812 research outputs found
Evaluation of an online youth ambassador program to promote mental health
To evaluate an online Youth Ambassador (YA) program designed to promote internet resources for mental health in an adolescent population, 56 YAs and 357 of their Year 10 peers from 11 Tasmanian schools completed e-mental health questionnaires before and after the YAs attended a single workshop session. The workshops, which were delivered in the high school setting, were either facilitated or self-directed. Self-reported awareness of e-mental health resources increased among both YAs and their peers. The peer group also showed increased frequency of recommending help-seeking to others. There were no differences in outcomes for facilitated or self-directed workshop formats. The results suggest that an online YA program delivered in school is useful in improving mental health awareness for workshop participants. While their Year 10 peer groups also showed increased awareness, this could not necessarily be attributed to the participation of all 11 schools in the YA program
Search for supersolidity in 4He in low-frequency sound experiments
We present results of the search for supersolid 4He using low-frequency,
low-level mechanical excitation of a solid sample grown and cooled at fixed
volume. We have observed low frequency non-linear resonances that constitute
anomalous features. These features, which appear below about 0.8 K, are absent
in 3He. The frequency, the amplitude at which the nonlinearity sets in, and the
upper temperature limit of existence of these resonances depend markedly on the
sample history.Comment: Submitted to the Quantum Fluids and Solids Conf. Aug. 2006 Kyot
UK export performance research - review and implications
Previous research on export performance has been criticized for being a mosaic of autonomous endeavours and for a lack of theoretical development. Building upon extant models of export performance, and a review and analysis of research on export performance in the UK for the period 1990-2005, an integrated model of export performance is developed and theoretical explanations of export performance are put forward. It is suggested that a multi-theory approach to explaining export performance is viable. Management and policy implications for the UK emerging from the review and synthesis of the literature and the integrated model are discussed
Low Temperature Shear Modulus Changes in Solid 4-He and Connection to Supersolidity
Superfluidity, liquid flow without friction, is familiar in helium. The first
evidence for "supersolidity", its analogue in quantum solids, came from recent
torsional oscillator (TO) measurements involving 4-He. At temperatures below
200 mK, TO frequencies increased, suggesting that some of the solid decoupled
from the oscillator. This behavior has been replicated by several groups but
solid 4-He does not respond to pressure differences and persistent currents and
other signatures of superflow have not been seen. Both experiments and theory
indicate that defects are involved. These should also affect the solid's
mechanical behavior and so we have measured the shear modulus of solid 4-He at
low frequencies and strains. We observe large increases below 200 mK, with the
same dependence on measurement amplitude, 3-He impurity concentration and
annealing as the decoupling seen in TO experiments. This unusual elastic
behavior is explained in terms of a dislocation network which is pinned by 3-He
at the lowest temperatures but becomes mobile above 100 mK. The frequency
changes in TO experiments appear to be related to the motion of these
dislocations, perhaps by disrupting a possible supersolid state.Comment: 18 pages, 4 figues, Supplementary Informatio
Recent Salmon Declines: A Result of Lost Feeding Opportunities Due to Bad Timing?
As the timing of spring productivity blooms in near-shore areas advances due to warming trends in global climate, the selection pressures on out-migrating salmon smolts are shifting. Species and stocks that leave natal streams earlier may be favoured over later-migrating fish. The low post-release survival of hatchery fish during recent years may be in part due to static release times that do not take the timing of plankton blooms into account. This study examined the effects of release time on the migratory behaviour and survival of wild and hatchery-reared coho salmon (Oncorhynchus kisutch) using acoustic and coded-wire telemetry. Plankton monitoring and near-shore seining were also conducted to determine which habitat and food sources were favoured. Acoustic tags (n = 140) and coded-wire tags (n = 266,692) were implanted into coho salmon smolts at the Seymour and Quinsam Rivers, in British Columbia, Canada. Differences between wild and hatchery fish, and early and late releases were examined during the entire lifecycle. Physiological sampling was also carried out on 30 fish from each release group. The smolt-to-adult survival of coho salmon released during periods of high marine productivity was 1.5- to 3-fold greater than those released both before and after, and the fish's degree of smoltification affected their downstream migration time and duration of stay in the estuary. Therefore, hatchery managers should consider having smolts fully developed and ready for release during the peak of the near-shore plankton blooms. Monitoring chlorophyll a levels and water temperature early in the spring could provide a forecast of the timing of these blooms, giving hatcheries time to adjust their release schedule
