11,434 research outputs found
Taming the waterways: The Europeanization of Southern Québec's riverside landscapes during the 16th–18th centuries
The arrival of Europeans in the New World effected the interaction of 2 temperate biogeographical eco-zones: the Palaearctic and Nearctic. Alfred Crosby has hypothesized that the success of the Europeans as imperialists was due, in part, to the ability of their introduced biota to bring about the collapse of the indigenous populations and local ecosystems, leading to the formation of Neo-European eco-spaces. Through a comparison of paleontological and environmental archaeological data from southern Québec, Canada, we examined Crosby's ecological imperialism model and assessed the biological impact of colonialism on the physical landscape during the 16th to early 18th centuries. The Intendant's Palace site in Québec City is employed as a case study and diachronically contextualized with data from contemporaneous sites in the region. The Europeanization of the landscape as a result of settlement construction, subsistence, and commodification was evidenced through signs of deforestation as well as the arrival of socioeconomic taxa. The biological transfer of European species did not appear to herald the collapse of local ecosystems but rather the establishment of an ecological melting pot along the early colonial waterways of southern Québec
Nuclear Medium Modifications of Hadrons from Generalized Parton Distributions
We study the structure of generalized parton distributions in spin 0 nuclei
within a microscopic approach for nuclear dynamics. GPDs can be used on one
side as tools to unravel the deep inelastic transverse structure of nuclei in
terms of both transverse spatial and transverse momentum degrees of freedom. On
the other, one can obtain information on GPDs themselves by observing how they
become modified in the nuclear environment. We derive the structure of the
nuclear deeply virtual Compton scattering tensor and generalized parton
distributions at leading order in in a field-theoretical framework. The
nuclear generalized parton distributions are calculated using a two step
process -- the convolution approach -- where the scattering process happens
from a quark inside a nucleon, itself inside a nucleus, disregarding final
state interactions with both the nuclear and nucleon debris. We point out that
details of the nuclear long range interactions such as two-body currents, can
be disregarded compared to the deep inelastic induced modifications of the
bound GPDs. We show how the pattern of nuclear modifications predicted, and in
particular the deviations of off-shell effects from the longitudinal
convolution provide clear signals to be sought in experimental measurements.
Finally, we find interesting relationships by studying Mellin moments in
nuclei: in particular we predict the -dependence for the -term of GPDs
within a microscopic approach, and the behavior with of the total momentum
carried by quarks in a nucleus. The latter provides an important element for
the evaluation of nuclear hadronization phenomena which are vital for
interpreting current and future data at RHIC, HERMES and Jefferson Lab.Comment: 29 pages, 10 figure
Herschel-PACS photometry of faint stars
Our aims are to determine flux densities and their photometric accuracy for a
set of seventeen stars that range in flux from intermediately bright (<2.5 Jy)
to faint (>5 mJy) in the far-infrared (FIR). We also aim to derive
signal-to-noise dependence with flux and time, and compare the results with
predictions from the Herschel exposure-time calculation tool. The PACS faint
star sample has allowed a comprehensive sensitivity assessment of the PACS
photometer. Accurate photometry allows us to establish a set of five FIR
primary standard candidates, namely alpha Ari, epsilon Lep, omega,Cap, HD41047
and 42Dra, which are 2 -- 20 times fainter than the faintest PACS fiducial
standard (gamma Dra) with absolute accuracy of <6%. For three of these primary
standard candidates, essential stellar parameters are known, meaning that a
dedicated flux model code may be run.Comment: 42 pages, 12 figure
Output and abatement effects of allocation readjustment in permit trade
In permit trading systems, free initial allocation is common practice. A recent example is the European Union Greenhouse Gas Emission Trading Scheme (EU-ETS). We investigate effects of different free allocation schemes on incentives and identify significant perverse effects on abatement and output employing a simple multi-period model. Firms have incentives for strategic action if allocation in one period depends on their actions in previous ones and thus can be influenced by them. These findings play a major role where trading schemes become increasingly popular as environmental or resource use policy instruments. This is of particular relevance in the EU-ETS where the current period is a trial-period before the first commitment period of the Kyoto protocol. Finally, this paper fills a gap in the literature by establishing a consistent terminology for initial allocatio
Group exercise to improve quality of life among substance use disorder patients
Background: Quality of life (QoL) is a well-established outcome within clinical practice. Despite the adverse effects of substance use disorders on a wide range of patients’ functionality and the multidimensional composition of QoL, the treatment field does not yet systematically assess QoL among patients. Exercise has established positive effects on the QoL of healthy and numerous clinical populations. The potential to integrate exercise within treatment, in order to improve QoL has not been satisfactorily explored. Aims: To measure changes in QoL after group exercise among residential substance use disorder patients and to explore the feasibility of the program within a treatment setting. Methods: We enrolled 35 patients in four long-term residential substance use disorder treatment facilities in Oslo, into a 10-week group exercise program. We analyzed the 24 participants who exercised as completers, while the 11 participants who did not were analyzed as non-completers. We measured QoL, mental distress, somatic health burden and addiction severity at the beginning and end of the program. Results: The program was feasible for participants and the completion rate was 69%. Completers’ physical health domain and psychological health domain of QoL improved significantly. The program engaged the most physically and mentally vulnerable participants, and flexibility and motivational factors were important elements. Conclusions: This study provided promising evidence that low doses of group exercise can yield appreciable benefits, even to patients with more severe health problems
Faults in Linux 2.6
In August 2011, Linux entered its third decade. Ten years before, Chou et al.
published a study of faults found by applying a static analyzer to Linux
versions 1.0 through 2.4.1. A major result of their work was that the drivers
directory contained up to 7 times more of certain kinds of faults than other
directories. This result inspired numerous efforts on improving the reliability
of driver code. Today, Linux is used in a wider range of environments, provides
a wider range of services, and has adopted a new development and release model.
What has been the impact of these changes on code quality? To answer this
question, we have transported Chou et al.'s experiments to all versions of
Linux 2.6; released between 2003 and 2011. We find that Linux has more than
doubled in size during this period, but the number of faults per line of code
has been decreasing. Moreover, the fault rate of drivers is now below that of
other directories, such as arch. These results can guide further development
and research efforts for the decade to come. To allow updating these results as
Linux evolves, we define our experimental protocol and make our checkers
available
Duality of Orthogonal and Symplectic Random Tensor Models: General Invariants
In Gurau and Keppler 2022 (arXiv:2207.01993), a relation between orthogonal
and symplectic tensor models with quartic interactions was proven. In this
paper, we provide an alternative proof that extends to polynomial interactions
of arbitrary order. We consider tensor models of order D with no symmetry under
permutation of the indices that transform in the tensor product of D
fundamental representations of O(N) and Sp(N). We explicitly show that the
models obey the N to -N duality graph by graph in perturbation theory.Comment: 12 pages, 4 figure
Trajectory Anti-Aliasing on Guaranteed-Passive Simulation of Nonlinear Physical Systems
International audienceThis article is concerned with the accurate simulation of passive nonlinear dynamical systems with a particular attention paid on aliasing reduction in the pass-band. The approach is based on the combination of Port-Hamiltonian Systems, continuous-time state-space trajectories reconstruction and exact continuous-time anti-aliasing filter realization. The proposed framework is applied on a nonlinear LC oscillator circuit to study the effectiveness of the method
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