bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional Genomic Identification of Genes Required for Male Gonadal Differentiation in Caenorhabditis elegans
Authors: Kalis Andrea K , Kroetz Mary B , Larson Kathleen M , Zarkower David
Published: March 2010

The Caenorhabditis elegans  somatic gonad develops from a four-cell primordium into a mature organ that differs dramatically between the sexes in overall morphology (two arms in hermaphrodites and one in males) and in the cell types comprising it. Gonadal development in C. elegans is well studied, but regulation of sexual differentiation, especially later in gonadal development, remains poorly elucidated. To identify genes involved in this process, we performed a genome-wide RNAi screen using sex-specifically expressed gonadal GFP reporters. This screen identified several phenotypic classes, including ∼70 genes whose depletion feminized male gonadal cells. Among the genes required for male cell fate specification are Wnt/β-catenin pathway members, cell cycle regulators, and genes required for mitotic spindle function and cytokinesis. We find that a Wnt/β-catenin pathway independent of extracellular Wnt ligand is essential for asymmetric cell divisions and male differentiation during gonadal development in larvae. We also find that the cell cycle regulators cdk-1 and cyb-3 and the spindle/cytokinesis regulator zen-4 are required for Wnt/β-catenin pathway activity in the developing gonad. After sex is determined in the gonadal primordium the global sex determination pathway is dispensable for gonadal sexual fate, suggesting that male cell fates are promoted and maintained independently of the global pathway during this period.
Validation of Rapid Neurodevelopmental Assessment Instrument for Under-Two-Year-Old Children in Bangladesh
Authors: Khan Naila Zaman , Muslima Humaira , Begum Dilara , Shilpi Asma Begum , Akhter Selina , Bilkis Khaleda , Begum Nasreen , Parveen Monowara , Ferdous Shamim , Morshed Romella , Batra Maneesh , Darmstadt Gary L.
Published: March 2010

OBJECTIVE:

The objective of this study was to determine the reliability and validity of a comprehensive assessment procedure for ascertaining neurodevelopmental status of children aged 0 to 24 months for use by multidisciplinary professionals in a developing country.

METHODS:

We developed the Rapid Neurodevelopmental Assessment (RNDA) to determine functional status in the following domains: primitive reflexes, gross motor, fine motor, vision, hearing, speech, cognition, behavior, and seizures. Reliability was determined for 50 children who were aged <3 months and 30 children who were aged ≥3 to 24 months and were administered the RNDA by 8 different professionals (3 physicians, 4 therapists, and 1 special teacher). Validity was determined on 34 children aged <3 months in hospital and 81 children aged ≥3 to 24 months in urban (n = 47) and rural (n = 34) community-based populations by any 1 of the 8 professionals, with simultaneous administration of the adapted Bayley Scales of Infant Development II by a psychologist as the gold standard.

RESULTS:

Mean κ coefficients of agreement among professionals in overall and individual domains in the 2 age groups ranged from good to excellent. For both younger and older children, there was good concurrent validity (ie, significantly lower mean Mental Development Index and Psychomotor Development Index scores) for children with ≥1 neurodevelopmental impairment and for children with impairments in most functional domains, compared with children with no impairments. Significantly more impairments were found in children from disadvantaged compared with socioeconomically more advantaged communities, indicating good discriminant validity.

CONCLUSIONS:

The RNDA can be used by professionals from a range of backgrounds with high reliability and validity for determining functional status of children who are younger than 2 years. The study findings have important practical implications for early identification and intervention to mitigate neurodevelopmental impairments in large populations that live in developing countries where professional expertise is sparse.
Current Pediatrician Practices in Identifying High-risk Behaviors of Adolescents
Authors: Henry-Reid Lisa M. , O'Connor Karen G. , Klein Jonathan D. , Cooper Ellen , Flynn Pat , Futterman Donna C.
Published: March 2010

OBJECTIVE:

In the United States, 15- to 24-year-olds represent ∼14% of HIV cases diagnosed in 2006 and almost 50% of the 19 million sexually transmitted infections (STIs) reported annually. This survey assessed pediatricians' practices regarding preventive health care screening, provision of reproductive health services including HIV and STI screening and counseling, and barriers to providing these services.

METHODS:

A random-sample mailed survey of 1626 US members of the American Academy of Pediatrics in 2005.A total of 752 completed questionnaires were returned (46% response rate). Analysis was limited to the 468 pediatricians who provided health supervision visits to patients who were older than 11 years.

RESULTS:

Most pediatricians discussed sexual activity at preventive care visits; similar numbers discuss abstinence (62%), condoms (61%), and STIs (61%) with slightly fewer discussing HIV (54%). Pediatricians occasionally or rarely/never discussed homosexuality/sexual identity (82%). Most (71%) identified adolescents with high-risk behaviors by clinical interviews. Approximately 30% prescribed condoms, 22% distributed condoms, and 19% provided condom demonstrations. Whereas 46% of pediatricians recommended STI tests for all sexually active teens, only 28% recommended HIV testing for this population. Hospital/clinic-based and inner-city practitioners were more likely to prescribe, provide, and demonstrate condoms and recommend HIV/STI tests for sexually active teens. The most frequently identified barrier to HIV and STI prevention counseling was lack of time.

