Salinity effects on glucose uptake and catabolism in the obligately psychrophilic marine bacterium Vibrio marinus

Studies on the effects of various salinities on the uptake and catabolism of glucose in Vibrio marinus MP-1 revealed several significant shifts in total uptake and respiration as the cells were subjected to increasingly greater concentrations of NaCl. As the salinity increased from 0.30 to 1.0 M NaCl, there was a decrease in the C₆/C₁ (CO₂) ratio. The resulting patterns suggests that the relative participation of the hexose monophosphate pathway in glucose catabolism was altered. This pathway is apparently shut down in the region of the minimum-growth salinity, and may be related to growth limitation at rower salinities. The shift in C₆/C₁ ratio was not affected by changing the incubation temperature, nor was it dependent specifically on the presence of Na⁺ or Cl^-. As the salinity increased from 0.15 to 0.30 M NaCl, there was a shift in the total uptake patterns which suggests the formation and loss of metabolic by-products derived from the first, second, sixth, and presumably fifth carbons of glucose.This paper was taken in part from a dissertation by the senior author, submitted in partial fulfillment of the requirement for the Ph.D. degree, Oregon State University, Corvallis. Published as technical paper No. 3647, Oregon Agricultural Experiment Station.     

Local mate competition,sex ratio and clutch size in bethylid wasps

Summary Parasitoid wasps of the family Bethylidae lay groups of eggs on the larvae of beetles and moths. The larvae develop together and pupate in the vicinity of the host. On hatching, the majority of copulations are between siblings leading to a high degree of local mate competition. Sex ratio theory predicts that as the number of individuals developing on a host increases, the population sex ratio will become progressively more female biassed. A comparative study of sex ratios across the family supports this prediction.     

Energy expended on growth and gonad output in the ribbed musselAulacomya ater

Length/weight relationships have been computed for shell, flesh and byssus ofAulacomya ater (Molina) and energy values used to convert the weights to energy equivalents. Shell accounts for some 26% of total body energy, while the contribution of the byssus declines from 15 to 8% during growth. Observations of juvenile growth rates have been used to generate a Gompertz growth equation which predicts attainment of maximum length (90 mm) after 11 years. Reproductive condition has been assessed by monitoring seasonal fluctuations in the flesh weight of standard-sized individuals, calculated from monthly length/weight regressions. There appear to be three spawnings, of variable date and intensity, each year. From the above data, annual energy expenditure on growth and gonad output has been calculated for individuals of various sizes. The ratio of total production to biomass is a declining clining function of shell length, dropping from 29.5 at 5 mm to 0.8 at 85 mm. The proportion of total production expended on gamete output increases steadily from 25% at attainment of maturity (15 mm) to 81% at 85 mm length. The considerable effects of changing size composition on the amount and type of production in natural populations are discussed.     

Housing association and local authority provision in rural housing markets: a Mid‐Wales case study

Over the last decade or so, rural housing problems in Britain have become an important focus of attention both for researchers and planners. Inaccessibility to adequate housing is a significant component of the more all‐embracing problems of rural deprivation. The rented sector is of particular relevance to the amelioration of these problems, but the supply has been increasingly restricted both in the private and in the public sector. Great stress has therefore been laid on the ability of housing associations to provide rented sector housing. This paper investigates the work of one particular housing association in Mid‐Wales — Cymdeithas Tai Dyffryn Teifi (CTDT) and assesses the degree of complementarity achieved with housing provision by the local councils operating in the same rural locality. The particular areas of effectiveness of a housing association in this context are thereby evaluated.     

Motorcycle fuel tanks and pelvic fractures: A motorcycle fuel tank syndrome

Objective: Pelvic injuries are a serious and commonly occurring injury to motorcycle riders involved in crashes, yet there has been limited research investigating the mechanisms involved in these injuries. This study aimed to investigate the mechanisms involved in pelvic injuries to crashed motorcyclists.

Method: This study involved in-depth crash investigation and 2 convenience-based data sets were used. These data sets investigated motorcycle crashes in the Sydney, Newcastle, and Adelaide regions. Participants included motorcycle riders who had crashed either on a public road or private property within the study areas. The mechanism of injury and the type of injuries were investigated.

Results: The most frequent cause of pelvic injuries in crashed motorcyclists was due to contact with the motorcycle fuel tank during the crash (85%). For riders who had come into contact with the fuel tank, the injury types were able to be grouped into 3 categories based on the complexity of the injury. The complexity of the injury appeared to increase with impact speed but this was a nonsignificant trend. The pelvic injuries that did not occur from contact with the fuel tank in this sample differed in asymmetry of loading and did not commonly involve injury to the bladder. They were commonly one-sided injuries but this differed based on the point of loading; however, a larger sample of these injuries needs to be investigated.

Conclusion: Overall improvements in road safety have not been replicated in the amelioration of pelvic injuries in motorcyclists and improvements in the design of crashworthy motorcycle fuel tanks appear to be required.