Sedentary behavior and depression among adults : a review

Background Physically inactive lifestyles and sedentary behaviors (SB) are key contributors to ill health. Although the association between SB (e.g., watching TV/using the computer) and physical health has been well documented, increasing research has focused on the possible link between SB and mental health (e.g., depression).

Purpose This review aims to investigate the effect of SB on the risk of depression in adults.

Method A systematic search for original research articles investigating associations between SB and depression in adults was performed using the several electronic data bases.

Results A total of seven observational and four intervention studies were included in this review. All observational studies found positive associations between SB and risk of depression, while intervention studies showed contradictory results.

Conclusion Evidence for the relationship between SB and risk of depression in adults is limited by methodological weaknesses. However, on balance, this review suggests that SB is associated with an increased risk of depression. Further studies are needed assessing different types of SB and depression; the interrelationship between physical activity, SB, and depression; causal links between SB and depression; and intervention strategies aimed at reducing SB and their effects on risk of depression.

Novel strategies to promote children's physical activities and reduce sedentary behavior

Physical activity and sedentary behavior (performed primarily while sitting) play a key role in the current and future health of young people. Most health evidence and intervention strategies targeting reductions in children’s sedentary behavior have focused on television viewing, with mixed evidence as to the effectiveness of these strategies and of the importance of television viewing for children’s health. Evidence from studies with adults using objective measures of sedentary behavior suggests that accumulated sedentary time is independently associated with metabolic health; importantly, emerging evidence suggests that the manner in which the sedentary behavior is accrued (ie, frequency of interruptions to time spent sedentary) may also have independent effects on health. Potential novel intervention approaches to reduce children’s sedentary time include activity breaks during class time at school, delivery of active lessons and homework, and changes to the classroom environment. Further evidence of the importance of sedentary time (both total accumulation and frequency of interruptions) on children’s health is required. Future studies should assess the effectiveness of interventions targeting organizational and pedagogical changes in schools as well as using homework to engage with families in more active ways.

The effect of skin passing on the material behavior of metal strip in pure bending and tension

The metal strip used in roll forming has often been preprocessed by (tension or roller) leveling or by skin-pass rolling, and as a consequence, may contain residual stresses. These stresses are not well observed by the tensile test, but could have a significant effect on the bending and springback behavior. With the advent of improved process design techniques for roll forming, including advanced finite element techniques, the need for precise material property data has become important. The major deformation mode of roll forming is that of bending combined with unloading and reverse bending, and hence property data derived from bend tests could be more relevant than that from tensile testing.

This work presents a numerical study on the effect of skin passing on the material behavior of stainless steel strip in pure bending and tension. A two dimensional (2-D) numerical model was developed using Abaqus Explicit to analyze the affect of skin passing on the residual stress profile across a section for various working conditions. The deformed meshes and their final stress fields were then imported as pre-defined fields into Abaqus Standard, and the post-skin passing material behavior in pure bending was determined. The results show that a residual stress profile is introduced into the steel strip during skin passing, and that its shape and stress level depend on the overall thickness reduction as well as the number of rolling passes used in the skin passing process. The material behavior in bending and the amount of springback changed significantly depending on the skin pass condition.

Machine learning approaches for modeling spammer behavior

Spam is commonly known as unsolicited or unwanted email messages in the Internet causing potential threat to Internet Security. Users spend a valuable amount of time deleting spam emails. More importantly, ever increasing spam emails occupy server storage space and consume network bandwidth. Keyword-based spam email filtering strategies will eventually be less successful to model spammer behavior as the spammer constantly changes their tricks to circumvent these filters. The evasive tactics that the spammer uses are patterns and these patterns can be modeled to combat spam. This paper investigates the possibilities of modeling spammer behavioral patterns by well-known classification algorithms such as Naïve Bayesian classifier (Naive Bayes), Decision Tree Induction (DTI) and Support Vector Machines (SVMs). Preliminary experimental results demonstrate a promising detection rate of around 92%, which is considerably an enhancement of performance compared to similar spammer behavior modeling research.

Western consumers' understanding of carbon offsets and its relationship to behavior

Purpose – The purpose of this paper is to examine Western consumers’ levels of general environmental knowledge and specific knowledge related to carbon offsets and the relationships between specific types of environmental knowledge and consumers’ related behaviors.

Design/methodology/approach – The study surveyed consumers from Australia (n ¼ 345) and the USA (n ¼ 340) who were sourced through national online panels. The analysis looks at differences between knowledge and behaviors, both across the samples as well as whether there are differences between consumers with high and low levels of environmental and carbon offset knowledge, and whether demographics impact on knowledge levels.

