One-to-Many: Context-Oriented Code for Concurrent Error Detection

The paper deals with context-oriented codes for concurrent error detection. We consider a fault model for which, in the presence of a fault, the values on the circuit’s output are arbitrary. This model allows one to design an error detection code without analyzing sensitive parts or error cones in the synthesized circuit. Conventional coding schemes are based on a one-to-one mapping between an original output vector (information word) and a codeword. In this paper, we introduce a different approach, which we call one-to-many coding. In one-to-many code, each codeword comprises a predefined set of words. The functional unit is referred to as an encoder enabling each activation to map an information word to a different word. This flexible mapping system results in a lower implementation cost of the functional unit and its checker.     

Maternal N-Acetyl-Cysteine Prevents Neonatal Hypoxia-Induced Brain Injury in a Rat Model

Perinatal hypoxia is a major cause of infant brain damage, lifelong neurological disability, and infant mortality. N-Acetyl-Cysteine (NAC) is a powerful antioxidant that acts directly as a scavenger of free radicals. We hypothesized that maternal-antenatal and offspring-postnatal NAC can protect offspring brains from hypoxic brain damage.Sixty six newborn rats were randomized into four study groups. Group 1: Control (CON) received no hypoxic intervention. Group 2: Hypoxia (HYP)-received hypoxia protocol. Group 3: Hypoxia-NAC (HYP-NAC). received hypoxia protocol and treated with NAC following each hypoxia episode. Group 4: NAC Hypoxia (NAC-HYP) treated with NAC during pregnancy, pups subject to hypoxia protocol. Each group was evaluated for: neurological function (Righting reflex), serum proinflammatory IL-6 protein levels (ELISA), brain protein levels: NF-κB p65, neuronal nitric oxide synthase (nNOS), TNF-α, and IL-6 (Western blot) and neuronal apoptosis (histology evaluation with TUNEL stain). Hypoxia significantly increased pups brain protein levels compared to controls. NAC administration to dams or offspring demonstrated lower brain NF-κB p65, nNOS, TNF-α and IL-6 protein levels compared to hypoxia alone. Hypoxia significantly increased brain apoptosis as evidenced by higher grade of brain TUNEL reaction. NAC administration to dams or offspring significantly reduce this effect. Hypoxia induced acute sensorimotor dysfunction. NAC treatment to dams significantly attenuated hypoxia-induced acute sensorimotor dysfunction. Prophylactic NAC treatment of dams during pregnancy confers long-term protection to offspring with hypoxia associated brain injury, measured by several pathways of injury and correlated markers with pathology and behavior. This implies we may consider prophylactic NAC treatment for patients at risk for hypoxia during labor.     

Adaptations for Wear Resistance and Damage Resilience: Micromechanics of Spider Cuticular “Tools”

In the absence of minerals as stiffening agents, insects and spiders often use metal‐ion cross‐linking of protein matrices in their fully organic load‐bearing “tools.” In this comparative study, the hierarchical fiber architecture, elemental distribution, and the micromechanical properties of the manganese‐ and calcium‐rich cuticle of the claws of the spider Cupiennius salei, and the Zn‐rich cuticle of the cheliceral fangs of the same animal are analyzed. By correlating experimental results to finite element analysis, functional microstructural and compositional adaptations are inferred leading to remarkable damage resilience and abrasion tolerance, respectively. The results further reveal that the incorporation of both zinc and manganese/calcium correlates well with increased biomaterial's stiffness and hardness. However, the abrasion‐resistance of the claw material cross‐linked by incorporation of Mn/Ca‐ions surpasses that of many other non‐mineralized biological counterparts and is comparable to that of the fang with more than triple Zn content. These biomaterial‐adaptation paradigms for enhanced wear‐resistance may serve as novel design principles for advanced, high‐performance, functional surfaces, and graded materials.     

Observed sibling interaction: Links with the marital and the mother–child relationship.

The study examines whether the link between the marital relationship and sibling interaction is direct or mediated by the mother–child relationship. Seventy-three same-sex sibling pairs aged 3 years 6 months to 8 years 6 months were observed during free play. Mothers completed questionnaires assessing marital functioning and their relationship with their 2 children. Results indicated that older siblings' negative behavior is linked with negative dimensions of the marital and the mother–child relationship, whereas younger siblings' negative behavior is linked with the mother–child and the differential mother–child relationship. Siblings' positive behavior, although linked with spacing, is not linked with positive dimensions of family interaction. Most important, the linkage between negative marital relations and older siblings' negative behavior was found to be mediated by maternal power assertion, thereby supporting the indirect model of negative family interaction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Does Hydride Ion Transfer from Silanes to Carbenium Ions Proceed Via a Rate-Determining Formation of a Silicenium Ion or Via a Rate-Determining Electron Transfer? An Ab Initio Quantum Mechanical Study and a Curve-Crossing Analysis

