269 research outputs found
21 Mobile phone use and brain tumour risk: early warnings, early actions?
categorised the radiation fields from mobile phones and other devices that emit similar non‑ionizing electromagnetic fields (EMFs), as a Group 2B i.e. 'possible ' human carcinogen. Nine years earlier IARC gave the same classification to the magnetic fields from overhead electric power lines. The IARC decision on mobile phones was principally based on two sets of case-control human studies of possible links between mobile phone use and brain tumours: the IARC Interphone study and the Hardell group studies from Sweden. Both provided complementary and generally mutually supportive results. This chapter gives an account of the studies by these two groups — and others coming to different conclusions — as well as reviews and discussions leading up to the IARC decision in 2011. The chapter also describes how different groups have interpreted the authoritative IARC evaluation very differently. There are by now several meta-analyses and reviews on mobile phones and brain tumours, which describe the challenges of doing epidemiology on this issue, the methodological limitations of the major studies published so far and the difficulties of interpreting their results. It has been suggested that national incidence data on brain tumours could be used to qualify or disqualify the association between mobile phones and brain tumours observed in the case‑contro
Ownership and use of wireless telephones: a population-based study of Swedish children aged 7–14 years
<p>Abstract</p> <p>Background</p> <p>Recent years have seen a rapid increase in the use of mobile phones and other sources of microwave radiation, raising concerns about possible adverse health effects. As children have longer expected lifetime exposures to microwaves from these devices than adults, who started to use them later in life, they are a group of special interest.</p> <p>Methods</p> <p>We performed a population-based study to assess ownership and use of mobile phones and cordless phones among children aged 7–14 years. A questionnaire comprising 24 questions was sent to 2000 persons selected from the Swedish population registry using a stratified sampling scheme.</p> <p>Results</p> <p>The response rate was 71.2%. Overall, 79.1% of the respondents reported mobile phone access, and 26.7% of them talked for 2 minutes or more per day. Of those who reported mobile phone access, only 5.9% reported use of hands-free equipment. Use of cordless phones was reported by 83.8% of the respondents and 38.5% of them talked for 5 minutes or more per day. Girls generally reported more frequent use than boys.</p> <p>Conclusion</p> <p>This study showed that most children had access to and used mobile and cordless phones early in life and that there was a rapid increase in use with age. It also showed very low use of hands-free equipment among children with mobile phone access, and finally that girls talked significantly more minutes per day using mobile and cordless phones than boys did.</p
Mass-to-Light Ratios of Galaxy Groups from Weak Lensing
We present the findings of our weak lensing study of a sample of 116 CNOC2
galaxy groups. The lensing signal is used to estimate the mass-to-light ratio
of these galaxy groups. The best fit isothermal sphere model to our lensing
data has an Einstein radius of 0.88"+/-0.12", which corresponds to a
shear-weighted velocity dispersion of 245+/-18 km/s. The mean mass-to-light
ratio within 1 h^-1 Mpc is 185+/-28 h times solar in the B-band and is
independent of radius from the group center.
The signal-to-noise ratio of the shear measurement is sufficient to split the
sample into subsets of "poor" and "rich" galaxy groups. The poor galaxy groups
were found to have an average velocity dispersion of 193+/-38 km/s and a
mass-to-light ratio of 134+/-26 h times solar in the B-band, while the rich
galaxy groups have a velocity dispersion of 270+/-39 km/s and a mass-to-light
ratio of 278+/-42 h times solar in the B-band, similar to the mass-to-light
ratio of clusters. This steep increase in the mass-to-light ratio as a function
of mass, suggests that the mass scale of ~10^13 solar masses is where the
transition between the actively star-forming field environment and the
passively-evolving cluster environment occurs. This is the first such detection
from weak lensing.Comment: Accepted for publication in ApJ 6 pages, 6 figures, uses emulateap
A influência da expressividade emocional na sincronia psicofisiológica
