Variaciones morfologicas del rotifero Keratella americana (Carlin, 1943) de una laguna de inundacion del rio Orinoco, Venezuela

L'analyse dy rapport de la longueur de l'épine postérieure à celle de la lorica a montré que l'épine postérieure est significativement plus courte pendantles basses eaux que pendant la crue. Compte-tenu des facteurs habituellement associé au polymorphisme de #Brachionus et #Keratella, on émet l'hypothèse que la variation observée est liée à la disponibilité de la nourriture. Une longue épine postérieure serait un avantage en période de moindre nourriture (période de hautes eaux) tandis qu'à l'étiage une courte épine serait profitable quand la disponibilité des proies augmente. Il a aussi été observé que de faibles variations d'abondance d' #Asplanchna, prédateur du rotifère, affectent la densité de #K. americana, mais sans effet notable sur la longueur de l'épine. En se fondant sur la nomenclature existante existante pour #K. cochlearis, nous proposons la désignation de #K. americana Carlin, 1943 (f. #hispida nov. f.) comme super-espèce incluant lees formes #typica (longue épine postérieure), f. #tecta (sans épine postérieure) et, intermédiaires entre ces extrêmes, et en ordre de longueur d'épine décroissante, les formes #micracantha et #tuberculata$. (Résumé d'auteur

Droplet actuation induced by coalescence: experimental evidences and phenomenological modeling

This paper considers the interaction between two droplets placed on a substrate in immediate vicinity. We show here that when the two droplets are of different fluids and especially when one of the droplet is highly volatile, a wealth of fascinating phenomena can be observed. In particular, the interaction may result in the actuation of the droplet system, i.e. its displacement over a finite length. In order to control this displacement, we consider droplets confined on a hydrophilic stripe created by plasma-treating a PDMS substrate. This controlled actuation opens up unexplored opportunities in the field of microfluidics. In order to explain the observed actuation phenomenon, we propose a simple phenomenological model based on Newton's second law and a simple balance between the driving force arising from surface energy gradients and the viscous resistive force. This simple model is able to reproduce qualitatively and quantitatively the observed droplet dynamics

Associations between perceived neighborhood environment and cognitive function among middle-aged and older women and men: Hispanic Community Health Study/Study of Latinos Sociocultural Ancillary Study

Purpose: To examine cross-sectional associations between perceived neighborhood environment and cognitive function among middle-aged and older Hispanic/Latino women and men. Methods: Data from the Hispanic Community Health Study/Study of Latinos (2008–2011) and its Sociocultural Ancillary Study (2009–2010) were used. Participants were Hispanic/Latino women (n = 1812) and men (n = 1034) aged 45–74 years. Survey-weighted linear regression models were used to examine associations between self-reported perceived neighborhood environment (i.e., neighborhood social cohesion and problems categorized as quintiles, and neighborhood safety from crime categorized as low, medium, or high) with cognitive function (i.e., global cognition, verbal learning, memory, verbal fluency, and processing speed scores) in women and men. Final model adjusted for age, Hispanic/Latino background, language, field site, household income, education, years lived in neighborhood, and depressive symptoms. Results: Women in the lowest quintile of perceived neighborhood problems (vs. highest quintile) had higher global cognition (β 0.48, 95% CI 0.03, 0.94, p trend 0.229) and memory scores (0.60, 95% CI 0.11, 1.09, p trend: 0.060). Women in the highest quintile of perceived neighborhood social cohesion (vs. lowest quintile) had lower global cognition (β − 0.56, 95% CI − 1.02, − 0.09, p trend 0.004), verbal learning (B − 1.01, 95% CI − 2.00, − 0.03, p trend 0.015), verbal fluency (B − 2.00, 95% CI − 3.83, − 0.16, p trend 0.006), and processing speed (B − 2.11, 95% CI − 3.87, − 0.36, p trend 0.009). There was no association between perceived neighborhood safety from crime and cognition among women, or between any perceived neighborhood environment measure and cognition among men. Conclusions: Middle-aged and older Hispanic/Latina women living in neighborhoods with the lowest perceived problems had higher global cognition and memory. Women living in neighborhoods with the highest perceived social cohesion had lower global cognition, verbal learning, verbal fluency, and processing speed

Energy management systems and tertiary regulation in hierarchical control architectures for islanded micro-grids

Preprin

Local mean-field study of capillary condensation in silica aerogels

We apply local mean-field (i.e. density functional) theory to a lattice model of a fluid in contact with a dilute, disordered gel network. The gel structure is described by a diffusion-limited cluster aggregation model. We focus on the influence of porosity on both the hysteretic and the equilibrium behavior of the fluid as one varies the chemical potential at low temperature. We show that the shape of the hysteresis loop changes from smooth to rectangular as the porosity increases and that this change is associated to disorder-induced out-of-equilibrium phase transitions that differ on adsorption and on desorption. Our results provide insight in the behavior of $^4$He in silica aerogels.Comment: 19 figure

Associations between physical activity, sedentary behaviour and left ventricular structure and function from the Echocardiographic Study of Latinos (ECHO-SOL)

Objective The cross-sectional association between accelerometer-measured physical activity (PA), sedentary behaviour (SB) and cardiac structure and function is less well described. This study's primary aim was to compare echocardiographic measures of cardiac structure and function with accelerometer measured PA and SB. Methods Participants included 1206 self-identified Hispanic/Latino men and women, age 45-74 years, from the Echocardiographic Study of Latinos. Standard echocardiographic measures included M-mode, two-dimensional, spectral, tissue Doppler and myocardial strain. Participants wore an Actical accelerometer at the hip for 1 week. Results The mean±SE age for the cohort was 56±0.4 years, 57% were women. Average moderate to vigorous PA (MVPA) was 21±1.1 min/day, light PA was 217±4.2 min/day and SB was 737±8.1 min/day. Both higher levels of light PA and MVPA (min/day) were associated with lower left ventricular (LV) mass index (LVMI)/end-diastolic volume and a lower E/e′ ratio. Higher levels of MVPA (min/day) were associated with better right ventricular systolic function. Higher levels of SB were associated with increased LVMI. In a multivariable linear regression model adjusted for demographics and cardiovascular disease modifiable factors, every 10 additional min/day of light PA was associated with a 0.03 mL/m 2 increase in left atrial volume index (LAVI) (p<0.01) and a 0.004 cm increase in tricuspid annular plane systolic excursion (p<0.01); every 10 additional min/day of MVPA was associated with a 0.18 mL/m 2 increase in LAVI (p<0.01) and a 0.24% improvement in global circumferential strain (p<0.01). Conclusions Our findings highlight the potential positive association between the MVPA and light PA on cardiac structure and function

Solar Wind Turbulence and the Role of Ion Instabilities

International audienc

TRY plant trait database – enhanced coverage and open access

Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives