bluuebunny/crossref_metadata_2025 huggingface dataset:
Memory Retention and Spike-Timing-Dependent Plasticity
Authors: Billings Guy , van Rossum Mark C. W.
Published: March 2009

Memory systems should be plastic to allow for learning; however, they should also retain earlier memories. Here we explore how synaptic weights and memories are retained in models of single neurons and networks equipped with spike-timing-dependent plasticity. We show that for single neuron models, the precise learning rule has a strong effect on the memory retention time. In particular, a soft-bound, weight-dependent learning rule has a very short retention time as compared with a learning rule that is independent of the synaptic weights. Next, we explore how the retention time is reflected in receptive field stability in networks. As in the single neuron case, the weight-dependent learning rule yields less stable receptive fields than a weight-independent rule. However, receptive fields stabilize in the presence of sufficient lateral inhibition, demonstrating that plasticity in networks can be regulated by inhibition and suggesting a novel role for inhibition in neural circuits.
Detecting Precipitating Clouds over Snow and Ice Using a Multiple Sensors Approach
Authors: Todini G. , Rizzi R. , Todini E.
Published: March 2009

This work discusses a snowfall detection approach for high-latitude regions that is based on a combination of passive sensors to discriminate between snowing and nonsnowing areas. Two different techniques have been developed to compute the probability of detecting a snowing event. The first technique is based on a logistic distribution to represent the probability of snowfall given the predictors; the second is a Bayesian technique not requiring any hypothesis as to the shape of the probabilistic model. The spaceborne Advanced Microwave Sounding Units A and B (on NOAA-16) and the Moderate Resolution Imaging Spectroradiometer (on Aqua) have been collocated and used for the estimation. Products from the spaceborne cloud-profiling radar on CloudSat are used as truth to calibrate and validate the proposed approaches. A comparison with a well-known rain-rate model, developed by the Remote Sensing and Estimation Group of the Massachusetts Institute of Technology, is also presented, showing that both proposed methods discriminate snowing and nonsnowing condition over the polar regions, reducing by at least 30% the false alarms while considerably increasing the probability of detection.
Changes of Glaciers and Climate in Northwestern North America during the Late Twentieth Century
Authors: Arendt Anthony , Walsh John , Harrison William
Published: March 2009

About 75% of 46 glaciers measured using repeat airborne altimetry in Alaska and northwestern Canada have been losing mass at an increasing rate from the mid-1990s to the middle of the first decade of the twenty-first century, relative to an earlier period beginning in the 1950s–70s. The remaining glaciers have been either gaining mass during the more recent period or continuing to lose mass, but at a decreasing rate. Temperature and precipitation data at 67 climate stations were examined to explain these changes. Nearly all significant changes in winter (October–April) and summer (May–September) air temperatures were positive (2.0° ± 0.8° and 1.0° ± 0.4°C) between 1950 and 2002, and all seasonally averaged values of freezing level heights (FLH) increased during the same time period. A small increase in precipitation was observed, but these changes were significant at only 17% of the stations. Regional glacier changes, modeled using mass balance sensitivities and climate station temperature and precipitation changes, agreed with observations to within the limits of reported errors. Seasonal variations in accumulation resulted in large uncertainties in the recent period mass variations. In nearly all regions, increasing summer temperatures accounted for most of the glacier mass losses. FLH variations show that the maritime glacier systems are more sensitive to variations in the mean position of the winter FLH than interior regions, suggesting that strong winter warming has affected these regions in addition to the summer changes. These measurements augment the increasingly strong evidence of late twentieth-century climate change in northwestern North America.
The Role of Gender in the Racial and Ethnic Socialization of African American Adolescents
Authors: Brown Tiffany L. , Linver Miriam R. , Evans Melanie
Published: March 2009

Scholars in the field of African American family studies recognize the influence of gender on socialization. However, few studies investigate how gender influences the racial and ethnic socialization of African American youth. To examine the role of gender (both caregiver and adolescent) in socialization practices, data were obtained from 218 African American adolescents attending a public high school in the northeastern United States. Participants reported on the socialization messages provided by their caregivers by completing the Adolescent Racial and Ethnic Socialization Scale (ARESS). The ARESS is a newly developed measure of racial socialization and ethnic socialization, which assesses these constructs as distinct multidimensional processes. A series of ANCOVAs revealed that male and female caregivers differ in their approaches to racial and ethnic socialization. Findings suggest that caregivers engage in more socialization with female adolescents and raise questions about how gender differences may be related to African American youth development.
Toward a Neoliberal Europe?
Authors: Frericks Patricia , Maier Robert , de Graaf Willibrord
Published: March 2009

The authors argue that starting from a welfare state, based on specific assumptions regarding generations, gender, and labor markets, two extreme directions of possible development—toward privatization and toward solidarity—are currently being taken. European welfare reforms transfer many services, needs, and responsibilities to the market, examples of a neoliberal tendency. However, there is also a contrasting and striking development toward solidarity, based on extensive regulatory policies, examples of a neoetatistic tendency. Focusing on pension reforms, the authors analyze this twofold development which the authors observe in reform measures and discourses; it redefines social rights, and therefore transforms social identity and citizenship.
Executive Incentive Schemes in Initial Public Offerings: The Effects of Multiple-Agency Conflicts and Corporate Governance
Authors: Allcock Deborah , Filatotchev Igor
Published: March 2009

