bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Alumina Fiber Content on Properties of Non-Asbestos Organic Brake Friction Material
Authors: Talegaonkar Rahul P. , Gopinath K.
Published: June 2008

In order to replace the conventional asbestos friction material, a non-asbestos organic (NAO) friction material is developed with alumina fiber. The effect of alumina fiber content from 0—20 wt% on the physical and mechanical properties is investigated. Making use of these properties, the wear properties are predicted. It is observed that with the increase in alumina content the specific gravity and the elastic modulus of the material decreases. But the compressive strength, hardness, tensile strength, and shear strength increases linearly. There was no significant change in glass transition and decomposition temperature of the composites with variation in alumina fiber content. The theoretical prediction based on simplified assumptions indicates that wear properties are improving with alumina content.
Convergent Validity of the Early Childhood Behavior Problem Screening Scale
Authors: Griffith Annette K. , Nelson J. Ron , Epstein Michael H. , Pederson Bjorn
Published: June 2008

This study examined the convergent validity of the parent and teacher versions of the Early Childhood Behavior Problem Screening Scale (ECBPSS) with the Child Behavior Checklist (CBCL) and the Caregiver-Teacher Report Form (C-TRF), respectively. Data were collected on a sample of preschool and kindergarten students ( n = 149) from two medium-sized cities in the Midwest. Analyses of both the parent and teacher versions of the ECBPSS were correlated with the corresponding Internalizing, Externalizing, and Total Problem scale scores of the CBCL and the C-TRF. The present findings and future research directions and limitations are discussed.
Sound and the Everyday in Qualitative Research
Authors: Hall Tom , Lashua Brett , Coffey Amanda
Published: June 2008

In this article, a constitutive aspect of the everyday world is attended to, which is too often absent or suppressed in social scientific accounts of social life: noise. A question is raised as to how social science has addressed the question of noise, through a reconsideration of sound and the everyday. Conventional “good practice” for the organization and conduct of research interviews is compared with alternative approaches more open to the space of everyday sounds, and the practice of soundwalking—the mobile exploration of (local) space and sounds—is offered as a productive context for the creative disturbance of the conventional interview. In closing, some of the possibilities of noise as these have been brought home to us in our own research with young people in noisy, everyday settings are set out.
Secular Blasphemy
Authors: Haywood Rolling James
Published: June 2008

Unnaming the axiomatic constructs of a named identity—that which is thought to be fitting within a given regime of definition—becomes then an act of secular blasphemy, a performance of decanonizing translation that discursively relocates and reinscribes communicated meaning from power, prefix, and prefigurement to perpetual movement. Departing from Homi Bhabha's description of blasphemy as a transgressive act, this article blasphemes the certainty of definition in research writing, illuminating the performance of blasphemy as a source of new social names and the migration of norms and meaning. This article is the third in a trilogy of research forays exploring the intersection of autoethnography, critical race theory, and performance studies. This new research, written to follow up Rolling (2004a, 2004b), is a continuation of the author's effort to establish the efficacy of a poststructural and poetic aesthetic in qualitative research writing.
Marco Said I Look Like Charcoal
Authors: Velázquez Vargas Yarma
Published: June 2008

When race is so self-evident that it becomes “unspoken,” it becomes a text that can be arbitrarily read or not read at all. When race is thought of as shades or textures of color that paint the already loaded canvas of our ethnicities, it is the reader who has the power of interpretation, opening the possibility for multiple readings that will shape identity. With this article, the author makes an attempt to understand the issues of race and ethnicity in Puerto Rico, using her life as an example.
No Longer Loss: Autoethnographic Stammering
Authors: Wyatt Jonathan
Published: June 2008

This article explores the (continuing) experience of loss, asking how we come to know loss as the losing event itself becomes more distant and the lost begins to fade in the memory. Following an earlier article about the death of his father 3 years ago, the author tells further stories about his father and draws from encounters in his counseling practice. He works with the Deleuzian concept of stammering , as he attempts to find words that take lines of flight and that do justice to the aporetic.
The State of Unions
Authors: Tillmann Lisa M.
Published: June 2008

At the 2005 Qualitative Inquiry conference, the author delivered a poem and slide show, “The State of Unions: Activism (and In-Activism) in Decision 2004.” The performance processed the election in the context of her research community, a network of gay male friends—marginalized by sexual orientation but privileged by sex, gender expression, race, class, and education. Audience members offered mixed responses, some praising its provocative content, others criticizing the author's position and tone, which some perceived as hostile, even as “gay bashing.”
A Lifestyle Approach for Primary Cardiovascular Disease Prevention in Perimenopausal to Early Postmenopausal Women
Authors: Pettee Kelley K. , Storti Kristi L. , Conroy Molly B. , Ainsworth Barbara E.
Published: June 2008

