bluuebunny/crossref_metadata_2025 huggingface dataset:
RanBPM Contributes to Semaphorin3A Signaling through Plexin-A Receptors
Authors: Togashi Hideaki , Schmidt Eric F. , Strittmatter Stephen M.
Published: May 2006

Secreted Semaphorin3A (Sema3A) proteins are known to act as diffusible and repellant axonal guidance cues during nervous system development. A receptor complex consisting of a Neuropilin and a Plexin-A mediates their effects. Plexin-A signal transduction has remained poorly defined despite the documented involvement of collapsin response mediator protein and molecule interacting with CasL proteins (MICALs) as mediators of Plexin-A activation. Here, we defined a domain of Plexin-A1 required for Sema3A signaling in a reconstituted environment and then searched for proteins interacting with this domain. RanBPM is shown to physically interact with Plexin-A1, and the RanBPM/Plexin complex is regulated by MICAL expression. Overexpression of RanBPM cooperates with PlexinA1 to reduce non-neuronal cell spreading and strongly inhibit axonal outgrowthin vitroandin vivo. A truncated RanBPM protein blocks Sema3A responsiveness in non-neuronal and neuronal cells. Suppression of RanBPM expression reduces Sema3A responsiveness. Thus, RanBPM is a mediator of Sema3A signaling through Plexin-A. RanBPM has the potential to link Plexin-A receptors to retrograde transport and microtubule function in axonal guidance.
AnIn VitroStudy of Horizontal Connections in the Intermediate Layer of the Superior Colliculus
Authors: Lee Psyche , Hall William C.
Published: May 2006

Some models propose that the spatial and temporal distributions of premotor activity in the intermediate layer of the superior colliculus are shaped by neuronal ensembles that give rise to local excitatory and distant inhibitory connections. One function proposed for these connections is to mediate a “winner-take-all” network; the short-range excitatory connections build up the activity of neighboring cells that command orienting movements in one direction, whereas the wide-ranging inhibitory projections attenuate the activity of remote cells that command incompatible movements. We usedin vitrophotostimulation and whole-cell patch-clamp recording to test these models by measuring the spatial extent of synaptic interactions within the rat intermediate layer. Uncaging glutamate over whole-cell patch-clamped cells in the intermediate layer elicited long-lasting inward currents, resulting from direct activation of glutamate receptors expressed by the cells, and brief synaptic currents evoked by activation of presynaptic neurons. The synaptic responses comprised clusters of excitatory and inhibitory currents. The size of these responses depended on the location of the stimulus with respect to the clamped cell. Large responses were commonly evoked by stimuli within 200 μm of the soma in the intermediate layer; smaller responses could occasionally be evoked from sites as distant as 500 μm. Responses evoked by stimulation beyond this distance were rare. Although the results demonstrated powerful local excitatory and inhibitory connections, they did not support the pattern of short-range excitation and widespread inhibition predicted by the winner-take-all hypothesis.
Enhanced Excitatory Synaptic Connectivity in Layer V Pyramidal Neurons of Chronically Injured Epileptogenic Neocortex in Rats
Authors: Jin Xiaoming , Prince David A. , Huguenard John R.
Published: May 2006

Formation of new recurrent excitatory circuits after brain injuries has been hypothesized as a major factor contributing to epileptogenesis. Increases in total axonal length and the density of synaptic boutons are present in layer V pyramidal neurons of chronic partial isolations of rat neocortex, a model of posttraumatic epileptogenesis. To explore the functional consequences of these changes, we used laser-scanning photostimulation combined with whole-cell patch-clamp recording from neurons in layer V of somatosensory cortex to map changes in excitatory synaptic connectivity after injury. Coronal slices were submerged in artificial CSF (23°C) containing 100 μmcaged glutamate, APV (2-amino-5-phosphonovaleric acid), and high divalent cation concentration to block polysynaptic responses. Focal uncaging of glutamate, accomplished by switching a pulsed UV laser to give a 200–400 μs light stimulus, evoked single- or multiple-component composite EPSCs. In neurons of the partially isolated cortex, there were significant increases in the fraction of uncaging sites from which EPSCs could be evoked (“hot spots”) and a decrease in the mean amplitude of individual elements in the composite EPSC. When plotted along the cortical depth, the changes in EPSCs took place mainly between 150 and 200 μm above and below the somata, suggesting a specific enhancement of recurrent excitatory connectivity among layer V pyramidal neurons of the undercut neocortex. These changes may shift the balance within cortical circuits toward increased synaptic excitation and contribute to epileptogenesis.
A Mechanism for Vocal-Respiratory Coupling in the Mammalian Parabrachial Nucleus
Authors: Smotherman Michael , Kobayasi Kohta , Ma Jie , Zhang Shuyi , Metzner Walter
Published: May 2006

