bluuebunny/crossref_metadata_2025 huggingface dataset:
Organizational and Market Influences on Physician Performance on Patient Experience Measures
Authors: Rodriguez Hector P. , Von Glahn Ted , Rogers William H. , Safran Dana Gelb
Published: March 2009

Objective. To examine the extent to which medical group and market factors are related to individual primary care physician (PCP) performance on patient experience measures.

Data Sources. This study employs Clinician and Group CAHPS survey data (n=105,663) from 2,099 adult PCPs belonging to 34 diverse medical groups across California. Medical group directors were interviewed to assess the magnitude and nature of financial incentives directed at individual physicians and the adoption of patient experience improvement strategies. Primary care services area (PCSA) data were used to characterize the market environment of physician practices.

Study Design. We used multilevel models to estimate the relationship between medical group and market factors and physician performance on each Clinician and Group CAHPS measure. Models statistically controlled for respondent characteristics and accounted for the clustering of respondents within physicians, physicians within medical groups, and medical groups within PCSAs using random effects.

Principal Findings. Compared with physicians belonging to independent practice associations, physicians belonging to integrated medical groups had better performance on the communication ( p=.007) and care coordination ( p=.03) measures. Physicians belonging to medical groups with greater numbers of PCPs had better performance on all measures. The use of patient experience improvement strategies was not associated with performance. Greater emphasis on productivity and efficiency criteria in individual physician financial incentive formulae was associated with worse access to care ( p=.04). Physicians located in PCSAs with higher area‐level deprivation had worse performance on the access to care ( p=.04) and care coordination ( p<.001) measures.

Conclusions. Physicians from integrated medical groups and groups with greater numbers of PCPs performed better on several patient experience measures, suggesting that organized care processes adopted by these groups may enhance patients' experiences. Physicians practicing in markets with high concentrations of vulnerable populations may be disadvantaged by constraints that affect performance. Future studies should clarify the extent to which performance deficits associated with area‐level deprivation are modifiable.
Imbricate thrust stack model for the formation of glaciotectonic rafts: an example from the Middle Pleistocene of north Norfolk, UK
Authors: BURKE HELEN , PHILLIPS EMRYS , LEE JONATHAN R. , WILKINSON IAN P.
Published: March 2009

In this article, we present a glaciotectonic model for raft emplacement based on a study of large‐scale and small‐scale deformation structures associated with the accretion of chalk rafts at three Middle Pleistocene sites on the north Norfolk coast, eastern England. Detailed structural measurements taken from the three localities indicate an overall sense of ice movement and raft emplacement towards the south/southeast, suggesting a source area for the rafts located to the north of the present Norfolk coast in the offshore area of the North Sea. Provenancing of the chalk rafts, based on analysis of the foraminifera, also indicates a northern nearshore provenance for the chalk. Mechanisms for the detachment, transport and accretion of the rafts are explored, and it is concluded that pressurized pore water played an important role in all three phases. An imbricate thrust stack model of glaciotectonic raft generation is presented, with the structural history of raft emplacement explained by the geometric relationships between the large‐scale basal shear planes and associated deformation structures within adjacent preglacial and glacial sediments.
Functional Limitations, Socioeconomic Status, and All‐Cause Mortality in Moderate Alcohol Drinkers
Authors: Lee Sei J. , Sudore Rebecca L. , Williams Brie A. , Lindquist Karla , Chen Helen L. , Covinsky Kenneth E.
Published: March 2009

OBJECTIVES: To determine whether the survival benefit associated with moderate alcohol use remains after accounting for nontraditional risk factors such as socioeconomic status (SES) and functional limitations.

DESIGN: Prospective cohort.

SETTING: The Health and Retirement Study (HRS), a nationally representative study of U.S. adults aged 55 and older.

PARTICIPANTS: Twelve thousand five hundred nineteen participants were enrolled in the 2002 wave of the HRS.

MEASUREMENTS: Participants were asked about their alcohol use, functional limitations (activities of daily living, instrumental activities of daily living, and mobility), SES (education, income, and wealth), psychosocial factors (depressive symptoms, social support, and the importance of religion), age, sex, race and ethnicity, smoking, obesity, and comorbidities. Death by December 31, 2006, was the outcome measure.

RESULTS: Moderate drinkers (1 drink/d) had a markedly more‐favorable risk factor profile, with higher SES and fewer functional limitations. After adjusting for demographic factors, moderate drinking (vs no drinking) was strongly associated with less mortality (odds ratio (OR)=0.50, 95% confidence interval (CI)=0.40–0.62). When traditional risk factors (smoking, obesity, and comorbidities) were also adjusted for, the protective effect was slightly attenuated (OR=0.57, 95% CI=0.46–0.72). When all risk factors including functional status and SES were adjusted for, the protective effect was markedly attenuated but still statistically significant (OR=0.72, 95% CI=0.57–0.91).

CONCLUSION: Moderate drinkers have better risk factor profiles than nondrinkers, including higher SES and fewer functional limitations. Although these factors explain much of the survival advantage associated with moderate alcohol use, moderate drinkers maintain their survival advantage even after adjustment for these factors.
Visibility of Latin American Nursing Research (1959–2005)
Authors: Mendoza‐Parra Sarah , Paravic‐Klijn Tatiana , Muñoz‐Muñoz Ana María , Barriga Omar A. , Jiménez‐Contreras Evaristo
Published: March 2009

Objectives:To analyze scientific activity in Latin American nursing using bibliometric indicators.

