaged diastolic peak velocity (ADPV) during ATP‐induced hyperemia was similar before and after LDL apheresis, the ADPV at baseline decreased from 30.69 to 25.56 cm/s, resulting in an increased CFVR from 1.78 to 2.10 (P < 0.001). Plasma bradykinin and 6 keto PGF1α increased while fibrinogen and plasma viscosity decreased after apheresis. Single LDL apheresis improves CFVR according to TTDE analysis because of the decreasing ADPV at baseline, which is thought to be induced by epicardial coronary artery dilatation and improved microvessel function. This is the result of various factors, such as changes in plasma LDL cholesterol, bradykinin and PGI2 levels with LDL apheresis.
A Last Resort Modality Using Cryofiltration Apheresis for the Treatment of Cold Hemagglutinin Disease in a Veterans Administration Hospital
Authors: Siami Flora S , Siami Ghodrat A
Published: October 2004

Abstract:  Cold hemagglutinin disease is a cold autoimmune hemolytic anemia (cAIHA) caused by an autoantibody, such as IgM, directed against the I‐antigen present on the surface of erythrocytes. Cold exposure can activate this system causing hemolysis, hemagglutination, microvascular thrombosis, or acrocyanosis. Thus, surgical procedures requiring hypothermia, such as coronary artery bypass surgery, present a significant problem in patients with cAIHA. The purpose of this study was to evaluate the safety and effectiveness of cryofiltration apheresis (CFA), used as a last resort, for the treatment of cAIHA. Effectiveness was evaluated by clinical assessment and laboratory evaluations of cold agglutinin titer, immunoglobulins, and other plasma proteins. Safety was evaluated by vital signs, monitoring, and laboratory measurements of complements, hematology and blood chemistry. Five patients with cAIHA were treated by CFA using the cryoglobulin (CG) filter (Pall Medical, Ann Arbor, MI, USA). Four patients received only one CFA procedure, while one patient received four CFA treatments. The cold agglutinin titers were fairly low, ranging from 1 : 1 to 1 : 2048. However, a wide thermal amplitude(4–37°C) was observed in most patients. Two out of five patients responded favorably with reduction in titer. The two responders had acute forms of cAIHA with serum positive for cryoglobulins. The three non‐responders had chronic forms of cAIHA with negative cryoglobulins. CFA effectively removed cryoprotein precipitates while conserving other plasma components. The CG filter was biocompatible with no complement activation or observed complications due to CFA or CG filter. While the mechanism of action in treating this type of patient population with CFA is unknown, the plausible theories are discussed.
Adolescent Girls' Alcohol Use as a Risk Factor for Relationship Violence
Authors: Buzy Wendy Marsh , McDonald Renee , Jouriles Ernest N. , Swank Paul R. , Rosenfield David , Shimek Jennifer S. , Corbitt‐Shindler Deborah
Published: October 2004

This research examined the relation between female adolescents' general alcohol use and their experience of relationship violence. This relation was examined both cross‐sectionally and longitudinally, controlling for the proximal (i.e., situational) effects of alcohol use. One hundred and six female high school students reported on their experiences of physical violence and sexual coercion by boyfriends, general patterns of alcohol use, victimization experiences while drinking, and hypothesized covariates including demographic and relationship variables and illicit drug use. Variables were assessed at 2 time points 4 months apart. Results indicated that general alcohol use was related to victimization both cross‐sectionally and longitudinally, but different findings emerged for different forms of victimization (physical‐only victimization vs. both physical and sexual victimization).
Risk Factors for Adolescent Pregnancy Reports Among African American Males
Authors: Miller‐Johnson Shari , C. Winn Donna‐Marie , Coie John D. , Malone Patrick S. , Lochman John
Published: October 2004

