如何让硬件发挥最大功效？

对于我们而言，绝大多数人都想从身边的硬件设备，或其他应用中获得最大功效，例如，台式电脑、手机、无线网络和其他设备。而在我们接下来的这篇文章中，我们将手把手教大家如何让科技设备运行得更快，变得更具功效，变得更加通用。     

The impact of the Internet on the social lives of users: A representative sample from 13 countries

One of the most vociferous criticisms of the Internet has always been that it contributes to loneliness among its users. This study analyses results from the World Internet Project, comprised of representative samples from 13 countries (22,002 participants). Thus creating an exceptional international representative sample. In analyzing those results, we argue that in order to achieve a comprehensive understanding of the Internet’s influence over individuals’ social lives; it is essential to consider the different types of social connections that might be influenced by the Internet. We assess the influence of Internet use over social interactions in separate life domains (e.g. with family members; friends; colleagues). Our analysis confirms that Internet usage can actually enhance the social lives of its users. Qualifications to the research are discussed while highlighting the different life domains in which we found significant correlations between Internet usage and increased social interactions.     

RCS: a reference model architecture for intelligent control

The real-time control system (RCS), a reference model architecture for intelligent real-time control systems, is described. It partitions the control problem into four basic elements: task decomposition, world modeling, sensory processing and value judgment. RCS clusters these elements into computational nodes that control specific subsystems, and arranges these nodes in hierarchical layers so that each layer has characteristic functionality and timing. The RCS architecture has a systematic regularity and recursive structure that suggests a canonical form. Four versions of RCS have been developed. The application of one of the versions to machining workstation consisting of a part buffer, a machine tool and a robot is examined. The functionality of each of the levels in the control hierarchy is discussed     

Light responsiveness of the suprachiasmatic nucleus: long-term multiunit and single-unit recordings in freely moving rats

The suprachiasmatic nuclei (SCN) of the hypothalamus contain a pacemaker that generates circadian rhythms in many functions. Light is the most important stimulus that synchronizes the circadian pacemaker to the environmental cycle. In this paper we have characterized the baseline neuronal firing patterns of the SCN as well as their response to light in freely moving rats. Multiunit and single-unit recordings showed that SCN neurons increase discharge during daytime and decrease discharge at night. Discharge levels of individual neurons that were followed throughout the circadian cycle appeared in phase with the population and were characterized by low discharge rates (often below 1 Hz), with a twofold increase during the day. The effect of light on the multiunit response was dependent on the duration of light exposure and on light intensity, with light thresholds of approximately 0.1 lux. The light response level showed a strong dependency on time of day, with large responsiveness at night and low responsiveness during day. At both phases of the circadian cycle, the response level could be raised by an increase in light intensity. Single-unit measurements revealed that the time-dependent light response of SCN neurons was present also at the level of single units. The results show that the basic light response characteristics that were observed at the multiunit level result from an integrated response of similarly behaving single units. Research at the single-unit level is therefore a useful approach for investigating the basic principles of photic entrainment.     

Transcriptional regulation of cellular retinaldehyde-binding protein in the retinal pigment epithelium. A role for the photoreceptor consensus element

Cellular retinaldehyde-binding protein (CRALBP) is abundantly expressed in the retinal pigment epithelium (RPE) and Muller cells of the retina, where it is thought to function in retinoid metabolism and visual pigment regeneration. Mutations in human CRALBP that destroy retinoid binding have been linked to autosomal recessive retinitis pigmentosa. To identify the DNA elements that regulate expression of the human CRALBP gene in the RPE, transient transfection studies were carried out with three CRALBP-expressing human RPE cell culture systems. The regions from -2089 to -1539 base pairs and from -243 to +80 base pairs demonstrated positive regulatory activity. Similar activity was not observed with cultured human breast, liver, or skin cells. Since sequence analysis of the -243 to +80 region identified the presence of two photoreceptor consensus element-1 (PCE-1) sites, elements that have been implicated in photoreceptor gene regulation, the role of these sequences in RPE expression was examined. Mutation of either PCE-1 site significantly reduced reporter activity, and mutation or deletion of both sites dramatically reduced activity. Electrophoretic mobility shift analysis with RPE nuclear extracts revealed two complexes that required intact PCE-1 sites. These studies also identified two identical sequences (GCAGGA) flanking PCE-1, termed the binding CRALBP element (BCE), that are also important for complex formation. Southwestern analysis with PCE-1/BCEcontaining probes identified species with apparent masses near 90-100 and 31 kDa. These results begin to identify the regulatory regions required for RPE expression of CRALBP and suggest that PCE-1-binding factor(s) may play a role in regulating RPE as well as photoreceptor gene expression.     