Materials and Methods:This is a quantitative, descriptive study of the universe of Latin American nursing journals (119) and scientific documents (13,208) published according to current library databases including: the Web of Science (WOS), Medline, LILACS, Periodica, Cuiden, and SciELO. A database was prepared using ProCite®.

Results:The PAHO (Pan American Health Organization) Open‐access Directory of Latin American Nursing Journals includes the greatest number of the 119 journal titles (60%). The average journal longevity is 11.3 years and Brazil produces the greatest percentage (31.9%) of journals. Of the current journals, 55% do not have international readership. The non‐Latin American countries that contribute most to document diffusion are Spain, the United States, and England. The doubling time of scientific production of documents is 7.3 years and the annual growth rate is 10%; 2% of researchers form the most productive group of authors. Only in recent years has the number of contributions to the ISI nursing category begun to stabilize.

Conclusions:Latin American scientific nursing production is still growing exponentially and Latin American nursing contributions to knowledge being disseminated through databases of recognized scientific quality seem to be increasing. The current scientific task is to organize and improve the publication processes.

Clinical Relevance:We describe the conditions in which Latin American nursing research has become institutionalized, the challenges that it has faced, and the gradual incorporation of such research into international science.
A 2‐Decade Appraisal of African Nursing Scholarship: 1986–2006
Authors: Adejumo Oluyinka , Lekalakala‐Mokgele Eucebious
Published: March 2009

Purpose: This paper is a description of a study about articles published about nursing in Africa from 1986 to 2006.

Methods: An exhaustive database search of articles written by nurses or articles related to nursing in Africa was done. Access to the database was mainly via EBSCO (http://www.ebsco.com), which allowed searching seven electronic databases. These are major databases useful for finding and accessing articles in academic journals, repositories, and archives. Data were recorded on computer spreadsheets and analyzed using frequencies and percentages.

Findings: A total of 1,860 indexed research studies were categorized and analysed for themes, content, source of publication, location, subject, scientific or nonscientific methods, nursing or non‐nursing research, clinical or nonclinical nursing. A progressive increase of publications was noted. Regional variations were observed in the number of publications over the years with most from Southern Africa (67.3%) compared to West Africa (5.2%) and East Africa (3.3%). Common themes were nursing education (11.9%) HIV/AIDS (11.9%), community health care (16.1%), and professional nursing issues (10.3%). Single authorship (90.7%) outnumbered multiple authorship (9.3%), though research‐based (50.5%) and nonresearch‐based articles (49.5%) were almost evenly distributed.

Conclusions and Recommendations: More emphasis will be required for research concerning clinical studies; and collaborations—particularly multinational and across regions of Africa—should be developed. Efforts should be intensified to continue to build research capacity among nurses.

Clinical Relevance: Emphasis on African‐based clinical studies which directly relate to patient care and culture can advance evidence‐based practice in nursing with particular reference to African settings.
Make books, not war: workshops at a summer camp in Bosnia
Authors: Darvin Jacqueline
Published: March 2009

This article focuses on a bookmaking project that was conducted with pre‐adolescent Serbian and Bosnian girls at a summer camp outside Sarajevo, Bosnia in 2005. During this camp, children from Bosnia, Serbia and Croatia were brought together by the Global Children's Organisation to engage in a variety of activities, including conflict resolution, art, athletics and academics. The literacy workshops that were offered gave the children the opportunity to write, illustrate and construct their own books about topics such as peace, friendship and the preservation of nature in Bosnia. The workshops were conducted in English and Serbo‐Croatian, using a variety of pedagogical strategies. Upon completion of their books, the girls hosted a ‘story hour’ for the younger children at the camp and their stories were read aloud and discussed. This article explores the story telling of children in post‐war Bosnia (through writing samples) and discusses the powerful social component of literacy events and their ability to unite and heal disparate groups. Additionally, this article explores writing as a means of imagining a more hopeful future and how as writers, children are shapers of their own cultures and of their individual and collaborative identities within those cultures.
TDP‐43 Redistribution is an Early Event in Sporadic Amyotrophic Lateral Sclerosis
Authors: Giordana Maria Teresa , Piccinini Marco , Grifoni Silvia , De Marco Giovanni , Vercellino Marco , Magistrello Michela , Pellerino Alessia , Buccinnà Barbara , Lupino Elisa , Rinaudo Maria Teresa
Published: March 2009

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder consisting of progressive loss of motor neurons. TDP‐43 has been identified as a component of ubiquitin‐immunoreactive inclusions of motor neurons in ALS. We focused on the diffuse cytoplasmic TDP‐43 immunoreactivity in ALS neurons, and quantitatively assessed it in comparison with skein/round TDP‐43 and ubiquitin immunostaining in motor neurons of 30 sporadic ALS cases. The percentage of spinal motor neurons with cytoplasmic TDP‐43 immunoreactivity was higher than that of ubiquitin‐immunoreactive ones. The percentage of TDP‐43‐positive motor neurons was independent of neuron counts in anterior horns, while the percentage of ubiquitinated neurons was inversely correlated. Aiming to define the cytosolic localization of TDP‐43, the immunoblot analysis of spinal cord and frontal cortex showed that full‐length TDP‐43, the 45 kDa form and ubiquitinated TDP‐43 are found in the soluble inclusion‐free fraction. The present data suggest that delocalization, accumulation and ubiquitination of TDP‐43 in the cytoplasm of motor neurons are early dysfunctions in the cascade of the events leading to motor neuron degeneration in ALS, preceding the formation of insoluble inclusion bodies. Being cytoplasmic accumulation an ongoing event during the course of the illness, a therapeutic approach to this incurable disease can be envisaged.
Narrative and Collaborative Practices in Work With Families that are Homeless
Authors: Fraenkel Peter , Hameline Thomas , Shannon Michele
Published: March 2009

