Temporary Resources Research Articles

The effect of fatigue on the attentional blink

Published online: 11 July 2013(Q> Psychonomic Society, Inc. 2013It has been suggested that attention and emotional states are tightly linked, in that negative moods are associated with narrowed attentional focus, whereas positive moods are asso- ciated with broadened focus. However, recent studies on the effect of affective states, using the attentional blink deficit as a reflection of the temporary unavailability of attentional re- sources, have reported ambiguous results regarding the deploy- ment of attention in the temporal domain. In the present study, we examined whether the effect of affective state on the atten- tional blink should be interpreted in terms of valence and arousal axes or in terms of the specificity of the connection between affect and attention. We chose to use fatigue to test these alternatives because, according to the two-axis view, fatigue would not be expected to increase the attentional blink. Participants identified two targets embedded in a stream of nontargets, and for half of the participants, a state of fatigue was induced using the Trier Social Stress Test. Those in the experimental group demonstrated a greater attentional blink relative to those in the control group, who did not receive the mood manipulation. The results suggest unique links between mood states and attention during a task involving temporal selection.Studies in cognitive psychology have shown that the de- ployment of attentional resources (Kahneman, 1973; Matthews & Desmond, 1998) is determined by various external factors, such as physically (Theeuwes, 2010) and socially (West, Anderson, & Pratt, 2009) distinctive items, as well as by endogenous factors, such as intention (Hommel, 2010). Moreover, the deployment of attention can also be affected by such internal factors as motivation (Delia Libera & Chelazzi, 2006) and the current mood state (Fredrickson, 2004; Friedman & Forster, 2010), because the internal states of observers can influence executive function (Ashby, Isen, & Turken, 1999), which governs the major cognitive systems, thereby including the deployment of attention.In terms of the spatial domain, it is generally agreed that negative moods are associated with narrowed attentional focus, whereas positive moods are associated with broad- ened focus (Rowe, Hirsh, & Anderson, 2007). Therefore, in a typical Eriksen flanker task, in which observers identify a target, the flanking distractors interfered less when partici- pants were in a negative than when they were in a neutral mood (Sato, Takenaka, & Kawahara, 2012). In contrast, broadened and more distributed attention is more likely in positive than in neutral moods (Moriya & Nittono, 2011).Such effects of mood states can also be demonstrated in the temporal domain by using the attentional blink task (Raymond, Shapiro, & Arnell, 1992), in which identification of the second of two targets embedded in a rapid stream of nontargets is impaired at short intertarget lags (about 100- 300 ms). This impairment has been attributed to the unavailability of temporary attentional resources immediate- ly after processing of the first target. Recently, MacLean, Arnell, and Busseri (2010) demonstrated that higher levels of self-reported negative trait affect were associated with a greater attentional blink. These researchers also found that the magnitude of the attentional blink was negatively corre- lated with trait positive affect and that negative affect was more strongly correlated with the attentional blink than was positive affect, suggesting that negative affect is not simply the absence of positive affect, but rather appears to have its own impact. Moreover, MacLean and Arnell (2010) found that greater dispositional positive affect was associated with a smaller attentional blink, whereas greater negative trait affect was associated with a larger attentional blink (see also Rokke, Arnell, Koch, & Andrews, 2002, for a similar finding related to depression). …

Feeding strategy of the non‐native rainbow trout,Oncorhynchus mykiss, in low‐orderPatagonian streams

AbstractThe dietary composition and feeding strategy of rainbow trout,Oncorhynchus mykiss(Walbaum), in two low‐order Patagonian streams were studied. Benthic macroinvertebrate availability was estimated in both riffles and pools. Fish stomach contents were examined to determine prey richness and diversity, prey electivity, food‐niche width, and the feeding strategy employed by trout throughout the year. Availability of benthos varied seasonally with Ephemeroptera, Trichoptera, Plecoptera and Diptera species dominating. Rainbow trout diet was composed mainly of benthic macroinvertebrates, followed by terrestrial insects, fish, algae and plants. Different trout size classes segregated the use of food resources to reduce predation pressure. Elected prey included organisms displaying no to high mobility. A high feeding plasticity allows trout to buffer changes in food availability by switching from a specialised to a generalised feeding behaviour. Consequently, trout may exploit abundant but temporary food resources opportunistically, which would explain their marked expansion in Patagonian environments.

