497 research outputs found
The seasonal relationship between intraseasonal tropical variability and ENSO in CMIP5
The El Niño–Southern Oscillation (ENSO) is tightly linked to the
intraseasonal tropical variability (ITV) that contributes to energise the
deterministic ocean dynamics during the development of El Niño. Here, the
relationship between ITV and ENSO is assessed based on models from the
Coupled Model Intercomparison Project (CMIP) phase 5 (CMIP5) taking into
account the so-called diversity of ENSO, that is, the existence of two types
of events (central Pacific versus eastern Pacific El Niño). As a first
step, the models' skill in simulating ENSO diversity is assessed. The
characteristics of the ITV are then documented revealing a large dispersion
within an ensemble of 16 models. A total of 11 models exhibit some skill in
simulating the key aspects of the ITV for ENSO: the total variance along the
Equator, the seasonal cycle and the characteristics of the propagation along
the Equator of the Madden–Julian oscillation (MJO) and the convectively
coupled equatorial Rossby (ER) waves. Five models that account realistically
for both the two types of El Niño events and ITV characteristics are used
for the further analysis of seasonal ITV ∕ ENSO relationship. The results
indicate a large dispersion among the models and an overall limited skill in
accounting for the observed seasonal ITV ∕ ENSO relationship.
Implications of our results are discussed in light of recent studies on the
forcing mechanism of ENSO diversity
Environmental Drivers of Mesophotic Echinoderm Assemblages of the Southeastern Pacific Ocean
Mesophotic ecosystems (50–400 m depth) of the southeastern Pacific have rarely been studied because of the logistical challenges in sampling across this remote zone. This study assessed how oxygen concentrations and other environmental predictors explain variation in echinoderm assemblages at these mesophotic systems, where this group is among the predominant fauna. We compiled data on echinoderm taxa at 91 sampling stations, from historical and recent surveys (between 1950 and 2019), covering a longitudinal gradient of approximately 3,700 km along with the Nazca, Salas y Gómez, and Juan Fernández ridges. Uni- and multivariate model-based tools were applied to analyze the patterns of benthic fauna in relation to environmental factors. Our results indicate a significant positive relationship between echinoderm species richness and depth, oxygen, and salinity. Changes in echinoderm community composition were significantly explained by oxygen, longitude, and chlorophyll-a. We observed notable species turnovers at ∼101 and ∼86°W, where assemblages tend to be more variable across stations. This turnover possibly reflects the effects of physical barriers to dispersion (e.g., currents) and habitat changes. Echinoderm assemblages observed around Easter and Desventuradas Islands presented a high occurrence of potentially endemic taxa and distinct species assemblages. This study is the first to assess the structure of mesophotic echinoderm assemblages of the southeastern Pacific Ocean along a large spatial scale. The information reported here could help design appropriate management tools for the vast, recently created, marine protected areas in the southeastern Pacific
Assessment of physical, environmental, and cardiac strain in 43 operators (wearing protective equipment) conducting clean-up of heavy oil products
Background. The aim of the study was to organise an assessment of the physical strains and environmental
exposure to hydrocarbon derivatives in persons involved in shoreline clean-up of heavy oil products, in
order to investigate the dangers of oil spill clean-up.
Material and methods. Forty-three healthy volunteers wearing protective equipment cleaning up an
artificial shoreline underwent cardiac strain measurements, as well as
a study of thermal stress (approximate WBGT index, water loss, measurement of internal body temperature
before and after physical activity). A subjective assessment of perceived exertion was correlated to articular
strain indicators recorded for the weight of loads lifted, movement frequency, and the range of movement.
Environmental exposure was determined by using portable hydrocarbon detectors.
Results. For adult subjects in good physical condition, in neutral temperatures, oil spill clean-up is considered
non-arduous. However, in sedentary, stressed subjects exposed to difficult climatic conditions, cleanup
can be considered hard to extremely hard. In terms of environmental exposure, slight traces of toluene
appeared once out of a total of 18 analysed samples.
Conclusions. The sample studied was subject to physical articular strains and presented variable cardiac
strain; environmental exposure was, on the other hand, slight when involving cleaning up heavy petroleum
products. The subjects liable to carry out this activity are more tolerant to the efforts required when they
are healthy, fit, young adults, in the non-arduous thermal conditions recorded in this study
The effect of flares on total solar irradiance
Flares are powerful energy releases occurring in stellar atmospheres. Solar
flares, the most intense energy bursts in the solar system, are however hardly
noticeable in the total solar luminosity. Consequently, the total amount of
energy they radiate 1) remains largely unknown and 2) has been overlooked as a
potential contributor to variations in the Total Solar Irradiance (TSI), i.e.