Basic fibroblast growth factor is neither necessary nor sufficient for the development of retinal neovascularization

Basic fibroblast growth factor (FGF2) is constitutively expressed in the retina and its expression is increased by a number of insults, but its role in the retina is still uncertain. This study was designed to test the hypothesis that altered expression of FGF2 in the retina affects the development of retinal neovascularization. Mice with targeted disruption of the Fgf2 gene had no detectable expression of FGF2 in the retina by Western blot, but retinal vessels were not different in appearance or total area from wild-type mice. When FGF2-deficient mice were compared with wild-type mice in a murine model of oxygen-induced ischemic retinopathy, they developed the same amount of retinal neovascularization. Transgenic mice with a rhodopsin promoter/Fgf2 gene fusion expressed high levels of FGF2 in retinal photoreceptors but developed no retinal neovascularization or other abnormalities of retinal vessels; in the ischemic retinopathy model, they showed no significant difference in the amount of retinal neovascularization compared with wild-type mice. These data indicate that FGF2 expression is not necessary nor sufficient for the development of retinal neovascularization. This suggests that agents that specifically antagonize FGF2 are not likely to be useful adjuncts in the treatment of retinal neovascularization and therapies designed to increase FGF2 expression are not likely to be complicated by retinal neovascularization.     

Behavioral tolerance and sensitization to alcohol in humans: The contribution of learning.

This experiment tested the hypothesis that tolerance or sensitization to repeated alcohol doses is predicted by the particular response (diminished or augmented impairment) that is reinforced under drug. Twelve male social drinkers were assigned to a tolerance (T) or sensitization (S) group (n?=?6) and performed a psychomotor task under 0.62 g/kg of alcohol on 5 separate sessions. The 1st session preceded training and determined that the groups' drugged performance did not differ. On 3 subsequent sessions verbal feedback reinforced diminished impairment in Group T and augmented impairment in Group S. During these sessions, Groups T and S displayed tolerance and sensitization, respectively. The final session showed that training effects were retained without reinforcement. The results extend the evidence on the effect of reinforcement to show that it can enhance sensitization as well as tolerance. The findings demonstrate that behavioral variables modulate the response to alcohol and imply that tolerance and sensitization may be affected by a common learning process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetic relationship between dopamine transporter gene and schizophrenia: linkage and association

This experiment was aimed at comparing the sensorimotor correlates of fimbria-fornix lesions made with either a classical aspiration technique that also removes part of the overlying cortical structures, or an electrolytic one that does not encroach upon these cortical structures. About 4 months after lesion surgery, Long-Evans female rats which had sustained an aspiration or an electrolytic fimbria-fornix lesion at the age of 90 days were tested to measure their beam-walking performance as an index for their sensorimotor capabilities. We found that after an aspiration lesion, the rats presented sensorimotor deficits which did not occur after an electrolytic lesion. After having found that electrolytic lesions of the fimbria and the fornix produced neurochemical deficits (in the dorsal hippocampus) and cognitive alterations close to those resulting from aspiration lesions, it is concluded from the present experiment that the electrolytic lesion technique is an interesting alternative to an aspiration technique, essentially because the former does not induce the sensorimotor deficits due to the partial damage that an aspiration technique produces in the medial parietal cortex. As the electrolytic lesion technique may minimize the risk of introducing a sensorimotor bias in the accuracy of cognitive evaluations, the present result might be of interest to neuroscientist using a fimbria-fornix lesion paradigm in order to investigate the efficacy of drugs, grafts or other treatments on the recovery from cognitive deficits.     

CONCENTRATION FORCING IN AMMONIA SYNTHESIS: PLUG-FLOW EXPERIMENTS AT HIGH TEMPERATURE AND PRESSURE

Square-wave concentration forcing experiments have been performed for the ammonia synthesis reaction in an isothermal, fixed-bed, plug-flow reactor at a temperature and pressure approaching industrial conditions (703 K, 4.14Mpa). Using the optimal steady-state (OSS) production rate as a base for comparison, we have found that cycling between pure reactants (N₂, H₂) results in decreased time-averaged production rates as predicted by Wilson and Rinker (1982), while mixture cycling under appropriate conditions results in modest (but not insignificant) improvements over the OSS rate. We also have observed that the catalyst activity changes significantly under a variety of dynamic operating conditions.