bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sensory coding of nest-site value in honeybee swarms
Authors: Seeley Thomas D. , Visscher P. Kirk 
Published: November 2008

SUMMARY
This study investigates the first stage of the decision-making process of a honeybee swarm as it chooses a nest site: how a scout bee codes the value of a potential nest site in the waggle dances she produces to represent this site. We presented honeybee swarms with a two-alternative choice between a high-value site and a medium-value site and recorded the behavior of individually identifiable scout bees as they reported on these two alternatives. We found that bees performed equally lengthy inspections at the two sites, but that, on the swarm cluster, they performed more dance circuits per bee for the high-value site. We also found that there was much individual-level noise in the coding of site value, but that there were clear population-level differences in total dance circuits produced for the two sites. The first bee to find a site had a high probability of reporting the site with a waggle dance, regardless of its value. This discoverer-should-dance phenomenon may help ensure that a swarm gives attention to all discovered sites. There was rapid decay in the dance response; the number of dance circuits produced by a bee after visiting a site decreased linearly over sequential visits, and eventually each bee ceased visiting her site. This decay, or `leakage', in the accumulation of bees at a site improves a swarm's decision-making ability by helping a swarm avoid making fast-decision errors.
Better mate in the shade: enhancement of male mating behaviour in the cabbage butterfly, Pieris rapae crucivora, in a UV-rich environment
Authors: Obara Yoshiaki , Koshitaka Hisaharu , Arikawa Kentaro 
Published: November 2008

SUMMARY
Ultraviolet (UV) vision is widespread in a variety of animals, playing important roles in behaviours such as foraging and reproduction. Despite accumulated information about UV vision and UV-dependent behaviours of animals, little is known about the effect of temporal changes and local variations in UV light on UV-dependent behaviour. Here we report the mating behaviour of male cabbage butterfly, Pieris rapae crucivora, in environments with varying content of UV light. We first confirmed that the relative UV content is higher in shaded places than in sunny places. We furthermore arranged experimental areas with varying UV contents in the field,where we compared three aspects of male mating behaviour: visual localization of females, female-searching flight and copulation success rate. In all aspects males performed more actively in UV-rich environments: males searched females for longer, approached females preferentially in the shade and copulated there more frequently. Apparently, female-searching males detect females more easily in a UV-rich environment. The present findings should be taken into consideration when UV-dependent behaviours, visual mate choice in particular, are studied.
The connection between landscapes and the solar ephemeris in honeybees
Authors: Towne William F. , Moscrip Heather 
Published: November 2008

SUMMARYHoneybees connect the sun's daily pattern of azimuthal movement to some aspect of the landscape around their nests. In the present study, we ask what aspect of the landscape is used in this context – the entire landscape panorama or only sectors seen along familiar flight routes. Previous studies of the solar ephemeris memory in bees have generally used bees that had experience flying a specific route, usually along a treeline, to a feeder. When such bees were moved to a differently oriented treeline on overcast days,the bees oriented their communicative dances as if they were still at the first treeline, based on a memory of the sun's course in relation to some aspect of the site, possibly the familiar route along the treeline or possibly the entire landscape or skyline panorama. Our results show that bees lacking specific flight-route training can nonetheless recall the sun's compass bearing relative to novel flight routes in their natal landscape. Specifically, we moved a hive from one landscape to a differently oriented twin landscape, and only after transplantation under overcast skies did we move a feeder away from the hive. These bees nonetheless danced accurately by memory of the sun's course in relation to their natal landscape. The bees'knowledge of the relationship between the sun and landscape, therefore, is not limited to familiar flight routes and so may encompass, at least functionally,the entire panorama. Further evidence suggests that the skyline in particular may be the bees' preferred reference in this context.
Foraging behavior of humpback whales: kinematic and respiratory patterns suggest a high cost for a lunge
Authors: Goldbogen Jeremy A. , Calambokidis John , Croll Donald A. , Harvey James T. , Newton Kelly M. , Oleson Erin M. , Schorr Greg , Shadwick Robert E. 
Published: November 2008

