bluuebunny/crossref_metadata_2025_split huggingface dataset:
Developmental adjustments of house sparrow (Passer domesticus)nestlings to diet composition
Authors: Brzęk Paweł , Kohl Kevin , Caviedes-Vidal Enrique , Karasov William H. 
Published: April 2009

SUMMARYHouse sparrow nestlings are fed primarily on insects during the first 3 days of their life, and seeds become gradually more important afterwards. We tested whether developmental changes in size and functional capacity of the digestive tract in young house sparrows are genetically hard-wired and independent of diet, or can be modified by food type. Under laboratory conditions, we hand-fed young house sparrows with either a starch-free insect-like diet, based mainly on protein and fat, or a starch-containing diet with a mix of substrates similar to that offered to older nestlings in natural nests when they are gradually weaned from an insect to a seed diet. Patterns of overall development in body size and thermoregulatory ability, and in alimentary organ size increase, were relatively similar in house sparrow nestlings developing on both diets. However, total intestinal maltase activity, important in carbohydrate breakdown, was at least twice as high in house sparrow nestlings fed the starch-containing diet (P&lt;0.001). The change in maltase activity of nestlings was specific, as no change occurred in aminopeptidase-N activity in the same tissues. There was no significant diet effect on digesta retention time, but assimilation efficiency for radiolabeled starch tended to be higher (P=0.054) in nestlings raised on starch-containing diet. Future studies must test whether the diet-dependent increase in maltase activity during development is irreversible or reversible, reflecting, respectively, a developmental plasticity or a phenotypic flexibility.
Wing and body motion during flight initiation inDrosophilarevealed by automated visual tracking
Authors: Fontaine Ebraheem I. , Zabala Francisco , Dickinson Michael H. , Burdick Joel W. 
Published: April 2009

SUMMARYThe fruit fly Drosophila melanogaster is a widely used model organism in studies of genetics, developmental biology and biomechanics. One limitation for exploiting Drosophila as a model system for behavioral neurobiology is that measuring body kinematics during behavior is labor intensive and subjective. In order to quantify flight kinematics during different types of maneuvers, we have developed a visual tracking system that estimates the posture of the fly from multiple calibrated cameras. An accurate geometric fly model is designed using unit quaternions to capture complex body and wing rotations, which are automatically fitted to the images in each time frame. Our approach works across a range of flight behaviors, while also being robust to common environmental clutter. The tracking system is used in this paper to compare wing and body motion during both voluntary and escape take-offs. Using our automated algorithms, we are able to measure stroke amplitude, geometric angle of attack and other parameters important to a mechanistic understanding of flapping flight. When compared with manual tracking methods, the algorithm estimates body position within 4.4±1.3%of the body length, while body orientation is measured within 6.5±1.9 deg. (roll), 3.2±1.3 deg. (pitch) and 3.4±1.6 deg. (yaw) on average across six videos. Similarly, stroke amplitude and deviation are estimated within 3.3 deg. and 2.1 deg., while angle of attack is typically measured within 8.8 deg. comparing against a human digitizer. Using our automated tracker, we analyzed a total of eight voluntary and two escape take-offs. These sequences show that Drosophila melanogaster do not utilize clap and fling during take-off and are able to modify their wing kinematics from one wingstroke to the next. Our approach should enable biomechanists and ethologists to process much larger datasets than possible at present and, therefore, accelerate insight into the mechanisms of free-flight maneuvers of flying insects.
Novel vocal repertoire and paired swimbladders of the three-spined toadfish,Batrachomoeus trispinosus: insights into the diversity of the Batrachoididae
Authors: Rice Aaron N. , Bass Andrew H. 
Published: April 2009