This article reports on the use of narrative therapy ideas and practices in working with families that are homeless in a shelter‐based, multiple‐family discussion group program called Fresh Start for Families. It begins with a review of the challenges facing homeless families. It then briefly describes the collaborative methods used to develop the program. It then describes a range of practices and activities that provide opportunities for families to be witnessed in telling their stories of challenge and coping, to help and be helped by other families experiencing similar challenges, to reconnect and strengthen a positive sense of family identity while externalizing the constraining, stigmatizing descriptions associated with homelessness, and to envision and take steps towards their preferred futures.
Comparison of Family Therapy Outcome With Alcohol‐Abusing, Runaway Adolescents
Authors: Slesnick Natasha , Prestopnik Jillian L
Published: March 2009

Treatment evaluation for alcohol problem, runaway adolescents and their families is rare. This study recruited primary alcohol problem adolescents (N = 119) and their primary caretakers from two runaway shelters and assigned them to (a) home‐based ecologically based family therapy (EBFT), (b) office‐based functional family therapy (FFT), or (c) service as usual (SAU) through the shelter. Findings showed that both home‐based EBFT and office‐based FFT significantly reduced alcohol and drug use compared with SAU at 15‐month postbaseline. Measures of family and adolescent functioning improved over time in all groups. However, significant differences among the home‐ and office‐based interventions were found for treatment engagement and moderators of outcome.
COI barcodes for identification ofMerodonhoverflies (Diptera, Syrphidae) of Lesvos Island, Greece
Authors: STÅHLS G. , VUJIC A. , PÉREZ‐BAÑON C. , RADENKOVIC S. , ROJO S. , PETANIDOU T.
Published: March 2009

DNA barcoding has become a useful system for linking different biological life stages, and for identification of species within a known taxonomic framework. In this study, we generated mitochondrial DNA COI barcodes using adult specimens of all 22 species of the hoverfly genusMerodon(Diptera, Syrphidae) occurring on Lesvos island (Greece). The generated COI barcodes could well discriminate between allMerodontaxa of Lesvos, except forM. loewiandM. papillusthat shared the same haplotype, despite their clear morphological differences. In addition, the barcodes revealed two cases of hitherto unknown morphologically cryptic species close toM. avidusandM. nigritarsis, respectively. Because only few successful rearings of immature stages ofMerodonhoverflies are available, the larval host plant remains unknown for these phytophagous taxa. The obtained COI barcode library for theMerodonspp. of Lesvos will constitute a tool to link any unknown immature stages with already known species, and thus provide important life‐history information and promise for ecological studies.
Overexpression of Twist in colorectal adenocarcinoma
Authors: Hong Ran , Lim Sung‐Chul
Published: March 2009

Background and aim: Twist, a basic helix‐loop‐helix (bHLH) transcription factor, is a master regulator of gastrulation and mesoderm specification. Twist has now been characterized as a newly found epithelial‐mesenchymal transition (EMT)‐inducer and has been shown to be involved in tumor invasiveness and metastasis. The aim of the present study was to examine the pattern of Twist expression in colorectal adenocarcinoma (CRA) and to compare the expression of Twist and E‐cadherin as determined by immunohistochemical analysis. Methods: A semiquantitative scoring system was applied based on the intensity and the extent of positive expression in cancer cells. Results: Twist was not detected in non‐neoplastic mucosa, but immunoreactivity was evident in 86.2% of CRA. Expression of Twist was significantly associated with tumor invasion (P= 0.001) and differentiation (P= 0.003), and showed inverse correlation with E‐caherin expression (P= 0.045). Twist expression did not influence overall survival. Conclusions: We demonstrated, for the first time, that Twist is up‐regulated in CRA. These results demonstrated that a positive role of Twist in tumor invasion in CRA, and inverse correlation of Twist and E‐cadherin expression suggest that Twist may play some role in the EMT by inhibition of E‐cadherin activity.
Potency and Bactericidal Activity of Iclaprim against Recent Clinical Gram-Positive Isolates
Authors: Sader Helio S. , Fritsche Thomas R. , Jones Ronald N.
Published: March 2009

The in vitro activity of iclaprim, a novel diaminopyrimidine derivative, was evaluated against 5,937 recent gram-positive clinical isolates collected in the United States and Europe. Iclaprim demonstrated potent activity against
Staphylococcus aureus
(including methicillin-resistant
S. aureus
[MRSA]), beta-hemolytic
Streptococcus
spp., and
Enterococcus faecalis
strains tested. In addition, iclaprim exhibited bactericidal activity against all
S. aureus
strains tested, including MRSA.
Differing Effects of Combination Chemotherapy with Meropenem and Tobramycin on Cell Kill and Suppression of Resistance of Wild-TypePseudomonas aeruginosaPAO1 and Its Isogenic MexAB Efflux Pump-Overexpressed Mutant
Authors: Drusano G. L. , Liu Weiguo , Fregeau Christine , Kulawy Robert , Louie Arnold
Published: March 2009