This study examined childhood and adolescent risk factors for males' reports of getting someone pregnant during adolescence. These questions were examined in an urban sample of 335 African American males involved in a prospective, longitudinal study. Childhood aggression significantly predicted reported pregnancies during adolescence. Boys who were stably aggressive across 3rd through 5th grades were at particularly high risk for reporting getting a female pregnant. Adolescent substance use and deviant peer involvement incrementally added to the prediction of pregnancy reports over and above the effects of childhood aggression. Adolescent aggressive problems did not contribute to reports of pregnancy once childhood aggression was accounted for in the model. These results highlight that precursors for males' pregnancy reports can be identified by as early as age 8. Findings also emphasize the importance of an expanded developmental focus to understand risk factors for adolescent pregnancy. The implications of these results are discussed for preventive interventions to reduce adolescent pregnancy.
Sudden Intense Exercise Increases QT Heart Rate Slope and T Wave Complexity in Long QT Syndrome and Normal Subjects
Authors: CHAUHAN VIJAY S. , KRAHN ANDREW D. , MITOFF PETER , KLEIN GEORGE J. , SKANES ALLAN C. , YEE RAYMOND
Published: October 2004

Sudden intense physical activity is a trigger for ventricular arrhythmias in long QT syndrome (LQTS), and β‐blockers (B) reduce the risk of ventricular arrhythmias in LQTS. We compared the effect of graded (gradual intensity) versus burst (sudden intensity) exercise on QT‐rate adaptation and T wave complexity in LQTS + B (n = 21), LQTS − B (n = 5), and normal controls (n = 20). Graded exercise consisted of symptom‐limited bicycle ergometry (30 W, increment 20 W/min). Burst exercise involved a fixed 200 W load for 1.0 minute. ECGs were digitally recorded every 10 seconds during exercise and a 10 minute recovery period. QT‐rate adaptation was quantified using the slope of the QT cycle length relationship fit to a quadratic function. Principle component analysis (PCA) was used to quantify T wave complexity. The QT‐rate slope was two‐fold greater with burst exercise than graded exercise for LQTS + B (−82E ± 40E vs −36E ± 40E, P = 0.0016), LQTS − B (−85E ± 60E vs −30E ± 50E, P = 0.011) and controls (−100E ± 60E vs −48E ± 100E, P = 0.0011) (E = x10−5). For each exercise protocol, there was no difference in QT‐rate slope between the three groups. In contrast, the QT‐rate slope during the 10 minute recovery period was similar between the burst and graded protocol for LQTS + B (25E ± 40E vs 30E ± 50E), LQTS − B (81E ± 80E vs 85E ± 70E) and controls (90E ± 80E vs 82E ± 80E). The coefficient of variability of PCA (T wave complexity variability) during burst exercise was greater than that during graded exercise for LQTS + B (41 ± 15 vs 30 ± 10, P = 0.017), LQTS − B (47 ± 25 vs 26 ± 4, P = 0.016), and control (46 ± 14 vs 33 ± 19, P = 0.012). For each exercise protocol, no difference in T wave complexity variability was seen between the three groups. In conclusion, QT heart rate slope and T wave complexity variability are greater during sudden intense exercise than graded exercise in LQTS patients (on and off β‐blockers) and normal subjects, with similar findings among the three groups of patients.
Right Phrenic Nerve Injury Following Electrical Disconnection of the Right Superior Pulmonary Vein
Authors: LEE BONG‐KI , CHOI KEE‐JOON , KIM JUN , RHEE KYOUNG‐SUK , NAM GI‐BYOUNG , KIM YOU‐HO
Published: October 2004

This report describes a case of transient paresis of the right diaphragm following the transcatheter radiofrequency ablation for the electrical disconnection of pulmonary veins, which recovered completely during the observational period in a 61‐year‐old woman with paroxysmal atrial fibrillation. For electrical disconnection of pulmonary veins, careful preventive measures for phrenic nerve damage are required.
Alleviation of Central Sleep Apnea by Ventricular Pacing in a Patient with an Implanted Cardioverter Defibrillator
Authors: ABE HARUHIKO , KITAMURA TAKURO , OGINOSAWA YASUSHI , NAKASHIMA YASUHIDE
Published: October 2004

A 75‐year‐old man with a single chamber cardioverter defibrillator implanted for the management of sustained ventricular tachycardia developing after a healed myocardial infarction was admitted for evaluation of a sleep disorder. Polysomnography confirmed the presence of severe predominant central sleep apnea syndrome. The apnea‐hypopnea index score decreased from 43.3 during spontaneous cardiac rhythm to 24.6 during VVI pacing at a rate of 70 beats/min . Ventricular pacing reduced the number of episodes of central sleep apnea/hypopnea without reducing the total sleep time, though it had no effect on episodes of obstructive sleep apnea/hypopnea.
Changing practice: The National Literacy Strategy and the politics of literacy policy
Authors: Moss Gemma
Published: October 2004