Mammalian vocalizations require the precise coordination of separate laryngeal and respiratory motor pathways. Precisely how and where in the brain vocal motor patterns interact with respiratory rhythm control is unknown. The parabrachial nucleus (PB) is known to mediate key respiratory reflexes and is also considered a principle component of the mammalian vocal motor pathway, making it a likely site for vocal-respiratory interactions, yet a specific role for the PB in vocalizing has yet to be demonstrated. To investigate the role of the PB in vocal-respiratory coordination, we pharmacologically manipulated synaptic activity in the PB while spontaneously vocalizing horseshoe bats were provoked to emit either short, single syllable or long, multisyllabic vocal motor patterns. Iontophoresis of the GABAAagonist muscimol (MUS) into the lateral PB extended expiratory durations surrounding all vocalizations and increased mean call durations. Alternatively, application of the GABAAantagonist bicuculline methiodide (BIC) shortened expirations and call durations. In addition, BIC eliminated the occurrence of multisyllabic vocalizations. BIC caused a mild increase in quiet breathing rates, whereas MUS tended to slow quiet breathing. The results indicate that GABAAreceptor-mediated inhibition in the lateral PB modulates the time course of respiratory phase switching during vocalizing, and is needed for proper coordination of calling and breathing in mammals. We hypothesize that vocal-respiratory rhythm entrainment is achieved at least in part via mechanisms similar to other forms of locomotor-respiratory coupling, namely somatosensory feedback influences on respiratory phase-switching in the lateral PB.
The Presence of Background Dopamine Signal Converts Long-Term Synaptic Depression to Potentiation in Rat Prefrontal Cortex
Authors: Matsuda Yoshiki , Marzo Aude , Otani Satoru
Published: May 2006

Executive functions of the brain are believed to require tonic dopamine inputs to the prefrontal cortex (PFC). It is unclear, however, how this background dopamine activity controls synaptic plasticity in the PFC, a possible underlying mechanism of executive functions. Using PFC slices, we show that pairing of dopamine with weak tetanic stimulation, a maneuver that otherwise induces NMDA receptor-independent long-term depression (LTD), induces long-term potentiation (LTP) when “primed” with dopamine. This “priming” occurs through the combined activation of D1and D2receptors and requires 12–40 min to develop. Moreover, concurrent synaptic activation of NMDA receptors during priming is necessary for this novel form of LTP. We suggest that a role of background dopamine signals in the PFC is to prevent high-frequency synaptic inputs from abnormally inducing LTD and to secure the induction of LTP.
Perceptual Knowledge Retrieval Activates Sensory Brain Regions
Authors: Goldberg Robert F. , Perfetti Charles A. , Schneider Walter
Published: May 2006

Although knowledge indexes our experiences of the world, the neural basis of this relationship remains to be determined. Previous neuroimaging research, especially involving knowledge biased to visual and functional information, suggests that semantic representations depend on modality-specific brain mechanisms. However, it is unclear whether sensory cortical regions, in general, support retrieval of perceptual knowledge. Using neuroimaging methods, we show that semantic decisions that index tactile, gustatory, auditory, and visual knowledge specifically activate brain regions associated with encoding these sensory experiences. Retrieval of tactile knowledge was specifically associated with increased activation in somatosensory, motor, and premotor cortical regions. In contrast, decisions involving flavor knowledge increased activation in an orbitofrontal region previously implicated in processing semantic comparisons among edible items. Perceptual knowledge retrieval that references visual and auditory experiences was associated with increased activity in distinct temporal brain regions involved in the respective sensory processing. These results indicate that retrieval of perceptual knowledge relies on brain regions used to mediate sensory experiences with the referenced objects.
Induction of Glial Fibrillary Acidic Protein Expression in Astrocytes by Nitric Oxide
Authors: Brahmachari Saurav , Fung Yiu K. , Pahan Kalipada
Published: May 2006

Increased expression of glial fibrillary acidic protein (GFAP) represents astroglial activation and gliosis during neurodegeneration. However, the molecular mechanism behind increased expression of GFAP in astrocytes is poorly understood. The present study was undertaken to explore the role of nitric oxide (NO) in the expression of GFAP. Bacterial lipopolysachharides (LPSs) induced the production of NO and the expression of GFAP in mouse primary astrocytes. Either a scavenger of NO [2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO)] or an inhibitor of inducible nitric oxide synthase [l-N6-(I-iminoethyl)-lysine hydrochloride] blocked this induction of GFAP expression. Similarly, other inducers of NO production such as interferon-γ, interleukin-1β, human immunodeficiency virus type 1 gp120, fibrillar amyloid β peptides, and double-stranded RNA (polyinosinic-polycytidilic acid) also induced the expression of GFAP through NO. The role of NO in the expression of GFAP was supported further by increased expression of GFAP byS-nitroso glutathione (GSNO), an NO donor. Interestingly, inhibition of nuclear factor κB (NF-κB) suppressed LPS- but not GSNO-induced expression of GFAP, suggesting that NO does not require NF-κB to induce GFAP and that NF-κB functions upstream of NO production. However, inhibition of LPS- and GSNO-induced expression of GFAP either by NS-2028 [a specific inhibitor of guanylate cyclase (GC)] or by KT5823 [a specific inhibitor of cGMP-activated protein kinase (PKG)], and induction of GFAP expression by either 8-Br cGMP (a cell-permeable cGMP analog) or MY-5445 (a specific inhibitor of cGMP phosphodiesterase) suggests that NO induces GFAP via GC-cGMP-PKG. This study illustrates a novel biological role of NO in regulating the expression of GFAP in astrocytes through the GC-cGMP-PKG pathway that may participate in the pathogenesis of neurodegenerative disorders.
Cultured Neural Networks: Optimization of Patterned Network Adhesiveness and Characterization of their Neural Activity
Authors: Rutten W. L. C. , Ruardij T. G. , Marani E. , Roelofsen B. H.
Published: May 2006

