Private Index Coding

This paper has been presented at: 2018 IEEE International Symposium On Information Theory (ISIT)We study the problem of index coding under the privacy requirement that receivers do not learn anything more than the messages they already have as side information and the message they want from the server. To achieve this private index coding, we consider the use of secret keys that are shared among various subsets of users and the server. We characterize key access structures that allow private index coding. For up to three receivers, we characterize the rate region of transmission and key rates and show that scalar coding is optimal; we also show that scalar linear codes are sub-optimal for four receivers. Furthermore, when no keys are available, we consider a weaker notion of privacy analogous to weak security. Finally, for a different setting in which the server is allowed to send messages exclusively to a subset of users, we study the number of transmissions required to achieve error-free decoding and privacy.Prabhakaran and N. Karamchandani acknowledge initial discussions with Parathasarathi Panda and Vaishakh Ravi. V. Narayanan was supported by a travel fellowship from the Sarojini Damodaran Foundation. This work was done while Jithin Ravi was at Tata Institute of Fundamental Research and IIT Bombay. He has received funding from ERC grant 714161

Design of multiligand inhibitors for the swine flu H1N1 neuraminidase binding site

Viral neuraminidase inhibitors such as oseltamivir and zanamivir prevent early virus multiplication by blocking sialic acid cleavage on host cells. These drugs are effective for the treatment of a variety of influenza subtypes, including swine flu (H1N1). The binding site for these drugs is well established and they were designed based on computational docking studies. We show here that some common natural products have moderate inhibitory activity for H1N1 neuraminidase under docking studies. Significantly, docking studies using AutoDock for biligand and triligand forms of these compounds (camphor, menthol, and methyl salicylate linked via methylene bridges) indicate that they may bind in combination with high affinity to the H1N1 neuraminidase active site. These results also indicate that chemically linked biligands and triligands of these natural products could provide a new class of drug leads for the prevention and treatment of influenza. This study also highlights the need for a multiligand docking algorithm to understand better the mode of action of natural products, wherein multiple active ingredients are present

Use of Doppler Sodar in atmospheric measurements

O uso do Sodar Doppler tem trazido avanços significativos ao entendimento dos processos de camada limite atmosférica. Estes instrumentos têm demonstrado suas habilidades em um grande número de estudos, tais como circulações de brisa marítima/terrestre, escoamento em terrenos complexos, ondas de gravidade, jatos de baixos níveis e sistemas frontais, além de possibilitar estimativas quantitativas de parâmetros de turbulência tais como fluxo de calor sensível, balanço de energia cinética turbulenta, função estrutura de temperatura e a determinação da altura da camada de mistura.Neste trabalho, o princípio de funcionamento de diferentes tipos de Sodar, suas habilidades e limitações na instalação desses instrumentos são apresentados. No final, alguns fenômenos detectados por um Sodar Doppler do tipo “phased-array”, recentemente adquirido pelo IAG-USP, são apresentados

Limits on intrinsic magnetism in graphene

We have studied magnetization of graphene nanocrystals obtained by sonic exfoliation of graphite. No ferromagnetism is detected at any temperature down to 2 K. Neither do we find strong paramagnetism expected due to the massive amount of edge defects. Rather, graphene is strongly diamagnetic, similar to graphite. Our nanocrystals exhibit only a weak paramagnetic contribution noticeable below 50K. The measurements yield a single species of defects responsible for the paramagnetism, with approximately one magnetic moment per typical graphene crystallite.Comment: 2nd version, modified in response to comment

Variability of boundary layer processes for the metropolitan area of São Paulo during winter