CONCLUSIONS:

Pediatricians believed it is important to deliver reproductive health services, and most addressed adolescent sexual activity at preventive care visits but did not routinely address homosexuality/sexual identity. Counseling and testing practices varied by physician characteristics.
Placental Inflammatory Response Is Associated With Poor Neonatal Growth: Preterm Birth Cohort Study
Authors: Mestan Karen , Yu Yunxian , Matoba Nana , Cerda Sandra , Demmin Bethany , Pearson Colleen , Ortiz Katherin , Wang Xiaobin
Published: March 2010

OBJECTIVE:

We sought to determine whether placental markers of intrauterine inflammation were associated with poor weight gain among premature infants in the neonatal period.

METHODS:

We reviewed 697 preterm births prospectively enrolled as part of an ongoing molecular epidemiological study. Placental markers and serial weight gain were analyzed for premature infants who were hospitalized for ≥21 days (N = 256). Placentas were examined for maternal inflammatory response (MIR), defined as subchorionitis, chorioamnionitis, deciduitis, or free membranitis, and fetal inflammatory response (FIR), defined as inflammation extending to the umbilical cord or chorionic plate. Multivariate linear regression and stratified analyses were performed.

RESULTS:

Decreases in weight gain at day 21 were associated with the presence of either MIR or FIR (β coefficient = −4.63 ± 1.41; P = .001). The association was stronger with FIR than MIR (P for trend = .0027) and persisted in the remaining hospitalized infants at day 28 (n = 223; β coefficient = −5.53 ± 1.85; P = .0028). Mean body weights were similar among the 3 groups by corrected age of 36 weeks or discharge, whichever came first. Associations between placental inflammation and poor growth persisted among infants with prenatal corticosteroid exposure and/or neonatal complications and remained marginally significant in the nonexposed groups. Among infants without intrauterine growth restriction, significant association persisted (n = 186; β coefficient = −5.68 ± 1.56; P = .0003).

CONCLUSIONS:

Placental inflammation is associated with poor neonatal growth. MIR and FIR may be useful markers for identifying infants at risk for postnatal growth failure.
Malformations in a Chornobyl-Impacted Region
Authors: Wertelecki Wladimir
Published: March 2010

OBJECTIVE:

One of the populations most exposed to chronic low-dose radiation from Chornobyl (Chernobyl in Russian) lives in Polissia, the region representing the northern half of Rivne Province (Oblast) in Ukraine. Here the patterns and population rates of malformations are reported and possible etiologic factors and regional contrasts are explored.

PATIENTS AND METHODS:

Malformations, as defined by international standards, noted among all 96 438 births in Rivne between 2000 and 2006, were analyzed statistically. Contrasts of rates in Polissia compared with the rest of Rivne also were investigated.

RESULTS:

The overall rate of neural tube defects in Rivne is among the highest in Europe (22.2 per 10 000 live births). The rates of conjoined twins and teratomas also seem to be elevated. In Polissia, the overall rates of neural tube defects are even higher (27.0 vs 18.3, respectively; odds ratio: 1.46 [95% confidence interval: 1.13–1.93]), and the rates of microcephaly and microphthalmia may also be elevated.

CONCLUSIONS:

The malformation patterns observed suggest early disruptions of blastogenesis, manifesting as alterations of body axes, twinning, duplications, laterality, and midline formation. The results are sufficiently compelling to justify continuing and expanding this investigation of malformations in chronic low-dose radiation-impacted regions of Ukraine.
Comparative Study on Reliability of InP/InGaAs Heterojunction Bipolar Transistors with Highly Zn- and C-Doped Base Layers
Authors: Koizumi Atsushi , Oshitanai Kazuki , Lee Jaesung , Uchida Kazuo , Nozaki Shinji
Published: March 2010

The reliability of InP/InGaAs heterojunction bipolar transistors (HBTs) with highly carbon-doped and zinc-doped InGaAs base layers grown by metal-organic vapor phase epitaxy has been investigated. The Raman spectroscopy reveals that the post-growth annealing for the carbon-doped InGaAs base improves the crystallinity to become as good as that of the zinc-doped InGaAs base. However, the photoluminescence intensity remains lower than that of the zinc-doped InGaAs even after the post-growth annealing. The current gains of the carbon- and zinc-doped base InP/InGaAs HBTs are 63 and 75, respectively, and they are affected by the base crystallinity. After the 15-min current stress test, the current gains decreased by 40 and 3% from the initial current gains for zinc- and carbon-doped base HBTs, respectively, are observed. These results indicate that the carbon-doped base HBT is much more reliable than that of zinc-doped base HBT, though it has a lower current gain.
Minority Carrier Lifetime Measurement Based on Low Frequency Fluctuation
Authors: Ke Lin , Huang Sha , Chua Soo Jin , Lai Szu Cheng , Surani Bin Dolmanan
Published: March 2010

