Fluid Outflows From Venus Impact Craters: Analysis From Magellan Data

Many impact craters on Venus have unusual outflow features originating in or under the continuous ejecta blankets and continuing downhill into the surrounding terrain. These features clearly resulted from flow of low-viscosity fluids, but the identity of those fluids is not clear. In particular, it should not be assumed a priori that the fluid is an impact melt. A number of candidate processes by which impact events might generate the observed features are considered, and predictions are made concerning the rheological character of flows produced by each mechanism. A sample of outflows was analyzed using Magellan images and a model of unconstrained Bingham plastic flow on inclined planes, leading to estimates of viscosity and yield strength for the flow materials. It is argued that at least two different mechanisms have produced outflows on Venus: an erosive, channel-forming process and a depositional process. The erosive fluid is probably an impact melt, but the depositional fluid may consist of fluidized solid debris, vaporized material, and/or melt

A collaborative approach to learning programming: a hybrid learning model

The use of cooperative working as a means of developing collaborative skills has been recognised as vital in programming education. This paper presents results obtained from preliminary work to investigate the effectiveness of Pair Programming as a collaborative learning strategy and also its value towards improving programming skills within the laboratory. The potential of Problem Based Learning as a means of further developing cooperative working skills along with problem solving skills is also examined and a hybrid model encompassing both strategies outlined

One-year follow-up of family versus child CBT for anxiety disorders: Exploring the roles of child age and parental intrusiveness.

ObjectiveTo compare the relative long-term benefit of family-focused cognitive behavioral therapy (FCBT) and child-focused cognitive behavioral therapy (CCBT) for child anxiety disorders at a 1-year follow-up.MethodThirty-five children (6-13 years old) randomly assigned to 12-16 sessions of family-focused CBT (FCBT) or child-focused CBT (CCBT) participated in a 1-year follow-up assessment. Independent evaluators, parents, and children rated anxiety and parental intrusiveness. All were blind to treatment condition and study hypotheses.ResultsChildren assigned to FCBT had lower anxiety scores than children assigned to CCBT on follow-up diagnostician- and parent-report scores, but not child-report scores. Exploratory analyses suggested the advantage of FCBT over CCBT may have been evident more for early adolescents than for younger children and that reductions in parental intrusiveness may have mediated the treatment effect.ConclusionFCBT may yield a stronger treatment effect than CCBT that lasts for at least 1 year, although the lack of consistency across informants necessitates a circumspect view of the findings. The potential moderating and mediating effects considered in this study offer interesting avenues for further study

Status of MSX in Chesapeake Bay

Oystermen in lower Chesapeake Bay survived the ravages of Dermocystidium during some hot summers in the past decade only to be scourged by a new disease which appeared in 1969. We had learned to live with Dermocystidium by avoiding infected seed and limiting the number of hot summers oysters were held in infested areas. Now we have the more difficult problem of adjusting to MSX which is a devastating killer of oysters

Status of diseases of oysters in Chesapeake Bay

Oysters in lower Chesapeake Bay survived the ravages of Dermocystidium during some hot summers in the past decade only to be scourged by a new disease (MSX) which appeared in 1959. We had learned to live with Dermocystidium by avoiding infected seed and limiting the number of hot summers oysters were held in infested areas. Now we are faced with the more difficult problem of adjusting to MSX, which is a devastating killer of oysters. The beginning of a new season of planting seed is an appropriate time to review our knowledge of teh various diseases of oysters

Occurrence of MSX in live oysters in Rappahannock River

Sampling data

Referential Questioning: A Strategy for Enhancing the Reader-Text Interaction

What follows is a rationale for the use of the Referential Questioning strategy. Question types are described and examples provided

The stability of food intake between adolescence and adulthood: a 21-year follow-up

Studies of the diet of adolescents in the UK demonstrate that dietary habits known to be detrimental to health in adulthood are evident at an early age. For example, Gregory et al (2000) found 4-18 year olds in the UK to have a frequent consumption of fatty and sugary foods and low consumption of fruit and vegetables. Concerns have therefore been expressed regarding the diet of children and adolescents and the continuation of these dietary habits into adulthood (HEA, 1995; Gaziano, 1998). This study aimed to investigate the extent to which these concerns may be justified by determining the stability of food intake of a group of adolescents followed up 21 years later in adulthood. The investigation involved 202 individuals from whom dietary data were collected in 1979-80 (mean age 11.6 years) (Hackett et al. 1984) and again in 2000-1 (mean age 32.5 years). Dietary data were collected at both time-points using two 3 d estimated food diaries followed by an interview to determine portion sizes using the method considered most appropriate at the time, i.e. calibrated food models in 1979-80 and a photographic food atlas (Nelson et al. 1997) in 2000-1. Foods consumed were allocated to one, or a combination of, the five food groups of the ‘Balance of Good Health’ food selection guide (HEA, 1994) according to Gatenby et al. (1995). The weight of food eaten from each of the five food groups was calculated (percentage of total weight of food consumed) and Pearson correlation coefficients generated to provide an estimate of the stability of food intake. The HEA guide advises that a balanced diet should consist of around 33% fruit and vegetables, 33% bread, other cereals and potatoes, 8% foods containing fat and/or sugar, 12% meat, fish and alternatives and 15% milk and dairy products (Gatenby et al. 1995). A shift in the group’s food intake towards the recommendations had occurred with age, most notably with a decrease in foods containing fat and/or sugar and an increase in fruit and vegetables. Nevertheless, at both ages, intakes of foods containing fat and/or sugar, meat, fish and alternatives were higher, and fruit, vegetables, bread, other cereals and potatoes lower than currently recommended. In addition, although there was significant evidence of tracking of relative intake of bread, cereals and potatoes (P<0.01), fruit and vegetables (P<0.01), and meat, fish and alternatives (P=0.02) between 11.6 and 32.5 years, the correlations were not strong. In conclusion, food intake patterns had changed considerably from early adolescence through to adulthood in a direction more in line with the current recommendations. The predictive value of an adolescent’s food intake of their intake in adulthood was found to be significant, but not strong. Further investigations will consider the extent to which this is influenced by factors such as social class, gender and educational level, as well as assessing tracking in terms of relative nutrient intakes