Drawing on a recent ESRC‐funded research project,1 this paper will explore some of the contradictory structural features of the National Literacy Strategy (NLS), which have helped shape its evolution over time, and reflect on some of the tension points which have arisen at different levels of implementation as the Strategy unfolds. In the process, the paper will consider NLS not so much as a neutral means of transferring ‘what works’ from one site to another, but rather as itself constituting a new social context in which literacy teaching and learning take place. It will pay particular attention to the new pace of teaching that NLS has ushered in and the way in which this is driven by the kind of planning regime that NLS introduced.
Constructs of teacher professionalism within a changing literacy landscape
Authors: Bryan Hazel
Published: October 2004

This paper argues that the work of teachers in England's primary schools has been reconstructed. It is proposed that the literacy curriculum has been a major factor in this reconstruction. The paper suggests that the purposes of literacy today have been determined by policy makers, and that the nature of policy texts has changed, hardened, into specific requirements. It argues that the role of the policy driver has been fundamental in this era, influential in the contexts of policy making, policy text production and teacher training. The paper develops by proposing that there is an emerging model of professionalism today largely determined by two key figures: the Policy Driver, and the Practice Driver, or Headteacher. These two figures are at the meeting place of policy and practice and assume the mantle of ‘reality definers’ for the process of literacy education in English primary schools.
Social interaction and language use in Irish infant classrooms in the context of the revised Irish Primary School Curriculum (1999)
Authors: Murphy Brian
Published: October 2004

This article concerns the gap between government intention and classroom outcome. The author examines the treatment of spoken language in the Revised Irish Curriculum, which came into effect in 1999. He finds much to be commended in the recognition of its central role in learning. He then examines the implementation of this curriculum with children of 5 to 6 years, in fifteen Senior Infant classrooms. Extensive observations and interviews lead him to the view that pupil talk is still seen by most of the teachers observed as a distraction from the essential business of education, namely listening, reading and writing. The interviews revealed that these teachers did not seem to understand the important role of dialogue and discussion in developing learning or recognize the need to promote sustematically opportunities for oral interactions. He concludes that educational change cannot be achieved simply by producing new curriculum statements.
Basic Science: Mechanisms of Medication Overuse Headache
Authors: Meng Ian D. , Porreca Frank
Published: October 2004

Headache caused by overuse of symptomatic medications to treat headache represents a challenging clinical problem. Recent studies exploring both the mechanisms of migraine headache and neuroplastic changes following sustained exposure to analgesic drugs suggest insights regarding the pathophysiology of medication overuse headache. In this review, changes that occur following chronic morphine that may be particularly relevant to the induction of medication overuse headache will be discussed. Peripherally, these changes include increased expression of calcitonin gene‐related peptide (CGRP) in primary afferent neurons. Centrally, they include increased descending facilitation from the rostral ventromedial medulla and increased excitatory neurotransmission at the level of the dorsal horn. Interestingly, many of these same changes, including increased CGRP levels and peripheral and central sensitization, are apparent in inflammatory pain states. Recent revelations into the mechanisms of migraine headache suggest that neurogenic inflammation leads to both peripheral and central sensitization in the migraine sufferer. Furthermore, CGRP plays a prominent role in initiating vasodilation of the intracranial blood vessels and subsequent headache. Given the many parallels between the effects of chronic morphine exposure and processes that occur during migraine, it is evident that overuse of symptomatic medications to treat headache could lead to worsening of symptoms. In animals, the neural adaptations that occur after sustained morphine exposure are manifested behaviorally as an increased sensitivity to both tactile and thermal stimulation. In the headache sufferer, these adaptations could lead to medication overuse headache.
Metabotropic glutamate receptors modulate feedback inhibition in a developmentally regulated manner in rat dentate gyrus
Authors: Doherty James J. , Alagarsamy Sudar , Bough Kristopher J. , Conn P. Jeffrey , Dingledine Raymond , Mott David D.
Published: October 2004

