21,503 research outputs found

    Bottom water formation and polynyas in Adelie Land, Antarctica

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    Antarctic Bottom Water is the coldest and densest water found in the global ocean. It spreads into all the major ocean basins, carrying the cold water towards the equatorial regions, and is a central component of the global thermo-haline circulation. However, the mechanisms of bottom water formation are not well established; its geographical distribution and rate of formation have yet to be fully quantified. Polynyas, which are large persistent openings in sea-ice that form during the winter near the Antarctic Coast, playa central role in the formation or Antarctic Bottom Water. This paper describes the bottom water formation around the Antarctic continental margin with particular emphasis on the processes and mechanisms of the Adelie Land Bottom Water formation near Dumont D'Urville south of Tasmania

    ActiveStereoNet: End-to-End Self-Supervised Learning for Active Stereo Systems

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    In this paper we present ActiveStereoNet, the first deep learning solution for active stereo systems. Due to the lack of ground truth, our method is fully self-supervised, yet it produces precise depth with a subpixel precision of 1/30th1/30th of a pixel; it does not suffer from the common over-smoothing issues; it preserves the edges; and it explicitly handles occlusions. We introduce a novel reconstruction loss that is more robust to noise and texture-less patches, and is invariant to illumination changes. The proposed loss is optimized using a window-based cost aggregation with an adaptive support weight scheme. This cost aggregation is edge-preserving and smooths the loss function, which is key to allow the network to reach compelling results. Finally we show how the task of predicting invalid regions, such as occlusions, can be trained end-to-end without ground-truth. This component is crucial to reduce blur and particularly improves predictions along depth discontinuities. Extensive quantitatively and qualitatively evaluations on real and synthetic data demonstrate state of the art results in many challenging scenes.Comment: Accepted by ECCV2018, Oral Presentation, Main paper + Supplementary Material

    Investigation of role of cultural spaces to promote level of quality of life in urban spaces (case sample: Sari city)

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    Culture is the root of all changes in past and modern communities, which is the  foundation and base of civilization of the people of each country. Deep cultural  beliefs have a deep role in people's social thought and pave the way of progress for them. The present research has tried to examine methods to improve the quality of cultural spaces in urban spaces. So sample size was estimated 384 people based on Morgan table by using SPSS software, of which males constitutes (45.8%) and females constitutes (54.2%).(86.5%) have mentioned cultural conditions (people'sbeliefs in cultural effects in life,...) and (84.2%) created effects of cultural spaces to fill leisure times of youth, and (84.5%) spatial diversity to attract different age groups by (making space multipurpose) and (51.6%) existence of dynamism and attractiveness by proper lighting both inside and outside the building to more attract people, and (50.5%) personal profile (age, gender and level of education ...) in their responses in order of importance.Most of the citizens (of Sari city) believes in the existence of desirable cultural spaces to promote the quality of urban spaces, and consider it effective in improving urban life according to the results of descriptive findings and binomial test and due to the response of the respondents.Keywords: cultural places, quality of life, culture, urban space

    Non-equilibrium Dynamics of O(N) Nonlinear Sigma models: a Large-N approach

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    We study the time evolution of the mass gap of the O(N) non-linear sigma model in 2+1 dimensions due to a time-dependent coupling in the large-NN limit. Using the Schwinger-Keldysh approach, we derive a set of equations at large NN which determine the time dependent gap in terms of the coupling. These equations lead to a criterion for the breakdown of adiabaticity for slow variation of the coupling leading to a Kibble-Zurek scaling law. We describe a self-consistent numerical procedure to solve these large-NN equations and provide explicit numerical solutions for a coupling which starts deep in the gapped phase at early times and approaches the zero temperature equilibrium critical point gcg_c in a linear fashion. We demonstrate that for such a protocol there is a value of the coupling g=gcdyn>gcg= g_c^{\rm dyn}> g_c where the gap function vanishes, possibly indicating a dynamical instability. We study the dependence of gcdyng_c^{\rm dyn} on both the rate of change of the coupling and the initial temperature. We also verify, by studying the evolution of the mass gap subsequent to a sudden change in gg, that the model does not display thermalization within a finite time interval t0t_0 and discuss the implications of this observation for its conjectured gravitational dual as a higher spin theory in AdS4AdS_4.Comment: 22 pages, 9 figures. Typos corrected, references rearranged and added.v3 : sections rearranged, abstract modified, comment about Kibble-Zurek scaling correcte