One type of future, improved neural interface is the “cultured probe”. It is a hybrid type of neural information transducer or prosthesis, for stimulation and/or recording of neural activity. It would consist of a microelectrode array (MEA) on a planar substrate, each electrode being covered and surrounded by a local circularly confined network (“island”) of cultured neurons. The main purpose of the local networks is that they act as biofriendly intermediates for collateral sprouts from the in vivo system, thus allowing for an effective and selective neuron–electrode interface. As a secondary purpose, one may envisage future information processing applications of these intermediary networks. In this paper, first, progress is shown on how substrates can be chemically modified to confine developing networks, cultured from dissociated rat cortex cells, to “islands” surrounding an electrode site. Additional coating of neurophobic, polyimide‐coated substrate by triblock‐copolymer coating enhances neurophilic‐neurophobic adhesion contrast. Secondly, results are given on neuronal activity in patterned, unconnected and connected, circular “island” networks. For connected islands, the larger the island diameter (50, 100 or 150 μm), the more spontaneous activity is seen. Also, activity may show a very high degree of synchronization between two islands. For unconnected islands, activity may start at 22 days in vitro (DIV), which is two weeks later than in unpatterned networks.
Limits of Nature and Advances of Technology: What Does Biomimetics Have to Offer to Aquatic Robots?
Authors: Fish F. E.
Published: May 2006

In recent years, the biomimetic approach has been utilized as a mechanism for technological advancement in the field of robotics. However, there has not been a full appreciation of the success and limitations of biomimetics. Similarities between natural and engineered systems are exhibited by convergences, which define environmental factors, which impinge upon design, and direct copying that produces innovation through integration of natural and artificial technologies. Limitations of this integration depend on the structural and mechanical differences of the two technologies and on the process by which each technology arises. The diversity of organisms that arose through evolutionary descent does not necessarily provide all possible solutions of optimal functions. However, in instances where organisms exhibit superior performance to engineered systems, features of the organism can be targeted for technology transfer. In this regard, cooperation between biologists and engineers is paramount.
Robotic Measurement and Control for Chiropractic Research
Authors: Goldsmith P. , Wynd S. , Kawchuk G.
Published: May 2006

The precision and programmability of robotic manipulators makes them suitable for biomechanics research, particularly when an experimental procedure must be accurately repeated multiple times. This paper describes a robotic system used to investigate biomechanical mechanisms of stroke in humans. A parallel robot manipulator is used to reproduce chiropractic manipulations on animal subjects using a 3‐D vision system. An algorithm for calibrating the system is proposed and tested on the robot. An iterative learning control scheme is then introduced to improve positional accuracy. Experimental results demonstrate that the calibration procedure and learning scheme are both effective.
Design, Sensing and Control of a Robotic Prosthetic Eye for Natural Eye Movement
Authors: Gu J. J. , Meng M. , Cook A. , Liu P. X.
Published: May 2006

Loss of an eye is a tragedy for a person, who may suffer psychologically and physically. This paper is concerned with the design, sensing and control of a robotic prosthetic eye that moves horizontally in synchronization with the movement of the natural eye. Two generations of robotic prosthetic eye models have been developed. The first generation model uses an external infrared sensor array mounted on the frame of a pair of eyeglasses to detect the natural eye movement and to feed the control system to drive the artificial eye to move with the natural eye. The second generation model removes the impractical usage of the eye glass frame and uses the human brain EOG (electro‐ocular‐graph) signal picked up by electrodes placed on the sides of a person′s temple to carry out the same eye movement detection and control tasks as mentioned above. Theoretical issues on sensor failure detection and recovery, and signal processing techniques used in sensor data fusion, are studied using statistical methods and artificial neural network based techniques. In addition, practical control system design and implementation using micro‐controllers are studied and implemented to carry out the natural eye movement detection and artificial robotic eye control tasks. Simulation and experimental studies are performed, and the results are included to demonstrate the effectiveness of the research project reported in this paper.
Self‐Inhibiting Modules Can Self‐Organize as a Brain of a Robot: A Conjecture
Authors: Negrete-Martínez J.
Published: May 2006

