Energy-efficiency evaluation of Intel KNL for HPC workloads

Energy consumption is increasingly becoming a limiting factor to the design of faster large-scale parallel systems, and development of energy-efficient and energy-aware applications is today a relevant issue for HPC code-developer communities. In this work we focus on energy performance of the Knights Landing (KNL) Xeon Phi, the latest many-core architecture processor introduced by Intel into the HPC market. We take into account the 64-core Xeon Phi 7230, and analyze its energy performance using both the on-chip MCDRAM and the regular DDR4 system memory as main storage for the application data-domain. As a benchmark application we use a Lattice Boltzmann code heavily optimized for this architecture and implemented using different memory data layouts to store its lattice. We assessthen the energy consumption using different memory data-layouts, kind of memory (DDR4 or MCDRAM) and number of threads per core

Evolution of a double-front Rayleigh-Taylor system using a GPU-based high resolution thermal Lattice-Boltzmann model

We study the turbulent evolution originated from a system subjected to a Rayleigh-Taylor instability with a double density at high resolution in a 2 dimensional geometry using a highly optimized thermal Lattice Boltzmann code for GPUs. The novelty of our investigation stems from the initial condition, given by the superposition of three layers with three different densities, leading to the development of two Rayleigh-Taylor fronts that expand upward and downward and collide in the middle of the cell. By using high resolution numerical data we highlight the effects induced by the collision of the two turbulent fronts in the long time asymptotic regime. We also provide details on the optimized Lattice-Boltzmann code that we have run on a cluster of GPU

Herbal highs: review on psychoactive effects and neuropharmacology

Background: A new trend among users of new psychoactive substances’ the consumption of “herbal highs”: plant parts containing psychoactive substances. Most of the substances extracted from herbs, in old centuries were at the centre of religious ceremonies of ancient civilizations. Currently, these herbal products are mainly sold by internet web sites and easily obtained since some of them have no legal restriction. Objective: We reviewed psychoactive effects and neuropharmacology of the most used “herbal highs” with characterized active principles, with studies reporting mechanisms of action, pharmacological and subjective effects, eventual secondary effects including intoxications and/or fatalities Method: The PubMed database was searched using the following key.words: herbal highs, Argyreia nervosa, Ipomoea violacea and Rivea corymbosa; Catha edulis; Datura stramonium; Piper methysticum; Mitragyna speciosa. Results: Psychoactive plants here reviewed have been known and used from ancient times, even if for some of them limited information still exist regarding subjective and neuropharmacological effects and consequent eventual toxicity when plants are used alone or in combination with “classical” drugs of abuse. Conclusion: Some “herbal highs” should be classified as harmful drugs since chronic administration has been linked with addiction and cognitive impairment; for some others taking into consideration only the recent trends of abuse, studies investigating these aspects are lacking

FER: A Benchmark for the Roofline Analysis of FPGA Based HPC Accelerators

Nowadays, the use of hardware accelerators to boost the performance of HPC applications is a consolidated practice, and among others, GPUs are by far the most widespread. More recently, some data centers have successfully deployed also FPGA accelerated systems, especially to boost machine learning inference algorithms. Given the growing use of machine learning methods in various computational fields, and the increasing interest towards reconfigurable architectures, we may expect that in the near future FPGA based accelerators will be more common in HPC systems, and that they could be exploited also to accelerate general purpose HPC workloads. In view of this, tools able to benchmark FPGAs in the context of HPC are necessary for code developers to estimate the performance of applications, as well as for computer architects to model that of systems at scale. To fulfill these needs, we have developed FER (FPGA Empirical Roofline), a benchmarking tool able to empirically measure the computing performance of FPGA based accelerators, as well as the bandwidth of their on-chip and off-chip memories. FER measurements enable to draw Roofline plots for FPGAs, allowing for performance comparisons with other processors, such as CPUs and GPUs, and to estimate at the same time the performance upper-bounds that applications could achieve on a target device. In this paper we describe the theoretical model on which FER relies, its implementation details, and the results measured on Xilinx Alveo accelerator cards

Prevalence of somatisation as a determinant of burnout amongst staff working in drug and alcohol services