We investigated group II metabotropic glutamate receptor (mGluR) modulation of glutamatergic input onto hilar‐border interneurones and its regulation of feedback inhibition in the dentate gyrus. Selective activation of group II mGluRs with (2S,2′R,3′R)‐2‐(2′,3′‐dicarboxycyclopropyl)glycine (DCG‐IV) depressed mossy fibre (MF)‐evoked excitatory drive to these interneurones with significantly greater depression in juvenile than adult rats. During 20 Hz MF stimulus trains, EPSCs became depressed. Depression during the early, but not later part of the train was significantly greater in juvenile than adult rats and was blocked by the mGluR antagonist (2S)‐2‐amino‐2‐[(1S,2S)‐2‐carboxycycloprop‐1‐yl]‐3‐(xanth‐9‐yl) propanoic acid (LY341495). In dentate granule cells from juvenile rats polysynaptic feedback IPSCs, but not monosynaptic IPSCs, were strongly suppressed by DCG‐IV. DCG‐IV also suppressed feedback inhibition of perforant path‐evoked population spikes. In contrast, in adult animals DCG‐IV did not significantly depress feedback inhibition. During 20 Hz stimulus trains in juvenile animals the summation of polysynaptic, but not monosynaptic IPSCs was suppressed by synaptically activated group II mGluRs. Blockade of these mGluRs with LY341495 significantly increased the area and duration of the summated IPSC, causing greater feedback inhibition of granule cell firing. In contrast, in adult animals LY341495 did not alter feedback inhibition following the stimulus train. These findings indicate that group II mGluRs modulate excitatory drive to interneurones in a developmentally regulated manner and thereby modulate feedback inhibition in the dentate gyrus.
Unified Kinematic Analysis of General Planar Parallel Manipulators
Authors: Hayes M. J. D. , Zsombor-Murray P. J. , Chen C.
Published: October 2004

A kinematic mapping of planar displacements is used to derive generalized constraint equations having the form of ruled quadric surfaces in the image space. The forward kinematic problem for all three-legged, three-degree-of-freedom planar parallel manipulators thus reduces to determining the points of intersection of three of these constraint surfaces, one corresponding to each leg. The inverse kinematic solutions, though trivial, are implicit in the formulation of the constraint surface equations. Herein the forward kinematic solutions of planar parallel robots with arbitrary, mixed leg architecture are exposed completely, and in a unified way, for the first time.
An Experimental Study of Self-Loosening of Bolted Joints
Authors: Jiang Yanyao , Zhang Ming , Park Tae-Won , Lee Chu-Hwa
Published: October 2004

The self-loosening process of a bolted joint consists of two distinct stages. The early stage of self-loosening is due to the cyclic plastic deformation of the materials. The second stage of self-loosening is characterized by the backing off of the nut. The current work is concentrated on an experimental investigation of the second stage self-loosening. Over one hundred bolted joints with M12×1.75 bolts and nuts were experimentally tested using a specially designed testing apparatus. The experiments mimicked two plates jointed by a bolt and a nut and were subjected to cyclic transverse shear loading. During an experiment, the relative displacement between the two clamped plates, denoted by δ, was a controlling parameter. For a given preload, the relationship between, Δδ/2, the amplitude of the relative displacement between the two clamped plates, and, NL, the number of loading cycles to loosening followed a pattern similar to a fatigue curve. There existed an endurance limit below which self-loosening would not persist. A larger preload resulted in a larger endurance limit. However, a large preload increased the possibility for the bolt to fail in fatigue. The results suggest that the use of a regular nut is superior to the use of a flange nut in terms of self-loosening resistance.
Evaluation of the Effect of Misalignment and Profile Modification in Face Gear Drive by a Finite Element Meshing Simulation
Authors: Barone Sandro , Borgianni Leonardo , Forte Paola
Published: October 2004

Face gear drives have many advantages over other cross axis transmissions especially in high performance applications. The lack of published design experience and design standards make their design difficult. This is mainly due to the complex geometries and to the lack of practical experience. For these reasons face gears have not been used for long. This work is aimed at investigating the behavior of a face gear transmission considering contact path under load, load sharing and stresses, for an unmodified gear set including shaft misalignment and modification on pinion profile. The investigation is carried out by integrating a 3D CAD system and a FEA code, and by simulating the meshing of pinion and gear sectors with three teeth, using contact elements and an automated contact algorithm. The procedures followed to create the 3D models of teeth in mesh are described and finite element analysis results discussed showing the differences between unmodified, modified and misaligned teeth. Results show the influence of load on theoretically calculated contact paths, contact areas, arc of action and load sharing. The differences with respect to the ideal case are sometimes remarkable. Further developments are discussed.
The 3-RRS Wrist: A New, Simple and Non-Overconstrained Spherical Parallel Manipulator
Authors: Di Gregorio Raffaele
Published: October 2004