Cardiovascular disease (CVD) is the leading cause of death among women in the United States. A large proportion of deaths attributable to CVD occur in asymptomatic women, making early detection and diagnosis difficult. As a result, women tend to be diagnosed at later stages of disease when compared with men. In addition, women have not experienced as great a decline in CVD mortality in recent decades as have men. Therefore, the development of primary CVD prevention strategies to decrease the CVD risk in women has become a major public health priority and creates the need for alternate strategies to be developed to decrease CVD risk in women. The success of a nonpharmacological, lifestyle approach for primary CVD prevention has recently been demonstrated in perimenopausal to early postmenopausal women. Two clinical trials, the Women's Healthy Lifestyle Project (WHLP) and Women On the Move through Activity and Nutrition (WOMAN) study, examined the role of lifestyle to prevent unfavorable CVD risk factor changes that typically occur as a woman transitions through menopause. In both studies, a lifestyle intervention approach, with modest dietary restrictions and increased leisure physical activity, was effective for weight loss and/or weight maintenance and CVD risk factor reduction. More research is needed to determine the long-term benefits of a lifestyle intervention to prevent CVD in women. The existing evidence suggests that the promotion of healthy lifestyle practices by health care providers is a valuable strategy for CVD risk factor reduction in women transitioning through menopause.
The Effect of Exercise During Pregnancy on Maternal Outcomes: Practical Implications for Practice
Authors: Lewis Beth , Avery Melissa , Jennings Ernestine , Sherwood Nancy , Martinson Brian , Crain A. Lauren
Published: June 2008

The American College of Obstetricians and Gynecologists recommends that women with low-risk pregnancies participate in moderate-intensity exercise during their pregnancy. Currently, only 15.1% of pregnant women exercise at the recommended levels, which is significantly lower than the general population's 45%. One potential reason is that exercise during pregnancy is perceived as risky. In this article, the authors provide a critical review of the literature examining the effect of exercise on preeclampsia, gestational diabetes, weight gain, labor and birth, and other issues associated with pregnancy. Overall, the evidence indicates that exercise during pregnancy is safe and perhaps even reduces the risk of preeclampsia and gestational diabetes. The evidence for weight gain and labor and birth (rates of cesarean sections, duration of labor) is mixed. Unfortunately, much of the research examining exercise during pregnancy is observational, and the few randomized controlled trials that do exist are small and inadequately powered. Taken together, given the potential benefits of exercise during pregnancy and the lack of evidence for harmful effects on the mother and newborn, practitioners should encourage their healthy pregnant patients to exercise. Practical guidelines for recommending exercise to pregnant women are presented.
A phosphatidylserine binding site in factor Va C1 domain regulates both assembly and activity of the prothrombinase complex
Authors: Majumder Rinku , Quinn-Allen Mary Ann , Kane William H. , Lentz Barry R.
Published: June 2008

Tightly associated factor Va (FVa) and factor Xa (FXa) serve as the essential prothrombin-activating complex that assembles on phosphatidylserine (PS)–containing platelet membranes during blood coagulation. We have previously shown that (1) a soluble form of PS (C6PS) triggers assembly of a fully active FVa-FXa complex in solution and (2) that 2 molecules of C6PS bind to FVa light chain with one occupying a site in the C2 domain. We expressed human factor Va (rFVa) with mutations in either the C1 domain (Y1956,L1957)A, the C2 domain (W2063,W2064)A, or both C domains (Y1956,L1957,W2063,W2064)A. Mutations in the C1 and C1-C2 domains of rFVa reduced the rate of activation of prothrombin to thrombin by FXa in the presence of 400 μM C6PS by 14 000- to 15 000-fold relative to either wild-type or C2 mutant factor rFVa. The Kd's of FXa binding with rFVa (wild-type, C2 mutant, C1 mutant, and C1-C2 mutant) were 3, 4, 564, and 624 nM, respectively. Equilibrium dialysis experiments detected binding of 4, 3, and 2 molecules of C6PS to wild-type rFVa, C1-mutated, and C1,C2-mutated rFVa, respectively. Because FVa heavy chain binds 2 molecules of C6PS, we conclude that both C2 and C1 domains bind one C6PS, with binding to the C1 domain regulating prothrombinase complex assembly.
Unrelated donor umbilical cord blood transplantation for inherited metabolic disorders in 159 pediatric patients from a single center: influence of cellular composition of the graft on transplantation outcomes
Authors: Prasad Vinod K. , Mendizabal Adam , Parikh Suhag H. , Szabolcs Paul , Driscoll Timothy A. , Page Kristin , Lakshminarayanan Sonali , Allison June , Wood Susan , Semmel Deborah , Escolar Maria L. , Martin Paul L. , Carter Shelly , Kurtzberg Joanne
Published: June 2008

Outcomes of 159 young patients with inherited metabolic disorders (IMDs) undergoing transplantation with partially HLA-mismatched unrelated donor umbilical cord blood were studied to investigate the impact of graft and patient characteristics on engraftment, overall survival (OS), and graft-versus-host disease (GVHD). Patients received myeloablative chemotherapy (busulfan, cyclophosphamide, ATG) and cyclosporine-based GVHD prophylaxis. Infused cell doses were high (7.57 × 107/kg) because of the patients' young age (median, 1.5 years) and small size (median, 12 kg). Median follow-up was 4.2 years (range, 1-11 years). The cumulative incidences of neutrophil and platelet engraftment were 87.1% (95% confidence interval [CI], 81.8%-92.4%) and 71.0% (95% CI, 63.7%-78.3%). A total of 97% achieved high (> 90%) donor chimerism. Serum enzyme normalized in 97% of patients with diseases for which testings exist. Grade III/IV acute GVHD occurred in 10.3% (95% CI, 5.4%-15.2%) of patients. Extensive chronic GVHD occurred in 10.8% (95% CI, 5.7%-15.9%) of patients by 1 year. OS at 1 and 5 years was 71.8% (95% CI, 64.7%-78.9%) and 58.2% (95% CI, 49.7%-66.6%) in all patients and 84.5% (95% CI, 77.0%-92.0%) and 75.7% (95% CI, 66.1%-85.3%) in patients with high (80-100) performance score. In multivariate analysis, favorable factors for OS were high pretransplantation performance status, matched donor/recipient ethnicity, and higher infused colony forming units.
Interfering RNA-mediated purine analog resistance for in vitro and in vivo cell selection
Authors: Porter Christopher C. , DeGregori James
Published: June 2008