Combining a behavioral agency perspective with research on multiple-agency conflicts, this article examines factors affecting the implementation of equity-based incentive schemes in initial public offerings (IPOs). With a unique sample of U.K. IPO companies between the years 1998 and 2002, it shows that conditional (performance-related) incentive schemes are negatively associated with share ownership and board power of the IPO’s founding directors. However, the retained ownership of venture capital firms is positively associated with the probability of conditional incentive schemes. Board independence weakly effects on the toughness of executive compensation. The article’s interesting findings suggest a number of avenues for a future analysis of the governance development process in threshold firms.
Pygmalion and Employee Learning: The Role of Leader Behaviors
Authors: Bezuijen Xander M. , van den Berg Peter T. , van Dam Karen , Thierry Henk
Published: March 2009

The aim of this study was to investigate which leader behaviors mediate the relationship between leader expectations and employee engagement in learning activities. Based on Rosenthal’s Pygmalion model, five potential mediators of the Pygmalion effect were distinguished: leader—member exchange relationship, goal setting (i.e., goal specificity, goal difficulty), providing learning opportunities, and feedback. Data from 904 manager—subordinate dyads in six organizations showed that leader expectations were related to employee engagement in learning activities. Goal specificity, goal difficulty, and providing learning opportunities proved to be mediators. These findings suggest that goal setting lies at the heart of the Pygmalion effect.
Organization-Level Mentoring and Organizational Performance Within Substance Abuse Centers
Authors: Allen Tammy D. , Smith Mark Alan , Mael Fred A. , Gavan O'Shea Patrick , Eby Lillian T.
Published: March 2009

Individual benefits to those who have been mentored are well documented. The present study demonstrates that organization-level mentoring relates to overall organizational performance. In a study of 589 employees of 39 substance abuse treatment agencies, the authors found that agencies with a greater proportion of mentored employees also reported greater overall agency performance. Organization-level mentoring also related to organization-level job satisfaction, organization-level organizational citizenship behavior, and organization-level learning. Results provide justification for organizational investment of time and resources into efforts designed to facilitate mentoring, as well as support the notion that mentoring may provide a competitive advantage to organizations.
Commuting Trends in U.S. Cities in the 1990s
Authors: Lee Bumsoo , Gordon Peter , Richardson Harry W. , Moore James E.
Published: March 2009

This article attempts to explain the increase in commuting times in the 1990s after decades of stability. Although traditional explanations, for example both demographic variables (population growth and densities) and transportation variables (e.g. road capacity and transit use), pass the statistical significance tests, their overall impact was small. Instead, the article argues for the importance of strong income growth in the late 1990s, not least because it was associated with an increase in non-work vehicle miles traveled; these affect commuting times because many non-work trips take place in peak hours.
Pharyngeal-Cervical-Brachial Variant of Pediatric Guillain-Barré Syndrome With Antecedent Acute Hepatitis A Virus Infection
Authors: Thapa Rajoo , Biswas Biawajit , Mallick Debkrishna , Mukherjee Swapan
Published: March 2009

Pharyngeal-cervical-brachial weakness is considered a variant of Guillain-Barré syndrome with limited oropharyngeal, neck, and upper limb muscle involvement. The authors report on a 7-year-old boy, who developed pharyngeal-cervical-brachial type of Guillain-Barré syndrome following an antecedent episode of acute hepatitis A virus infection, 2 weeks prior to admission. The presentation was characterized by acute onset dysphagia, loss of head control, and bilateral arm weakness. The diagnosis was confirmed by acute motor axonal changes in the arm and albuminocytologic dissociation of the cerebrospinal fluid. The child was treated with intravenous immunoglobulin, which resulted in gradual improvement over 3 weeks. Documented instances of this form of Guillain-Barré syndrome remain rare in the pediatric age group, with none existing following antecedent hepatitis A virus infection. The authors emphasize that acute hepatitis A virus infection be included in the triggers responsible for Guillain-Barré syndrome in children.
Clinical and Genetic Studies in a Chinese Family With Giant Axonal Neuropathy
Authors: Zhang Li-Ping , Zou Li-Ping
Published: March 2009

The objective of the study was to investigate a girl with giant axonal neuropathy and detect the mutation of GAN gene in her family. The encoding exons of GAN gene were amplified from genomic DNA of the proband and her parents by polymerase chain reaction and directly sequenced after purification. The proband manifested typical neurological symptoms and pathological abnormalities. The case had 2 heterozygous missense mutations in GAN gene: 1. c. 224 T>A in exon 2, her mother was a heterozygote of this mutation and had normal phenotype; 2. c.1634G>A in exon 10, and her father was a heterozygote of this mutation and had normal phenotype. Both of the mutations caused amino acid changes in the gigaxonin protein. In this family, missense mutation of c.224 T>A and missense mutation of c.1634G>A in GAN gene caused the phenotype of giant axonal neuropathy in the proband. Her parents are heterozygotes of the disease without symptoms.
Practice Parameters in Child Neurology: Do Pediatricians Use Them?
Authors: Bale James F. , Caplin Deirdre A. , Bruse Jaime D. , Folland David
Published: March 2009

