Multi-path Summation for Decoding 2D Topological Codes

Fault tolerance is a prerequisite for scalable quantum computing. Architectures based on 2D topological codes are effective for near-term implementations of fault tolerance. To obtain high performance with these architectures, we require a decoder which can adapt to the wide variety of error models present in experiments. The typical approach to the problem of decoding the surface code is to reduce it to minimum-weight perfect matching in a way that provides a suboptimal threshold error rate, and is specialized to correct a specific error model. Recently, optimal threshold error rates for a variety of error models have been obtained by methods which do not use minimum-weight perfect matching, showing that such thresholds can be achieved in polynomial time. It is an open question whether these results can also be achieved by minimum-weight perfect matching. In this work, we use belief propagation and a novel algorithm for producing edge weights to increase the utility of minimum-weight perfect matching for decoding surface codes. This allows us to correct depolarizing errors using the rotated surface code, obtaining a threshold of $17.76 \pm 0.02 \%$. This is larger than the threshold achieved by previous matching-based decoders ($14.88 \pm 0.02 \%$), though still below the known upper bound of $\sim 18.9 \%$.Comment: 19 pages, 13 figures, published in Quantum, available at https://quantum-journal.org/papers/q-2018-10-19-102

Mapping the Spatial Deprivation of Pakistan

Geographical targeting may be a viable way to allocate resources for poverty alleviation in developing countries. Efficiency can be increased, and leakages to the nonpoor reduced substantially, by targeting needy areas. A national and regional database of substantial poverty maps or deprivation indices are not readily available in Pakistan. Further, existing activities of poverty alleviation are carried out on ad hoc basis in the absence of identified pockets of poverty. This paper presents indices of multiple deprivations based on the 1998 Population and Housing Census data. Possible applications of this exercise include identifying areas of need, making decisions on regional and sectoral priorities, facilitating targeted public interventions through special poverty alleviation programmes, understanding the relationship between poverty and its causes, and helping federal and provincial governments in determining financial awards.

Interactions of Plasmonic Nanoparticles with Photosynthetic Complexes

Tailored metallic nanoparticles (NPs) coupled to specific proteins (bio-nanohybrids) can provide tunable functional materials at the nanoscale. Malleable characteristics of the NPs and diversity of the protein functions widen the horizons of conceivable applications of such bio-nanohybrids. In the presented work the interplay between Photosystem I (PSI) from Thermosynechococcus elongatus (T. elongatus) and different plasmonic NPs was investigated. PSI, an abundant photoactive pigment-protein complex is the essential component of photosynthesis. It binds 300 chlorophyll molecules (Chl a) per trimer within its protein scaffolding to facilitate the conversion of solar energy into chemical energy. PSI complexes were coupled to different mono- and bimetallic NPs and corresponding plasmonic interaction effects on the fluorescence properties of the PSI were investigated using single-molecule spectroscopy (SMS). The used metallic NPs were fabricated by thermal annealing of thin metallic films. Measurements were performed at different temperatures in a range 1.6 - 250 K and variations in the emission properties of isolated and NP-coupled PSI complexes were analyzed comprehensively. Interactions with bimetallic NPs exhibiting various metallic compositions were studied at cryogenic temperature (1.6 K). The fluorescence emission of the PSI was intensified upon coupling with NPs. Different compositions of the bimetallic NPs resulted in different enhancement factors (EFs). NPs with Au/Au composition led the maximum enhancement followed by the Ag/Au and Au/Ag. On average the fluorescence was enhanced up to 4.4 (Au/Au), 2.3 (Ag/Au), and 1.1 (Au/Ag)-fold. For individual complexes, however, EFs even up to 22.9 (Au/Au), 5.1 (Ag/Au), and 1.7 (Au/Ag)-fold were observed.The enhancement of the fluorescence demonstrated strong wavelength dependence for all compositions. This was explained considering the largely extended multichromophoric composition of PSI. To further study the impact of temperature on metal-enhanced fluorescence (MEF) of PSI, monometallic NPs composed of gold only were employed. Measurements were performed at 1.6, 90, 190 and 250 K. A strong temperature dependence of the shape and intensity of the emission spectra was noticed. On average the fluorescence was enhanced 4.3 (1.6 K), 19.4 (90 K), 57.6 (190 K) and 84.0 (250 K)-fold. However, for individual complexes, the EFs up to 230, 250 and even 441-fold were observed. The remarkable increase in EFs at higher temperatures was discussed taking into account the low initial fluorescence yield of PSI, an increase in excitation rate, appearance of new emission channels due to altered excitation energy transfer (EET) pathways and increased spectral overlap between absorption spectrum of gold nanoparticles (AuNPs) and emission spectrum of PSI. In the last part, photopatterned self-assembled monolayers (SAMs) of the thiols were applied to achieve a precise and controlled attachment of the proteins to the gold substrate. Two thiols, i.e., perfluorinated and carboxylic acid-terminated were applied to prevent the unwanted and encourage the wanted adsorption, respectively. Different surface analysis techniques were used to examine the formation and photopatterning of the SAMs. It was noticed that to ensure the complete photooxidation of the perfluorinated thiol, it is essential to use a specific wavelength of UV light. Perfluorinated thiol did not prove a strong resister against unwanted attachment, as an adequate amount of the PSI was found at nonspecific sites. Carboxylic acidterminated thiol, however, fulfilled the objective and appeared as a suitable candidate to encourage the desired attachment of the PSI

Evaluation of the cytotoxic and antiviral effects of ethanol extract of three Opuntia species of Peste des Petits ruminant virus

