bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional effects of 20-HETE on human bronchi: hyperpolarization and relaxation due to BKCa channel activation
Authors: Morin Caroline , Sirois Marco , Echave Vincent , Gomes Marcio M. , Rousseau Eric
Published: July 2007

Airway smooth muscle (ASM) metabolizes arachidonic acid (AA) through various enzymatic pathways, including cytochrome P-450 (CYP-450) ω-hydroxylase, which leads to the production of 20-hydroxyeicosatetraenoic acid (20-HETE). The goal of this study was to delineate the mode of action of 20-HETE in human ASM cells. Isometric tension measurements demonstrated that 20-HETE induced a concentration-dependent relaxant effect in ASM on bronchi precontracted with either methacholine or AA. Relaxing effects of 20-HETE on resting tone were prevented by 10 nM iberiotoxin (IbTx), a BKCa channel inhibitor. Microelectrode measurements showed that exogenous additions of 20-HETE (0.1–10 μM) hyperpolarized the membrane potential of human ASM cells. This concentration-dependent electrophysiological effect induced by the eicosanoid was prevented by 10 nM IbTx. Complementary experiments, using the planar lipid bilayer reconstitution technique, demonstrated that 20-HETE activated reconstituted BKCa channels at low free Ca2+ concentrations. Together, these results indicate that 20-HETE-dependent activation of BKCa channels is responsible for the hyperpolarization and controlled relaxation of ASM in human distal bronchi.
Multifaceted Dysregulation of the Epidermal Growth Factor Receptor Pathway in Clear Cell Sarcoma of the Kidney
Authors: Little Suzanne E. , Bax Dorine A. , Rodriguez-Pinilla Maria , Natrajan Rachael , Messahel Boo , Pritchard-Jones Kathy , Vujanic Gordan M. , Reis-Filho Jorge S. , Jones Chris
Published: July 2007

Purpose: Epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase overexpressed in a variety of human malignancies, against which targeted therapies have shown efficacy in lung and brain tumors. Clinical responses to EGFR inhibitors have been found to be highly dependent on the presence of activating mutations, whereas gene amplification, downstream activation of Akt, and abnormalities in PTEN are also reported predictive factors. We sought to evaluate these variables in pediatric renal tumors.

Experimental Design: We screened a series of 307 pediatric renal tumors for EGFR expression by immunohistochemistry and gene amplification by chromogenic in situ hybridization. In identifying a striking predilection for certain tumor types, we further analyzed the clear cell sarcomas of the kidney (CCSK) for mutations in EGFR and PTEN.

Results: Although only 23 of 177 (13.0%) nonanaplastic Wilms' tumors were EGFR positive, 4 of 11 (36.4%) anaplastic tumors showed receptor overexpression. In addition, 5 of 9 (55.6%) mesoblastic nephromas and 12 of 12 (100%) CCSKs were strongly immunoreactive for EGFR. In studying the CCSKs in more detail, we identified gene amplification in 1 of 12 (8.3%) cases and a somatic T790M EGFR mutation in a further case. These two samples additionally harbored mutations in PTEN. Downstream pathway activation, as assayed by phosphorylated Akt expression, was observed in 8 of 12 (66.7%) cases.

Conclusions: Together, these data show dysregulation of the EGFR pathway at multiple levels in CCSKs. Identification of factors predictive of poor response to targeted therapy, including the drug resistance T790M mutation, may provide a rationale for upfront trials with irreversible inhibitors of EGFR in children with these tumors.
Persistent Use of Evidence-Based Pharmacotherapy in Heart Failure Is Associated With Improved Outcomes
Authors: Gislason Gunnar H. , Rasmussen Jeppe N. , Abildstrom Steen Z. , Schramm Tina Ken , Hansen Morten Lock , Buch Pernille , Sørensen Rikke , Folke Fredrik , Gadsbøll Niels , Rasmussen Søren , Køber Lars , Madsen Mette , Torp-Pedersen Christian
Published: July 2007

Background—

Undertreatment with recommended pharmacotherapy is a common problem in heart failure and may influence prognosis. We studied initiation and persistence of evidence-based pharmacotherapy in 107 092 patients discharged after first hospitalization for heart failure in Denmark from 1995 to 2004.

Methods and Results—

Prescriptions of dispensed medication and mortality were identified by an individual-level linkage of nationwide registers. Inclusion was irrespective of left ventricular function. Treatment with renin-angiotensin inhibitors (eg, angiotensin-converting enzyme inhibitors and angiotensin-2 receptor blockers), β-blockers, spironolactone, and statins was initiated in 43%, 27%, 19%, and 19% of patients, respectively. Patients who did not initiate treatment within 90 days of discharge had a low probability of later treatment initiation. Treatment dosages were in general only 50% of target dosages and were not increased during long-term treatment. Short breaks in therapy were common, but most patients reinitiated treatment. Five years after initiation of treatment, 79% patients were still on renin-angiotensin inhibitors, 65% on β-blockers, 56% on spironolactone, and 83% on statins. Notably, multiple drug treatment and increased severity of heart failure was associated with persistence of treatment. Nonpersistence with renin-angiotensin inhibitors, β-blockers, and statins was associated with increased mortality with hazard ratios for death of 1.37 (95% CI, 1.31 to 1.42), 1.25 (95% CI, 1.19 to 1.32), 1.88 (95% CI, 1.67 to 2.12), respectively.