We assessed pediatrician awareness of the parameter ‘‘Evaluating the first non-febrile seizure in children’’ and how the concepts of this parameter were incorporated into practice. Although most reported caring for children with seizures, 60% were not aware of the practice parameter. When given the clinical scenario of an otherwise healthy 8-year-old child with a first, unprovoked seizure, management was variable. Most (83%) would obtain an electroencephalography, and many (58%) would order an imaging study, usually a magnetic resonance imaging. However, most were also likely to order laboratory studies that were not indicated given the scenario and the practice parameter. This pilot study suggests that pediatricians may not be aware of this practice parameter and many may not be incorporating evidence-based recommendations regarding the evaluation of children with new-onset seizures.
A Visigoth System
Authors: Conti Norman
Published: March 2009

This article documents the process by which a police academy staff generates an interaction order of obedience to authority during recruit training. Specifically, it examines the formal pattern of face-to-face interaction that recruits are expected to embrace before they can engage the larger occupational culture. The staff utilizes a dialectical method akin to Braithwaite's model of reintegrative shaming in which recruits are simultaneously degraded for what are defined as highly stigmatic civilian characteristics and offered a status elevation for the excision of these problematic attributes. Subscription to or deviance from established rituals is taken as evidence of personal character and assists in driving recruits through a moral career, in which they can evolve to an idealized status of police officer.
Making Sense of the Social Forum
Authors: Nordvall Henrik
Published: March 2009

The worldwide emergence of Social Forums (SF), originating from Porto Alegre (Brazil) in 2001, is a key element in the movement for global justice. A growing body of literature on the forums concerns its function as a transnational venue for civil society and a global symbol for resistance against neoliberalism. However, little empirical research is carried out on the local meanings of the widespread SFs. This article reports on a case study on the organizational process of a local forum in a Swedish town. The analysis focuses on intracoalitional interaction among activists from the labor movement, Attac, and a local cultural institution. The importance of considering local framing processes and the often-neglected influence of fashion when studying the emergence of SFs is emphasized. Findings show how the dichotomy the Old versus the New became crucial in the framing process. Framed as a novelty contrasted with “old” socialist values, the SF was rejected by the labor movement activists as just another expression of a contemporary neoliberal trend of depoliticization. Implications for the study of the social forum phenomenon are discussed.
Treatment Considerations for Diabetes: A Pharmacist’s Guide to Improving Care in the Elderly
Authors: Nicholas Amy S. , Nadeau Daniel A. , Johnson and Carrie L.
Published: March 2009

The management of diabetes in elderly patients has many nuances that are important to the pharmacist, regardless of his or her practice setting. General guidelines and treatment modalities applied to the younger population cannot necessarily be applied to the elderly population and in most cases, should be tailored to meet their needs. The purpose of this article is to gain a better understanding of the complex nature of diabetes and management in the elderly by (1) reviewing the pathogenesis and pathophysiology of diabetes in the patients, (2) understanding complications and geriatric syndromes that may affect management of diabetes, (3) becoming familiar with nationally accepted diabetes care guidelines in the elderly, (4) reviewing recent literature pertaining to management of diabetes, and (5) reviewing medications (including newer agents) to treat diabetes in the elderly.
Muscle Gains and Emotional Strains: Conflicting Experiences of Change Among Overweight Women Participating in an Exercise Intervention Program
Authors: Sabiston Catherine M. , McDonough Meghan H. , Sedgwick Whitney A. , Crocker Peter R. E.
Published: March 2009

In this study we explored the experiences of women who were classified as overweight while they participated in a physical activity intervention. In line with interpretative phenomenological analysis, eight women were interviewed prior to and following a 12-week dragon boat physical activity intervention. Data were transcribed verbatim and subjected to individual-level content analysis to explore change that informed group-level idiographic analysis. From the idiographic analysis three distinct profiles were created: (a) women who consistently struggled with negative self-perceptions; (b) women who consistently experienced positive self-perceptions; and (c) women who began with negative self-perceptions and developed more positive self-images. These profiles appeared to be associated with age, since the youngest women placed significant emphasis on the body and physical appearance, whereas the oldest participants reported the most significant shift from importance of body to a greater emphasis on health and well-being. The findings, which are reported in the context of self-determination theory, suggest that women in each of these profiles had unique physical and social self-perceptions and distinct social interactions within the dragon boat intervention.
Reproductive Decisions for Women With HIV: Motherhood's Role in Envisioning a Future
Authors: Barnes Donna B. , Murphy Sheigla
Published: March 2009