SUMMARY
Lunge feeding in rorqual whales is a drag-based feeding mechanism that is thought to entail a high energetic cost and consequently limit the maximum dive time of these extraordinarily large predators. Although the kinematics of lunge feeding in fin whales supports this hypothesis, it is unclear whether respiratory compensation occurs as a consequence of lunge-feeding activity. We used high-resolution digital tags on foraging humpback whales (Megaptera novaengliae) to determine the number of lunges executed per dive as well as respiratory frequency between dives. Data from two whales are reported,which together performed 58 foraging dives and 451 lunges. During one study,we tracked one tagged whale for approximately 2 h and examined the spatial distribution of prey using a digital echosounder. These data were integrated with the dive profile to reveal that lunges are directed toward the upper boundary of dense krill aggregations. Foraging dives were characterized by a gliding descent, up to 15 lunges at depth, and an ascent powered by steady swimming. Longer dives were required to perform more lunges at depth and these extended apneas were followed by an increase in the number of breaths taken after a dive. Maximum dive durations during foraging were approximately half of those previously reported for singing (i.e. non-feeding) humpback whales. At the highest lunge frequencies (10 to 15 lunges per dive), respiratory rate was at least threefold higher than that of singing humpback whales that underwent a similar degree of apnea. These data suggest that the high energetic cost associated with lunge feeding in blue and fin whales also occurs in intermediate sized rorquals.
Compass gait mechanics account for top walking speeds in ducks and humans
Authors: Usherwood James R. , Szymanek Katie L. , Daley Monica A. 
Published: November 2008

SUMMARY
The constraints to maximum walking speed and the underlying cause of the walk–run transition remains controversial. However, the motions of the body and legs can be reduced to a few mechanical principles, which, if valid,impose simple physics-based limits to walking speed. Bipedal walking may be viewed as a vaulting gait, with the centre of mass (CoM) passing over a stiff stance leg (an `inverted pendulum'), while the swing leg swings forward (as a pendulum). At its simplest, this forms a `compass gait' walker, which has a maximum walking speed constrained by simple mechanics: walk too fast, or with too high a step length, and gravity fails to keep the stance foot attached to the floor. But how useful is such an extremely reductionist model? In the present study, we report measurements on a range of duck breeds as example unspecialized, non-planar, crouch-limbed walkers and contrast these findings with previous measurements on humans, using the theoretical framework of compass gait walking. Ducks walked as inverted pendulums with near-passive swing legs up to relative velocities around 0.5, remarkably consistent with the theoretical model. By contrast, top walking speeds in humans cannot be achieved with passive swing legs: humans, while still constrained by compass gait mechanics, extend their envelope of walking speeds by using relatively high step frequencies. Therefore, the capacity to drive the swing leg forward by walking humans may be a specialization for walking, allowing near-passive vaulting of the CoM at walking speeds 4/3 that possible with a passive(duck-like) swing leg.
Episodic swimming behavior in the nematodeC. elegans
Authors: Ghosh Rajarshi , Emmons Scott W. 
Published: November 2008

SUMMARYControlling the choice of behavioral output is a central function of the nervous system. Here we document a novel spontaneous behavioral transition in C. elegans locomotion. Upon transfer of the nematode from a solid surface into a liquid environment, swimming occurs in two phases: an initial,1–2 h phase of continuous swimming, followed by a second phase during which swimming is episodic. During the second, episodic phase, periods of active swimming alternate in a highly regular fashion with a quiescent state lasting for several minutes. We analyzed the nature of the quiescent state and the basis for spontaneous switching between swimming and quiescence. The transition from swimming to quiescence is promoted by acetylcholine signaling and initially during quiescence body wall muscles are in a state of contraction. After the first minute, quiescent worms respond to prodding and resume swimming normally. The major command interneurons that control the locomotory circuits are not necessary for quiescence since swimming–quiescence cycling occurs after ablation of command interneurons. However, when subsets of neurons including the command interneurons are killed, the switching pattern becomes less regular,suggesting that a timer governing switching may lie within circuitry controlling motor neurons. The results show that the motor circuits have a tendency to switch spontaneously between active and inactive behavioral states. This property might be important to the animal in a uniform environment where sensory input is invariant.
Experimental study of the effect of some geometric variables and number of nozzles on the performance of a subsonic air—air ejector
Authors: Meakhail T A , Zien Y , Elsallak M , AbdelHady S 
Published: November 2008

