Type-aware task placement in geo-distributed data centers with low OPEX using data center resizing

With the rising demands on cloud services, the electricity consumption has been increasing drastically as the main operational expenditure (OPEX) to data center providers. The geographical heterogeneity of electricity prices motivates us to study the type-aware task placement problem over geo-distributed data centers. With the consideration of the diversity of user requests and server clusters in modern data centers, we formulate an optimization problem that minimizes OPEX while guaranteeing the quality-of-service, i.e., the expected response time of tasks. Furthermore, an efficient solution is designed for this formulated problem. The experimental results show that our proposal achieves much higher cost-efficiency than the greedy algorithm and much approaches the optimal results. © 2014 IEEE.

Glucose administration and cognitive function: differential effects of age and effort during a dual task paradigm in younger and older adults

RATIONALE: Current research suggests that glucose facilitates performance on cognitive tasks which possess an episodic memory component and a relatively high level of cognitive demand. However, the extent to which this glucose facilitation effect is uniform across the lifespan is uncertain. METHODS: This study was a repeated measures, randomised, placebo-controlled, cross-over trial designed to assess the cognitive effects of glucose in younger and older adults under single and dual task conditions. Participants were 24 healthy younger (average age 20.6 years) and 24 healthy older adults (average age 72.5 years). They completed a recognition memory task after consuming drinks containing 25 g glucose and a placebo drink, both in the presence and absence of a secondary tracking task. RESULTS AND CONCLUSIONS: Glucose enhanced recognition memory response time and tracking precision during the secondary task, in older adults only. These findings do not support preferential targeting of hippocampal function by glucose, rather they suggest that glucose administration differentially increases the availability of attentional resources in older individuals.

Breakdown in central motor control can be attenuated by motor practice and neuro-modulation of the primary motor cortex

The performance of a repetitive index finger flexion–extension task at maximal voluntary rate (MVR) begins to decline just a few seconds into the task and we have previously postulated that this breakdown has a central origin. To test this hypothesis, we have combined two objectives; to determine whether motor practice can lessen the performance deterioration in an MVR task, and whether further gains can be achieved with a transcranial magnetic stimulation (TMS) protocol that increases corticomotor excitability (CME). Eleven right-handed subjects participated in a randomized crossover study design that consisted of a 15-min interventional TMS at I-wave periodicity (ITMS) and single-pulsed Sham intervention prior to six 10-s practice sets of a repetitive finger flexion–extension task at MVR. Motor-evoked potentials (MEPs) were recorded from the first dorsal interosseous muscle. The starting movement rate, and the percentage decline in rate by the end of the MVR were quantitated. Training of the MVR task improved the sustainability of the task by reducing the decline in movement rate. CME increased steadily after each training bout, and this increase was maintained up to 20 min after the last bout. ITMS further increased CME, and was associated with an increase in both the starting rate of the MVR task and its sustainability, when compared to Sham. The results implicate central motor processes in the performance and sustainability of the MVR task, and indicate that MVR kinematics can improve with short-term training and with non-invasive neuro-modulation.

Changes in corticomotor excitability and inhibition after exercise are influenced by hand dominance and motor demand

Previous studies on handedness have often reported functional asymmetries in corticomotor excitability (CME) associated with voluntary movement. Recently, we have shown that the degree of post-exercise corticomotor depression (PED) and increase in short-interval cortical inhibition (SICI) after a repetitive finger movement task was less when the task was performed at a maximal voluntary rate (MVR) than when it was performed at a submaximal sustainable rate (SR). In the current study, we have compared the time course of PED and SICI in the dominant (DOM) and nondominant (NDOM) hands after an MVR and SR finger movement task to determine the influence of hand dominance and task demand. We tracked motor-evoked potential (MEP) amplitude from the first dorsal interosseous muscle of the DOM and NDOM hand for 20 min after a 10-s index finger flexion-extension task at MVR and SR. For all hand-task combinations, we report a period of PED and increased SICI lasting for up to 8 min. We find that the least demanding task, one that involved index finger movement of the DOM hand at SR, was associated with the greatest change in PED and SICI from baseline (63.6±5.7% and 79±2%, P<0.001, PED and SICI, respectively), whereas the most demanding task (MVR of the NDOM hand) was associated with the least change from baseline (PED: 88.1±3.6%, SICI: 103±2%; P<0.001). Our findings indicate that the changes in CME and inhibition associated with repetitive finger movement are influenced both by handedness and the degree of demand of the motor task and are inversely related to task demand, being smallest for an MVR task of the NDOM hand and greatest for an SR task of the DOM hand. The findings provide additional evidence for differences in neuronal processing between the dominant and nondominant hemispheres in motor control.

