The impact of a vertically transmitted microsporidian, Nosema granulosis on the fitness of its Gammarus duebeni host under stressful environmental conditions

Although purely vertically transmitted parasites are predicted to cause low pathogenicity in their hosts, the effects of such parasites on host fitness under stressful environmental conditions have not previously been assessed. Here, we investigate the effects of Nosema granulosis, a vertically transmitted, microsporidian parasite of the brackish water amphipod Gammarus duebeni, on host growth and survival under conditions of host–host competition and limited food. The parasite had no effect on host survival, but caused a reduction in juvenile growth. Stressful environmental conditions also led to a reduction in G. duebeni growth. However, we found no evidence to support the prediction that parasitized hosts would suffer a greater reduction in fitness than uninfected hosts under adverse environmental conditions. We interpret our results in the context of selection for successful vertical parasite transmission

Economic aspects of the production and marketing of hardy nursery stock

End of Project ReportA census of the Nursery Stock industry, carried out in autumn 1997, valued the sales of plants produced by the industry in 1996 at £18.8m. In the period since a previous census in 1994 field production of nursery stock expanded by 17% while the production of container plants shifted towards the greater use of protected cultivation. Employment in the industry rose by 28% to 912 full time equivalent jobs. Kildare was predominant in the production of containerised plants while Tipperary was the most important county for field production. Together, these two counties produced nearly half the value of the industry. Together with Cork, Dublin, Kilkenny and Wicklow they accounted for three quarters of the value of the industry. The industry was concentrated in that the largest 10% of the nurseries produced 59% of the value of the industry. As nursery size increased, the value of sales output per person rose sharply. Larger nurseries were also more productive per unit area. Exports were valued at £3.45m and imports at £2.22m. The main lines exported were ornamental shrubs followed by liners and deciduous trees. Two thirds of the exports were destined for Great Britain with the remainder going to Northern Ireland. Exporting was even more concentrated than production with the largest 10% of the nurseries providing 83% of the exports. The main imports were deciduous trees and liners. Two thirds of the imports originated from the continent and the remainder were from Great Britain. Small nurseries reported that capital and profitability were the principal factors limiting expansion of their nurseries. Larger nurseries however placed the availability of suitable staff as the main limiting factor. The most common difficulty reported by exporters was the cost of transport and a number of problems relating to the difficulties that individual nurseries or small groups have in supplying a large, discerning and relatively distant market. This underlined the need for increased co-ordination and co-operation in the future

The Irish Hardy Nursery Stock Industry: Recent Trends and Competitive Position.

End of Project ReportTh Irish Hardy Nursery Stock (HNS) industry has grown considerably in recent times. For the industry to maintain this level of growth it must remain competitive, particularly relative to the UK and the Netherlands, Ireland's main trading partners for HNS. Consequently, the objectives of this research were to (i) establish the size and value of the Irish HNS industry in 1999/2000, and (ii) examine the relative competitiveness of the Irish HNS industry, using profitability and value as indicators of competitiveness. A census of the Irish HNS industry was carried out between September 2000 and June 2001 to establish the size and value of the industry. The results of the census showed that the net value of plants produced on Irish nurseries amounted to €30.6m in 1999, an increase of €6.8m from €23.4m at the last census in 1996. In the same period the total area devoted to HNS production also increased from 391 ha in 1997 to 465ha in 1999. Kildare remains the most important county in the industry in terms of value because of the large area devoted to outdoor containerised production and production under protection. In terms of competitiveness, unpaid labour (imputed) had a significant effect on profitability levels for the three countries. When an imputed charge for unpaid labour was included in the analysis, the UK and Ireland had relatively higher Net Nursery Income (NNI) than the Netherlands. However, when the imputed charge for unpaid labour was excluded from the analysis, Ireland and the Netherlands had relatively higher NNI values than the UK. Firm size and mechanisation levels, were examined as possible sources of inter-firm variations in costs of production and profits. Economies of scale appeared to be evident as nursery size increased from `small' to `medium' and dissipated as nursery size increased from `medium' to `large'. This indicated that the minimum economic size for HNS production appeared to be relatively low. Based on the observed relationship between labour productivity and mechanisation levels, it is possible to infer that future mechanisation of the Irish industry may provide a partial solution to labour availability problems. Although the Irish HNS industry showed a competitive cost advantage, the low added value content of the Irish product is not a reassuring sign for the industry. The research revealed that the competitive potential of the industry in the Netherlands, based on relative value-added properties, was ahead of the Irish and UK industries. However, the Netherlands has not fully succeeded in converting this potential into competitive performance in the Irish market for HNS. The Irish HNS industry remains the largest supplier of HNS to the domestic market, although HNS available from the Netherlands was seen as given better value. In order for the Irish industry to remain competitive in the future the competitive strategies which the industry adopts must be re-evaluated. Distinct market segments were observed in the Irish market, which offers potential for a focused competitive strategy, which may suit smaller specialist producers. The critical buying criteria identified and subsequent relative performance of the Irish industry should provide the information, which is required for a competitive strategy of differentiation

