Numerical exploration of plastic deformation mechanisms of copper nanowires with surface defects

Based on the molecular dynamics simulation, plastic deformation mechanisms associated with the zigzag stress curves in perfect and surface defected copper nanowires under uniaxial tension are studied. In our previous study, it has found that the surface defect exerts larger influence than the centro-plane defect, and the 45o surface defect appears as the most influential surface defect. Hence, in this paper, the nanowire with a 45o surface defect is chosen to investigate the defect’s effect to the plastic deformation mechanism of nanowires. We find that during the plastic deformation of both perfect and defected nanowires, decrease regions of the stress curve are accompanied with stacking faults generation and migration activities, but during stress increase, the structure of the nanowire appears almost unchanged. We also observe that surface defects have obvious influence on the nanowire’s plastic deformation mechanisms. In particular, only two sets of slip planes are found to be active and twins are also observed in the defected nanowire.

A review of locative media, mobile and embodied spatial interaction

Highlights ► Provides a review of the history and development of locative media. ► Outlines different human-computer interaction techniques applied in locative media. ► Discusses how locative media applications have changed interaction affordances in and of physical spaces. ► Discusses practices of people in urban settings that evolved through these new affordances. ► Provides an overview on methods to investigate and elaborate design principles for future locative media.

Functional fixation : experimental evidence on the presentation of financial information through different digital formats

This study examines whether, in the presentation of financial information, digital formats address the concern over users’ functional fixation. The accounting literature indicates that the presentation of financial information either within the financial statements or in the notes to the financial statements often creates functional fixation where users of financial statements fail to adjust for differences in accounting policy. This leads users to judge what would otherwise be identical financial situations as being different due to the different accounting policies and methods adopted. It has been suggested that the use of digital formats in presenting financial reports may overcome functional fixation. Using an experimental design involving accountants in public practice, the results indicate that the use of digital formats to present financial reports does not fully overcome the issue of functional fixation in the processing of financial information. Although the participants were able to identify and extract relevant information, irrespective of whether or not the information was presented within the financial statements or in the notes to the accounts, the evidence indicates that functional fixation remained when the participants made final decisions based on available information. This suggests that functional fixation may not be caused by access to or extraction of information but by the level of perceived significance based on where the information is reported in the financial statements. In general, the results indicate that current technology may not be able to fully reduce functional fixation in the evaluation of financial information prepared in accordance with different accounting policies and methods.

The effect of ocular surface conditions on blink rate and completeness

A healthy human would be expected to show periodic blinks, making a brief closure of the eyelids. Most blinks are spontaneous, occurring regularly with no external stimulus. However a reflex blink can occur in response to external stimuli such as a bright light, a sudden loud noise, or an object approaching toward the eyes. A voluntary or forced blink is another type of blink in which the person deliberately closes the eyes and the lower eyelid raises to meet the upper eyelid. A complete blink, in which the upper eyelid touches the lower eyelid, contributes to the health of ocular surface by providing a fresh layer of tears as well as maintaining optical integrity by providing a smooth tear film over the cornea. The rate of blinking and its completeness vary depending on the task undertaken during blink assessment, the direction of gaze, the emotional state of the subjects and the method under which the blink was measured. It is also well known that wearing contact lenses (both rigid and soft lenses) can induce significant changes in blink rate and completeness. It is been established that efficient blinking plays an important role in ocular surface health during contact lens wear and for improving contact lens performance and comfort. Inefficient blinking during contact lens wear may be related to a low blink rate or incomplete blinking and can often be a reason for dry eye symptoms or ocular surface staining. It has previously been shown that upward gaze can affect blink rate, causing it to become faster. In the first experiment, it was decided to expand on previous studies in this area by examining the effect of various gaze directions (i.e. upward gaze, primary gaze, downward gaze and lateral gaze) as well as head angle (recumbent position) on normal subjects’ blink rate and completeness through the use of filming with a high-speed camera. The results of this experiment showed that as the open palpebral aperture (and exposed ocular surface area) increased from downward gaze to upward gaze, the number of blinks significantly increased (p<0.04). Also, the size of closed palpebral aperture significantly increased from downward gaze to upward gaze (p<0.005). A weak positive correlation (R² = 0.18) between the blink rate and ocular surface area was found in this study. Also, it was found that the subjects showed 81% complete blinks, 19% incomplete blinks and 2% of twitch blinks in primary gaze, consistent with previous studies. The difference in the percentage of incomplete blinks between upward gaze and downward gaze was significant (p<0.004), showing more incomplete blinks in upward gaze. The findings of this experiment suggest that while blink rate becomes slower in downward gaze, the completeness of blinking is typically better, thereby potentially reducing the risk of tear instability. On the other hand, in upward gaze while the completeness of blinking becomes worse, this is potentially offset by increased blink frequency. In addition, blink rate and completeness were not affected by lateral gaze or head angle, possibly because these conditions have similar size of the open palpebral aperture compared with primary gaze. In the second experiment, an investigation into the changes in blink rate and completeness was carried out in primary gaze and downward gaze with soft and rigid contact lenses in unadapted wearers. Not surprisingly, rigid lens wear caused a significant increase in the blink rate in both primary (p<0.001) and downward gaze (p<0.02). After fitting rigid contact lenses, the closed palpebral aperture (blink completeness) did not show any changes but the open palpebral aperture showed a significant narrowing (p<0.04). This might occur from the subjects’ attempt to avoid interaction between the upper eyelid and the edge of the lens to minimize discomfort. After applying topical anaesthetic eye drops in the eye fitted with rigid lenses, the increased blink rate dropped to values similar to that before lens insertion and the open palpebral aperture returned to baseline values, suggesting that corneal and/or lid margin sensitivity was mediating the increased blink rate and narrowed palpebral aperture. We also investigated the changes in the blink rate and completeness with soft contact lenses including a soft sphere, double slab-off toric design and periballast toric design. Soft contact lenses did not cause any significant changes in the blink rate, closed palpebral aperture, open palpebral aperture and the percentage of incomplete blinks in either primary gaze or downward gaze. After applying anaesthetic eye drops, the blink rate reduced in both primary gaze and downward gaze, however this difference was not statistically significant. The size of the closed palpebral aperture and open palpebral aperture did not show any significant changes after applying anaesthetic eye drops. However it should be noted that the effects of rigid and soft contact lenses that we observed in these studies were only the immediate reaction to contact lenses and in the longer term, it is likely that these responses will vary as the eye adapts to the presence of the lenses.

