Evolution of galaxy groups in the Illustris simulation

We present the first study of evolution of galaxy groups in the Illustris simulation. We focus on dynamically relaxed and unrelaxed galaxy groups representing dynamically evolved and evolving galaxy systems, respectively. The evolutionary state of a group is probed from its luminosity gap and separation between the brightest group galaxy and the center of mass of the group members. We find that the Illustris simulation, over-produces large luminosity gap galaxy systems, known as fossil systems, in comparison to observations and the probed semi-analytical predictions. However, this simulation is equally successful in recovering the correlation between luminosity gap and luminosity centroid offset, in comparison to the probed semi-analytic model. We find evolutionary tracks based on luminosity gap which indicate that a large luminosity gap group is rooted in a small luminosity gap group, regardless of the position of the brightest group galaxy within the halo. This simulation helps, for the first time, to explore the black hole mass and its accretion rate in galaxy groups. For a given stellar mass of the brightest group galaxies, the black hole mass is larger in dynamically relaxed groups with a lower rate of mass accretion. We find this consistent with the latest observational studies of the radio activities in the brightest group galaxies in fossil groups. We also find that the IGM in dynamically evolved groups is hotter for a given halo mass than that in evolving groups, again consistent with earlier observational studies.Comment: 10 pages, 10 figures. Accepted for publication in Ap

Colourings of cubic graphs inducing isomorphic monochromatic subgraphs

A $k$-bisection of a bridgeless cubic graph $G$ is a $2$-colouring of its vertex set such that the colour classes have the same cardinality and all connected components in the two subgraphs induced by the colour classes (monochromatic components in what follows) have order at most $k$. Ban and Linial conjectured that every bridgeless cubic graph admits a $2$-bisection except for the Petersen graph. A similar problem for the edge set of cubic graphs has been studied: Wormald conjectured that every cubic graph $G$ with $|E(G)| \equiv 0 \pmod 2$ has a $2$-edge colouring such that the two monochromatic subgraphs are isomorphic linear forests (i.e. a forest whose components are paths). Finally, Ando conjectured that every cubic graph admits a bisection such that the two induced monochromatic subgraphs are isomorphic. In this paper, we give a detailed insight into the conjectures of Ban-Linial and Wormald and provide evidence of a strong relation of both of them with Ando's conjecture. Furthermore, we also give computational and theoretical evidence in their support. As a result, we pose some open problems stronger than the above mentioned conjectures. Moreover, we prove Ban-Linial's conjecture for cubic cycle permutation graphs. As a by-product of studying $2$-edge colourings of cubic graphs having linear forests as monochromatic components, we also give a negative answer to a problem posed by Jackson and Wormald about certain decompositions of cubic graphs into linear forests.Comment: 33 pages; submitted for publicatio

Exchange energy and generalized polarization in the presence of spin-orbit coupling in two dimensions

We discuss a general form of the exchange energy for a homogeneous system of interacting electrons in two spatial dimensions which is particularly suited in the presence of a generic spin-orbit interaction. The theory is best formulated in terms of a generalized fractional electronic polarization. Remarkably we find that a net generalized polarization does not necessarily translate into an increase in the magnitude of the exchange energy, a fact that in turn favors unpolarized states. Our results account qualitatively for the findings of recent experimental investigations

Optically selected fossil groups; X-ray observations and galaxy properties

We report on the X-ray and optical observations of galaxy groups selected from the 2dfGRS group catalog, to explore the possibility that galaxy groups hosting a giant elliptical galaxy and a large optical luminosity gap present between the two brightest group galaxies, can be associated with an extended X-ray emission, similar to that observed in fossil galaxy groups. The X-ray observations of 4 galaxy groups were carried out with Chandra telescope with 10-20 ksec exposure time. Combining the X-ray and the optical observations we find evidences for the presence of a diffuse extended X-ray emission beyond the optical size of the brightest group galaxy. Taking both the X-ray and the optical criteria, one of the groups is identified as a fossil group and one is ruled out because of the contamination in the earlier optical selection. For the two remaining systems, the X-ay luminosity threshold is close to the convention know for fossil groups. In all cases the X-ray luminosity is below the expected value from the X-ray selected fossils for a given optical luminosity of the group. A rough estimation for the comoving number density of fossil groups is obtained and found to be in broad agreement with the estimations from observations of X-ray selected fossils and predictions of cosmological simulations.Comment: Accepted for publication in MNRA

Remarkable Presentation: Anaplastic Thyroid Carcinoma Arising from Chronic Hyperthyroidism

Background. Undifferentiated anaplastic carcinoma rarely develops from chronic hyperthyroidism. Although acute hyperthy- roidism can develop prior to anaplastic transformation, chronic hyperthyroidism was thought to be a protective measure against thyroid malignancy. Methods. A 79-year-old female presented acutely to the hospital with dyspnea. She had been taking methimazole for chronic hyperthyroidism due to toxic thyroid nodules, previously biopsied as benign. Upon admission, imaging showed tracheal compression, requiring a total thyroidectomy with tracheostomy for airway management. Results. Pathology demonstrated undifferentiated anaplastic thyroid carcinoma. The patient passed away shortly after hospital discharge. Despite treatment with methimazole for many years, abrupt enlargement of her toxic multinodular goiter was consistent with malignant transformation. Chronic hyperthyroidism and toxic nodules are rarely associated with thyroid malignancy, with only one previous report documenting association with anaplastic thyroid carcinoma. Conclusion. Progressive thyroid enlargement and acute worsening of previously controlled hyperthyroidism should promote concern for disease regardless of baseline thyroid function