In this article we describe a new robot control architecture on the basis of self‐organization of self‐inhibiting modules. The architecture can generate a complex behaviour repertoire. The repertoire can be performance‐enhanced or increased by modular poly‐functionality and/or by addition of new modules. This architecture is illustrated in a robot consisting of a car carrying an arm with a grasping tool. In the robot, each module drives either a joint motor or a pair of wheel motors. Every module estimates the distance from a sensor placed in the tool to a beacon. If the distance is smaller than a previously measured distance, the module drives its motor in the same direction of its prior movement. If the distance is larger, the next movement will be in the opposite direction; but, if the movement produces no significant change in distance, the module self‐inhibits. A self‐organization emerges: any module can be the next to take control of the motor activity of the robot once one module self‐inhibits. A single module is active at a given time. The modules are implemented as computer procedures and their turn for participation scheduled by an endless program. The overall behaviour of the robot corresponds to a reaching attention behaviour. It is easily switched to a running‐away attention behaviour by changing the sign of the same parameter in each module. The addition of a “sensor‐gain attenuation reflex” module and of a “light‐orientation reflex” module provides an increase of the behavioural attention repertoire and performance enhancement. Since scheduling a module does not necessarily produce its sustained intervention, the architecture of the “brain” is actually providing action induction rather than action selection.
Direct measurement of fiber bridging in notched glass-ceramic-matrix composites
Authors: Dassios Konstantinos G. , Galiotis Costas
Published: May 2006

A novel, high-resolution remote Raman microscope was used for the direct in situ assessment of deformation on bridging fibers in a double-edge-notched SiC-Nicalon reinforced ceramic-glass matrix composite at various stages of monotonic tensile loading. The effect of notch length on the bridging strain profiles obtained by individually probing a large number of fibers across the bridged ligament of the composite was investigated. Bridging strain measurements in the microscale are used to identify the role and sequence of the failure micromechanisms developing within the bridging zone and are compared with their macromechanically derived counterparts. The difference of 25% in failure strain between the as-received fiber and the maximum value obtained on composite-fibers through laser Raman microscopy (LRM), is attributed to the different patterns of fiber failure in composites as compared to the techniques used for fibers characterization such as monofilament and bundle testing in air. This article demonstrates how the LRM-strain data can be utilized to obtain a direct, microscale measure of the interfacial-shear strength of the composite. The obtained interfacial shear strength (ISS) value of 7 MPa compares well with the macromechanically predicted value and offers a much higher precision compared to other experimental techniques.
Nanosphere lithography fabricated plasmonic materials and their applications
Authors: Zhang Xiaoyu , Yonzon Chanda Ranjit , Van Duyne Richard P.
Published: May 2006

Nanosphere lithography fabricated nanostructures have highly tunable localized surface plasmons, which have been used for important sensing and spectroscopy applications. In this work, the authors focus on biological applications and technologies that utilize two types of related plasmonic phenomena: localized surface plasmon resonance (LSPR) spectroscopy and surface-enhanced Raman spectroscopy (SERS). Two applications of these plasmonic materials are presented: (i) the development of an ultrasensitive nanoscale optical biosensor based on LSPR wavelength-shift spectroscopy and (ii) the SERS detection of an anthrax biomarker.
Impedance spectroscopy and nanoindentation of conducting poly(3,4-ethylenedioxythiophene) coatings on microfabricated neural prosthetic devices
Authors: Yang Junyan , Martin David C.
Published: May 2006

The electrical and mechanical properties of conducting polymer poly(3,4-ethylenedioxythiophene) coatings on microfabricated neural probes have been evaluated by electrochemical impedance spectroscopy and nanoindentation techniques. Our results reveal that for poly(3,4-ethylenedioxythiophene) coatings, the minimum impedance correlates well with the mechanical properties. The lowest impedance films are also those that are the softest. This is consistent with microstructural observations by atomic force microscopy and scanning electron microscopy showing an increase in the effective surface area (“fuzziness”) of the coatings. The presence of these conducting polymer coatings provides an intermediate step along the interface between the devices and brain tissue. This information provides clues for the design of strategies for improving the long-term performance of these electrodes in vivo.
Formation of gold-coated magnetic nanoparticles using TiO2 as a bridging material
Authors: Oliva Brittany L. , Pradhan Anindya , Caruntu Daniela , O'Connor Charles J. , Tarr Matthew A.
Published: May 2006

TiO2 nanoparticles with embedded magnetite were suspended in aqueous HAuCl4 and ultraviolet irradiated to photodeposit gold on the surface. The degree of gold coating and the wavelength of absorbance could be controlled by adjusting [HAuCl4]. Absorbance maxima were between 540-590 nm. Particles exhibited superparamagnetic properties (blocking temperature ∼170 K) whether or not coated with gold. These particles have potential applications as drug delivery agents, magnetic imaging contrast agents, and magnetically separatable photocatalysts with unique surface properties.
Characterization and control of microstructure in combinatorially prepared aluminum-silicon thin film nanocomposites
Authors: Olk C.H. , Haddad D.B.
Published: May 2006

In this paper, we describe the application of thin film combinatorial deposition methods to systematically control the microstructure of AlxSi(1−x) alloys through variations in composition and growth temperature. Discrete libraries of compositionally graded films have been sputter deposited onto silicon substrates to produce two structural phase regions: amorphous a-(Al–Si) and amorphous a-Si plus crystalline c-Al. The microstructure was investigated using x-ray diffraction while atomic force microscopy techniques were used to obtain surface morphology and phase distribution.
Intimacy and Institutionalized Cognitive Impaired Elderly
Authors: Loue Sana
Published: May 2006

