The J-machine multicomputer Noakes, Michael D.; Wallach, Deborah A.; Dally, William J.
Computer architecture news,
05/1993, Letnik:
21, Številka:
2
Journal Article
The MIT J-Machine multicomputer has been constructed to study the role of a set of primitive mechanisms in providing efficient support for parallel computing. Each J-Machine node consists of an ...integrated multicomputer component, the Message-Driven Processor (MDP), and 1 MByte of DRAM. The MDP provides mechanisms to support efficient communication, synchronization, and naming. A 512 node J-Machine is operational and is due to be expanded to 1024 nodes in March 1993. In this paper we discuss the design of the J-Machine and evaluate the effectiveness of the mechanisms incorporated into the MDP. We measure the performance of the communication and synchronization mechanisms directly and investigate the behavior of four complete applications.
Run for your life Noakes, Timothy; Spedding, Michael
Nature,
07/2012, Letnik:
487, Številka:
7407
Journal Article
Recenzirano
Odprti dostop
Humans evolved to run. This helps to explain our athletic capacity and our susceptibility to modern diseases, argue Timothy Noakes and Michael Spedding.
Little is known about the amount and infectiousness of influenza virus shed into exhaled breath. This contributes to uncertainty about the importance of airborne influenza transmission. We screened ...355 symptomatic volunteers with acute respiratory illness and report 142 cases with confirmed influenza infection who provided 218 paired nasopharyngeal (NP) and 30-minute breath samples (coarse >5-μm and fine ≤5-μm fractions) on days 1–3 after symptom onset. We assessed viral RNA copy number for all samples and cultured NP swabs and fine aerosols. We recovered infectious virus from 52 (39%) of the fine aerosols and 150 (89%) of the NP swabs with valid cultures. The geometric mean RNA copy numbers were 3.8 × 10⁴/30-minutes fine-, 1.2 × 10⁴/30-minutes coarse-aerosol sample, and 8.2 × 10⁸ per NP swab. Fine- and coarse-aerosol viral RNA were positively associated with body mass index and number of coughs and negatively associated with increasing days since symptom onset in adjusted models. Fine-aerosol viral RNA was also positively associated with having influenza vaccination for both the current and prior season. NP swab viral RNA was positively associated with upper respiratory symptoms and negatively associated with age but was not significantly associated with fine- or coarse-aerosol viral RNA or their predictors. Sneezing was rare, and sneezing and coughing were not necessary for infectious aerosol generation. Our observations suggest that influenza infection in the upper and lower airways are compartmentalized and independent.
Advancing mate choice studies in salmonids Auld, Heather L.; Noakes, David L. G.; Banks, Michael A.
Reviews in fish biology and fisheries,
1/6, Letnik:
29, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Mate choice in most organisms is not random, but determined by a suite of interacting traits and environmental factors. While the selective pressures underlying differences in mate choice between ...species, populations, individuals and even within individuals has been gaining interest, there still remains unexplained variation in mate preferences especially in non-model systems. Despite being of social, environmental and economic importance there is comparatively little known about how salmonids and other tetraploids make mate choice decisions in the wild and the resultant reproductive success (i.e. the number of offspring which survive to sexual maturity). Resolving questions related to salmonid mate choice is of particular importance given that humans have been supplementing salmon populations through aquaculture for decades. Despite these efforts, hatchery produced fish have lower reproductive success relative to their wild counterparts and salmon populations are declining. Most studies on mate choice and reproductive success in salmonids focus on body size and major histocompatibility complex based choice. However, mate choice can also be affected by other factors including other genetic factors, predation risk and social environment. Here, we (a) synthesize what is presently known about mate choice and reproductive success in salmonids, (b) identify gaps in knowledge and areas where there is a lack of consensus in results, and (c) suggest interdisciplinary ways of advancing our understanding of mate choice in salmonids and other polyploids.
The use of cloth face coverings and face masks has become widespread in light of the COVID-19 pandemic. This paper presents a method of using low cost wirelessly connected carbon dioxide (CO2) ...sensors to measure the effects of properly and improperly worn face masks on the concentration distribution of exhaled breath around the face. Four types of face masks are used in two indoor environment scenarios. CO2 as a proxy for exhaled breath is being measured with the Sensirion SCD30 CO2 sensor, and data are being transferred wirelessly to a base station. The exhaled CO2 is measured in four directions at various distances from the head of the subject, and interpolated to create spatial heat maps of CO2 concentration. Statistical analysis using the Friedman’s analysis of variance (ANOVA) test is carried out to determine the validity of the null hypotheses (i.e., distribution of the CO2 is same) between different experiment conditions. Results suggest CO2 concentrations vary little with the type of mask used; however, improper use of the face mask results in statistically different CO2 spatial distribution of concentration. The use of low cost sensors with a visual interpolation tool could provide an effective method of demonstrating the importance of proper mask wearing to the public.
Uncertainty about the importance of influenza transmission by airborne droplet nuclei generates controversy for infection control. Human challenge-transmission studies have been supported as the most ...promising approach to fill this knowledge gap. Healthy, seronegative volunteer 'Donors' (n = 52) were randomly selected for intranasal challenge with influenza A/Wisconsin/67/2005 (H3N2). 'Recipients' randomized to Intervention (IR, n = 40) or Control (CR, n = 35) groups were exposed to Donors for four days. IRs wore face shields and hand sanitized frequently to limit large droplet and contact transmission. One transmitted infection was confirmed by serology in a CR, yielding a secondary attack rate of 2.9% among CR, 0% in IR (p = 0.47 for group difference), and 1.3% overall, significantly less than 16% (p<0.001) expected based on a proof-of-concept study secondary attack rate and considering that there were twice as many Donors and days of exposure. The main difference between these studies was mechanical building ventilation in the follow-on study, suggesting a possible role for aerosols.
Abstract Objective This study aimed to test whether yeast-derived beta 1,3/1,6 glucan can prevent the occurrence or reduce the severity of upper respiratory tract infection (URTI) and modulate innate ...immune responses during winter months in community dwelling older adults. Methods This was a double-blind placebo-controlled trial of community-dwelling adults aged 50 to 70 years randomised to once daily beta 1,3/1,6 glucan (Wellmune 250 mg daily; n=50) or identical placebo capsule (n=50) over 90 days during winter. URTI episodes were medically-confirmed. Symptom severity was recorded via self-reported daily Wisconsin Upper Respiratory Tract Infection Score 21. Blood and saliva samples were collected at days 0, 45 and 90 for measurements of innate immune parameters. Results Forty-nine participants completed the trial in each group. Supplementation was well-tolerated. A total of 45 URTIs were confirmed, 28 in the placebo group and 17 in the Wellmune group (odds ratio 0.55 (95% CI 0.24, 1.26); p=0.149). There was a strong trend for Wellmune to decrease the number of symptom days (p=0.067). Symptom severity was not significantly different between groups. Compared to the placebo group, lipopolysaccharide-stimulated blood from participants in the Wellmune group showed an increase in interferon-gamma concentration from baseline at day 45 (p=0.016) and smaller decreases in monokine induced by interferon-gamma concentration from baseline at days 45 and 90 (p=0.032 and 0.046). No difference was seen in serum or non-stimulated blood cytokines and chemokines or in salivary IgA. Conclusion Daily oral beta 1,3/1,6 glucan may protect against URTIs and reduce the duration of URTI symptoms once infected in older people. This may be linked to effects on innate immune function. Larger studies are needed to confirm the benefits of beta 1,3/1,6 glucan on URTIs in older people.
PDF
