1,599 research outputs found
Maximum thickness of a two-dimensional trapped Bose system
The trapped Bose system can be regarded as two-dimensional if the thermal
fluctuation energy is less than the lowest energy in the perpendicular
direction. Under this assumption, we derive an expression for the maximum
thickness of an effective two-dimensional trapped Bose system.Comment: 1 pages, 0 figure
VELOS : a VR platform for ship-evacuation analysis
Virtual Environment for Life On Ships (VELOS) is a multi-user Virtual Reality (VR) system that aims to support designers to assess (early in the design process) passenger and crew activities on a ship for both normal and hectic conditions of operations and to improve ship design accordingly. This article focuses on presenting the novel features of VELOS related to both its VR and evacuation-specific functionalities. These features include: (i) capability of multiple users’ immersion and active participation in the evacuation process, (ii) real-time interactivity and capability for making on-the-fly alterations of environment events and crowd-behavior parameters, (iii) capability of agents and avatars to move continuously on decks, (iv) integrated framework for both the simplified and advanced method of analysis according to the IMO/MSC 1033 Circular, (v) enrichment of the ship geometrical model with a topological model suitable for evacuation analysis, (vi) efficient interfaces for the dynamic specification and handling of the required heterogeneous input data, and (vii) post-processing of the calculated agent trajectories for extracting useful information for the evacuation process. VELOS evacuation functionality is illustrated using three evacuation test cases for a ro–ro passenger ship
Re-evaluating the notion of value in wildlife trade research from a service marketing perspective
The trade in wildlife and wildlife products is one of the leading causes of population decline for thousands of species. It is critical that researchers use all available theories and techniques at hand to tackle this conservation crisis. Here, we integrate current services marketing theory with our existing understanding of behaviour change in wildlife trade research and propose future areas of transdisciplinary research. We first used the Preferred Reporting Items for Systematic review and Meta Analysis methodology to perform a systematic literature review of 227 articles from 76 journals to explore the current understanding of value in wildlife trade literature. Our results showed over 90% of articles used the term value to describe monetary worth and no articles provided a definition or justification of this use. We then contribute to scientific discourse by presenting Service Dominant Logic from marketing theory as a novel lens through which to explore consumer behaviour and the concept of value in the wildlife trade. We outline future avenues of research that will improve the ability of conservation practitioners to create meaningful behaviour change and system transformation using a wholly novel conceptualisation that synthesises the two disciplines of marketing and conservation
Normal redefined: Exploring decontextualization of lorises (Nycticebus & Xanthonycticebus spp.) on social media platforms
Introduction: Decontextualization is a concept from psychology whereby new words are learned outside of the context of the here-and-now. Decontextualized language is used for discussing abstract concepts and is crucial to the development of academic language. When it comes to images, a dearth of context can lead to a lack of clarity, such as the use of ambiguous decontextualized images in environmental communication, leading to the promotion of greenwashing. Here we refer to decontextualization as the removal of wildlife from their wild ecological context. Images and videos of globally threatened species are increasingly popular on social media. Showing such taxa alongside humans may impact public perceptions of their abundance and need for conservation and can increase illegal trade. One group of animals that are particularly popular on social media platforms are the slow and pygmy lorises (Nycticebus spp., Xanthonycticebus spp.). Methods: Here, we examined 100 videos from three popular social media platforms (YouTube, TikTok, and Giphy) to calculate how often and in which ways these videos remove slow lorises from their natural ecological and behavioural context. We also examined views and likes to determine viewer engagement trends. We used relevant content from each site to assess the presence of decontextualization using five conditions. Results: In all but two videos, conditions of decontextualization were present and 77% of all videos had four to five conditions of decontextualization. Using