25,052 research outputs found
Laboratory study of the impact of repetitive electrical and mechanical stimulation on brown shrimp Crangon crangon
Pulse trawling is currently the best available alternative to beam trawling in the brown shrimp Crangon crangon and Sole Solea solea (also known as Solea vulgaris) fisheries. To evaluate the effect of repetitive exposure to electrical fields, brown shrimp were exposed to the commercial electrodes and pulse settings used to catch brown shrimp (shrimp startle pulse) or Sole (Sole cramp pulse) 20 times in 4 d and monitored for up to 14 d after the first exposure. Survival, egg loss, molting, and the degree of intranuclear bacilliform virus (IBV) infection were evaluated and compared with those in stressed but not electrically exposed (procedural control) and nonstressed, nonexposed (control) brown shrimp as well as brown shrimp exposed to mechanical stimuli. The lowest survival at 14 d (57.3%) occurred in the Sole cramp pulse treatment, and this was significantly lower than in the group with the highest survival, the procedural control (70.3%). No effect of electrical stimulation on the severity of IBV infection was found. The lowest percentage of molts occurred in the repetitive mechanical stimulation treatment (14.0%), and this was significantly lower than in the group with the highest percentage of molts, the procedural control (21.7%). Additionally, the mechanically stimulated brown shrimp that died during the experiment had a significantly larger size than the surviving individuals. Finally, no effect of the shrimp startle pulse was found. Therefore, it can be concluded that repetitive exposure to a cramp stimulus and mechanical stimulation may have negative effects on the growth and/or survival of brown shrimp. However, there is no evidence that electrical stimulation during electrotrawls would have a larger negative impact on brown shrimp stocks than mechanical stimulation during conventional beam trawling
Optimal Data-Dependent Hashing for Approximate Near Neighbors
We show an optimal data-dependent hashing scheme for the approximate near
neighbor problem. For an -point data set in a -dimensional space our data
structure achieves query time and space , where for the Euclidean space and
approximation . For the Hamming space, we obtain an exponent of
.
Our result completes the direction set forth in [AINR14] who gave a
proof-of-concept that data-dependent hashing can outperform classical Locality
Sensitive Hashing (LSH). In contrast to [AINR14], the new bound is not only
optimal, but in fact improves over the best (optimal) LSH data structures
[IM98,AI06] for all approximation factors .
From the technical perspective, we proceed by decomposing an arbitrary
dataset into several subsets that are, in a certain sense, pseudo-random.Comment: 36 pages, 5 figures, an extended abstract appeared in the proceedings
of the 47th ACM Symposium on Theory of Computing (STOC 2015
The ethical beliefs and behaviours of Victorian fitness professionals
A survey based on those employed by Petitpas, Brewer, Rivera, and Van Raalte (1994), Pope, Tabachnick, and Keith-Spiegel (1987), Tabachnick, Keith-Spiegel, and Pope (1991), and Pope and Vetter (1992) was used to investigate the ethical beliefs and behaviours of Victorian fitness professionals. Although there is evidence that Victorian fitness professionals are knowledgeable about some general ethical principles, the results of this study suggest that there is some lack of consensus among Victorian fitness professionals about the ethical appropriateness of a number of complex issues relating to business practices, confidentiality, dual relationships, and personal and professional boundaries. The findings suggest there is a need to improve the professional and ethical education of fitness professionals and to develop comprehensive ethical principles and a code of conduct that is relevant to the individuals working in the Australian fitness profession
The Boltzmann factor, DNA melting, and Brownian ratchets: Topics in an introductory physics sequence for biology and premedical students
Three, interrelated biologically-relevant examples of biased random walks are
presented: (1) A model for DNA melting, modelled as DNA unzipping, which
provides a way to illustrate the role of the Boltzmann factor in a venue
well-known to biology and pre-medical students; (2) the activity of helicase
motor proteins in unzipping double-stranded DNA, for example, at the
replication fork, which is an example of a Brownian ratchet; (3) force
generation by actin polymerization, which is another Brownian ratchet, and for
which the force and actin-concentration dependence of the velocity of actin
polymerization is determined
Pylons in the back yard: local planning and perceived risks to health
Health fears arising from the presence of high-voltage power lines in residential areas have received recent attention in spatial planning. A study of stances taken by planning authorities in England and Wales shows their willingness to give expression to the concerns of local communities through precautionary measures, and the difficulties encountered in the face of official statements and industry opposition. These attempts to embody local feeling in patterns of development are illustrative of the increasing prevalence of a sense of risk in contemporary society. The spatial patterns of risk are also revealed, which owe much to the presence and distribution of industrial infrastructure in the landscape and to the associated contested use of land.</p
Bridging Physics and Biology Teaching through Modeling
As the frontiers of biology become increasingly interdisciplinary, the
physics education community has engaged in ongoing efforts to make physics
classes more relevant to life sciences majors. These efforts are complicated by
the many apparent differences between these fields, including the types of
systems that each studies, the behavior of those systems, the kinds of
measurements that each makes, and the role of mathematics in each field.