Cultural influences might exert more influence on HIV-positive women's reproductive choices than HIV-related conditions. In this article we report on grounded theory research on how women with HIV made reproductive decisions during a time of transition from HIV as potentially fatal to mothers and newborns to its current status as an often controllable chronic illness. Eighty HIV-positive women of childbearing age in three United States cities were interviewed, and the interviews were analyzed using grounded theory techniques. The core concept of the findings was that women's decisions were based on their judgment of the relative weight of positive aspects of motherhood versus the often negative pressures of social and public opinion. These findings have relevance for future research as well as for program development and policy.
Personal Values and Meaning in the Use of Methamphetamine Among HIV-Positive Men Who Have Sex With Men
Authors: Chartier Maggie , Araneta Angela , Duca Lindsey , McGlynn Lawrence M. , Gore-Felton Cheryl , Goldblum Peter , Koopman Cheryl
Published: March 2009

Our aim with this qualitative study was to understand the role of personal values, meaning, and impact of drug use among HIV-positive men who have sex with men (MSM) who struggle with methamphetamine use. Participants were 22 MSM recruited from an ethnically diverse county in the San Francisco Bay area of California. Grounded theory was used to analyze the data collected in individual interviews. Emergent constructs of context, meaning, and perceived impact were identified and are described in a theoretical narrative format. The importance of broadening our understanding of HIV and methamphetamine addiction and their interaction is highlighted. This study contributes to the understanding of the complexity of methamphetamine use within the specific population of MSM living with HIV/ AIDS, and suggests possible directions for addressing important maintaining factors like adaptive use and enhancing factors that could contribute to an individual's ability to make better choices based on meaning and personal values.
Attitudes of Adolescent Spanish Roma Toward Noninjection Drug Use and Risky Sexual Behavior
Authors: Garcia de Cortazar Ainhoa Rodriguez , Cabrera Leon Andres , Hernan Garcia Mariano , Jimenez Nunez Juan Manuel
Published: March 2009

Our objective with this study was to analyze the opinions of a potentially socially marginalized group of Spanish Roma adolescents and young adults about noninjection drug use, HIV infection, and risky sexual behavior. Descriptive qualitative research was conducted through focus groups with Roma participants and semistructured interviews with professionals who work with them in areas such as education and health promotion. Results were triangulated by cross analysis among researchers. Declared drug consumption is lower among females than males. The former claim they do not maintain sporadic sexual relations, and link risky sexual practices to being in love and involved in a stable relationship. Males only use condoms in sporadic sexual relations. They attribute their lack of condom use to lost sensitivity, perceiving sex as something uncontrollable, and not having condoms available when using drugs. Results suggest the need to improve actions aimed at preventing the sexual transmission of HIV among the Roma population.
Level and Intensity of Early Intervention Services for Infants and Toddlers With Disabilities
Authors: Hallam Rena A. , Rous Beth , Grove Jaime , LoBianco Tony
Published: March 2009

Data from a statewide billing and information system for early intervention are used to examine the influence of multiple factors on the level and intensity of services provided in a state early intervention system. Results indicate that child and family factors including entry age, gestational age, Medicaid eligibility, access to third party insurance, and children's developmental skill areas influence the level and the intensity of early intervention services provided. In addition, findings show that county demographic factors also influence service provision, specifically the interaction between rural and poverty status. Implications for social policy are discussed.
The Perception of Elder Sexual Abuse in the Courtroom
Authors: Hodell Emily C. , Golding Jonathan M. , Yozwiak John A. , Bradshaw Gregory S. , Kinstle Terri L. , Marsil Dorothy F.
Published: March 2009

This study explored mock juror perceptions of elder sexual mistreatment (ESM). In Experiment 1, 118 participants read a fictional criminal trial summary of an ESM case in which a 76-year-old woman was allegedly abused by either her son or a neighbor. In Experiment 2 ( n = 360), the ESM occurred in either a nursing home or the elder's home and the alleged perpetrator was either her son or a nursing home worker. Conviction rates were relatively low in both experiments (25% and 33%, respectively). Women were more pro-prosecution than men in case judgments. Overall, the study provides evidence that mock jurors may question the credibility of elders in ESM cases.
Assessing the Impact of Oversight and Procedural Justice on the Attitudes of Individuals Who File Police Complaints
Authors: De Angelis Joseph
Published: March 2009

This article uses the procedural justice perspective and anonymous mailed surveys to examine the effect the implementation of a new citizen oversight agency in one mid-sized Western city had on levels of satisfaction among citizens who filed complaints against police officers. The results indicate that the implementation of the oversight agency improved levels of satisfaction with certain parts of the complaint process, such as the quality of communication and the thoroughness of the process. However, the new citizen agency had no statistically significant direct effect on levels of satisfaction with either the complaint process as a whole or with complaint outcomes.
Mobile-mediated virtual experience in tourism: Concept, typology and applications
Authors: Hyun Martin Yongho , Lee Seoki , Hu Clark
Published: March 2009

The main purpose of this paper is to conceptualize virtual tourism in the mobile context. Through the concept of telepresence, the typology of virtual experience can be explained by two dimensions: vividness and interactivity. The authors first discuss virtual experience in terms of several categories ranging from verbal-based to animated interactive experience. Based on these categories, various mobile applications are then identified to complete the typology. Finally, practical discussions are provided with examples to illustrate various mobile services that facilitate virtual experiences and the application of the mobile-mediated virtual experience to tourism with consideration of the destination marketing organization's innovativeness and consumers' needs for mobile usage.
Development of a Continuous Finishing Chemistry Process for Manufacture of a Phosphorylated Cotton Chronic Wound Dressing
Authors: Edwards J. Vincent , Howley Phyllis , Yachmenev Valeriy , Lambert Allan , Condon Brian
Published: March 2009

A phosphorylated form of cotton gauze for treatment of chronic wounds was designed to improve the wound dressing's capacity to remove harmful proteases from the wound and facilitate healing. Development of the fabric finishing chemistry of the wound dressing with a process suitable for textile mill production required adapting the stationary finishing chemistry of the cotton phosphorylation from a batch-type pad-dry-cure finishing treatment to a continuous pilot scale finishing process. Issues in optimizing the cotton finishing process took into consideration dressing sterilization, the effect of city water versus de-ionized water, retention of the fabric whiteness index and protease sequestration capacity of the dressing, which is the index of the dressing's efficacy. Three types of sterilization approaches were assessed, including gamma ray, ethylene oxide and steam sterilization to determine the effect of sterilization on the phosphorylated cotton dressing and the subsequent efficacy of the sterilized dressing to remove proteases from the wound. Two phosphorylation reagents were compared for their ability to phosphorylate cotton in a urea-based formulation and yield an active, effective dressing, with a high whiteness index. Phosphorylation with a diammonium phosphate (DAP) : urea formulation generally gave a more effective dressing as an active protease sequestrant, and phosphorylation with sodium hexametaphosphate (SMP) : urea gave a higher whiteness index. Finishing formulations combining the two phosphorylating reagents, DAP and SMP: urea, were assessed to improve both whiteness and efficacy. However, sterilization of DAP treated cotton with ethylene oxide eradicated activity through apparent masking of the cellulose phosphate hydroxyls. Side reactions that may occur during ethylene oxide treatment were discussed as the possible origin of the phosphate hydroxyl masking. On the other hand, sterilization with gamma irradiation produced significant yellowing of the dressing. A SMP : urea (16 : 30) formulation was employed in the continuous process finishing treatment, and found to be most optimal for whiteness, efficacy and ease of sterilization, when adapted to industrial scale production of the cotton chronic wound dressing.
Effects of enalapril, candesartan or both on neurohumoral activation and LV volumes and function in patients with heart failure not treated with a beta-blocker
Authors: White Michel , Rouleau Jean-Lucien , Afzal Rizwan , Floras John , Yusuf Salim , McKelvie Robert S.
Published: March 2009

Background: The long-term effects of the angiotensin-receptor blocker candesartan, the angiotensin-converting enzyme inhibitor enalapril or their combination have been incompletely studied in a large cohort of patients with heart failure not treated with beta-blockers. The objective of this study was to investigate the changes in neurohormones and LV volumes and ejection fraction in patients treated with enalapril, candesartan, or enalapril plus candesartan without concomitant beta-blocker therapy.

Methods: Three hundred and ninety-two patients from the RESOLVD pilot study not treated with a beta-blocker at baseline or at any time during the trial were analyzed. Norepinephrine, endothelin-1, big endothelin-1, angiotensin-II, aldosterone, N-terminal proANP, BNP, and radionuclide angiography were measured before and after 43 weeks of treatment with candesartan alone ( n = 162), or enalapril alone ( n = 45), or candesartan plus enalapril ( n = 185). Endpoints were assessed at baseline and after 43 weeks of therapy.

Results: LV end-diastolic and end-systolic volumes increased significantly at 43 weeks in all groups except for patients treated with enalapril plus candesartan. BNP decreased at 43 weeks only in patients receiving dual angiotensin-II suppression (-6.1 ± 37.8 pmol/l). Angiotensin-II levels were significantly increased in patients treated with candesartan (+23.6 ± 47.1 pg/ml; p<0.05).

Conclusion: We conclude that angiotensin-II modulation, with enalapril and candesartan, without concomitant utilization of beta-blocker lead to a decrease in BNP and an attenuation of the increase in LV end-diastolic and end-systolic volumes without a reversal of this process in the long term.
Bayesian clustering and feature selection for cancer tissue samples
Authors: Marttinen Pekka , Myllykangas Samuel , Corander Jukka
Published: March 2009

Background

The versatility of DNA copy number amplifications for profiling and categorization of various tissue samples has been widely acknowledged in the biomedical literature. For instance, this type of measurement techniques provides possibilities for exploring sets of cancerous tissues to identify novel subtypes. The previously utilized statistical approaches to various kinds of analyses include traditional algorithmic techniques for clustering and dimension reduction, such as independent and principal component analyses, hierarchical clustering, as well as model-based clustering using maximum likelihood estimation for latent class models.