The advancement of gene therapy has been slowed, in part, by inefficient transduction of targeted cells and poor long-term engraftment of genetically modified cells. Thus, the ability to select for a desired population of cells within a recipient would be of great benefit for improving gene therapy. Proposed strategies for in vivo cell selection using drug resistance genes have had disappointing outcomes and/or require highly genotoxic medications to be effective. We hypothesized that resistance to purine analogs, a well-tolerated, relatively low-toxicity class of medications, could be provided to cells using interfering RNA against hypoxanthine phosphoribosyl transferase. Using a lentiviral vector, we found that interfering RNA-mediated purine analog resistance (iPAR) provided relative resistance to 6-thioguanine (6TG) in murine hematopoietic cells compared with control- and untransduced cells. iPAR attenuated 6TG-induced G2/M checkpoint activation, cell-cycle arrest, and apoptosis. Furthermore, in recipients of transplanted bone marrow cells with iPAR, treatment with 6TG resulted in increased percentages of transduced peripheral blood cells and hematopoietic progenitor cells in the bone marrow. Secondary transplantations resulted in higher hematopoietic contributions from 6TG-treated primary recipients relative to phosphate-buffered saline-treated recipients. These findings indicate that iPAR/6TG can be used for in vivo hematopoietic progenitor cell selection.
Thrombocytosis and leukocytosis interaction in vascular complications of essential thrombocythemia
Authors: Carobbio Alessandra , Finazzi Guido , Antonioli Elisabetta , Guglielmelli Paola , Vannucchi Alessandro M. , Delaini Federica , Guerini Vittoria , Ruggeri Marco , Rodeghiero Francesco , Rambaldi Alessandro , Barbui Tiziano
Published: June 2008

To elucidate the role of thrombocytosis, alone or in combination with standard (age, previous cardiovascular events) and novel (leukocytosis, JAK2V617F mutational status) risk factors, in the cardiovascular events of essential thrombocythemia (ET), we analyzed a cohort of 1063 patients. We found that a platelet count at diagnosis greater than 1000 × 109/L was associated with significantly lower rate of thrombosis in multivariable analysis and, if combined with leukocytes less than 11 × 109/L, pointed to a “low-risk” category with a rate of thrombosis of 1.59% of patients/year. On the contrary, the highest risk category (thrombosis rate, 2.95% of patients/year) was constituted of patients with leukocytosis, lower platelet count, and a JAK2V617F mutated genotype in most cases (77% vs 26% in the low-risk group), independently from standard risk factors. These data challenge the theory that elevated platelet count increases thrombosis risk in ET and suggest prospective clinical trials to support this hypothesis.
Re-searcher: a system for recurrent detection of homologous protein sequences
Authors: Repšys Valdemaras , Margelevičius Mindaugas , Venclovas Česlovas
Published: June 2008

Background

Sequence searches are routinely employed to detect and annotate related proteins. However, a rapid growth of databases necessitates a frequent repetition of sequence searches and subsequent analysis of obtained results. Although there are several automatic systems available for executing periodical sequence searches and reporting results, they all suffer either from a lack of sensitivity, restrictive database choice or limited flexibility in setting up search strategies. Here, a new sequence search and reporting software package designed to address these shortcomings is described.

Results

Re-searcher is an open-source highly configurable system for recurrent detection and reporting of new homologs for the sequence of interest in specified protein sequence databases. Searches are performed using PSI-BLAST at desired time intervals either within NCBI or local databases. In addition to searches against individual databases, the system can perform "PDB-BLAST"-like combined searches, when PSI-BLAST profile generated during search against the first database is used to search the second database. The system supports multiple users enabling each to separately keep track of multiple queries and query-specific results.

Conclusions

Re-searcher features a large number of options enabling automatic periodic detection of both close and distant homologs. At the same time it has a simple and intuitive interface, making the analysis of results even for a large number of queries a straightforward task.
Effects of social approval bias on self-reported fruit and vegetable consumption: a randomized controlled trial
Authors: Miller Tracy M , Abdel-Maksoud Madiha F , Crane Lori A , Marcus Al C , Byers Tim E
Published: June 2008

Background

Self-reports of dietary intake in the context of nutrition intervention research can be biased by the tendency of respondents to answer consistent with expected norms (social approval bias). The objective of this study was to assess the potential influence of social approval bias on self-reports of fruit and vegetable intake obtained using both food frequency questionnaire (FFQ) and 24-hour recall methods.