Orientating a rigid body without changing its position is required in many technical applications. This manipulation task is accomplished by manipulators (spherical manipulators) that are just able to make the end effector move according to controlled spherical motions. Spherical manipulators can be either serial or parallel. Parallel architectures are usually more stiff and precise than the serial ones, whereas their structures are more complex than the serial ones. This paper presents a new three-equal-legged spherical parallel manipulator, named the 3-RRS wrist. The 3-RRS wrist is not overconstrained and exhibits a simple architecture employing just three passive revolute pairs, three passive spherical pairs and three actuated revolute pairs adjacent to the frame. The kinematic analysis of the 3-RRS wrist is addressed and fully solved. Finally, its singularity conditions are written in explicit form and discussed. The results of this analysis lead to the conclusion that the new manipulator has only two types of singularities both easy to be identified with geometric reasoning.
Protein Kinase C Overactivity Impairs Prefrontal Cortical Regulation of Working Memory
Authors: Birnbaum S. G. , Yuan P. X. , Wang M. , Vijayraghavan S. , Bloom A. K. , Davis D. J. , Gobeske K. T. , Sweatt J. D. , Manji H. K. , Arnsten A. F. T.
Published: October 2004

The prefrontal cortex is a higher brain region that regulates thought, behavior, and emotion using representational knowledge, operations often referred to as working memory. We tested the influence of protein kinase C (PKC) intracellular signaling on prefrontal cortical cognitive function and showed that high levels of PKC activity in prefrontal cortex, as seen for example during stress exposure, markedly impair behavioral and electrophysiological measures of working memory. These data suggest that excessive PKC activation can disrupt prefrontal cortical regulation of behavior and thought, possibly contributing to signs of prefrontal cortical dysfunction such as distractibility, impaired judgment, impulsivity, and thought disorder.
A Molecular Switch and Proton Wire Synchronize the Active Sites in Thiamine Enzymes
Authors: Frank René A. W. , Titman Christopher M. , Pratap J. Venkatesh , Luisi Ben F. , Perham Richard N.
Published: October 2004

Thiamine diphosphate (ThDP) is used as a cofactor in many key metabolic enzymes. We present evidence that the ThDPs in the two active sites of the E1 (EC 1.2.4.1) component of the pyruvate dehydrogenase complex communicate over a distance of 20 angstroms by reversibly shuttling a proton through an acidic tunnel in the protein. This “proton wire” permits the co-factors to serve reciprocally as general acid/base in catalysis and to switch the conformation of crucial active-site peptide loops. This synchronizes the progression of chemical events and can account for the oligomeric organization, conformational asymmetry, and “ping-pong” kinetic properties of E1 and other thiamine-dependent enzymes.
Harnessing Chaperones to Generate Small-Molecule Inhibitors of Amyloid ß Aggregation
Authors: Gestwicki Jason E. , Crabtree Gerald R. , Graef Isabella A.
Published: October 2004

Protein aggregation is involved in the pathogenesis of neurodegenerative diseases and hence is considered an attractive target for therapeutic intervention. However, protein-protein interactions are exceedingly difficult to inhibit. Small molecules lack sufficient steric bulk to prevent interactions between large peptide surfaces. To yield potent inhibitors of β-amyloid (Aβ) aggregation, we synthesized small molecules that increase their steric bulk by binding to chaperones but also have a moiety available for interaction with Aβ. This strategy yields potent inhibitors of Aβ aggregation and could lead to therapeutics for Alzheimer's disease and other forms of neurodegeneration.
Runcaria
, a Middle Devonian Seed Plant Precursor
Authors: Gerrienne P. , Meyer-Berthaud B. , Fairon-Demaret M. , Streel M. , Steemans P.
Published: October 2004

