How to Modify LAMMPS: From the Prospective of a Particle Method Researcher

LAMMPS is a powerful simulator originally developed for molecular dynamics that, today, also accounts for other particle-based algorithms such as DEM, SPH, or Peridynamics. The versatility of this software is further enhanced by the fact that it is open-source and modifiable by users. This property suits particularly well Discrete Multiphysics and hybrid models that combine multiple particle methods in the same simulation. Modifying LAMMPS can be challenging for researchers with little coding experience. The available material explaining how to modify LAMMPS is either too basic or too advanced for the average researcher. In this work, we provide several examples, with increasing level of complexity, suitable for researchers and practitioners in physics and engineering, who are familiar with coding without been experts. For each feature, step by step instructions for implementing them in LAMMPS are shown to allow researchers to easily follow the procedure and compile a new version of the code. The aim is to fill a gap in the literature with particular reference to the scientific community that uses particle methods for (discrete) multiphysics

How to modify LAMMPS: from the prospective of a particle method researcher

LAMMPS is a powerful simulator originally developed for molecular dynamics that, today, also accounts for other particle-based algorithms such as DEM, SPH, or Peridynamics. The versatility of this software is further enhanced by the fact that it is open-source and modifiable by users. This property suits particularly well Discrete Multiphysics and hybrid models that combine multiple particle methods in the same simulation. Modifying LAMMPS can be challenging for researchers with little coding experience. The available material explaining how to modify LAMMPS is either too basic or too advanced for the average researcher. In this work, we provide several examples, with increasing level of complexity, suitable for researchers and practitioners in physics and engineering, who are familiar with coding without been experts. For each feature, step by step instructions for implementing them in LAMMPS are shown to allow researchers to easily follow the procedure and compile a new version of the code. The aim is to fill a gap in the literature with particular reference to the scientific community that uses particle methods for (discrete) multiphysics

Volcanic and geochemical evolution of the Teno massif, Tenerife, Canary Islands: some repercussions of giant landslides on ocean island magmatism

Large-scale, catastrophic mass wasting is a major process contributing to the dismantling of oceanic intraplate volcanoes. Recent studies, however, have highlighted a possible feedback relationship between flank collapse, or incipient instability, and subsequent episodes of structural rearrangement and/or renewed volcano growth. The Teno massif, located in northwestern Tenerife (Canary Islands), is a deeply eroded Miocene shield volcano that was built in four major eruptive phases punctuated by two lateral collapses, each removing >20–25 km3 of the volcano's north flank. In this paper, we use detailed field observations and petrological and geochemical data to evaluate possible links between large-scale landslides and subsequent volcanism/magmatism during Teno's evolution. Inspection of key stratigraphic sequences reveals that steep angular unconformities, relics of paleolandslide scars, are marked by polymict breccias. Near their base, these deposits typically include abundant juvenile pyroclastic material, otherwise scarce in the region. While some of Teno's most evolved, low-density magmas were produced just before flank collapses, early postlandslide lava sequences are characterized by anomalously high proportions of dense ankaramite flows, extremely rich in clinopyroxene and olivine crystals. A detailed sampling profile shows transitions from low-Mg # lavas relatively rich in SiO2 to lavas with low silica content and comparatively high Mg # after both landslides. Long-term variations in Zr/Nb, normative nepheline, and La/Lu are coupled but do not show a systematic correlation with stratigraphic boundaries. We propose that whereas loading of the growing precollapse volcano promoted magma stagnation and differentiation, the successive giant landslides modified the shallow volcano-tectonic stress field at Teno, resulting in widespread pyroclastic eruptions and shallow magma reservoir drainage. This rapid unloading of several tens of km3 of near-surface rocks appears to have upset magma differentiation processes, while facilitating the remobilization and tapping of denser ankaramite magmas that were stored in the uppermost mantle. Degrees of mantle melting coincidently reached a maximum in the short time interval between the two landslides and declined shortly after, probably reflecting intrinsic plume processes rather than a collapse-induced influence on mantle melting. Our study of Teno volcano bears implications for other oceanic volcanoes where short-term compositional variations may also directly relate to major flank collapse events

Changes in Alcohol Consumption after 1 Year of the COVID-19 Pandemic: A Cross-Sectional Study in a Region of France

Background: There is conflicting evidence on how the COVID-19 pandemic changed patterns of alcohol consumption. While some studies have suggested that alcohol consumption decreased at the beginning of the pandemic, there are limited data for a longer period. The objective of this study was to investigate changes in alcohol consumption 1 year after the onset of the COVID-19 pandemic in France, and to identify vulnerable subgroups in a French adult population. Methods: This was a single-center, cross-sectional, descriptive study. Self-reported changes in alcohol consumption were collected from 2491 respondents in a survey carried out in western Brittany from 18 January to 9 March 2021. Results: Of respondents, 27.64% reported that they had increased their alcohol consumption, 14.7% had decreased, 3.94% had ceased, and 53.72% reported no change in their alcohol consumption. Increased alcohol use was associated with male gender, age 26 to 44 years, living with a family, not being a health professional, having had a physical or psychological health problem during lockdowns, smoking tobacco, and using cannabis. Reduced alcohol use or cessation was associated with male gender, age 18 to 25 years, living in Brest, living alone, and using cannabis. Conclusions: Our study suggests that during the COVID-19 pandemic, a significant number of people increased their alcohol consumption in France, even outside lockdowns. These results should encourage health professionals and public authorities to implement more specific prevention measures to limit the risks associated with alcohol consumption

