Fredholm theory of Toeplitz operators on standard weighted Fock spaces

We study the Fredholm properties of Toeplitz operators with bounded symbols of vanishing mean oscillation in the complex plane. In particular, we prove that the Toeplitz operator with such a symbol is Fredholm on a standard weighted Fock space if and only if the Berezin transform of the symbol is bounded away from zero outside a sufficiently large disk in the complex plane. We also show that the Fredholm index of the Toeplitz operator can be computed via the winding of the symbol along a sufficiently large circle. We finish by considering Toeplitz operators with matrix-valued symbols

Model Compression Methods for YOLOv5: A Review

Over the past few years, extensive research has been devoted to enhancing YOLO object detectors. Since its introduction, eight major versions of YOLO have been introduced with the purpose of improving its accuracy and efficiency. While the evident merits of YOLO have yielded to its extensive use in many areas, deploying it on resource-limited devices poses challenges. To address this issue, various neural network compression methods have been developed, which fall under three main categories, namely network pruning, quantization, and knowledge distillation. The fruitful outcomes of utilizing model compression methods, such as lowering memory usage and inference time, make them favorable, if not necessary, for deploying large neural networks on hardware-constrained edge devices. In this review paper, our focus is on pruning and quantization due to their comparative modularity. We categorize them and analyze the practical results of applying those methods to YOLOv5. By doing so, we identify gaps in adapting pruning and quantization for compressing YOLOv5, and provide future directions in this area for further exploration. Among several versions of YOLO, we specifically choose YOLOv5 for its excellent trade-off between recency and popularity in literature. This is the first specific review paper that surveys pruning and quantization methods from an implementation point of view on YOLOv5. Our study is also extendable to newer versions of YOLO as implementing them on resource-limited devices poses the same challenges that persist even today. This paper targets those interested in the practical deployment of model compression methods on YOLOv5, and in exploring different compression techniques that can be used for subsequent versions of YOLO.Comment: 18 pages, 7 Figure

Evaluation of quality assurance instruments in higher education institutions: A case of Oman

The use of a variety of instruments for quality assurance, management, and enhancement in higher education is well recognized. This article investigated the instruClose Panelments used by Higher Education Institutions (HEIs) in Oman to measure, control, and manage the quality of their services in alignment with the standards set by Oman Academic Accreditation Authority (OAAA). Quality Assurance Managers (QAMs) from five HEIs were interviewed to identify the instruments used by them to fulfil the requirements of each standard and the way they make use of the data gathered by using these instruments. Findings from the study reveal that questionnaires and meetings are the most common instruments used by these institutions to measure, control and assure the efficacy of their current quality activities. In addition, HEIs use summary statistics to analyse data and then present them in meetings or through reports. On the other hand, it was found that substantial efforts are made to collect data but the efficient usage of data is missing. The QAMs reported a lack of awareness among the staff on the importance of collecting data since the staff members believe that these data are collected for documentation purposes only. This study emphasizes the importance of using the data gathered from different instruments in decision making and enhancing the quality of HEIs

Safety aspects of infliximab in inflammatory bowel disease patients - A retrospective cohort study in 100 patients of a German University Hospital

Background: Infliximab, a chimeric anti-tumour necrosis factor monoclonal antibody with potent anti-inflammatory effects, represents an effective treatment option in patients with severe inflammatory bowel disease (IBD). Serious side-effects of such an immunomodulating therapy are speculated and therefore we reviewed our clinical experience in a retrospective safety study looking upon a single cohort of 100 IBD patients from a large German University Hospital. Methods: 100 patients with severe Crohn's disease (n = 92), ulcerative colitis (n = 7) or indeterminate colitis (n = 1) treated with infliximab (5 mg/kg) from January 2000 to December 2003 were retrospectively analysed for acute and subacute adverse events by chart review. Results: Overall, infliximab therapy was generally well tolerated. No fatal complications, malignancies, autoimmune diseases, neurologic or cardiovascular complications were observed in the cohort during the study period. Overall, adverse events were observed in 10 patients: 2 patients showed an acute infusion reaction, 1 patient a serum sickness-like reaction, in 4 patients a bacterial or viral infection occurred, in 1 patient pancytopenia and 2 patients developed surgical complications. Only 6 patients with adverse events required admission to hospital. A case of tuberculosis after infliximab was not found. The lack of adverse side-effects was associated with young median age and infrequent comorbidities of the cohort. Conclusion: Regarding its strong immunomodulating capacity, infliximab appears to be an efficient and relatively safe therapeutic option for patients with severe IBD. However, the use of infliximab requires careful screening and close patient monitoring to identify patients at risk and the infrequent, but sometimes serious complications of infliximab. Copyright (C) 2004 S. Karger AG, Basel