The emergence of the seed habit in the Middle Paleozoic was a decisive evolutionary breakthrough. Today, seed plants are the most successful plant lineage, with more than 250,000 living species. We have identified a middle Givetian (385 million years ago) seed precursor from Belgium predating the earliest seeds by about 20 million years.
Runcaria
is a small, radially symmetrical, integumented megasporangium surrounded by a cupule. The megasporangium bears an unopened distal extension protruding above the multilobed integument. This extension is assumed to be involved in anemophilous pollination.
Runcaria
sheds new light on the sequence of character acquisition leading to the seed.
Energetics of Hydrogen Bond Network Rearrangements in Liquid Water
Authors: Smith Jared D. , Cappa Christopher D. , Wilson Kevin R. , Messer Benjamin M. , Cohen Ronald C. , Saykally Richard J.
Published: October 2004

A strong temperature dependence of oxygen K-edge x-ray absorption fine structure features was observed for supercooled and normal liquid water droplets prepared from the breakup of a liquid microjet. Analysis of the data over the temperature range 251 to 288 kelvin (–22° to +15°C) yields a value of 1.5 ± 0.5 kilocalories per mole for the average thermal energy required to effect an observable rearrangement between the fully coordinated (“ice-like”) and distorted (“broken-donor”) local hydrogen-bonding configurations responsible for the pre-edge and post-edge features, respectively. This energy equals the latent heat of melting of ice with hexagonal symmetry (ice Ih) and is consistent with the distribution of hydrogen bond strengths obtained for the “overstructured” ST2 model of water.
Partner-Specific Odor Recognition in an Antarctic Seabird
Authors: Bonadonna Francesco , Nevitt Gabrielle A.
Published: October 2004

Among birds, the Procellariiform seabirds (petrels, albatrosses, and shearwaters) are prime candidates for using chemical cues for individual recognition. These birds have an excellent olfactory sense, and a variety of species nest in burrows that they can recognize by smell. However, the nature of the olfactory signature--the scent that makes one burrow smell more like home than another--has not been established for any species. Here, we explore the use of intraspecific chemical cues in burrow recognition and present evidence for partner-specific odor recognition in a bird.
Critical-Like Phenomena Associated with Liquid-Liquid Transition in a Molecular Liquid
Authors: Kurita Rei , Tanaka Hajime
Published: October 2004

Contrary to the conventional wisdom that there is only one unique liquid state for any material, recent evidence suggests that there can be more than two liquid states even for a single-component substance. The transition between these liquid states is called a liquid-liquid phase transition. We report the detailed experimental investigation on the kinetics of the continuous spinodal-decomposition-type transformation of one liquid into another for triphenyl phosphite. From the analysis of the linear regime, we found that the correlation length, ξ, of fluctuations of the relevant order parameter diverges as ξ = ξ
0
[(
T
SD
–
T
)/
T
SD
]
–ν
(where ξ
0
= 60 nm and ν = 0.5) while approaching the spinodal temperature,
T
SD
. This is an indication of a critical-like anomaly associated with the liquid-liquid transition. We also revealed that the order parameter governing the liquid-liquid transition must be of a nonconserved nature.
Life from Repeated Parts
Authors: Meyers Lauren Ancel
Published: October 2004

Modularity in Development and Evolution
. Gerhard Schlosser and Günter P. Wagner, Eds. University of Chicago Press, Chicago, 2004. 610 pp. $90, £63. 0-226-73853-1. Paper, $35, £24.50. ISBN 0-226-73855-8.

The contributors explore what modularity is, how it can be recognized, how it arises and changes through evolution, and its biological significance.
Symmetry Breaking and the Evolution of Development
Authors: Palmer A. Richard
Published: October 2004

Because of its simplicity, the binary-switch nature of left-right asymmetry permits meaningful comparisons among many different organisms. Phylogenetic analyses of asymmetry variation, inheritance, and molecular mechanisms reveal unexpected insights into how development evolves. First, directional asymmetry, an evolutionary novelty, arose from nonheritable origins almost as often as from mutations, implying that genetic assimilation (“phenotype precedes genotype”) is a common mode of evolution. Second, the molecular pathway directing hearts leftward—the nodal cascade—varies considerably among vertebrates (homology of form does not require homology of development) and was possibly co-opted from a preexisting asymmetrical chordate organ system. Finally, declining frequencies of spontaneous asymmetry reversal throughout vertebrate evolution suggest that heart development has become more canalized.
Changing Genes to Feed the World
Authors: Pimentel David
Published: October 2004

Mendel in the Kitchen
A Scientist's View of Genetically Modified Foods. by Nina Fedoroff and Nancy Marie Brown. Joseph Henry Press, Washington, DC, 2004. 366 pp. $24.95, C$32.95. ISBN 0-309-09205-1.

