Monitoring soil CO2 respiration with chamber measurements and identifying controlling factors such as the diversity of vegetation species, moisture and temperature can help guide desert scrubland management. Soil CO2 respiration and potential controlling factors at four sites in desert scrubland were examined along the Sangong River Basin (SRB) in northwestern China in 2004. Soil CO2 respiration descended along the SRB as did the diversity of vegetation species, air temperature and air humidity. The two sites of the field station (FS) and the north desert (ND) and the low reaches of the SRB among these locations were monitored to analyze the effects of pH value, soil organic carbon (SOC), total nitrogen (TN) and calcium carbonate (CaCO3) on soil CO2 respiration during the growing season in 2005. The ND site was located at the southern edge of the Gurbantunggut Desert; the FS site was in the border area of the SRB Alluvial Fan. One-way ANOVA was performed. The result showed that air humidity and CaCO3 content had a strong influence on soil CO2 respiration; SOC content was a limitation to soil CO2 respiration in the arid-desert zone. Effective management activities can attenuate soil CO2 respiration and keep carbon balance trends at a desirabe level in desert scrublands.

In the general discussion of double auction, three properties are mainly considered: incentive compatibility, budget balance, and economic efficiency. In this paper, we introduce another property of double auction: semi-independence, from which we are trying to reveal the essential relation between incentive compatibility and economic efficiency. Babaioff and Nisan [[1]] studied supply chain of markets and corresponding protocols that solve the transaction and price issues in markets chain. In the second part of the paper, we extend their model to two-level markets, in which all markets in the supply chain are independent and controlled by different owners. Beyond this basic markets chain, there is a communication network (among all owners and another global manager) that instructs the transaction and price issues of the basic markets. Then we discuss incentive compatible problems of owners in the middle level of the markets in terms of semi-independence.

The concepts of object and class have limitations in many situations, such as where inheritance does not offer natural solutions and design patterns have to be applied at a cost to polymorphism, extendibility and software reusability. Proposals have been advanced to generalize the concepts of object and class, such as in Active Oberon. We adapt the concept of agents to software engineering, propose a new concept called caste ? a sort of ‘dynamic class’ of agents, and examine how it helps solve common problems in object orientation.

As a baseline for software development, a correct and complete requirements definition is one foundation of software quality. Previously, a novel approach to static testing of software requirements was proposed in which requirements definitions are tested on a set of task scenarios by examining software behaviour in each scenario described by an activity list. Such descriptions of software behaviour can be generated automatically from requirements models. This paper investigates various testing methods for selecting test scenarios. Data flow, state transition and entity testing methods are studied. A variety of test adequacy criteria and their combinations are formally defined and the subsume relations between the criteria are proved. Empirical studies of the testing methods and the construction of a prototype testing tool are reported

How to specify agent’s intelligent behaviour is a challenging open problem in the development of agent-based systems. This paper presents a case study of developing the formal specification of the evolutionary multi-agent ecosystem Amalthaea developed at MIT Media Lab. A diagrammatic notation is used for the development of agent models and to derive a formal specification of the system in SLABS, which is a formal specification language for agent-based systems.

Abstract In the adult brain, neurogenic stem cells are prevalent in the subventricular zone (SVZ) of the lateral ventricle wall and the subgranular zone (SGZ) in the dentate gyrus. Cells that have structural and molecular characteristics of astrocytes function as neurogenic stem cells in these regions, in which these cells also participate in the creation of the microenvironment that stimulates neurogenesis. In the present paper, we review the phenotypic properties, subpopulations, and proliferation of glial fibrillary acidic protein (GFAP)-expressing cells in these two neurogenic regions and their responses to different brain injuries. Cells fulfilling the criteria for astrocytes, i.e., expressing GFAP, in the SVZ and SGZ respond differently to brain injuries or neurogenic stimuli. The importance of guidance by astrocytes of newly formed neuronal cells is emphasized. The assessment of GFAP-expressing cells in the neurogenic regions is of great importance for understanding the mechanism underlying the response of neural stem cells to brain injury. © 2007 Wiley-Liss, Inc.