the total solar flux received at Earth. Here, we report on the detection of the
flare signal in the TSI even for moderate flares. We find that the total energy
radiated by flares exceeds the soft X-ray emission by two orders of magnitude,
with an important contribution in the visible domain. These results have
implications for the physics of flares and the variability of our star.Comment: accepted in Nature Physic
Self-regulation: differences by year and area in college students
Neste estudo procura-se analisar a existência de diferenças nas estratégias auto-regulatórias de alunos universitários em áreas de formação distintas. Participaram 518 alunos de três níveis (inicial, intermédio e final) das áreas de ciências e humanidades. Aplicou-se a escala “CHE – Comportamentos e hábitos de estudo e aprendizagem”, que avalia cinco dimensões: estratégias cognitivas de transformação e manipulação da informação, organização e planeamento de rotinas, gestão e monitorização, aquisição e selecção da informação, e reforço motivacional. Verificou-se uma maior utilização das estratégias cognitivas e metacognitivas de gestão e monitorização apesar dos resultados não indicarem diferenças substantivas entre os alunos diferenciados por nível e área. Os resultados podem indicar estabilidade nos comportamentos ou limitações no tipo de instrumento e amostra utilizada. O estudo de mudanças nestas estratégias deverá ser conduzido com recurso a delineamentos longitudinais. O impacto da estabilidade deverá ser ponderado na elaboração de projectos de intervenção.In this study we seek to analyze the existence of differences in self-regulating strategies of university students in distinct graduation areas. 518 students of three levels (initial, intermediate and final) of science and humanities fields participated. We used the scale “Behavior and study skill”, which evaluates five dimensions: cognitive strategies of transformation and manipulation of information, organization and planning of routines, management and monitoring, information acquisition and selection, and motivational reinforcement. A higher use of cognitive and metacognitive strategies of management and monitoring was noted although the results do not indicate major differences between students in different levels and graduation areas. The results can indicate stability in the behaviors or limitations in the type of instrument and in the sample used. The study of changes in these strategies must be carried out having in mind longitudinal outlines. The impact of the stability should be taken into account while elaborating intervention projects.(undefined
Facial expressions depicting compassionate and critical emotions: the development and validation of a new emotional face stimulus set
Attachment with altruistic others requires the ability to appropriately process affiliative and kind facial cues. Yet there is no stimulus set available to investigate such processes. Here, we developed a stimulus set depicting compassionate and critical facial expressions, and validated its effectiveness using well-established visual-probe methodology. In Study 1, 62 participants rated photographs of actors displaying compassionate/kind and critical faces on strength of emotion type. This produced a new stimulus set based on N = 31 actors, whose facial expressions were reliably distinguished as compassionate, critical and neutral. In Study 2, 70 participants completed a visual-probe task measuring attentional orientation to critical and compassionate/kind faces. This revealed that participants lower in self-criticism demonstrated enhanced attention to compassionate/kind faces whereas those higher in self-criticism showed no bias. To sum, the new stimulus set produced interpretable findings using visual-probe methodology and is the first to include higher order, complex positive affect displays
Knowledge-based energy functions for computational studies of proteins
This chapter discusses theoretical framework and methods for developing
knowledge-based potential functions essential for protein structure prediction,
protein-protein interaction, and protein sequence design. We discuss in some
details about the Miyazawa-Jernigan contact statistical potential,
distance-dependent statistical potentials, as well as geometric statistical
potentials. We also describe a geometric model for developing both linear and
non-linear potential functions by optimization. Applications of knowledge-based
potential functions in protein-decoy discrimination, in protein-protein
interactions, and in protein design are then described. Several issues of
knowledge-based potential functions are finally discussed.Comment: 57 pages, 6 figures. To be published in a book by Springe
TMG 1 (2014): Pandemic Disease in the Medieval World: Rethinking the Black Death, ed. Monica Green
The plague organism (Yersinia pestis) killed an estimated 40% to 60% of all people when it spread rapidly through the Middle East, North Africa, and Europe in the fourteenth century: an event known as the Black Death. Previous research has shown, especially for Western Europe, how population losses then led to structural economic, political, and social changes. But why and how did the pandemic happen in the first place? When and where did it begin? How was it sustained? What was its full geographic extent? And when did it really end? Pandemic Disease in the Medieval World is the first book to synthesize the new evidence and research methods that are providing fresh answers to these crucial questions. It was only in 2011, thanks to ancient DNA recovered from remains unearthed in London’s East Smithfield cemetery, that the full genome of the plague pathogen was identified. This single-celled organism probably originated 3000-4000 years ago and has caused three pandemics in recorded history: the Justinianic (or First) Plague Pandemic, around 541-750; the Black Death (Second Plague Pandemic), conventionally dated to the 1340s; and the Third Plague Pandemic, usually dated from around 1894 to the 1930s. This ground-breaking book brings together scholars from the humanities and social and physical sciences to address the question of how recent work in genetics, zoology, and epidemiology can enable a rethinking of the Black Death\u27s global reach and its larger historical significance. It forms the inaugural double issue of The Medieval Globe, a new journal sponsored by the Program in Medieval Studies at the University of Illinois at Urbana-Champaign.
This issue of The Medieval Globe is published with the support of the World History Center at the University of Pittsburgh.https://scholarworks.wmich.edu/medieval_globe/1000/thumbnail.jp
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