The drug interaction terminology (synergy, additivity, antagonism) relates to bacterial kill. The suppression of resistance requires greater drug exposure. We examined the combination of meropenem and tobramycin for kill and resistance suppression (wild-typePseudomonas aeruginosaPAO1 and its isogenic MexAB-overexpressed mutant). The drug interaction was additive. The introduction of MexAB overexpression significantly altered the 50% inhibitory concentration of meropenem but not that of tobramycin, resulting in the recovery of a marked increase in colony numbers from drug-containing plates. For the wild type, more tobramycin-resistant isolates than meropenem-resistant isolates were present, and the tobramycin-resistant isolates were harder to suppress. MexAB overexpression unexpectedly caused a significant increase in the number of tobramycin-resistant mutants, as indexed to the area under the curve of slices through the inverted U resistance mountain. The differences were significant, except in the absence of meropenem. We hypothesize that the pump resulted in the presence of less meropenem for organism inhibition, allowing more rounds of replication and also affecting the numbers of tobramycin-resistant mutants. When resistance suppression is explored by combination chemotherapy, it is important to examine the impacts of differing resistance mechanisms for both agents.
Synthesis of novel racemic carbocyclic nucleoside analogues derived from 4,8-dioxatricyclo[4.2.1.03,7]nonane-9-methanol and 4-oxatricyclo[4.3.1.03,7]decane-10-methanol, compounds with activity against Coxsackie viruses
Authors: Hřebabecký Hubert , Dračínský Martin , De Palma Armando M. , Neyts Johan , Holý Antonín
Published: March 2009

(1R*,2R*,3R*,4S*)-7-Oxabicyclo[2.2.1]hept-5-ene-2,3-dimethanol (10) and (1R*,2R*,3R*,4S*)-bicyclo[2.2.2]oct-5-ene-2,3-dimethanol (14), which were prepared by the Diels–Alder reaction and subsequent reduction with lithium aluminium hydride, were treated with benzyl azidoformate to give benzylN-[(1R*,2R*,3S*,6S*,7S*,9S*)-9-(hydroxymethyl)-4,8-dioxatricyclo[4.2.1.03,7]nonan-2-yl]carbamate (11) and benzylN-[(1R*,2R*,3R*,6R*,7S*,10S*)-10-(hydroxymethyl)-4-oxatricyclo[4.3.1.03,7]decan-2-yl]carbamate (15). Hydrogenolysis of carbamates11or15afforded (1R*,2R*,3S*,6S*,7S*,9S*)-2-amino-4,8-dioxatricyclo[4.2.1.03,7]nonane-9-methanol (12) or (1R*,2R*,3R*,6R*,7S*,10S*)-2-amino-4-oxatricyclo[4.3.1.03,7]decane-10-methanol (16). The amines12and16were transformed to thymine and purine nucleoside analogues. The target compounds were tested for the activity againstCoxsackievirus.
Functional analysis of three AHL autoinducer synthase genes in Mesorhizobium loti reveals the important role of quorum sensing in symbiotic nodulation
Authors: Yang Menghua , Sun Kejing , Zhou Lei , Yang Ruifu , Zhong Zengtao , Zhu Jun
Published: March 2009

One of the most important signal transduction pathways in bacteria, quorum sensing, is involved in many regulatory circuits in rhizobia, especially in the control of communication between rhizobia and their plant hosts. In this study, we identified 3 autoinducer synthase genes — mrlI1, mrlI2, and mrlI3 — in Mesorhizobium loti NZP 2213. We found that MrlI1 and MrlI2 could synthesize distinct N-acyl homoserine lactone (AHL) autoinducers in rich medium cultures, and the expression of mrlI1 was shown to be growth-phase-dependent. MrlI3 did not produce any detectable AHL molecules under the culture conditions tested. To investigate whether these AHL synthases affect nodulation, we examined the nodulation of AHL-deficient mutants on their native plant host Lotus corniculatus and found that the efficiency of nodulation of bacteria with mutations of any of these 3 synthase genes was reduced, suggesting that quorum sensing systems in M. loti may play an important role in successful establishment of rhizobium–legume symbiosis.
Natal dispersal and social organization of the swamp antechinus (Antechinus minimus) in a high-density island population
Authors: Sale M. G. , Kraaijeveld-Smit F.J.L. , Arnould J.P.Y.
Published: March 2009

Radiotelemetry, mark–recapture trapping, and microsatellite analysis of genetic variation among three subpopulations were used to investigate the natal dispersal patterns, genetic structure, and social organization within a high-density island population of an insectivorous marsupial, the swamp antechinus ( Antechinus minimus (É. Geoffroy Saint-Hilaire, 1803)). Both demographic and genetic data indicated a high degree of philopatry for both sexes. Associated with high philopatry is low gene flow, often leading to high population genetic structuring. However, there was only weak evidence to support this; allele frequencies and genotype composition of one population tended to be different from the other two. Interestingly, timing of breeding of this subpopulation was delayed compared with the other two subpopulations. The philopatry of both sexes and the apparent lack of kin avoidance behaviour could lead to inbreeding. However, no apparent inbreeding effects were observed and offspring survival was high compared with mainland populations. The fact that male home-range size increased during the breeding season, overlapping with several females, and single females were found nesting with different males at the time of mating (and vice versa) indicates a promiscuous mating system. Potentially, this may reduce inbreeding to some extent. Alternatively, inbreeding may not be purposefully avoided, potentially leading to purging of detrimental alleles, thereby reducing their damaging effects on inbreeding.
SOLVABLE MODEL KINETIC EQUATIONS WITH NON-BOLTZMANN PROPERTIES
Authors: MCKELLAR BRUCE H. J. , OKUNIEWICZ IVONA , QUACH JAMES
Published: March 2009

We reconsider the question of the relative importance of single particle effects and correlations in the solvable interacting neutrino models introduced by Friedland and Lunardini and by Bell, Rawlinson and Sawyer. We show, by an exact calculation, that the two particle correlations are not "small," and that they dominate the time evolution in these models, in spite of indications to the contrary from the rate of equilibration. The failure of the Boltzmann single particle approximation in this model is tentatively attributed to the simplicity of the model, in particular the restriction to two-flavor mixing, and the neglect of the position dependence of the interaction.
EXISTENCE AND UNIQUENESS OF STRONG SOLUTIONS FOR A COMPRESSIBLE MULTIPHASE NAVIER–STOKES MISCIBLE FLUID-FLOW PROBLEM IN DIMENSION n = 1
Authors: MICHOSKI C. , VASSEUR A.
Published: March 2009

We prove the global existence and uniqueness of strong solutions for a compressible multifluid described by the barotropic Navier–Stokes equations in dim = 1. The result holds when the diffusion coefficient depends on the pressure. It relies on a global control in time of the L2 norm of the space derivative of the density, via a new kind of entropy.
QUANTIFYING SOCIAL AND OPPORTUNISTIC BEHAVIOR IN EMAIL NETWORKS
Authors: GOMES LUIZ H. , ALMEIDA VIRGILIO A. F. , ALMEIDA JUSSARA M. , CASTRO FERNANDO D. O. , BETTENCOURT LUÍS M. A.
Published: March 2009

Email graphs have been used to illustrate the general properties of social networks of communication and collaboration. However, increasingly, the majority of Internet traffic reflects opportunistic rather than symbiotic social relations. Here we use email data drawn from a large university to construct directed graphs of email exchange that quantify the differences between social and opportunistic behavior, represented by legitimate messages and spam, respectively. We show that while structural characteristics typical of other social networks are shared to a large extent by the legitimate component, they are not characteristic of opportunistic traffic. To complement the graph analysis, which suffers from incomplete knowledge of users external to the domain, we study temporal patterns of communication to show dynamical properties of email traffic. The results indicate that social email traffic has lower entropy (higher structural information) than opportunistic traffic for periods covering both working and non-working hours. We see in general that both social and opportunistic traffics are not random, and that social email shows stronger temporal structure with a high probability for long silences and bursts of a few messages. These findings offer insights into the fundamental differences between social and opportunistic behavior in email networks, and may generalize to the structure of opportunistic social relations in other environments.
INNOVATION IN HIGH-TECHNOLOGY SMES: INSIGHTS FROM SINGAPORE
Authors: DAS SHOBHA S. , ZHENG HAOYING
Published: March 2009

Researchers have examined innovation by small and medium enterprises (SMEs), identified factors that contribute to innovation, and concluded that SMEs tend to be innovative and innovation improves performance. Do these findings hold for high-technology SMEs that are located in a newly industrialized economy? Drawing on the resource-based view of the firm, and literature from entrepreneurship and innovation studies, we develop and test hypotheses using quantitative data collected from a survey. While the results of the study generally support prior research conclusions, there is a surprising finding: top management experience negatively moderates the effect of innovation on performance. Qualitative data from follow-up interviews with CEOs of SMEs helped us understand this finding.
NEW EXAMPLES OF FINITELY PRESENTED GROUPS WITH STRONG FIXED POINT PROPERTIES
Authors: CHATTERJI INDIRA , KASSABOV MARTIN
Published: March 2009

We give an explicit finite presentation of a group normally generated by SL∞(ℤ). As a consequence, such a group cannot act on e.g. a finite dimensional contractible manifold or on a compact manifold.
SBA
Authors: Lourakis Manolis I. A. , Argyros Antonis A.
Published: March 2009

Bundle adjustment constitutes a large, nonlinear least-squares problem that is often solved as the last step of feature-based structure and motion estimation computer vision algorithms to obtain optimal estimates. Due to the very large number of parameters involved, a general purpose least-squares algorithm incurs high computational and memory storage costs when applied to bundle adjustment. Fortunately, the lack of interaction among certain subgroups of parameters results in the corresponding Jacobian being sparse, a fact that can be exploited to achieve considerable computational savings. This article presents sba, a publicly available C/C++ software package for realizing generic bundle adjustment with high efficiency and flexibility regarding parameterization.
Adaptive Winograd's matrix multiplications
Authors: D'Alberto Paolo , Nicolau Alexandru
Published: March 2009

Modern architectures have complex memory hierarchies and increasing parallelism (e.g., multicores). These features make achieving and maintaining good performance across rapidly changing architectures increasingly difficult. Performance has become a complex tradeoff, not just a simple matter of counting cost of simple CPU operations.

We present a novel, hybrid, and adaptive recursive Strassen-Winograd's matrix multiplication (MM) that uses automatically tuned linear algebra software (ATLAS) or GotoBLAS. Our algorithm applies to any size and shape matrices stored in either row or column major layout (in double precision in this work) and thus is efficiently applicable to both C and FORTRAN implementations. In addition, our algorithm divides the computation into equivalent in-complexity sub-MMs and does not require any extra computation to combine the intermediary sub-MM results.