    Reconstruction of plasma density profiles by measuring spectra of radiation emitted from oscillating plasma dipoles

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    We suggest a new method for characterising non-uniform density distributions of plasma by measuring the spectra of radiation emitted from a localised plasma dipole oscillator excited by colliding electromagnetic pulses. The density distribution can be determined by scanning the collision point in space. Two-dimensional particle-in-cell simulations demonstrate the reconstruction of linear and nonlinear density profiles corresponding to laser-produced plasma. The method can be applied to a wide range of plasma, including fusion and low temperature plasmas. It overcomes many of the disadvantages of existing methods that only yield average densities along the path of probe pulses, such as interferometry and spectroscopy

    Beneficial Role of Hydro-alcoholic Seed Extract of Trigonella foenum graecum on Bone Structure and Strength in Menopause Induced Osteopenia

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    BACKGROUND: The current strategies to prevent and treat menopausal osteoporosis are hormone replacement therapy (HRT). However, the long-term use of hormone replacement therapy is limited due to its side-effects. Alternately, use of phytoestrogens has been implicated. Trigonella foenum graecum (TFG) seeds are rich in phytoestrogen and known traditional medicine to treat menopause induced hyperlipidemia. Therefore, in this study, we evaluated the role of dietary TFG seed extract on bone structure and mechanical properties in ovariectomized rats.METHODS: Twenty four female Wistar rats were randomly allocated into four groups; 1) control, 2) ovariectomized, 3) ovariectomized + TFG seed extract and 4) ovariectomized + 17β-estradiol. TFG seed extract/17β-estradiol was administered for 30 days, 14 days after ovariectomy. After the treatment, right femora were collected to measure the length and biomechanical properties, and left femora were gathered to study the micro architectural changes while tibia were collected to measure the dry weight.RESULTS: Maximum flexor load to break femur bone was significantly low in ovariectomized rats in comparison with control rats (P<0.05). Supplementation with TFG significantly improved the maximum flexor load (P<0.05) and tibia dry weight (P<0.01) compared to ovariectomized untreated rats. TFG administration also significantly preserved the trabecular (P<0.01) and cortical bone (P<0.05) thickness compared to ovariectomized rats.CONCLUSION: This study found that dietary intake of TFG seeds can improve the bone structure and biomechanical properties in ovariectomized rats indicating that TFG may be an alternative treatment strategy to prevent the menopause induced osteopenia.

    Characterization of basal pseudopod-like processes in ileal and colonic PYY cells.

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    The peptide tyrosine tyrosine (PYY) is produced and secreted from L cells of the gastrointestinal mucosa. To study the anatomy and function of PYY-secreting L cells, we developed a transgenic PYY-green fluorescent protein mouse model. PYY-containing cells exhibited green fluorescence under UV light and were immunoreactive to antibodies against PYY and GLP-1 (glucagon-like peptide-1, an incretin hormone also secreted by L cells). PYY-GFP cells from 15 μm thick sections were imaged using confocal laser scanning microscopy and three-dimensionally (3D) reconstructed. Results revealed unique details of the anatomical differences between ileal and colonic PYY-GFP cells. In ileal villi, the apical portion of PYY cells makes minimal contact with the lumen of the gut. Long pseudopod-like basal processes extend from these cells and form an interface between the mucosal epithelium and the lamina propria. Some basal processes are up to 50 μm in length. Multiple processes can be seen protruding from one cell and these often have a terminus resembling a synapse that appears to interact with neighboring cells. In colonic crypts, PYY-GFP cells adopt a spindle-like shape and weave in between epithelial cells, while maintaining contact with the lumen and lamina propria. In both tissues, cytoplasmic granules containing the hormones PYY and GLP-1 are confined to the base of the cell, often filling the basal process. The anatomical arrangement of these structures suggests a dual function as a dock for receptors to survey absorbed nutrients and as a launching platform for hormone secretion in a paracrine fashion

