Concerns over the potential impacts of trap fishing on coral reefs and associated habitats prompted a socioeconomic study to characterize the U.S. Caribbean fish trap fishery in anticipation of ...management actions. Stratified random interviews of one hundred fishermen revealed the presence
of a diverse fishery, with appreciable inter-island differences in levels of fishing dependence, fishing practices, and capital investment. High levels of fishing dependence were observed among fishermen in the U.S. Virgin Islands, whereas Puerto Rican fishermen exhibited a more diversified
livelihood strategy. Fishermen from St. Croix derived 62% of their household income from fish traps, significantly more than fishermen from St. Thomas/St. John and Puerto Rico, who derived 45% and 41%, respectively, of their household incomes from fish traps. The St. Thomas/St. John fleet
was also larger and more capital-intensive than the Crucian and Puerto Rican fleets. This structural heterogeneity suggests that fishermen from the various islands may respond differently to the same regulatory constraint. Thus, targeted policies may be necessary to improve the socioeconomic
performance of the fishery and the political acceptability of management actions.
Fishers' Local Ecological Knowledge (LEK) is an important, but largely untapped, source of information about continuity and change in coastal ecosystems. This is due to fishers' continued experience ...in coastal environments, coupled with the nature of their interaction with the ecosystem and the diachronic depth that their knowledge reaches through their lifetimes, as well as through intergenerational communication. In this paper, we will draw upon original research in the Caribbean to describe the extent and scope of tropical small-scale fishers' knowledge of target species biology and ecosystem processes, emphasizing topics where fishers local ecological knowledge can most contribute to the management of tropical coastal ecosystems. We will argue that fishers manage the information necessary to predictably find fish in an uncertain underwater environment with limited gear by 'thinking ecologically', which positions them to contribute to understanding ecosystem-level processes such as habitat connectivity, temporal cycles and patterns, target species responses to environmental (including possible climate) change, dynamics of trophic webs, and indentifying reliable indicators of marine environmental health. We include a discussion of methodological issues pertinent to 1)aeliciting and measuring fishers' local ecological knowledge, and 2)atranslating between local and (Western) scientific ecological knowledge.
This article documents the muon reconstruction and identification efficiency obtained by the ATLAS experiment for 139
fb
-
1
of
pp
collision data at
s
=
13
TeV collected between 2015 and 2018 during ...Run 2 of the LHC. The increased instantaneous luminosity delivered by the LHC over this period required a reoptimisation of the criteria for the identification of prompt muons. Improved and newly developed algorithms were deployed to preserve high muon identification efficiency with a low misidentification rate and good momentum resolution. The availability of large samples of
Z
→
μ
μ
and
J
/
ψ
→
μ
μ
decays, and the minimisation of systematic uncertainties, allows the efficiencies of criteria for muon identification, primary vertex association, and isolation to be measured with an accuracy at the per-mille level in the bulk of the phase space, and up to the percent level in complex kinematic configurations. Excellent performance is achieved over a range of transverse momenta from 3 GeV to several hundred GeV, and across the full muon detector acceptance of
|
η
|
<
2.7
.
Full text
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Discusses the trajectory of the fishermen associations of La Parguera, in the southwest coast of Puerto Rico, as they opposed the development of a marine sanctuary from NOAA. Illustrates the problems ...and socio-political consequences of lack of public participation in the development of management plans. Presents a situation in which the fishermen demonstrated the ability for the effective use and manipulation of the political resources, the media and the public opinion. (Abstract amended)
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A
bstract
A search for charged Higgs bosons decaying into a top quark and a bottom quark is presented. The data analysed correspond to 139 fb
−
1
of proton-proton collisions at
s
= 13 TeV, recorded ...with the ATLAS detector at the LHC. The production of a heavy charged Higgs boson in association with a top quark and a bottom quark,
pp
→
tbH
+
→
tbtb
, is explored in the
H
+
mass range from 200 to 2000 GeV using final states with jets and one electron or muon. Events are categorised according to the multiplicity of jets and
b
-tagged jets, and multivariate analysis techniques are used to discriminate between signal and background events. No significant excess above the background-only hypothesis is observed and exclusion limits are derived for the production cross-section times branching ratio of a charged Higgs boson as a function of its mass; they range from 3.6 pb at 200 GeV to 0.036 pb at 2000 GeV at 95% confidence level. The results are interpreted in the hMSSM and
M
h
125
scenarios.
A
bstract
A search for pair production of third-generation scalar leptoquarks decaying into a top quark and a
τ
-lepton is presented. The search is based on a dataset of
pp
collisions at
s
= 13 TeV ...recorded with the ATLAS detector during Run 2 of the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb
−
1
. Events are selected if they have one light lepton (electron or muon) and at least one hadronically decaying
τ
-lepton, or at least two light leptons. In addition, two or more jets, at least one of which must be identified as containing
b
-hadrons, are required. Six final states, defined by the multiplicity and flavour of lepton candidates, are considered in the analysis. Each of them is split into multiple event categories to simultaneously search for the signal and constrain several leading backgrounds. The signal-rich event categories require at least one hadronically decaying
τ
-lepton candidate and exploit the presence of energetic final-state objects, which is characteristic of signal events. No significant excess above the Standard Model expectation is observed in any of the considered event categories, and 95% CL upper limits are set on the production cross section as a function of the leptoquark mass, for different assumptions about the branching fractions into
tτ
and
bν
. Scalar leptoquarks decaying exclusively into
tτ
are excluded up to masses of 1
.