Long-Term Effectiveness of Balloon Catheter Sinuplasty in Pediatric Chronic Maxillary Sinusitis

The objective of our study was to assess the long-term effectiveness of balloon catheter sinuplasty in the treatment of pediatric chronic maxillary sinusitis following failed first-line medical and surgical management with adenoidectomy. Pediatric patients younger than 12 years were reviewed for having failed previous adenoidectomy and undergone a balloon catheter sinuplasty between August 2006 and March 2011 for chronic rhinosinusitis. Demographic data and clinical characteristics were recorded in patients who met inclusion criteria. Outcomes were assessed by need for functional endoscopic sinus surgery and persistence of chronic infection within at least 5 years of follow-up. Failure was defined by any child who was rediagnosed with chronic sinus disease after balloon catheter sinuplasty or who required endoscopic sinus surgery within 5 years. Sixty-two children were reviewed, with 38 patients meeting inclusion criteria (prior adenoidectomy, a preoperative Lund-Mackay score of ≥5, and balloon catheter sinuplasty). The mean age (standard deviation) was 6.76 (2.27) years with an age range of 2 to 11 years. Eight children (21.1%, P \u3c .01) continued to have chronic sinus complaints following balloon procedure, with 5 (13.1%) individuals requiring eventual endoscopic surgery within 5 years. Age, asthma, allergy, and gender did not have any statistically significant impact on outcome. Balloon catheter sinuplasty is an effective long-term alternative for the treatment of chronic rhinosinusitis in pediatric patients, hoping to avoid further infections and eventual endoscopic surgery

Impact of biochar and arbuscular mycorrhizal inoculation on root colonization and selected soil chemical properties in south western Nigeria

The use of biochar and arbuscular mycorrhizal fungi (AMF) provide many opportunities for soil improvement, it is, therefore, important to understand their impact on soil and plant development so as to optimally exploit their potentials. Screenhouse experiment was conducted to evaluate the impact of biochar application and arbuscular mycorrhizal (AM) inoculation on root colonization and selected soil chemical properties. The experiment was laid out in a 2×5×2 factorial, fitted into a completely randomized design with three replications. The factors included tomato genotypes (Ex-Lafia and Ex-Lokoja), biochar application rates (0, 5, 10, 15, and 20 t ha-1) and AMF (with and without AMF). Data were subjected to analysis of variance and significant means were separated using Duncan’s Multiple Range Test (p<0.05). The results showed that AM inoculation significantly (p<0.05) increased root colonization (51.33%) when compared with non mycorrhizal plants (10.17%). However, no significant differences were observed in soil pH, organic carbon and available P between mycorrhizal and non mycorrhizal plants. On the other hand, amendment with the 20t ha-1 of biochar recorded significantly (p<0.05) higher values of AM root colonization (46.25%), soil pH (7.05) and available P (13.93 mg kg-1) when compared to other biochar rates though comparable with 15 t ha-1 in soil pH (7.05) and available P (12.26 mg kg-1). It is therefore concluded that AM inoculation in biochar-amended soil improved root colonization while biochar application enhances root colonization, soil pH and available P.Keywords: Biochar, AM inoculation, soil chemical properties

An Assessment of the Wear Element Contamination of Food Processed by Wet Milling Using Atomic Absorption Spectroscopy Technique

This paper ‘Assessment of Wear Elements in Food Products by Wet Milling Using Atomic Absorption Spectroscopy Technique’ was carried out to determine the levels of Wear Elements introduced into food consumed by humans after being wet milled. Samples were collected from a selected milling house in Yelwa area in Bauchi State Nigeria and were analyzed. The presence of heavy metals such as Cadmium (Cd) and Lead (Pb) as well as trace elements; Copper (Cu) and Zinc (Zn) contents in milled beans, tomatoes, sweet pepper and onions were determined using Atomic Absorption Spectrometry. The wear elements detected ranged from 0.008 to 0.017 mgkg?1 of Pb and 12.42 to 17.63 mgkg?1 of Fe and Cd went undetected being lower than the detection limits of 0.003 mgkg1.. However, the trace elements ranged from 6.75 to 11.84 mgkg?1 of Cu and 9.35 to 81.25mgkg?1 of Zn. The highest values of Pb, Cu, Zn and Fe in the milled products were observed in Onion paste (0.017mgkg?1), Tomato slurry (11.84mgkg?1), Beans paste (81.25 mgkg?1) respectively. The level of Fe and Zn in most of the samples was found to be above the permissible level of 15 mgkg?1 and 60 mgkg?1 respectively as set by WHO (2003). Other wear elements were found to be within the safe levels. Keywords: Wear Element, Atomic Absorption Spectroscopy, and Wet Milling