1,891 research outputs found
Parametric Study of the Errors Obtained from the Measurement of the Oscillating Movement of a Bridge Using Image Processing
The movement of a pedestrian bridge retrieved by means of image processing technique has been analysed in this paper. An optical target has been attached to the deck and its oscillation has been tracked with fast cameras. The movement of the bridge has also been measured with a radar interferometer and this result has been taken as the reference signal. Using these data, a parametric study of the errors introduced by the image-based methods has been performed. The influence of some variables in the measurement error such as the distance to the target, the image size, the type of camera or the movement amplitude has been analysed for four different distances, and two types of excitations. Results show that the relative error decreases with the amplitude and the target diameter and it increases with the target distance. Additionally, the maximum relative error obtained in most of the analysed cases is below 10 %.The authors acknowledge the support of the Generalitat Valenciana through the project PROMETEO II/2015/015 and GV/2015/116 and the University of Alicante through the project GRE13-10
Reconciling long-term cultural diversity and short-term collective social behavior
An outstanding open problem is whether collective social phenomena occurring
over short timescales can systematically reduce cultural heterogeneity in the
long run, and whether offline and online human interactions contribute
differently to the process. Theoretical models suggest that short-term
collective behavior and long-term cultural diversity are mutually excluding,
since they require very different levels of social influence. The latter
jointly depends on two factors: the topology of the underlying social network
and the overlap between individuals in multidimensional cultural space.
However, while the empirical properties of social networks are well understood,
little is known about the large-scale organization of real societies in
cultural space, so that random input specifications are necessarily used in
models. Here we use a large dataset to perform a high-dimensional analysis of
the scientific beliefs of thousands of Europeans. We find that inter-opinion
correlations determine a nontrivial ultrametric hierarchy of individuals in
cultural space, a result unaccessible to one-dimensional analyses and in
striking contrast with random assumptions. When empirical data are used as
inputs in models, we find that ultrametricity has strong and counterintuitive
effects, especially in the extreme case of long-range online-like interactions
bypassing social ties. On short time-scales, it strongly facilitates a
symmetry-breaking phase transition triggering coordinated social behavior. On
long time-scales, it severely suppresses cultural convergence by restricting it
within disjoint groups. We therefore find that, remarkably, the empirical
distribution of individuals in cultural space appears to optimize the
coexistence of short-term collective behavior and long-term cultural diversity,
which can be realized simultaneously for the same moderate level of mutual
influence
Post-release mortality of shortfin mako in the Atlantic using satellite telemetry: preliminary results
This paper provides an update of the study on post-release mortality of the shortfin mako, Isurus oxyrinchus developed within the ICCAT Shark Research and Data Collection Program (SRDCP). Up to date, 34 tags (14 sPATs and 20 miniPATs) have been deployed by observers on Brazilian, Portuguese, Uruguayan, and US vessels in the temperate NE and NW, Equatorial and SW Atlantic. Data from 28 out of 34 tagged specimens could be used to obtain preliminary information regarding post-release mortality, resulting in a total of 7 mortality and 21 survival events.This study was carried out as part of a cooperative work conducted by the ICCAT Shark species group integrated in
the ICCAT Shark Research and Data Collection Program (SRDCP). The authors are grateful to all fishery observers
and longline skippers from the Nations involved in this study. Tags from additional sources have been contributed
and deployed with several national Projects, specifically: Project "LL-Sharks: Mitigação das capturas de tubarões na