Methods

A randomized blinded trial compared reported fruit and vegetable intake among subjects exposed to a potentially biasing prompt to that from control subjects. Subjects included 163 women residing in Colorado between 35 and 65 years of age who were randomly selected and recruited by telephone to complete what they were told would be a future telephone survey about health. Randomly half of the subjects then received a letter prior to the interview describing this as a study of fruit and vegetable intake. The letter included a brief statement of the benefits of fruits and vegetables, a 5-A-Day sticker, and a 5-a-Day refrigerator magnet. The remainder received the same letter, but describing the study purpose only as a more general nutrition survey, with neither the fruit and vegetable message nor the 5-A-Day materials. Subjects were then interviewed on the telephone within 10 days following the letters using an eight-item FFQ and a limited 24-hour recall to estimate fruit and vegetable intake. All interviewers were blinded to the treatment condition.

Results

By the FFQ method, subjects who viewed the potentially biasing prompts reported consuming more fruits and vegetables than did control subjects (5.2 vs. 3.7 servings per day, p < 0.001). By the 24-hour recall method, 61% of the intervention group but only 32% of the control reported eating fruits and vegetables on 3 or more occasions the prior day (p = 0.002). These associations were independent of age, race/ethnicity, education level, self-perceived health status, and time since last medical check-up.

Conclusion

Self-reports of fruit and vegetable intake using either a food frequency questionnaire or a limited 24-hour recall are both susceptible to substantial social approval bias. Valid assessments of intervention effects in nutritional intervention trials may require objective measures of dietary change.
Chemical markers for the quality control of herbal medicines: an overview
Authors: Li Songlin , Han Quanbin , Qiao Chunfeng , Song Jingzheng , Lung Cheng Chuen , Xu Hongxi
Published: June 2008

Selection of chemical markers is crucial for the quality control of herbal medicines, including authentication of genuine species, harvesting the best quality raw materials, evaluation of post-harvesting handling, assessment of intermediates and finished products, and detection of harmful or toxic ingredients. Ideal chemical markers should be the therapeutic components of herbal medicines. However, for most herbal medicines, the therapeutic components have not been fully elucidated or easily monitored. Bioactive, characteristic, main, synergistic, correlative, toxic and general components may be selected. This article reviews the effective use of chemical markers in the quality control of herbal medicines including the selection criteria considering the roles and physicochemical factors which may affect the effective use of chemical markers.
Epigenetic mechanisms of age-dependent KIR2DL4 expression in T cells
Authors: Li Guangjin , Weyand Cornelia M , Goronzy Jörg J
Published: June 2008

Killer Ig-like receptor (KIR) expression is mostly restricted to NK cells controlling their activation. With increasing age, KIRs are expressed on T cells and contribute to age-related diseases. We examined epigenetic mechanisms that determine the competency of T cells to transcribe KIR2DL4. Compared with Jurkat cells and CD4+CD28+ T cells from young individuals, DNA methyltransferase (DNMT) inhibition was strikingly more effective in T cells from elderly adults and the CD4+CD28− T cell line HUT78 to induce KIR2DL4 transcription. In these susceptible cells, the KIR2DL4 promoter was partially demethylated, and dimethylated H3-Lys 4 was increased, and all other histone modifications were characteristic for an inactive promoter. In comparison, NK cells had a fully demethylated KIR2DL4 promoter and the full spectrum of histone modifications indicative of active transcription with H3 and H4 acetylation, di- and trimethylated H3-Lys 4, and reduced, dimethylated H3-Lys 9. These results suggest that an increased competency of T cells to express KIR2DL4 with aging is conferred by a selective increase in H3-Lys 4 dimethylation and limited DNA demethylation. The partially accessible promoter is sensitive to DNMT inhibition, which is sufficient to induce full transcription without further histone acetylation and methylation.
The iron export protein ferroportin 1 is differentially expressed in mouse macrophage populations and is present in the mycobacterial-containing phagosome
Authors: Van Zandt Kristopher E , Sow Fatoumata B , Florence William C , Zwilling Bruce S , Satoskar Abhay R , Schlesinger Larry S , Lafuse William P
Published: June 2008

Intracellular pathogens, including Mycobacterium tuberculosis, obtain iron from the host for their survival. Ferroportin 1 (FPN1; SLC40A1) is the sole iron exporter from mammalian cells and is expressed in the duodenum and macrophages. In the present study, we show that FPN1 mRNA levels in the mouse macrophage cell line RAW264.7 are synergistically induced by treatment with live or γ-irradiated M. tuberculosis and IFN-γ. FPN1 mRNA levels were also induced by Mycobacterium avium and IFN-γ in RAW264.7 cells and the mouse alveolar macrophage cell line AMJ2-C8. Treatment of mouse resident peritoneal macrophages with M. tuberculosis and IFN-γ resulted in a sixfold increase in FPN1 mRNA expression. In contrast, M. tuberculosis and IFN-γ inhibited FPN1 mRNA expression in bone marrow-derived macrophages and lung macrophages, which have high basal levels of FPN1 mRNA expression. Using confocal microscopy, FPN1 protein localized rapidly to M. tuberculosis phagosomes after infection in RAW264.7 macrophages. In RAW264.7 cells expressing wild-type natural resistance-associated macrophage protein 1 (Nramp1Gly169), FPN1 and Nramp1 partially colocalized in late endosomes/lysosomes prior to infection. After 2 h of infection, Nramp1 and FPN1 were present in M. tuberculosis phagosomes. Our studies provide evidence for transcriptional regulation of FPN1 by pathogenic mycobacteria and IFN-γ, which is dependent on the macrophage type. The trafficking of FPN1 to the M. tuberculosis phagosome suggests that it is involved in regulating iron availability to the mycobacteria in this locale.
Vocal identity and species recognition in male Australian sea lions,Neophoca cinerea
Authors: Gwilliam Jessica , Charrier Isabelle , Harcourt Robert G.
Published: June 2008

