1,275 research outputs found
Photometric observations of Southern Abell Cluster Redshifts Survey Clusters: Structure of galaxies in the inner region of clusters of galaxies
We analyze photometric properties of 1384 cluster galaxies as a function of
the normalized distance to cluster center. These galaxies were selected in the
central region ( 0.8) of 14 southern Abell clusters chosen from
the Southern Abell Cluster Redshifts Survey (SARS). For 507 of these galaxies
we also obtained their luminosity profiles. We have studied the
morphology-clustercentric distance relation on the basis of the shape parameter
of the S\'ersic's law. We also have analyzed the presence of a possible
segregation in magnitude for both, the galaxy total luminosity and that of
their components (i.e. the bulge and the disk).
Results show a marginal ( level) decrease of the total luminosity as
a function of normalized radius. However, when bulges are analyzed separately,
a significant luminosity segregation is found ( and for
galaxies in projection and member galaxies respectively). The fraction of
bulges brighter than is three times larger in the core of
clusters than in the outer region. Our analysis of the disk component suggests
that disks are, on average, less luminous in the cluster core than at
. In addition, we found that the magnitude-size relation as
a function of indicates (at level) that disks are smaller
and centrally brighter in the core of clusters. However, the Kormendy relation
(the bulge magnitude-size relation) appears to be independent of environment.Comment: To appear in the A
Risk perception of air pollution: A systematic review focused on particulate matter exposure
The adverse health effects of exposure to air pollutants, notably to particulate matter (PM), are well-known, as well as the association with measured or estimated concentration levels. The role of perception can be relevant in exploring effects and pollution control actions. The purpose of this study was to explore studies that analyse people’s perception, together with the measurement of air pollution, in order to elucidate the relationship between them. We conducted a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. In March 2020, PubMed, EMBASE, and Scopus databases were explored in an attempt to search for studies published from 2000 to 2020. The review included 38 studies, most of which were conducted in China (n = 13) and the United States (n = 11) and published over the last four years (n = 26). Three studies were multicenter investigations, while five articles were based on a national-level survey. The air quality (AQ) was assessed by monitoring stations (n = 24) or dispersion models (n = 7). Many studies were population questionnaire-based, air monitoring and time-series studies, and web-based investigations. A direct association between exposure and perception emerged in 20 studies. This systematic review has shown that most of the studies establish a relationship between risk perception measurement. A broad spectrum of concepts and notions related to perception also emerged, which is undoubtedly an indicator of the wealth of available knowledge and is promising for future research
Role of meteorological factors on SARS-CoV-2 infection incidence in Italy and Spain before the vaccination campaign. A multi-city time series study
Numerous studies have been conducted worldwide to investigate if an association exists between meteorological factors and the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection incidence. Although research studies provide conflicting results, which can be partially explained by different methods used, some clear trends emerge on the role of weather conditions and SARS-CoV-2 infection, especially for temperature and humidity. This study sheds more light on the relationship between meteorological factors and SARS-CoV-2 infection incidence in 23 Italian and 52 Spanish cities. For the purposes of this study, daily air temperature, absolute and relative humidity, wind speed, ultraviolet radiation, and rainfall are considered exposure variables. We conducted a two-stage meta-regression. In the first stage, we estimated the exposure-response association through time series regression analysis at the municipal level. In the second stage, we pooled the association parameters using a meta-analytic model. The study demonstrates an association between meteorological factors and SARS-CoV-2 infection incidence. Specifically, low levels of ambient temperatures and absolute humidity were associated with an increased relative risk. On the other hand, low and high levels of relative humidity and ultraviolet radiation were associated with a decreased relative risk. Concerning wind speed and rainfall, higher values contributed to the reduction of the risk of infection. Overall, our results contribute to a better understanding of how the meteorological factors influence the spread of the SARS-CoV-2 and should be considered in a wider context of existing robust literature that highlight the importance of measures such as social distancing, improved hygiene, face masks and vaccination campaign
MicroRNAs and cancer metabolism reprogramming : the paradigm of metformin
Increasing evidence witnesses that cancer metabolism alterations represent a critical hallmark for many types of human tumors. There is a strong need to understand and dissect the molecular mechanisms underlying cancer metabolism to envisage specific biomarkers and underpin critical molecular components that might represent novel therapeutic targets. One challenge, that is the focus of this review, is the reprogramming of the altered metabolism of a cancer cell toward that of un-transformed cell. The anti-hyperglicemic agent, metformin has proven to be effective in reprogramming the metabolism of cancer cells even from those subpopulations endowed with cancer stem like features and very high chemoresistenace to conventional anticancer treatments. A functional interplay involving selective modulation of microRNAs (miRNAs) takes place along the anticancer metabolic effects exerted by metformin. The implications of this interplay will be also discussed in this review
Prone positioning and convalescent plasma therapy in a critically ill pregnant woman with COVID-19
Prone positioning is feasible in pregnancy and may have contributed to the positive outcome in this case. Doctors should not be reluctant to move a patient to a prone position just because they are pregnant
Complete validation of plumbline distances as a screening tool for sagittal plane deformities
Particulate matter exposure and attention-deficit/hyperactivity disorder in children: A systematic review of epidemiological studies
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