    Protobacco Media Exposure and Youth Susceptibility to Smoking Cigarettes, Cigarette Experimentation, and Current Tobacco Use among US Youth

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    Purpose: Youth are exposed to many types of protobacco influences, including smoking in movies, which has been shown to cause initiation. This study investigates associations between different channels of protobacco media and susceptibility to smoking cigarettes, cigarette experimentation, and current tobacco use among US middle and high school students. Methods: By using data from the 2012 National Youth Tobacco Survey, structural equation modeling was performed in 2013. The analyses examined exposure to tobacco use in different channels of protobacco media on smoking susceptibility, experimentation, and current tobacco use, accounting for perceived peer tobacco use. Results: In 2012, 27.9% of respondents were never-smokers who reported being susceptible to trying cigarette smoking. Cigarette experimentation increased from 6.3% in 6th grade to 37.1% in 12th grade. Likewise, current tobacco use increased from 5.2% in 6th grade to 33.2% in 12th grade. Structural equation modeling supported a model in which current tobacco use is associated with exposure to static advertising through perception of peer use, and by exposure to tobacco use depicted on TV and in movies, both directly and through perception of peer use. Exposure to static advertising appears to directly increase smoking susceptibility but indirectly (through increased perceptions of peer use) to increase cigarette experimentation. Models that explicitly incorporate peer use as a mediator can better discern the direct and indirect effects of exposure to static advertising on youth tobacco use initiation.Conclusions: These findings underscore the importance of reducing youth exposure to smoking in TV, movies, and static advertising

    ADHD: Is There an App for That? A Suitability Assessment of Apps for the Parents of Children and Young People With ADHD

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    BACKGROUND: Attention-deficit hyperactivity disorder (ADHD) is a highly comorbid disorder that can impact significantly on the individual and their family. ADHD is managed via pharmacological and nonpharmacological interventions. Parents also gain support from parent support groups, which may include chat rooms, as well as face-to-face meetings. With the growth of technology use over recent years, parents have access to more resources that ever before. A number of mobile apps have been developed to help parents manage ADHD in their children and young people. Unfortunately many of these apps are not evidence-based, and little is known of their suitability for the parents or whether they are helpful in ADHD management. OBJECTIVE: The aim of this study was to explore the (1) parents' views of the suitability of the top ten listed apps for parents of children and young people with ADHD and (2) the views of clinicians that work with them on the suitability and value of the apps. METHODS: The top 10 listed apps specifically targeted toward the parents of children and young people with ADHD were identified via the Google Play (n=5) and iTunes store (n=5). Interviews were then undertaken with 7 parents of children or young people with ADHD and 6 clinicians who specialize in working with this population to explore their opinions of the 10 apps identified and what they believe the key components are for apps to be suitable and valuable for this population. RESULTS: Four themes emerged from clinician and parent interviews: (1) the importance of relating to the app, (2) apps that address ADHD-related difficulties, (3) how the apps can affect family relationships, and (4) apps as an educational tool. Two additional themes emerged from the clinician interviews alone: monitoring ADHD symptoms and that apps should be practical. Parents also identified an additional theme: the importance of the technology. Overall, the characteristics of the current top 10 listed apps did not appear to match well to the views of our sample. CONCLUSIONS: Findings suggest that these apps may not fully meet the complex needs of this parent population. Further research is required to explore the value of apps with this population and how they can be tailored to their very specific needs
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