ABSTRACT
We present the results from the first two years of the Planet Hunters TESS (PHT) citizen science project, which identifies planet candidates in the TESS (Transiting Exoplanet Survey ...Satellite) data by engaging members of the general public. Over 22 000 citizen scientists from around the world visually inspected the first 26 sectors of TESS data in order to help identify transit-like signals. We use a clustering algorithm to combine these classifications into a ranked list of events for each sector, the top 500 of which are then visually vetted by the science team. We assess the detection efficiency of this methodology by comparing our results to the list of TESS Objects of Interest (TOIs) and show that we recover 85 per cent of the TOIs with radii greater than 4 R⊕ and 51 per cent of those with radii between 3 and 4 R⊕. Additionally, we present our 90 most promising planet candidates that had not previously been identified by other teams, 73 of which exhibit only a single-transit event in the TESS light curve, and outline our efforts to follow these candidates up using ground-based observatories. Finally, we present noteworthy stellar systems that were identified through the Planet Hunters TESS project.
Random Subspace Ensembles for fMRI Classification Kuncheva, L.I.; Rodriguez, J.J.; Plumpton, C.O. ...
IEEE transactions on medical imaging,
2010-Feb., 2010-Feb, 2010-02-00, 20100201, Letnik:
29, Številka:
2
Journal Article
Classification of brain images obtained through functional magnetic resonance imaging (fMRI) poses a serious challenge to pattern recognition and machine learning due to the extremely large ...feature-to-instance ratio. This calls for revision and adaptation of the current state-of-the-art classification methods. We investigate the suitability of the random subspace (RS) ensemble method for fMRI classification. RS samples from the original feature set and builds one (base) classifier on each subset. The ensemble assigns a class label by either majority voting or averaging of output probabilities. Looking for guidelines for setting the two parameters of the method-ensemble size and feature sample size-we introduce three criteria calculated through these parameters: usability of the selected feature sets, coverage of the set of ¿important¿ features, and feature set diversity. Optimized together, these criteria work toward producing accurate and diverse individual classifiers. RS was tested on three fMRI datasets from single-subject experiments: the Haxby data (Haxby, 2001.) and two datasets collected in-house. We found that RS with support vector machines (SVM) as the base classifier outperformed single classifiers as well as some of the most widely used classifier ensembles such as bagging, AdaBoost, random forest, and rotation forest. The closest rivals were the single SVM and bagging of SVM classifiers. We use kappa-error diagrams to understand the success of RS.
Summary
In contrast to animals, the life cycle of higher plants alternates between a gamete‐producing (gametophyte) and a spore‐producing (sporophyte) generation. The female gametophyte of ...angiosperms consists of four distinct cell types, including two gametes, the egg and the central cell, which give rise to embryo and endosperm, respectively. Based on a combined subtractive hybridization and virtual subtraction approach in wheat (Triticum aestivum L.), we have isolated a class of transcription factors not found in animal genomes, the RKD (RWP‐RK domain‐containing) factors, which share a highly conserved RWP‐RK domain. Single‐cell RT‐PCR revealed that the genes TaRKD1 and TaRKD2 are preferentially expressed in the egg cell of wheat. The Arabidopsis genome contains five RKD genes, at least two of them, AtRKD1 and AtRKD2, are preferentially expressed in the egg cell of Arabidopsis. Ectopic expression of the AtRKD1 and AtRKD2 genes induces cell proliferation and the expression of an egg cell marker. Analyses of RKD‐induced proliferating cells exhibit a shift of gene expression towards an egg cell‐like transcriptome. Promoters of selected RKD‐induced genes were shown to be predominantly active in the egg cell and can be activated by RKD in a transient protoplast expression assay. The data show that egg cell‐specific RKD factors control a transcriptional program, which is characteristic for plant egg cells.
This roadmap on Nanotechnology for Catalysis and Solar Energy Conversion focuses on the application of nanotechnology in addressing the current challenges of energy conversion: 'high efficiency, ...stability, safety, and the potential for low-cost/scalable manufacturing' to quote from the contributed article by Nathan Lewis. This roadmap focuses on solar-to-fuel conversion, solar water splitting, solar photovoltaics and bio-catalysis. It includes dye-sensitized solar cells (DSSCs), perovskite solar cells, and organic photovoltaics. Smart engineering of colloidal quantum materials and nanostructured electrodes will improve solar-to-fuel conversion efficiency, as described in the articles by Waiskopf and Banin and Meyer. Semiconductor nanoparticles will also improve solar energy conversion efficiency, as discussed by Boschloo et al in their article on DSSCs. Perovskite solar cells have advanced rapidly in recent years, including new ideas on 2D and 3D hybrid halide perovskites, as described by Spanopoulos et al 'Next generation' solar cells using multiple exciton generation (MEG) from hot carriers, described in the article by Nozik and Beard, could lead to remarkable improvement in photovoltaic efficiency by using quantization effects in semiconductor nanostructures (quantum dots, wires or wells). These challenges will not be met without simultaneous improvement in nanoscale characterization methods. Terahertz spectroscopy, discussed in the article by Milot et al is one example of a method that is overcoming the difficulties associated with nanoscale materials characterization by avoiding electrical contacts to nanoparticles, allowing characterization during device operation, and enabling characterization of a single nanoparticle. Besides experimental advances, computational science is also meeting the challenges of nanomaterials synthesis. The article by Kohlstedt and Schatz discusses the computational frameworks being used to predict structure-property relationships in materials and devices, including machine learning methods, with an emphasis on organic photovoltaics. The contribution by Megarity and Armstrong presents the 'electrochemical leaf' for improvements in electrochemistry and beyond. In addition, biohybrid approaches can take advantage of efficient and specific enzyme catalysts. These articles present the nanoscience and technology at the forefront of renewable energy development that will have significant benefits to society.