Conclusions—

Persistence of treatment was high once medication was started, but treatment dosages were below recommended dosages. Increased severity of heart failure or increased number of concomitant medications did not worsen persistence, but nonpersistence identified a high-risk population of patients who required special attention. A focused effort on early treatment initiation, appropriate dosages, and persistence with the regimen is likely to provide long-term benefit.
Stromal Cell–Derived Factor-1α Confers Protection Against Myocardial Ischemia/Reperfusion Injury
Authors: Hu Xiaofeng , Dai Shujing , Wu Wen-Jian , Tan Wei , Zhu Xiaoping , Mu Jingyao , Guo Yiru , Bolli Roberto , Rokosh Gregg
Published: July 2007

Background—

Stromal cell–derived factor-1α (SDF-1α) binding to its cognate receptor, CXCR4, regulates a variety of cellular functions such as stem cell homing, trafficking, and differentiation. However, the role of the SDF-1α–CXCR4 axis in modulating myocardial ischemia/reperfusion injury is unknown.

Methods and Results—

In mice subjected to ischemic preconditioning, myocardial SDF-1α mRNA was found to be increased 3 hours later (
P
<0.05). Myocardial SDF-1α and CXCR4 mRNA and protein were found to be expressed in both cardiac myocytes and fibroblasts. SDF-1α production increased significantly after 1 or 4 hours of hypoxia and 18 hours of reoxygenation in cultured myocytes (
P
<0.05) but did not change in fibroblast cultures. In isolated myocytes, CXCR4 activation by SDF-1α resulted in increased phosphorylation of both ERK 1/2 and AKT and decreased phosphorylation of JNK and p38. Cultured myocytes pretreated with SDF-1α were resistant to hypoxia/reoxygenation damage, exhibiting less lactate dehydrogenase release, trypan blue uptake, and apoptotic cell death (terminal deoxynucleotidyl transferase–mediated dUTP nick-end labeling assay) (
P
<0.05). This protective effect was blocked by the CXCR4 selective antagonist AMD3100. In vivo, administration of SDF-1α before 30 minutes of coronary occlusion followed by 4 hours of reperfusion decreased infarct size (
P
<0.05). The decrease in infarct size with SDF-1α administration also was blocked by AMD3100.

Conclusions—

We conclude that SDF-1α and its receptor, CXCR4, constitute a paracrine or autocrine axis in cardiac myocytes that is activated in response to preconditioning and hypoxic stimuli, recruiting the antiapoptotic kinases ERK and AKT and promoting an antiapoptotic program that confers protection against ischemia/reperfusion damage.
Giα1-Mediated Cardiac Electrophysiological Remodeling and Arrhythmia in Hypertrophic Cardiomyopathy
Authors: Ruan Hongmei , Mitchell Scherise , Vainoriene Monika , Lou Qing , Xie Lai-Hua , Ren Shuxun , Goldhaber Joshua I. , Wang Yibin
Published: July 2007

Background—

Cardiac hypertrophy is a major risk factor for arrhythmias and sudden cardiac death. However, the underlying signaling mechanisms involved in the induction of arrhythmia and electrophysiological remodeling in cardiac hypertrophy are unclear.

Methods and Results—

Using an inducible gene-switch approach, we achieved tissue-specific and temporally regulated induction of a well-established hypertrophic pathway, the Ras-Raf–mitogen-activated protein kinases pathway, in adult mouse heart. On Ras activation, the transgenic animal developed ventricular hypertrophy and arrhythmias. The development of ventricular arrhythmias was temporally correlated with electrophysiological remodeling in isolated ventricular myocytes, including action potential prolongation, increased sodium-calcium exchanger activity, reduced outward potassium currents, sarcoplasmic reticulum Ca
2+
defects, and loss of protein kinase A–dependent phospholamban phosphorylation. From genome-wide expression profiling, we discovered a selective induction of Gα inhibiting subunit 1 (Giα1) expression in the Ras transgenic heart. Treatment of transgenic animals with the Gi/o inhibitor pertussis toxin normalized the phospholamban phosphorylation by protein kinase A, reversed the action potential prolongation, and significantly reduced the frequency of cardiac arrhythmias in Ras transgenic animals.

Conclusions—

These data suggest that selective induction of Gα inhibiting subunit 1 expression and activity is a novel downstream event in hypertrophic signaling that may be a critical factor leading to cellular electrophysiological remodeling and cardiac arrhythmias in hypertrophic cardiomyopathy.
Family History of Premature Coronary Heart Disease and Coronary Artery Calcification
Authors: Nasir Khurram , Budoff Matthew J. , Wong Nathan D. , Scheuner Maren , Herrington David , Arnett Donna K. , Szklo Moyses , Greenland Philip , Blumenthal Roger S.
Published: July 2007

Background—

A family history of premature coronary heart disease (CHD) is a known risk factor for CHD events. The purpose of this study was to assess the strength of the association between a family history of premature CHD and coronary artery calcification (CAC) in a multiethnic cohort of asymptomatic individuals. We also sought to determine whether individuals with a reported family history of premature CHD have an increased atherosclerotic burden among those classified as being at low to intermediate risk on the basis of the conventional Framingham risk score.