The effects of breastfeeding on childhood BMI: a propensity score matching approach

This paper investigates the effect of breastfeeding on childhood body mass index (BMI). We use data from the Millennium Cohort Study (MCS), a nationally representative UK cohort survey, containing detailed infant feeding information, which allow us to explore the effects of a range of breastfeeding variables on the mean BMI of children breastfed for different durations and for exclusive and partial breastfeeding. Using propensity score matching, we find statistically significant influences of breastfeeding on childhood BMI, particularly in older children and when breastfeeding is prolonged and exclusive. The effects of breastfeeding on BMI are small in magnitude but large relative to the mean BMIs of children this age. At this young age, there is not a large difference in BMI between children who are identified as obese and those who are identified as normal weight, so even a small difference in BMI could mean the difference between children being overweight or a healthy weight. We suggest that breastfeeding should be encouraged as part of wider lifestyle interventions in order to help reduce BMI as well as improve other childhood outcomes. This could be important evidence for public health bodies when creating public health guidelines and recommendations

Role of dopamine D1-like receptors in methamphetamine locomotor responses of D2 receptor knockout mice

Behavioral sensitization to psychostimulants manifests as an increased locomotor response with repeated administration. Dopamine systems are accepted to play a fundamental role in sensitization, but the role of specific dopamine receptor subtypes has not been completely defined. This study used the combination of dopamine D2 receptor-deficient mice and a D1-like antagonist to examine dopamine D1 and D2 receptor involvement in acute and sensitized locomotor responses to methamphetamine. Absence of the dopamine D2 receptor resulted in attenuation of the acute stimulant effects of methamphetamine. Mutant and wild-type mice exhibited sensitization that lasted longer within the time period of the challenge test in the mutant animals. Pretreatment with the D1-like receptor antagonist SCH 23390 produced more potent reductions in the acute and sensitized locomotor responses to methamphetamine in D2 receptor-deficient mice than in wild-type mice; however, the expression of locomotor sensitization when challenged with methamphetamine alone was equivalently attenuated by previous treatment with SCH 23390. These data suggest that dopamine D2 receptors play a key role in the acute stimulant and sensitizing effects of methamphetamine and act in concert with D1-like receptors to influence the acquisition of methamphetamine-induced behavioral sensitization, traits that may influence continued methamphetamine use.Fil:Rubinstein, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

How to Undertake a Clinically Relevant Systematic Review in a Rapidly Evolving Field: Magnetic Resonance Angiography

Objectives: The aim was to determine which generations of the evolving technology of magnetic resonance angiography (MRA) are currently of clinical relevance in two clinical applications. Our purpose was to plan a systematic review that would be valuable both to purchasers driven by cost-effectiveness and to practicing clinicians. Methods: Information was gathered from a search of major bibliographic databases, from a short questionnaire sent to 500 U.K. vascular radiologists and vascular surgeons, and from local clinical The authors thank A. Jackson and all those who completed a questionnaire. This work was carried out with the financial support of the Secretary of State for Health under the NHS Health Technology Assessment Programme, project 97/13/04. The views and opinions expressed do not necessarily reflect those of the Secretary of State for Health. In part, this work was undertaken by the Leeds Teaching Hospitals NHS Trust, which received funding from the NHS Executive. The views expressed in this publication are those of the authors and not necessarily those of the NHS Executive.experts. We asked which of the MRA techniques were currently used and, assuming availability, what would be their technique of choice. Results: There were 206 published articles that satisfied preliminary inclusion criteria: 69 discussed 2D time of flight (TOF); 47, 3D TOF; and 38, contrast-enhanced techniques. There were 162 questionnaires returned (60 radiologists, 102 surgeons). Of the total respondents, 77/162 (48%) used MRA in the assessment of carotid artery stenosis; 47/77 (61%) used 2D TOF; 32/77 (42%), 3D TOF; and 26/77 (34%), contrast-enhanced techniques. Thirty-five of 162 (22%) respondents used MRA in the assessment of peripheral vascular disease (PVD); 15/35 (43%) used 2D TOF, 4/35 (11%) used 3D TOF, and 22/35 (63%) used contrast-enhanced techniques. For those wishing to use MRA, contrast-enhanced techniques were the method of choice. Conclusions: The TOF methods that represent earlier generations of the technology remain clinically relevant, and will therefore be included in our systematic review. To ensure complete and relevant coverage in reviews of other evolving technologies, it would be advisable to obtain data for guidance in a similar way