The acoustic channel is important for communication in otariids (fur seals and sea lions). Discrimination between species, sex or individuals is essential in communication; therefore insight into the role of vocalisations in recognition is vital to understanding otariid social interactions. We measured vocalisations and their use in discriminating sex and species in male Australian sea lions (Neophoca cinerea). Barking calls of mature males were recorded and analysed based on five acoustic parameters. A discriminant function analysis classified calls to the correct individual at a classification rate of 56%, suggesting that male barking calls are individually distinctive with the potential to facilitate individual vocal recognition. Playback experiments were used to assess the role of vocalisations in sex and species recognition both in and out of the breeding season. Males showed significantly stronger reactions to both conspecific and heterospecific males than they did to conspecific females and were most responsive during the breeding season. Australian sea lion males have the most depauperate vocal repertoire of any otariid. This simple repertoire may reflect the ecological circumstances in which these animals breed, with very low colony densities, asynchronous breeding and low levels of polygyny. Yet even in this simple system, males are able to discriminate between males and females of their own species, and distinguish the calls of conspecifics from other species. The barking calls of male Australian sea lions have sufficient information embedded to provide the potential for individual discrimination and this ability will be assessed in future studies.
Diapause in tardigrades: a study of factors involved in encystment
Authors: Guidetti Roberto , Boschini Deborah , Altiero Tiziana , Bertolani Roberto , Rebecchi Lorena
Published: June 2008

Stressful environmental conditions limit survival, growth and reproduction,or these conditions induce resting stages indicated as dormancy. Tardigrades represent one of the few animal phyla able to perform both forms of dormancy:quiescence and diapause. Different forms of cryptobiosis (quiescence) are widespread and well studied, while little attention has been devoted to the adaptive meaning of encystment (diapause). Our goal was to determine the environmental factors and token stimuli involved in the encystment process of tardigrades. The eutardigrade Amphibolus volubilis, a species able to produce two types of cyst (type 1 and type 2), was considered. Laboratory experiments and long-term studies on cyst dynamics of a natural population were conducted. Laboratory experiments demonstrated that active tardigrades collected in April produced mainly type 2 cysts, whereas animals collected in November produced mainly type 1 cysts, indicating that the different responses are functions of the physiological state at the time they were collected. The dynamics of the two types of cyst show opposite seasonal trends: type 2 cysts are present only during the warm season and type 1 cysts are present during the cold season. Temperature represents the environmental factor involved in induction, maintenance and termination of the cyst. We also obtained evidence that A. volubilis is able to perform both diapause and cryptobiosis,even overlapping the two phenomena. The induction phase of tardigrade encystment can be compared to the induction phase of insect diapause, also indicating an involvement of endogenous factors in tardigrade encystment. As in insect diapause, tardigrade encystment can be considered a diapausing state controlled by exogenous and endogenous stimuli.
Phylogeny, scaling, and the generation of extreme forces in trap-jaw ants
Authors: Spagna Joseph C. , Vakis Antonis I. , Schmidt Chris A. , Patek Sheila N. , Zhang Xudong , Tsutsui Neil D. , Suarez Andrew V.
Published: June 2008

Trap-jaw ants of the genus Odontomachus produce remarkably fast predatory strikes. The closing mandibles of Odontomachus bauri, for example, can reach speeds of over 60 m s–1. They use these jaw strikes for both prey capture and locomotion – by striking hard surfaces, they can launch themselves into the air. We tested the hypothesis that morphological variation across the genus is correlated with differences in jaw speeds and accelerations. We video-recorded jaw-strikes at 70 000–100 000 frames s–1 to measure these parameters and to model force production. Differences in mean speeds ranged from 35.9±7.7 m s–1 for O. chelifer, to 48.8±8.9 m s–1 for O. clarus desertorum. Differences in species' accelerations and jaw sizes resulted in maximum strike forces in the largest ants (O. chelifer) that were four times those generated by the smallest ants (O. ruginodis). To evaluate phylogenetic effects and make statistically valid comparisons, we developed a phylogeny of all sampled Odontomachus species and seven outgroup species (19 species total) using four genetic loci. Jaw acceleration and jaw-scaling factors showed significant phylogenetic non-independence, whereas jaw speed and force did not. Independent contrast (IC) values were used to calculate scaling relationships for jaw length, jaw mass and body mass, which did not deviate significantly from isometry. IC regression of angular acceleration and body size show an inverse relationship, but combined with the isometric increase in jaw length and mass results in greater maximum strike forces for the largest Odontomachus species. Relatively small differences (3%) between IC and species-mean based models suggest that any deviation from isometry in species' force production may be the result of recent selective evolution, rather than deep phylogenetic signal.
Light and peptidergic eclosion hormone neurons stimulate a rapid eclosion response that masks circadian emergence inDrosophila
Authors: McNabb Susan L. , Truman James W.
Published: June 2008