We present a novel, simple, and accurate approach based on low frequency voltage fluctuations to determine the averaged carrier lifetime in semiconductor materials and devices. This technique serves to address the limitations faced by existing techniques that use light as the excitation source for lifetime measurement. In this paper, the minority carrier lifetime is inferred from the 1/f low frequency noise profile exhibited by the device during low current operation. The current dependence of the power spectral density and its relation to minority carrier lifetime is modeled and derived directly giving a current dependent carrier lifetime. This technique is solely based on the electrical noise and no light source is required for excitation. The low frequency noise can be easily acquired without significant distortion via a signal analyzer as long as there is a sufficiently good Ohmic contact between the probe and the device under test, and that the device is sufficiently shielded from the influence of EMI. This technique has lower crosstalk, fewer fitting parameters, is low cost and allows the lifetime to be extracted directly from data collected at lower frequencies. These characteristics make our method useful in encapsulated devices, applicable on wafers and devices in
Fabrication of High Performance Organic Thin Film Transistor Arrays and Application to 5-inch Flexible Displays
Authors: Fujisaki Yoshihide , Takei Tatsuya , Nakajima Yoshiki , Sato Hiroto , Suzuki Mitsunori , Fukagawa Hirohiko , Motomura Genichi , Kumaki Daisuke , Yamamoto Toshihiro , Fujikake Hideo , Kurita Taiichiro , Tokito Shizuo
Published: March 2010

We have demonstrated a 5-inch flexible color liquid crystal display (LCD) and organic light emitting display (OLED) driven by low-voltage operation organic TFT. In order to achieve high-quality and high-resolution moving images, OTFTs with high performances such as a high mobility, high ON/OFF ratio, low sub-threshold slope (SS) and low operating voltage, are developed. We fabricated pentacene-based low-voltage operation OTFT with a Ta2O5 gate dielectric prepared at a low temperature process. The resulting OTFT array showed a high mobility of 0.3-0.4 cm2/Vs, ON/OFF ratio over 107, VTH=2.7V, and low SS=0.3 V/decade. OTFTs with solution-processable materials such as fluoropolymer gate dielectric and liquid-crystalline semiconducting polymers, PBTTT, were also investigated. Electrical characteristics and stabilities of these devices will be discussed. In the final section, we will demonstrate OTFT-driven flexible displays. Both of the flexible LC device and the OLED device were successfully integrated on the pentacene-based OTFT arrays. Printing and lamination techniques were introduced to assemble the flexible LC device. Phosphorescent polymer materials, which can be patterned by ink-jet printing, were used for emitting layer of OLED. Color moving images were successively shown on the resulting 5-inch displays using an active-matrix driving technique of the OTFT at a low driving voltage of 15V.
Ab intio Investigations of Lattice Parameters in ZnMgO Alloys
Authors: Heinemann Markus , Giar Marcel , Heiliger Christian
Published: March 2010

We perform density functional theory calculations to determine equilibrium lattice parameters of wurtzite Zn1-xMgxO alloys for Mg concentrationsxranging from 0 to 31.25 %. We use the local density approximation (LDA) as well as the generalized gradient approximation (GGA) for the exchange correlation functional. For the lattice constants a and c we find a deviation from Vegard's law and a constant unit cell volume independent of the Mg concentration.
Self-Assembly of Cylinder-Forming Block Copolymers on Ultrananocrystalline Diamond (UNCD) Thin Films for Lithographic Applications
Authors: Ramanathan Muruganathan , Darling Seth B. , Sumant Anirudha V. , Auciello Orlando
Published: March 2010

Block copolymers (BCPs) consist of two or more chemically distinct and incompatible polymer chains (or blocks) covalently bonded. Due to the incompatibility and connectivity constraints between the two blocks, diblock copolymers spontaneously self-assemble into microphase-separated nanoscale domains that exhibit ordered 0, 1, 2 or 3 dimensional morphologies at equilibrium. Commonly observed microdomain morphologies in bulk samples are periodic arrangements of lamellae, cylinders, or spheres. Block copolymer lithography refers to the use of these ordered structures in the form of thin films as templates for patterning through selective etching or deposition. The self-assembly and domain orientation of block copolymers on a given substrate is critical to realize block copolymer lithography as a tool for large throughput nanolithography applications. In this work, we survey the morphology of cylinder-forming block copolymers by atomic force microscopy (AFM). Three kind of block copolymers were studied: a) poly(styrene-block-ferrocenyldimethylsilane), PS-b-PFS b) poly(styrene-block-methylmethacrylate), PS-b-PMMA and c) poly(styrene-block-dimethylsiloxane) PS-b-PDMS. Block copolymers were dissolved in a neutral solvent for both blocks (toluene) in order to obtain solutions of various concentrations (1 and 1.5 wt %). From these solutions, films were prepared by spin casting on ultrananocrystalline diamond (UNCD) thin film substrates. Results indicate that PS-b-PFS exhibits chemical and morphological compatibility to the UNCD surface in terms of wetting and domain control. A systematic comparison of self-assembly of these polymers on silicon nitride substrates demonstrates that UNCD thin films would require pre-treatment to be considered as a substrate for BCP lithography.
Simulations of Charge Gain and Collection Efficiency from Diamond Amplifiers
Authors: Dimitrov Dimitre A. , Busby Richard , Cary John R. , Ben-Zvi Ilan , Smedley John , Chang Xiangyun , Rao Triveni , Keister Jeffrey W. , Muller Erik M. , Burrill Andrew
Published: March 2010