The Application of Cloud Computing in Virtual Enterprise’s Information Resources Sharing

With the rapid development of social,science and technology ,we are always looking for the advanced and rapid manufacturing method and the management pattern.thus a new enterprise cooperation pattern-Virtual Enterprise arises at the historic moment. The cooperation is a process which advantages the temporary enterprise resources each other. Therefore, the virtual enterprise must encounter the problem that how to realize the virtual enterprises’ information resources sharing and improve the efficiency of enterprise cooperation. This paper uses the cloud computing’s advantage to solve the problem of virtual enterprise information resources sharing. Then enterprise is able to share the information of different regions,different computing environment and improve the efficiency of virtual enterprise cooperation.

Virtual prototyping for planning bridge construction

Abstract 4D simulation, building information modeling, virtual construction, computer simulation and virtual prototyping are emerging topics in the building construction industry. These techniques not only relate to the buildings themselves, but can also be applied to other forms of construction, including bridges. Since bridge construction is a complex process involving multiple types of plant and equipment, applying such virtual methods benefits the understanding of all parties in construction practice. This paper describes the relationship between temporary platforms, plant and equipment resources and a proposed-built model in the construction planning and use of Virtual Prototyping Simulation (VPS) to implement different construction scenarios in order to help planners identify an optimal construction plan. A case study demonstrates the use of VPS integrated with temporary platform design and plant and equipment-resource allocation to generate different construction scenarios.

Path lengths, correlations, and centrality in temporal networks

In temporal networks, where nodes interact via sequences of temporary events, information or resources can only flow through paths that follow the time ordering of events. Such temporal paths play a crucial role in dynamic processes. However, since networks have so far been usually considered static or quasistatic, the properties of temporal paths are not yet well understood. Building on a definition and algorithmic implementation of the average temporal distance between nodes, we study temporal paths in empirical networks of human communication and air transport. Although temporal distances correlate with static graph distances, there is a large spread, and nodes that appear close from the static network view may be connected via slow paths or not at all. Differences between static and temporal properties are further highlighted in studies of the temporal closeness centrality. In addition, correlations and heterogeneities in the underlying event sequences affect temporal path lengths, increasing temporal distances in communication networks and decreasing them in the air transport network.

Energy-efficient mechanisms for managing thread context in throughput processors

Modern graphics processing units (GPUs) use a large number of hardware threads to hide both function unit and memory access latency. Extreme multithreading requires a complicated thread scheduler as well as a large register file, which is expensive to access both in terms of energy and latency. We present two complementary techniques for reducing energy on massively-threaded processors such as GPUs. First, we examine register file caching to replace accesses to the large main register file with accesses to a smaller structure containing the immediate register working set of active threads. Second, we investigate a two-level thread scheduler that maintains a small set of active threads to hide ALU and local memory access latency and a larger set of pending threads to hide main memory latency. Combined with register file caching, a two-level thread scheduler provides a further reduction in energy by limiting the allocation of temporary register cache resources to only the currently active subset of threads. We show that on average, across a variety of real world graphics and compute workloads, a 6-entry per-thread register file cache reduces the number of reads and writes to the main register file by 50% and 59% respectively. We further show that the active thread count can be reduced by a factor of 4 with minimal impact on performance, resulting in a 36% reduction of register file energy.