Light signals can entrain circadian clocks, but they can also mask aspects of the circadian output. We have analyzed the masking effects of a lights-on(LOn) signal on Drosophila eclosion. The LOn response results in 12–21% of the flies that emerge on a given day eclosing within 10 min of the LOn signal. Flies that lack the neuropeptide eclosion hormone (EH), or in which its release is inhibited by the tetanus toxin light chain, lack the response. Optic photoreceptors in both the ocelli and the compound eyes appear to be required for the response. The LOn signal has two effects: (1) it drastically reduces the interval between EH release and eclosion, presumably by suppressing a transient descending inhibition that immediately follows EH release, and (2) it stimulates premature EH release. The LOn signal does not influence the latency of wing spreading, an EH-regulated post-ecdysis behavior.
Effects of altering flow and odor information on plume tracking behavior in walking cockroaches, Periplaneta americana (L.)
Authors: Willis Mark A. , Avondet Jennifer L. , Finnell Andrew S.
Published: June 2008

Animals using odor plumes to locate resources are activated to track these plumes by the presence of an attractive odor, and typically steer toward the source using directional cues from the flowing air or water bearing the odor. We challenged freely walking virgin male cockroaches, Periplaneta americana, to track plumes of airborne female pheromone and then video-recorded and analyzed their responses as the odor plume and wind were independently manipulated. Plume tracking males that experienced the total loss of directional air flow halfway to the odor source showed little change in their performance, and 100% were able to quickly locate the pheromone source. By contrast, males experiencing a sudden loss of odor while tracking a plume rapidly changed their behavior; often turning downwind and retracing their steps to the release point, or walking in loops, but rarely moving upwind to the previous location of the source. In a subsequent experiment, in order to determine whether a memory of the previously experienced wind direction could provide the directional information necessary to locate an odor source, we challenged males to track plumes in zero wind after pre-exposing them to: (1) wind and pheromone, (2) wind only, and (3) neither wind nor pheromone. These were compared to males tracking a wind-borne pheromone plume, in which case, all males were able to locate the pheromone source. Our results show that males require the detection of wind and pheromone simultaneously during plume tracking in order to quickly and efficiently locate the odor source. These results are consistent with those reported from flying moths tracking wind-borne pheromone plumes, and suggest that the control system underlying this behavior requires ongoing simultaneous experience with wind and odor information during the performance of the behavior to operate efficiently.
Integration within and between muscles during terrestrial locomotion:effects of incline and speed
Authors: Higham Timothy E. , Biewener Andrew A.
Published: June 2008

Animals must continually adapt to varying locomotor demands when moving in their natural habitat. Despite the dynamic nature of locomotion, little is known about how multiple muscles, and different parts of a muscle, are functionally integrated as demand changes. In order to determine the extent to which synergist muscles are functionally heterogeneous, and whether this heterogeneity is altered with changes in demand, we examined the in vivo function of the lateral (LG) and medial (MG) gastrocnemius muscles of helmeted guinea fowl (Numida meleagris) during locomotion on different inclines (level and uphill at 14°) and at different speeds (0.5 and 2.0 m s–1). We also quantified function in the proximal(pMG) and distal (dMG) regions of the MG to examine the extent to which a single muscle is heterogeneous. We used electromyography, sonomicrometry and tendon force buckles to quantify activation, length change and force patterns of both muscles, respectively. We show that the LG and MG exhibited an increase in force and stress with a change in gait and an increase in locomotor speed, but not with changes in incline. While the LG and MG exhibited similar levels of stress when walking at 0.5 m s–1,stress in the LG was 1.8 times greater than in the MG when running at 2.0 m s–1. Fascicle shortening increased with an increase in speed on both inclines for the LG, but only on the level for the pMG. Positive work performed by the LG exceeded that of the pMG and dMG for all conditions, and this difference was magnified when locomotor speed increased. Within the MG,the pMG shortened more, and at a faster rate than the dMG, resulting in a greater amount of positive work performed by the pMG. Mean spike amplitude of the electromyogram (EMG) bursts increased for all muscle locations with an increase in speed, but changes with incline were more variable. The functional differences between the LG and MG are likely due to the different moments each exerts at the knee, as well as differences in motor unit recruitment. The differences within the MG are likely due to motor unit recruitment differences, but also differences in architecture. Fascicles within the dMG insert into an extensive aponeurosis, which results in a higher apparent dynamic stiffness relative to fascicles operating within the pMG. On the level surface, the greater compliance of the pMG leads to increased stretch of its fascicles at the onset of force, further enhancing force production. Our results demonstrate the capacity for functional diversity between and within muscle synergists, which occur with changes in gait, speed and grade.
The contribution of axial fiber extensibility to the adhesion of viscous capture threads spun by orb-weaving spiders
Authors: Opell Brent D. , Markley Brian J. , Hannum Charles D. , Hendricks Mary L.
Published: June 2008

