Shrinking network development time-scales: flexible virtualnetworks

A new type of virtual network is presented which allows the virtual network owner to exert control over their network resources in a completely flexible fashion. These virtual networks use a technique known as `switchlets', which result from partitioning the resources, both physical and logical, of a switch. Each partition is a switchlet. Switchlets from different physical switches may be interconnected together in a manner consistent with the physical connectivity of the real switches. Each set of interconnected switchlets can be controlled by its own system, called a `control architecture'. Such an arrangement results in a set of virtual networks, each with its own control architecture. These control architectures may be identical, that is they may be different instances of the same control architecture, or they may be radically different. This paper examines how switchlets can be used to provide functionality which is either impossible or problematic to provide using conventional approaches to network control     

Geographical problems of allocation in the Soviet fuel supply

This article examines the major problems facing Soviet planners in meeting fuel demand for boiler and furance uses in the USSR — the most flexible sector of the energy economy where direct substitution among energy sources is technically and economically at its most feasible. Data limitations and the interdependent nature of the whole fuel economy make the consistent rigid separation of this sector impossible and unprofitable. Accordingly, some attention is given to the fuel mix as a whole and to aggregate energy projections and questions of policy. (Coke is not covered.)     

Milk urea testing as a tool to monitor reproductive performance in Ontario dairy herds.

Dairy herd improvement test-day data, including milk urea concentrations measured using infrared test method, were collected from 60 commercial Ontario Holstein dairy herds for a 13-mo period between December 1, 1995, and December 31, 1996. The objective of the study was to describe, at the cow and the group level, the relationship between DHI milk urea concentrations and reproductive performance in commercial dairy herds. When interpreted at the cow level, there was no association between milk urea and the risk for pregnancy from an insemination occurring within the 45-d period preceding test day. However, a negative curvilinear relationship existed between milk urea and the risk for pregnancy from a first, second, or third insemination event occurring within the 45-d period following test day, with the odds for pregnancy being highest when the milk urea on the test day preceding the insemination was either below 4.5 mmol/L or greater than 6.49 mmol/L, compared with a concentration between 4.5 and 6.49 mmol/L. When interpreted at the group level, there was no association between group mean milk urea for cows between 50 and 180 DIM, and the group conception rate for cows receiving a first, second, or third insemination event in the 45-d period either preceding or following test day. Thus, while DHI milk urea measurements may be useful as a management tool to improve the efficiency of production or reduce nitrogen excretion, through helping to optimize the efficiency of protein utilization, they may have limited utility as a monitoring or diagnostic tool for reproductive performance. The results of this study suggest that good fertility may be achieved across a broad range of milk urea concentrations.     

The effectiveness of play therapy: Responding to the critics.

Notes that play therapy has long been criticized for a lack of adequate research base to prove its efficacy. For 6 decades, while play therapists conducted small research studies, critics challenged the utility and efficacy of play therapy as a viable psychotherapy intervention. The purpose of this study was to conduct a meta-analysis of 94 research studies focusing on the efficacy of play therapy, filial therapy, and combined play therapy and filial therapy. The following electronic databases were used in the authors 3-yr search for studies on play therapy: PsycLit, PsycINFO, ERIC, FirstSearch, and Dissertation Abstracts. Meta-analysis revealed a large positive effect on treatment outcomes with children. Play therapy appeared effective across modality, age, gender, clinical vs nonclinical populations, setting, and theoretical schools of thought. Additionally, positive play therapy effects were found to be greatest when there was parent involvement in treatment and an optimal number of sessions provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The impact of familial alcoholism on alcohol reactivity in female social drinkers.

Some individuals may have an inherent reactivity to alcohol that facilitates early development of characteristics associated with alcoholism. Although response to alcohol cues has been used to assess this reactivity, few studies have included women or investigated familial alcoholism as a variable. In this study, 23 female college students were divided into groups according to family history of alcoholism (positive or negative). Alcohol reactivity was measured by salivation, skin temperature, heart rate, mood state, and craving for alcohol following presentation of alcohol-related and neutral cues. Results indicate no correlation between salivary reactivity and alcohol craving, which suggests that these variables tap into different domains of cue reactivity. Findings demonstrate that alcohol cue reactivity can be assessed in female social drinkers and that familial alcoholism may influence salivary reactivity to alcohol-related cues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dopamine release in the medial preoptic area of female rats in response to hormonal manipulation and sexual activity.