Spearman correlation, we found a significant effect of decontextualization scores on the number of views and likes for YouTube and TikTok videos. Views were significantly higher when videos presented animals in anthropogenic settings (i.e., in human-made structures or in proximity of human artefacts). Additionally, views on TikTok and YouTube were significantly higher when animals displayed signs of stress or ill health and when they were in unnatural conditions. Discussion: Our case study of lorises provides an example of the danger of decontextualizing wild animals on social media. Public preference for imagery where animals are neglected is indicative that better guidelines need to be put in place and policed by social media platforms. Additionally, conservationists need to develop strategies to promote wild imagery and further explore decontextualization if we are to understand and address the drivers of the rampant illegal wildlife trade online
РЕЗУЛЬТАТЫ ОДНОМОМЕНТНОЙ КОРРЕКЦИИ КОАРКТАЦИИ АОРТЫ И ИНТРАКАРДИАЛЬНОЙ ПАТОЛОГИИ У ДЕТЕЙ ПЕРВОГО ГОДА ЖИЗНИ
Background: The aim of the study was to compare the outcomes of hypothermic circulatory arrest (GCA) and selective cerebral perfusion (SCP). Patients and methods: Nine patients were treated at the Bakoulev Center for Cardiovascular Surgery. All congenital heart diseases were repaired simultaneously. Group 1 (n =4) included infants who were treated using an HCA, and the patients who underwent repair with the use of SCP were in group 2 (n =5). Results: One patient (25%) in group 1 died in the period of thirty days after the repair. Moderate heart failure and respiratory failure occurred postoperatively with no significant difference between two groups. Recoarctation was a frequent (75%) complication after the «end to end» anastomosis creating. One patient (25%) was reoperated on day 3 after the primary repair. Two other patients (50%) were treated by balloon angioplasty. There was relatively high (75%) incidence of a prolonged open sternotomy in group 1. Conclusion: There were similar results in HCA and SCP groups. A tendency for frequent prolonged open sternotomy application after HCA surgery as well as occurrence of the recoarctation after «end to end» anastomosis creating was found.Цель исследования: сравнить результаты одномоментной коррекции, выполненной в условиях гипотермического циркуляторного ареста (ГЦА) или селективной церебральной перфузии (СЦП). Пациенты и методы: 9 пациентов первого года жизни были прооперированы в НЦ сердечно-сосудистой хирургии им. А.Н. Бакулева. Всем больным были одномоментно устранены все врожденные пороки сердца (ВПС). В группу 1 (n =4) вошли дети, оперированные с применением ГЦА, в группу 2 (n =5) — больные, коррекция ВПС которым выполнялась в условиях СЦП. Результаты: в тридцатидневный срок после операции погиб 1 (25%) пациент в группе 1. Среди осложнений раннего послеоперационногопериода зарегистрированы умеренная сердечная и дыхательная недостаточность. Не выявлено значимых различий в частоте возникновения данных осложнений в обеих группах. Отмечена высокая частота рекоарктации аорты (75%) у пациентов, которым реконструкция аорты была выполнена путем анастомоза «конец в конец». 1 пациент (25%) с рекоарктацией был реоперирован на 3-и сут после первичной коррекции, еще 2 (50%) больным рекоарктация аорты была устранена посредством транслюминальной баллонной ангиопластики. В группе 1 отмечена сравнительно высокая (75%) необходимость применения метода пролонгированной открытой стернотомии. Выводы: результатыприменения методов ГЦА и СЦП схожи по большинству показателей. Обнаружена тенденция к повышенной частоте использования методапролонгированной открытой стернотомии после операций с применением ГЦА, а также склонность к высокой частоте возникновения рекоарктации аорты после реконструкции аорты путем анастомоза «конец в конец»
Antiferromagnetic order and the structural order-disorder transition in the Cd6Ho quasicrystal approximant
International audienceIt has generally been accepted that the orientational ordering of the Cd4 tetrahedron within the Cd6 R quasicrystal approximants is kinetically inhibited for R = Ho, Er, Tm and Lu by steric constraints. Our high-resolution X-ray scattering measurements of the Cd6Ho quasicrystal approximant, however, reveal an abrupt (first-order) transition to a monoclinic structure below T S = 178 K for samples that have 'aged' at room temperature for approximately one year, reopening this question. Using X-ray resonant magnetic scattering at the Ho L 3-edge we have elucidated the nature of the antiferromagnetic ordering below T N = 8.5 K in Cd6Ho. The magnetic Bragg peaks are found at the charge forbidden H + K + L = 2n + 1 positions, referenced to the high-temperature body-centred cubic structure. In general terms, this corresponds to antiferromagnetic arrangements of the Ho moments on adjacent clusters in the unit cell as previously found for Cd6Tb