As variações espaciais e temporais da Camada Limite planetária (CLP) da Área Metropolitana da cidade de São Paulo (RMSP) durante o período de 23 de julho a 15 de Agosto de 1999 são estudas utilizando dados de um Sodar Doppler. RMSP (λ = 23º34’ S e φ = 46º44’ W) está numa altitude de 800 m acima do nível médio do mar, localizada 60 km à noroeste do oceano Atlântico, limitada por cadeias de montanhas ao norte, tendo uma orografia complexa e configura-se numa ilha de calor urbana.Este trabalho tem o objetivo de entender o impacto da urbanização sobre os processos de CLP particularmente durante a estação de inverno. Um número de diferentes tipos de experimentos estiveram em operação durante uma campanha de inverno organizada pelo IAG-USP. O Sodar Doppler fornece dados sobre (i) função estrutura de temperatura, CT2, (ii) velocidade do vento horizontal, u, (iii) velocidade do vento vertical, w, (iv) desvios padrão do vento horizontal e vertical, σu, σv e σw, e (v) altura da inversão de temperatura, Zi.A análise dos dados fornecidos pelo Sodar mostra claramente as variações desses parâmetros em alturas indo de 50 m até 1500 m com intervalos de 50 m num intervalo de tempo de 15 minutos. Existe grande variação desses parâmetros com a altura.O aumento noturno no campo do vento horizontal com a altura é bem marcado indicando a quase ausência de transporte vertical de momento horizontal durante a noite em condições estáveis. Durante as horas da manhã a aceleração na velocidade do vento é evidente. O aumento anormal em Zi durante a noite sob condições estáveis prevalece durante o inverno com valores mais altos em agosto do que em julho

Competing risks analysis for neutrophil to lymphocyte ratio as a predictor of diabetic retinopathy incidence in the Scottish population

Background: Diabetic retinopathy (DR) is a major sight-threatening microvascular complication in individuals with diabetes. Systemic inflammation combined with oxidative stress is thought to capture most of the complexities involved in the pathology of diabetic retinopathy. A high level of neutrophil–lymphocyte ratio (NLR) is an indicator of abnormal immune system activity. Current estimates of the association of NLR with diabetes and its complications are almost entirely derived from cross-sectional studies, suggesting that the nature of the reported association may be more diagnostic than prognostic. Therefore, in the present study, we examined the utility of NLR as a biomarker to predict the incidence of DR in the Scottish population.Methods: The incidence of DR was defined as the time to the first diagnosis of R1 or above grade in the Scottish retinopathy grading scheme from type 2 diabetes diagnosis. The effect of NLR and its interactions were explored using a competing risks survival model adjusting for other risk factors and accounting for deaths. The Fine and Gray subdistribution hazard model (FGR) was used to predict the effect of NLR on the incidence of DR.Results: We analysed data from 23,531 individuals with complete covariate information. At 10 years, 8416 (35.8%) had developed DR and 2989 (12.7%) were lost to competing events (death) without developing DR and 12,126 individuals did not have DR. The median (interquartile range) level of NLR was 2.04 (1.5 to 2.7). The optimal NLR cut-off value to predict retinopathy incidence was 3.04. After accounting for competing risks at 10 years, the cumulative incidence of DR and deaths without DR were 50.7% and 21.9%, respectively. NLR was associated with incident DR in both Cause-specific hazard (CSH = 1.63; 95% CI: 1.28–2.07) and FGR models the subdistribution hazard (sHR = 2.24; 95% CI: 1.70–2.94). Both age and HbA 1c were found to modulate the association between NLR and the risk of DR.Conclusions: The current study suggests that NLR has a promising potential to predict DR incidence in the Scottish population, especially in individuals less than 65 years and in those with well-controlled glycaemic status.</p

LHC Magnet Tests: Operational Techniques and Empowerment for Successful Completion

The LHC magnet tests operation team developed various innovative techniques, particularly since early 2004, to complete the superconductor magnet tests by Feb. 2007. Overall and cryogenic priority handling, rapid on-bench thermal cycling, rule-based goodness evaluation on round-the-clock basis, multiple, mashed web systems are some of these techniques applied with rigour for successful tests completion in time. This paper highlights these operation empowerment tools which had a pivotal role for success. A priority handling method was put in place to enable maximum throughput from twelve test benches, having many different constraints. For the cryogenics infrastructure, it implied judicious allocation of limited resources to the benches. Rapid On-Bench Thermal Cycle was a key strategy to accelerate magnets tests throughput, saving time and simplifying logistics. First level magnet appraisal was developed for 24 hr decision making so as to prepare a magnet further for LHC or keep it on standby. Web based systems (Tests Management and E-Traveller) were other essential ideas to track & coordinate various stages of tests handled by different teams