206 research outputs found
Query-Focused Video Summarization: Dataset, Evaluation, and A Memory Network Based Approach
Recent years have witnessed a resurgence of interest in video summarization.
However, one of the main obstacles to the research on video summarization is
the user subjectivity - users have various preferences over the summaries. The
subjectiveness causes at least two problems. First, no single video summarizer
fits all users unless it interacts with and adapts to the individual users.
Second, it is very challenging to evaluate the performance of a video
summarizer.
To tackle the first problem, we explore the recently proposed query-focused
video summarization which introduces user preferences in the form of text
queries about the video into the summarization process. We propose a memory
network parameterized sequential determinantal point process in order to attend
the user query onto different video frames and shots. To address the second
challenge, we contend that a good evaluation metric for video summarization
should focus on the semantic information that humans can perceive rather than
the visual features or temporal overlaps. To this end, we collect dense
per-video-shot concept annotations, compile a new dataset, and suggest an
efficient evaluation method defined upon the concept annotations. We conduct
extensive experiments contrasting our video summarizer to existing ones and
present detailed analyses about the dataset and the new evaluation method
The structural and functional integrity of peripheral nerves depends on the glial-derived signal desert hedgehog
We show that desert hedgehog ( dhh), a signaling molecule expressed by Schwann cells, is essential for the structural and functional integrity of the peripheral nerve. Dhh-null nerves display multiple abnormalities that affect myelinating and nonmyelinating Schwann cells, axons, and vasculature and immune cells. Myelinated fibers of these mice have a significantly increased ( more than two times) number of Schmidt-Lanterman incisures ( SLIs), and connexin 29, a molecular component of SLIs, is strongly upregulated. Crossing dhh-null mice with myelin basic protein ( MBP)-deficient shiverer mice, which also have increased SLI numbers, results in further increased SLIs, suggesting that Dhh and MBP control SLIs by different mechanisms. Unmyelinated fibers are also affected, containing many fewer axons per Schwann cell in transverse profiles, whereas the total number of unmyelinated axons is reduced by approximately one-third. In dhh-null mice, the blood-nerve barrier is permeable and neutrophils and macrophage numbers are elevated, even in uninjured nerves. Dhh-null nerves also lack the largest-diameter myelinated fibers, have elevated numbers of degenerating myelinated axons, and contain regenerating fibers. Transected dhh nerves degenerate faster than wild-type controls. This demonstrates that a single identified glial signal, Dhh, plays a critical role in controlling the integrity of peripheral nervous tissue, in line with its critical role in nerve sheath development ( Parmantier et al., 1999). The complexity of the defects raises a number of important questions about the Dhh-dependent cell-cell signaling network in peripheral nerves
The cut-off point of dual energy X-ray and laser (DXL) of calcaneus osteoporosis diagnosis in postmenopausal women
Background: Dual X-Ray Absorptiometry (DXA) is a method which can extensively be used for bone mineral densitometry (BMD). Another more recent method is DXL, which associate with dual X ray absorptiometry, assisted by laser measure heel thickness. In this study the cut off points for DXL of calcaneus in the diagnosis of osteoporosis in different bone regions in postmenopausal women had been determined. Materials and Methods: In 268 postmenopausal women, BMD of the spinal and femoral regions was measured by DXA, and the value for the calcaneous was measured by DXL. The agreement of the two methods in the diagnosis of osteoporosis and optimal cut-off point for DXL in defining osteoporosis was obtained. What obtained was the agreement of the two methods in the diagnosis of osteoporosis, as well as the optimal cut-off point for DXL in defining osteoporosis. Results: DXA showed osteoporosis in 40.7 of cases with 35.2 in L2-L4, 16.2 in the femoral neck, and 11.7 for the femoral total region. The DXL found osteoporosis, considering -2.5 SD as a threshold, in 26.1 of cases. Agreement of the two methods in the diagnosis of osteoporosis (Kappa score) was 0.443 for the lumbar region, 0.464 for the neck, and, 0.421 for total femur regions (all P values were significant). Using Receiver Operating Characteristic (ROC ) curves, it was found that a T-score of -2.1, -2.6 and -2.4 as the optimal cut-off point of DXL in the diagnosis of osteoporosis in the lumbar spine, the neck and total region of femur, respectively. Conclusion: The results of this study sh owed a moderate agreement between the two methods in the diagnosis of osteoporosis. It seems that the DXL cannot be used as a substitute for the DXA method, but it can be used as a screening method to find (to diagnose) osteoporosis
A comparison between the novel absorption refrigeration cycle and the conventional ammonia-water absorption refrigeration cycle
Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.One of the recently proposed systems that are capable of reaching to the low temperature of -40 ºC is the novel absorption refrigeration cycle with expander and compressor that works as a co-generation or cooling/power system. This cycle provides better COP than other co-generation low temperature cycles when the refrigerating temperature is low enough. By increasing the evaporation temperature to more than 253 ºC the conventional refrigeration cycle shows better COP and exergetic efficiency in comparison to the novel absorption refrigeration cycle. The purpose of the current study was to analyze the novel absorption refrigeration cycle from the viewpoint of exergy or second law in order to evaluate whether the cycle is practically efficient or not. The exergy destruction rate and the exergetic efficiency for each component were calculated and presented in the corresponding graphs to recognize the components with lower efficiency or higher exergy destruction rate. The influences of an expander in COP and exergetic efficiency were identified by ignoring the expander and super heater from the configuration of the novel absorption refrigeration cycle. Furthermore, energy and exergy balances of a conventional ammonia-water absorption refrigeration cycle were formulated to assess the performance of the system in low and high evaporation temperatures. Our results showed that the novel absorption refrigeration cycle obtains a COP of 0.1109 and exergetic efficiency of 0.1156 when the generation temperature is 360 K and evaporation temperature is 233 K. At the same situation, this cycle without using an expander obtains a COP of 0.0525. In addition, the lowest temperature that can be provided by a conventional refrigeration cycle is 252 K but with a much higher COP. Our results approved that it is possible to choose an absorption refrigeration cycle for a special application without wasting time and consuming extra exergy.cf201