pescaria de palangre de superfície (Ref: 31-03-05-FEP-44, funded by PROMAR)", Project "MAKO-WIDE - "A
wide scale inter-hemispheric and inter-disciplinary study aiming the conservation of the shortfin mako shark in the
Atlantic Ocean (Ref: FAPESP/19740/2014)", funded by FCT (Portuguese Foundation for Science and Technology)
and FAPESP (São Paulo Research Foundation, Brazil), and Project SAFEWATERS SC7 (The provision of advice
on the conservation of pelagic sharks associated to fishing activity under EU Sustainable Fisheries Partnership
Agreements in the Atlantic Ocean) under the Framework Contract MARE/2012/21, funded by the European
Commission. Additional satellite tags were acquired by NOAA in US-Uruguay and US-Portugal-Uruguay
collaboration initiatives. Rui Coelho is supported by an Investigador-FCT contract from the Portuguese Foundation
for Science and Technology (FCT) supported by the EU European Social Fund and the Programa Operacional
Potencial Humano (Ref: IF/00253/2014).info:eu-repo/semantics/draf
Updates on post-release mortality of shortfin mako in the Atlantic using satellite telemetry
This paper provides an update of the study on post-release mortality of the shortfin mako, Isurus oxyrinchus developed within the ICCAT Shark Research and Data Collection Program (SRDCP). Up to date, 43 tags (14 sPATs and 29 miniPATs) have been deployed by observers on Brazilian, Portuguese, Spanish, Uruguayan, and US vessels in the temperate NE and NW, Equatorial and SW Atlantic. Data from 35 out of 43 tagged specimens could be used to obtain preliminary information regarding post-release mortality, resulting in a total of 8 mortality and 27 survival events.This study was carried out as part of a cooperative work conducted by the ICCAT Shark species group integrated in
the ICCAT Shark Research and Data Collection Program (SRDCP). The authors are grateful to all fishery observers
and longline skippers from the Nations involved in this study. Tags from additional sources have been contributed
and deployed with several national Projects, specifically: Project "LL-Sharks: Mitigação das capturas de tubarões na
pescaria de palangre de superfície (Ref: 31-03-05-FEP-44, funded by PROMAR)", Project "MAKO-WIDE - "A
wide scale inter-hemispheric and inter-disciplinary study aiming the conservation of the shortfin mako shark in the
Atlantic Ocean (Ref: FAPESP/19740/2014)", funded by FCT (Portuguese Foundation for Science and Technology)
and FAPESP (São Paulo Research Foundation, Brazil), and Project SAFEWATERS SC7 (The provision of advice
on the conservation of pelagic sharks associated to fishing activity under EU Sustainable Fisheries Partnership
Agreements in the Atlantic Ocean) under the Framework Contract MARE/2012/21, funded by the European
Commission. Additional satellite tags were acquired by NOAA in US-Uruguay and US-Portugal-Uruguay
collaboration initiatives. Rui Coelho is supported by an Investigador-FCT contract from the Portuguese Foundation
for Science and Technology (FCT) supported by the EU European Social Fund and the Programa Operacional
Potencial Humano (Ref: IF/00253/2014). Catarina C. Santos is supported by an FCT Doctoral grant (Ref:
SFRH/BD/139187/2018).info:eu-repo/semantics/draf
Del postmodernismo a las nuevas geografías culturales (mesa redonda del XVIII Congreso de la AGE. Bellaterra, 26 de septiembre de 2003)
Els quatre textos que composen aquesta taula rodona tracten, des de diverses perspectives metodològiques les aportacions més recents en geografia humana de teoria i metodologia.Los cuatro textos que componen esta mesa redonda tratan, desde diversas perspectivas metodológicas las aportaciones más recientes en geografía humana de teoría y metodología.The four texts of this round table presents, from different methodological standpoints the most recent methodological and theoretical contributions in human geography
Shark Research and Data Collection Program: progress on the age and growth of the shortfin mako in the Atlantic Ocean