Abundance and demography of a seasonal aggregation of zebra sharks Stegostoma fasciatum

Seasonal aggregations commonly occur in the marine environment where typically wide-ranging organisms come together to exploit temporary resources or find conspecifics for mating events. The zebra shark Stegostoma fasciatum is a demersal carpet shark that aggregates over the austral summer months in the coastal waters of southeast Queensland, Australia. This study employed photo-identification and mark-recapture methods over a 3 yr period (2003 to 2006) to investigate the population size and structure of this aggregation. In total 327 individual zebra sharks were identified from 570 photographs. Numbered dart-tags on 15 zebra sharks were used to confirm that pigmentation patterns were unique and persistent in wild zebra sharks for up to 810 d. Pollock’s robust design resulted in an annual population estimate of 458 individuals (95% CI = 298–618). The mean number of zebra sharks observed on a single day was 8 (± 8 SE) and the maximum number of zebra sharks seen on a single day was 34. In total, 27% of the sharks were sighted in more than one summer aggregation period and males had greater re-capture probabilities than females. The aggregation consisted exclusively of large (>1800 mm total length) adults with an overall female sex bias of 3.8:1 though sex-ratios varied temporally. Predictable visitation of large, presumably mature individuals to the site raises conservation concerns if aggregations of similar size and structure occur in regions where zebra sharks are fished.

Timers for Distributed Systems

We deal with temporal aspects of distributed systems, introducing and studying a new model called timed distributed π-calculus. This model extends distributed π-calculus with timers, transforming the communication channels into temporary resources. Distributed π-calculus describes located interactions between processes with restricted access to resources. We introduce time constraints by considering timeout timers for channels. Combining these timers with types and locations, we provide a formal framework able to describe complex systems with constraints on time and on resource access. Its typing system and operational semantics are presented. It is proved that the passage of time does not interfere with the typing system. The new model is proved to be sound by using a method based on subject reduction.

Thermal requirements for development and resource partitioning in aphidophagous guilds

The duration of the increase, peak and decline in abundance of the immature stages of sycamore and cereal aphids each year is ephemeral. These temporary resources are exploited by a sequence of aphidophagous insect predators. The temporal sequence in the appearance of the immature stages of coccinellids and syrphids in the sycamore and cereal aphid systems is defined. In spring in the sycamore aphid system and early summer in the cereal aphid system the immature stages of syrphids consistently appeared before those of coccinellids. In the case of the sycamore aphid the autumnal peak in abundance was on average larger than the spring peak, and although attacked by more syrphids, it was not exploited by coccinellids. These temporal patterns in the attack sequence are associated with a difference in the lower developmental thresholds (LDT) of these two groups of predators. The LDT of syrphids (4°C) enables them to be active at lower temperatures and to develop faster between 10° and 27°C than coccinellids, whose LDT is 10°C. As a consequence, early in the year, when temperatures are low but increasing, syrphids appear before and complete their development more quickly than coccinellids, and in the latter half of the year, when temperatures are generally lower and decreasing, only syrphids are likely to be able to complete their development before the aphids disappear. Thus, the niche shift between syrphids and coccinellids is possibly more a consequence of a phylogenetic constraint than a response to competition and or intraguild predation. The relevance of these findings for the ecology of intraguild predation is discussed.

Continental-scale interactions with temporary resources may explain the paradox of large populations of desert waterbirds in Australia

Arid Australia supports extraordinary numbers of waterbirds. We show that the solution to this seeming paradox lies in considering the availability of temporary wetland habitat in the context of the birds dispersal capability and fluctuations in the abundance of wetlands in time and space. For species with large dispersal capabilities, the Lake Eyre Basin of central Australia, amongst the driest regions on the continent, has the highest habitat availability for waterbirds. Analyses of landscape structure show that the wetlands of the Lake Eyre Basin are highly interconnected and linked by broad pathways to wetter parts of south-eastern Australia. These analyses illustrate that organism traits and patch dynamics affect realised habitat availability and indicate that the processes that structure populations may operate at much larger spatial scales than those at which humans usually seek to manage the landscape.