Diabetes management during the COVID-19 pandemic: An Iranian expert opinion statement
The coronavirus infection is an evolving pandemic with high morbidity and mortality, especially in people with comorbidities. The case fatality rate (CFR) is 9.2 in the presence of diabetes, while it is 1.4 in those without any comorbidity. Diabetes is a prevalent disease globally; hence, healthcare professionals are highly concerned about severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic progression. Current evidence does not support higher incidence of coronavirus disease 2019 (COVID-19) in people with diabetes (PWD). However, people with diabetes are considered high risk for developing complications. Optimal metabolic control is a challenging concept, especially in the presence of an acute and severe respiratory viral infection. In this consensus, we considered the challenging issues in management of patients with diabetes during the COVID-19 pandemic. The consensus covers various aspects of outpatient as well as inpatient care based on the current evidence. © 2020 The Author(s)
Epitope Mapping of SERCA2a Identifies an Antigenic Determinant That Induces Mainly Atrial Myocarditis in A/J Mice
Sarcoplasmic/endoplasmic reticulum Ca2+ adenosine triphosphatase (SERCA)2a, a critical regulator of calcium homeostasis, is known to be decreased in heart failure. Patients with myocarditis or dilated cardiomyopathy develop autoantibodies to SERCA2a suggesting that they may have pathogenetic significance. In this report, we describe epitope mapping analysis of SERCA2a in A/J mice that leads us to make five observations: 1) SERCA2a contains multiple T cell epitopes that induce varying degrees of myocarditis. One epitope, SERCA2a 971–990, induces widespread atrial inflammation without affecting noncardiac tissues; the cardiac abnormalities could be noninvasively captured by echocardiography, electrocardiography, and magnetic resonance microscopy imaging. 2) SERCA2a 971–990-induced disease was associated with the induction of CD4 T cell responses and the epitope preferentially binds MHC class II/IAk rather than IEk. By creating IAk/and IEk/SERCA2a 971–990 dextramers, the T cell responses were determined by flow cytometry to be Ag specific. 3) SERCA2a 971–990-sensitized T cells produce both Th1 and Th17 cytokines. 4) Animals immunized with SERCA2a 971–990 showed Ag-specific Abs with enhanced production of IgG2a and IgG2b isotypes, suggesting that SERCA2a 971–990 can potentially act as a common epitope for both T cells and B cells. 5) Finally, SERCA2a 971–990-sensitized T cells were able to transfer disease to naive recipients. Together, these data indicate that SERCA2a is a critical autoantigen in the mediation of atrial inflammation in mice and that our model may be helpful to study the inflammatory events that underlie the development of conditions such as atrial fibrillation in humans
Seroprevalence of cytomegalovirus among women of reproductive age in iran: A systematic review and meta-analysis
Background: Human cytomegalovirus (CMV) able to cause infection for an entire lifetime. This systematic review and meta-analysis was conducted to determine seroprevalence of CMV among women of reproductive age in Iran. Methods: English and Persian databases such as Web of Science (WOS), PubMed, Scopus, Cochrane Library, SID, Iran doc, Iran Medex, Magiran, and Medlib were searched (from 2008 to 2017) accurately using the keywords: Cytomegalovirus, Pregnant women or Pregnancy, Epidemiology, Prevalence and Iran. Results: Results of 15 studies with total samples of 5253 persons from 2008 to 2017 were combined and meta-analyzed. The pooled prevalence rate of IgG among women was estimated 90 (95 CI: 87-93). The highest prevalence rate of IgG was in Tehran, Rasht, Mashhad and Yasoj, all 100 (95 CI: 100-100), and the lowest prevalence was in Jahrom 0.62 (95 CI: 53-71). The overall prevalence rate of IgM among women was estimated at 0.06 (95 CI: 0.03-0.13). The highest prevalence rate of IgM was in Kerman 0.34 (95 CI: 0.29-0.39) and Mashhad 0.25 (95 CI: 0.2-0.31), and the lowest prevalence was in Yasoj 0 (95 CI: 0.00-0.00) Conclusion: The prevalence of immunity in Iran, is satisfactory. Nevertheless, to maintain and increase the level of immunity across the country, it is necessary to routinely screen the women of reproductive ages across the country. © 2019, Iranian Journal of Public Health. All rights reserved
Comparison of MRI findings with traditional criteria in diagnosis of Pendred syndrome
Pendred syndrome, defined as the constellation of goiter, sensori-neural hearing loss, and positive perchlorate discharge test, is the most frequent cause of congenital deafness. Newly introduced diagnostic approaches to the disease are rather expensive and complicated, therefore we evaluated the value of MRI as the sole, or adjunctive diagnostic approach, and compared it with the traditional ones. Presuming the classic triad as the gold standard, we compared MRI findings in six such defined patients with six cases having goiter, hearing loss, and normal perchlorate discharge test. Our results indicated that MRI was 83.6 sensitive and 66.7 specific in patients fulfilling all three criteria (complete), while in the 'partial' group the sensitivity and specificity were 66.7 and 100 respectively. In conclusion, MRI, although impressive as an adjunctive diagnostic tool, may not replace the holistic approach, and the latter may be more convenient, cheaper, and still more accurate. However in 'partial' cases with equivocal findings, and in relatives of the patients, MRI may be a valuable diagnostic adjunct. © 2007 British Society of Audiology, International Society of Audiology, and Nordic Audiological Society
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