A promising new concept of a diamond amplified photocathode for generation of high-current, high-brightness, and low thermal emittance electron beams was recently proposed and is currently under active development. To better understand the different effects involved, we have been developing models, within the VORPAL computational framework, to simulate secondary electron generation and charge transport in diamond. The implemented models include inelastic scattering of electrons and holes for generation of electron-hole pairs, elastic, phonon, and charge impurity scattering. We will discuss these models and present results from 3D VORPAL simulations on charge gain and collection efficiency as a function of primary electron energy and applied electric field. The implemented modeling capabilities already allow us to investigate specific effects and compare simulation results with experimental data.
Structural and electronic properties of strained graphene nanoribbons modified by molecules
Authors: Urakawa T. , Shintani K.
Published: March 2010

The structural and electronic properties of graphene nanoribbons (GNRs) modified by H, CO, and NH3 molecules at their edges under uniaxial strain is investigated by means of first principles calculations. It is found the bond length of the reconstructed edge of a H-terminated GNR modified by CO is larger than those of a bare GNR, a H-terminated GNR, and a H-terminated GNR modified by NH3. It is also found the band gaps of a H-terminated GNR and a H-terminated GNR modified by CO are twice the gap of a bare GNR, and the band gaps of a bare GNR and a H-terminated GNR increase with the increase of imposed strain.
Quantum Ring Infrared Photodetector Based On Droplet Epitaxy Technique
Authors: Shao Dali , Wu Jiang , Li Zhenghua , Manasreh Omar , Kunets Vasyl P , Wang Zhiming M , Salamo Gregory J.
Published: March 2010

In this work, we design and fabricate a GaAs quantum ring infrared photodetector. The lattice matched GaAs/Al0.3Ga0.7As quantum rings are grown by using molecular beam epitaxy technique. The morphology of the quantum rings are characterized by an atomic force microscopy. Normal incident configured photodetectors are fabricated by standard photolithography. The photoresponse spectra are measured by a Fourier transform infrared spectrometer and exhibit two broad bands in visible-near-infrared and mid-infrared spectral range. Using quantum rings as absorption medium, we observed visible-near-infrared response at a temperature as high as 300 K while mid-infrared response up to 140 K.
Effective temperature inside living cells
Authors: Wilhelm Claire
Published: March 2010

The combination of active and passive microrheology using magnetic probes engulfed inside living cells demonstrates the violation of the fluctuation dissipation theorem in cells. It is proposed to quantify the deviation from the in equilibrium situation with an effective temperature. Each magnetic probe then serves as a local thermometer within the cells. The response of pairs of magnetic beads of two diameters (1 and 2.8 μm) to an oscillating magnetic field is analyzed to measure the viscoelastic complex modulus in the beads environment (active measurement). The spontaneous motion of the beads is tracked to compute their mean square displacements (passive measurement). The effective temperature is derived using an extension of the fluctuation dissipation theorem.
Statistical Phonon Transport Model of Thermal Transport in Silicon
Authors: Brown Thomas W , Hensel Edward
Published: March 2010

Thermal transport in crystalline materials at various length scales can be modeled by the Boltzmann transport equation (BTE). A statistical phonon transport (SPT) model is presented that solves the BTE in a statistical framework that incorporates a unique state-based phonon transport methodology. Anisotropy of the first Brillouin zone (BZ) is captured by utilizing directionally-dependent dispersion curves obtained from lattice dynamics calculations. A rigorous implementation of phonon energy and pseudo-momentum conservation is implemented in the ballistic thermal transport regime for a homogeneous silicon nanowire with adiabatic specular boundary conditions.
Tackling Science Communication with REU Students: A Formative Evaluation of a Collaborative Approach
Authors: Alpert Carol Lynn , Levine Eliot , Barry Carol F. , Isaacs Jacqueline , Fiorentino Alex , Hollar Kathryn , Thate Karine
Published: March 2010

This paper reports on a multi-faceted evaluation of science communication workshops conducted during the summer of 2009 with Research Experience for Undergraduate (REU) students from the Center for High-rate Nanomanufacturing and the Harvard University School of Engineering and Applied Sciences, in a partnership between the Museum of Science, Boston Strategic Projects department and faculty from the Nanoscale Science and Engineering Centers headquartered at Harvard and at Northeastern Universities. The workshops were shown to (1) increase student interest in exploring and understanding the broader impacts of research, and (2) increase student knowledge, confidence and practice of communication skills for both professional and non-professional audiences.
Study on the Effects of Type I Collagen Combined with Noncollagenous Proteins on Hydroxyapatite Formation in vitro using SPM and GIXD
Authors: Ba Xiaolan , DiMasi Elaine , Rafailovich Miriam H
Published: March 2010

The effects of the components of extracellular matrix on the bone formation and the kinetics of crystal growth of calcium phosphate have remained unknown. In this paper, we reported a method to investigate the role of Type I collagen and the interactions with other ECM proteins such as fibronectin and elastin during biomimic mineralization process in vitro. The early stage of mineralization was characterized by scanning probe microscopy (SPM) and shear modulation force microscopy (SMFM). The late stage of mineralization was investigated by synchrotron grazing incident x-ray diffraction (GIXD). The results demonstrate the cooperative interaction between type I collagen and noncollagenous proteins such as fibronectin or elastin could be essential for the biomineralization.
Prevalence and Correlates of Mental Disorders in a School-Survey Sample
Authors: Faravelli Carlo , Lo Sauro Carolina , Castellini Giovanni , Ricca Valdo , Pallanti Stefano
Published: March 2010

Background:

Most of the adult mental disorders have their origins early in life. As the epidemiology of childhood psychiatric disorder in Italy has not been extensively investigated, we have evaluated the prevalence of mental disorders and their association with socio-familiar variables in a representative sample of children aged 6 to 11.