About 5% of the nation’s elderly reside in nursing homes; many of these individuals experience varying levels of cognitive impairment. Although physical and nonphysical intimacy are important to their well-being, numerous structural and nonstructural barriers exist to their enjoyment of intimate relationships. Additionally, significant legal and ethical issues must be considered in the formulation of institutional policy and procedures to address the intimacy needs of cognitively impaired elderly residents. This article explores the barriers that exist and the models that have been suggested to guide institutional administrators and staff in evaluating residents’ needs, and concludes with recommendations.
Tops: The Optimum Performance Scale Approach to Improving Nursing Home Performance
Authors: Rosenfield Zachary , Branch Allan
Published: May 2006

Although nursing homes, a major and expensive institution in American life, are dedicated to caring for our elders when they need nursing care, they largely fail in that mission. Instead, nursing homes are widely feared as the place where elders go to die, neglected. Staffing is chronically short, as staff do not see nursing homes as preferred places to work. Society’s efforts to cure this situation have generally failed, in that we all paid for decades of foundation support, academic research, expert consultants, and government financial support and regulation in an effort to improve nursing homes, without getting significant results. Nursing homes taken as a whole have proven strongly resistant to even incremental improvements, let alone wholesale change, and as a result the failure persists. Most nursing homes are blind to the possibility of success. The issue and problem highlighted by these general failures of outside pressure to bring improvement, coupled with general blindness to potential success is: How can we get the nursing home industry to improve itself? The response outlined in this article is TOPS, The Optimum Performance System. TOPS works by delivering to participating managers (and their staff and board) a personal computer application (the TOPS Tool) that compares the performance of the participant to its peers, including descriptions of what all participants have done to produce their performance. The comparison is holistic, measuring all the main components of performance (quality of living, medical health, and cost) and all the sources of performance (management and operations, facilities, and community relations). The instinctual competitive needs of each manager will urge them to use this knowledge to improve their own performance.
Efficacy of an HIV Prevention Program Among Female Adolescents Experiencing Gender-Based Violence
Authors: Wingood Gina M. , DiClemente Ralph J. , Harrington Kathy F. , Lang Delia L. , Davies Susan L. , Hook Edward W. , Oh M. Kim , Hardin James W.
Published: May 2006

Objectives. We examined the efficacy of an HIV prevention intervention among African American female adolescents reporting a history of gender-based violence.

Methods. In this analysis of a subgroup of participants involved in a randomized controlled trial, consistent condom use, psychosocial mediators associated with HIV-preventive behaviors, and presence of sexually transmitted diseases were assessed at 6- and 12-month follow-ups. The intervention emphasized ethnic and gender pride, HIV knowledge, condom attitudes, healthy relationships, communication, and condom use skills.

Results. Relative to the comparison condition, participants randomized to the intervention reported using condoms more consistently, had fewer episodes of unprotected vaginal sex, engaged in a greater proportion of protected intercourse acts, were more likely to have used a condom during their most recent intercourse, were less likely to have a new sexual partner, were less likely to have a sexually transmitted disease, and demonstrated more proficient condom skills.

Conclusions. Given the substantial prevalence of gender-based violence among female adolescents and the associations observed between gender-based violence, HIV risk, and HIV infection, it is essential that HIV interventions involving young women address partner violence.
Sexual Orientation and Mental and Physical Health Status: Findings From a Dutch Population Survey
Authors: Sandfort Theo G.M. , Bakker Floor , Schellevis François G. , Vanwesenbeeck Ine
Published: May 2006

Objectives. We sought to determine whether sexual orientation is related to mental and physical health and health behaviors in the general population.

Methods. Data was derived from a health interview survey that was part of the second Dutch National Survey of General Practice, carried out in 2001 among an all-age random sample of the population. Of the 19685 persons invited to participate, 65% took part in the survey. Sexual orientation was assessed in persons aged 18 years and older and reported by 98.2% of 9684 participants. The respondents’ characteristics are comparable with those of the Dutch general population.

Results. Gay/lesbian participants reported more acute mental health symptoms than heterosexual people and their general mental health also was poorer. Gay/lesbian people more frequently reported acute physical symptoms and chronic conditions than heterosexual people. Differences in smoking, alcohol use, and drug use were less prominent.

Conclusions. We found that sexual orientation was associated with mental as well as physical health. The causal processes responsible for these differences by sexual orientation need further exploration.
Sexual and Drug Risk Behaviors Among Women Who Have Sex With Women
Authors: Bell Ann V. , Ompad Danielle , Sherman Susan G.
Published: May 2006

Objectives. We examined risk behaviors of female drug users, comparing those who reported recently having had sex with women (recent WSW), those who reported previously having had sex with women (former WSW), and those who reported never having had sex with women (never WSW).

Methods. We used data from the Risk Evaluation and Assessment of Community Health III Study. Adjusted odds for predictors of WSW status were determined via multinomial logistic regression analyses.

Results. Of the participants, 75% were never WSW, 12% were former WSW, and 13% were recent WSW. In comparison with never WSW status, significant predictors of recent WSW status were living away from one’s parents as a child (adjusted odds ratio [OR]=3.05; 95% confidence interval [CI]=1.07, 8.67) and recently having been paid for sex by men (adjusted OR=4.02; 95% CI=1.67, 9.68). Also, recently having been paid for sex by men was a significant predictor of former WSW status as opposed to never WSW status (adjusted OR=3.97; 95% CI=1.65, 9.59).