Purpose: To assess in vitro the virocidal effects of different species of cactus plant on the lethal action of Peste des petits virus (PPRV).Method: Ethanol extracts of different cactus plants were obtained. A serial twofold dilution of the extracts was prepared. Cytotoxic and antiviral activities were examined through MTT assay at various concentrations. Vero cell lines were grown in 96 well plates up to an 80 % confluent monolayer. The plates were divided into two groups, one for antiviral and the other for cytotoxicity activity. The cells were exposed to various concentrations of the ethanol extracts to assess the cytotoxicity, whereas to assess the antiviral activity, PPRV was re-incubated with the extracts and then exposed to cells. MMT dye was added and the results were evaluated as cell survival (%).Results: At higher concentrations, i.e., 500 - 1000 μg/mL, ethanol extracts from all the Opuntia species displayed cytotoxic effects. The ethanol extract of OM exhibited the greatest antiviral potential of all the extracts, while the extract of Opuntia stricta (OS) was the least effective against PPRV in the cultured cells. There were significant differences (p < 0.05) in the concentration of Opuntia manocantha (OM), Opuntia delinii OD and Opuntia stricta (OS) with reference to antiviral activity. OM showed antiviral activity against PPRV from 3.25 to 125 μg/mL, OD antiviral activity from 31.25 to 62.5 ug/ml whereas OS showed antiviral activity at 2.5 μg/mLConclusion: The ethanol extract of Opuntia species reduces the infection of PPRV in Caprine. Keywords: Cactus, Opuntia spp., Peste des petits ruminants virus (PPRV), Vero cell lin

The democratic stature of Pakistan in the contemporary world: challenges and prospects

Pakistan holds a very important geopolitical position not only within South Asia but also in relation to the rest of the world. Connecting East and West, and with the potentiality for bridging the Global South with the North, it forms an important locus for discussing the role of democracy and democratic institutions in bringing about and sustaining peace. With attention on the 2013 election season, this article explores strategies for stakeholders within Pakistan, the aim being the improvement of prospects for democracy and prosperit

Interference Analysis for Vehicle-to-Vehicle Communications at 28 GHz

High capacity and ultra-reliable vehicular communication are going to be important aspects of beyond 5G communication networks. However, the vehicular communication problem becomes complex at a large scale when vehicles are roaming on the road, while simultaneously communicating with each other. Moreover, at higher frequencies (like 28 GHz), the dynamics of vehicular communication completely shift towards unpredictability and low-reliability. These factors may result in high packet error and a large amount of interference, resulting in regular disruptions in communications. A thorough understanding of performance variations is the key to moving towards the next generation of vehicular networks. With this intent, this article aims to provide a comprehensive interference analysis, wherein the closed-form expressions of packet error probability (PEP) and ergodic capacity are derived. Using the expression of the PEP, diversity analysis is provided which unveils the impact of channel nonlinearities on the performance of interference-constrained vehicular networks. The insights provided here are expected to pave the way for reliable and high capacity vehicular communication networks

Consumer Behavior in Fast Food Marketing in Bangladesh: A Case Study

The main objective of the study is to identify the determinants that influence consumer satisfaction in fast food marketing in Bangladesh. Data were collected from the students in a private industry in Dhaka city. Principal component factor analysis and SEM are employed for analyzing data. The results indicate that among the six explanatory variables, five are observed to statistically significantly influence consumer satisfaction in the fast food industry. These variables are food quality, service quality, food variety, outlet environment and convenient location. Keywords: Fast food, Consumer behavior, Consumer satisfaction, Factors, Marketin

Pharmacological and therapeutic potential of Oxalis corniculata

Oxalis corniculata is commonly known as Indian wood Sorrel. In Unani it is called as Hummaz and distributed in the whole northern temperate zone, United State of America, Arizona and throughout India. Oxalis corniculata is used in Unani medicine in the management of liver disorders, jaundice, skin diseases, urinary diseases etc. The plant been proven to possess various pharmacological activities like liver tonic, appetizer, diuretic, anthelmintic, emmenagogue, anti-inflammatory, analgesic, anti-pyretic, blood purifier etc. Here we summarize the therapeutic potential of Oxalis corniculat

A novel collaborative IoD-assisted VANET approach for coverage area maximization

Internet of Drones (IoD) is an efficient technique that can be integrated with vehicular ad-hoc networks (VANETs) to provide terrestrial communications by acting as an aerial relay when terrestrial infrastructure is unreliable or unavailable. To fully exploit the drones' flexibility and superiority, we propose a novel dynamic IoD collaborative communication approach for urban VANETs. Unlike most of the existing approaches, the IoD nodes are dynamically deployed based on current locations of ground vehicles to effectively mitigate inevitable isolated cars in conventional VANETs. For efficiently coordinating IoD, we model IoD to optimize coverage based on the location of vehicles. The goal is to obtain an efficient IoD deployment to maximize the number of covered vehicles, i.e., minimize the number of isolated vehicles in the target area. More importantly, the proposed approach provides sufficient interconnections between IoD nodes. To do so, an improved version of succinct population-based meta-heuristic, namely Improved Particle Swarm Optimization (IPSO) inspired by food searching behavior of birds or fishes flock, is implemented for IoD assisted VANET (IoDAV). Moreover, the coverage, received signal quality, and IoD connectivity are achieved by IPSO's objective function for optimal IoD deployment at the same time. We carry out an extensive experiment based on the received signal at floating vehicles to examine the proposed IoDAV performance. We compare the results with the baseline VANET with no IoD (NIoD) and Fixed IoD assisted (FIoD). The comparisons are based on the coverage percentage of the ground vehicles and the quality of the received signal. The simulation results demonstrate that the proposed IoDAV approach allows finding the optimal IoD positions throughout the time based on the vehicle's movements and achieves better coverage and better quality of the received signal by finding the most appropriate IoD position compared with NIoD and FIoD schemes. © 2013 IEEE