Modelling of Tirapazamine effects on solid tumour morphology
Bioreductive drugs are in clinical practice to exploit the resistance from tumour microenvironments especially in the hypoxic region of tumour. We pre-sented a tumour treatment model to capture the pharmacology of one of the most prominent bioreductive drugs, Tirapazamine (TPZ) which is in clinical trials I and II. We calculated solid tumour mass in our previous work and then integrated that model with TPZ infusion. We calculated TPZ cytotoxicity, concentration, penetra-tion with increasing distance from blood vessel and offered resistance from micro-environments for drug penetration inside the tumour while considering each cell as an individual entity. The impact of these factors on tumour morphology is also showed to see the drug behaviour inside animals/humans tumours. We maintained the heterogeneity factors in presented model as observed in real tumour mass es-pecially in terms of cells proliferation, cell movement, extracellular matrix (ECM) interaction, and the gradients of partial oxygen pressure (pO2) inside tumour cells during the whole growth and treatment activity. The results suggest that TPZ high concentration in combination with chemotherapy should be given to get maximum abnormal cell killing. This model can be a good choice for oncologists and re-searchers to explore more about TPZ action inside solid tumour
New Black Hole Solutions in Brans-Dicke Theory of Gravity
Existence check of non-trivial, stationary axisymmetric black hole solutions
in Brans-Dicke theory of gravity in different direction from those of Penrose,
Thorne and Dykla, and Hawking is performed. Namely, working directly with the
known explicit spacetime solutions in Brans-Dicke theory, it is found that
non-trivial Kerr-Newman-type black hole solutions different from general
relativistic solutions could occur for the generic Brans-Dicke parameter values
-5/2\leq \omega <-3/2. Finally, issues like whether these new black holes carry
scalar hair and can really arise in nature and if they can, what the associated
physical implications would be are discussed carefully.Comment: 20 pages, no figure, Revtex, version to appear in Phys. Rev.
Quantum effects on the BKT phase transition of two-dimensional Josephson arrays
The phase diagram of two dimensional Josephson arrays is studied by means of
the mapping to the quantum XY model. The quantum effects onto the
thermodynamics of the system can be evaluated with quantitative accuracy by a
semiclassical method, the {\em pure-quantum self-consistent harmonic
approximation}, and those of dissipation can be included in the same framework
by the Caldeira-Leggett model. Within this scheme, the critical temperature of
the superconductor-to-insulator transition, which is a
Berezinskii-Kosterlitz-Thouless one, can be calculated in an extremely easy way
as a function of the quantum coupling and of the dissipation mechanism.
Previous quantum Monte Carlo results for the same model appear to be rather
inaccurate, while the comparison with experimental data leads to conclude that
the commonly assumed model is not suitable to describe in detail the real
system.Comment: 4 pages, 2 figures, to be published in Phys. Rev.
Noncommutative QCD, first-order-in-theta-deformed instantons and 't Hooft vertices
For commutative Euclidean time, we study the existence of field
configurations that {\it a)} are formal power series expansions in
h\theta^{\m\n}, {\it b)} go to ordinary (anti-)instantons as
h\theta^{\m\n}\to 0, and {\it c)} render stationary the classical action of
Euclidean noncommutative SU(3) Yang-Mills theory. We show that the
noncommutative (anti-)self-duality equations have no solutions of this type at
any order in h\theta^{\m\n}. However, we obtain all the deformations --called
first-order-in--deformed instantons-- of the ordinary instanton that,
at first order in h\theta^{\m\n}, satisfy the equations of motion of
Euclidean noncommutative SU(3) Yang-Mills theory. We analyze the quantum
effects that these field configurations give rise to in noncommutative SU(3)
with one, two and three nearly massless flavours and compute the corresponding
't Hooft vertices, also, at first order in h\theta^{\m\n}. Other issues
analyzed in this paper are the existence at higher orders in h\theta^{\m\n}
of topologically nontrivial solutions of the type mentioned above and the
classification of the classical vacua of noncommutative SU(N) Yang-Mills theory
that are power series in h\theta^{\m\n}.Comment: Latex. Some macros. No figures. 42 pages. Typos correcte
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