In this account of the history and technology of genetically modified foods (written for a broad, nonspecialist audience), the authors argue that new molecular approaches offer an environmentally friendly approach to increasing the world's food supply.
PROGRESS IN OPTICAL FIBER AMPLIFIERS
Authors: SUDO SHOICHI
Published: October 2004

Recent progress in fiber amplifier technology is reviewed. Broad band and high power are currently the key goals in the field of fiber amplifiers in conjunction with amplified system development. Broad-band EDFAs using fluoride-based hosts and high-power EDFAs with powerful pump lasers are described in detail. Recent progress and other requirements for optical amplifiers i.e. high gain, low noise, and high reliability, are all reviewed. The limitations in relation to achievable gain are described as well as the highest gain ever achieved. A method for its reduction are described. In relation to reliability, this paper mainly focuses on fluoride fiber. Recent progress on the main characteristics of 1.3 µm PDFA is reviewed and transmission experiment are described. Several attempts to construct fiber amplifiers operating at 0.8 µm, 1.4 µm, and 1.65 µm are also reviewed. In the field of amplified systems, WDM and remote pumping TDM techniques are a high priority. In particular, various WDM experiments such as long-distance WDM transmission, WDM soliton transmission, and WDM networks are all described in detail.
InP-BASED OPTICAL SWITCH ARRAYS USING SEMICONDUCTOR OPTICAL AMPLIFIERS
Authors: KIRIHARA TOSHIO , INOUE HIROAKI
Published: October 2004

We present a review of optical switch arrays using semiconductor optical amplifiers. The combination of active and passive switching components and of gate and booster amplifiers is discussed from the viewpoint of the relation between their designs and switching characteristics: loss compensation, crosstalk, spontaneous emission noise, and gain saturation. Demonstrations of carrier-injection type single-slip structure ( S 3) switch with traveling amplifier (COSTA) were reviewed to illustrate the device integration techniques and their potential usefulness in large-scale photonic switching systems even in the presence of spontaneous emission from integrated optical amplifiers.
ULTRAFAST OPTICAL TIME DEMULTIPLEXERS USING SEMICONDUCTOR OPTICAL AMPLIFIERS
Authors: KANG K. I. , GLESK I. , PRUCNAL P. R.
Published: October 2004

The operating principle of the utilization of resonant optical nonlinearities in recently demonstrated ultra-fast all-optical interferometric switching devices is presented. Optimum switching windows expected from these devices are investigated with a simple theoretical analysis. The experimental results of these devices are presented along with the nonlinear optical properties of a semiconductor optical amplifier. The information from the experimental results of the nonlinear optical properties are used to address a problem associated with a saturation of the semiconductor optical amplifier by an incoming ultra-high bit rate data stream. We also discuss the advantages and disadvantages in different operation modes — same or different wavelengths for the control and data signals. Finally, we discuss the relative advantages and disadvantages among these devices.
LOW POWER DESIGN OF OFF-CHIP DRIVERS AND TRANSMISSION LINES: A BRANCH AND BOUND APPROACH
Authors: GUPTA ROHINI , WILLIS JOHN , PILEGGI LAWRENCE T.
Published: October 2004

As electronic systems grow in functional complexity, hence size, the design is often forced into a multi-chip solution. For such systems, the power dissipation due to the off-chip drivers (OCDs) and the off-chip interconnect capacitance can contribute to a significant portion of the overall system power. Often, however, this excessive power dissipation is unwarranted, since a smaller OCD can be used to drive the transmission line load, hence reducing the net capacitance being switched. The objective of this paper is to enable power dissipation trade-off decisions during the high-level phases of design and to minimize the power dissipation of OCDs and their associated interconnect. First, a termination metric is described that uses width optimization of RLC interconnects. Then, in terms of a proposed linear driver model, the low power design objective is posed as an integer programming problem and a branch and bound enumeration algorithm is presented. The driver and interconnect sizes are determined which will preserve signal quality, dispense with additional termination components, meet delay requirements, and minimize the overall power dissipation.