SUMMARYToadfishes (Teleostei: Batrachoididae) are one of the best-studied groups for understanding vocal communication in fishes. However, sounds have only been recorded from a low proportion of taxa within the family. Here, we used quantitative bioacoustic, morphological and phylogenetic methods to characterize vocal behavior and mechanisms in the three-spined toadfish, Batrachomoeus trispinosus. B. trispinosus produced two types of sound: long-duration `hoots' and short-duration `grunts' that were multiharmonic, amplitude and frequency modulated, with a dominant frequency below 1 kHz. Grunts and hoots formed four major classes of calls. Hoots were typically produced in succession as trains, while grunts occurred either singly or as grunt trains. Aside from hoot trains, grunts and grunt trains, a fourth class of calls consisted of single grunts with acoustic beats,apparently not previously reported for individuals from any teleost taxon. Beats typically had a predominant frequency around 2 kHz with a beat frequency around 300 Hz. Vocalizations also exhibited diel and lunar periodicities. Spectrographic cross-correlation and principal coordinates analysis of hoots from five other toadfish species revealed that B. trispinosus hoots were distinct. Unlike any other reported fish, B. trispinosus had a bilaterally divided swimbladder, forming two separate swimbladders. Phylogenetic analysis suggested B. trispinosus was a relatively basal batrachoidid, and the swimbladder and acoustic beats were independently derived. The swimbladder in B. trispinosus demonstrates that toadfishes have undergone a diversification of peripheral sonic mechanisms,which may be responsible for the concomitant innovations in vocal communication, namely the individual production of acoustic beats as reported in some tetrapods.
Optimal shape design of shoulder fillets for flat and round bars under various loadings
Authors: Sonmez F O 
Published: April 2009

Fillets are usually the most critical regions in mechanical parts especially under fatigue loading, considering that an increase in the maximum stress level considerably shortens the fatigue life of a part. The aim of this study is to find the best shape for a fillet in a shouldered shaft or plate so that the maximum equivalent stress has the lowest possible value. Optimization is achieved using a stochastic global search algorithm called the direct search simulated annealing. The boundary is defined using spline curves passing through a number of key points. The method is also applicable to shape optimization problems in which geometric constraints are imposed and, for this reason, tangential stress is not uniform along the optimal fillet boundary. Optimal shapes are obtained for flat and round bars subject to axial, bending, torsional, or combined loads. The results show that stress concentration factors close to one can be achieved even for bars with significant variations in cross-section. Besides, the region occupied by the optimum fillets is much smaller in comparison to circular or elliptical ones.
Robust control of the pressure in a control-cylinder with direct drive valve for the variable displacement axial piston pump
Authors: Park S-H , Lee J-M , Kim J-S 
Published: April 2009

To achieve energy-efficient hydraulic systems, an accurate flowrate and pressure required by a load should be supplied to the systems. The discharge flow from the variable displacement swash-plate type axial piston pump is mainly determined by the angle of the swash-plate and it is adjusted by controlling the pressure in the control cylinder, which is a mechanical regulator for the swash-plate. In this paper, a robust pressure control system of the control cylinder using a direct drive valve is proposed to control the discharge flow from the variable displacement swash-plate type axial piston pump precisely. In order to design a robust pressure control system, a mathematical model of a pressure control system is derived and system parameters are identified by using the signal-compression method. Also, the sliding mode controller is designed based on the identified mathematical model to guarantee the control performance of the pressure control system. Experiments verified the satisfactory performance of the proposed pressure control system that uses a direct drive even with non-linearity and uncertainties such as flow characteristics, unknown discharge coefficient of the valve orifice, variation of the bulk-modulus, leakage, and disturbance induced by the pressure fluctuation in the pressure control system.
Factor II- and factor Xa-inhibitors for prevention and treatment of thromboses / Faktor II- und Faktor Xa-Inhibitoren in der Prävention und Therapie von Thrombosen
Authors: Orth Matthias 
Published: April 2009

Abstract
The desired properties of an ideal anticoagulant should be reliable action, a defined, selective mode of action, a wide therapeutic window, and predictable pharmacokinetics. Numerous new substances were developed as a substitute for oral anticoagulants and heparins. Owing to their superiority in clinical studies, some of these drugs have already been approved. The hemostaseological laboratory is now challenged to detect a sufficient anticoagulation while avoiding bleeding by overdosing. The purpose of this review is to describe novel anticoagulants in current use and the possible tests for drug monitoring in heparin-induced thrombocytopenia and in the perioperative prevention of thromboses.
Drug Use and High-Risk Sexual Behaviors Among African American Men Who Have Sex With Men and Men Who Have Sex With Women
Authors: Browne Dorothy C. , Clubb Patricia A. , Wang Yan , Wagner Fernando 
Published: April 2009

