587 research outputs found
Understanding different dominance patterns in western Amazonian forests
Dominance of neotropical tree communities by a few species is widely documented, but dominant trees show a variety of distributional patterns still poorly understood. Here, we used 503 forest inventory plots (93,719 individuals â„2.5âcm diameter, 2609 species) to explore the relationships between local abundance, regional frequency and spatial aggregation of dominant species in four main habitat types in western Amazonia. Although the abundance-occupancy relationship is positive for the full dataset, we found that among dominant Amazonian tree species, there is a strong negative relationship between local abundance and regional frequency and/or spatial aggregation across habitat types. Our findings suggest an ecological trade-off whereby dominant species can be locally abundant (local dominants) or regionally widespread (widespread dominants), but rarely both (oligarchs). Given the importance of dominant species as drivers of diversity and ecosystem functioning, unravelling different dominance patterns is a research priority to direct conservation efforts in Amazonian forests.Publisher PDFPeer reviewe
ÎČ3-adrenergic receptor gene, body mass index, bone mineral density and fracture risk in elderly men and women: the Dubbo Osteoporosis Epidemiology Study (DOES)
BACKGROUND: Recent studies have suggested that the Arg allele of ÎČ3-adrenergic receptor (ADRB3) gene is associated with body mass index (BMI), which is an important predictor of bone mineral density (BMD) and fracture risk. However, whether the ADRB3 gene polymorphism is associated with fracture risk has not been investigated. The aim of study was to examine the inter-relationships between ADRB3 gene polymorphisms, BMI, BMD and fracture risk in elderly Caucasians. METHODS: Genotypes of the ADRB3 gene were determined in 265 men and 446 women aged 60+ in 1989 at entry into the study, whose BMD were measured by DXA (GE Lunar, WI USA) at baseline. During the follow-up period (between 1989 and 2004), fractures were ascertained by reviewing radiography reports and personal interviews. RESULTS: The allelic frequencies of the Trp and the Arg alleles were 0.925 and 0.075 respectively, and the relative frequencies of genotypes Trp/Trp, Trp/Arg and Arg/Arg 0.857, 0.138 and 0.006 respectively. There was no significant association between BMI and ADRB3 genotypes (p = 0.10 in women and p = 0.68 in men). There was also no significant association between ADRB3 genotypes and lumbar spine or femoral neck BMD in either men and women. Furthermore, there were no significant association between ADRB3 genotypes and fracture risk in both women and men, either before or after adjusting for and, BMD and BMI. CONCLUSION: The present data suggested that in Caucasian population the contribution of ADRB3 genotypes to the prediction of BMI, BMD and fracture risk is limited
A note on comonotonicity and positivity of the control components of decoupled quadratic FBSDE
In this small note we are concerned with the solution of Forward-Backward
Stochastic Differential Equations (FBSDE) with drivers that grow quadratically
in the control component (quadratic growth FBSDE or qgFBSDE). The main theorem
is a comparison result that allows comparing componentwise the signs of the
control processes of two different qgFBSDE. As a byproduct one obtains
conditions that allow establishing the positivity of the control process.Comment: accepted for publicatio
Performance and Operation of the CMS Electromagnetic Calorimeter
The operation and general performance of the CMS electromagnetic calorimeter
using cosmic-ray muons are described. These muons were recorded after the
closure of the CMS detector in late 2008. The calorimeter is made of lead
tungstate crystals and the overall status of the 75848 channels corresponding
to the barrel and endcap detectors is reported. The stability of crucial
operational parameters, such as high voltage, temperature and electronic noise,
is summarised and the performance of the light monitoring system is presented
Genetic relatedness of subgingival and buccal Candida dubliniensis isolates in immunocompetent subjects assessed by RAPD-PCR
Advanced Virgo Plus: Future Perspectives
While completing the commissioning phase to prepare the Virgo interferometer for the next joint Observation Run (O4), the Virgo collaboration is also finalizing the design of the next upgrades to the detector to be employed in the following Observation Run (O5). The major upgrade will concern decreasing the thermal noise limit, which will imply using very large test masses and increased laser beam size. But this will not be the only upgrade to be implemented in the break between the O4 and O5 observation runs to increase the Virgo detector strain sensitivity. The paper will cover the challenges linked to this upgrade and implications on the detector's reach and observational potential, reflecting the talk given at 12th Cosmic Ray International Seminar - CRIS 2022 held in September 2022 in Napoli
The Advanced Virgo+ status