Use of magnetic resonance angiography to select candidates with recently symptomatic carotid stenosis for surgery: systematic review

Objective To determine if sufficient evidence exists to support the use of magnetic resonance angiography as a means of selecting patients with recently symptomatic high grade carotid stenosis for surgery. Design Systematic review of published research on the diagnostic performance of magnetic resonance angiography, 1990-9. Main outcome measures Performance characteristics of diagnostic test. Results 126 potentially relevant articles were identified, but many articles failed to examine die performance of magnetic resonance angiography as a diagnostic test at the surgical decision thresholds used in major clinical trials on endarterectomy. 26 articles were included in a meta-analysis that showed a maximal joint sensitivity and specificity of 99% (95% confidence interval 98% to 100%) for identifying 70-99% stenosis and 90% (81% to 99%) for identifying 50-99% stenosis. Only four articles evaluated contrast enhanced magnetic resonance angiography. Conclusions Magnetic resonance angiography is accurate for selecting patients for carotid endarterectomy at the surgical decision thresholds established in the major endarterectomy trials, but the evidence is not very robust because of the heterogeneity of the studies included. Research is to determine the diagnostic performance of the most recent developments in magnetic resonance angiography, including contrast enhanced techniques, as well as to assess the impact of magnetic resonance angiography on surgical decision making and outcomes

Functional ecology of advance regeneration in relation to light in boreal forests

This paper reviews aspects of the functional ecology of naturally established tree seedlings in the boreal forests of North America with an emphasis on the relationship between light availability and the growth and survival of shade tolerant conifers up to pole size. Shade tolerant conifer species such as firs and spruces tend to have a lower specific leaf mass, photosynthetic rate at saturation, live crown ratio, STAR (shoot silhouette area to total needle surface area ratio), and root to shoot ratio than the shade intolerant pines. The inability of intolerant species such as the pines and aspen to survive in shade appears to be mainly the result of characteristics at the shoot, crown, and whole-tree levels and not at the leaf level. Although firs and spruces frequently coexist in shaded understories, they do not have identical growth patterns and crown architectures. We propose a simple framework based on the maximum height that different tree species can sustain in shade, which may help managers determine the timing of partial or complete harvests. Consideration of these functional aspects of regeneration is important to the understanding of boreal forest dynamics and can be useful to forest managers seeking to develop or assess novel silvicultural systems

Cleaning optimization for reduced chemical usage

The use of dilute SC-1 (NH40H:H202:H20) chemistry cleaning processes for particle removal from silicon surfaces has been investigated. Dilute chemistries can be highly effective, especially when high- frequency acoustic energy (megasonics) is applied. The high particle removal efficacy of the dilute chemistry processes presumably arises due to increased double layer effects caused by reduced ionic strength. Dilute chemistry SC- I solutions exhibit somewhat reduced efficacy for removal of certain light organics; however, when dilute SC-1 is used along with other pre-gate cleaning steps (e.g. HF, SC-2, and piranha), then the overall cleaning sequence is quite effective. In addition to providing robust cleaning processes, dilute chemistries also result in significantly lower chemical and rinse water usage. Waste water treatment requirements are also lessened when dilute chemistry cleaning solutions are employed

Seeking an "i-deal" balance: Schedule-flexibility i-deals as mediating mechanisms between supervisor emotional support and employee work and home performance

Requests for flexible work practices have become commonplace, with the aim of helping employees perform more effectively in both their private and work lives. One path for employees to secure flexible work is through the negotiation of individualized work arrangements, also known as “i-deals”. This study provides valuable insights into the nomological network of scheduleflexibility i-deals by drawing on the Conservation of Resources (COR) theory. We propose that, via resource accumulation, schedule-flexibility i-deals are a mechanism through which the emotional support of supervisors promotes employees' family performance and reduces deviant work behaviors. Drawing further on the COR framework, we examine two boundary conditions that guide employees' resource investment: perception of family-friendly environment and prosocial motivation. We collected multi-source data from employees working in South America and tested our hypotheses using structural equation modeling. Our results provide support for the key mediating role of schedule-flexibility i-deals. Moreover, the indirect relationship between supervisors' emotional support and family performance through schedule-flexibility i-deals is stronger in family-friendly organizational contexts, as well as when employees are prosocially motivated. Our results also show that, contrary to the expected effect, when prosocial motivation is high, employee supervisors' emotional support is positively linked to deviant behaviors. We contribute to the literature by emphasizing the roles of perceived resources at the levels of leaders (i.e., supervisors' emotional support), context (supervisors' perceptions of a family-friendly environment), and individuals (employees' prosocial motivation). We demonstrate the importance of these resources in establishing and sustaining schedule-flexibility i-deal