Temperature wave‐trains of periodically forced networks of catalytic reactors

Networks of N identical catalytic reactors with periodically switched inlet and outlet sections are studied for first‐order irreversible exothermic reactions. Switching strategies with inlet and outlet sections periodically jumping a fixed number n_s of reactors are considered and the mechanisms governing the formation of traveling temperature wave‐trains are analyzed as n_s and N are varied. To this aim, a geometric approach to the analysis of the network energy balance is developed. Based on this approach, infinite domains of traveling temperature wave‐trains are predicted for any n_s and N. Analytical approximations are derived for the stability limits and the spatiotemporal patterns of these regimes. Stability boundaries predicted analytically include for any solution the largest part of the stability region computed by numerical simulation. Moreover, good agreement is found between the structure of the spatiotemporal patterns computed numerically and that predicted based on the proposed approach. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

Enforcing Luminescence at Organic Nanointerfaces: Luminescence Spatial Confinement and Amplification in Molecular‐Based Core–Shell Nanoparticles

Fully organic core–shell nanoparticles that promote luminescence spatial confinement and enhancement at the core–shell nanointerface are designed and prepared. These molecular‐based bicomponent nanostructures give rise to very efficient directional excitation energy transfer from the shell to acceptor molecules in the core located at the core–shell nanointerface. A striking luminescence enhancement is observed with respect to the corresponding single‐component nanoparticles, which is ascribed to large local electric fields generated at the nanointerface between the polarizable molecular core and shell.     

Spatial orientation on a vertical maze in free-ranging fox squirrels (Sciurus niger).

To determine how squirrels return to remembered locations in an arboreal environment, wild fox squirrels (Sciurus niger) were trained on an outdoor vertical maze. Squirrels were trained on 1 route and tested with all routes accessible. Possible mechanisms of spatial orientation were distinguished with manipulations such as rotations, shifts, and blocked routes. Squirrels consistently used an extra-maze, allothetic frame of reference to orient and appeared to organize their memory of the route hierarchically. This study demonstrates that a laboratory technique, the maze, can be successfully brought into the field to measure mechanisms of spatial orientation under natural conditions in free-ranging wild rodents. Such studies will allow researchers to determine what kind of spatial information is acquired by wild animals under natural conditions and how this information is used. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex influence on face recognition memory moderated by presentation duration and reencoding.

Objective: It has been suggested that women have a better face recognition memory than men. Here we analyzed whether this advantage depends on a better encoding or consolidation of information and if the advantage is visible during short-term memory (STM), only, or whether it also remains evident in long-term memory (LTM). Method: We tested short- and long-term face recognition memory in 36 nonclinical participants (19 women). We varied the duration of item presentation (1, 5, and 10 s), the time of testing (immediately after the study phase, 1 hr, and 24 hr later), and the possibility to reencode items (none, immediately after the study phase, after 1 hr). Results: Women showed better overall face recognition memory than men (ηp2 = .15, p     

Threshold protocols in survivor set systems

Many replication protocols employ a threshold model when expressing failures they are able to tolerate. In this model, one assumes that no more than t out of n components can fail, which is a good representation when failures are independent and identically distributed (IID). In many real systems, however, failures are not IID, and a straightforward application of threshold protocols yields suboptimal results. Here, we examine the problem of transforming threshold protocols into survivor-set protocols tolerating dependent failures. Our main goal is to show the equivalence between the threshold model and the core/survivor set model. Toward this goal, we develop techniques to transform threshold protocols into survivor set ones. Our techniques do not require authentication, self-verification or encryption. Our results show in one case that we can transform a threshold protocol to a subset by spreading a number of processes across processors. This technique treats a given threshold algorithm as a black box, and consequently can transform any threshold algorithm. However, it has the disadvantage that the transformation is not possible for all sets of survivor sets. The second technique instead focuses on transforming voters: functions that evaluate to a value out of a set of tallied values in a replication protocol. Voters are an essential part of many fault-tolerant protocols, and we show a universal way of transforming them. With such a transformation we expect that a large number of protocols in the literature can be directly transformed with our technique. It is still an open problem, however, if the two models are equivalent, and our results constitute an important first step in this direction.     

Reduction of Pathogens Using Hot Water and Lactic Acid on Beef Trimmings

Beef trimmings from young or mature beef cattle were obtained commercially. Trimmings within age type then were inoculated with about 6.0 log₁₀ CFU/mL of rifampicin-resistant. Escherichia coli O157:H7 and Salmonella typhimurium (ATCC 13311) were randomly assigned to 1 of 3 treatments (control; 95 °C hot water alone, or with 2% L-lactic acid). After treatment, trimmings were ground, held for 0, 14, 28, or 42 d in chub packages at 4 °C, and total aerobic plat counts, E. coli O157:H7, and S. typhimurium counts were determined. Non-inoculated trimmings were also treated and samples were evaluated for pH, fat, moisture, TBA, meat color by colorimeter, and meat color, and odor by trained sensory panels. Trimmings treated with water or hot water plus lactic acid reduced levels of E. coli O157:H7 and S. typhimurium and tended to be darker after treatment. Meat odor in the final product was not affected by treatment.     

Legumes seeds protein isolates in the production of ascorbic acid microparticles

This study evaluated the use of pea (Pisum sativum) and cowpea (Vigna unguiculata) protein isolates (PPI and CPI) in the microencapsulation of ascorbic acid (AA), by spray drying. PPI and CPI were used pure or mixed with maltodextrin (M) as wall materials of AA. The process yield was improved from 66% to 86% by the addition of M (CPI/M and PPI/M); also, AA particles yield was 79%. The AA retention from the drying process was higher in PPI/M (69%) than in CPI/M (66%), and this was attributed to PPI proteolysis profile, demonstrated by the SDS–PAGE electrophoresis. Scanning electron microscopy revealed that AA particles were similarly spherical and shriveled. Mean particle sizes of PPI/M/AA and CPI/M/AA were 7 and 8 μm, respectively. This study showed the exploration of protein isolates from legumes in the development of a microparticulate system containing AA with great potential for use in human health.     

Investigating the contribution of linguistic information to quality estimation

This paper describes a study on the contribution of linguistically-informed features to the task of quality estimation for machine translation at sentence level. A standard regression algorithm is used to build models using a combination of linguistic and non-linguistic features extracted from the input text and its machine translation. Experiments with three English–Spanish translation datasets show that linguistic features on their own are not able to outperform shallower features based on statistics from the input text, its translation and additional corpora. However, further analysis suggests that linguistic information can be useful to produce better results if carefully combined with other features. An in-depth analysis of the results highlights a number of issues related to the use of linguistic features.