Findings – The results found that consumers had higher levels of general knowledge than carbon offset knowledge and the two types of knowledge were not related. ANOVA results considering country differences and demographic factors found that general knowledge was affected by education, age and gender, with carbon knowledge being affected by education. Environmental behavior was affected by age and gender as well, and no demographic factors influenced carbon-related behavior. Respondent’s location (i.e. USA or Australia) did not influence knowledge or behaviors, but interacted with education in regard to carbon knowledge and behavior.

Social implications – This research suggests that consumers are not acting on their carbon knowledge, which may be due to the debate surrounding carbon issues and/or because the information is based on complex scientific foundations, which the average consumer may have difficulty grasping, regardless of country.

Originality/value – This is one of the first pieces of academic research to explore consumers’ understanding of carbon-related information and how this knowledge impacts behavior. It also proposes a measure for evaluating carbon offset knowledge, which could be used to broaden environmental knowledge assessments.

Detecting unknown anomalous program behavior using API system calls

This paper presents the detection techniques of anomalous programs based on the analysis of their system call traces. We collect the API calls for the tested executable programs from Microsoft detour system and extract the features for our classification task using the previously established n-gram technique. We propose three different feature extraction approaches in this paper. These are frequency-based, time-based and a hybrid approach which actually combines the first two approaches. We use the well-known classifier algorithms in our experiments using WEKA interface to classify the malicious programs from the benign programs. Our empirical evidence demonstrates that the proposed feature extraction approaches can detect malicious programs over 88% which is quite promising for the contemporary similar research.

A cluster-randomized controlled trial to reduce sedentary behavior and promote physical activity and health of 8-9 year olds : the transform-us! study

Background: Physical activity (PA) is associated with positive cardio-metabolic health and emerging evidence suggests sedentary behavior (SB) may be detrimental to children’s health independent of PA. The primary aim of the Transform-Us! study is to determine whether an 18-month, behavioral and environmental intervention in the school and family settings results in higher levels of PA and lower rates of SB among 8-9 year old children compared with usual practice (post-intervention and 12-months follow-up). The secondary aims are to determine the independent and combined effects of PA and SB on children’s cardio-metabolic health risk factors; identify the factors that mediate the success of the intervention; and determine whether the intervention is cost-effective.
Methods/design: A four-arm cluster-randomized controlled trial (RCT) with a 2 × 2 factorial design, with schools as the unit of randomization. Twenty schools will be allocated to one of four intervention groups, sedentary behavior (SB-I), physical activity (PA-I), combined SB and PA (SB+PA-I) or current practice control (C), which will be evaluated among approximately 600 children aged 8-9 years in school year 3 living in Melbourne, Australia. All children in year 3 at intervention schools in 2010 (8-9 years) will receive the intervention over an 18-month period with a maintenance ‘booster’ delivered in 2012 and children at all schools will be invited to participate in the evaluation assessments. To maximize the sample and to capture new students arriving at intervention and control schools, recruitment will be on-going up to the post-intervention time point. Primary outcomes are time spent sitting and in PA assessed via accelerometers and inclinometers and survey.
Discussion: To our knowledge, Transform-Us! is the first RCT to examine the effectiveness of intervention strategies for reducing children’s overall sedentary time, promoting PA and optimizing health outcomes. The integration of consistent strategies and messages to children from teachers and parents in both school and family settings is a critical component of this study, and if shown to be effective, may have a significant impact on educational policies as well as on pedagogical and parenting practices.

Depression and sickness behavior are Janus-faced responses to shared inflammatory pathways

It is of considerable translational importance whether depression is a form or a consequence of sickness behavior. Sickness behavior is a behavioral complex induced by infections and immune trauma and mediated by pro-inflammatory cytokines. It is an adaptive response that enhances recovery by conserving energy to combat acute inflammation. There are considerable phenomenological similarities between sickness behavior and depression, for example, behavioral inhibition, anorexia and weight loss, and melancholic (anhedonia), physio-somatic (fatigue, hyperalgesia, malaise), anxiety and neurocognitive symptoms. In clinical depression, however, a transition occurs to sensitization of immuno-inflammatory pathways, progressive damage by oxidative and nitrosative stress to lipids, proteins, and DNA, and autoimmune responses directed against self-epitopes. The latter mechanisms are the substrate of a neuroprogressive process, whereby multiple depressive episodes cause neural tissue damage and consequent functional and cognitive sequelae. Thus, shared immuno-inflammatory pathways underpin the physiology of sickness behavior and the pathophysiology of clinical depression explaining their partially overlapping phenomenology. Inflammation may provoke a Janus-faced response with a good, acute side, generating protective inflammation through sickness behavior and a bad, chronic side, for example, clinical depression, a lifelong disorder with positive feedback loops between (neuro)inflammation and (neuro)degenerative processes following less well defined triggers.