Methods and Results—

The association of family history of premature CHD with CAC was assessed in 5347 asymptomatic individuals (47% men; mean age 62±10 years) in the Multi-Ethnic Study of Atherosclerosis (MESA). The demographics (age, gender, and race)–adjusted OR for CAC >0 with versus without a family history of premature CHD was 1.94 (95% CI, 1.64 to 2.29). On adjustment for CHD risk factors, the association was slightly attenuated to an OR of 1.84 (95% CI, 1.55 to 2.19). Family history of premature CHD was significantly associated with CAC in all ethnic groups. The age-, gender-, and race-adjusted prevalence of CAC >0 was significantly higher with presence of any family history of premature CHD than for those with no family history of premature CHD among individuals classified as low risk (35% versus 23%,
P
<0.0001) and among those at intermediate risk (70% versus 60%,
P
=0.01). Similarly, the prevalence of age-gender-race–based CAC ≥75th percentile in low-risk (24% versus 14%,
P
=0.0003) and intermediate-risk (34% versus 20%,
P
<0.001) individuals was also higher among those with a family history of premature CHD. Compared with those without a family history of premature CHD, the association with the presence of CAC was strongest in participants reporting such history in both a parent and a sibling (odds ratio, 2.74; 95% CI, 1.64 to 4.59), followed by those reporting a family history in a sibling only (odds ratio, 2.06; 95% CI, 1.64 to 2.58) and those reporting a family history of premature CHD only in a parent (odds ratio, 1.52; 95% CI, 1.19 to 1.93).

Conclusions—

An association between family history of premature CHD and the presence of any CAC, as well as advanced CAC, was observed in the present population-based multiethnic study. The relationship was independent of other risk factors and Framingham risk score, which supports the utility of including information on family history of premature CHD in current methods of global risk assessment and practice guidelines.
Essential Role for Prolyl Hydroxylase Domain Protein 2 in Oxygen Homeostasis of the Adult Vascular System
Authors: Takeda Kotaro , Cowan Ann , Fong Guo-Hua
Published: July 2007

Background—

Prolyl hydroxylase domain (PHD) proteins, including PHD1, PHD2, and PHD3, mediate oxygen-dependent degradation of hypoxia-inducible factor (HIF)-α subunits. Although angiogenic roles of hypoxia-inducible factors are well known, the roles of PHDs in the vascular system remain to be established.

Methods and Results—

We evaluated angiogenic phenotypes in mice carrying targeted disruptions in genes encoding different PHD isoforms. Although
Phd1
−/−
and
Phd3
−/−
mice did not display apparent angiogenic defects, broad-spectrum conditional knockout of
Phd2
led to hyperactive angiogenesis and angiectasia. Blood vessels in PHD2-deficient mice were highly perfusable. Furthermore, examination of medium-sized vessels in subendocardial layer in the heart demonstrated successful recruitment of vascular smooth muscle cells. Surprisingly, increased vascular growth was independent of local efficiency of
Phd2
disruption. Mice carrying significant
Phd2
disruption in multiple organs, including the liver, heart, kidney, and lung, displayed excessive vascular growth not only in these organs but also in the brain, where
Phd2
disruption was very inefficient. More surprisingly, increased accumulation of hypoxia-inducible factor-1α and angiectasia in the liver were not accompanied by corresponding increases in hepatic expression of
Vegfa
or
angiopoietin-1
. However, the serum vascular endothelial growth factor-A level was significantly increased in PHD2-deficient mice.

Conclusions—

PHD2, but not PHD1 and PHD3, is a major negative regulator for vascular growth in adult mice. Increased angiogenesis in PHD2-deficient mice may be mediated by a novel systemic mechanism.
Point Mutation in the HCN4 Cardiac Ion Channel Pore Affecting Synthesis, Trafficking, and Functional Expression Is Associated With Familial Asymptomatic Sinus Bradycardia
Authors: Nof Eyal , Luria David , Brass Dovrat , Marek Dina , Lahat Hadas , Reznik-Wolf Haya , Pras Elon , Dascal Nathan , Eldar Michael , Glikson Michael
Published: July 2007

Background—The hyperpolarization-activated nucleotide-gated channel-HCN4 plays a major role in the diastolic depolarization of sinus atrial node cells. Mutant HCN4 channels have been found to be associated with inherited sinus bradycardia.

Methods and Results—Sixteen members of a family with sinus bradycardia were evaluated. Evaluation included a clinical questionnaire, 12-lead ECGs, Holter monitoring, echocardiography, and treadmill exercise testing. Eight family members (5 males) were classified as affected. All affected family members were asymptomatic with normal exercise capacity during long-term follow-up. Electrophysiological testing performed on 2 affected family members confirmed significant isolated sinus node dysfunction. Segregation analysis suggested autosomal-dominant inheritance. Direct sequencing of the exons encoding HCN4 revealed a missense mutation, G480R, in the ion channel pore domain in all affected family members. Function analysis, including expression of HCN4 wild-type and G480R inXenopusoocytes and human embryonic kidney 293 cells, revealed that mutant channels were activated at more negative voltages compared with wild-type channels. Synthesis and expression of the wild-type and mutant HCN4 channel on the plasma membrane tested in human embryonic kidney 293 cells using biotinylation and Western blot analysis demonstrated a reduction in synthesis and a trafficking defect in mutant compared with wild-type channels.

