422 research outputs found
J Regularization Improves Imbalanced Multiclass Segmentation
We propose a new loss formulation to further advance the multiclass segmentation of cluttered cells under weakly supervised conditions. When adding a Youden's J statistic regularization term to the cross entropy loss we improve the separation of touching and immediate cells, obtaining sharp segmentation boundaries with high adequacy. This regularization intrinsically supports class imbalance thus eliminating the necessity of explicitly using weights to balance training. Simulations demonstrate this capability and show how the regularization leads to correct results by helping advancing the optimization when cross entropy stagnates. We build upon our previous work on multiclass segmentation by adding yet another training class representing gaps between adjacent cells. This addition helps the classifier identify narrow gaps as background and no longer as touching regions. We present results of our methods for 2D and 3D images, from bright field images to confocal stacks containing different types of cells, and we show that they accurately segment individual cells after training with a limited number of images, some of which are poorly annotated
Arctic air pollution: Challenges and opportunities for the next decade
The Arctic is a sentinel of global change. This region is influenced by multiple physical and socio-economic drivers and feedbacks, impacting both the natural and human environment. Air pollution is one such driver that impacts Arctic climate change, ecosystems and health but significant uncertainties still surround quantification of these effects. Arctic air pollution includes harmful trace gases (e.g. tropospheric ozone) and particles (e.g. black carbon, sulphate) and toxic substances (e.g. polycyclic aromatic hydrocarbons) that can be transported to the Arctic from emission sources located far outside the region, or emitted within the Arctic from activities including shipping, power production, and other industrial activities. This paper qualitatively summarizes the complex science issues motivating the creation of a new international initiative, PACES (air Pollution in the Arctic: Climate, Environment and Societies). Approaches for coordinated, international and interdisciplinary research on this topic are described with the goal to improve predictive capability via new understanding about sources, processes, feedbacks and impacts of Arctic air pollution. Overarching research actions are outlined, in which we describe our recommendations for 1) the development of trans-disciplinary approaches combining social and economic research with investigation of the chemical and physical aspects of Arctic air pollution; 2) increasing the quality and quantity of observations in the Arctic using long-term monitoring and intensive field studies, both at the surface and throughout the troposphere; and 3) developing improved predictive capability across a range of spatial and temporal scales
Non-Abelian Vortices on the Torus
We study periodic arrays of non-Abelian vortices in an
gauge theory with flavors of fundamental matter multiplets. We carefully
discuss the corresponding twisted boundary conditions on the torus and propose
an ansatz to solve the first order Bogomolnyi equations which we find by
looking to a bound of the energy. We solve the equations numerically and
construct explicit vortex solutions
J Regularization Improves Imbalanced Multiclass Segmentation
We propose a new loss formulation to further advance the multiclass segmentation of cluttered cells under weakly supervised conditions. When adding a Youden's J statistic regularization term to the cross entropy loss we improve the separation of touching and immediate cells, obtaining sharp segmentation boundaries with high adequacy. This regularization intrinsically supports class imbalance thus eliminating the necessity of explicitly using weights to balance training. Simulations demonstrate this capability and show how the regularization leads to correct results by helping advancing the optimization when cross entropy stagnates. We build upon our previous work on multiclass segmentation by adding yet another training class representing gaps between adjacent cells. This addition helps the classifier identify narrow gaps as background and no longer as touching regions. We present results of our methods for 2D and 3D images, from bright field images to confocal stacks containing different types of cells, and we show that they accurately segment individual cells after training with a limited number of images, some of which are poorly annotated
The effects of genetic and modifiable risk factors on brain regions vulnerable to ageing and disease
We have previously identified a network of higher-order brain regions particularly vulnerable to the ageing process, schizophrenia and Alzheimer's disease. However, it remains unknown what the genetic influences on this fragile brain network are, and whether it can be altered by the most common modifiable risk factors for dementia. Here, in ~40,000 UK Biobank participants, we first show significant genome-wide associations between this brain network and seven genetic clusters implicated in cardiovascular deaths, schizophrenia, Alzheimer's and Parkinson's disease, and with the two antigens of the XG blood group located in the pseudoautosomal region of the sex chromosomes. We further reveal that the most deleterious modifiable risk factors for this vulnerable brain network are diabetes, nitrogen dioxide - a proxy for traffic-related air pollution - and alcohol intake frequency. The extent of these associations was uncovered by examining these modifiable risk factors in a single model to assess the unique contribution of each on the vulnerable brain network, above and beyond the dominating effects of age and sex. These results provide a comprehensive picture of the role played by genetic and modifiable risk factors on these fragile parts of the brain
Th17 Cells and IL-17 in Protective Immunity to Vaginal Candidiasis
Background: Th17 cells play a major role in coordinating the host defence in oropharyngeal candidiasis. In this study we investigated the involvement of the Th17 response in an animal model of vulvovaginal candidiasis (VVC). Methods: To monitor the course of infection we exploited a new in vivo imaging technique. Results: i) The progression of VVC leads to a strong influx of neutrophils in the vagina soon after the challenge which persisted despite the resolution of infection; ii) IL-17, produced by vaginal cells, particularly CD4 T cells, was detected in the vaginal wash during the infection, reaching a maximum 14 days after the challenge; iii) The amount and kinetics of IL-23 in vaginal fluids were comparable to those in vaginal cells; iv) The inhibition of Th17 differentiation led to significant inhibition of IL-17 production with consequent exacerbation of infection; v) An increased production of bdefensin 2 was manifested in cells of infected mice. This production was strongly reduced when Th17 differentiation was inhibited and was increased by rIL-17 treatment. Conclusions: These results imply that IL-17 and Th17, along with innate antimicrobial factors, have a role in the immune response to vaginal candidiasis
Assessment of vitamin D status and parathyroid hormone during a combined intervention for the treatment of childhood obesity
Background: Obesity is associated with vitamin D deficiency. The aim of this work is to analyze the changes in vitamin
D status and PTH levels in a group of children with obesity receiving combined intervention program in order to get
BMI status reduction.