A review of the acculturation experiences of international students

Universities in Western countries host a substantial number of international students. These students bring a range of benefits to the host country and in return the students gain higher education. However, the choice to study overseas in Western countries may present many challenges for the international student including the experience of acculturative stress and difficulties with adjustment to the environment of the host country. The present paper provides a review of current acculturation models as applied to international students. Given that these models have typically been empirically tested on migrant and refugee populations only, the review aims to determine the extent to which these models characterise the acculturation experience of international students. Literature pertaining to salient variables from acculturation models was explored including acculturative stressors encountered frequently by international students (e.g., language barriers, educational difficulties, loneliness, discrimination, and practical problems associated with changing environments). Further discussed was the subsequent impact of social support and coping strategies on acculturative stress experienced by international students, and the psychological and sociocultural adaptation of this student group. This review found that the international student literature provides support for some aspects of the acculturation models discussed, however, further investigation of these models is needed to determine their accuracy in describing the acculturation of international students. Additionally, prominent acculturation models portray the host society as an important factor influencing international students’ acculturation, which suggests the need for future intervention.

Psychological interventions for alcohol misuse among people with co-occurring depression or anxiety disorders: A systematic review

Abstract OBJECTIVE: Depression, anxiety and alcohol misuse frequently co-occur. While there is an extensive literature reporting on the efficacy of psychological treatments that target depression, anxiety or alcohol misuse separately, less research has examined treatments that address these disorders when they co-occur. We conducted a systematic review to determine whether psychological interventions that target alcohol misuse among people with co-occurring depressive or anxiety disorders are effective. DATA SOURCES: We systematically searched the PubMed and PsychINFO databases from inception to March 2010. Individual searches in alcohol, depression and anxiety were conducted, and were limited to 'human' published 'randomized controlled trials' or 'sequential allocation' articles written in English. STUDY SELECTION: We identified randomized controlled trials that compared manual guided psychological interventions for alcohol misuse among individuals with depressive or anxiety disorders. Of 1540 articles identified, eight met inclusion criteria for the review. DATA EXTRACTION: From each study, we recorded alcohol and mental health outcomes, and other relevant clinical factors including age, gender ratio, follow-up length and drop-out rates. Quality of studies was also assessed. DATA SYNTHESIS: Motivational interviewing and cognitive-behavioral interventions were associated with significant reductions in alcohol consumption and depressive and/or anxiety symptoms. Although brief interventions were associated with significant improvements in both mental health and alcohol use variables, longer interventions produced even better outcomes. CONCLUSIONS: There is accumulating evidence for the effectiveness of motivational interviewing and cognitive behavior therapy for people with co-occurring alcohol and depressive or anxiety disorders.