3,848 research outputs found
AdS Strings with Torsion: Non-complex Heterotic Compactifications
Combining the effects of fluxes and gaugino condensation in heterotic
supergravity, we use a ten-dimensional approach to find a new class of
four-dimensional supersymmetric AdS compactifications on almost-Hermitian
manifolds of SU(3) structure. Computation of the torsion allows a
classification of the internal geometry, which for a particular combination of
fluxes and condensate, is nearly Kahler. We argue that all moduli are fixed,
and we show that the Kahler potential and superpotential proposed in the
literature yield the correct AdS radius. In the nearly Kahler case, we are able
to solve the H Bianchi using a nonstandard embedding. Finally, we point out
subtleties in deriving the effective superpotential and understanding the
heterotic supergravity in the presence of a gaugino condensate.Comment: 42 pages; v2. added refs, revised discussion of Bianchi for N
Descrição do girino de Agalychnis hulli (Anura: Hylidae)
Se recolectaron larvas en la Amazonia Ecuatoriana, las cuales permiten la descripción científica del renacuajo de Agalychnis hulli. El renacuajo es inusual entre los Phyllomedusinae y su morfología externa es más similar a las especies de Hylomantis que a otras especies de Agalychnis, lo que sugiere que la especie bien puede representar un vínculo evolutivo importante entre estos géneros. El renacuajo, que hasta la fecha no ha sido descrito, se puede distinguir de todos los demás renacuajos de Agalychnis por tener un disco oral (i) que se dirige anteroventralmente y se extiende a más de la mitad del ancho del cuerpo, (ii) que se modifica en una estructura corta en forma de embudo, (iii) y que está rodeado por una sola fila de papilas marginales.The collection of larval specimens from Amazonian Ecuador allows for the scientific description of the tadpole of Agalychnis hulli. The tadpole is unusual among Phyllomedusinae and its external morphology appears more similar to species of Hylomantis than other species of Agalychnis, suggesting the species may well represent an important evolutionary link between these genera. The tadpole, which to date has remained undescribed, can be distinguished from all other Agalychnis tadpoles in having an oral disc (i) that is directed anteroventrally and extends to more than half the width of the body, (ii) which is modified into a short funnel- shaped structure, (iii) and surrounded by a single row of marginal papillae.A coleta de espécimes larvais da Amazônia equatoriana permitem a descrição científica do girino de Agalychnis hulli. O girino é incomum entre os Phyllomedusinae e sua morfologia externa parece mais similar à das espécies de Hylomantis do que a de outras espécies de Agalychnis, sugerindo que essa espécie podem representar um importante elo evolutivo entre estes gêneros. O girino, que até hoje não havia sido descrito, pode ser distinguido de todos os outros girinos de Agalychnis por apresentar um disco oral (i) dirigido anteroventralmente e estendendos-e para mais da metade da largura do corpo, (ii) modificado em uma estrutura curta em forma de funil, e (iii) rodeado por uma única fileira de papilas marginais
Method for serial passage of infectious hematopoietic necrosis virus (IHNV) in rainbow trout
Transmission is a fundamental component of pathogen fitness. A better understanding of pathogen transmission can greatly improve disease management. In particular, controlled studies of multiple rounds of natural transmission (i.e. serial passage) can provide powerful epidemiological and evolutionary inferences. However, such studies are possible in only a few systems because of the challenges in successfully initiating and maintaining transmission in the laboratory. Here we developed an efficient and reproducible cohabitation method for conducting controlled experiments investigating the effects of serial passage on infectious hematopoietic necrosis virus (IHNV) in rainbow trout. This method was used to investigate the transmission efficiency and kinetics of viral shedding of IHNV over 3 serial passages. Transmission efficiency decreased from 100 to 62.5% over the passage steps and was associated with a decrease in virus shedding into water. A shift in the peak of viral shedding was also observed, from Day 2 post immersion for passage 0 to at least 24 h later for all subsequent passages. Finally, the characterization of viruses after 1 round of transmission and propagation on cells showed no change in glyco protein (G gene) sequences or viral virulence compared to the ancestral virus stock. The methods developed provide valuable tools for reproducible population-level studies of IHNV epidemiology and evolution
Understanding the interpretation and implementation of social and emotional learning in physical education
Sleep hygiene intervention for youth aged 10 to 18 years with problematic sleep: a before-after pilot study
BACKGROUND: The current study aimed to examine the changes following a sleep hygiene intervention on sleep hygiene practices, sleep quality, and daytime symptoms in youth. METHODS: Participants aged 10–18 years with self-identified sleep problems completed our age-appropriate F.E.R.R.E.T (an acronym for the categories of Food, Emotions, Routine, Restrict, Environment and Timing) sleep hygiene programme; each category has three simple rules to encourage good sleep. Participants (and parents as appropriate) completed the Adolescent Sleep Hygiene Scale (ASHS), Pittsburgh Sleep Quality Index (PSQI), Sleep Disturbance Scale for Children (SDSC), Pediatric Daytime Sleepiness Scale (PDSS), and wore Actical® monitors twice before (1 and 2 weeks) and three times after (6, 12 and 20 weeks) the intervention. Anthropometric data were collected two weeks before and 20 weeks post-intervention. RESULTS: Thirty-three youths (mean age 12.9 years; M/F = 0.8) enrolled, and retention was 100%. ASHS scores significantly improved (p = 0.005) from a baseline