An ejector is a pumping device that uses a high-speed primary fluid jet to entrain a secondary stream. The pumping action is due to the exchange of momentum between the primary and secondary streams. The air ejectors are widely used in mixing systems and many engineering applications. The purpose of the present work is to study experimentally the effects of using different numbers of nozzles with various geometric variables on the performance of the air ejector. The test rig, which is designed particularly for this study, is constructed so that the overall performance of the air ejector can be measured under various operating conditions. To the best knowledge of the authors, there is no published work concerning the study of all the geometric variables with different numbers of nozzles, showing their effect on the ejector performance. The experimental investigations consist of the performance measurements for 52 ejectors. They are classified into three main groups The following conclusions were drawn
Glyceryl ether monooxygenase resembles aromatic amino acid hydroxylases in metal ion and tetrahydrobiopterin dependence
Authors: Watschinger Katrin , Keller Markus A. , Hermetter Albin , Golderer Georg , Werner-Felmayer Gabriele , Werner Ernst R. 
Published: November 2008

Abstract
Glyceryl ether monooxygenase is a tetrahydrobiopterin-dependent membrane-bound enzyme which catalyses the cleavage of lipid ethers into glycerol and the corresponding aldehyde. Despite many different characterisation and purification attempts, so far no gene and primary sequence have been assigned to this enzyme. The seven other tetrahydrobiopterin-dependent enzymes can be divided in the family of aromatic amino acid hydroxylases – comprising phenylalanine hydroxylase, tyrosine hydroxylase and the two tryptophan hydroxylases – and into the three nitric oxide synthases. We tested the influences of different metal ions and metal ion chelators on glyceryl ether monooxygenase, phenylalanine hydroxylase and nitric oxide synthase activity to elucidate the relationship of glyceryl ether monooxygenase to these two families. 1,10-Phenanthroline, an inhibitor of non-heme iron-dependent enzymes, was able to potently block glyceryl ether monooxygenase as well as phenylalanine hydroxylase, but had no effect on inducible nitric oxide synthase. Two tetrahydrobiopterin analogues, N5-methyltetrahydrobiopterin and 4-aminotetrahydrobiopterin, had a similar impact on glyceryl ether monooxygenase activity, as has already been shown for phenylalanine hydroxylase. These observations point to a close analogy of the role of tetrahydrobiopterin in glyceryl ether monooxygenase and in aromatic amino acid hydroxylases and suggest that glyceryl ether monooxygenase may require a non-heme iron for catalysis.
Expansion of CD133-Expressing Liver Cancer Stem Cells in Liver-Specific Phosphatase and Tensin Homolog Deleted on Chromosome 10-Deleted Mice
Authors: Rountree C. Bart , Ding Wei , He Lina , Stiles Bangyan 
Published: November 2008

Abstract
PTEN (phosphatase and tensin homolog deleted on chromosome 10) is a lipid phosphatase that regulates mitogenic signaling pathways, and deficiency of PTEN results in cell proliferation, survival, and malignancy. Murine liver-specific Pten deletion models develop liver malignancy by 12 months of age. Using this model, we describe a population of CD133+ liver cancer stem cells isolated during the chronic injury phase of disease progression and before primary carcinoma formation. We performed immunohistochemistry and flow cytometry isolation using livers from 3- and 6-month-old PtenloxP/loxP; Alb−Cre+ mice (mutants) and controls. CD133+CD45− nonparenchymal (NP) cells were analyzed for gene expression profile and protein levels. Single CD133+CD45− oval cells were isolated for clonal expansion and tumor analysis. Cultured and freshly isolated liver CD133+CD45− and CD133−CD45− NP cells were injected into immune-deficient and immune-competent mice. In mutant mice, the NP fraction increased in CD133+CD45− cells in 3- and 6-month-old Pten-deleted animals compared with controls. Clone lines expanded from single CD133+CD45− cells demonstrated consistent liver progenitor cell phenotype, with bilineage gene expression of hepatocyte and cholangiocyte markers. CD133+ cells from expanded clone lines formed robust tumors in immune-deficient and immune-competent mice. Furthermore, freshly isolated CD133+CD45− NP liver cells from 6-month-old mutants formed tumors in vivo, and CD133−CD45− NP cells did not. Consistent with a cancer stem cell phenotype, CD133+ cells demonstrate resistance to chemotherapy agents compared with CD133− cells. CD133+CD45− nonparenchymal cells from chronic injury PtenloxP/loxP; Alb−Cre+ mice represent a bipotent liver progenitor cell population with cancer stem cell phenotype.
Code choice in Hong Kong
Authors: Yee Ho Judy Woon 
Published: November 2008