We achieve up to 22% execution-time reduction versus GotoBLAS/ATLAS alone for a single core system and up to 19% for a two dual-core processor system. Most importantly, even for small matrices such as 1500 × 1500, our approach attains already 10% execution-time reduction and, for MM of matrices larger than 3000× 3000, it delivers performance that would correspond, for a classic
O
(
n
3
) algorithm, to faster-than-processor peak performance (i.e., our algorithm delivers the equivalent of 5 GFLOPS performance on a system with 4.4 GFLOPS peak performance and where GotoBLAS achieves only 4 GFLOPS). This is a result of the savings in operations (and thus FLOPS). Therefore, our algorithm is faster than any
classic
MM algorithms could ever be for matrices of this size. Furthermore, we present experimental evidence based on established methodologies found in the literature that our algorithm is, for a family of matrices, as accurate as the classic algorithms.
Guest Column
Authors: Viola Emanuele
Published: March 2009

This article is a unified treatment of the state-of-the-art on the fundamental challenge of exhibiting explicit functions that have small correlation with low-degree polynomials over {0 1 }. It discusses long-standing results and recent developments, related proof techniques, and connections with pseudorandom generators. It also suggests several research directions.
Teaching about threading
Authors: Fekete Alan D.
Published: March 2009

Trends in hardware and software are increasing the importance of concurrent programming, in the skill set expected of graduates. The curriculum is fairly full already, so teachers face complicated trade-offs in deciding how to incorporate additional material related to concurrency. In this paper we discuss some of the different ways to cover thread programming; we also survey the literature on this topic from the Computing Education community.
Viscosity and Glass Transition in Amorphous Oxides
Authors: Ojovan Michael I.
Published: March 2009

An overview is given of amorphous oxide materials viscosity and glass-liquid transition phenomena. The viscosity is a continuous function of temperature, whereas the glass-liquid transition is accompanied by explicit discontinuities in the derivative parameters such as the specific heat or thermal expansion coefficient. A compendium of viscosity models is given including recent data on viscous flow model based on network defects in which thermodynamic parameters of configurons—elementary excitations resulting from broken bonds—are found from viscosity-temperature relationships. Glass-liquid transition phenomena are described including the configuron model of glass transition which shows a reduction of Hausdorff dimension of bonds at glass-liquid transition.
Particle Swarm Optimization for Constrained Instruction Scheduling
Authors: Abdel-Kader Rehab F.
Published: March 2009

Instruction scheduling is an optimization phase aimed at balancing the performance‐cost tradeoffs of the design of digital systems. In this paper, a formal framework is tailored in particular to find an optimal solution to the resource‐constrained instruction scheduling problem in high‐level synthesis. The scheduling problem is formulated as a discrete optimization problem and an efficient population‐based search technique; particle swarm optimization (PSO) is incorporated for efficient pruning of the solution space. As PSO has proven to be successful in many applications in continuous optimization problems, the main contribution of this paper is to propose a new hybrid algorithm that combines PSO with the traditional list scheduling algorithm to solve the discrete problem of instruction scheduling. The performance of the proposed algorithms is evaluated on a set of HLS benchmarks, and the experimental results demonstrate that the proposed algorithm outperforms other scheduling metaheuristics and is a promising alternative for obtaining near optimal solutions to NP‐complete scheduling problem instances.
Front-Loading Sputum Microscopy Services: An Opportunity to Optimise Smear-Based Case Detection of Tuberculosis in High Prevalence Countries
Authors: Ramsay Andy , Yassin Mohammed Ahmed , Cambanis Alexis , Hirao Susumu , Almotawa Ahmad , Gammo Mohamed , Lawson Lovett , Arbide Izabel , Al-Aghbari Nasher , Al-Sonboli Najla , Sherchand Jeevan Bahadur , Gauchan Punita , Cuevas Luis Eduardo
Published: March 2009

Setting. Ethiopia, Nepal, Nigeria, and Yemen.Objective. To reduce the time to complete sputum microscopy.Design. Cross-sectional surveys enrolling 923 patients with chronic cough in the 4 countries and using similar protocols. Spot-morning-spot sputum specimens were collected. An additional sputum specimen (Xspot) was collected one hour after the first, and the yields of the first two or the three specimens collected as spot-morning-spot or spot-Xspot-morning were compared.Results. 216 patients had≥one positive smear. 210 (97%) were identified by the spot-morning-spot, and 210 (97%) were identified by the spot-Xspot-morning specimens, with 203 and 200 identified by the first 2 specimens of each approach, respectively. Neither difference was significant.Conclusions. The time to complete smear microscopy could be reduced.
Sparse Representation for Classification of Tumors Using Gene Expression Data
Authors: Hang Xiyi , Wu Fang-Xiang
Published: March 2009