Results

While purely algorithmic methods are usually easily applicable, their suboptimal performance and limitations in making formal inference have been thoroughly discussed in the statistical literature. Here we introduce a Bayesian model-based approach to simultaneous identification of underlying tissue groups and the informative amplifications. The model-based approach provides the possibility of using formal inference to determine the number of groups from the data, in contrast to the ad hoc methods often exploited for similar purposes. The model also automatically recognizes the chromosomal areas that are relevant for the clustering.

Conclusion

Validatory analyses of simulated data and a large database of DNA copy number amplifications in human neoplasms are used to illustrate the potential of our approach. Our software implementation BASTA for performing Bayesian statistical tissue profiling is freely available for academic purposes at http://web.abo.fi/fak/mnf/mate/jc/software/basta.html
Fast max-margin clustering for unsupervised word sense disambiguation in biomedical texts
Authors: Duan Weisi , Song Min , Yates Alexander
Published: March 2009

Background

We aim to solve the problem of determining word senses for ambiguous biomedical terms with minimal human effort.

Methods

We build a fully automated system for Word Sense Disambiguation by designing a system that does not require manually-constructed external resources or manually-labeled training examples except for a single ambiguous word. The system uses a novel and efficient graph-based algorithm to cluster words into groups that have the same meaning. Our algorithm follows the principle of finding a maximum margin between clusters, determining a split of the data that maximizes the minimum distance between pairs of data points belonging to two different clusters.

Results

On a test set of 21 ambiguous keywords from PubMed abstracts, our system has an average accuracy of 78%, outperforming a state-of-the-art unsupervised system by 2% and a baseline technique by 23%. On a standard data set from the National Library of Medicine, our system outperforms the baseline by 6% and comes within 5% of the accuracy of a supervised system.

Conclusion

Our system is a novel, state-of-the-art technique for efficiently finding word sense clusters, and does not require training data or human effort for each new word to be disambiguated.
Identification of temporal association rules from time-series microarray data sets
Authors: Nam Hojung , Lee KiYoung , Lee Doheon
Published: March 2009

Background

One of the most challenging problems in mining gene expression data is to identify how the expression of any particular gene affects the expression of other genes. To elucidate the relationships between genes, an association rule mining (ARM) method has been applied to microarray gene expression data. However, a conventional ARM method has a limit on extracting temporal dependencies between gene expressions, though the temporal information is indispensable to discover underlying regulation mechanisms in biological pathways. In this paper, we propose a novel method, referred to as temporal association rule mining (TARM), which can extract temporal dependencies among related genes. A temporal association rule has the form [gene A↑, gene B↓] → (7 min) [gene C↑], which represents that high expression level of gene A and significant repression of gene B followed by significant expression of gene C after 7 minutes. The proposed TARM method is tested with Saccharomyces cerevisiae cell cycle time-series microarray gene expression data set.

Results

In the parameter fitting phase of TARM, the fitted parameter set [threshold = ± 0.8, support ≥ 3 transactions, confidence ≥ 90%] with the best precision score for KEGG cell cycle pathway has been chosen for rule mining phase. With the fitted parameter set, numbers of temporal association rules with five transcriptional time delays (0, 7, 14, 21, 28 minutes) are extracted from gene expression data of 799 genes, which are pre-identified cell cycle relevant genes. From the extracted temporal association rules, associated genes, which play same role of biological processes within short transcriptional time delay and some temporal dependencies between genes with specific biological processes are identified.

Conclusion

In this work, we proposed TARM, which is an applied form of conventional ARM. TARM showed higher precision score than Dynamic Bayesian network and Bayesian network. Advantages of TARM are that it tells us the size of transcriptional time delay between associated genes, activation and inhibition relationship between genes, and sets of co-regulators.
Two-dimensional gel proteome reference map of human small intestine
Authors: Simula Maria Paola , Cannizzaro Renato , Marin Maria Dolores , Pavan Alessandro , Toffoli Giuseppe , Canzonieri Vincenzo , De Re Valli
Published: March 2009

Background

The small intestine is an important human organ that plays a central role in many physiological functions including digestion, absorption, secretion and defense. Duodenal pathologies include, for instance, the ulcer associated to Helicobacter Pylori infection, adenoma and, in genetically predisposed individuals, celiac disease. Alterations in the bowel reduce its capability to absorb nutrients, minerals and fat-soluble vitamins. Anemia and osteopenia or osteoporosis may develop as a consequence of vitamins malabsorption. Adenoma is a benign tumor that has the potential to become cancerous. Adult celiac disease patients present an overall risk of cancer that is almost twice than that found in the general population. These disease processes are not completely known.

To date, a two dimensional (2D) reference map of proteins expressed in human duodenal tissue is not yet available: the aim of our study was to characterize the 2D protein map, and to identify proteins of duodenal mucosa of adult individuals without duodenal illness, to create a protein database. This approach, may be useful for comparing similar protein samples in different laboratories and for the molecular characterization of intestinal pathologies without recurring to the use of surgical material.

