The effect of transient overloads on the stress-rupture of glass fibre reinforced polymers

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Effect of Stocking Rate on Growing Juvenile Sunshine Bass, Morone chrysops × M. saxatilis, in an Outdoor Biofloc Production System

The biofloc technology production system is a production intensifying management strategy used primarily for culturing tilapia and penaeid shrimp, both of which can consume the biofloc. Other fish can be grown in biofloc systems because the biofloc serves to maintain water quality, metabolizing the ammonia excreted by intensively fed fish. A dose-response study was conducted in an outdoor biofloc system to begin quantifying the stocking rate-production function for sunshine bass, Morone chrysops x M. saxatilis, advanced fingerlings. Sunshine bass (2.9 ± 0.2 g/fish) were stocked into tanks at 50 to 250 fish/m2 in 50 fish/m2 increments. After 94 days, gross yields ranged from 1.4 to 3.1 kg/m3 and were independent of stocking rate. Harvested fish were separated into two size groups: smaller than 115 mm total length (target fish) and larger than 115 mm TL (jumper fish). Target fish increased linearly from 62% to 93% and jumpers decreased linearly from 38% to 7% of the population, respectively, as stocking rate increased. The outdoor biofloc system offers potential for intensifying the production of advanced sunshine bass fingerlings, but feed consumption appeared to be impeded by high total suspended solids concentrations. Further research is needed to optimize stocking rates and solids management

Hypoxia Affects Performance Traits and Body Composition of Juvenile Hybrid Striped Bass (Morone chrysops x M. saxatilis)

Performance traits and body composition of juvenile hybrid striped bass (Morone chrysops x M. saxatilis) in response to hypoxia were evaluated in replicate tanks maintained at constant dissolved oxygen concentrations that averaged 23.0 ± 2.3%, 39.7 ± 3.0%, and 105.5 ± 9.5% dissolved oxygen saturation. Fish were fed a commercially formulated feed daily to apparent satiation. Total feed intake and fish growth and yield increased linearly in response to increased dissolved oxygen concentration. Nutrient utilization was reduced significantly only at the greatest level of hypoxia. With the exception of whole-body protein content, whole body compositional indices and nutrient retention efficiencies were linearly related to dissolved oxygen concentration. Results demonstrate that as hypoxia becomes more severe, juvenile hybrid striped bass feed intake is reduced, which affects growth and nutrient retention

Hypoxia affects performance traits and body composition of juvenile hybrid striped bass (Morone chrysops x M. saxatilis)

Performance traits and body composition of juvenile hybrid striped bass (Morone chrysops x M. saxatilis) in response to hypoxia were evaluated in replicate tanks maintained at constant dissolved oxygen concentrations that averaged 23.0 ± 2.3%, 39.7 ± 3.0%, and 105.5 ± 9.5% dissolved oxygen saturation. Fish were fed a commercially formulated feed daily to apparent satiation. Total feed intake and fish growth and yield increased linearly in response to increased dissolved oxygen concentration. Nutrient utilization was reduced significantly only at the greatest level of hypoxia. With the exception of whole-body protein content, whole body compositional indices and nutrient retention efficiencies were linearly related to dissolved oxygen concentration. Results demonstrate that as hypoxia becomes more severe, juvenile hybrid striped bass feed intake is reduced, which affects growth and nutrient retention

Hepatic Transcriptomic and Metabolic Responses of Hybrid Striped Bass (Morone saxatilis × Morone chrysops) to Acute and Chronic Hypoxic Insult