Conclusions. The recency with which they had sex with women is one of the facets influencing the risk profile of WSW. The diverse characteristics of the WSW population need to be incorporated into future studies and risk interventions targeting this group.
HIV Infection and AIDS in the Deep South
Authors: Reif Susan , Geonnotti Kristin Lowe , Whetten Kathryn
Published: May 2006

We examine epidemiological and demographic data documenting the HIV/AIDS epidemic in the Deep South region of the United States. These data document substantial increases in AIDS cases in the Deep South from 2000 to 2003. In contrast, other US regions are experiencing stable rates or small increases in new AIDS cases. Furthermore, the AIDS epidemic in the Deep South is more concentrated than in other regions among African Americans, women, and rural residents.

The Deep South also has some of the highest levels of poverty and uninsured individuals, factors that complicate the prevention and treatment of HIV infection. Further research is needed to determine the cause of the disproportionate rise in AIDS incidence and to develop effective means of preventing HIV infection and providing care of those infected in this region.
Greater Risk for HIV Infection of Black Men Who Have Sex With Men: A Critical Literature Review
Authors: Millett Gregorio A. , Peterson John L. , Wolitski Richard J. , Stall Ron
Published: May 2006

HIV rates are disproportionately higher for Black men who have sex with men (MSM) than for other MSM. We reviewed the literature to examine 12 hypotheses that might explain this disparity.

We found that high rates of HIV infection for Black MSM were partly attributable to a high prevalence of sexually transmitted diseases that facilitate HIV transmission and to undetected or late diagnosis of HIV infection; they were not attributable to a higher frequency of risky sexual behavior, nongay identity, or sexual nondisclosure, or to reported use of alcohol or illicit substances. Evidence was insufficient to evaluate the remaining hypotheses.

Future studies must address these hypotheses to provide additional explanations for the greater prevalence of HIV infection among Black MSM.
Using a Multisectoral Approach to Assess HIV/AIDS Services in the Western Region of Puerto Rico
Authors: Asencio Toro Gloria , Burns Patricia , Pimentel Daniel , Sánchez Peraza Luis Raúl , Rivera Lugo Carmen
Published: May 2006

The Enhancing Care Initiative of Puerto Rico assessed services available to people living with HIV/AIDS in the western region of Puerto Rico. Participants were 212 people living with HIV/AIDS and 116 employees from 6 agencies providing HIV/AIDS services in the region. Two main findings were that depression symptoms were present in 98.1% of people living with HIV/AIDS, and 7 of the 15 municipalities in the region did not provide any specific services to this population.

Most urgent needs identified by people living with HIV/AIDS were economic support, housing, mental and psychological services, medicines, medical treatment, and transportation. The Enhancing Care Initiative provides an example of a successful multisectoral, multidimensional volunteer team effectively overcoming challenges while translating research into interventions to enhance HIV/AIDS care.
Effects of Chlorpromazine on Aggression in Laboratory Populations of Wild House Mice
Authors: Vessey Stephen
Published: May 2006

Three confined, freely growing populations of wild house mice (Mus musculus) were studies to determine possible functions of aggressive behavior in regulating population size. Effects of a tranquilizer, chlorpromazine, on aggression and population parameters were measured. In singly caged pairs of mice chlorpromazine, mixed with the food at a rate of 0.75 mg/g food, significantly increased the number of days between litters. Also, significantly fewer young were born and weaned when compared with pairs given a control diet. Thus chlorpromazine produced no direct enhancement of reproduction. At the same dose chlorpromazine reduced fighting among C57 male mice. The growth curves of the populations prior to treatment were generally sigmoid, upper limits varying in each population. Birth and survival rates of infants declined with increasing population size. Mortality rates of adults did not vary significantly with population size. Due to a higher mortality of post—weaned males than females, sex ratios generally favored females. Aggressive rates (interactions per min) increased as the population increased, then leveled off after the after the population reaches a peak. When adjusted for population size, the rates followed the same pattern. Adult males established territories in all three cages, up to seven such males being present in a cage at one time. These males significantly heavier than non—territorial males of similar age and initiated up to 8% of the fights. Adrenal glands of territorial males were significantly lighter and thymuses significantly heavier than those of non—territorial males. Females did not defend territories but accounted for up to 50% of the fighting. Chlorpromazine (0.75 mg) was given to one population for 111 days and to a second population for 60 days after each had leveled off. Renewed population growth occurred during drug administration and aggressive rates were markedly reduced. The only effect of the drug on measured population parameters was increased infant survival. When the drug was removed from one population the numbers of mice declined and the aggressive rate increased. Reduced aggression must have produced its effect on population size through some factor(s) influencing infant survival.
An Index of Diversity and the Relation of Certain Concepts to Diversity
Authors: McIntosh Robert P.
Published: May 2006