China resumed its sovereignty over Hong Kong in 1997. Since then drastic changes in this former British colony have occurred. One of these changes is a shift in language policy, from bilingualism (Cantonese and English) to trilingualism (Cantonese, English and Putonghua). The present study is aimed at investigating tertiary students’ use of Cantonese, English and Putonghua on a daily basis, analysing the roles and functions of each language and discussing how these may impact on language policy and language education.Research instruments included 52 students’ language diaries and written analyses, 51 hours of audio-recordings of verbal exchanges, and focus group semi-structured interviews. Results show that the students’ speech repertoire mainly consists of two languages: Cantonese and English and their various mixes. Cantonese is used to ensure understanding, consolidate solidarity and maintain social cohesion. The English-Cantonese mix has become a more powerful identity marker for educated people in Hong Kong than pure Cantonese. English and its supplement with Cantonese are often used in the domain of education. The majority of students seldom use Putonghua in everyday life, but there is a strong instrumental motivation to learn it. Measures are suggested to facilitate a more successful move from bilingualism to trilingualism.
Protective Factors in the Lives of Bisexual Adolescents in North America
Authors: Saewyc Elizabeth M. , Homma Yuko , Skay Carol L. , Bearinger Linda H. , Resnick Michael D. , Reis Elizabeth 
Published: November 2008

Objectives. We compared protective factors among bisexual adolescents with those of heterosexual, mostly heterosexual, and gay or lesbian adolescents. Methods. We analyzed 6 school-based surveys in Minnesota and British Columbia. Sexual orientation was measured by gender of sexual partners, attraction, or self-labeling. Protective factors included family connectedness, school connectedness, and religious involvement. General linear models, conducted separately by gender and adjusted for age, tested differences between orientation groups. Results. Bisexual adolescents reported significantly less family and school connectedness than did heterosexual and mostly heterosexual adolescents and higher or similar levels of religious involvement. In surveys that measured orientation by self-labeling or attraction, levels of protective factors were generally higher among bisexual than among gay and lesbian respondents. Adolescents with sexual partners of both genders reported levels of protective factors lower than or similar to those of adolescents with same-gender partners. Conclusions. Bisexual adolescents had lower levels of most protective factors than did heterosexual adolescents, which may help explain their higher prevalence of risky behavior. Social connectedness should be monitored by including questions about protective factors in youth health surveys.
Correlates of Heterosexual Anal Intercourse Among At-Risk Adolescents and Young Adults
Authors: Lescano Celia M. , Houck Christopher D. , Brown Larry K. , Doherty Glenn , DiClemente Ralph J. , Fernandez M. Isabel , Pugatch David , Schlenger William E. , Silver Barbara J. 
Published: November 2008