Striped bass (Morone saxatilis), white bass (Morone chrysops), and their hybrid are an important group of fish prized for recreational angling in the United States, and there and abroad as a high-value farmed fish. Regardless of habitat, it is not uncommon for fish of the genus Morone to encounter and cope with conditions of scarce oxygen availability. Previously, we determined that hybrid striped bass reared under conditions of chronic hypoxia exhibited reduced feed intake, lower lipid and nutrient retention, and poor growth. To better understand the molecular mechanisms governing these phenotypes, in the present study, we examined the transcriptomic profiles of hepatic tissue in hybrid striped bass exposed to chronic hypoxia (90 days at 25% oxygen saturation) and acute hypoxia (6 h at 25% oxygen saturation). Using high-throughput RNA-seq, we found that over 1400 genes were differentially expressed under disparate oxygen conditions, with the vast majority of transcriptional changes occurring in the acute hypoxia treatment. Gene pathway and bioenergetics analyses revealed hypoxia-mediated perturbation of genes and gene networks related to lipid metabolism, cell death, and changes in hepatic mitochondrial content and cellular respiration. This study offers a more comprehensive view of the temporal and tissue-specific transcriptional changes that occur during hypoxia, and reveals new and shared mechanisms of hypoxia tolerance in teleosts

Etching effects during the chemical vapor deposition of (100) diamond

Current theories of CVD growth on (100) diamond are unable to account for the numerous experimental observations of slow-growing, locally smooth (100)(2×1)(100)(2×1) films. In this paper we use quantum mechanical calculations of diamond surface thermochemistry and atomic-scale kinetic Monte Carlo simulations of deposition to investigate the efficacy of preferential etching as a mechanism that can help to reconcile this discrepancy. This etching mechanism allows for the removal of undercoordinated carbon atoms from the diamond surface. In the absence of etching, simulated growth on the (100)(2×1)(100)(2×1) surface is faster than growth on the (110) and (111) surfaces, and the (100) surface is atomically rough. When etching is included in the simulations, the (100) growth rates decrease to values near those observed experimentally, while the rates of growth on the other surfaces remain largely unaffected and similar to those observed experimentally. In addition, the etching mechanism promotes the growth of smooth (100) surface regions in agreement with numerous scanning probe studies. © 1999 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70606/2/JCPSA6-111-9-4291-1.pd

Statutory Assessment of the class? Supporting the additional needs of the learning context

This paper considers issues of funding of support for students facing difficulties in learning, and the role of assessment and labelling within this process. It explores the tensions within this process using a Foucauldian framework, and from the key perspectives of social justice and rights. Drawing on a range of literature it identifies the focus upon the individual within assessment processes around the world, and then considers in detail the strengths and weaknesses of the current form of Statutory Assessment of Special Educational Needs within England. The paper proposes an alternative funding system that resolves shortcomings within the individual approach and the English system. It suggests that a Class Funding Approach could build on a notion of justice for all, reduce the opportunities for wide variations in provision, and minimise the negative impact of current dividing practices

'Instead of "closing down" at our ages… we’re thinking of exciting and challenging things to do': older people’s microadventures outdoors on (e-)bikes

This paper explores how people aged 50 and over, who were returning to cycling as part of an eight-week health and wellbeing trial, created their own cycling microadventures. Applying a stage model of the process of adventure to qualitative data generated from personal diaries and focus groups, we examine how older people anticipated and prepared for their microadventures, the challenges and discoveries they experienced, the benefits they gained and how electrically assisted ‘e-bikes’ can provide further opportunities for adventure. We conclude that cycles are a mode uniquely placed to facilitate microadventures and that e-bikes, in particular, offer further potential to enable older people to (re-)connect with place and other people. But, while this type of activity can provide benefits in terms of health and wellbeing, we argue that more supportive physical and social infrastructure is required to provide opportunities for more people to undertake microadventures close to their homes

Concepts of Cardiac Development in Retrospect

Recent research, enabled by powerful molecular techniques, has revolutionized our concepts of cardiac development. It was firmly established that the early heart tube gives rise to the left ventricle only, and that the remainder of the myocardium is recruited from surrounding mesoderm during subsequent development. Also, the cardiac chambers were shown not to be derived from the entire looping heart tube, but only from the myocardium at its outer curvatures. Intriguingly, many years ago, classic experimental embryological studies reached very similar conclusions. However, with the current scientific emphasis on molecular mechanisms, old morphological insights became underexposed. Since cardiac development occurs in an architecturally complex and dynamic fashion, molecular insights can only fully be exploited when placed in a proper morphological context. In this communication we present excerpts of important embryological studies of the pioneers of experimental cardiac embryology of the previous century, to relate insights from the past to current observations