The uses in ecology of the terms richness, diversity, homogeneity, and similarity are considered in the context of recent studies of plant and animal communities. Various uses of divesity are reviewed and an index of diversity derived from the distance measure of similarity is suggested. This index is Σi=1n2i where S equals the number of species and n equals the number of individuals in each species. This index is compared with other indices of diversity. The principal problem of measuring diversity is the assessment of the homogeneity or similarity of the sample or samples being studied. An advantage of the proposed index is that it derives from a measure of similarity of which it is a special case, and it is a special case, and it is a more natural and familiar representation of points in a coordinate system.
Vegetation of the Guadalupe Escarpment, New Mexico‐Texas
Authors: Gehlbach Frederick R.
Published: May 2006

The Guadalupe Escarpment, a Persian limestone reef, is the eastern face of a semiard—mesothermal mountain mass that rises 1,000—4,000 ft above the southwestern edge of the Great Plains. Phytocenoses range from xerophytic (Larrea, Flourensia, Acacia dominance types) on the Silty to gravelly plains, through less xerophytic (Agave, Dasylirion, Juniperus dominance types) on gravelly to bouldery lower slopes, to comparatively mesophytic (Juniperus, Quercus, Pinus dominance types) on rocky upper slopes and the escarpment peneplain. This general gradient is a vegetational continuum in which species' ecologic amplitudes are distinct but form overlapping assemblages of similar structure. Special environmental gradients are produced by topographic discontinuity. On low elevation canyon slopes, south—facing exposures support more xerophytic dominance types than north—facing exposures, although floristic differences are minimal. At highest base levels and slope elevations, south—facing exposures support the most xerophytic of all canyonside vegetation, and floristic differences between slopes are maximal. Dominance types with a tree stratum are well developed inside canyons; they form a continuous streambed—stream terrace—canyonhead sequence of increasing mesophytism. Canyon depth and water are important in supporting relict woodland dominated by Acer, Quercus, Juniperus, and Juglans. Height and coverage as stratal features plus growth contribute to a synusial description of the vegetation. Based on relative concordance of synusiae, shrub desert, succulent desert, evergreen woodland, and deciduous woodland plant formations are present. Microphyllous vs. succulent—semisucculent shrubs and half—shrubs distinguish the two desert formations. Narrow and broadleaf evergreen trees vs. broadleaf deciduous trees distinguish the two woodland formations. A mid—gradient predominance of structural diversity characterizes the ecosystem. Comparisons with other southwestern desert regions reveal that dominance types vary considerably; but the same formations recur, although in differing patterns based largely on regional edaphic differences. Formations are shifted toward the xerophytic end of an environmental gradient in the igneous—based Chisos Mountains, Texas; and succulent desert is not well developed on the north side of these mountains. Succulent desert of the Chihuahuan Desert region may not be classable with that of the Sonoran Desert region, because a tree stratum is added in the latter region. Succulent desert and evergreen woodland of the Guadalupe Escarpment could have had a common Madro—Tertiary origin based on evergreen—succulent dominance and paucity of deciduous growth forms.
A Method for Determining Water Transport in Trees
Authors: Daum C. R.
Published: May 2006

A new form of heat—flow analysis was developed to measure water transport in tree trunks. The application of the energy budget required the installation of heat—flow plates and thermocouples under the bark to measure the natural heat exchange between the water—conducting layer of xylem and the adjacent parts of the tree. The equipment was installed on two large branches of an ash tree and on the main trunk below. Over an extended period of time the sum of the flow through the two branches was equal to than through the main trunk, but early in the morning water loss was so high from the branch on the west side of the tree that water must have moved to it from the protected branch on the east. Immediately following sunrise, water loss from the east side was greater. During rain there was reversed transport, indicating that water was absorbed through the leaves. This method permits practically instantaneous measurement of transpiration losses from large trees with no disturbance of the environment of the crown.
Effects of Physical‐Chemical Factors on the Distribution and Occurrence of Some Southeastern Wyoming Phyllopods
Authors: Horne Francis
Published: May 2006

Field and laboratory evidence demonstrates that differences in tolerance to salinity and temperature of phyllopods notably affect their habitat types and seasonal occurrence. Oxygen concentration and pH are of lesser ecological consequence. The 11 phyllopods studied are categorized according to their seasonal occurrence and habitat salinities. For example, based on the tolerance of both eggs and adults, Branchinecta lindahli is eurythermal and euryhaline, whereas Triops longicaudatus is stenothermal and stenohaline. Though some adult phyllopods endure substantial ranges in salinity and temperature, their eggs are not necessarily so adapted. In some instances egg hatchability is impeded by environments not hostile to adult shrimp. Phyllopod eggs are, therefore, instrumental in defining when and where a particular species occurs. Ephemeral ponds with moderately high magnesium concentrations may be hostile to some phyllopods.
Partitioning of the Estuarine Environment by Two Species of Cancer
Authors: Jeffries H. Perry
Published: May 2006

