Learning Boolean Halfspaces with Small Weights from Membership Queries

We consider the problem of proper learning a Boolean Halfspace with integer weights $\{0,1,\ldots,t\}$ from membership queries only. The best known algorithm for this problem is an adaptive algorithm that asks $n^{O(t^5)}$ membership queries where the best lower bound for the number of membership queries is $n^t$ [Learning Threshold Functions with Small Weights Using Membership Queries. COLT 1999] In this paper we close this gap and give an adaptive proper learning algorithm with two rounds that asks $n^{O(t)}$ membership queries. We also give a non-adaptive proper learning algorithm that asks $n^{O(t^3)}$ membership queries

Pathogenic Activation of Mesenchymal Stem Cells is induced by the Disease Microenvironment in Systemic Sclerosis

Objective: In systemic sclerosis (SS c), a persistent tissue repair process leads to progressive fibrosis of the skin and internal organs. The role of mesenchymal stem cells (MSC s), which characteristically initiate and regulate tissue repair, has not been fully evaluated. We undertook this study to investigate whether dividing metakaryotic MSC s are present in SS c skin and to examine whether exposure to the disease microenvironment activates MSC s and leads to transdifferentiation. Methods: Skin biopsy material from patients with recent‐onset diffuse SS c was examined by collagenase spread of 1‐mm–thick surface‐parallel sections, in order to identify dividing metakaryotic stem cells in each tissue plane. Adipose‐derived MSC s from healthy controls were treated with dermal blister fluid (BF ) from patients with diffuse SS c and profiled by next‐generation sequencing, or they were evaluated for phenotypic changes relevant to SS c. Differential responses of dermal fibroblasts were studied in parallel. Results: MSC ‐like cells undergoing active metakaryotic division were identified in SS c sections (but not control sections) most prominently in the deep dermis and adjacent to damaged microvessels, in both clinically involved and uninvolved skin. Furthermore, exposure to SS c BF caused selective MSC activation, inducing a myofibroblast signature, while reducing signatures of vascular repair and adipogenesis and enhancing migration and contractility. Microenvironmental factors implicated in inducing transdifferentiation included the profibrotic transforming growth factor β, the presence of lactate, and mechanosensing, while the microenvironment Th2 cytokine, interleukin‐31, enhanced osteogenic commitment (calcinosis). Conclusion: Dividing MSC ‐like cells are present in the SS c disease microenvironment where multiple factors, likely acting in concert, promote transdifferentiation and lead to a complex and resistant disease state

Factors influencing the geographic distribution of physicians in Iran: A qualitative study

Introduction: The uneven geographic distribution of physicians has been a longstanding important issue worldwide. Different policies have been recently employed in Iran, with the aim of bridging the gap. This study aimed to explore factors influencing the distribution of specialist physicians in Iran and investigate the effects of newly established policies on attracting and retaining physicians in rural and remote areas. Methods: This qualitative study was conducted in 2012. Qualitative data were obtained through an open-ended questionnaire and by reviewing relevant documents. Participants were 82 key officials from medical universities, who were directly involved in the distribution of physicians across the country, including vice chancellors for treatment affairs, managers for treatment affairs, and human resources experts. Thematic analysis was used to analyse qualitative data. Results: Four main factors influencing the distribution of physicians were explored, namely external, contextual, individual, and organizational factors. The decision to practice in rural areas was mainly influenced by socioeconomic characteristics of the designated areas and personal attributes of physicians, including sex, income expectations, and rural background. Participants also asserted that the implemented policies had a major positive influence on the distribution of physicians. In addition, participants believed that the improvement in the distribution of physicians had both positive economic and health impacts in underdeveloped areas. Conclusions: It seems that the regional distribution and supply of physicians have been improved in the light of the implemented policies in recent years. The study also revealed that a number of factors influence physician choices to stay and practice in rural and underdeveloped areas. Policies such as providing more financial and non-financial incentives, reducing disparities between physicians' income in rural and metropolitan areas, selection of students with rural background, and supportive measures for physicians working in underserved areas were recommended. © H Ravaghi, E Taati, Z Abdi, A Meshkini, S Sarvarizadeh, 2015