Results

The enrolled population comprised five selected samples (3 males and 2 females, aged 19 to 42), taken from 20 adult subjects, on their first visit at the gastroenterology unit for a suspected celiac disease, who did not turn to be affected by any duodenal pathology after gastrointestinal and histological evaluations. Proteins extracted from the five duodenal mucosal specimens were singly separated by 2D gel electrophoresis. After image analysis of each 2D gel, 179 protein spots, representing 145 unique proteins, from 218 spots tested, were successfully identified by MALDI-TOF ms analysis. Normalized volumes, for each protein, have been reported for every gel. Proteins have been grouped according to their biological/metabolic functions.

Conclusion

This study represents to date the first detailed and reproducible 2D protein map of human duodenum. Spots identifications, reported in a database, will be helpful to identify the variability in protein expression levels, in isoforms expression, or in post-translational modifications associated to pathology or to a therapy.
Dietary supplementation of mannan-oligosaccharide enhances neonatal immune responses in chickens during natural exposure to Eimeria spp
Authors: Gómez-Verduzco Gabriela , Cortes-Cuevas Arturo , López-Coello Carlos , Ávila-González Ernesto , Nava Gerardo M
Published: March 2009

Background

Control and eradication of intestinal infections caused by protozoa are important biomedical challenges worldwide. Prophylactic control of coccidiosis has been achieved with the use of anticoccidial drugs; however, the increase in anticoccidial resistance has raised concerns about the need for new alternatives for the control of coccidial infections. In fact, new strategies are needed to induce potent protective immune responses in neonatal individuals.

Methods

The effects of a dietary supplementation of mannan-oligosaccharide (yeast cell wall; YCW) on the local, humoral and cell-mediated immune responses, and intestinal replication of coccidia were evaluated in a neonatal animal model during natural exposure to Eimeria spp. A total of 840 one-day-old chicks were distributed among four dietary regimens: A) Control diet (no YCW) plus anticoccidial vaccine); B) Control diet plus coccidiostat; C) YCW diet plus anticoccidial vaccination; and D) YCW diet plus coccidiostat. Weight gain, feed consumption and immunological parameters were examined within the first seven weeks of life.

Results

Dietary supplementation of 0.05% of YCW increased local mucosal IgA secretions, humoral and cell-mediated immune responses, and reduced parasite excretion in feces.

Conclusion

Dietary supplementation of yeast cell wall in neonatal animals can enhance the immune response against coccidial infections. The present study reveals the potential of YCW as adjuvant for modulating mucosal immune responses.
C. elegans mig-6encodes papilin isoforms that affect distinct aspects of DTC migration, and interacts genetically withmig-17andcollagen IV
Authors: Kawano Takehiro , Zheng Hong , Merz David C. , Kohara Yuji , Tamai Katsuyuki K. , Nishiwaki Kiyoji , Culotti Joseph G.
Published: March 2009

The gonad arms of C. elegans hermaphrodites acquire invariant shapes by guided migrations of distal tip cells (DTCs), which occur in three phases that differ in the direction and basement membrane substrata used for movement. We found that mig-6 encodes long (MIG-6L) and short(MIG-6S) isoforms of the extracellular matrix protein papilin, each required for distinct aspects of DTC migration. Both MIG-6 isoforms have a predicted N-terminal papilin cassette, lagrin repeats and C-terminal Kunitz-type serine proteinase inhibitory domains. We show that mutations affecting MIG-6L specifically and cell-autonomously decrease the rate of post-embryonic DTC migration, mimicking a post-embryonic collagen IV deficit. We also show that MIG-6S has two separable functions - one in embryogenesis and one in the second phase of DTC migration. Genetic data suggest that MIG-6S functions in the same pathway as the MIG-17/ADAMTS metalloproteinase for guiding phase 2 DTC migrations, and MIG-17 is abnormally localized in mig-6class-s mutants. Genetic data also suggest that MIG-6S and non-fibrillar network collagen IV play antagonistic roles to ensure normal phase 2 DTC guidance.
Elastic fracture mechanics analysis of thick-walled curved tubing with a semi-elliptical surface crack by the boundary element method
Authors: Plante K I , Tan C-L
Published: March 2009

In this paper, the boundary element method is used to obtain the mode I stress intensity factors (SIFs) for a semi-elliptical crack in thick-walled curved tubing or elbow under internal pressure. A relatively wide range of geometric parameters for the tubing – the bend radius ratio, the cross-sectional radius ratio, and the angular extent of the circular bend – is considered. For each case of the curved tube geometry, a crack of semi-minor to semi-major axis ratio of 0.8, with depth varying from 20 per cent to 80 per cent of the wall thickness at the intrados is analysed. The computed values of the normalized SIFs are shown to be higher than those corresponding to a straight cylinder for the same relative crack depth and cross-sectional radius ratio. They are also found not to vary significantly along much of the crack periphery in the cases considered, increasing rapidly only as the free surface is approached. Furthermore, for a given relative crack size and location, they increase with decreasing bend radius ratio and decreasing cross-sectional radius ratio, but are, however, less sensitive to the angular extent of the elbow.
Experimental analysis of the contact pressure distribution in an off-road tyre
Authors: Cirello A , Marannano G , Virzì Mariotti G
Published: March 2009