No presente estudo pretendeu-se explorar se há relação entre a expressividade emocional e a sincronia psicofisiológica na dÃade de casal, assim como se a frequência cardÃaca de cada participante se correlaciona com a sua expressividade emocional. E também se a valência de uma tarefa de interação diádica tem implicação na sincronia psicofisiológica da dÃade. Para isso foram realizadas tarefas em que os casais discutiam entre si aspetos positivos e negativos da relação, enquanto era registada a frequência cardÃaca de ambos os membros da dÃade. Não foi encontrada relação entre a sincronia psicofisiológica e expressividade emocional do casal, nem entre a frequência cardÃaca e a expressividade emocional dos participantes. Também não se encontraram diferenças na sincronia entre interações em que a valência foi negativa (i.e. discussão de aspetos negativos da relação), e interações com valência positiva (i.e. discussão de aspetos positivos).The present study intended to explore the relationship between emotional expressiveness and psychophysiological synchrony in the couple dyad, as well as whether the heart rate of each participant is associated with their emotional expressiveness. It was also examined whether the emotional valence of a dyadic interaction task affects the psychophysiological synchrony of the dyad. To that end, eight couples participated in a verbal interaction task in which they discussed among themselves positive and negative aspects of their relationship, while the heart rate of both members was being recorded. No relationship was found between the psychophysiological synchrony and the emotional expressiveness of the couple nor between the heart rate and the emotional expressiveness of the participants in this study. Moreover, there were no differences in the synchrony between interactions with negative valence (i.e. discussion of negative aspects of the relationship), or interactions with positive valence (i.e. discussion of positive aspects of the relationship)
Improvements in X-Ray Spectrometry for Planetary Surface Exploration
Recent innovations in X-ray instrumentation have enabled a new generation of planetary XRS instruments exhibiting performance matching terr estrial laboratory results
Omitting radiotherapy in women >= 65 years with low-risk early breast cancer after breast-conserving surgery and adjuvant endocrine therapy is safe
Purpose: The aim of this study was to verify if radiotherapy (RT) safely can be omitted in older women treated for estrogen-receptor positive early breast cancer with breast-conserving surgery (BCS) and endocrine therapy (ET). Patients and Methods: Eligibility criteria were: consecutive patients with age >= 65 years, BCS + sentinel node biopsy, clear margins, unifocal T1N0M0 breast cancer tumor, Elston-Ellis histological grade 1 or 2 and estrogen receptor-positive tumor. After informed consent, adjuvant ET for 5 years was prescribed. Primary endpoint was ipsilateral breast tumor recurrence (IBTR). Secondary endpoints were contralateral breast cancer and overall survival. Results: Between 2006 and 2012, 603 women were included from 14 Swedish centers. Median age was 71.1 years (range 65-90). After a median follow-up of 68 months 16 IBTR (cumulative incidence at five-year follow-up; 1.2%, 95% CI, 0.6% to 2.5%), 6 regional recurrences (one combined with IBTR), 2 distant recurrences (both without IBTR or regional recurrence) and 13 contralateral breast cancers were observed. There were 48 deaths. One death (2.1%) was due to breast cancer and 13 (27.1%) were due to other cancers (2 endometrial cancers). Five-year overall survival was 93.0% (95% CI, 90.5% to 94.9%). Conclusion: BCS and ET without RT seem to be a safe treatment option in women >= 65 years with early breast cancer and favorable histopathology. The risk of IBTR is comparable to the risk of contralateral breast cancer. Moreover, concurrent morbidity dominates over breast cancer as leading cause of death in this cohort with low-risk breast tumors. (C) 2018 Elsevier Ltd, BASO similar to The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.Peer reviewe
The Evolution of [OII] Emission from Cluster Galaxies
We investigate the evolution of the star formation rate in cluster galaxies.
We complement data from the CNOC1 cluster survey (0.15<z<0.6) with measurements
from galaxy clusters in the 2dF galaxy redshift survey (0.05<z<0.1) and
measurements from recently published work on higher redshift clusters, up to
almost z=1. We focus our attention on galaxies in the cluster core, ie.
galaxies with r<0.7h^{-1}_{70}Mpc. Averaging over clusters in redshift bins, we
find that the fraction of galaxies with strong [OII] emission is < 20% in
cluster cores, and the fraction evolves little with redshift. In contrast,
field galaxies from the survey show a very strong increase over the same
redshift range. It thus appears that the environment in the cores of rich
clusters is hostile to star formation at all the redshifts studied. We compare
this result with the evolution of the colours of galaxies in cluster cores,
first reported by Butcher & Oemler (1984). Using the same galaxies for our
analysis of the [OII] emission, we confirm that the fraction of blue galaxies,
which are defined as galaxies 0.2 mag bluer in the rest frame B-V than the red
sequence of each cluster, increases strongly with redshift. Since the colours
of galaxies retain a memory of their recent star formation history, while
emission from the [OII] line does not, we suggest that these two results can
best be reconciled if the rate at which the clusters are being assembled is
higher in the past, and the galaxies from which it is being assembled are
typically bluer.Comment: 8 pages, 7 figures, accepted for publication in MNRA
Galaxy growth by merging in the nearby universe
We measure the mass growth rate by merging for a wide range of galaxy types.