43 TeV while, for a branching fraction of 50% into
tτ
, the lower mass limit is 1
.
22 TeV.
A
bstract
Measurements of the production cross-sections of the Standard Model (SM) Higgs boson (
H
) decaying into a pair of
τ
-leptons are presented. The measurements use data collected with the ...ATLAS detector from
pp
collisions produced at the Large Hadron Collider at a centre-of-mass energy of
s
= 13 TeV, corresponding to an integrated luminosity of 139 fb
−
1
. Leptonic (
τ
→
ℓν
ℓ
ν
τ
) and hadronic (
τ
→ hadrons
ν
τ
) decays of the
τ
-lepton are considered. All measurements account for the branching ratio of
H → ττ
and are performed with a requirement
|y
H
| <
2
.
5, where
y
H
is the true Higgs boson rapidity. The cross-section of the
pp → H → ττ
process is measured to be 2
.
94
±
0.21
stat
−
0.32
+
0.37
(syst) pb, in agreement with the SM prediction of 3
.
17
±
0
.
09 pb. Inclusive cross-sections are determined separately for the four dominant production modes: 2
.
65
±
0.41
stat
−
0.67
+
0.91
(syst) pb for gluon-gluon fusion, 0
.
197
±
0.028
stat
−
0.026
+
0.032
(syst) pb for vector-boson fusion, 0
.
115
±
0.058
stat
−
0.040
+
0.042
(syst) pb for vector-boson associated production, and 0
.
033
±
0.031
stat
−
0.017
+
0.022
(syst) pb for top-quark pair associated production. Measurements in exclusive regions of the phase space, using the simplified template cross-section framework, are also performed. All results are in agreement with the SM predictions.
A search for a heavy neutral Higgs boson,
A
, decaying into a
Z
boson and another heavy Higgs boson,
H
, is performed using a data sample corresponding to an integrated luminosity of 139 fb
-
1
from ...proton–proton collisions at
s
=
13
TeV
recorded by the ATLAS detector at the LHC. The search considers the
Z
boson decaying into electrons or muons and the
H
boson into a pair of
b
-quarks or
W
bosons. The mass range considered is 230–800
GeV
for the
A
boson and 130–700
GeV
for the
H
boson. The data are in good agreement with the background predicted by the Standard Model, and therefore 95% confidence-level upper limits for
σ
×
B
(
A
→
Z
H
)
×
B
(
H
→
b
b
or
H
→
W
W
)
are set. The upper limits are in the range 0.0062–0.380 pb for the
H
→
b
b
channel and in the range 0.023–8.9 pb for the
H
→
W
W
channel. An interpretation of the results in the context of two-Higgs-doublet models is also given.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A
bstract
The associated production of a Higgs boson and a top-quark pair is measured in events characterised by the presence of one or two electrons or muons. The Higgs boson decay into a
b
-quark ...pair is used. The analysed data, corresponding to an integrated luminosity of 139 fb
−
1
, were collected in proton-proton collisions at the Large Hadron Collider between 2015 and 2018 at a centre-of-mass energy of
s
= 13 TeV. The measured signal strength, defined as the ratio of the measured signal yield to that predicted by the Standard Model, is
0.35
−
0.34
+
0.36
. This result is compatible with the Standard Model prediction and corresponds to an observed (expected) significance of 1.0 (2.7) standard deviations. The signal strength is also measured differentially in bins of the Higgs boson transverse momentum in the simplified template cross-section framework, including a bin for specially selected boosted Higgs bosons with transverse momentum above 300 GeV.
A
bstract
A search for dark matter is conducted in final states containing a photon and missing transverse momentum in proton-proton collisions at
s
= 13 TeV. The data, collected during 2015–2018 by ...the ATLAS experiment at the CERN LHC, correspond to an integrated luminosity of 139 fb
−
1
. No deviations from the predictions of the Standard Model are observed and 95% confidence-level upper limits between 2.45 fb and 0.5 fb are set on the visible cross section for contributions from physics beyond the Standard Model, in different ranges of the missing transverse momentum. The results are interpreted as 95% confidence-level limits in models where weakly interacting dark-matter candidates are pair-produced via an
s
-channel axial-vector or vector mediator. Dark-matter candidates with masses up to 415 (580) GeV are excluded for axial-vector (vector) mediators, while the maximum excluded mass of the mediator is 1460 (1470) GeV. In addition, the results are expressed in terms of 95% confidence-level limits on the parameters of a model with an axion-like particle produced in association with a photon, and are used to constrain the coupling
g
a
Z
γ
of an axion-like particle to the electroweak gauge bosons.
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