On the importance of nonlinear modeling in computer performance prediction

Computers are nonlinear dynamical systems that exhibit complex and sometimes even chaotic behavior. The models used in the computer systems community, however, are linear. This paper is an exploration of that disconnect: when linear models are adequate for predicting computer performance and when they are not. Specifically, we build linear and nonlinear models of the processor load of an Intel i7-based computer as it executes a range of different programs. We then use those models to predict the processor loads forward in time and compare those forecasts to the true continuations of the time seriesComment: Appeared in "Proceedings of the 12th International Symposium on Intelligent Data Analysis

Evaluation of the Liverpool Drink Less Enjoy More intervention

In the UK it is an offence to knowingly sell alcohol to, or purchase alcohol for, a drunk person (Regulated under Section 141 and 142 of the Licensing Act 2003). However, until recent times public awareness, bar server compliance and police enforcement of this legislation has appeared to be low. Critically, UK nightlife environments are often characterised by high levels of intoxication and alcohol-related harms. Excessive alcohol use damages the public’s health, while managing nightlife drunkenness and associated problems such as anti-social behaviour and violence places huge demands on police, local authorities and health services. To reduce such harms an extensive range of policies and interventions have been implemented at local and national levels including high profile policing, changes to licensing laws and environmental measures to improve safety. Whilst there is some evidence to indicate that these measures may contain and manage alcohol-related harms, they do little to reduce levels of intoxication or address harmful and pervasive cultures of nightlife drunkenness. A study conducted in Liverpool in 2013 found that 84% of alcohol purchase attempts by pseudo-intoxicated actors in pubs, bars and nightclubs were successful (i.e. alcohol was sold to the actor; Hughes et al., 2014). Studies conducted elsewhere have suggested that reductions in the service of alcohol to drunks, and associated harms, in nightlife settings can be achieved through the implementation of multi-component interventions that incorporate community mobilisation, enforcement of the laws around the service of alcohol to drunks and responsible bar server training. Thus to address the sale of alcohol to drunks in the city’s nightlife, local partners developed and implemented the multi-component Say No To Drunks pilot intervention. The intervention aimed to: increase awareness of legislation preventing sales of alcohol to drunks; support bar staff compliance with the law; provide a strong deterrence to selling alcohol to drunks; and promote responsible drinking amongst nightlife users. Following an evaluation of Say No To Drunks, the intervention was further refined, broadened and implemented as a second phase in 2015 – rebranded to Drink Less Enjoy More. To inform the continued development of the intervention, the Centre for Public Health at Liverpool John Moores University was commissioned to evaluate the intervention, comparing the results to previous work

Violence-related ambulance call-outs in the North West of England: a cross-sectional analysis of nature, extent and relationships to temporal, celebratory and sporting events

OBJECTIVE: The aim of this study was to explore the potential of ambulance call-out data in understanding violence to inform about prevention activity. METHOD: This cross-sectional (2013–2015) study examined the nature, extent and characteristics of violence-related ambulance call-outs (n=15 687) across North West England and relationships with temporal, celebratory and sporting events. RESULTS: The majority of call-outs were for men, with a mean age of 33 years. Most call-outs were to deprived (64.4%) and urban (65.4%) areas and occurred at night (18:00–5:59; 75.2%). Three-quarters (77.3%) were recorded as assault/sexual assault and 22.7% stab/gunshot/penetrating trauma. Significant differences in call-out characteristics were identified between the two violence types. Generalised linear modelling found that call-outs significantly increased on weekends, New Year’s Eve and weekday bank holiday eves (except for stab/gunshot/penetrating trauma). No significant associations between all violence call-outs, the two violence categories and sporting or celebration events were identified. Two-thirds (66.1%) of the call-outs were transferred to another health service for further assessment and/or treatment. The odds of being transferred were significantly higher among men (adjusted OR (AOR) 1.5, 95%CI 1.4 to 1.6), those aged 13–24 years (AOR 1.2, 95%CI 1.0 to 1.4), call-outs for stab/gunshot/penetrating trauma (AOR 1.4, 95%CI 1.3 to 1.5) and call-outs on Fridays/Saturdays (AOR 1.1, 95%CI 1.0 to 1.2) and lower for call-outs on New Year’s Eve (AOR 0.6, 95%CI 0.4 to 0.9). CONCLUSION: Ambulance call-out data can provide a wealth of information to understand violence and subsequently inform about violence prevention and response activity. Ambulance services and staff could play a key role in preventing violence through sharing data and identifying and supporting victims

N-Acetylcysteine improves mitochondrial function and ameliorates behavioral deficits in the R6/1 mouse model of Huntington\u27s disease

Huntington\u27s disease (HD) is a neurodegenerative disorder, involving psychiatric, cognitive and motor symptoms, caused by a CAG-repeat expansion encoding an extended polyglutamine tract in the huntingtin protein. Oxidative stress and excitotoxicity have previously been implicated in the pathogenesis of HD. We hypothesized that N-acetylcysteine (NAC) may reduce both excitotoxicity and oxidative stress through its actions on glutamate reuptake and antioxidant capacity. The R6/1 transgenic mouse model of HD was used to investigate the effects of NAC on HD pathology. It was found that chronic NAC administration delayed the onset and progression of motor deficits in R6/1 mice, while having an antidepressant-like effect on both R6/1 and wild-type mice. A deficit in the astrocytic glutamate transporter protein, GLT-1, was found in R6/1 mice. However, this deficit was not ameliorated by NAC, implying that the therapeutic effect of NAC is not due to rescue of the GLT-1 deficit and associated glutamate-induced excitotoxicity. Assessment of mitochondrial function in the striatum and cortex revealed that R6/1 mice show reduced mitochondrial respiratory capacity specific to the striatum. This deficit was rescued by chronic treatment with NAC. There was a selective increase in markers of oxidative damage in mitochondria, which was rescued by NAC. In conclusion, NAC is able to delay the onset of motor deficits in the R6/1 model of Huntington\u27s disease and it may do so by ameliorating mitochondrial dysfunction. Thus, NAC shows promise as a potential therapeutic agent in HD. Furthermore, our data suggest that NAC may also have broader antidepressant efficacy

