Collaborative Pacific Halibut, Hippoglossus stenolepis, Bycatch Control by Canada and the United States

ABSTRACT—Bycatch mortality of Pacific halibut, Hippoglossus stenolepis, in nontarget fisheries is composed primarily of immature fish, and substantial reductions in yield to directed halibut fisheries result from this bycatch. Distant-water bottomtrawl fleets operating off the North American coast, beginning in the mid 1960’s, experienced bycatch mortality of over 12,000 t annually. Substantial progress on reducing this bycatch was not achieved until the of extension fisheries jurisdictions by the United States and Canada in 1977. Bycatch began to increase again during the expansion of domestic catching capacity for groundfish, and by the early 1990’s it had returned to levels seen during the period of foreign fishing. Collaborative action by Canada and the United States through the International Pacific Halibut Commission has resulted in substantial reductions in bycatch mortality in some areas. Methods of control have operated at global, fleet, and individual vessel levels. We evaluate the hierarchy of effectiveness for these control measures and identify regulatory needs for optimum effects. New monitoring technologies offer the promise of more cost-effective approaches to bycatch reduction

Abusive Romantic Relationships among Adolescent and Young Adult Mothers

The associations between intimate partner violence (IPV) and mental health among adolescents and young adults were compared in the current study. The connections among marriage status, Latino heritage and abusive experiences were also analyzed. 672 women including 282 adolescents between the ages of 14 and 19 and 390 young adults aged 20 or 21 participated in the study. Significant correlations were discovered between anxiety and depression symptoms among adolescents while anxiety and IPV, anxiety and depression, depression and IPV were all significantly correlated among young adults. In addition, IPV and marriage status as well as marriage status and Latina heritage were significantly correlated among young adults. No significant findings came from linear or logistic regressions conducted with the adolescent data but, among young adults, linear regressions with IPV as the dependent variable led to significant relationships between IPV and marital status. In addition, logistic regressions indicated significant links in the young adult data between IPV and depression and anxiety symptoms. IPV during adolescence may be a different phenomenon than adult IPV or mental health symptoms may be latent variables that are reported later in life. Prevention programs for adolescents as well as young adults are encouraged.

Chemical enrichment in very low-metallicity environments: Bootes I

We present different chemical evolution models for the ultrafaint dwarf galaxy Bootes I. We either assume that the galaxy accretes its mass through smooth infall of gas of primordial chemical composition (classical models) or adopt mass accretion histories derived from the combination of merger trees with semi-analytical modelling (cosmologically-motivated models). Furthermore, we consider models with and without taking into account inhomogeneous mixing in the ISM within the galaxy. The theoretical predictions are then compared to each other and to the body of the available data. From this analysis, we confirm previous findings that Bootes I has formed stars with very low efficiency but, at variance with previous studies, we do not find a clear-cut indication that supernova explosions have sustained long-lasting galactic-scale outflows in this galaxy. Therefore, we suggest that external mechanisms such as ram pressure stripping and tidal stripping are needed to explain the absence of neutral gas in Bootes I today.Comment: 13 pages, 11 figures, accepted for publication in MNRA

The Bifurcated Age-Metallicity Relation of Milky Way Globular Clusters and its Implications For the Accretion History of the Galaxy

We use recently derived ages for 61 Milky Way (MW) globular clusters (GCs) to show that their age-metallicity relation (AMR) can be divided into two distinct, parallel sequences at [Fe/H] \ga -1.8. Approximately one-third of the clusters form an offset sequence that spans the full range in age ($\sim 10.5$--13 Gyr), but is more metal rich at a given age by $\sim 0.6$ dex in [Fe/H]. All but one of the clusters in the offset sequence show orbital properties that are consistent with membership in the MW disk. They are not simply the most metal-rich GCs, which have long been known to have disk-like kinematics, but they are the most metal-rich clusters at all ages. The slope of the mass-metallicity relation (MMR) for galaxies implies that the offset in metallicity of the two branches of the AMR corresponds to a mass decrement of 2 dex, suggesting host galaxy masses of M_{*} \sim 10^{7-8} \msol for GCs that belong to the more metal-poor AMR. We suggest that the metal-rich branch of the AMR consists of clusters that formed in-situ in the disk, while the metal-poor GCs were formed in relatively low-mass (dwarf) galaxies and later accreted by the MW. The observed AMR of MW disk stars, and of the LMC, SMC and WLM dwarf galaxies are shown to be consistent with this interpretation, and the relative distribution of implied progenitor masses for the halo GC clusters is in excellent agreement with the MW subhalo mass function predicted by simulations. A notable implication of the bifurcated AMR, is that the identical mean ages and spread in ages, for the metal rich and metal poor GCs are difficult to reconcile with an in-situ formation for the latter population.Comment: 16 pages, 9 figures, accepted for publication in MNRA

Changing recycling behaviour: an evaluation of attitudes and behaviour to recycling in the Western Riverside area of London

Key to improving recycling performance in the UK is the need to more effectively engage the public and improve levels of participation. The research described in this paper combines quantitative and qualitative analysis of attitudinal and behavioural changes as part of an evaluation project to measure the impact of a multi-faceted waste awareness and education campaign in the Western Riverside Waste Authority area of central London. Analysis links attitudinal and behavioural responses to infrastructure provision and performance indicators for each area surveyed, as well as socio-demographic indicators. This paper presents the results and analysis of the attitudes, motivations and behaviours of a representative profile of households from this area of central London, in an attempt to better understand how behavioural change can be achieved and recycling targets met

Magnetic rocks - their effect on compass use and navigation in Tasmania

The common and uncritical use of the magnetic compass by orienteers and walkers in Tasmania may lead to severe error. Rocks in many localities are intensely magnetised and their local field can strongly influence the pointing of a compass. Repeated observation against transect alignments may be necessary to minimise the problems

The nature of jointing, Tasman Peninsula, southern Tasmania

Existing literature describing the joints in high dolerite cliffs and at the Tessellated Pavement on the Tasman Peninsula offers conflicting views concerning their origin. Recent writers have preferred a tectonic origin. Although regional structures do affect both pavement and cliffrocks, these are not pervasive at outcrop scale. The rock pillars of the high cliffs are true, thermally produced columns, and their nature can be demonstrated by direct inspection of polygons. Polygon faces are not readily identified in collections of joint measurements, but some common orientations have been united in cliff exposure to yield ragged lineaments. This yields the illusion of more recent tectonic control, although many such orientations are clearly at least Jurassic in age. The apparently regular patterns of the pavements are regionally variable, and joint continuity and orientation are complex functions of lithology, bed thickness and pre-stressing, with new joints forming due to relaxation and weathering processes. Pavement joints are generally very recent although they too replicate much older structural trends controlled by east-west shears. Pavement ornamentation provides fine examples of physical and chemical weathering processes