Chick PTPσ regulates the targeting of retinal axons within the optic tectum

Chick PTP (cPTP), also known as CRYP, is a receptor-like protein tyrosine phosphatase found on axons and growth cones. Putative ligands for cPTP are distributed within basement membranes and on glial end feet of the retina, optic nerve, and optic tectum, suggesting that cPTP signaling is occurring along the whole retinotectal pathway. We have shown previously that cPTP plays a role in supporting the retinal phase of axon outgrowth. Here we have now addressed the role of cPTP within retinal axons as they undergo growth and topographic targeting in the optic tectum. With the use of retroviruses, a secretable cPTP ectodomain was ectopically expressed in ovo in the developing chick optic tectum, with the aim of directly disrupting the function of endogenous cPTP. In ovo, the secreted ectodomains accumulated at tectal sites in which cPTP ligands are also specifically found, suggesting that they are binding to these endogenous ligands. Anterograde labeling of retinal axons entering these optic tecta revealed abnormal axonal phenotypes. These included the premature stalling and arborization of fibers,excessive pretectal arbor formation, and diffuse termination zones. Most of the defects were rostral of the predicted termination zone, indicating that cPTP function is necessary for sustaining the growth of retinal axons over the optic tectum and for directing axons to their correct sites of termination. This demonstrates that regulation of cPTP signaling in retinal axons is required for their topographic mapping, the first evidence of this function for a receptor-like protein tyrosine phosphatase in the retinotectal projection

Civil society activism, strategic alignment and international public policy making for spectrum

Recent work in political science asserts a growth in prominence of civil society in international public policy processes, something that has been to this point under-addressed in the field of public policy research in communication. This article undertakes an analysis of the role of civil society in the recent EU policy debate on re-allocation of spectrum, one of the most strategically significant communication resources. The article explains the presence of the voice of civil society through construction of a model of international civil society strategic alignment and application of it to the spectrum case. The case provides evidence of how, in an environment generally dominated by state and commercial interests, civil society actors have been able to articulate influentially – though ultimately in a limited way - their public policy preferences

The potential implication of eosinophil activation in the pathogenesis of childhood asthma

Background: Asthma is now recognized as an eosinophil mediated inflammation of the airways. Pulmonary function tests are less easily performed in young children. So, measuring markers of eosinophil activation is of special importance in pediatric practice. Objective: This study aimed at evaluating the role of eosinophil protein X (EPX) as a marker for assessment of asthma attack severity and control of the exacerbation. Methods: Serum EPX was measured in 35 asthmatic Egyptian children aged between 7 and 10 and 35 age and sex matched healthy children using radioimmunoassay technique (RIA). Asthmatic patients were graded according to severity of the attack into mild, moderate and severe and the measurement was performed during and after the resolution of acute asthma attack. In addition, complete hemogram, total serum IgE, arterial blood gases and stool analysis were performed and peak expiratory flow rate (PEFR) was assessed in asthmatic children during and after acute exacerbation. Results: Serum concentrations of EPX, total serum IgE and absolute eosinophilic count (AEC) were significantly higher in asthmatic children than healthy controls (P < 0.001). Serum EPX and AEC were significantly higher in all studied groups before treatment compared to the corresponding levels of the same patients after treatment (P < 0.001). Total serum IgE was significantly higher only in mild and moderate asthma before treatment (P < 0.001). Serum EPX level was significantly elevated among patients with severe attacks (84.70 ± 7.18 μg/L) than those with moderate attacks (67.2 ± 5.31 μg/L) and patients with mild attacks (53.47 ± 11.47 μg/L)(P < 0.001). It was negatively correlated to PEFR measurement during attacks (r=-0.75, P < 0.05). A significant reduction in serum EPX and AEC was observed after the resolution and improvement of pulmonary function. Meanwhile, total serum IgE decreased after treatment with the resolution of asthma attack, yet it remained significantly higher than that of controls (P < 0.001). Conclusion: Our findings support the concept that EPX may be implicated in the pathogenesis of asthma and highlights its importance in monitoring the severity and control of asthma exacerbation. Hence, it might represent an objective guide of treatment efficacy. Keywords: EPX, Childhood asthma, pathogenesis, eosinophil activationEgypt J Pediatr Allergy Immunol 2004; 2(1): 52-5

The politics of DTT policy-making in Bulgaria: the significance of path dependencies and institutional characteristics