Proliferating cells are hardly detectable in the adult mammalian brain by microscopy of stained sections, but after pre-labeling with radioactive thymidine or 5'-bromo-2-deoxyuridine (BrdU), either marks the nucleus, as do mitosis-related proteins such as Ki67 and PCNA. Engineered virus may also be used to mark proliferating cells. One alternative approach is to use the enzyme ribonucleotide reductase (RNR), expressed by proliferating cells, but not by quiescent ones. A monoclonal antibody against the M1 subunit of RNR was used to visualize proliferating cells in the brains of adult normal rats, rabbits, pigs and sheep. Stem cells were distinctly outlined. In the subgranular layer in the hippocampal dentate gyrus, most RNR immunoreactive cells were bipolar to multipolar, and had a large cell body and long processes. Two different populations of RNR expressing cells were visualized in the subventricular zone in the forebrain, one dominated by small, bipolar cells extending into the rostral migratory stream, while the other was formed by large multipolar cells, adjacent to the ependyma, with processes extending to the lateral ventricle. Furthermore, rare RNR-expressing cells were recognized throughout the brain. The RNR immunoreactive cells were immature, as they did not express any marker characterizing differentiated neurons and glial cells, except for a fraction that co-expressed the gliofibrillary acidic protein. BrdU and RNR were co-localized in proliferating cells in animals pretreated with BrdU. We conclude that RNR immunohistochemistry can accurately visualize proliferating cells, including stem cells, in adult mammalian brains. The occurrence of processes at cell proliferation is elucidated. Further, the advocated approach does not require any pre-labeling, and can be carried out on fixed tissues.

A network monitoring device includes a flow processing element, disposed to receive flow information relating to network flows, and to generate a set of virtual packets, each representing a portion of a network flow. The virtual packets are maintained in a time-sequential order, and read by elements of the network monitoring device to generate information relating to network traffic, such as symptoms affecting the communication network, problems affecting the communication network, and otherwise. The network monitoring device randomly samples virtual packets, with at least one of two effects: (1) flow information from traffic reporting devices that are themselves sampling a differing rates can be equalized, with the effect of standardizing information from all of them; (2) the network monitoring device itself can restrict its attention to a fraction of all virtual packets, with the effect of keeping up with a relatively large number of virtual packets.

We study the unbounded batch machine scheduling of n jobs to minimize the total completion time.A batch machine can handle up to B ≥ n jobs simultaneously.Eac h job is characterized by a release(arrival) time and a processing time.J obs processed in the same batch have the same completion time.(i.e., their common starting time plus the processing time of the longest job in the batch.) For batch processing, nonpreemptive scheduling is usually required and we focus on this case.I n this paper, we establish a polynomial time approximation scheme for it.

Nuclear factor E2-related factor 2 (Nrf2) is a critical regulator of cytoprotective gene expression. However, the role of this transcription factor in myocardiac cytoprotection against oxidative and electrophilic stress remains unknown. This study was undertaken to investigate if Nrf2 signaling could control the constitutive and inducible expression of antioxidants and phase 2 enzymes in primary cardiomyocytes as well as the susceptibility of these cells to oxidative and electrophilic injury. The basal expression of a series of antioxidants and phase 2 enzymes was significantly lower in cardiomyocytes from Nrf2(-/-) mice than those from wild-type littermates. Incubation of wild-type cardiomyocytes with 3H-1,2-dithiole-3-thione (D3T) led to significant induction of various antioxidants and phase 2 enzymes, including catalase, glutathione, glutathione peroxidase (GPx), glutathione reductase, glutathione S-transferase, NAD(P)H:quinone oxidoreductase 1, and heme oxygenase-1. The inducibility of the above cellular defenses except GPx by D3T was abolished in Nrf2(-/-) cardiomyocytes. As compared to wild-type cells, Nrf2(-/-) cardiomyocytes were much more susceptible to cell injury induced by H2O2, peroxynitrite, and 4-hydroxy-2-nonenal. Treatment of wild-type cardiomyocytes with D3T, which upregulated the cellular defenses, resulted in increased resistance to the above oxidant- and electrophile-induced cell injury, whereas D3T treatment of Nrf2(-/-) cardiomyocytes provided no cytoprotection. This study demonstrates that Nrf2 is an important factor in controlling both constitutive and inducible expression of a wide spectrum of antioxidants and phase 2 enzymes in cardiomyocytes and is responsible for protecting these cells against oxidative and electrophilic stress. These findings also implicate Nrf2 as an important signaling molecule for myocardiac cytoprotection.

Aqueous extracts of fresh leaves and organic soil of northern sheep laurel (Kalmia angustifolia var. angustifolia) were found to be inhibitory to the growth of black spruce (Picea mariana) germinants. Primary root growth of black spruce was more affected by the extracts than was shoot growth. The growth inhibition caused by the leaf extract was most pronounced under acidic conditions (pH 3-4). The aqueous extract of Kalmia leaves contained ferulic, vanillic, syringic, gentisic, m-coumaric, p-coumaric, o-hydroxyphenylacetic, and p-hydroxybenzoic acids as well as some other unknown compounds. These compounds were isolated from the aqueous extract of Kalmia leaves by ethyl acetate extraction and identified using thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). Bioassay indicated that the overall toxicity of the phenolic compounds to black spruce appeared to increase in the order of o-hydroxyphenylacetic, p-hydroxybenzoic, vanillic, p-coumaric, gentisic, syringic, ferulic, and m-coumaric acids.