The gravitational wave detector Advanced Virgo+ is currently in the commissioning phase in view of the fourth Observing Run (O4). The major upgrades with respect to the Advanced Virgo configuration are the implementation of an additional recycling cavity, the Signal Recycling cavity (SRC), at the output of the interferometer to broaden the sensitivity band and the Frequency Dependent Squeezing (FDS) to reduce quantum noise at all frequencies. The main difference of the Advanced Virgo + detector with respect to the LIGO detectors is the presence of marginally stable recycling cavities, with respect to the stable recycling cavities present in the LIGO detectors, which increases the difficulties in controlling the interferometer in presence of defects (both thermal and cold defects). This work will focus on the interferometer commissioning, highlighting the control challenges to maintain the detector in the working point which maximizes the sensitivity and the duty cycle for scientific data taking
Virgo Detector Characterization and Data Quality during the O3 run
The Advanced Virgo detector has contributed with its data to the rapid growth
of the number of detected gravitational-wave signals in the past few years,
alongside the two LIGO instruments. First, during the last month of the
Observation Run 2 (O2) in August 2017 (with, most notably, the compact binary
mergers GW170814 and GW170817) and then during the full Observation Run 3 (O3):
an 11 months data taking period, between April 2019 and March 2020, that led to
the addition of about 80 events to the catalog of transient gravitational-wave
sources maintained by LIGO, Virgo and KAGRA. These discoveries and the manifold
exploitation of the detected waveforms require an accurate characterization of
the quality of the data, such as continuous study and monitoring of the
detector noise. These activities, collectively named {\em detector
characterization} or {\em DetChar}, span the whole workflow of the Virgo data,
from the instrument front-end to the final analysis. They are described in
details in the following article, with a focus on the associated tools, the
results achieved by the Virgo DetChar group during the O3 run and the main
prospects for future data-taking periods with an improved detector.Comment: 86 pages, 33 figures. This paper has been divided into two articles
which supercede it and have been posted to arXiv on October 2022. Please use
these new preprints as references: arXiv:2210.15634 (tools and methods) and
arXiv:2210.15633 (results from the O3 run
Virgo Detector Characterization and Data Quality: results from the O3 run
The Advanced Virgo detector has contributed with its data to the rapid growth
of the number of detected gravitational-wave (GW) signals in the past few
years, alongside the two Advanced LIGO instruments. First during the last month
of the Observation Run 2 (O2) in August 2017 (with, most notably, the compact
binary mergers GW170814 and GW170817), and then during the full Observation Run
3 (O3): an 11-months data taking period, between April 2019 and March 2020,
that led to the addition of about 80 events to the catalog of transient GW
sources maintained by LIGO, Virgo and now KAGRA. These discoveries and the
manifold exploitation of the detected waveforms require an accurate
characterization of the quality of the data, such as continuous study and
monitoring of the detector noise sources. These activities, collectively named
{\em detector characterization and data quality} or {\em DetChar}, span the
whole workflow of the Virgo data, from the instrument front-end hardware to the
final analyses. They are described in details in the following article, with a
focus on the results achieved by the Virgo DetChar group during the O3 run.
Concurrently, a companion article describes the tools that have been used by
the Virgo DetChar group to perform this work.Comment: 57 pages, 18 figures. To be submitted to Class. and Quantum Grav.
This is the "Results" part of preprint arXiv:2205.01555 [gr-qc] which has
been split into two companion articles: one about the tools and methods, the
other about the analyses of the O3 Virgo dat
Virgo Detector Characterization and Data Quality: tools
Detector characterization and data quality studies -- collectively referred
to as {\em DetChar} activities in this article -- are paramount to the
scientific exploitation of the joint dataset collected by the LIGO-Virgo-KAGRA
global network of ground-based gravitational-wave (GW) detectors. They take
place during each phase of the operation of the instruments (upgrade, tuning
and optimization, data taking), are required at all steps of the dataflow (from
data acquisition to the final list of GW events) and operate at various
latencies (from near real-time to vet the public alerts to offline analyses).
This work requires a wide set of tools which have been developed over the years
to fulfill the requirements of the various DetChar studies: data access and
bookkeeping; global monitoring of the instruments and of the different steps of
the data processing; studies of the global properties of the noise at the
detector outputs; identification and follow-up of noise peculiar features
(whether they be transient or continuously present in the data); quick
processing of the public alerts. The present article reviews all the tools used
by the Virgo DetChar group during the third LIGO-Virgo Observation Run (O3,
from April 2019 to March 2020), mainly to analyse the Virgo data acquired at
EGO. Concurrently, a companion article focuses on the results achieved by the
DetChar group during the O3 run using these tools.Comment: 44 pages, 16 figures. To be submitted to Class. and Quantum Grav.
This is the "Tools" part of preprint arXiv:2205.01555 [gr-qc] which has been
split into two companion articles: one about the tools and methods, the other
about the analyses of the O3 Virgo dat
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