The viscous capture threads produced by over 4000 species of orb-weaving spiders are formed of regularly spaced aqueous droplets supported by a pair of axial fibers. These threads register increased stickiness when spans of increasing lengths contact a surface, indicating that adhesion is recruited from multiple droplets. This study examined threads produced by five species to test the hypothesis that axial fiber extensibility is crucial for this summation of adhesion. It did so by comparing the stickiness of unstretched threads with threads that had been elongated to reduce the extensibility of their axial fibers. As stretching these threads also increased the distance between their droplets, we measured the stickiness of stretched threads with contact plates whose widths were increased in proportion to the degree of thread elongation. We then accounted for the actual thread elongation achieved for each individual's threads and for differences in the five species'absolute thread extensibility. The results showed that in four species thread extensibility contributed positively to adhesion. For three species, thread extensibility and droplet volume together explained the mean per droplet adhesion of threads. Models based on these three species show that, as threads were elongated, increasing amounts of potential adhesion were lost to diminished axial fiber extensibility. These models indicate that approximately one-third of an unstretched viscous thread's stickiness accrues from the adhesive recruitment made possible by axial fiber extensibility.
Bumble bees heat up for high quality pollen
Authors: Mapalad Katherine S. , Leu Daniel , Nieh James C.
Published: June 2008

Thermoregulation plays a key role in bee foraging, allowing some species to forage in suboptimal temperatures. Recently, bumble bee thoracic temperature(Tth) has been shown to increase with nectar carbohydrate content. However, pollen is also vital to bees and exhibits a greater than 20-fold range in protein quality. We provide the first demonstration that bee Tth is also correlated with pollen quality. We allowed bumble bee, Bombus impatiens, foragers from two colonies to collect pollen varying in quality (25%, 50%, 75% and 100% by mass mixed with indigestible α-cellulose). We used infrared thermography to measure surface Tth when a forager finished collecting feeder pollen and when she returned to the nest. Foragers significantly elevated their Tth over ambient air temperature while collecting pollen and maintained this elevated Tth upon returning to the nest. On average, foragers increased Tth over ambient by 0.4°C per 25% increase in pollen protein content. Bumble bees can therefore adjust their thoracic temperature according to pollen quality.
Effects of salinity on intestinal bicarbonate secretion and compensatory regulation of acid–base balance inOpsanus beta
Authors: Genz Janet , Taylor Josi R. , Grosell Martin
Published: June 2008

Marine teleosts have extracellular fluids less concentrated than their environment, resulting in continual water loss, which is compensated for by drinking, with intestinal water absorption driven by NaCl uptake. Absorption of Cl– occurs in part by apical Cl–/HCO3– exchange, with HCO3– provided by transepithelial transport and/or by carbonic anhydrase-mediated hydration of endogenous epithelial CO2. Hydration of CO2 also liberates H+,which is transported across the basolateral membrane. In this study, gulf toadfish (Opsanus beta) were acclimated to 9, 35 and 50 ppt. Intestinal HCO3– secretion, water and salt absorption, and the ensuing effects on acid–base balance were examined. Rectal fluid excretion greatly increased with increasing salinity from 0.17±0.05 ml kg–1 h–1 in 9 ppt to 0.70±0.19 ml kg–1 h–1 in 35 ppt and 1.46±0.22 ml kg–1 h–1 in 50 ppt. Rectal fluid composition and excretion rates allowed for estimation of drinking rates, which increased with salinity from 1.38±0.30 to 2.60±0.92 and 3.82±0.58 ml kg–1h–1 in 9, 35 and 50 ppt, respectively. By contrast, the fraction of imbibed water absorbed decreased from 85.9±3.8% in 9 ppt to 68.8±3.2% in 35 ppt and 61.4±1.0% in 50 ppt. Despite large changes in rectal base excretion from 9.3±2.7 to 68.2±20.4 and 193.2±64.9 μmol kg–1 h–1 in 9, 35 and 50 ppt, respectively, acute or prolonged exposure to altered salinities was associated with only modest acid–base balance disturbances. Extra-intestinal, presumably branchial, net acid excretion increased with salinity (62.0±21.0, 229.7±38.5 and 403.1±32.9 μmol kg–1 h–1 at 9, 35 and 50 ppt, respectively),demonstrating a compensatory response to altered intestinal base secretion associated with osmoregulatory demand.
A muscarinic cholinergic mechanism underlies activation of the central pattern generator for locust flight
Authors: Buhl Edgar , Schildberger Klaus , Stevenson Paul A.
Published: June 2008