Personalized drug design requires the classification of cancer patients as accurate as possible. With advances in genome sequencing and microarray technology, a large amount of gene expression data has been and will continuously be produced from various cancerous patients. Such cancer‐alerted gene expression data allows us to classify tumors at the genomewide level. However, cancer‐alerted gene expression datasets typically have much more number of genes (features) than that of samples (patients), which imposes a challenge for classification of tumors. In this paper, a new method is proposed for cancer diagnosis using gene expression data by casting the classification problem as finding sparse representations of test samples with respect to training samples. The sparse representation is computed by the l1‐regularized least square method. To investigate its performance, the proposed method is applied to six tumor gene expression datasets and compared with various support vector machine (SVM) methods. The experimental results have shown that the performance of the proposed method is comparable with or better than those of SVMs. In addition, the proposed method is more efficient than SVMs as it has no need of model selection.
Molecularly Characterised Xenograft Tumour Mouse Models: Valuable Tools for Evaluation of New Therapeutic Strategies for Secondary Liver Cancers
Authors: Mischek Daniela , Steinborn Ralf , Petznek Helga , Bichler Christoph , Zatloukal Kurt , Stürzl Michael , Günzburg Walter H. , Hohenadl Christine
Published: March 2009

To develop and evaluate new therapeutic strategies for the treatment of human cancers, well‐characterised preclinical model systems are a prerequisite. To this aim, we have established xenotransplantation mouse models and corresponding cell cultures from surgically obtained secondary human liver tumours. Established xenograft tumours were patho‐ and immunohistologically characterised, and expression levels of cancer‐relevant genes were quantified in paired original and xenograft tumours and the derivative cell cultures applying RT‐PCR‐based array technology. Most of the characteristic morphological and immunohistochemical features of the original tumours were shown to be maintained. No differences were found concerning expression of genes involved in cell cycle regulation and oncogenesis. Interestingly, cytokine and matrix metalloproteinase encoding genes appeared to be expressed differentially. Thus, the established models are closely reflecting pathohistological and molecular characteristics of the selected human tumours and may therefore provide useful tools for preclinical analyses of new antitumour strategies in vivo.
SIDH: A Game‐Based Architecture for a Training Simulator
Authors: Backlund P. , Engström H. , Gustavsson M. , Johannesson M. , Lebram M. , Sjörs E.
Published: March 2009

Game‐based simulators, sometimes referred to as “lightweight” simulators, have benefits such as flexible technology and economic feasibility. In this article, we extend the notion of a game‐based simulator by introducing multiple screen view and physical interaction. These features are expected to enhance immersion and fidelity. By utilizing these concepts we have constructed a training simulator for breathing apparatus entry. Game hardware and software have been used to produce the application. More important, the application itself is deliberately designed to be a game. Indeed, one important design goal is to create an entertaining and motivating experience combined with learning goals in order to create a serious game. The system has been evaluated in cooperation with the Swedish Rescue Services Agency to see which architectural features contribute to perceived fidelity. The modes of visualization and interaction as well as level design contribute to the usefulness of the system.
Fixed Points of Generalized Contractive Maps
Authors: Latif Abdul , Abdou Afrah A. N.
Published: March 2009

We prove some results on the existence of fixed points for multivalued generalized "Equation missing"-contractive maps not involving the extended Hausdorff metric. Consequently, several known fixed point results are either generalized or improved.
Randomized Trial of Warfarin, Aspirin, and Clopidogrel in Patients With Chronic Heart Failure
Authors: Massie Barry M. , Collins Joseph F. , Ammon Susan E. , Armstrong Paul W. , Cleland John G.F. , Ezekowitz Michael , Jafri Syed M. , Krol William F. , O'Connor Christopher M. , Schulman Kevin A. , Teo Koon , Warren Stuart R.
Published: March 2009

Background—

Chronic heart failure remains a major cause of mortality and morbidity. The role of antithrombotic therapy in patients with chronic heart failure has long been debated. The objective of this study was to determine the optimal antithrombotic agent for heart failure patients with reduced ejection fractions who are in sinus rhythm.

Methods and Results—

This prospective, randomized clinical trial of open-label warfarin (target international normalized ratio of 2.5 to 3.0) and double-blind treatment with either aspirin (162 mg once daily) or clopidogrel (75 mg once daily) had a 30-month enrollment period and a minimum of 12 months of treatment. We enrolled 1587 men and women ≥18 years of age with symptomatic heart failure for at least 3 months who were in sinus rhythm and had left ventricular ejection fraction of ≤35%. The primary outcome was the time to first occurrence of death, nonfatal myocardial infarction, or nonfatal stroke. For the primary composite end point, the hazard ratios were as follows: for warfarin versus aspirin, 0.98 (95% CI, 0.86 to 1.12;
P
=0.77); for clopidogrel versus aspirin, 1.08 (95% CI, 0.83 to 1.40;
P
=0.57); and for warfarin versus clopidogrel, 0.89 (95% CI, 0.68 to 1.16;
P
=0.39). Warfarin was associated with fewer nonfatal strokes than aspirin or clopidogrel. Hospitalization for worsening heart failure occurred in 116 (22.2%), 97 (18.5%), and 89 (16.5%) patients treated with aspirin, clopidogrel, and warfarin, respectively (
P
=0.02 for warfarin versus aspirin).

Conclusion—

The primary outcome measure and the mortality data do not support the primary hypotheses that warfarin is superior to aspirin and that clopidogrel is superior to aspirin.
Molecular Architecture of the Human Sinus Node
Authors: Chandler Natalie J. , Greener Ian D. , Tellez James O. , Inada Shin , Musa Hanny , Molenaar Peter , DiFrancesco Dario , Baruscotti Mirko , Longhi Renato , Anderson Robert H. , Billeter Rudolf , Sharma Vinod , Sigg Daniel C. , Boyett Mark R. , Dobrzynski Halina
Published: March 2009

Background—

Although we know much about the molecular makeup of the sinus node (SN) in small mammals, little is known about it in humans. The aims of the present study were to investigate the expression of ion channels in the human SN and to use the data to predict electrical activity.