This thesis examines the politics of the policy process concerning the introduction of digital terrestrial television (DTT) in Bulgaria. Bulgaria is an Eastern European post-communist country and a member of the European Union (EU) since 2007. The policy of digitalisation of terrestrial broadcasting is studied from a domestic perspective that focuses on the relevance of the national institutional structures and their response to internal and external (notably EU) influences. The thesis relies primarily on the ‘new institutionalist’ theoretical approach to examine how historical path dependencies and state capacities have enabled or disabled certain types of behaviour by public and private actors which have in turn shaped the policy process. In this respect, the role of the EU is seen as refracted through the prism of domestic arrangements, capacities and interests. The thesis demonstrates that the weak institutional capacities of the Bulgarian state, political patronage, clientelism and cronyism, failed to ensure a clear, fair and transparent DTT switchover policy. Sectoral broadcasting characteristics including the prominence of pay-for platforms and small market size contributed to this result, yet the thesis argues that the extent of their impact has been determined by structural characteristics within which the desion-making process has taken place. The thesis shows that far from genuine public interest objectives - such as increased media plurality, a stronger role for PSB, more competition within and between platforms, and efficient use of spectrum - the DTT transition in the country has served to reinforce path-dependencies and historical continuities. This last point has been observed in relation to digital television policies in Western countries, such as Britain and the USA (Galperin, 2004a) and Sweden and Spain (Suarez Cantel, 2011: 318). More research is needed to confirm or not this conclusion in relation to other (post-communist) countries and other sectors

Interplay between Zeeman interaction and spin-orbit coupling in a two-dimensional semiconductor system

We analyse the interplay between Dresselhaus, Bychkov-Rashba, and Zeeman interactions in a two-dimensional semiconductor quantum system under the action of a magnetic field. When a vertical magnetic field is considered, we predict that the interplay results in an effective cyclotron frequency that depends on a spin-dependent contribution. For in-plane magnetic fields, we found that the interplay induces an anisotropic effective gyromagnetic factor that depends on the orientation of the applied field as well as on the orientation of the electron momentum.Comment: 5 page

Casual blood pressure among Tanzanian undergraduate students: need for re-defining population specific operational threshold between normotension and hypertension

Background: Despite of the recommendations to use population specific blood pressure (BP) references which consider time, ethnicity and environmental factors, there is limited information regarding BP profile among Tanzanians. This cross sectional study was done to determine casual BP profile among healthy volunteer students of the Catholic University of Health and Allied Sciences in Mwanza, Tanzania.Methods: Socio-demographic and lifestyle data were collected using questionnaires. Systolic BP (SBP) and diastolic BP (DBP) were measured using aneroid sphygmomanometer.Results: A total of 299 students (males=204; females=95) were involved in the study. Their mean age was 23.4 ± 0.2 years. SBP ranged from 82-150mmHg (mean= 115.7 ± 0.7mmHg) and DBP ranged from 44–100mmHg (mean= 71.9±0.6mmHg). Mean arterial pressure (MAP) was 86.5±0.5mmHg. Males had significantly higher BP than females; and BP was noticed to increase with increased age and body weight. Upper limits of the normal SBP and DBP calculated as mean + 2SDs and 95th percentiles were 140.5mmHg and 138mmHg, respectively and for DBP were 91.8 mmHg and 90 mmHg, respectively.Conclusion: The observed upper limits of the distribution of normal BP for the age of the participants are higher than the World Health Organization recommended values. We recommend a larger study to determine BP among healthy Tanzanians to establish the normal values

IR sensors array for robots localization using K means clustering algorithm

The position of multi-robot system in an indoor localization system is successfully estimated using a new algorithm. The localization problem is resolved by using an array of IR receiver sensors distributed uniformly in the environment. The necessary information about the localization development is collected by scanning the IR sensor array in the environment. The scheme of scanning process is done column by column to recognize and mention the position of IR receiver’s sensors, which received signals from the IR transmitter that is fixed on the robot. This principle of scanning helps to minimize the required time for robot localization. The k-means clustering algorithm is used to estimate the multi-robot locations by isolating the labeled IR receivers into clusters. Basically the multi-robot position is estimated to be the middle of each cluster. Simulation results demonstrate the advances algorithm in estimation the multi-robot positions for various dimensional IR receiver’s array