Method:

The study was conducted on a school- sample of 1028 children, aged 6 to 11, attending 12 primary schools in Florence (Italy). The diagnoses were made according to DSM IV diagnostic criteria, integrated by the description of each symptom, using specially trained teachers as lay-interviewers. Odds ratios with 95% C.I. chi squares and a stepwise binary logistic analysis have been performed.

Results:

Nine hundred ninety nine children (506 males; 493 females) were studied. Of them, 10.5% received a psychiatric diagnosis, with a higher prevalence in males (66.7% vs.33.3, p<0.01). The most prevalent groups of mental disorders were the behavioural/impulse control (7.2%) and anxiety (6.4%) disorders. Attention Deficit with Hyperactivity Disorder was the most represented diagnosis (5.6% of the children). All the other mental disorders were relatively rare, with only separation anxiety and overanxious disorder exceeding 1% prevalence.

Male gender, organic disease, having mother divorced, not present or dead, attending school full-time, cohabitation in the family were associated with an increased risk for any childhood mental disorder.

Conclusions:

About one in ten children aged 6-11 suffers from a mental disorder. Male gender, loss of mother and lower socio-economic status are associated with mental disorders in children. Further long-term prospective studies are needed, in order to clarify the epidemiological and psychopathological relationships between childhood and adult mental disorders.
Personality and Psychopathology: a Theory-Based Revision of Eysenck’s PEN Model
Authors: van Kampen Dirk
Published: March 2010

The principal aim of this paper is to investigate whether it is possible to create a personality taxonomy of clinical relevance out of Eysenck’s original PEN model by repairing the various shortcomings that can be noted in Eysenck’s personality theory, particularly in relation to P or Psychoticism. Addressing three approaches that have been followed to answer the question ‘which personality factors are basic?’, arguments are listed to show that particularly the theory-informed approach, originally defended by Eysenck, may lead to scientific progress. However, also noting the many deficiencies in the nomological network surrounding P, the peculiar situation arises that we adhere to Eysenck’s theory-informed methodology, but criticize his theory. These arguments and criticisms led to the replacement of P by three orthogonal and theory-based factors, Insensitivity (S), Orderliness (G), and Absorption (A), that together with the dimensions E or Extraversion and N or Neuroticism, that were retained from Eysenck’s PEN model, appear to give a comprehensive account of the main vulnerability factors in schizophrenia and affective disorders, as well as in other psychopathological conditions.
Dynamic Failure Properties of the Porcine Medial Collateral Ligament-Bone Complex for Predicting Injury in Automotive Collisions
Authors: Peck Louis , Billiar Kristen , Ray Malcolm
Published: March 2010

The goal of this study was to model the dynamic failure properties of ligaments and their attachment sites to facilitate the development of more realistic dynamic finite element models of the human lower extremities for use in automotive collision simulations. Porcine medial collateral ligaments were chosen as a test model due to their similarities in size and geometry with human ligaments. Each porcine medial collateral ligament-bone complex (n = 12) was held in a custom test fixture placed in a drop tower to apply an axial impulsive impact load, applying strain rates ranging from 0.005 s-1 to 145 s-1. The data from the impact tests were analyzed using nonlinear regression to construct model equations for predicting the failure load of ligament-bone complexes subjected to specific strain rates as calculated from finite element knee, thigh, and hip impact simulations. The majority of the ligaments tested failed by tibial avulsion (75%) while the remaining ligaments failed via mid-substance tearing. The failure load ranged from 384 N to 1184 N and was found to increase with the applied strain rate and the product of ligament length and cross-sectional area. The findings of this study indicate the force required to rupture the porcine MCL increases with the applied bone-to-bone strain rate in the range expected from high speed frontal automotive collisions.
Structural Causes of Right Bundle Branch Block—Time for a Closer Look?
Authors: Ker James
Published: March 2010

Right bundle branch block is an electrocardiographic phenomenon with specific criteria.

Currently, two specific forms of right bundle branch block are acknowledged, a proximal and a distal variant. A vast array of pathologies can cause proximal, distal or even combined forms of right bundle branch block.

In this study it is suggested that a third type of right bundle branch block exist: one caused by a subaortic muscular tendon in the left ventricle, leading to an increased velocity of conduction in the left ventricle, with a resultant “relative” right bundle branch block. It is concluded that it is necessary (and time) to take a closer look at endoventricular structures in the assessment of structural causes of right bundle branch block.
Treatment of Infected Hip Arthroplasty
Authors: Hernigou Philippe , Flouzat-Lachianette C.-H. , Jalil R. , Uirassu Batista Sobrinho , Guissou I. , Poignard A.
Published: March 2010