The hydride transfer reactions from simple silanes to carbenium ions are studied by ab initio calculations. The simplest reaction, H₄Si + CH₃⁺ → H₃Si⁺ + CH₄, is also studied with inclusion of the solvent effect (with the SCRF method) in the ab initio scheme. Under all conditions the preferred mechanism is the synchronous hydride transfer (SHT), which is barrierless in the gas phase but possesses small barriers in solution. The mechanistic alternative involving a rate-determining single electron transfer (SET) step followed by H-atom abstraction is found to be of very high energy. Modelling of the primary isotope effect for the SHT process of H₃SiH(D) + CH₃* → H₃Si⁺ + H₃CH(D) shows that the primary isotope effect is small, between ca. 1.1 and 2.7, for the entire relevant range of Si—H(D) distances (1.5–2.3 Å). Furthermore, the pattern of the computed primary isotope effect shows it to be an insensitive probe of the SHT mechanism. The curve-crossing method is used to model the mechanistic dichotomy. It is shown that the reaction profiles for both SHT and SET arise from an avoided crossing between the ground state and a charge transfer state of the R₃SiH//R′₃C⁺ reactant pair. Thus, in the SHT mechanism a single electron switches sites in synchronicity with bond reorganization, while in SET the electron switch precedes the bond coupling. This avoided bond coupling is the foremost disadvantage of the SET mechanism. The common origin of the avoided crossing elucidates the reason why SHT exhibits characteristics of an electron transfer process without actually being a SET process.     

On inference for threshold autoregressive models

We provide a complete Bayesian method for analyzing a threshold autoregressive (TAR) model when the order of the model is unknown. Our approach is based on a version (Godsill (2001)) of the reversible jump algorithm of Green (1995), and the method for estimating marginal likelihood from the Metropolis-Hasting algorithm by Chib and Jeliazkov (2001). We illustrate our results with simulated data and the Wolfe’s sunspot data set. This research is supported in part by NSF Grant SCREMS 0112219.     

Glucosinolate Desulfation by the Phloem-Feeding Insect <Emphasis Type="Italic">Bemisia tabaci</Emphasis>

Glucosinolates are plant secondary defense metabolites confined nearly exclusively to the order Brassicales. Upon tissue rupture, glucosinolates are hydrolyzed to various bioactive breakdown products by the endogenous plant enzyme myrosinase. As the feeding of chewing insect herbivores is associated with plant tissue damage, these insects have developed several independent strategies for coping with the glucosinolate-myrosinase defense system. On the other hand, our knowledge of how phloem-feeding insects interact with the glucosinolate-myrosinase system is much more limited. In fact, phloem feeders might avoid contact with myrosinase altogether so their susceptibility to intoxication by glucosinolate hydrolysis products is unclear. Previous studies utilizing Arabidopsis thaliana plants accumulating high levels of aliphatic- or indolic-glucosinolates indicated that both glucosinolate groups have moderate negative effects on the reproductive performance of Bemisia tabaci, a generalist phloem-feeding insect. To get a deeper understanding of the interaction between B. tabaci and glucosinolate-defended plants, adults were allowed to feed on artificial diet containing intact glucosinolates or on Brussels sprout and A. thaliana plants, and their honeydew was analyzed for the presence of possible metabolites. We found that B. tabaci is capable of cleaving off the sulfate group of intact glucosinolates, producing desulfoglucosinolates that cannot be activated by myrosinases, a mechanism described to date only in several chewing insect herbivores. The presence of desulfated glucosinolates in the honeydew of a generalist phloem-feeder may indicate the necessity to detoxify glucosinolates, likely due to some level of cellular damage during feeding, which results in glucosinolate activation, or as a mechanism to circumvent the non-enzymatic breakdown of indolic glucosinolates.     

Bringing order to BGP: Decreasing time and message complexity

The Border Gateway Protocol (BGP), the de facto routing protocol of the internet, generates excessive amount of traffic following changes in the underlying backbone. Previous papers [C. Labovitz, R. Wattenhofer, S. Venkatachary, A. Ahuja, The impact of internet policy and topology on delayed routing convergence, in: Proceedings of the INFOCOM, April 2001; C. Labovitz, A. Ahuja, A. Bose, F. Jahanianitz, Delayed internet routing convergence, in: Sigcomm, September 2000.] show that BGP suffers from high convergence delay and high message complexity after a fail down (detachment) of a network, due to path exploration caused by a limited version of the counting to infinity problem.Surprisingly, we show in this paper that BGP suffers from a high message complexity also after an up event (reattachment of a network). We analyze BGP dynamics data from raw update dumps and show that race conditions cause extensive path exploration that increases the amount of redundant updates. We show, based on these BGP dynamics, that up to 26% of the updates sent during up events are redundant. We also find that the effect of this phenomenon is bigger when the change occurs at the edge of the network.We suggest a minor modification to the waiting rule of BGP that pseudo orders the network and reduces the convergence latency of up events by half and the message complexity from O(DE) to O(E), where D is the Diameter of the internet and E is the number of connections between ASes. Our simulation results suggest that our modification may improve the convergence messages and time during all events, with the most noted improvement of up to 36% in the number of messages and 81% in time to convergence during up events in Internet like topologies. We show that our results hold also for partial deployment of the modification in only some of the routers.