Dopamine (DA) is responsive to hormonal manipulations and has been implicated in the regulation of female rat sexual behavior. In the present studies, extracellular DA levels were assessed in the medial preoptic area (MPOA) of ovariectomized female rats in response to exogenous ovarian hormones and during sexual activity. In female rats primed with a low dose of estradiol benzoate (2 μg), but not with a higher dose (20 μg), a 500-μg progesterone injection increased extracellular DA and facilitated copulatory behavior. Extracellular DA levels in the MPOA were further augmented during sexual interactions with a male rat in a nonpacing copulatory chamber by either perineal or vaginal stimulation. However, in a pacing chamber, DA efflux did not increase, although the metabolites rose significantly during copulation. Together, these findings suggest that extracellular DA in the MPOA responds to the hormonal state of the female rat and may contribute to her expression of sexual behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Metabolic predictors of displaced abomasum in dairy cattle

The objective of this field study was to identify metabolic tests available in clinical practice that identified cows at increased risk of left displaced abomasum (LDA). A technician visited 1044 cows in 20 herds weekly from 1 wk before expected calving until 1 wk postpartum. Cows were assigned a body condition score and samples were collected at each visit for measurement of serum nonesterified fatty acids (NEFA), cholesterol, beta-hydroxybutyrate (BHBA), glucose, urea, calcium, and phosphorus, and a milk sample was collected postpartum for measurement of BHBA. The probability of LDA was modeled with multivariable logistic regression accounting for clustering. There were 53 cases of LDA (incidence risk = 5.1%) and the median time of diagnosis was 11 d in milk. In cows with LDA, mean NEFA concentrations began to diverge from the mean in cows without LDA 14 d before calving, whereas mean serum BHBA concentrations did not diverge until the day of calving. Prepartum, only NEFA concentration was associated with risk of subsequent LDA. Between 0 and 6 d before calving, cows with NEFA concentration > or =0.5 mEq/L were 3.6 times more likely to develop LDA after calving. For prospective application, among samples taken 4 to 10 d before expected calving, the optimum NEFA cut-point remained 0.5 mEq/L. The sensitivity, specificity, and likelihood ratio (LR) were 46%, 82%, and 2.6, respectively. Between 1 and 7 d postpartum, retained placenta, metritis, and increasing serum concentrations of BHBA and NEFA were associated with increased risk of subsequent LDA. However, considered separately, postpartum serum BHBA was a more sensitive and specific test than NEFA concentration. The odds of LDA were 8 times greater in cows with serum BHBA > or =1200 micromol/L (LR = 3.5). Cows with milk BHBA concentration > or =200 micromol/L were 3.4 times more likely to develop LDA. Serum calcium concentration was not associated with LDA. Strategic use of metabolic tests to monitor transition dairy cows should focus on NEFA in the last week prepartum and BHBA in the first week postpartum.     

Oriented mesoporous organosilicate thin films

Coassemblies of block copolymers and inorganic precursors offer a path to ordered inorganic nanostructures. In thin films, these materials combined with domain alignment provide highly robust nanoscopic templates. We report a simple path to control the morphology, scaling, and orientation of ordered mesopores in organosilicate thin films through the coassembly of a diblock copolymer, poly(styrene-b-ethylene oxide) (PS-b-PEO), and an oligomeric organosilicate precursor that is selectively miscible with PEO. Continuous films containing cylindrical or spherical pores are generated by varying the mixing composition of symmetric PS-b-PEO and an organosilicate precursor. Tuning interfacial energy at both air/film and film/substrate interfaces allows the control of cylindrical pore orientation normal to the supported film surfaces. Our method provides well-ordered mesoporous structures within organosilicate thin films that find broad applications as highly stable nanotemplates.     

Visual Awareness and the Detection of Fearful Faces.

A commonly held view is that emotional stimuli are processed independently of awareness. Here, the authors parametrically varied the duration of a fearful face target stimulus that was backward masked by a neutral face. The authors evaluated awareness by characterizing behavioral performance using receiver operating characteristic curves from signal detection theory. Their main finding was that no universal objective awareness threshold exists for fear perception. Although several subjects displayed a behavioral pattern consistent with previous reports (i.e., targets masked at 33 ms), a considerable percentage of their subjects (64%) were capable of reliably detecting 33-ms targets. Their findings suggest that considerable information is available even in briefly presented stimuli (possibly as short as 17 ms) to support masked fear detection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Teamwork in Multiteam Systems.

The authors examined how networks of teams integrate their efforts to succeed collectively. They proposed that integration processes used to align efforts among multiple teams are important predictors of multiteam performance. The authors used a multiteam system (MTS) simulation to assess how both cross-team and within-team processes relate to MTS performance over multiple performance episodes that differed in terms of required interdependence levels. They found that cross-team processes predicted MTS performance beyond that accounted for by within-team processes. Further, cross-team processes were more important for MTS effectiveness when there were high cross-team interdependence demands as compared with situations in which teams could work more independently. Results are discussed in terms of extending theory and applications from teams to multiteam systems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)