Objectives. We investigated covariates related to risky sexual behaviors among young African American men enrolled at historically Black colleges and universities (HBCUs). Methods. Analyses were based on data gathered from 1837 male freshmen enrolled at 34 HBCUs who participated in the 2001 HBCU Substance Use Survey. The covariates of risky sexual behavior assessed included condom nonuse, engaging in sexual activity with multiple partners, and history of a sexually transmitted disease. Results. Young Black men who had sex with men were more likely to engage in risky sexual behaviors than were young men who had sex with women. Two additional factors, early onset of sexual activity and consumption of alcohol or drugs before sexual activity, were independently associated with modestly higher odds of sexual risk behaviors. Conclusions. Services focusing on prevention of sexually transmitted diseases should be provided to all male college students, regardless of the gender of their sexual partners. Such a general approach should also address drug and alcohol use before sexual activity.
Childhood Sexual Abuse and the Sociocultural Context of Sexual Risk Among Adult Latino Gay and Bisexual Men
Authors: Arreola Sonya Grant , Neilands Torsten B. , Díaz Rafael 
Published: April 2009

Objectives. We sought to examine the relationships among childhood sexual abuse, social discrimination, psychological distress, and HIV-risk among Latino gay and bisexual men in the United States.Methods. Data were from a probability sample of 912 men from Miami, FL; Los Angeles, CA; and New York, NY. We used logistic regression and path analyses to examine direct and indirect effects of childhood sexual abuse on psychological distress and sexual risk behavior.Results. We found a 15.8% (95% confidence interval = 12.3%, 19.2%) prevalence of childhood sexual abuse. Not having sex before age 16 years and having consensual sex before age 16 years did not differ from each other in predicting any of the outcomes of interest. Forced sex was associated with a significantly increased risk for all outcomes. A path analyses yielded direct effects of childhood sexual abuse and exposure to homophobia during childhood and during adulthood on psychological distress and indirect effects on risky sexual behavior.Conclusions. HIV-risk patterns among Latino gay and bisexual men are related to childhood sexual abuse and a social context of discrimination, which combined lead to symptoms of psychological distress and participation in risky sexual situations that increase risky sexual behaviors associated with HIV acquisition.
Accessing Social Networks With High Rates of Undiagnosed HIV Infection: The Social Networks Demonstration Project
Authors: Kimbrough Lisa W. , Fisher Holly E. , Jones Kenneth T. , Johnson Wayne , Thadiparthi Sekhar , Dooley Samuel 
Published: April 2009

Objectives. We evaluated the use of social networks to reach persons with undiagnosed HIV infection in ethnic minority communities and link them to medical care and HIV prevention services. Methods. Nine community-based organizations in 7 cities received funding from the Centers for Disease Control and Prevention to enlist HIV-positive persons to refer others from their social, sexual, or drug-using networks for HIV testing; to provide HIV counseling, testing, and referral services; and to link HIV-positive and high-risk HIV-negative persons to appropriate medical care and prevention services. Results. From October 1, 2003, to December 31, 2005, 422 recruiters referred 3172 of their peers for HIV services, of whom 177 were determined to be HIV positive; 63% of those who were HIV-positive were successfully linked to medical care and prevention services. The HIV prevalence of 5.6% among those recruited in this project was significantly higher than the approximately 1% identified in other counseling, testing, and referral sites funded by the Centers for Disease Control and Prevention. Conclusions. This peer-driven approach is highly effective and can help programs identify persons with undiagnosed HIV infection in high-risk networks.
Structural and Social Contexts of HIV Risk Among African Americans
Authors: Friedman Samuel R. , Cooper Hannah L. F. , Osborne Andrew H. 
Published: April 2009