Conclusions—We describe an inherited, autosomal-dominant form of sinus node dysfunction caused by a missense mutation in the HCN4 ion channel pore. Despite its critical location, this mutation carries a favorable prognosis without the need for pacemaker implantation during long-term follow-up.
Splanchnic Circulation Is a Critical Neural Target in Angiotensin II Salt Hypertension in Rats
Authors: King Andrew J. , Osborn John W. , Fink Gregory D.
Published: July 2007

Chronic angiotensin II (Ang II) infusion, in rats fed high salt, engages the sympathetic nervous system to increase venomotor tone. The splanchnic sympathetic nervous system is the most important regulator of venous tone, indicating that splanchnic sympathetic nervous system activity may be increased in Ang II salt hypertension. We hypothesized that celiac ganglionectomy (CGx), to selectively disrupt sympathetic innervation to the splanchnic circulation, would attenuate arterial pressure (AP), and venous tone increases in Ang II salt hypertension. Rats fed 2% or 0.4% NaCl were instrumented to allow AP measurement by radiotelemetry at the same time as surgical CGx or sham operation. Ang II was delivered by minipump (150 ng/kg per minute) for 14 days. CGx reduced AP independent of salt diet during control. CGx markedly attenuated Ang II hypertension in rats on 2% NaCl but had little effect in rats fed 0.4% NaCl. To test the possibility that CGx exerted its effects via renal denervation, rats were subjected to the same protocol but received selective bilateral renal denervation. Renal denervation decreased AP during control but had no protective effect on Ang II hypertension and actually tended to exacerbate the pressor response. Finally, separate groups of rats underwent CGx or sham operation and were instrumented to allow repeated measures of mean circulatory filling pressure, an index of venous tone. In addition to attenuating Ang II salt hypertension, CGx completely prevented Ang II salt-induced increases in mean circulatory filling pressure and substantially attenuated depressor responses to acute ganglion blockade. We conclude that, in the presence of high salt, Ang II activates the splanchnic sympathetic nervous system to increase venomotor tone and AP.
Pregnant Rats Treated With a Serotonin Precursor Have Reduced Fetal Weight and Lower Plasma Volume and Kallikrein Levels
Authors: Salas Sofía P. , Giacaman Andrea , Romero William , Downey Patricio , Aranda Eduardo , Mezzano Diego , Vío Carlos P.
Published: July 2007

Pregnant women with preeclampsia have increased serotonin levels, suggesting a possible role of this amine in abnormal pregnancy. With the hypothesis that an increase in serotonin would reduce volume expansion and cause fetal growth restriction, we evaluated the maternal and fetal effects of the administration of the serotonin precursor 5-hidroxytryptophan (5-HTP) to Sprague-Dawley rats. At pregnancy day 13 (n=19) or in random cycle nonpregnant rats (n=10), animals were assigned to a single injection of 5-HTP (100 mg/kg IP) or to a control group. Animals were studied at day 21, after overnight urinary collection. Additional pregnant rats received ketanserin (1 mg/kg), a 5-HT
2
receptor antagonist, 1 hour before 5-HTP injection. In pregnant rats, 5-HTP lowered plasma volume (control: 22±1.1; 5-HTP: 17±0.7 mL;
P
<0.001) and creatinine clearance, whereas serum creatinine and urinary protein excretion were increased; no changes were observed in nonpregnant rats. Systolic blood pressure did not change significantly. Urinary kallikrein activity and plasma aldosterone levels decreased only in pregnant animals. Fetal (control: 5.5±0.1; 5-HTP: 4.2±0.2 g;
P
<0.001) and placental weights were reduced. In nonpregnant and pregnant animals, 5-HTP caused profound renal morphological alterations and decreased kallikrein immunostaining. Preadministration of ketanserin abolished all of the changes associated with the use of 5-HTP. These data indicate that the administration of a serotonin precursor to pregnant rats limits plasma volume expansion and fetal growth via 5-HT
2
receptors, suggesting a possible role for serotonin in abnormal pregnancy. We postulate that an increased vascular resistance, both at the placental and renal levels, mediates these effects.
Flashpoint Austria: The Communist-Inspired Strikes of 1950
Authors: Williams Warren
Published: July 2007

Austria is frequently overlooked by Cold War historians, but this small landlocked country was the site of a number of East-West confrontations during the decade of occupation by the United States, Britain, France, and the Soviet Union from 1945 to 1955. This article focuses on two of those incidents. In September and October 1950, Austria's Communist Party, supported by Soviet occupation forces, triggered a series of violent demonstrations throughout the country, ostensibly objecting to a new Wage and Price Agreement. Whether these strikes were part of a planned attempt to overthrow the central government is a question still debated. The article assesses the different views on this matter and the evidence available.
Perspectives on Resistance with the People
Authors: van Dijk Ruud , Grieder Peter E.
Published: July 2007