There is a little mixing of Cancer irroratus and C. Borealis populations in Narragansett Bay, R. I. Cancer irroratus is found on sand. and C. borealis occurs in areas of course gavel and mixed rocky debris. The morphology, walking ability and serum of these crabs were examined to explain their separation in the bay. Walking ability was measured in a rotating jug. Cancer irroratus was at least five times more active and had a higher optimum temperature for walking than C. borealis. The optimum temperature for walking corresponded with distributions of both species on the east coast of North America: C. irroratus is most common in temperate waters, whereas C. borealis is a more northern, colder—water species. Cancer irroratus also had high concentrations of serum phosphate, which may be associated with its activity in nature. The concentrations of glucose, total nitrogen and chloride were the same in both species, presumably because their growth rates were similar and the salinity in both habitats was the same. Thus, C. irroratus is adapted for life on a flat, sand bottom where survival must depend upon an ability to run, catch food and escape from predators. C. borealis leads a reclusive life, hiding in crevices and relying upon its heavy claws for protection. Spatial partitioning of the bottom by Cancer is compared to temporal partitioning in the plankton by two species of Acartia. Competition within these groups might help to stabilize estuarine production.
The Effect of Soil Temperatuers on the Distribution of Neodiprion Sawfly Cocoons
Authors: Stark R. W. , Dahlsten D. L.
Published: May 2006

The distribution of cocoons of the pine—feeding sawfly, Neodiprion fulviceps (Complex), is clearly related to ground surface temperature. In full shade such as provided by a brush field, cocoons are distributed relatively uniformly in the soil around the host tree; in the open, cocoons are concentrated at the base of the tree and on the north and east sides of the bole.
Rates of Carbon Dioxide Evolution From the Forest Floor
Authors: Witkamp Martin
Published: May 2006

Evolution of CO2 from the forest floor measured by the inverted—box method was related to moisture, temperature, and age of the litter, and to CO2 evolution from oak leaves in litter bags measured by the closed—box method. Rates of CO2 evolution measured by the inverted— and closed—box methods did not differ significantly (P>0.2). Respiration rates from bagged oak leaves were significantly correlated (P<0.01) with respiration rates from the floor in an oak stand, but not with rates in pine and maple stands. In the oak stand, rates of respiration from the forest floor and from litter bags were highly significantly correlated (P<0.01) with temperature, litter age, and moisture in decreasing order of influence. The influence of litter age was much higher in litter bags than in the forest floor. The variability of temperature and moisture in the forest floor was lower than in litter bags. Rates of respiration from the floors of pine, oak, and maple stands were not significantly different (P>0.05).
The Temperature and Humidity Relations of Some Bog Pselaphid Beetles
Authors: Reichle David E.
Published: May 2006

Of the many microclimatic variables, temperature and moisture exert a considerable influence upon the numbers and kinds of arthropods found in particular habitats. Experimental temperature and humidity gradients permitted determinations of the responses of five bog—inhabiting species of pselaphid beetles to these factors. Significant differences were found between species with respect to their temperature preferenda and preferred temperature ranges: Bythinopsis tychoides, 21.5 ° 0.81, 25.9 — 15.3°C; Decarthron defectum, 28.5 ° 0.55, 31.4 — 24.0; Pselaphus ulkei, 19.5 ° 0.86, 24.7 — 13.0; Reichenbachia borealis, 21.+ ° 0.99, 26.2 — 14.4; Rybaxis clavata, 28.3 ° 0.41, 29.9 — 25.1. Species reactions were correlated with the natural environmental conditions of their microhabitats and predilection of index" species for unique microhabitats within the bog sere. The consistent response of all species toward saturated humidities (95—100% relative humidity) was paralleled by the near—saturated humidities of the interstices of moss microhabitats. Temperature stratification within moss microhabitats and differential species responses to temperature are postulated as mechanisms restricting certain species to different seral stages and isolating sympatric species in similar habitats.
Effect of Light Intensity on the Drift of Stream Invertebrates
Authors: Holt Charles S. , Waters Thomas F.
Published: May 2006

Various experiments were conducted in a small Minnesota stream to determine the effect of light intensity on the circadian rhythms in drift of two aquatic invertebrates, the nymph of the mayfly Baetis vagans McDunnough and the amphipod Gammarus pseudolimnaeus Bousfield. Experiments included 1) artifical light in an exclosure which insured that experimental conditions were applied only to the organisms on the stream bottom area in the exclosure, 2) artificial light in the open stream, and 3) artificially produced darkness in an exclosure. A threshold of light intensity which, decreasing, initiated high drift rates and which, increasing, caused cessation of drift, was about 0.1 ft—c (1 lux) for both species. Continuous artificial light above the threshold level for an entire night period, and also for 4 consecutive days, depressed the normal high nocturnal drift rates in the exclosure to near daytime levels; on the fifth night in the exclosure, in darkness, drift was much higher than normal. Continuous artifical light for an entire night period on an open stream riffle also greatly depressed noctural drift. In another open stream experiment, in which organisms drifted from darkness onto a lighted riffle, some settled to the bottom as evidenced by depressed nocturnal drift rates, while other drifted through the light and off the riffle. The effect of shortened and lengthened “night” periods, produced by artificial light and darkness respectively, was to shift the circadian pattersn of drift correspondingly. Rapidly alternating periods (15 min) of light and darkness in the exclosure produced correspondingly alternating drift, with drift rates high in darkness and low in light. When the normal day—night cycle of light was reversed with artificial light and darkness, the phases of the circadian rhythm in drift were also reversed. Observed circadian rhythms in drift appear exogenously controlled; if an endogenous rhythm exists at all, it is very weak and is influenced strongly by environmental light conditions.