HIV continues to be transmitted at unacceptably high rates among African Americans, and most HIV-prevention interventions have focused on behavioral change. To theorize additional approaches to HIV prevention among African Americans, we discuss how sexual networks and drug-injection networks are as important as behavior for HIV transmission. We also describe how higher-order social structures and processes, such as residential racial segregation and racialized policing, may help shape risk networks and behaviors. We then discuss 3 themes in African American culture—survival, propriety, and struggle—that also help shape networks and behaviors. Finally, we conclude with a discussion of how these perspectives might help reduce HIV transmission among African Americans.
Effects of Written Informed Consent Requirements on HIV Testing Rates: Evidence From a Natural Experiment
Authors: Wing Coady 
Published: April 2009

Objectives. I evaluated the effects of written informed consent requirements on HIV testing rates in New York State to determine whether such consent creates barriers that discourage HIV testing. Methods. New York streamlined its HIV testing consent procedures on June 1, 2005. If written informed consent creates barriers to HIV testing, then New York's streamlining exercise should have reduced such barriers and increased HIV testing rates. I used logistic regression to estimate the effects of New York's policy change. Results. New York's streamlined consent procedures led to a 31.4% (95% confidence interval [CI] = 20.9%, 41.9%) increase in the state's HIV testing rate. In absolute terms, 7% of the state's population had been tested for HIV in the preceding 6 months under the streamlined procedures, whereas only 5.3% would have been tested under the original procedures. These estimates imply that the streamlined consent procedures accounted for approximately 328 000 additional HIV tests in the 6 months after the policy change. Conclusions. Written informed consent requirements are a substantial barrier to HIV testing in the United States.There may be a trade-off between efforts to increase HIV testing rates and efforts to improve patient awareness.
Effects of time delay on the statistical fluctuations for a bistable system driven by cross-correlated noises
Authors: Zeng Chun-hua , Zhou Xiao-feng , Tao Shu-fen 
Published: April 2009

Abstract
We study the effects of time delay on the normalized correlation function C(s) and the associated relaxation time T
c for a bistable system with correlations between multiplicative and additive white noises under the condition of small time delay. Using the projection operator method, the expressions of T
c and C(s) are obtained. Based on numerical computations, it is found that the delay time τ slows down the rate of fluctuation decay of dynamical variable for the presence of positive feedback intensity (∈ > 0), while speeds up the rate of fluctuation decay of dynamical variable for the presence of negative feedback intensity (∈ < 0). The effects of the delay time τ on the T
c and C(s) are entirely opposite for ∈ 〉 0 and ∈ < 0.
Fluctuation theorems from non-equilibrium Onsager-Machlup theory for a Brownian particle in a time-dependent harmonic potential
Authors: Deza Roberto , Izús Gonzalo , Wio Horacio 
Published: April 2009

Abstract
We discuss the case of a Brownian particle which is harmonically bound and multiplicatively forced-namely bound by V(x,t)=1/2 a(t)x
2 where a(t)is externally controlled-as another instance that provides a generalization of Onsager-Machlup’s theory to non-equilibrium states, thus allowing establishment of several fluctuation theorems. In particular, we outline the derivation of a fluctuation theorem for work, through the calculation of the work probability distribution as a functional integral over stochastic trajectories.
Lagrangian relative equilibria for a gyrostat in the three-body problem
Authors: López Juan 
Published: April 2009

Abstract
In this paper we consider the noncanonical Hamiltonian dynamics of a gyrostat in the three-body problem. By means of geometric mechanics methods, we study the approximate Poisson dynamics that arise when we develop the potential of the system in Legendre series and truncate this to an arbitrary order k. After reduction of the dynamics by means of the two symmetries of the system, we consider the existence and number of equilibria which we denominate of Lagrangian type, in analogy with classic results on the topic. Necessary and sufficient conditions are established for their existence in an approximate dynamics of order k, and explicit expressions for these equilibria are given, this being useful for the subsequent study of their stability. The number of Lagrangian equilibria is thoroughly studied in approximate dynamics of orders zero and one. The main result of this work indicates that the number of Lagrangian equilibria in an approximate dynamics of order k for k ≥1 is independent of the order of truncation of the potential, if the gyrostat S
0 is almost spherical. In relation to the stability of these equilibria, necessary and sufficient conditions are given for linear stability of Lagrangian equilibria when the gyrostat is almost spherical. In this way, we generalize the classical results on equilibria of the three-body problem and many results provided by other authors using more classical techniques for the case of rigid bodies.
Photoacoustic spectroscopy for trace gas detection with cryogenic and room-temperature continuous-wave quantum cascade lasers
Authors: Zeninari Virginie , Grossel Agnès , Joly Lilian , Decarpenterie Thomas , Grouiez Bruno , Bonno Bernard , Parvitte Bertrand 
Published: April 2009