Gary Bruce's volume in the Harvard Cold War Studies Book Series, Resistance with the People: Repression and Resistance in Eastern Germany, 1945–1955, provides an overview of the East German state security apparatus (Stasi) from the mid-1940s, when secret police organs were set up in eastern Germany by the Soviet occupation forces, through the mid-1950s, when the size of the Stasi sharply increased, allowing it to become a massive surveillance and repressive apparatus. Bruce examines the origins of the Stasi, the role of the state security organs in the outbreak and suppression of the East German uprising of June 1953, and the subsequent evolution of the Stasi under Walter Ulbricht, who removed his rivals from the state security apparatus and then reestablished it as a separate ministry responsible for “combatting all internal and external enemies” of the Communist regime. Two prominent experts on East German history offer their perspectives on Bruce's book and the role of popular resistance under Communist rule.
A Multichip Neuromorphic System for Spike-Based Visual Information Processing
Authors: Vogelstein R. Jacob , Mallik Udayan , Culurciello Eugenio , Cauwenberghs Gert , Etienne-Cummings Ralph
Published: July 2007

We present a multichip, mixed-signal VLSI system for spike-based vision processing. The system consists of an 80 × 60 pixel neuromorphic retina and a 4800 neuron silicon cortex with 4,194,304 synapses. Its functionality is illustrated with experimental data on multiple components of an attention-based hierarchical model of cortical object recognition, including feature coding, salience detection, and foveation. This model exploits arbitrary and reconfigurable connectivity between cells in the multichip architecture, achieved by asynchronously routing neural spike events within and between chips according to a memory-based look-up table. Synaptic parameters, including conductance and reversal potential, are also stored in memory and are used to dynamically configure synapse circuits within the silicon neurons.
Variable Timescales of Repeated Spike Patterns in Synfire Chain with Mexican-Hat Connectivity
Authors: Hamaguchi Kosuke , Okada Masato , Aihara Kazuyuki
Published: July 2007

Repetitions of precise spike patterns observed both in vivo and in vitro have been reported for more than a decade. Studies on the spike volley (a pulse packet) propagating through a homogeneous feedforward network have demonstrated its capability of generating spike patterns with millisecond fidelity. This model is called the synfire chain and suggests a possible mechanism for generating repeated spike patterns (RSPs). The propagation speed of the pulse packet determines the temporal property of RSPs. However, the relationship between propagation speed and network structure is not well understood. We studied a feedforward network with Mexican-hat connectivity by using the leaky integrate-and-fire neuron model and analyzed the network dynamics with the Fokker-Planck equation. We examined the effect of the spatial pattern of pulse packets on RSPs in the network with multistability. Pulse packets can take spatially uniform or localized shapes in a multistable regime, and they propagate with different speeds. These distinct pulse packets generate RSPs with different timescales, but the order of spikes and the ratios between interspike intervals are preserved. This result indicates that the RSPs can be transformed into the same template pattern through the expanding or contracting operation of the timescale.
Self-Organizing Maps with Asymmetric Neighborhood Function
Authors: Aoki Takaaki , Aoyagi Toshio
Published: July 2007

The self-organizing map (SOM) is an unsupervised learning method as well as a type of nonlinear principal component analysis that forms a topologically ordered mapping from the high-dimensional data space to a low-dimensional representation space. It has recently found wide applications in such areas as visualization, classification, and mining of various data. However, when the data sets to be processed are very large, a copious amount of time is often required to train the map, which seems to restrict the range of putative applications. One of the major culprits for this slow ordering time is that a kind of topological defect (e.g., a kink in one dimension or a twist in two dimensions) gets created in the map during training. Once such a defect appears in the map during training, the ordered map cannot be obtained until the defect is eliminated, for which the number of iterations required is typically several times larger than in the absence of the defect. In order to overcome this weakness, we propose that an asymmetric neighborhood function be used for the SOM algorithm. Compared with the commonly used symmetric neighborhood function, we found that an asymmetric neighborhood function accelerates the ordering process of the SOM algorithm, though this asymmetry tends to distort the generated ordered map. We demonstrate that the distortion of the map can be suppressed by improving the asymmetric neighborhood function SOM algorithm. The number of learning steps required for perfect ordering in the case of the one-dimensional SOM is numerically shown to be reduced from O(N3) to O(N2) with an asymmetric neighborhood function, even when the improved algorithm is used to get the final map without distortion.
Parametric Embedding for Class Visualization
Authors: Iwata Tomoharu , Saito Kazumi , Ueda Naonori , Stromsten Sean , Griffiths Thomas L. , Tenenbaum Joshua B.
Published: July 2007

We propose a new method, parametric embedding (PE), that embeds objects with the class structure into a low-dimensional visualization space. PE takes as input a set of class conditional probabilities for given data points and tries to preserve the structure in an embedding space by minimizing a sum of Kullback-Leibler divergences, under the assumption that samples are generated by a gaussian mixture with equal covariances in the embedding space. PE has many potential uses depending on the source of the input data, providing insight into the classifier's behavior in supervised, semisupervised, and unsupervised settings. The PE algorithm has a computational advantage over conventional embedding methods based on pairwise object relations since its complexity scales with the product of the number of objects and the number of classes. We demonstrate PE by visualizing supervised categorization of Web pages, semisupervised categorization of digits, and the relations of words and latent topics found by an unsupervised algorithm, latent Dirichlet allocation.
MISEP Method for Postnonlinear Blind Source Separation
Authors: Zheng Chun-Hou , Huang De-Shuang , Li Kang , Irwin George , Sun Zhan-Li
Published: July 2007