Experiments to quantity aerosol transport from sprinkler irrigation and to assess in field sampling methods

International audienc

Experiments to quantity aerosol transport from sprinkler irrigation and to assess in field sampling methods

International audienc

Impact of alcohol marketing on drinkers with Alcohol use disorders seeking treatment: a mixed-method study protocol

International audienceBackgroundThe marketing of alcohol influences patterns of alcohol consumption. Existing studies have focused, for the most part, on adolescents and the links between exposure to marketing and alcohol initiation. In France, the Evin law, a French exception, was set up in 1991 with the aim of regulating this exposure to marketing, but since 2009 it has been severely compromised. Alcohol consumption causes severe damage, which may be seenfrom 1 standard unit per day and mostly among adults who are regular users of alcohol. In this at-risk population, studies analysing the impact of marketing are sparse.The specific objectives include (i) the evaluation of the perception of alcohol marketing by patients with an AUD (ii) gaining understanding of the links between alcohol marketing and patients with AUD behaviours (iii) the development of alcohol demarketing strategy in patients receiving AUD coaching.MethodsOur main objective isto evaluate the impact of marketing on a population with an AUD. The methodology was in 4 steps: step 1 is a pre-test (N = 100) selecting type of alcohol consumed and type of marketing stimuli identified by patients aged 18 + with an AUD. Step 2 is a qualitative study (N = 20), with in-depth interview, to understand links between alcohol marketing and patients with AUD behaviours. Step 3 is a quantitative study(N = 600) to confirm these links and the impact of alcohol marketing on patients with AUD behaviours. Step 4 is an interventional step, including and testing the impact of demarketing intervention on patients with AUD while using the results of the three first steps (N = 120).DiscussionThis study will contribute to a better definition of the impact of alcohol marketing on patients with AUD and will enable identification of the determinants of this impact. These data will inform the development of interventions that take into account demarketingstrategies on patients under AUD management

Alcohol use disorders, beverage preferences and the influence of alcohol marketing: a preliminary study

International audienceBackground Alcohol Use Disorders (AUD) are among the most prevalent mental disorders in the world. They are the leading risk factor for premature mortality and disability among 15 to 49-year-olds. Links between alcohol marketing and patterns of alcohol consumption are well defined in adolescents but there is few data on the impact of alcohol marketing on a population of drinkers with an AUD and seeking treatment. This study was designed in collaboration among researchers specialising in addictive disorders, in social marketing and primary care. Methods This was a monocentric, cross-sectional, descriptive study. The main objective of this study was to define the type of marketing identified by drinkers with an AUD who were seeking treatment and their beverage preferences. Drinkers aged 18+ with an AUD and seeking treatment were included. A descriptive analysis and a logistic regression were carried out . Results N = 91 patients were included, 73.6% were male, the average age was 46.2 years. 72% said they were not influenced by alcohol marketing, but 76% recalled an alcohol advertisement in the last 6 months. The most frequently reported beverage preferences were wine (39.6%), standard beers (29.6%), spirits (27.5%) and strong beers (16.5%). Conclusions Patients with AUD, defined as vulnerable, reported exposure to alcohol marketing but did not seem to identify it consciously. Marketing influences differed according to beverage preferences. These results need to be confirmed by a larger study

Feed restriction affects protein and microRNA levels in dairy cows' milk

International audienceThe aim of this study was to observe the effect of feed restriction (FR) on milk concentrations of major proteins and microRNA in order to identify potential biomarkers of negative energy balance in cows. We hypothesized that the effects of FR on mammary gland metabolism are reflected in milk and its different fractions. Two FR trials were conducted at mid lactation to induce negative energy balance: a short duration and high intensity one (SH) and a long duration and moderate intensity one (LM). The SH experiment involved 8 Holstein cows. The LM experiment involved 19 Holstein cows either in control (n=9) or restriction conditions (n=10). FR lasted 6 and 29 days with a dry matter intake reduced by 64 and 20% of ad libitum intake, and induced a negative energy balance of-42 and-21 MJ/d, respectively for SH and LM experiments. Milk was sampled before, during (3 times for LM) and after the restriction periods. MicroRNA, extracted from whole milk, fat globules, milk isolated mammary epithelial cells and extracellular vesicles were sequenced and protein concentrations analyzed using LC-MS. Concentration of several major proteins decreased during FR: αS2-casein (LM and SH), αS1-casein (SH), κ-casein (LM), α-lactalbumin (LM), β-lactoglobulin (LM). Among 2896 microRNA detected in milk, the abundance of 159 microRNA was affected by FR, mostly in extracellular vesicles (n=83) and whole milk (n=85), few in fat globules (n=6), but none in mammary epithelial cells. Among these 159 microRNA, 15 varied in two compartments. These experiments showed that FR affects the abundance of proteins and microRNA in milk. It may reflect modifications of mammary gland metabolism. These results will be further explored by proteomic analysis and by RT-qPCR on more samples. These preliminary results are promising in the search for non-invasive biomarkers of negative energy balance in milk