PENGUJIAN KEMAMPUAN ADSORPSI DARI ADSORBEN ALUMINA AKTIF UNTUK MESIN PENDINGIN TENAGA SURYA

Akhir-akhir ini mesin pendingin siklus adsorpsi semakin banyak diteliti oleh para ahli karenadisamping ekonomis juga ramah lingkungan dan menggunakan energy terbarukan yaitu energi surya.Agar proses adsorpsi dan desorpsi mesin pendingin adsorpsi dapat berjalan dengan baik perludiketahui jumlah perbandingan yang ideal antara adsorben dengan refrigeran yang digunakan. Disiniuntuk mencari perbandingan antara absorben alumina aktif menggunakan baut maupun tidakmenggunakan baut. Data tersebut dapat dicari menggunakan alat penguji kapasitas adsorpsi. Alatpenguji kapasitas adsorpsi yang digunakan dilengkapi dengan lampu halogen 1000 W sebagai sumberpanas. Adsorber pada alat penguji ini terbuat dari bahan stainless steel yang bertujuan agar tahanterhadap korosi akibat dari variasi refrigeran yang digunakan. Alumina aktif yang digunakan sebagaiadsorben sebanyak 1 kg. Sedangkan variasi refrigeran yang digunakan yaitu amonia. Kapasitas amoniayang dapat diadsorpsi dan didesorpsi oleh adsorben alumina aktif mengunakan baut diisolasi adalahsebanyak 300 mL. Sedangkan kapasitas amonia yang dapat diadsorpsi dan didesorpsi oleh adsorbenalumina aktif tidak menggunakan baut diisolasi adalah sebanyak 220 mL

Seroepidemiological Study of Human Hydatidosis in Meshkinshahr District, Ardabil Province, Iran

Background: The aim of this study was to conduct a sero-epidemiological survey in Meshkinshahr, Arda­bil Province, northwestern Iran to detect the rate of hydatidosis in the city and nearby villages. Literature shows that no such study has been conducted so far.Methods: Overall, 670 serum samples were collected from 194 males and 476 females from patients re­ferred to different health centers of the region. All patients filled out a questionnaire and an informed con­sent. Sera were analyzed using indirect-ELISA test. Ten μg /ml antigens (Antigen B derived from hydatid cyst fluid), serum dilutions of 1:500 and conjugate anti-human coombs with 1:10000 dilutions were util­ized to perform the test. Data analysis was conducted using SPSS software ver. 11.5. Results: The seroprevalence of human hydatidosis was 1.79% by ELISA test in the region. This rate for fe­males was 1.68% and males 2.6%, respectively. There was no significant difference as regards all fac­tors studied and the seropositivity. According to job, farmers and ranchmen had the highest rate of infec­tion as 3.17%. The sero-prevalence of infection was 2.6%% in illiterate people which showed the highest rate. As regards residency, urban life showed no significant difference with rural life (1.1% vs. 2.58%). Age group of 69-90 yr old, with 4.62% as prevalence had the highest rate of positivity.Conclusion: Obtained sero-prevalence of hydatidosis shows more or less a resemblance to other cities of Iran, although due to the specific condition of the city we expected more rate of sero-positivity

The Impact of the Gold Mining on the Social, Economic, Andcultural in the Bombana District Southeast Sulawesi Province

The phenomenon of a gold mine brings a lot of changes in people's daily life in the Bombana District. This study aims to: (a) Aware of the social and cultural changes in society before and after the gold mining business, and (b) Knowing the changes in people's income before and after the gold mining business. The study population is the people who are in the gold mining sites. This study result, namely: (a) Gold mining have negative impact on social, economic, and cultural of communities around the gold mining area. Social, economic, and cultural societies tend to be in better shape before the gold mining. Average income communities after the gold mining increase by Rp 755.392 per month. (c) Gold mining do not increase the welfare of society, especially for farmers. The implication of this study is the government should strictly supervise and tighten even a moratorium against IUP, and gold mining companies should have corporate social responsibility (CSR) in the form of incentives to the affected communities of the businesses under their management in the fields of education, health, agriculture, economics, and culture as well as other aspects relating to the welfare of society