Optimizing Circular Side-Resonators to Reduce Computer Fan Noise

One of the main noise sources in computers are the cooling fans. Tonal noise at the rotational frequency of the fan, the blade passing frequency (BPF) and its higher harmonics are important in fan noise. So called 'side-resonators' integrated in the duct of an in-duct axial fan cause an impedance change in the duct and, having proper dimensions and correct position, act as an acoustic mirror reflecting the noise back to the fan. As a result, noise emitted from the computer can be reduced. In this paper, a model describing viscothermal wave propagation in the duct and side-resonator is outlined. The model can be used to determine the resonator dimension and position to optimally reflect noise near the BPF. The developed model is compared with the models for prismatic tube and cylindrical resonators and the physical differences between these three resonators are explained. Preliminary results of a parameter study are presented. The results point out that the range and magnitude of the effective frequency band of a resonator setup can be successfully manipulated by changing the different dimensions of the setup

Institution-wide peer mentoring: Benefits for mentors

Extensive research has shown the benefits of mentoring, including peer mentoring, for higher education students, especially in their first year. However, few studies have focussed exclusively on the outcomes for the mentors themselves. This paper reports the findings of data gathered over three years about a university-wide peer mentoring program. Benefits identified by 858 mentors were coded inductively and four major categories emerged: altruistic, cognitive, social and personal growth. The findings have implications for the promotion of mentor programs to administrators and to prospective mentors. The study provides evidence that university-wide peer mentoring programs offer multiple positive outcomes for the mentors involved, and potentially for higher education institutions administering and supporting such programs

Accelerated HIV testing for PMTCT in maternity and labour wards is vital to capture mothers at a critical point in the programme at district level

TORONTO AIDS Conference 200

Identification and quantification of point sources of surface water contamination in fruit culture in the Netherlands

Measurements of pesticide concentrations in surface water by the water boards show that they have decreased less than was expected from model calculations. Possibly, the implementation of spray drift reducing techniques is overestimated in the model calculation. The impact of point sources is probably underestimated. A project was initiated for the quantification and qualification of possible point sources in Dutch fruit culture. From a survey it was concluded that the majority of fruit growers do not posses the mandatory equipment regarding filling and cleaning of sprayers. This creates a potential environmental risk for surface water contamination. Further research is focused on: internal and external cleaning of sprayers, environmental impact of the washings, discharge of transport water from fruit sorting installations, and bioremediation systems for processing contaminated water

Structural Response of Shells to Shock and Detonation Loading

Part I: theory. Part II: shock loading of a thin aluminum tube. Part III: the GALCIT detonation tube

Parental perception of weight and weight-related behaviour in 2- to 4-year-old children in the eastern part of the Netherlands

Parental perception of weight status and weight-related behaviour of their toddler was determined through a questionnaire survey in child health care centres (CHCs). Complete data on weight, length, sex and age were available for 635 of 682 children (93.1%). The median age of the children was 37.0 months (range 24–56 months). Of all 635 children, 76.5% were normal weight, 16.2% underweight and 7.2% overweight. Parents’ perception of the weight of their child compared with their peers was moderately related to the actual weight status. Of the parents of overweight and underweight children, 87.0% and 89.3%, respectively, were not concerned. Only the parents’ perception of the amount of food eaten by their child was significantly related to the weight status. The primary goal of CHC workers should be to create parental awareness in case of their child being overweight or underweight and to support them in accomplishing a healthy lifestyle

Preventing overweight and improving parenting skills from birth to age 3 years: preliminary results

Background. Parenting has been associated with child weight status. This study aims to evaluate the effects on parenting skills and BMI-SDS of the BBOFT+ overweight prevention program, compared to care-as-usual (CAU). Method. In a cluster-randomized trial, 2500 parents participated. Parent-reported weight and length were used. Parenting was measured with subscales control and reinforcement of the parenting strategies for eating and activity scale (PEAS) and the warmth subscale from the Child Rearing Questionnaire. Results. The first univariate analyses show that at age 15 months, no statistically significant differences in BMI- SDS, parental control, reinforcement or warmth were found between the BBOFT+ and the CAU group. Further cluster analyses need to be conducted. Results from age 36 months will be presented during the conference, which will include all subscales of the PEAS and an assessment of parenting styles. Conclusion. The intervention does not seem to have an effect on BMI-SDS or parenting

Contact-dependent killing by cytotoxic T lymphocytes is insufficient for EL4 tumor regression in vivo

Immunotherapies are an emerging strategy for treatment of solid tumors. Improved understanding of the mechanisms employed by cytotoxic T lymphocytes (CTLs) to control tumors will aid in the development of immunotherapies. CTLs can directly kill tumor cells in a contact-dependent manner or may exert indirect effects on tumor cells via secretion of cytokines. Here we aim to quantify the importance of these mechanisms in murine thymoma EL4/EG7 cells. We developed an agent-based model (ABM) and an ordinary differential equation (ODE) model of tumor regression after adoptive transfer of a population of CTLs. Models were parameterized based on in vivo measurements of CTL infiltration and killing rates applied to EL4/EG7 tumors and OTI T cells. We quantified whether infiltrating CTLs are capable of controlling tumors through only direct, contact-dependent killing. Both models agreed that the low measured killing rate of CTLs in vivo was insufficient to cause tumor regression. In our ABM we also simulated CTL production of the cytokine interferon gamma (IFNγ) in order to explore how an antiproliferative effect of IFNγ might aid CTLs in tumor control. In this model IFNγ substantially reduced tumor growth compared to direct killing alone. Collectively these data demonstrate that contact-dependent killing is insufficient for EL4 regression in vivo and highlight the potential importance of cytokine-induced antiproliferative effects in T cell-mediated tumor control.Toxicolog