Relaying protocols for two colocated users

We consider a wireless network where a remote source sends information to one of two colocated users, and where the second user can serve as a relay. The source's transmission is subjected to quasi-static flat Rayleigh fading, while the transmission of the relay experiences a fixed amplitude gain with a uniform random phase, capturing its close proximity to the destination. All communications share the same time/bandwith resources, and perfect channel state information is known only to the receivers. We propose relaying protocols which are based on Wyner-Ziv quantization at the relay, and demonstrate their high efficiency (in terms of expected throughput) with respect to previously reported relaying schemes based on amplify-and-forward and decode-and-forward. A salient feature of these protocols is that the relay need not know the actual fading gain experienced by the destination in order to perform the quantization. We also consider a hybrid amplify-quantize-decode-and-forward scheme which exhibits superior performance.     

Observations of Aggressive Children During Peer Provocation and With a Best Friend.

Observational methods were used to examine aggressive children's peer relations in 2 contexts: when being teased by a peer and when interacting with a best friend. Because aggressive children may have more difficulty than nonaggressive children in both peer contexts, the authors also examined whether relations between behaviors across contexts varied as a function of aggression. Results indicated that aggression was related to children's behavior when provoked. Children's behavior when provoked was associated with fewer positive and more negative interactions with their best friend, particularly for aggressive children. Results are discussed with respect to social norms in middle childhood and informing interventions for aggressive children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Magnetic flux array for spontaneous magnetic reconnection experiments

Experimental investigation of reconnection in magnetized plasmas relies on accurate characterization of the evolving magnetic fields. In experimental configurations where the plasma dynamics are reproducible, magnetic data can be collected in multiple discharges and combined to provide spatially resolved profiles of the plasma dynamics. However, in experiments on spontaneous magnetic reconnection recently undertaken at the Versatile Toroidal Facility at MIT, the reconnection process is not reproducible and all information on the plasma must be collected in a single discharge. This paper describes a newly developed magnetic flux array which directly measures the toroidal component of the magnetic vector potential, A(phi). From the measured A(phi), the magnetic field geometry, current density, and reconnection rate are readily obtained, facilitating studies of the three-dimensional dynamics of spontaneous magnetic reconnection. The novel design of the probe array allows for accurate characterization of profiles of A(phi) at multiple toroidal angles using a relatively small number of signal channels and with minimal disturbance of the plasma.     

Characterization of the lactic acid bacteria in ewe's milk and cheese from northwest Argentina

Indigenous lactic acid bacteria in ewe's milk and artisanal cheese were studied in four samples of fresh raw milk and four 1-month-old cheeses from the provinces of northwest Argentina. Mean growth counts on M17, MRS, and MSE agar media did not show significant differences (P < 0.05) in raw milk and cheeses. Isolates of lactic acid bacteria from milk were identified as Enterococcus (48%), lactococci (14%), leuconostocs (8%), and lactobacilli (30%). All lactococci were identified as Lactococcus lactis (subsp. lactis and subsp. cremoris). Lactobacilli were identified as Lactobacillus plantarum (92%) and Lactobacillus acidophilus (8%). Enterococci (59%) and lactobacilli (41%) were isolated from cheeses. L. plantarum (93%), L. acidophilus (5%), and Lactobacillus casei (2%) were most frequently isolated. L. lactis subsp. lactis biovar diacetylactis strains were considered as fast acid producers. L. lactis subsp. cremoris strains were slow acid producers. L. plantarum and L. casei strains identified from the cheeses showed slow acid production. The majority of the lactobacilli and Lactococcus lactis strains utilized citrate and produced diacetyl and acetoin in milk. Enzyme activities (API-ZYM tests) of lactococci were low, but activities of L. plantarum strains were considerably higher. The predominance of L. plantarum in artisanal cheese is probably important in the ripening of these cheeses due to their physiological and biochemical characteristics.     

Physical association of starch biosynthetic enzymes with starch granules of maize endosperm. Granule-associated forms of starch synthase I and starch branching enzyme II

Antibodies were used to probe the degree of association of starch biosynthetic enzymes with starch granules isolated from maize (Zea mays) endosperm. Graded washings of the starch granule, followed by release of polypeptides by gelatinization in 2% sodium dodecyl sulfate, enables distinction between strongly and loosely adherent proteins. Mild aqueous washing of granules resulted in near-complete solubilization of ADP-glucose pyrophosphorylase, indicating that little, if any, ADP-glucose pyrophosphorylase is granule associated. In contrast, all of the waxy protein plus significant levels of starch synthase I and starch branching enzyme II (BEII) remained granule associated. Stringent washings using protease and detergent demonstrated that the waxy protein, more than 85% total endosperm starch synthase I protein, and more than 45% of BEII protein were strongly associated with starch granules. Rates of polypeptide accumulation within starch granules remained constant during endosperm development. Soluble and granule-derived forms of BEII yielded identical peptide maps and overlapping tryptic fragments closely aligned with deduced amino acid sequences from BEII cDNA clones. These observations provide direct evidence that BEII exits as both soluble and granule-associated entities. We conclude that each of the known starch biosynthetic enzymes in maize endosperm exhibits a differential propensity to associate with, or to become irreversibly entrapped within, the starch granule.     

Categorization of Lung Morphology Based on FRC and Height: Computer Simulations of Aerosol Deposition

The aim of this study was to compare the human subject experimental measurements of particle deposition within the lungs using the aerosol bolus technique with the results of analytical modeling as a basis for assessing the influence of lung morphology on inhaled particle deposition patterns. A methodology for scaling the lung morphology, based on a classic symmetric dichotomous model, as a function of both functional residual capacity and height of the investigated population is presented. Because of the availability of deposition data for male and female lung morphologies, these were used as an example to address the importance of adjusting lung morphology in calculating the aerosol deposition rates. In order to represent the 2 groups based on gender enrolled in the experimental study, 2 lung morphologies have been built. An analytical and mechanistic model was used to mimic the bolus delivery technique and simulate the aerosol deposition in each of the 2 groups. Predicted results were compared with experimental data for both total deposition fraction and bolus recovery (fraction of exhaled particles compared with inhaled particles) for 3 flow rates and 3 particle sizes. Good agreement was found between theoretical and measured data, showing the primary importance of the differentiation of the lung morphology to predict the aerosol deposition within human lungs. This study presents a morphological lung model that is adaptable to specific populations (e.g., gender or race), groups (e.g., a clinical study population), or even individuals.

Copyright 2012 American Association for Aerosol Research     

Which Languages Have 4-Round Zero-Knowledge Proofs?

We show that if a language L has a 4-round, black-box, computational zero-knowledge proof system with negligible soundness error, then [`(L)] ? MA\bar{L}\in \mathsf{MA}. Assuming the polynomial hierarchy does not collapse, this means in particular that NP-complete languages do not have 4-round zero-knowledge proofs with black-box simulation.     

In-Situ Analyzing the Influence of Thermoelectromagnetic Convection on the Nucleation Ahead of the Advancing Interface During Directional Solidification

Sn-3wt%Pb alloy was directionally solidified without and with a 0.08T transverse magnetic field(TMF),and real-time recorded by in-situ synchrotron X-ray imaging.Results indicate that TMF shortened the distance from the location of nucleation to the advancing interface,and accelerated the growth rate of the equiaxed crystal,which caused the columnar-to-equiaxed transition(CET)finally.The thermoelectromagnetic convection(TEMC)in front of the interface and around the crystal’s dendritic branch should respond to changes of the distance and the growth rate.