Real-time functional magnetic resonance imaging (fMRI) affords the opportunity to explore the feasibility of self-regulation of functional brain networks through neurofeedback. We localised emotion ...networks individually in thirteen participants using fMRI and trained them to upregulate target areas, including the insula and amygdala. Participants achieved a high degree of control of these networks after a brief training period. We observed activation increases during periods of upregulation of emotion networks in the precuneus and medial prefrontal cortex and, with increasing training success, in the ventral striatum. These findings demonstrate the feasibility of fMRI-based neurofeedback of emotion networks and suggest a possible development into a therapeutic tool.
Changes in seasonal climate patterns and decreasing sea ice cover have facilitated an increase in navigable waters throughout Arctic Canada and resulted in the urgent need for new approaches to ...ocean, coastal, and vessel management. Increased access has resulted in a significant expansion of Arctic shipping activity over the past decade with one of the fastest growing sectors being expedition cruising. This paper presents an assessment of the existing marine regulations and governance structures that manage the cruise sector in Arctic Canada and provides a critical evaluation of its effectiveness considering recent and rapid growth. Using a variety of sources, including interviews with community residents and key informant stakeholders, analysis of changing ship volumes over the past decade, and an inventory of institutional governance for the sector, the major governance challenges for the industry were identified. Also identified are potential strategies for mitigating these challenges. Results of the analysis raise concerns that there is no central authority to govern the growth of the industry, no specific sector or operator management plan, and no site guidelines for highly visited shore locations (other than in protected areas). Instead, governance occurs within the complex multi-jurisdictional regulatory frameworks that exist for all shipping in the region. The paper concludes that under current conditions there are significant barriers to supporting development of this sector while avoiding human, environmental and security problems in the near-to medium-term future.
•The cruise industry in Arctic Canada has grown by over 115% between 2005 and 2013.•Climate change and a reduction of sea ice have increased accessibility to the region.•Many governance challenges exist in managing cruise industry development.•Potential strategies to address current governance challenges are outlined.
We report on 2.4 yr of radio timing measurements of the magnetar PSR J1622−4950 using the Parkes Observatory, between 2011 November and 2014 March. During this period the torque on the neutron star ...(inferred from the rotational frequency derivative) varied greatly, though much less erratically than during the 2 yr following its discovery in 2009. During the last year of our measurements the frequency derivative decreased in magnitude monotonically by 20%, to a value of −1.3 × 10−13 s−2, a factor of 8 smaller than when it was discovered. The flux density continued to vary greatly during our monitoring through 2014 March, reaching a relatively steady low level after late 2012. The pulse profile varied secularly on a similar timescale as the flux density and torque. A relatively rapid transition in all three properties was evident in early 2013. After PSR J1622−4950 was detected in all of our 87 observations up to 2014 March, we did not detect the magnetar in our resumed monitoring starting in 2015 January and have not detected it in any of the 30 observations conducted through 2016 September.
Chemotherapy has improved survival rates in patients with many of the common cancers. However, there is reliable evidence that, as a result of treatment, a subset of cancer survivors experience ...cognitive problems that can last for many years after the completion of chemotherapy. The etiology of this phenomenon is largely unknown, and currently there are no proven treatments. This article explores the clinical and preclinical literature on potential therapies for chemotherapy‐induced cognitive impairments. Emerging results suggest that both pharmacological and behavioral approaches may offer patients some benefits. However, research in this area has been limited and is sometimes fraught with methodological flaws. As a result, it is difficult to draw definite conclusions regarding treatment efficacy. These issues, along with predictors of cognitive decline, are discussed in the light of possible interventions.
Clinical Pharmacology & Therapeutics (2011) 90 3, 366–376. doi:10.1038/clpt.2011.112
Summary
Background Obesity is a significant risk factor for psoriasis and body mass index (BMI) correlates with disease severity.
Objectives To investigate the relationship between obesity and ...psoriasis, focusing on the role of adipokines such as leptin and resistin.
Patients/methods Patients with psoriasis (n = 30) were recruited and their BMI, waist circumference and disease severity Psoriasis Area and Severity Index (PASI) were recorded. Fasting serum samples were obtained on enrolment and after a course of ultraviolet (UV) B treatment. Age‐, sex‐ and BMI‐matched healthy controls were also recruited.
Results On enrolment, serum leptin and soluble leptin receptor levels were not raised compared with the controls. However, resistin, interleukin (IL)‐1β, IL‐6, and chemokines CCL2, CXCL8 and CXCL9 were all significantly elevated in the patient group and serum resistin correlated with disease severity (r = 0·372, P = 0·043). Improvement after UVB treatment was accompanied by decreased serum CXCL8. In vitro, both leptin and resistin could induce CXCL8 and tumour necrosis factor‐α production by blood monocytes, and leptin could additionally induce IL‐1β and IL‐1 receptor antagonist production. Leptin also dose dependently increased secretion of the growth factor amphiregulin by ex vivo‐cultured lesional psoriasis skin.
Conclusions These data support the view that leptin and resistin may be involved in the pathogenesis of psoriasis in overweight individuals, possibly by augmenting the cytokine expression by the inflammatory infiltrate.
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