Melting of a 2D Quantum Electron Solid in High Magnetic Field
The melting temperature () of a solid is generally determined by the
pressure applied to it, or indirectly by its density () through the equation
of state. This remains true even for helium solids\cite{wilk:67}, where quantum
effects often lead to unusual properties\cite{ekim:04}. In this letter we
present experimental evidence to show that for a two dimensional (2D) solid
formed by electrons in a semiconductor sample under a strong perpendicular
magnetic field\cite{shay:97} (), the is not controlled by , but
effectively by the \textit{quantum correlation} between the electrons through
the Landau level filling factor =. Such melting behavior, different
from that of all other known solids (including a classical 2D electron solid at
zero magnetic field\cite{grim:79}), attests to the quantum nature of the
magnetic field induced electron solid. Moreover, we found the to increase
with the strength of the sample-dependent disorder that pins the electron
solid.Comment: Some typos corrected and 2 references added. Final version with minor
editoriol revisions published in Nature Physic
Age and growth of the smooth hammerhead shark, Sphyrna zygaena, in the Eastern Equatorial Atlantic Ocean, using vertebral sections
The smooth hammerhead shark Sphyrna zygaena (Sphyrnidae) is regularly caught as bycatch in pelagic
longline fisheries, but is one of the least studied of all pelagic sharks. Recently, ICCAT (International Commission for
the Conservation of Atlantic Tunas) issued recommendations underlining the need for more studies on the life history
parameters of this and other pelagic shark species. To this end, the age and growth of S. zygaena were studied in the
Eastern Equatorial Atlantic Ocean, in an area where growth parameters were not yet available for this species. Data
from 139 specimens, caught between June and September 2009, ranging in size from 136 to 233 cm fork length (FL),
were analysed. Preliminary trials were carried out to assess the most efficient growth band enhancement technique.
These indicated that sectioning the vertebrae into 500 μm sections followed by staining with crystal violet produced
the best results. Growth models were fitted using the traditional von Bertalanffy growth equation and a modification of
this equation using a known size at birth. Growth models were compared using the Akaike information criterion (AIC).
The von Bertalanffy growth equation seemed to be the most adequate model to describe growth in this species, with
resulting growth parameters of L inf = 272 cm FL, k = 0.06 year for males and L inf = 285 cm FL, k = 0.07 year for
females. In the first four years of life, S. zygaena grows 25 cm per year on average, but its growth slows down in later
life. Future stock assessment models should incorporate these age and growth parameters for species management and
conservation.info:eu-repo/semantics/publishedVersio
Representations of sport in the revolutionary socialist press in Britain, 1988–2012
This paper considers how sport presents a dualism to those on the far left of the political spectrum. A long-standing, passionate debate has existed on the contradictory role played by sport, polarised between those who reject it as a bourgeois capitalist plague and those who argue for its reclamation and reformation. A case study is offered of a political party that has consistently used revolutionary Marxism as the basis for its activity and how this party, the largest in Britain, addresses sport in its publications. The study draws on empirical data to illustrate this debate by reporting findings from three socialist publications. When sport did feature it was often in relation to high profile sporting events with a critical tone adopted and typically focused on issues of commodification, exploitation and alienation of athletes and supporters. However, readers’ letters, printed in the same publications, revealed how this interpretation was not universally accepted, thus illustrating the contradictory nature of sport for those on the far left
Comparison between surface-reading and cross-section methods using sagittal otolith for age determination of the marbled sole Pseudopleuronectes yokohamae
To find an appropriate method for age determination in the marbled sole Pseudopleuronectes yokohamae in Tokyo Bay, Japan, sagittal otoliths of 1,343 individuals were observed by surface-reading and cross-section methods and the results were compared. Opaque zones occurred once a year and were regarded as annuli in both methods. The surface-reading method sometimes provided a lower count of the number of annuli than the cross-section method, and the frequency of this discrepancy was highest in older fish (males above 5 years, females above 4 years). The oldest female fish was estimated to be age 10 years by the cross-section method but 8 years by the surface-reading method. The cross-section method could provide a more accurate estimate of age and is therefore likely to be indispensable to estimations of longevity. In contrast, the surface-reading method is superior in terms of cost and time efficiency but is likely to underestimate the ages of older fish. However, growth equations based on age estimated by the surface-reading method were sufficiently accurate if males ?5 years and females ?4 years were combined as specific, single age groups of 5+ and 4+, respectively
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