Post-exercise depression in corticomotor excitability after dynamic movement: a general property of fatiguing and non-fatiguing exercise

Transcranial magnetic stimulation has been used to study changes in central excitability associated with motor tasks. Recently, we reported that a finger flexion–extension task performed at a maximal voluntary rate (MVR) could not be sustained and that this was not due to muscle fatigue, but was more likely a breakdown in central motor control. To determine the central changes that accompany this type of movement task, we tracked motor-evoked potential (MEP) amplitude from the first dorsal interosseous (FDI) and abductor pollicis brevis (APB) muscles of the dominant hand in normal subjects for 20 min after a 10 sec index finger flexion–extension task performed at MVR and at a moderate sustainable rate (MSR) and half the MSR (MSR/2). The FDI MEP amplitude was reduced for up to 6–8 min after each of the tasks but there was a greater and longer-lasting reduction after the MSR and MSR/2 tasks compared to the MVR task. There was a similar reduction in the amplitude of the FDI MEP after a 10 sec cyclic index finger abduction–adduction task when the FDI was acting as the prime mover. The amplitude of the MEP recorded from the inactive APB was also reduced after the flexion–extension tasks, but to a lesser degree and for a shorter duration. Measurements of short-interval cortical inhibition revealed an increase in inhibition after all of the finger flexion–extension tasks, with the MSR task being associated with the greatest degree of inhibition. These findings indicate that a demanding MVR finger movement task is followed by a period of reduced corticomotor excitability and increased intracortical inhibition. However, these changes also occur with and are greater with slower rates of movement and are not specific for motor demand, but may be indicative of adaptive changes in the central motor pathway after a period of repetitive movement.

Promoting reasoning through the magic V task

Reasoning in mathematics plays a critical role in developing mathematical understandings. In this article, Bragg, Loong, Widjaja, Vale and Herbert explore an adaptation of the Magic V Task and how was used in several classrooms to promote and develop reasoning skills.

Effectiveness of dual-task functional power training for preventing falls in older people: study protocol for a cluster randomised controlled trial

BACKGROUND: Falls are a major public health concern with at least one third of people aged 65 years and over falling at least once per year, and half of these will fall repeatedly, which can lead to injury, pain, loss of function and independence, reduced quality of life and even death. Although the causes of falls are varied and complex, the age-related loss in muscle power has emerged as a useful predictor of disability and falls in older people. In this population, the requirements to produce explosive and rapid movements often occurs whilst simultaneously performing other attention-demanding cognitive or motor tasks, such as walking while talking or carrying an object. The primary aim of this study is to determine whether dual-task functional power training (DT-FPT) can reduce the rate of falls in community-dwelling older people. METHODS/DESIGN: The study design is an 18-month cluster randomised controlled trial in which 280 adults aged ≥65 years residing in retirement villages, who are at increased risk of falling, will be randomly allocated to: 1) an exercise programme involving DT-FPT, or 2) a usual care control group. The intervention is divided into 3 distinct phases: 6 months of supervised DT-FPT, a 6-month 'step down' maintenance programme, and a 6-month follow-up. The primary outcome will be the number of falls after 6, 12 and 18 months. Secondary outcomes will include: lower extremity muscle power and strength, grip strength, functional assessments of gait, reaction time and dynamic balance under single- and dual-task conditions, activities of daily living, quality of life, cognitive function and falls-related self-efficacy. We will also evaluate the cost-effectiveness of the programme for preventing falls. DISCUSSION: The study offers a novel approach that may guide the development and implementation of future community-based falls prevention programmes that specifically focus on optimising muscle power and dual-task performance to reduce falls risk under 'real life' conditions in older adults. In addition, the 'step down' programme will provide new information about the efficacy of a less intensive maintenance programme for reducing the risk of falls over an extended period. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN12613001161718 . Date registered 23 October 2013.

Culture and corporate voluntary reporting: a comparative exploration of the chairperson's report in India and New Zealand

Purpose – The purpose of this paper is to explore the cultural underpinnings of accounting practices through a comparative analysis of India and New Zealand, using the chairperson's report, which is increasingly becoming one of the most important segments of the corporate annual report.
Design/methodology/approach – The annual reports of Indian and New Zealand companies from 2001 to 2005 were selected to investigate the extent and nature of information disclosure in their chairperson's report. “Content analysis” is the main methodological orientation of the paper.
Findings – The paper argues that, contrary to propositions based on Hofstede's cultural framework, Indian companies provide more disclosure in their chairperson's report than their New Zealand counterparts. This leads to the conclusion that voluntary disclosure, more generally, is a complex phenomenon and cultural variables alone may not be sufficient predictors of the voluntary disclosure practices of a country.
Originality/value – Using India and New Zealand, two countries with significant cultural differences, according to Hofstede's typology, the paper extends the literature by focusing on the chairperson's report, a more recent accounting phenomenon which is gaining popularity across the globe.