Fredholm theory of Toeplitz operators on doubling Fock Hilbert spaces

We study the Fredholm properties of Toeplitz operators acting on doubling Fock Hilbert spaces, and describe their essential spectra for bounded symbols of vanishing oscillation. We also compute the index of these Toeplitz operators in the special case when ϕ(z) = |z| β with β > 0. Our work extends the recent results on Toeplitz operators on the standard weighted Fock spaces to the setting of doubling Fock spaces

The effect of maternal position on placental blood flow and fetoplacental oxygenation in late gestation fetal growth restriction: a magnetic resonance imaging study

Fetal growth restriction (FGR) and maternal supine going-to-sleep position are both risk factors for late stillbirth. This study aimed to use magnetic resonance imaging (MRI) to quantify the effect of maternal supine position on maternal-placental and fetoplacental blood flow, placental oxygen transfer and fetal oxygenation in FGR and healthy pregnancies. Twelve women with FGR and 27 women with healthy pregnancies at 34–38 weeks’ gestation underwent MRI in both left lateral and supine positions. Phase-contrast MRI and a functional MRI technique (DECIDE) were used to measure blood flow in the maternal internal iliac arteries (IIAs) and umbilical vein (UV), placental oxygen transfer (placental flux), fetal oxygen saturation (FO2), and fetal oxygen delivery (delivery flux). The presence of FGR, compared to healthy pregnancies, was associated with a 7.8% lower FO2 (P = 0.02), reduced placental flux, and reduced delivery flux. Maternal supine positioning caused a 3.8% reduction in FO2 (P = 0.001), and significant reductions in total IIA flow, placental flux, UV flow and delivery flux compared to maternal left lateral position. The effect of maternal supine position on fetal oxygen delivery was independent of FGR pregnancy, meaning that supine positioning has an additive effect of reducing fetal oxygenation further in women with FGR, compared to women with appropriately grown for age pregnancies. Meanwhile, the effect of maternal supine positioning on placental oxygen transfer was not independent of the effect of FGR. Therefore, growth-restricted fetuses, which are chronically hypoxaemic, experience a relatively greater decline in oxygen transfer when mothers lie supine in late gestation compared to appropriately growing fetuses. (Figure presented.). Key points: Fetal growth restriction (FGR) is the most common risk factor associated with stillbirth, and early recognition and timely delivery is vital to reduce this risk. Maternal supine going-to-sleep position is found to increase the risk of late stillbirth but when combined with having a FGR pregnancy, maternal supine position leads to 15 times greater odds of stillbirth compared to supine sleeping with appropriately grown for age (AGA) pregnancies. Using MRI, this study quantifies the chronic hypoxaemia experienced by growth-restricted fetuses due to 13.5% lower placental oxygen transfer and 26% lower fetal oxygen delivery compared to AGA fetuses. With maternal supine positioning, there is a 23% reduction in maternal-placental blood flow and a further 14% reduction in fetal oxygen delivery for both FGR and AGA pregnancies, but this effect is proportionally greater for growth-restricted fetuses. This knowledge emphasises the importance of avoiding supine positioning in late pregnancy, particularly for vulnerable FGR pregnancies

The effect of distance to health-care facilities on childhood mortality in rural Burkina Faso.

This study aims to investigate the relation between distance to health facilities, measured as continuous travel time, and mortality among infants and children younger than 5 years of age in rural Burkina Faso, an area with low health facility density. The study included 24,555 children born between 1993 and 2005 in the Nouna Health and Demographic Surveillance System. The average walking time from each village to the closest health facility was obtained for both the dry and the rainy season, and its effect on infant (<1 year), child (1-4 years), and under-5 mortality overall was analyzed by Cox regression. The authors observed 3,426 childhood deaths, corresponding to a 5-year survival of 85%. Walking distance was significantly related to both infant and child mortality, although the shape of this effect varied distinctly between the 2 age groups. Overall, under-5 mortality, adjusted for confounding, was more than 50% higher at a distance of 4 hours compared with having a health facility in the village (P < 0.0001, 2 sided). The region of residence was an additional determinant for under-5 mortality. The findings of this study emphasize the importance of geographic accessibility of health care for child survival in sub-Saharan Africa and demonstrate the need to improve health-care access to achieve the Millennium Development Goals

Pyridinethiol-Assisted Dissolution of Elemental Gold in Organic Solutions

Dissolution of elemental gold in organic solutions is a contemporary approach to lower the environmental burden associated with gold recycling. Herein, we describe fundamental studies on a highly efficient method for the dissolution of elemental Au that is based on DMF solutions containing pyridine-4-thiol (4-PSH) as a reactive ligand and hydrogen peroxide as an oxidant. Dissolution of Au proceeds through several elementary steps: isomerization of 4-PSH to pyridine-4-thione (4-PS), coordination with Au-0, and then oxidation of the Au-0 thione species to Au-I simultaneously with oxidation of free pyridine thione to elemental sulfur and further to sulfuric acid. The final dissolution product is a Au-I complex bearing two 4-PS ligands and SO42- as a counterion. The ligand is crucial as it assists the oxidation process and stabilizes and solubilizes the formed Au cations.Peer reviewe