Objectives. We sought to learn what factors are associated with anal intercourse among adolescents and young adults. We examined demographic, behavioral, relationship context, attitudinal, substance use, and mental health correlates of recent heterosexual anal intercourse among adolescents and young adults who reported engaging in recent unprotected sex. Methods. Among 1348 at-risk adolescents and young adults aged 15 to 21 years in 3 US cities, we assessed sexual risk behavior with each sexual partner in the past 90 days. Data were collected from 2000 to 2001. Results. Recent heterosexual anal intercourse was reported by 16% of respondents. Females who engaged in anal intercourse were more likely to be living with a sexual partner, to have had 2 or more partners, and to have experienced coerced intercourse. For males, only a sexual orientation other than heterosexual was a significant predictor of engaging in heterosexual anal intercourse. Conclusions. Our findings document the prevalence of heterosexual anal intercourse among adolescents and young adults who had recent unprotected sex. Among females, the variables associated with anal intercourse relate to the context and power balance of sexual relationships. Different influences for males and females suggest different foci for interventions.
Neighborhood Characteristics and Change in Depressive Symptoms Among Older Residents of New York City
Authors: Beard John R. , Cerdá Magda , Blaney Shannon , Ahern Jennifer , Vlahov David , Galea Sandro 
Published: November 2008

Objectives. We investigated the relationship between the depressive symptoms of older adults over time and the characteristics of the neighborhoods in which they live. Methods. We surveyed a random sample of 1325 New York City residents aged 50 years or older in 2005 and conducted 808 follow-up interviews in 2007. We assessed the compositional characteristics of the respondents' neighborhoods at a census-tract level and determined the relationships between these characteristics and changes in respondents' depressive symptoms. Results. In multivariable models that adjusted for individual-level covariates including income, a range of neighborhood characteristics predicted worsening depressive symptoms. Factor analysis suggested that these characteristics operated in 3 clusters: neighborhood socioeconomic influences, residential stability, and racial/ethnic composition, with positive neighborhood socioeconomic influences being significantly protective against worsening symptoms. Life stressors, personality trait neuroticism, African American race, and daily baseline contact with social networks were also associated with worsening symptoms. Conclusions. An older adult's neighborhood of residence is an important determinant of his or her mental health. Those making efforts to improve mental health among the elderly need to consider the role of residential context in improving or impairing mental health.
Intimate Partner Violence, Maternal Stress, Nativity, and Risk for Maternal Maltreatment of Young Children
Authors: Taylor Catherine A. , Guterman Neil B. , Lee Shawna J. , Rathouz Paul J. 
Published: November 2008

Objectives. We examined the associations of intimate partner violence (IPV) and maternal risk factors with maternal child maltreatment risk within a diverse sample of mothers. Methods. We derived the study sample (N = 2508) from the Fragile Families and Child Well-Being Study. We conducted regression analyses to examine associations between IPV, parenting stress, major depression, key covariates, and 4 proxy variables for maternal child maltreatment. Results. Mothers reported an average of 25 acts of psychological aggression and 17 acts of physical aggression against their 3-year-old children in the year before the study, 11% reported some act of neglect toward their children during the same period, and 55% had spanked their children during the previous month. About 40% of mothers had experienced IPV by their current partner. IPV and maternal parenting stress were both consistent risk factors for all 4 maltreatment proxy variables. Although foreign-born mothers reported fewer incidents of child maltreatment, the IPV relative risk for child maltreatment was greater for foreign-born than for US-born mothers. Conclusions. Further integration of IPV and child maltreatment prevention and intervention efforts is warranted; such efforts must carefully balance the needs of adult and child victims.
Impact of the Family Health Program on Infant Mortality in Brazilian Municipalities
Authors: Aquino Rosana , de Oliveira Nelson F. , Barreto Mauricio L. 
Published: November 2008

Objectives. We evaluated the effects of the Family Health Program (FHP), a strategy for reorganization of primary health care at a nationwide level in Brazil, on infant mortality at a municipality level. Methods. We collected data on FHP coverage and infant mortality rates for 771 of 5561 Brazilian municipalities from 1996 to 2004. We performed a multivariable regression analysis for panel data with a negative binomial response by using fixed-effects models that controlled for demographic, social, and economic variables. Results. We observed a statistically significant negative association between FHP coverage and infant mortality rate. After we controlled for potential confounders, the reduction in the infant mortality rate was 13.0%, 16.0%, and 22.0%, respectively for the 3 levels of FHP coverage. The effect of the FHP was greater in municipalities with a higher infant mortality rate and lower human development index at the beginning of the study period. Conclusions. The FHP had an important effect on reducing the infant mortality rate in Brazilian municipalities from 1996 to 2004. The FHP may also contribute toward reducing health inequalities.