Methods: Longitudinal study in 119 children with obesity, aged 9.1–13.9 years, included in a 1-year combined dietarybehavioral-physical activity intervention. Anthropometric measurements (weight, height, BMI and fat mass index) were
registered every 3 months and blood testing (calcium, phosphorous, 25(OH)D and PTH) were collected at the
beginning and after 12 months of follow-up. A control group was recruited (300 healthy children, aged 8.1–13.9 years).
The criteria of the US Endocrine Society were used for the definition of hypovitaminosis D.
Results: Vitamin D deficiency was significantly higher in obesity group (31.1 vs. 14%). There was negative correlation
between 25(OH)D and fat mass index (r = −0.361, p = 0.001). Patients with BMI reduction throughout combined
intervention were 52 (43.7%). There was a significant increase in the prevalence of hypovitaminosis D in patients
without BMI reduction at the end of follow-up, but in those patients with BMI reduction there was no changes of
vitamin D status.
Conclusions: Obesity increases the prevalence of suboptimal vitamin D status, and a BMI status reduction in children
with obesity may be required to at least stabilize vitamin D status
Hypovitaminosis D and cardiometabolic risk factors in adolescents with severe obesity
Background/Objectives. Obesity is associated with cardiometabolic risk factors and with
Vitamin D deficiency. The aim of this study was to examine the relationship between 25(OH)D
concentrations and cardiometabolic risk factors in adolescents with severe obesity. Subjects/Methods.
A cross-sectional clinical assessment (body mass index, fat mass index, fat-free mass index,
waist-to-height ratio, and blood pressure) and metabolic study (triglycerides, total cholesterol,
HDL-C, LDL-C, glucose, insulin, HOMA-IR, leptin, calcium, phosphorous, calcidiol, and PTH) were
carried out in 236 adolescents diagnosed with severe obesity (BMI z-score > 3.0, 99th percentile), aged
10.2–15.8 years. The criteria of the US Endocrine Society were used for the definition of Vitamin D
status. Results. Subjects with Vitamin D deficiency had significantly elevated values (p < 0.05) for BMI
z-score, waist circumference, waist z-score, body fat percentage, fat mass index, systolic and diastolic
blood pressure, total cholesterol, triglycerides, LDL-C, insulin, HOMA-IR, leptin, and PTH than
subjects with normal Vitamin D status. There was a significant negative correlation (p < 0.05) of serum
25(OH)D levels with body fat percentage, FMI, systolic BP, total cholesterol, triglyceride, LDL-C,
glucose, insulin, HOMA-IR, leptin, and PTH. Conclusions. Low Vitamin D levels in adolescents with
severe obesity were significantly associated with some cardiometabolic risk factors, including body
mass index, waist circumference, fat mass index, high blood pressure, impaired lipid profile, and
insulin resistance
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On Birthing Dancing Stars: The Need for Bounded Chaos in Information Interaction
While computers causing chaos is acommon social trope, nearly the entirety of the history of computing is dedicated to generating order. Typical interactive information retrieval tasks ask computers to support the traversal and exploration of large, complex information spaces. The implicit assumption is that they are to support users in simplifying the complexity (i.e. in creating order from chaos). But for some types of task, particularly those that involve the creative application or synthesis of knowledge or the creation of new knowledge, this assumption may be incorrect. It is increasingly evident that perfect order—and the systems we create with it—support highly-structured information tasks well, but provide poor support for less-structured tasks.We need digital information environments that help create a little more chaos from order to spark creative thinking and knowledge creation. This paper argues for the need for information systems that offerwhat we term ‘bounded chaos’, and offers research directions that may support the creation of such interface
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