The clinical outcomes of a consecutive series of deep total joint infections treated with a prosthesis retaining protocol were reviewed. The treatment of deep periprosthetic joint infections is challenging. In recent years, two-stage exchange arthroplasty has emerged as the gold standard for successful elimination of infection. With success rates averaging 82% to 96%, this treatment method has both the highest and most consistent rate of infection eradication. Another alternative in the treatment of the deep periprosthetic infection is the single-stage exchange arthroplasty. Successful eradication of infection after single-stage exchange arthroplasty has been reported to average from 60% to 83% after total hip infections. While both the single and two-stage exchange arthroplasty are viable treatment options, they are associated with negative factors such as they are time consuming, expensive, and may entail a 6- to 12-week period with a minimally functioning extremity after prosthesis removal. This paper reports the general principles of management, the treatment of acute infection occurring in the postoperative period or later, and the treatment of chronic infection by exchange arthroplasty or resection arthroplasty.
The Development and Implementation of an Outreach Program to Identify Acute and Recent HIV Infections in New York City
Authors: Silvera Richard , Stein Dylan , Hutt Richard , Hagerty Robert , Daskalakis Demetre , Valentine Fred , Marmor Michael
Published: March 2010

Introduction: Since 2004, the authors have been operating First Call NYU, an outreach program to identify acute and recent HIV infections, also called primary HIV infections, among targeted at-risk communities in the New York City (NYC) metropolitan area.

Materials and Methodology: First Call NYU employed mass media advertising campaigns, outreach to healthcare providers in NYC, and Internet-based efforts including search engine optimization (SEO) and Internet-based advertising to achieve these goals.

Results: Between October 2004 and October 2008, 571 individuals were screened through this program, leading to 446 unique, in-person screening visits. 47 primary HIV infections, including 14 acute and 33 recent HIV infections, were identified.

Discussion: Internet and traditional recruitment methods can be used to increase self-referrals for screening following possible exposure to HIV.

Conclusion: Community education of at-risk groups, with the goal of increased self-diagnosis of possible acute HIV infection, may be a useful addition to traditional efforts to identify such individuals.
Feasibility of a Population Based Survey on HIV Prevalence in Barbados, and Population Preference for Sample Identification Method
Authors: Adams O. Peter , Carter Anne O.
Published: March 2010

Objective:

To predict response rate and validity of a population-based HIV prevalence survey in Barbados using oral fluid, and the method of sample identification preferred by participants.

Methods:

Persons age 18 to 35 randomly selected from the voters’ register to participate in a study of the prevalence of chlamydia and gonorrhoea (STI) were invited to answer a questionnaire.

Results:

Of 496 persons selected for the STI study, 88 did not participate, and a further 10 did not answer the questionnaire, leaving 398 respondents. 329 persons or 66% (60% men, 73% women, p = 0.003) of the original 496 persons said that they would be willing to take part in an HIV survey using oral fluid.

People indicating willingness to take part in an HIV survey did not differ significantly from non-respondents and those indicating unwillingness to participate by a number of demographic and STI risk factors including age, education level, partnership status, number of partners, condom use, drug use, and STI infection status.

For persons willing to participate in a HIV survey, confidential linked sample identification was acceptable to 99.0% (95% CI ± 1.0), and unlinked identification to 1.6% (95% CI ± 1.3).

Conclusion:

The HIV prevalence estimated by a linked survey would have a reasonable response rate and be valid, as likelihood of participation is not related to infection risk.
Evaluation of Habitat Suitability Models for Forest Passerines Using Demographic Data
Authors: RITTENHOUSE CHADWICK D. , THOMPSON FRANK R. , DIJAK WILLIAM D. , MILLSPAUGH JOSHUA J. , CLAWSON RICHARD L.
Published: March 2010

ABSTRACT Habitat suitability is often used as a surrogate for demographic responses (i.e., abundance, survival, fecundity, or population viability) in the application of habitat suitability index (HSI) models. Whether habitat suitability actually relates to demographics, however, has rarely been evaluated. We validated HSI models of breeding habitat suitability for wood thrush (Hylocichla mustelina) and yellow‐breasted chat (Icteria virens) in Missouri, USA. First, we evaluated HSI models as a predictor of 3 demographic responses: within‐site territory density, site‐level territory density, and nest success. We demonstrated a link between HSI values and all 3 types of demographic responses for the yellow‐breasted chat and site‐level territory density for the wood thrush. Second, we evaluated support for models containing HSI values, models containing measured habitat features (e.g., tree age, tree species, ecological land type), and models containing management treatments (e.g., even‐aged and uneven‐aged forest regeneration treatments) for each demographic response using model selection. Models containing HSI values received more support, in general, than models containing only habitat features or management treatments for all 3 types of wildlife response. The assumption that changes in habitat suitability represent wildlife demographic response to vegetation change is supported by our models. However, differences in species ecology may contribute to the degree to which HSI values are related to specific demographic responses. We recommend validation of HSI models with the particular demographic data of interest (i.e., density, productivity) to increase confidence in the model used for conservation planning.
Evaluation of Root‐n Bandwidth Selectors for Kernel Density Estimation
Authors: STEURY TODD D. , MCCARTHY JOHN E. , ROTH TIMOTHY C. , LIMA STEVEN L. , MURRAY DENNIS L.
Published: March 2010