Purpose: This study explored the prevalence of somatisation as a determinant of burnout amongst drug and alcohol staff in the UK. Design/methodology/approach: The study employed a cross-sectional design utilising a self-completion online questionnaire. Data was collected from substance misuse workers across England and Wales. 165 responses were eligible for analysis, yielding a response rate of 5%. Burnout and somatization were measured with Maslach’s Burnout Inventory and the Physical Symptoms Inventory. Findings: The prevalence of somatic symptoms was relatively low in the sample studied. The reported levels of burnout were moderate. Personal accomplishment remained high in the sample. There was a strong association between burnout and incidence of stress related somatic symptoms, with higher levels of burnout correlating with multiple symptoms. Research limitations/implications: It was not possible to determine the extent of non-response bias, as at the time of the study there was no information available relating to the characteristics of drug and alcohol staff in the selected services. Therefore, as the response rate was very low (5%) it was recognised that non-response bias might have affected the findings, in such way that non-respondents may have differed in their experiences of work stress, satisfaction, burnout and health outcomes. Practical implications: Despite the limitations, the study provided practical information relating to burnout vulnerability and associated physical symptoms in this specific occupational group. These findings can support employers to address staff wellbeing with a view to prevent burnout and reduce existing levels of burnout and related somatic symptoms, and improve job performance, job satisfaction, and staff retention through making appropriate adjustments, such as developing staff-wellbeing programmes. These adjustments could potentially contribute to improvement in substance misuse practice, through maintenance of healthy and satisfied workforce. Social implications: Originality/value: There is very few studies looking at burnout in drug and alcohol staff. This study is also novel in a way that it reveals correlations between a variety of specific stress related physical symptoms and the three components of burnout

The “Eyeballing” technique : an emerging and alerting trend of alcohol misuse

Alternative methods of alcohol consumption have recently emerged among adolescents and young adults, including the alcohol “eyeballing”, which consist in the direct pouring of alcoholic substances on the ocular surface epithelium. In a context of drug and behavioural addictions change, “eyeballing” can be seen as one of the latest and potentially highly risky new trends. We aimed to analyze the existing medical literature as well as online material on this emerging trend of alcohol misusePeer reviewedFinal Published versio

Recreational Drug Misuse and Its Potential Contribution to Male Fertility Levels’ Decline: A Narrative Review

Recreational drug intake may be associated with a range of medical untoward consequences, including male infertility. However, as the related evidence is still limited, the main outcome of this review is to provide a better understanding of the existence of any association between recreational drug misuse and male fertility levels’ decline. Whilst searching the MEDLINE/PubMed, a comprehensive overview of the literature regarding male infertility and substances of abuse (e.g., phytocannabinoids, opiates/opioids, stimulants, ‘herbal highs’, psychedelics, and ‘novel psychoactive substances) was here undertaken. Due to the paucity of robust, high-quality, empirical, human studies, a narrative strategy was here preferred over a systematic approach. Relevant data are qualitatively analyzed and presented in a table. Although most available evidence is in support of a detrimental role of cannabis on human spermatogenesis, a few remaining studies failed to document any effect of this drug on seminal quality, and it is not clear to which extent this drug impacts fertility rates/time to pregnancy. The current understanding of the impact of opiate-, cocaine- and amphetamine/stimulant-misuse on human reproduction is widely unknown, and most studies dealing with this matter represent only an extrapolation of data derived from specific clinical circumstances. Although the message of ‘no smoking, no alcohol and no street drugs’ should always be offered as good health advice to all patients seeking medical help for fertility issues, robust scientific clinical evidence in support of a direct detrimental impact of recreational drugs on spermatogenesis is scant to date

Build up of yield stress fluids via chaotic emulsification

Stabilised dense emulsions display a rich phenomenology connecting microstructure and rheology. In this work, we study how an emulsion with a finite yield stress can be built via large-scale stirring. By gradually increasing the volume fraction of the dispersed minority phase, under the constant action of a stirring force, we are able to achieve a volume fraction close to (Formula presented.). Despite the fact that our system is highly concentrated and not yet turbulent we observe a droplet size distribution consistent with the (Formula presented.) scaling, often associated with inertial range droplets breakup. We report that the polydispersity of droplet sizes correlates with the dynamics of the emulsion formation process. Additionally, we quantify the visco-elastic properties of the dense emulsion finally obtained and we demonstrate the presence of a finite yield stress. The approach reported can pave the way to a quantitative understanding of the complex interplay between the dynamics of mesoscale constituents and the large-scale flow properties of yield stress fluids