Nonetheless, physics and biology are both sciences that rely on observations
and measurements to construct models of the natural world. In the present
theoretical article, we propose that efforts to bridge the teaching of these
two disciplines must emphasize shared scientific practices, particularly
scientific modeling. We define modeling using language common to both
disciplines and highlight how an understanding of the modeling process can help
reconcile apparent differences between the teaching of physics and biology. We
elaborate how models can be used for explanatory, predictive, and functional
purposes and present common models from each discipline demonstrating key
modeling principles. By framing interdisciplinary teaching in the context of
modeling, we aim to bridge physics and biology teaching and to equip students
with modeling competencies applicable across any scientific discipline.Comment: 10 pages, 2 figures, 3 table
Integrating crime prevention into urban design and planning
Purpose: This paper aims to understand the delivery of Crime Prevention Through Environmental Design (CPTED) across Europeâfrom European-wide procedures, through national schemes to effective local strategies.
Methodology: The findings come from a review of published literature and reports, case studies and site visits conducted primarily during COST Action TU1203 (2013â16).
Findings: Innovative approaches and methods to integrate crime prevention into urban design, planning and management have been generated by multi-agency partnerships and collaborations at European, national and city levels. Methods and procedures developed by the European Committee for Standardization (CEN) Working Group on âCrime Prevention through Urban Planning and Building Designâ are pioneering. However, findings show that implementation is best achieved at a local level using methods and procedures tailored to the specific context.
Practical and research implications: In-depth research is required to appreciate subtle differences between local approaches and conceptual models developed to better understand approaches and methods. In addition, practitioners and academics working to prevent crime benefit from participation in focused, multi-agency collaborations that, importantly, facilitate visits to urban developments, discussions with local stakeholders responsible for delivery âon the groundâ and structured and sustained exploration of innovations and challenges.
Originality / value: The authors hope that this paper will contribute to developing a new direction for CPTED practice and research that builds on significant progress in creating safer environments over previous decades
NEXUS/Physics: An interdisciplinary repurposing of physics for biologists
In response to increasing calls for the reform of the undergraduate science
curriculum for life science majors and pre-medical students (Bio2010,
Scientific Foundations for Future Physicians, Vision & Change), an
interdisciplinary team has created NEXUS/Physics: a repurposing of an
introductory physics curriculum for the life sciences. The curriculum interacts
strongly and supportively with introductory biology and chemistry courses taken
by life sciences students, with the goal of helping students build general,
multi-discipline scientific competencies. In order to do this, our two-semester
NEXUS/Physics course sequence is positioned as a second year course so students
will have had some exposure to basic concepts in biology and chemistry.
NEXUS/Physics stresses interdisciplinary examples and the content differs
markedly from traditional introductory physics to facilitate this. It extends
the discussion of energy to include interatomic potentials and chemical
reactions, the discussion of thermodynamics to include enthalpy and Gibbs free
energy, and includes a serious discussion of random vs. coherent motion
including diffusion. The development of instructional materials is coordinated
with careful education research. Both the new content and the results of the
research are described in a series of papers for which this paper serves as an
overview and context.Comment: 12 page
Don't know, can't know: Embracing deeper uncertainties when analysing risks
This article is available open access through the publisherâs website at the link below. Copyright @ 2011 The Royal Society.Numerous types of uncertainty arise when using formal models in the analysis of risks. Uncertainty is best seen as a relation, allowing a clear separation of the object, source and âownerâ of the uncertainty, and we argue that all expressions of uncertainty are constructed from judgements based on possibly inadequate assumptions, and are therefore contingent. We consider a five-level structure for assessing and communicating uncertainties, distinguishing three within-model levelsâevent, parameter and model uncertaintyâand two extra-model levels concerning acknowledged and unknown inadequacies in the modelling process, including possible disagreements about the framing of the problem. We consider the forms of expression of uncertainty within the five levels, providing numerous examples of the way in which inadequacies in understanding are handled, and examining criticisms of the attempts taken by the Intergovernmental Panel on Climate Change to separate the likelihood of events from the confidence in the science. Expressing our confidence in the adequacy of the modelling process requires an assessment of the quality of the underlying evidence, and we draw on a scale that is widely used within evidence-based medicine. We conclude that the contingent nature of risk-modelling needs to be explicitly acknowledged in advice given to policy-makers, and that unconditional expressions of uncertainty remain an aspiration
- âŠ