In this letter, a standard postnonlinear blind source separation algorithm is proposed, based on the MISEP method, which is widely used in linear and nonlinear independent component analysis. To best suit a wide class of postnonlinear mixtures, we adapt the MISEP method to incorporate a priori information of the mixtures. In particular, a group of three-layered perceptrons and a linear network are used as the unmixing system to separate sources in the postnonlinear mixtures, and another group of three-layered perceptron is used as the auxiliary network. The learning algorithm for the unmixing system is then obtained by maximizing the output entropy of the auxiliary network. The proposed method is applied to postnonlinear blind source separation of both simulation signals and real speech signals, and the experimental results demonstrate its effectiveness and efficiency in comparison with existing methods.
The Law of the Sea Convention and the Northwest Passage
Authors: Kraska James
Published: July 2007

Concern over the loss of sea ice has renewed discussions over the legal status of the Arctic and sub-Arctic transcontinental maritime route connecting the Atlantic and the Pacific, referred to as the "Northwest Passage." Over the last thirty years, Canada has maintained that the waters of the Passage are some combination of internal waters or territorial seas. Applying the rules of international law, as reflected in the 1982 United Nations Law of the Sea Convention, suggests that the Passage is a strait used for international navigation. Expressing concerns over maritime safety and security, recognition of northern sovereignty, and protection of the fragile Arctic environment, Canada has sought to exercise greater authority over the Passage. This article suggests that Canada can best achieve widespread global support for managing its maritime Arctic by acknowledging that the passage constitutes an international strait and then working through the International Maritime Organization to develop a comprehensive package of internationally accepted regulations.
Minding the Gap: The Australia–East Timor Treaty on Certain Maritime Arrangements in the Timor Sea (CMATS)
Authors: Schofield Clive
Published: July 2007

The intertwined issues of the delimitation of maritime boundaries and the division of the resources, particularly petroleum resources, of the Timor Sea have served as a persistent irritant in bilateral relations between Australia and East Timor since the latter's independence in 2002. In 2003 an International Unitization Agreement for the Greater Sunrise complex of fields was signed. This was followed by the conclusion in 2006 of the Treaty on Certain Maritime Arrangements in the Timor Sea. The subsequent entry into force of these agreements, in February 2007, appears to resolve this contentious dispute, at least for the foreseeable future. This article explores the background to the dispute and positions of the parties, traces the progress of negotiations towards its interim resolution and then assesses the agreements themselves. It is concluded that while the agreements are, on balance, somewhat more favourable to Australia than to East Timor, they can still be viewed as beneficial to both parties.
Law of the Sea Aspects of the Negotiations in the WTO to Harmonise Rules of Origin
Authors: Serdy Andrew
Published: July 2007

A major source of controversy in the protracted Rules of Origin negotiations at the World Trade Organization is the origin to be ascribed to fish taken from the exclusive economic zone. Participants' positions are polarised between views recalling the old great divide between coastal States and distant-water fishing States, one camp seemingly oblivious to the past 50 years' developments in international fisheries law, the other adhering rigidly to a position elevating origin to the status of one of the coastal State's sovereign rights, even though practical considerations make such a rule unworkable. It is concluded that the rules of origin issue does not lend itself to use as a proxy vehicle for advancing legal and policy interests in international fisheries, and a compromise solution is offered that may enhance international fisheries commissions' authority in managing their species. Some problematic aspects of the much less controversial origin rules on minerals recovered from the deep seabed are also considered.
Elastoviscoplastic Model and Concept of Slip
Authors: Nikitin I.
Published: July 2007

The model of elastoviscoplastic medium is based on the concept of slip proposed by Batdorf and Budiansky. The conditions of slip on a slip plane take into account the dependence of tangential stresses on slip velocity. But when the viscosity is low, they are almost similar to the dry friction conditions. Under some assumptions we succeeded in integrating the plastic shear rates over all possible slip planes in case of arbitrary three‐dimensional stress state and obtained an expression for the plastic strain rate tensor.
Seismic Response of R‐C Frame Structure Controlled by Ved
Authors: Weibing Hu , Xing Chen , Jian He
Published: July 2007

Based on the character of R‐C frame, the calculation formula of VED is derived from the sub‐structure plan of lateral resistant force, the definition of equivalent stiffness matrix and equivalent additional viscoelastic force vector of VED is given and the seismic dynamic equation of R‐C frame controlled by VED is set up, the viscoelastic additional force vector of VED should be considered as outside load of structure and be calculated through the pseudo‐loading method, the programs of calculating the dynamic characteristic, calculating the elastic seismic response and calculating the elastic‐plastic seismic response of R‐C frame controlled by VED are compiled. Through the calculation of a inclined crossed R‐C frame, the results show that VED is effective in controlling the seismic response of frame and the pseudo‐loading method is reliable in the calculation.
Optimization of Load Uniformity for Triangular Tube Using Non‐Linear Programming
Authors: Sun J. , Ekwaro‐Osire S.
Published: July 2007