A central question in behavioural control is how central pattern generators(CPGs) for locomotion are activated. This paper disputes the key role generally accredited to octopamine in activating the CPG for insect flight. In deafferented locusts, fictive flight was initiated by bath application of the muscarinic agonist pilocarpine, the acetylcholine analogue carbachol, and the acetylcholinesterase blocker eserine, but not by nicotine. Furthermore, in addition to octopamine, various other amines including dopamine, tyramine and histamine all induced fictive flight, but not serotonin or the amine-precursor amino acid tyrosine. However, flight initiation was not reversibly blocked by aminergic antagonists, and was still readily elicited by both natural stimulation (wind) and pilocarpine in reserpinized, amine-depleted locusts. By contrast, the muscarinic antagonists atropine and scopolamine reversibly blocked flight initiated by wind, cholinergic agonists, octopamine, and by selective stimulation of a flight-initiating interneurone (TCG). The short delay from TCG stimulation to flight onset suggests that TCG acts directly on the flight CPG, and accordingly that TCG, or its follower cell within the flight generating circuit, is cholinergic. We conclude that acetylcholine acting via muscarinic receptors is the key neurotransmitter in the mechanism underlying the natural activation of the locust flight CPG. Amines are not essential for this, but must be considered as potential neuromodulators for facilitating flight release and tuning the motor pattern. We speculate that muscarinic activation coupled to aminergic facilitation may be a general feature of behavioural control in insects for ensuring conditional recruitment of individual motor programs in accordance with momentary adaptive requirements.
Carbohydrate regulation in relation to colony growth in ants
Authors: Dussutour A. , Simpson S. J.
Published: June 2008

Ants and all social insects are faced with a nutritional challenge: the food entering the colony is brought by only a small number of its workers but is shared among all members of the colony. In this study, we investigated how ants maintain carbohydrates supply at both a collective and an individual level in response to changes in the concentration of available sucrose solution, colony demography and larval growth. We manipulated the concentration of sugar solutions available to ant colonies (dilute, medium and concentrated solutions) over extended periods and measured the capacity of colonies to maintain sugar supply through compensatory feeding. First, we demonstrated that ants regulated carbohydrate intake at a collective and individual level. Initially, ants consumed most and recruited fastest in response to more concentrated than to dilute sugar solutions, but over time this pattern reversed, such that the number of ants that fed and the volume ingested by each ant was a negative function of sugar concentration in the diet. Second, we found that ants became better at regulating their carbohydrate intake with the production of larvae in the nest. When the number of larvae was experimentally doubled, the ants regulated their consumption of carbohydrates more accurately than when the number of adult workers was doubled, suggesting that larvae play an important role in providing nutritional feedback to workers. Finally, we showed that ants defended a carbohydrate `intake target' by allowing them to select among sugar solutions of different concentration.
Female mice respond differently to costly foraging versus food restriction
Authors: Schubert Kristin A. , Vaanholt Lobke M. , Stavasius Fanny , Demas Gregory E. , Daan Serge , Visser G. Henk
Published: June 2008

Experimental manipulation of foraging costs per food reward can be used to study the plasticity of physiological systems involved in energy metabolism. This approach is useful for understanding adaptations to natural variation in food availability. Earlier studies have shown that animals foraging on a fixed reward schedule decrease energy intake and expenditure. However, the extent to which these changes depend on decreased food intake or increased foraging costs per se has never been tested. We manipulated foraging costs per food reward in female Hsd:ICR(CD-1) laboratory mice, comparing animals faced with low (L) and high (H) foraging costs to non-foraging animals receiving a food restriction (R) matched to the intake of H animals. Mice in the H group ran as much as L mice did but ate significantly less. They concurrently reduced daily energy expenditure and resting metabolic rate, decreased the size of major metabolic organs and utilized body fat stores; mass-specific resting metabolic rate did not differ between groups. We found evidence that these alterations in energy balance may carry fitness costs. As a secondary response to our experimental treatment, H females and, eventually, some R females ceased to show signs of estrous cyclicity. Surprisingly, results of an immune challenge with keyhole limpet hemocyanin showed that primary immune response did not differ between L and H groups, and was actually higher in R mice. Our results demonstrate that high foraging costs per se –the combination of high activity and low food intake – have pronounced physiological effects in female mice.
Scaling of muscle architecture and fiber types in the rat hindlimb
Authors: Eng Carolyn M. , Smallwood Laura H. , Rainiero Maria Pia , Lahey Michele , Ward Samuel R. , Lieber Richard L.
Published: June 2008

The functional capacity of a muscle is determined by its architecture and metabolic properties. Although extensive analyses of muscle architecture and fiber type have been completed in a large number of muscles in numerous species, there have been few studies that have looked at the interrelationship of these functional parameters among muscles of a single species. Nor have the architectural properties of individual muscles been compared across species to understand scaling. This study examined muscle architecture and fiber type in the rat (Rattus norvegicus) hindlimb to examine each muscle's functional specialization. Discriminant analysis demonstrated that architectural properties are a greater predictor of muscle function (as defined by primary joint action and anti-gravity or non anti-gravity role)than fiber type. Architectural properties were not strictly aligned with fiber type, but when muscles were grouped according to anti-gravity versusnon-anti-gravity function there was evidence of functional specialization. Specifically, anti-gravity muscles had a larger percentage of slow fiber type and increased muscle physiological cross-sectional area. Incongruities between a muscle's architecture and fiber type may reflect the variability of functional requirements on single muscles, especially those that cross multiple joints. Additionally, discriminant analysis and scaling of architectural variables in the hindlimb across several mammalian species was used to explore whether any functional patterns could be elucidated within single muscles or across muscle groups. Several muscles deviated from previously described muscle architecture scaling rules and there was large variability within functional groups in how muscles should be scaled with body size. This implies that functional demands placed on muscles across species should be examined on the single muscle level.