This paper presents the results of an extended method of measurement on a tyre for an off-road vehicle 175/82 R16, inserting Prescale paper at the contact with the ground. The experimental analysis of the pressures is carried out, in a cross-sectional direction, in five zones corresponding to the middle of the single dowels that constitute the tread. The results are analysed by means of suitable software so as to refer easily to the value of the pressure. The obtained results are critically analysed and the results are compared with those obtained by the formulae of Rowland and MacLaurin, and by the nominal pressure at the ground, concluding that the expression of MMP for vehicles on wheels is simply to consider a pointer of the performances, in comparison with other vehicles or wheels, rather than a real prediction of the pressure on the ground. Furthermore, a good agreement is found between the tyre deflection calculated and measured experimentally.
Modelling of micro-electrodischarge machining during machining of titanium alloy Ti—6Al—4V using response surface methodology and artificial neural network algorithm
Authors: Pradhan B B , Bhattacharyya B
Published: March 2009

Micro-electrodischarge machining (EDM) can produce microhole and other complex three-dimensional features on a wide range of conductive engineering materials such as titanium super alloy, inconel, etc. The micromachining of titanium super alloy (Ti—6Al—4V) is in very high demand because of its various applications in aerospace, automotive, biomedical, and electronics industries, owing to its good strength-to-weight ratio and excellent corrosion-resistant properties. The present research study deals with the response surface methodology (RSM) and artificial neural network (ANN) with back-propagation-algorithm-based mathematical modelling. Furthermore, optimization of the machining characteristics of micro-EDM during the microhole machining operation on Ti—6Al—4V has been carried out. The matrix experiments have been designed based on rotatable central composite design. Peak-current (Ip), pulse-on time (Ton), and dielectric flushing pressure have been considered as process parameters during the microhole machining operation and these parameters were utilized for developing the ANN predicting model. The performance measures for optimization were material removal rate (MRR), tool wear rate (TWR), and overcut (OC). The ANN model was developed using a back-propagation neural network algorithm, which was trained with response values obtained from the experimental results. The Levenberg—Marquardt training algorithm has been used for a multilayer feed-forward network. The developed model was validated using data obtained by conducting a set of test experiments. The optimal combination of process parametric settings obtained are pulse-on-time of 14.2093 μs, peak current of 0.8363 A, and flushing pressure of 0.10 kg/cm2 for achieving the desired MRR, TWR, and OC. The output of RSM optimal data was validated through experimentation and the ANN predicted model. A close agreement was observed among the actual experimental, RSM, and ANN predictive results.
Effect of roller nose radius and release angle on the forming quality of a hot-spinning process using a non-linear finite element shell analysis
Authors: Lexian H , Dariani B M
Published: March 2009

This research presents a non-linear dynamic finite element (FE) analysis of a tube-spinning process based on the Belytschko—Lin—Tsay shell element with an explicit time integration scheme. A brief description of the FE formulation of a first-order shear deformation shell element as well as plane stress elastoplastic analysis, internal forces calculation, nodal mass calculation, and prediction of stable time step are presented. An explicit FE code is designed and its implementation algorithm is described in detail. The optimum geometry of a roller is attained using the FE simulations of a hot-spinning process with various roller geometries. The dome-forming process of a seamless pressure vessel using modified roller geometry is performed to confirm the successful process predicted by FE simulation. The vessel is cut longitudinally and its profile is measured. A comparison between longitudinal cross-section profiles calculated by the FE analysis and that obtained from the experiment shows a good agreement.
Comparison of material transfer in electrical discharge machining of AISI H13 die steel
Authors: Kumar S , Singh R , Singh T P , Sethi B L
Published: March 2009

The electrical discharge machining (EDM) process is extensively used in the tool and die making industry for accurate machining of internal profiles in hardened materials. Although it is essentially a material removal process, efforts have been made in the recent past to use it as surface treatment method. This article investigates and compares the effect of material transfer from electrode bodies (copper, copper—chromium, and copper—tungsten) and tungsten powder suspended in the dielectric medium during die-sinking EDM of AISI H13 die steel. Results show a 76 per cent increase in micro-hardness by machining with a copper—tungsten electrode and a 111 per cent increase by machining with tungsten powder mixed in the dielectric. The copper—chromium electrode gives the best surface roughness (Ra) value of 2.67 μ m. Scanning electron microscopy and X-ray diffraction analysis of the machined surfaces show alloying of parent material with tungsten and tungsten carbide. Chemical composition of the machined surfaces was further checked on an optical emission spectrometer to verify the results. Besides a significant presence of tungsten, an increase in the percentage of carbon is also observed.