ABSTRACT  The kernel density estimator is used commonly for estimating animal utilization distributions from location data. This technique requires estimation of a bandwidth, for which ecologists often use least‐squares cross‐validation (LSCV). However, LSCV has large variance and a tendency to under‐smooth data, and it fails to generate a bandwidth estimate in some situations. We compared performance of 2 new bandwidth estimators (root‐n) versus that of LSCV using simulated data and location data from sharp‐shinned hawks (Accipter striatus) and red wolves (Canis rufus). With simulated data containing no repeat locations, LSCV often produced a better fit between estimated and true utilization distributions than did root‐n estimators on a case‐by‐case basis. On average, LSCV also provided lower positive relative error in home‐range areas with small sample sizes of simulated data. However, root‐n estimators tended to produce a better fit than LSCV on average because of extremely poor estimates generated on occasion by LSCV. Furthermore, the relative performance of LSCV decreased substantially as the number of repeat locations in the data increased. Root‐n estimators also generally provided a better fit between utilization distributions generated from subsamples of hawk data and the local densities of locations from the full data sets. Least‐squares cross‐validation generated more unrealistically disjointed estimates of home ranges using real location data from red wolf packs. Most importantly, LSCV failed to generate home‐range estimates for >20% of red wolf packs due to presence of repeat locations. We conclude that root‐n estimators are superior to LSCV for larger data sets with repeat locations or other extreme clumping of data. In contrast, LSCV may be superior where the primary interest is in generating animal home ranges (rather than the utilization distribution) and data sets are small with limited clumping of locations.
Raptor Electrocution Rates for a Utility in the Intermountain Western United States
Authors: LEHMAN ROBERT N. , SAVIDGE JULIE A. , KENNEDY PATRICIA L. , HARNESS RICHARD E.
Published: March 2010

ABSTRACT We estimated electrocution rates for raptors and common ravens (Corvus corax) for the Moon Lake Electrical Association in northeastern Utah and northwestern Colorado, USA. From July 2001 to May 2003, we conducted mortality searches at randomly selected distribution line segments and poles within 3 regions, but rate estimates (0.0036–0.0112 deaths/pole/yr) may have been biased by the effects of scavengers and by long sampling intervals (≥ 3 months), which prevented us from determining the cause of death for most birds because of advanced decay. In 2002–2003, we conducted carcass removal experiments in the Rangely Oil Field (ROF) in northwestern Colorado to estimate scavenging effects, and in 2003–2004, we reduced sampling intervals to 1 month and searched for dead birds at all distribution poles in the ROF. The shorter sampling interval nearly tripled the number of birds suitable for necropsy, but we were still unable to establish cause of death for >40% of our sample. Instead of eliminating the unknowns from rate estimates, we estimated minimum annual electrocution rates using only confirmed electrocutions and maximum annual electrocution rates based on all available mortalities, including mortalities without known causes. Golden eagles (Aquila chrysaetos) accounted for 63% of dead birds found in 2003–2004, but they were removed by scavengers at rates well below hawks and owls (6.8% vs. 55.6%). We compared maximum rates for the ROF in 2003–2004 with the rates estimated from a survey conducted at the same poles in 1999 to assess the effects of retrofitting conducted by Moon Lake from 1999 to 2003. Electrocution rates in 2003–2004 were 47% lower than those in 1999. Raptor densities in the ROF did not change during our study, suggesting the reduction was not the result of changes in raptor populations. However, estimates of raptor densities in 1999 were not available, and we cannot be sure that numbers of birds using the oil field in 1999 were similar to those in 2003–2004. Our research emphasizes the difficulties of estimating electrocution rates precisely but suggests that utilities will have the greatest effect on mortality by monitoring power lines at large scales and focusing subsequent mitigation efforts in areas that pose the greatest risk to the greatest number of birds.
Body Size Variations in Caribou Ecotypes and Relationships With Demography
Authors: COUTURIER SERGE , OTTO ROBERT D. , COTE STEEVE D. , LUTHER GLENN , MAHONEY SHANE P.
Published: March 2010

ABSTRACT In many vertebrates size is one of the most influential and variable individual characteristics and a strong determinant of reproductive success. Body size is generally density dependent and decreases when intraspecific competition increases. Frequent and long‐distance movements increase energy expenditures and, therefore, may also influence body size, particularly in highly mobile species. Caribou (Rangifer tarandus, also known as reindeer) exhibit tremendous variation in size and movements and thus represent an excellent candidate species to test the relationships between body size, population size, and movements. We analyzed body measurements of adult female caribou from 7 herds of the Québec‐Labrador Peninsula, Canada, and we related their morphology to population size, movements, and annual ranges. The herds represented 3 ecotypes (migratory, montane, and sedentary). Ecotypes and herds differed in size (length), shape (roundness), and movements. The sedentary ecotype was larger and moved 4 to 7 times less than the migratory ecotype in the 1990s. At the start of a demographic growth period in the early 1960s, migratory caribou from the Rivière‐George (hereafter George) herd had longer mandibles than caribou of the sedentary ecotype. Mandible length in the George herd declined in the 1980s after rapid population growth, while individuals performed extensive movements and the herd's annual range increased. Migratory caribou then became shorter than sedentary caribou. After the George herd decline in the 1990s, mandible length increased again near levels of the 1980s. Caribou from the migratory Rivière‐aux‐Feuilles herd later showed a similar decline in mandible length during a period of population growth, associated with longer movements and increasing annual range. We hypothesize that the density‐dependent effect observed on body size might have been exerted through summer habitat degradation and movement variations during herd growth. Our study has 2 important implications for caribou management: the distinctiveness of different populations and ecotypes, and the correlations between population trajectories and changes in body condition and habitat.
Using Genetic Tools to Track Desert Bighorn Sheep Colonizations
Authors: EPPS CLINTON W. , WEHAUSEN JOHN D. , PALSBØLL PER J. , MCCULLOUGH DALE R.
Published: March 2010