The paper focuses on two topics, optimizing the proposed triangular tube for crashworthiness and solving a non‐linear programming problem by a “mapping” technique, which the condition of Lagrange Multiplier Theorem is violated within the feasible region. The purpose of studying optimized triangular tubes is to prepare them for redesigning vehicle bumpers. The dimension optimization of triangular tube is carried out for its thickness and lateral length, based on the accomplished shape optimization under an impact. The load uniformity is taken as the objective function, which is defined as the ratio of maximum peak force and means crushing force. Meanwhile the mean crushing force and absorbed energy are treated as constraints. Based on FEA analysis, the regression functions for load uniformity, mean crushing force, and absorbed energy are formulated by RSM. The result has shown that triangular tube possesses an optimization region, under which the better‐integrated property can be achieved to supply a more safety environment for vehicular occupants.
The Definition of Linear Frequencies of Bending Vibrations of Magnetoelastic Cylindrical Shell by Exact Space Treatment
Authors: Bagdoev A G , Vardanyan A G , Vardanyan S V
Published: July 2007

The free bending vibrations of magnetoelastic cylindrical shell in axial magnetic field are considered. The solution is carried out by developed for elastic plates by V. Novatsky exact space method which is applied by ourselves to solution of magnetoelasticity equations without any hypothesis. Obtained by means of exact solution dispersion relation between frequency and wave number of vibration of shell is investigated numerically and obtained tables for real part of frequency with respect to wave, number and field are compared with those obtained by averaged treatment based on Kirkhoff hypothesis. The results are quite different which shows that in contrast to the elastic bending vibrations for magnetoelastic plates and shells mentioned hypothesis are not applicable.
Analysis of Adhesion Stresses for the Design of RC Beam Bonded with Thin Composite Plate
Authors: Ait Ameur Meziane M. , Benyoucef S. , Tounsi A. , Adda Bedia E.A.
Published: July 2007

Fibre‐reinforced plastic (FRP) materials have been recognised as new innovative materials for concrete rehabilitation and retrofit. Since concrete is poor in tension, a beam without any form of reinforcement will fail when subjected to a relatively small tensile load. Therefore, the bonding of FRP plate to reinforced concrete (RC) structure is an effective solution to increase its overall strength. In such plated beams, tensile forces develop in the bonded plate and these have to be transferred to the original beam via interfacial shear and normal stresses. Consequently, the debonding of FRP plates bonded to reinforced concrete beams is believed to be initiated by the stress concentration in the adhesive layer. Accurate predictions of the interfacial stresses are prerequisite for designing against debonding failures. In the present analysis, a simple theoretical model to estimate shear and normal stresses is proposed, including the variation in FRP plate fibre orientation. The solution shows significant shear and normal stresses concentration at the plates end. A parametrical study is carried out to show the effects of some design variables, e.g., thickness of adhesive layer and FRP plate, and the distance from support to cut ‐ off end of bonded plates.
Optimizing the Operating Conditions of a Molybdenum Target Total Reflection X‐Ray Fluorescence (TXRF) Spectrometer Using a Computer Model
Authors: Adejumo O.O. , Ojo J.O.
Published: July 2007

The results of trial experiments carried out with a computer simulation model of total reflection X‐ray fluorescence, TXRF system to determine optimum conditions for detecting certain elements of interest under various analytical conditions in a given ten‐element standard sample is presented in this paper. Results of these trial experiments show that the detectability of elements improved with increasing applied voltages up to about 43kV (for a Molybdenum anode TXRF spectrometer) and atomic number of elements. Variation of geometry such as the glancing incidence angle of the excitation beam reflected slight increase in minimum detection limit, MDL values as the angle of incidence is reduced from an optimum value of 1.6mradian to 1.0mradian. The nature of the sample support was observed to affect the detectability of the elements as good detection limits were obtained if gold is used as sample holder..
EI Extended Model and the Fear of Ecological Fallacy
Authors: Baodong Liu
Published: July 2007

Most existing models of ecological inference are based on the assumption that there is no aggregation bias. Few studies have focused on how to correct/ model aggregation bias. This article takes advantage of a unique opportunity to compare the controversial ecological inference methods by using aggregate as well as individual-level data from an actual election. Furthermore, the true quantities of interest are also available, which guarantees the accuracy of the empirical tests. Our mean squared error analyses show that King's Ecological Inference (EI) basic model does not always outperform the traditional ecological regression and neighborhood methods when aggregation bias does exist. However, using an appropriate covariate in the King's EI extended model to correct the aggregation bias problem can drastically improve the estimation accuracy at both the precinct and district levels. This article also makes suggestions on how to use a covariate in a King's extended model.
Linked Markov Sources
Authors: Elzinga Cees H. , Hoogendoorn Adriaan W. , Dijkstra Wil
Published: July 2007

Many social processes are adaptive in the sense that the process changes as a result of previous outcomes. Data on such processes may come in the form of categorical time series. First, the authors propose a class of Markov Source models that embody such adaptation. Second, the authors discuss new methods to evaluate the fit of such models. Third, the authors apply these models and methods to data on a social process that is a preeminent example of an adaptive process: (encoded) conversation as arises in structured interviews.
Latent Variable Models Under Misspecification: Two-Stage Least Squares (2SLS) and Maximum Likelihood (ML) Estimators
Authors: Bollen Kenneth A. , Kirby James B. , Curran Patrick J. , Paxton Pamela M. , Chen Feinian
Published: July 2007