We present the small-scale (0.014 < r < 11 h70^{-1} Mpc) projected
cross-correlation functions w(rp) of galaxy subsamples from the spectroscopic
sample of the NYU VAGC (5 \times 10^5 galaxies of redshifts 0.03 < z < 0.15)
with galaxy subsamples from the SDSS imaging (4 \times 10^7 galaxies). We use
smooth fits to de-project the two-dimensional functions w(rp) to obtain smooth
three-dimensional real-space cross-correlation functions \xi(r) for each of
several spectroscopic subsamples with each of several imaging subsamples.
Because close pairs are expected to merge, the three-space functions and
dynamical evolution time estimates provide galaxy accretion rates. We find that
the accretion onto massive blue galaxies and onto red galaxies is dominated by
red companions, and that onto small-mass blue galaxies, red and blue galaxies
make comparable contributions. We integrate over all types of companions and
find that at fixed stellar mass, the total fractional accretion rates onto red
galaxies (\sim 1.5 h70 percent per Gyr) is greater than that onto blue galaxies
(\sim 0.5 h70 percent per Gyr). Although these rates are very low, they are
almost certainly over-estimates because we have assumed that all close pairs
merge as quickly as dynamical friction permits.Comment: submitted to APJ on 08/20/201
The evolution of substructure II: linking dynamics to environment
We present results from a series of high-resolution N-body simulations that
focus on the formation and evolution of eight dark matter halos, each of order
a million particles within the virial radius. We follow the time evolution of
hundreds of satellite galaxies with unprecedented time resolution, relating
their physical properties to the differing halo environmental conditions. The
self-consistent cosmological framework in which our analysis was undertaken
allows us to explore satellite disruption within live host potentials, a
natural complement to earlier work conducted within static potentials. Our host
halos were chosen to sample a variety of formation histories, ages, and
triaxialities; despite their obvious differences, we find striking similarities
within the associated substructure populations. Namely, all satellite orbits
follow nearly the same eccentricity distribution with a correlation between
eccentricity and pericentre. We also find that the destruction rate of the
substructure population is nearly independent of the mass, age, and triaxiality
of the host halo. There are, however, subtle differences in the velocity
anisotropy of the satellite distribution. We find that the local velocity bias
at all radii is greater than unity for all halos and this increases as we move
closer to the halo centre, where it varies from 1.1 to 1.4. For the global
velocity bias we find a small but slightly positive bias, although when we
restrict the global velocity bias calculation to satellites that have had at
least one orbit, the bias is essentially removed.Comment: 14 pages, 14 figures, MNRAS in pres
Constraints on intragroup stellar mass from hostless Type Ia supernova
We probe the diffuse stellar mass in a sample of 1401 low redshift galaxy
groups (10E13 - 10E14 Msun/h) by examining the rate of hostless Type Ia
supernova (SNe Ia) within the groups. We correlate the sample of confirmed SNe
Ia from the SDSS supernova survey with the positions of our galaxy groups, as
well as with the resolved galaxies within them. We find that 19 of the 59 SNe
Ia within the group sample have no detectable host galaxy, with another three
ambiguous instances. This gives a robust upper limit that a maximum of 2.69%
+1.58%/-1.34% of the group's total mass arises from diffuse stars in the
intragroup medium. After correcting for a contribution from "prompt" SNe
occurring within galaxies, and including a contribution from those which arise
in dwarf galaxies below our photometric limit, we find that only 1.32%
+0.78%/-0.70% of the group's total mass is likely in the form of diffuse
stellar mass. Combining this result with the galaxy stellar mass functions of
Yang et al., we find that 47% +16%/-15% of the stellar mass in our groups is in
the form of diffuse light, so that stars make up a fraction 0.028 +0.011/-0.010
of the total group mass. Galaxy groups appear to be very efficient in
disrupting stellar mass into a diffuse component; however, stars still make up
a small fraction of the group mass, comparable to that seen in rich clusters.
This remains a challenge to galaxy formation models.Comment: 5 pages, MNRAS Letters, in pres
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