mean (SD) of 4.70 (0.41) to 4.95 (0.31) post-intervention, as did PSQI scores [7.47 (2.43) to 4.47 (2.37); p < 0.001] and SDSC scores [53.4 (9.0) to 39.2 (9.2); p < 0.001]. PDSS scores improved from a baseline of 16.5 (6.0) to 11.3 (6.0) post- intervention (p < 0.001). BMI z-scores with a baseline of 0.79 (1.18) decreased significantly (p = 0.001) post-intervention to 0.66 (1.19). Despite these improvements, sleep duration as estimated by Actical accelerometry did not change. There was however a significant decrease in daytime sedentary/light energy expenditure. CONCLUSIONS: Our findings suggest the F.E.R.R.E.T sleep hygiene education programme might be effective in improving sleep in children and adolescents. However because this was a before and after study and a pilot study with several limitations, the findings need to be addressed with caution, and would need to be replicated within a randomised controlled trial to prove efficacy. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN1261200064981
Kentucky Vehicle License Plate Study
This study assesses Kentucky’s options for potentially re-plating all motor vehicles registered in the Commonwealth. The report begins with a background and discussion of Kentucky’s plate production processes, the difference between flat and embossed plates, and the structure of license plate labor at the Kentucky State Reformatory in La Grange. It details current plate production costs and processes, along with fees and production numbers. It evaluates three scenarios for future plate production: flat plate production, a hybrid system with embossed general issue plates and flat specialty plates, and an embossed plate system with in-house printed sheeting. Also included is an analysis of the effects of license plate characteristics on automated license plate reader accuracy, which has implications for automated screening and tolling. From there, the policies and approaches of other states are discussed. The report ends with a discussion of implementation costs, challenges, and strategies for state officials
Constitutive expression of Yes-associated protein (Yap) in adult skeletal muscle fibres induces muscle atrophy and myopathy
Peer reviewedPublisher PD
Neural responses to facial and vocal expressions of fear and disgust
Neuropsychological studies report more impaired responses to facial expressions of fear than disgust in people with amygdala lesions, and vice versa in people with Huntington's disease. Experiments using functional magnetic resonance imaging (fMRI) have confirmed the role of the amygdala in the response to fearful faces and have implicated the anterior insula in the response to facial expressions of disgust. We used fMRI to extend these studies to the perception of fear and disgust from both facial and vocal expressions. Consistent with neuropsychological findings, both types of fearful stimuli activated the amygdala. Facial expressions of disgust activated the anterior insula and the caudate-putamen; vocal expressions of disgust did not significantly activate either of these regions. All four types of stimuli activated the superior temporal gyrus. Our findings therefore (i) support the differential localization of the neural substrates of fear and disgust; (ii) confirm the involvement of the amygdala in the emotion of fear, whether evoked by facial or vocal expressions; (iii) confirm the involvement of the anterior insula and the striatum in reactions to facial expressions of disgust; and (iv) suggest a possible general role for the perception of emotional expressions for the superior temporal gyrus
Characteristics of atmospheric organic and elemental carbon particle concentrations in Los Angeles
A fine particle air monitoring network was operated in the Los Angeles area during 1982. It was found that carbonaceous aerosols accounted for typically 40% of total fine particle mass loadings at most monitoring sites. The ratio of total carbon (TC) to elemental carbon (EC) in ambient samples and in primary source emissions was examined as an indicator of the extent of secondary organic aerosol formation. It was found that TC to EC ratios at all
sites on average are no higher than recent estimates of the TC to EC ratio in primary source emissions. There is little evidence of the sustained summer peak in the ratio of TC to EC that one might expect if greatly enhanced secondary organics production occurs during the photochemical smog season. The TC to EC ratio does rise by the time that air masses reach the prevailing downwind edge of the air basin as would be expected if secondary organics are being formed during air parcel transport, but the extent of that increase is modest. These results suggest that primary particulate carbon emissions were the principal contributor to long-term average fine aerosol carbon concentrations in the Los Angeles area during 1982
Infrared constraints on the dark mass concentration observed in the cluster Abell 1942
We present a deep H-band image of the region in the vicinity of the cluster
Abell 1942 containing the puzzling dark matter concentration detected in an
optical weak lensing study by Erben et al. (2000). We demonstrate that our
limiting magnitude, H=22, would be sufficient to detect clusters of appropriate
mass out to redshifts comparable with the mean redshift of the background
sources. Despite this, our infrared image reveals no obvious overdensity of
sources at the location of the lensing mass peak, nor an excess of sources in
the I-H vs. H colour-magnitude diagram. We use this to further constrain the
luminosity and mass-to-light ratio of the putative dark clump as a function of
its redshift. We find that for spatially-flat cosmologies, background lensing
clusters with reasonable mass-to-light ratios lying in the redshift range 0<z<1
are strongly excluded, leaving open the possibility that the mass concentration
is a new type of truly dark object.Comment: 8 pages, 7 figures. MNRAS submitted (after referee revision
- …