ABSTRACT  Understanding colonization is vital for managing fragmented populations. We employed mitochondrial DNA haplotypes and 14 microsatellite (nuclear DNA) markers to infer the origins of newly established populations of desert bighorn sheep (Ovis canadensis nelsoni) and to assess loss of genetic diversity during natural colonizations. We used haplotype distribution, F‐statistics, Bayesian population clustering, and assignment tests to infer source populations for 3 recent colonies and identified a previously undetected colonization from multiple source populations. Allelic richness declined in 3 of 4 colonies in comparison to the primary source populations, but not as much as has been reported for translocated populations. Heterozygosity declined in only one colony. We also demonstrated that both native and translocated desert bighorn sheep have naturally recolonized empty habitats and suggest that colonization may partially offset population extinction in the region as long as connectivity is maintained. Genetic techniques and mitochondrial DNA haplotypes we described will allow managers to determine the origins of future colonizations by bighorn sheep in California, USA, and prioritize protection of linkages between known sources and colonies.
Landscape and Vegetation Effects on Avian Reproduction on Bottomland Forest Restorations
Authors: TWEDT DANIEL J. , SOMERSHOE SCOTT G. , HAZLER KIRSTEN R. , COOPER ROBERT J.
Published: March 2010

ABSTRACT Forest restoration has been undertaken on >200,000 ha of agricultural land in the Mississippi Alluvial Valley, USA, during the past few decades. Decisions on where and how to restore bottomland forests are complex and dependent upon landowner objectives, but for conservation of silvicolous (forest‐dwelling) birds, ecologists have espoused restoration through planting a diverse mix of densely spaced seedlings that includes fast‐growing species. Application of this planting strategy on agricultural tracts that are adjacent to extant forest or within landscapes that are predominately forested has been advocated to increase forest area and enhance forested landscapes, thereby benefiting area‐sensitive, silvicolous birds. We measured support for these hypothesized benefits through assessments of densities of breeding birds and reproductive success of 9 species on 36 bottomland forest restoration sites. Densities of thamnic (shrub‐scrub dwelling) and silvicolous birds, such as yellow‐breasted chat (Icteria virens), indigo bunting (Passerina cyanea), and white‐eyed vireo (Vireo griseus) were positively associated with 1) taller trees, 2) greater stem densities, and 3) a greater proportion of forest within the landscape, whereas densities of birds associated with grasslands, such as dickcissel (Spiza americana) and red‐winged blackbird (Agelaius phoeniceus), were negatively associated with these variables. Vegetation structure, habitat edge, and temporal effects had greater influence on nest success than did landscape effects. Taller trees, increased density of woody stems, greater vegetation density, and more forest within the landscape were often associated with greater nest success. Nest success of grassland birds was positively related to distance from forest edge but, for thamnic birds, success was greater near edges. Moreover, nest success and estimated fecundity of thamnic species suggested their populations are self‐sustaining on forest restoration sites, whereas these sites are likely population sinks for grassland and open‐woodland species. We recommend restoration strategies that promote rapid development of dense forest stands within largely forested landscapes to recruit breeding populations of thamnic and silvicolous birds that have reproductive success sufficient to sustain their populations.
Agricultural Seed Biomass for Migrating and Wintering Waterfowl in the Southeastern United States
Authors: FOSTER MELISSA A. , GRAY MATTHEW J. , KAMINSKI RICHARD M.
Published: March 2010

ABSTRACT  Waterfowl frequently acquire high‐energy agricultural seeds in harvested and unharvested croplands during migration and winter. Estimates of agricultural seed biomass in harvested and unharvested corn, soybean, and grain sorghum fields do not exist or are outdated for the southeastern United States. Therefore, we estimated seed biomass in 105 harvested and 59 unharvested corn, soybean, and grain sorghum fields across 4 climate regions in Tennessee, USA, from September through January 2006 and 2007. We also used estimates of seed biomass to calculate duck‐energy days (DEDs) in December and January when migratory waterfowl abundance peaks in the southeastern United States. Mean biomass of corn, soybean, and grain sorghum seed in harvested fields declined 239 kg/ha to 39 kg/ha, 118 kg/ha to 26 kg/ha, and 392 kg/ha to 19 kg/ha, respectively, from postharvest to January. Continuous monthly rates of decline were 64% for corn, 84% for soybean, and 74% for grain sorghum. Agricultural seed biomass in harvested corn and grain sorghum fields dropped below the waterfowl giving‐up density (i.e., 50 kg/ha) in 3 months; soybean dropped below this threshold 1 month postharvest. Mean DEDs/ha in harvested corn, soybean, and grain sorghum fields were low (274, 90, and 27, respectively) in January, and DEDs were zero in >85% of fields. In unharvested corn, soybean, and grain sorghum fields, mean DEDs/ha in January were high (69,000, 18,000, and 26,000, respectively), and continuous rates of decline (3%, 7%, and 18%, respectively) were much lower than for harvested crops. Waterfowl biologists in the Southeast should use our estimates of agricultural seed biomass in DED calculations. We also recommend that biologists provide unharvested grain fields and natural wetlands for migrating and wintering waterfowl because seed resources are low in harvested agricultural fields.