This paper presents an update of the age and growth study within the ICCAT Shark Research and Data Collection Program (SRDCP), including the current development status and plans for the 2nd phase of the project. There are currently 469 vertebrae samples (205 females, 257 males and 7 specimens with unidentified sex) collected and processed from both the North and Southern hemispheres. The sample distribution is much more complete in the north, while in the south at this stage there are only samples from the equatorial region. The size range of the samples varies from 52 cm to 366 cm FL. The next steps of this projects is proposing a workshop on age reading and growth in order to prepare a reference set of vertebrae that can be used as a guideline for the readings of the remaining sample, and also discuss aspects of age validation and band deposition periodicity. The final results will be presented to the SCRS sharks working group in 2017, in order to contribute to the 2017 shortfin mako stock assessment.info:eu-repo/semantics/publishedVersio
Influence of endothelial nitric oxide synthase polymorphisms in Psoriasis risk
Nitric oxide (NO) is a potent regulator of keratinocyte growth and differentiation that has been implicated in the pathogenesis of psoriasis (Ps). The NOS3 -786 T/C (SNP id rs2070744; www.ensembl.org ), intron 4 variable number tandem repeat (VNTR), and Glu298Asp (SNP id rs1799983) polymorphisms, have been associated with differences in NO plasma concentrations and with the risk of hypertension (HT) and ischemic cardiac disease (IC). The aim of this study was to determine whether the above mentioned NOS3 variants contributed to the risk of Ps, and were associated with the risk for HT and CAD in these patients. A total of 368 patients with chronic plaque Ps and 400 healthy controls were genotyped for the NOS3 -786 T/C, intron 4 VNTR, and Glu298Asp polymorphisms. Carriers of the -786 C allele were significantly more frequent among the patients (p<0.001). Carriers of the 4-repeats allele (45+44 genotypes) were also more frequent a (p<0.001). No significant difference was found for the Glu298Asp polymorphism. None of the NOS3 variants was associated with Ht and CAD in our population. In conclusion, NOS3 gene polymorphism would be risk factors for developing Ps
Nuclear activity and massive star formation in the low luminosity AGN NGC4303: Chandra X-ray observations
We present evidence of the co-existence of either an AGN or an ultraluminous
X-ray source (ULX), together with a young super stellar cluster in the 3
central parsecs of NGC4303. The galaxy contains a low luminosity AGN and hosts
a number of starburst regions in a circumnuclear spiral, as well as in the
nucleus itself. A high spatial resolution Chandra image of this source reveals
that the soft X-ray emission traces the ultraviolet nuclear spiral down to a
core, which is unresolved both in soft and hard X-rays. The astrometry of the
X-ray core coincides with the UV core within the Chandra positioning accuracy.
The total X-ray luminosity of the core, 1.5*10^{39} erg/s, is similar to that
from some LINERs or from the weakest Seyferts detected so far. The soft X-rays
in both the core and the extended structure surrounding it can be well
reproduced by evolutionary synthesis models (which include the emission
expected from single stars, the hot diffuse gas, supernova remnants and binary
systems), consistent with the properties of the young stellar clusters
identified in the UV. The hard X-ray tail detected in the core spectrum,
however, most likely requires the presence of an additional source. This
additional source could either be a weak active nucleus black hole or an
ultraluminous X-ray object. The implications of these results are discussed.Comment: 37 pages, 7 figures, ApJ accepte
Habitat use and migrations of shortfin mako in the atlantic using satellite telemetry
This paper provides an update of the study on habitat use for shortfin mako, developed within the ICCAT Shark Research and Data Collection Program (SRDCP). Currently, all phase 1 (2015-2016) tags (23 tags: 9 miniPATs and 14 sPAT) and 11 tags from phase 2 (2016-2018) have been deployed by observers on Portuguese, Uruguayan, Brazilian and US vessels in the temperate NE and NW, Equatorial and SW Atlantic. Data from 32 tags/specimens is available and a total of 1260 tracking days have been recorded. Results showed shortfin makos moved in multiple directions, travelling considerable distances. Shortfin mako sharks spent most of their time above the thermocline (0-90 m), between 18 and 22 °C. The main plan for the next phase of the project is to continue the tag deployment during 2018 in several regions of the Atlantic.info:eu-repo/semantics/publishedVersio
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