Methods and Results—

Quantitative polymerase chain reaction, in situ hybridization, and immunofluorescence were used to analyze 6 human tissue samples. Messenger RNA (mRNA) for 120 ion channels (and some related proteins) was measured in the SN, a novel paranodal area, and the right atrium (RA). The results showed, for example, that in the SN compared with the RA, there was a lower expression of Na
v
1.5, K
v
4.3, K
v
1.5, ERG, K
ir
2.1, K
ir
6.2, RyR2, SERCA2a, Cx40, and Cx43 mRNAs but a higher expression of Ca
v
1.3, Ca
v
3.1, HCN1, and HCN4 mRNAs. The expression pattern of many ion channels in the paranodal area was intermediate between that of the SN and RA; however, compared with the SN and RA, the paranodal area showed greater expression of K
v
4.2, K
ir
6.1, TASK1, SK2, and MiRP2. Expression of ion channel proteins was in agreement with expression of the corresponding mRNAs. The levels of mRNA in the SN, as a percentage of those in the RA, were used to estimate conductances of key ionic currents as a percentage of those in a mathematical model of human atrial action potential. The resulting SN model successfully produced pacemaking.

Conclusions—

Ion channels show a complex and heterogeneous pattern of expression in the SN, paranodal area, and RA in humans, and the expression pattern is appropriate to explain pacemaking.
Safety of Short-Term Discontinuation of Antiplatelet Therapy in Patients With Drug-Eluting Stents
Authors: Eisenberg Mark J. , Richard Pierre R. , Libersan Danielle , Filion Kristian B.
Published: March 2009

Background—

Antiplatelet therapy is often discontinued in patients with drug-eluting stents who are undergoing surgical procedures. However, discontinuation of antiplatelet therapy is an important risk factor for late stent thrombosis. Our objective was to examine the safety of short-term discontinuation of antiplatelet therapy.

Methods and Results—

We systematically searched Medline for reported cases of late stent thrombosis and very late stent thrombosis published between January 2001 and July 2008. We restricted our search to Academic Research Consortium–defined definite cases. We identified 161 cases of late stent thrombosis or very late stent thrombosis from 84 articles (79 from case reports, 61 from registries, and 21 from randomized clinical trials). Patients had a mean age of 58.4±13.4 years, and 88% were male. A total of 19 cases occurred in patients who were receiving dual antiplatelet therapy at the time of the event. If patients stopped both antiplatelet agents simultaneously, the median time to event was 7 days. If patients had previously stopped a thienopyridine with no ill effect and subsequently stopped acetylsalicylic acid, the median time to event was also 7 days from the time of acetylsalicylic acid cessation. If the thienopyridine was stopped but acetylsalicylic acid was maintained, the median time to event was 122 days. Among the 48 patients who stopped both agents, 36 cases (75%) occurred within 10 days. Among the 94 patients who discontinued a thienopyridine but continued acetylsalicylic acid, only 6 cases (6%) occurred within 10 days.

Conclusion—

If acetylsalicylic acid therapy is maintained, short-term discontinuation of a thienopyridine may be relatively safe in patients with drug-eluting stents.
Validation-Based Sparse Gaussian Process Classifier Design
Authors: Shevade Shirish , Sundararajan S.
Published: March 2009

Gaussian processes (GPs) are promising Bayesian methods for classification and regression problems. Design of a GP classifier and making predictions using it is, however, computationally demanding, especially when the training set size is large. Sparse GP classifiers are known to overcome this limitation. In this letter, we propose and study a validation-based method for sparse GP classifier design. The proposed method uses a negative log predictive (NLP) loss measure, which is easy to compute for GP models. We use this measure for both basis vector selection and hyperparameter adaptation. The experimental results on several real-world benchmark data sets show better or comparable generalization performance over existing methods.
Where Should Educational Leadership Authors Publish to Get Noticed by the Top Journals in the Discipline?
Authors: Richardson Jayson W. , McLeod Scott
Published: March 2009

Purpose: The current study seeks to understand which journals have been recently cited by scholars publishing in the field of educational leadership (i.e., specifically publishing in Educational Administration Quarterly [ EAQ] and Journal of School Leadership [ JSL]). Method: The researchers recorded the name and number of occurrences of journals that appeared in the bibliographies of articles published in EAQ and JSL from 2000 to 2007. The total counts for EAQ and JSL were combined to reach a final count. All journals then were rank ordered according to frequency. Findings: Five main findings were noted in the current study. First, it was found that authors who contribute to these journals tend to reference a different set of periodicals compared to those that professors of educational leadership say they actually read. Second, two of the leading journals ( EAQ and JSL) in the field of educational leadership may be reaching unique audiences. Third, of the top 25 cited journals, slightly more than one third of the articles cited in EAQ and JSL from 2000 to 2007 were published in those two journals. Fourth, 4 of the top 15 most cited journals are practitioner journals. Finally, the findings show where educational leadership authors should publish to get their work noticed by top scholars in the field. Conclusion: The current study adds a valuable factor influencing authors’ choices of journals in which to publish their work: a journal’s citation frequency. The citation patterns noted in the current article will help authors consider issues of spread and replicability when seeking suitable outlets to publish their scholarly work.