A shadow-like task migration model based on context semantics for mobile and pervasive environments

Pervasive computing is a user-centric mobile computing paradigm, in which tasks should be migrated over different platforms in a shadow-like way when users move around. In this paper, we propose a context-sensitive task migration model that recovers program states and rebinds resources for task migrations based on context semantics through inserting resource description and state description sections in source programs. Based on our model, we design and develop a task migration framework xMozart which extends the Mozart platform in terms of context awareness. Our approach can recover task states and rebind resources in the context-aware way, as well as support multi- modality I/O interactions. The extensive experiments demonstrate that our approach can migrate tasks by resuming them from the last broken points like shadows moving along with the users.

Fighting fires and fatigue: sleep, physical activity, and physical task performance

 During bushfires, firefighters often work long shifts with little sleep. Grace’s research showed that although firefighters’ sleep is restricted, it does not adversely affect their ability to perform physical tasks. This contrasts the cognitive impairments associated with sleep loss and could prompt revision of fatigue management guidelines in physically-demanding occupations.

Studying mathematics teacher education: analysing the process of task variation on learning

Self-study of variations to task design offers a way of analysing how learning takes place. Over several years, variations were made to improve an assessment task completed by final-year teacher candidates in a primary mathematics teacher education subject. This article describes how alterations to a task informed on-going developments in self-study of one assessment task employed in an online subject. Analysis of my journal, notes from conversations with colleagues, teacher candidates’ work on the task and responses to online forums, and survey data inspired variations focused on better exploration of key concepts involved in the task, raising of focal awareness, developing a stronger professional eye in the students and the author, adaptations for multiple curriculum levels, and explorations of dual teacher–student perspectives. The overall challenge has been to support teacher candidates to learn to design effective open-ended tasks with a critical professional eye. Descriptions of the changes made to the task and the development of my own professional eye as a consequence of the application of self-study are included. Data show that variations to the task increased teacher candidates’ understanding of mathematics problem posing and generated pedagogical insights for task design.

The impact of mandatory versus voluntary auditor switches on stock liquidity: some Korean evidence

Using Korean listed firms subject to the auditor "designation rule", this paper shows that (1) firms that switch auditors exhibit lower stock liquidity than firms that do not switch auditors, and (2) the negative liquidity effect of auditor switches is concentrated in firms that switch to low-quality auditors. Meanwhile, firms that switch auditors under the auditor designation system do not exhibit lower stock liquidity, consistent with audit designation mitigating the concerns about audit quality deterioration around auditor changes. Furthermore, we find that foreign ownership has a mitigating impact on the negative relation between auditor switches and stock liquidity, suggesting that investors are less concerned about auditor switches when an alternative monitoring mechanism exists.

Oxytocin enhances the appropriate use of human social cues by the domestic dog (Canis familiaris) in an object choice task

It has been postulated that the neuropeptide, oxytocin, is involved in human-dog bonding. This may explain why dogs, compared to wolves, are such good performers on object choice tasks, which test their ability to attend to, and use, human social cues in order to find hidden food treats. The objective of this study was to investigate the effect of intranasal oxytocin administration, which is known to increase social cognition in humans, on domestic dogs' ability to perform such a task. We hypothesised that dogs would perform better on the task after an intranasal treatment of oxytocin. Sixty-two (31 males and 31 females) pet dogs completed the experiment over two different testing sessions, 5-15 days apart. Intranasal oxytocin or a saline control was administered 45 min before each session. All dogs received both treatments in a pseudo-randomised, counterbalanced order. Data were collected as scores out of ten for each of the four blocks of trials in each session. Two blocks of trials were conducted using a momentary distal pointing cue and two using a gazing cue, given by the experimenter. Oxytocin enhanced performance using momentary distal pointing cues, and this enhanced level of performance was maintained over 5-15 days time in the absence of oxytocin. Oxytocin also decreased aversion to gazing cues, in that performance was below chance levels after saline administration but at chance levels after oxytocin administration.

Cultural intelligence (CQ) in virtual, cross-cultural interactions: generalizability of measure and links to personality dimensions and task performance

Previous studies have focused on investigating CQ in face-to-face contexts but very few have assessed CQ in virtual, cross-cultural interactions. This study highlights the relevance of cultural intelligence (CQ) as an intercultural capability in cross-cultural communications that are virtual. This two-study research (study 1: n = 274; study 2: n = 223) conducted in call centers in the Philippines (a) assesses the generalizability of the four-factor CQ model (i.e., cognitive, metacognitive, motivational and behavioral CQ) as applied in the virtual context and (b) tests the relationship between CQ, personality dimensions (i.e., openness to experience and extraversion) and supervisor’s ratings of task performance. Study 1 results show that the structural validity of the four-factor CQ model was supported with minor issues in some ofthe items indicating the need to modify the CQ measure when utilized in the virtual context. Study 2 results show that CQ is positively and significantly related to openness to experience and extraversion. In addition, results show that CQ predicts task performance highlighting the importance of developing CQ among call center representatives and other working professionals who virtually engage and interact with clients and customers from culturally diverse backgrounds.