Covariant description of inelastic electron--deuteron scattering:predictions of the relativistic impulse approximation

Using the covariant spectator theory and the transversity formalism, the unpolarized, coincidence cross section for deuteron electrodisintegration, $d(e,e'p)n$, is studied. The relativistic kinematics are reviewed, and simple theoretical formulae for the relativistic impulse approximation (RIA) are derived and discussed. Numerical predictions for the scattering in the high $Q^2$ region obtained from the RIA and five other approximations are presented and compared. We conclude that measurements of the unpolarized coincidence cross section and the asymmetry $A_\phi$, to an accuracy that will distinguish between different theoretical models, is feasible over most of the wide kinematic range accessible at Jefferson Lab.Comment: 54 pages and 24 figure

Genome‐wide studies of von Willebrand factor propeptide identify loci contributing to variation in propeptide levels and von Willebrand factor clearance

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134219/1/jth13401-sup-0001-FigS1-S7.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134219/2/jth13401.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134219/3/jth13401_am.pd

Nitrogen in ruminant nutrition: a review of measurement techniques

Nitrogen (N) is a component of essential nutrients critical for the productivity of ruminants. If excreted in excess, N is also an important environmental pollutant contributing to acid deposition, eutrophication, human respiratory problems, and climate change. The complex microbial metabolic activity in the rumen and the impact on subsequent processes in the intestines and body tissues make the study of N metabolism in ruminants challenging compared to non-ruminants. Therefore, using accurate and precise measurement techniques is imperative for obtaining reliable experimental results on N utilization by ruminants and evaluating the environmental impacts of N emission mitigation techniques. Changeover design experiments are as suitable as continuous ones for studying protein metabolism in ruminant animals, except when changes in body weight or carryover effects due to treatment are expected. Adaptation following a dietary change should be allowed for at least 2 (preferably 3) weeks, and extended adaptation periods may be required if body pools can temporarily supply the nutrients studied. Dietary protein degradability in the rumen and intestines are feed characteristics determining the primary amino acids available to the host animal. They can be estimated using in situ, in vitro, or in vivo techniques with each having inherent advantages and disadvantages. There is still a need for accurate, precise, and inexpensive laboratory assays for feed protein availability. Techniques used for direct determination of rumen microbial protein synthesis are laborious, expensive, and data variability can be unacceptably large; indirect approaches have not shown the level of accuracy required for widespread adoption. Techniques for studying postruminal digestion and absorption of nitrogenous compounds, urea recycling, and mammary amino acid metabolism are also laborious, expensive (especially the methods that utilize isotopes), and results can be variable, especially the methods based on measurements of digesta or blood flow. Volatile loss of N from feces and urine can be substantial during collection, processing, and analysis of excreta, compromising the accuracy of measurements of total tract N digestion and body N balance. In studying ruminant N metabolism, nutritionists should consider the longer-term fate of manure N as well. Various techniques used to determine the effects of animal nutrition on total N, ammonia- or nitrous oxide-emitting potentials, as well as plant fertilizer value, of manure are available. Overall, over 150 years of animal nutrition research have developed methods to study ruminant N metabolism, but many of them are laborious and impractical for application on a large number of animals. The increasing environmental concerns associated with livestock production systems necessitate a more accurate and reliable methods to determine manure N emissions in the context of feed composition and ruminant N metabolism

Galaxy Pairs in the Sloan Digital Sky Survey - II: The Effect of Environment on Interactions

We use a sample of close galaxy pairs selected from the Sloan Digital Sky Survey Data Release 4 (SDSS DR4) to investigate in what environments galaxy mergers occur and how the results of these mergers depend on differences in local galaxy density. The galaxies are quantified morphologically using two-dimensional bulge-plus-disk decompositions and compared to a control sample matched in stellar mass, redshift and local projected density. Lower density environments have fractionally more galaxy pairs with small projected separations (r_p) and relative velocities (Delta v), but even high density environments contain significant populations of pairs with parameters that should be conducive to interactions. Metrics of asymmetry and colour are used to identify merger activity and triggered star formation. The location of star formation is inferred by distinguishing bulge and disk colours and calculating bulge fractions from the SDSS images. Galaxies in the lowest density environments show the largest changes in star formation rate, asymmetry and bulge-total fractions at small separations, accompanied by bluer bulge colours. At the highest local densities, the only galaxy property to show an enhancement in the closest pairs is asymmetry. We interpret these results as evidence that whilst interactions (leading to tidal distortions) occur at all densities, triggered star formation is seen only in low-to-intermediate density environments. We suggest that this is likely due to the typically higher gas fractions of galaxies in low density environments. Finally, by cross-correlating our sample of galaxy pairs with a cluster catalogue, we investigate the dependence of interactions on clustercentric distance. It is found that for close pairs the fraction of asymmetric galaxies is highest in the cluster centres.Comment: Accepted by MNRAS, 15 page