Causal dynamic inference

We suggest a general logical framework for causal dynamic reasoning. As a first step, we introduce a uniform structural formalism and assign it two kinds of semantics, abstract dynamic models and relational models. The corresponding completeness results are proved. As a second step, we extend the structural formalism to a two-sorted state-transition calculus, and prove its completeness with respect to the associated relational semantics.     

Global view on reactivity: switch graphs and their logics

The notion of reactive graph generalises the one of graph by allowing the base accessibility relation to change when its edges are traversed. Can we represent these more general structures using points and arrows? We prove this can be done by introducing higher order arrows: the switches. The possibility of expressing the dependency of the future states of the accessibility relation on individual transitions by the use of higher-order relations, that is, coding meta-relational concepts by means of relations, strongly suggests the use of modal languages to reason directly about these structures. We introduce a hybrid modal logic for this purpose and prove its completeness.     

Numerical analysis of instrumented mechanically stabilized gabion walls with large vertical reinforcement spacing

The paper describes numerical models that were developed to simulate the performance of two instrumented mechanically stabilized earth walls constructed in Izmir, Turkey. These walls were constructed with gabion facing, hybrid reinforcement layers, and fill on a rigid foundation. The hybrid reinforcement layers comprised primary reinforcement (geogrid) and secondary reinforcement (wire mesh). The vertical spacing between the primary reinforcement changed from 1 m to 2 m in two walls while other properties were kept the same. The responses of the field walls at the end of construction were simulated and compared with the numerical results. The results calculated from the numerical models showed generally good agreement with the measured wall facing displacements, horizontal fill displacements, and tensile forces in the geogrid and in the wire mesh. The maximum calculated facing displacements for the walls with 1 m and 2 m reinforcement spacing were 30.7 and 36.4 mm, respectively. The maximum tensile forces in the geogrid layers were increased by 1.5 times in the 2 m spacing wall as compared with the 1 m spacing wall due to the increase of primary reinforcement spacing. However, the spacing change did not have an obvious effect on the increase of tensile forces in the secondary reinforcement (the wire mesh). The calculated results were also compared with theoretical results relating to the earth pressure distributions and the location of the maximum tensile strains in the primary reinforcement. The horizontal earth pressures against the wall facing were close to the active earth pressures for both walls. The maximum tensile strain line of the reinforcement was close to the Rankine's failure line.     

二氧化氯通过激活苯丙烷代谢加速马铃薯块茎的愈伤过程

二氧化氯（ClO2）是一种安全高效的消毒剂,广泛用于果蔬保鲜和疾病的防治,但ClO2处理对马铃薯采后块茎的愈伤效果尚不明确。本研究采用25 mg/L ClO2浸泡切半‘大西洋’马铃薯块茎10 min,然后于室温黑暗条件下愈伤0、3、5、7、14、21 d。测定损伤块茎在愈伤期间的质量损失率以及损伤接种硫色镰刀菌（Fusarium sulphureum）块茎的病情指数,观察伤口处聚酚软木脂和木质素的积累,测定伤口处苯丙烷代谢关键酶和过氧化物酶活力,以及苯丙烷代谢产物和H2O2的含量。结果表明,25 mg/L ClO2处理加速了聚酚软木酯和木质素的沉积,增加了愈伤期间损伤组织的细胞层厚度。此外,ClO2处理降低了损伤块茎的质量损失率以及损伤接种硫色镰刀菌（F. sulphureum）后块茎的病情指数,第14天时,处理块茎的质量损失率和病情指数分别低于对照20.8%和45.3%。另外,ClO2处理通过提高块茎伤口组织处苯丙氨酸解氨酶、肉桂酸-4-羟化酶与肉桂醇脱氢酶的活力,增加了5 种酚酸（肉桂酸、p-香豆酸、咖啡酸、阿魏酸和芥子酸）及3 种木质素单体（p-香豆醇、芥子醇和松柏醇）的含量;ClO2处理还显著促进了总酚、类黄酮和木质素的合成,提高了H2O2含量和过氧化物酶（peroxidase,POD）活力。综上所述,ClO2处理加速了愈伤期间马铃薯损伤块茎伤口处聚酚软木酯、木质素的沉积,降低了损伤块茎的质量损失率及病情指数,激活了苯丙烷代谢,提高了H2O2含量和POD活力。这些发现为ClO2处理加速马铃薯块茎的愈伤提供了理论依据。     

Protein kinase C activity mediates LH-induced ErbB/Erk signaling in differentiated hen granulosa cells