Abstract
The main characteristics that a sensor must possess for trace gas detection and pollution monitoring are high sensitivity, high selectivity and the capability to perform in situ measurements. The photacoustic Helmholtz sensor developed in Reims, used in conjunction with powerful Quantum Cascade Lasers (QCLs), fulfils all these requirements. The best cell response is # 1200 V W−1 cm and the corresponding ultimate sensitivity is j 3.3 × 10−10 W cm−11 Hz−11/2. This efficient sensor is used with mid-infrared QCLs from Alpes Lasers to reach the strong fundamental absorption bands of some atmospheric gases. A first cryogenic QCL emitting at 7.9 μm demonstrates the detection of methane in air with a detection limit of 3 ppb. A detection limit of 20 ppb of NO in air is demonstrated using another cryogenic QCL emitting in the 5.4 μm region. Real in-situ measurements can be achieved only with room-temperature QCLs. A room-temperature QCL emitting in the 7.9 μm region demonstrates the simultaneous detection of methane and nitrous oxide in air (17 and 7 ppb detection limit, respectively). All these reliable measurements allow the estimated detection limit for various atmospheric gases using quantum cascade lasers to be obtained. Each gas absorbing in the infrared may be detected at a detection limit in the ppb or low-ppb range.
Mixed spin-1/2 and spin-1 Ising model with uniaxial and biaxial single-ion anisotropy on the Bethe lattice
Authors: Ekiz Cesur , Strečka Jozef , Jaščur Michal 
Published: April 2009

Abstract
The mixed spin-1/2 and spin-1 Ising model on the Bethe lattice with both uniaxial as well as biaxial single-ion anisotropy terms is solved exactly by combining star-triangle and triangle-star mapping transformations with exact recursion relations. Magnetic properties (magnetization, phase diagrams, and compensation phenomenon) are investigated in detail. Particular attention is focused on the effect of uniaxial and biaxial single-ion anisotropies that basically influence the magnetic behavior of the spin-1 atoms.
Protective role of <i>Annona squamosa</i> linn bark extracts in DMBA induced genotoxicity
Authors: Suresh K , Manoharn S , Blessy D 
Published: April 2009

Background: Their has been no dearth of scientific literature that genotoxic agents have a causative effect in the pathogenesis of carcinomas. 7,12dimethylbenz(a)anthracene (DMBA) which is, a potent organ specific carcinogen has been found to produce mutagenic effects on cells10. Annona squamosa has a long history in traditional indian medicine for being used to treat several diseases including cancer. Objective: Aim of the present study was to investigate the protective role of Annona squamosa bark extracts in DMBA induced genotoxicity in golden Syrian hamsters. Material and methods: Genotoxicity was induced in golden Syrian hamsters by single intraperitonial injection of DMBA (30 mg/kg body weight). The antigenotoxic effect of aqueous and ethanolic bark extracts of Annona squamosa was assessed by determining the frequency of micronucleated polychromatic erythrocytes (MnPCEs) and chromosomal aberrations. Results: The frequency of MnPCEs and chromosomal aberrations in bone marrow were higher in DMBA treated animals as compared to control animals. Oral administration of aqueous and ethanolic bark extracts significantly reduced the frequency of MnPCEs and chromosomal aberration in DMBA treated hamsters. Conclusion: Although both extracts have shown antigenotoxic effect, the effect of ethanolic extract was found to be more prominent than the aqueous extract. The present study thus demonstrates the antigenotoxic effect of Annona squamosa bark extracts in DMBA induced genotoxicity in golden Syrian hamsters. Key words: Genotoxicity, DMBA, Chromosomal aberrations, MnPCEs, Annona squamosa doi: 10.3126/kumj.v6i3.1713 Kathmandu University Medical Journal (2008), Vol. 6, No. 3, Issue 23, 364-369