A “marginality” model to explain major spatial and temporal gaps in the old and new world Pleistocene settlement records

AbstractA key argument currently invoked to cast skepticism on certain South American sites, that suggest a first peopling of the New World by ca. 35,000 B.P., is the perplexingly low visibility of the archaeological record until 12,000 B.P. But, contrary to a popular misconception, great spatial and temporal discontinuities are common in the Old World Paleolithic settlement record. In Southern Africa, carefully controlled archaeological stratigraphies show that the now semiarid interior was unoccupied for 50,000 and more years at a time. Episodes of widespread settlement in marginal environments were relatively brief, limited to periods of substantially wetter climate, and closely linked with moist habitats. A risk‐minimization model is proposed to explain these discontinuities. Plant and animal resources in the region, given a climate as dry or drier than today, were of low productivity and low reliability for unspecialized hunter‐gatherers during the dry seasons of poor years. This would require large foraging territories and very wide spacing of proximal bands, so that the exchange of vital information on temporary or migratory resources was minimal. Finally, during extended droughts, fat‐depleted animals provided an unsatisfactory source of food. These variables suggest that environments with low productivity and predictability were too risky for unspecialized hunter‐gatherers with a pre‐Upper Paleolithic technology, such as those who would have been able to enter the New World 35,000 B.P. Major spatial and temporal gaps in the New World settlement record should therefore be expected prior to the appearance of specialized Paleoindian hunter‐gatherers ca. 12,000 B.P. Implications for geoarchaeological strategies are discussed.

Community dynamics of carrion-attendant arthropods in tropical african woodland.

Carcasses are temporary resources which are unbredictable and inconsistent in their availability and locality. A recognisable community of interacting user arthrocods comprising sarcophages, coprophages, dermatophages, keratophages, detritivores, predators and parasites has evolved to exploit the carcass habitat. The large number of arthropods, close confinement, and limited duration of resources necessitates aggressive utilisation. The trophic relations, competition and successionary pattern of these arthropods is discussed. Several pathways to reduce competitive conflict are described. Succession at carcasses is viewed as being inherently different from the traditional concept as the habitat is non-replenishing and does not lead to a climax community.

On access to temporary resources

The shareable resources of a multiprogramming system can be classified as either permanent or temporary, and their use can be classified as either exclusive or non-exclusive. While semaphores, as defined by Dijkstra synchronize access to permanent resources, this article proposes two new primitives for synchronizing access to temporary resources. Their usefulness is demonstrated by examining the problem of a number of concurrent «readers» and »writers« sharing a single file. Finally, a high-level language notation is proposed which synchronizes access to a declared, shareable resource of any of the categories classified above.

The 160-Acre Water Limitation and the Water Resources Commission

HEN Eighty-first Congress passed a bill raising 160-acre water limitation to 480 acres on San Luis Valley, Colorado, project, President Truman vetoed it and asked his temporary Water Resources Policy Commission to examine problem of making exceptions to 160-acre water limitation in particular cases. When commission undertakes this assignment, it may find it neither possible nor desirable to halt its inquiries into limitation at this point. For 160acre limitation, as solicitor of Interior Department has said, is the heart of reclamation law, not a mere appendage to it.1 The limitation embodies nation's high policy on land and water resources, and maintenance of its integrity-not merely question whether, in a particular instance, proper acreage figure is 80, 160, or 480-is at stake. The 160-acre water limitation is device that was enacted by Congress in 1902 to extend historic American land policy to water in arid and semi-arid west. The policy, stemming from Pre-emption Act of 1841 and Homestead Act of 1862, was designed to distribute benefits of public domain widely, by favoring actual settlers against monopolists and speculators of that day. In 1902, when Congress was persuaded that public treasury ought to help develop western irrigation, it limited water rights for private landholding beneficiaries to an amount adequate for no more than 160 acres of each holding. Congress regarded such a limitation necessary to justify spending public funds for private benefit. Without limitation, Congress was unwilling to extend public assistance to reclamation of private lands.2 When lands to be irrigated were publicly owned, these were to be distributed subject to homestead laws in tracts of not less than 40 nor more than 160 acres . . 3 The benefits to private landowners under reclamation law are substantial. The value of waiving interest charges to private irrigation beneficiaries is alone equivalent to more than half cost of a project.4 The Bureau of Reclamation has given Congress additional figures indicating, on Central Valley Project in California, that average Class I water