While there is accumulating evidence that mitogen-activated protein kinase/Erk and protein kinase C (PKC) signaling inhibits premature differentiation of granulosa cells in hen prehierarchal follicles, it has only recently been established that these signaling pathways play an important facilitory role in promoting steroidogenesis in differentiated granulosa cells from preovulatory follicles. The present studies were conducted with differentiated granulosa cells to establish the ability of LH to initiate PKC activity, and the subsequent requirement for PKC activity in promoting the ErbB/Erk signaling cascade that ultimately facilitates LH-induced progesterone production. Incubation of differentiated granulosa cells with LH increases PKC activity within 15 min, and latently promotes Erk phosphorylation (P-Erk) by 180 min. Inhibition of PKC activity with GF109203X attenuates LH- and 8-bromo-cAMP (8-br-cAMP)-induced P-Erk, but not P-Erk promoted by an epidermal growth factor (EGF) family ligand (e.g., transforming growth factor alpha). Importantly, inhibition of PKC activity also blocks the LH-induced increase in the autocrine expression of mRNA encoding the EGF family ligands, such as EGF, amphiregulin, and betacellulin. Furthermore, inhibition of EGF ligand shedding at the level of the cell membrane using the matrix metalloprotease activity inhibitor, GM6001, prevents both LH- and 8-br-cAMP-induced P-Erk and progesterone production. These findings provide evidence for a facilitory role of PKC and ErbB/Erk signaling in LH-induced progesterone production, place the requirement for PKC activation upstream of ErbB/Erk activity, and demonstrate for the first time in a non-mammalian vertebrate the requirement for PKC activity in LH-induced expression of EGF family ligands in granulosa cells.     

The cleavage energy at initiation of (110) silicon

We evaluated the cleavage energy at initiation of the (110)[1 $\bar{{1}}$ 0] low energy cleavage system of silicon crystal under pure Mode I, at room conditions and under inert argon gas at atmospheric pressure. The results revealed significant reduction of the room cleavage energy, presumably due to the effect of environmental molecules at the crack front. We also show that misalignment between the precrack and the maximum $G_{I}$ plane yields large variations in the cleavage energy, which may explain the large discrepancy appearing in the literature. Comparison of our results with those existing in the literature, enabled conclusion regarding the lower limit of the cleavage energy at initiation of brittle crystals and comments on other physical effects associated with crack initiation in these materials. We describe in details the experimental method that was used to evaluate the cleavage energy at initiation. This method is aimed at cleaving brittle materials in a controllable and noiseless manner and to generate high resolution fracture experiments. It consists in gluing a thin, precracked, rectangular brittle specimen in a rectangular aluminum frame, using thin layers of epoxy resin. Being very complaint, these layers enable to reduce the energy flow to the crack tip and to manipulate crack speed for accurate evaluation of materials properties. Crack initiation, propagation, and arrest, when needed, occur upon heating the assembly by only a few $^{\circ }\hbox {C}$ , due to the coefficients of thermal expansion mismatch between the specimen and the aluminum frame. Among other advantages, it facilitates accurate evaluation of fracture properties of brittle crystals, through utilizing the assembly as a boundary value problem appropriate for finite element analysis without requiring any assumptions regarding boundary conditions.     

Tracing long-term effects of early trauma: A broad-scope view of Holocaust survivors in late life.

This study addressed long-term effects of extreme trauma among Holocaust survivors (N=126) in an older (75-94 years) sample of the Israeli Jewish population. Survivors were compared with European-descent groups that had immigrated either before World War II (n=206) or after (n=145). Participants in the latter group had had Holocaust-related life histories but did not consider themselves survivors. Controlling for sociodemographics, the results indicated that survivors fared worse than prewar immigrants in certain psychosocial domains, mainly cumulative distress and activity, rather than in health-related ones. Survivors and postwar immigrant comparisons had almost no differences. The study highlights the need for a wide view of functioning facets and comparison groups in delineating late posttraumatic effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Solid-Phase Epitaxy of Thin Silicon Film on Si(111) Surface Studied by Scanning Tunneling Microscopy

Solid-phase epitaxy (SPE) of thin silicon film with a thickness of 0.2–2 bilayers (BL) on Si(111)-(7 × 7) surface was studied by scanning tunneling microscopy. At small coverage, the SPE growth proceeds via coarsening of islands. As the coverage exceeds the percolation threshold, a ‘mirror’ process consisting of coarsening of voids in the continuous layer takes place. The SPE growth of a thicker continuous layer results in a partly disordered flat surface, displaying a mixture of different reconstructions. Quantitative characterization of this surface by the formalism of pair distribution functions reveals an anisotropy in the orientational order that may indicate that SPE occurs preferably in the step direction. A possibility to use an SPE-grown layer as a two-dimensional model for bulk processes in solids is discussed.     

Beyond keeping active: Concomitants of being a volunteer in old-old age.

This study examines concomitants of volunteering in the context of other lifestyle activities. Investigating formal volunteering in old-old age, the authors analyzed data of 148 volunteers versus 1,195 nonvolunteers in a national sample of the Israeli Jewish population aged 75-94. As hypothesized, being a volunteer related (whether as a cause or effect) to more positive functioning on psychosocial markers and prospectively resulted in reduced mortality risk even when other activity outlets (physical activity, everyday activities, having a hobby) were controlled. These findings suggest that the benefits of volunteering in late life are not reducible to those of other activities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)