This article compares maximum likelihood (ML) estimation to three variants of two-stage least squares (2SLS) estimation in structural equation models. The authors use models that are both correctly and incorrectly specified. Simulated data are used to assess bias, efficiency, and accuracy of hypothesis tests. Generally, 2SLS with reduced sets of instrumental variables performs similarly to ML when models are correctly specified. Under correct specification, both estimators have little bias except at the smallest sample sizes and are approximately equally efficient. As predicted, when models are incorrectly specified, 2SLS generally performs better, with less bias and more accurate hypothesis tests. Unless a researcher has tremendous confidence in the correctness of his or her model, these results suggest that a 2SLS estimator should be considered.
Predicting Differences in the Perceived Relevance of Crime's Costs and Benefits in a Test of Rational Choice Theory
Authors: Bouffard Jeffrey A.
Published: July 2007

Previous hypothetical scenario tests of rational choice theory have presented all participants with the same set of consequences, implicitly assuming that these consequences would be relevant for each individual. Recent research demonstrates that those researcher-presented consequences do not accurately reflect those considered by study participants and that there is individual variation in the relevance of various consequences. Despite this and some theoretical propositions that such differences should exist, little empirical research has explored the possibility of predicting such variation. This study allows participants to develop their own set of relevant consequences for three hypothetical offenses and examines how several demographic and theoretical variables impact those consequences' relevance. Exploratory results suggest individual factors impact the perceived relevance of several cost and benefit types, even among a relatively homogenous sample of college students. Implications for future tests of rational choice theory, as well as policy implications are discussed.
A Classification of Sexual Homicide Against Men
Authors: Beauregard Eric , Proulx Jean
Published: July 2007

The observation and description of 10 cases of sexual murderers of adult male victims lead to the identification of significant differences between this type of sexual murderer and sexual murderers of adult female victims. A classification is proposed based on the description of the entire criminal event. Three distinctive types are identified: (a) the avenger, (b) the sexual predator, and (c) the nonsexual predator. The motivation and the characteristics of the entire criminal event, which includes the study of the offender, the victim, and the context of the crime are discussed for the three types.
Juvenile Sex-Only and Sex-Plus Offenders
Authors: van Wijk A. Ph. , Mali S. R. F. , Bullens R. A. R.
Published: July 2007

In this study, research was done on the criminal profiles of a large group of juvenile sex-only and sex-plus (sex and other offenses) delinquents ( N = 4,430) in the Netherlands. Use was made of information from police records. Results show that sex-plus offenders start their careers earlier, that more of these offenders are of non-Dutch origin, that they commit more crimes, and will partly continue their criminal career after their adolescence. Juvenile sex-only offenders rarely go on committing crimes. In sex-plus offenders, sexual crimes play only a minor role in their total crime repertory. As time goes by, their criminal career will develop into the direction of property crimes. Finally, the implications and limitations of this study will be discussed.
Joint Analysis of Multiple Categorical Dependent Variables in Organizational Research
Authors: Westfall Peter , Hoffman James J. , Jun Xia
Published: July 2007

A model for analyzing multiple categorical dependent variables is presented and developed for use in organizational research. A primary example occurs in the foreign market entry literature, in which choice of ownership (majority, equal, or minority) and function (acquisition or joint venture) are simultaneously endogenous; only separate univariate ownership-based and function-based choice models are considered in the literature. Another example is in the comparison of gender and race across organizational units, controlling for confounders such as experience and qualification. Subsuming univariate categorical dependent variables as a special case, the model unifies existing organizational research methods, mitigates bias associated with univariate methods, provides more powerful testing methods, and provides a flexible modeling framework that allows hypotheses to be modeled and tested that are not possible with univariate models. Standard software may be used for estimation and testing; examples are given.
Growth Mixture Modeling
Authors: Mo Wang  , Bodner Todd E.
Published: July 2007

An important limitation of conventional latent-growth modeling (LGM) is that it assumes that all individuals are drawn from one or more observed populations. However, in many applied-research situations, unobserved subpopulations may exist, and their different latent trajectories may be the focus of research to test theory or to resolve inconsistent prior research findings. Conventional LGM does not help to identify and predict these unobserved subpopulations. This article introduces the growth-mixture modeling (GMM) method for these purposes. Given that GMM handles longitudinal data (i.e., nesting of time observations within individuals) and identifies unobserved subpopulations (i.e., the nesting of individuals within latent classes), GMM can be construed as a multilevel modeling technique. The modeling procedure of GMM is illustrated on a simulated data set. Steps in the modeling process are highlighted and limitations, cautions, recommendations, and extensions of using GMM are discussed. Technical references for additional information are noted throughout.
Prospective Case Study Design
Authors: Bitektine Alex
Published: July 2007

The article advances a prospective case study design in social sciences as an alternative to traditional post hoc case study research in deductive theory testing. It is argued that some limitations of post hoc qualitative methods in deductive theory testing can be alleviated by using a prospective case study design, where researchers formulate a set of theory-based hypotheses in respect to the evolution of an ongoing social process and then test these hypotheses at a predetermined follow-up time in the future by comparing them with the observed outcomes using pattern matching or a similar technique. Some challenges of conducting prospective research in social sciences are discussed. An illustration of the application of this method in deductive testing of two competing theories is provided.