Effects of crystallographic orientation on corrosion behavior of magnesium single crystals

The corrosion behavior of magnesium single crystals with various crystallographic orientations was examined in this study. To identify the effects of surface orientation on the corrosion behavior in a systematic manner, single-crystal specimens with ten different rotation angles of the plane normal from the [0001] direction to the [1010] direction at intervals of 10° were prepared and subjected to potentiodynamic polarization and potentiostatic tests as well as electrochemical impedance spectroscopy (EIS) measurements in 3.5 wt.% NaCl solution. Potentiodynamic polarization results showed that the pitting potential (E _pit) first decreased from −1.57 V _SCE to −1.64 V _SCE with an increase in the rotation angle from 0° to 40°, and then increased to −1.60 V _SCE with a further increase in the rotation angle to 90°. The results obtained from potentiostatic tests are also in agreement with the trend in potentiodynamic polarization tests as a function of rotation angle. A similar trend was also observed for the depressed semicircle and the total resistances in the EIS measurements due to the facile formation of MgO and Mg(OH)₂ passive films on the magnesium surface. In addition, the amount of chloride in the passive film was found first to increase with an increase in rotation angle from 0° to 40°, then decrease with a further increase in rotation angle, indicating that the tendency to form a more protective passive film increased for rotation angle near 0° [the (0001) plane] or 90° [the (1010) plane].

Pathways from school suspension to adolescent nonviolent antisocial behavior in students in Victoria, Australia and Washington State, United States

School suspension is associated with school dropout, crime, delinquency, and alcohol and other drug use for the suspended student. Important research questions are how academic and related factors are relevant to the school suspension process and the generality of the process in different sites. State-representative samples of Grade 7 students (N = 1,945) in Washington State, United States and Victoria, Australia were followed from 2002 to 2004. In both states, Grade 7 school suspension was associated with higher rates of nonviolent antisocial behavior and suspension 24 months later, before Grade 8 factors were entered into the model. Relevant factors were Grade 8 low school grades and association with antisocial peers, as well as Grade 8 antisocial behavior in Washington State only. The implications of these findings for the ways in which suspension is used in schools are outlined.

Correlates of aggressive behavior in dementia

Background and Objective: A review of current literature was undertaken in order to summarize some of the possible biopsychosocial contributions to the development of aggressive behavior in elderly people with dementia. It was intended that such a summary would provide a useful clinical aid when assessing patients with behavioral symptoms and a starting point for undertaking research in this area. Method: Information was gathered from literature searches conducted on several occasions between 1995 and 2001 using 3 databases (Medline, CINHAL and PsycINFO), as well as journals and books available from the libraries of the authors and from Monash University, Melbourne, Australia. Results: Associations between various conditions and the development of aggressive behavior were found, including the contributions of degrees of cognitive impairment, personality, sensory change, physical illness, language impairment, brain pathology, affective and psychotic disorders. The role of gender, sexuality and disruption of circadian rhythms is also discussed, as is the importance of environmental factors. Conclusion: Identification of correlates of aggressive behavior may assist clinicians to understand and manage aggressive behavior more effectively.

Behavior and weight correlates of weight-control efforts in Australian women living in disadvantage : the READI study

Background
With increasing obesity rates worldwide, more and more people are actively attempting to lose weight or avoid weight gain, but relatively little is known about what specific behaviors comprise these efforts and which, if any, are associated with better weight control over time.

Methods
This paper reports relationships between body weight, weight-control efforts and related behaviors over a three-year period in 1,634 Australian women. The women were purposefully recruited from 80 disadvantaged neighborhoods in Victoria, Australia. Weight loss efforts were categorized as trying to lose weight, trying to prevent weight gain and no weight-control efforts. Behavioral correlates examined included different kinds of physical activity and consumption of a number of specific foods types.

Results and discussion
Self-reported body weight at baseline was higher in women trying to lose weight. Frequency of consumption of low energy density foods was positively associated with reported weight-control efforts, as was frequency of reported total and leisure-time physical activity. Longitudinal associations between changes in weight-control efforts and changes in behaviors were consistent with the cross-sectional findings. At three-year follow up, however, weight-control efforts were not associated with change in body weight. More detailed analyses of specific food choices suggested that part of the explanation of no effect of reported weight-control efforts and weight over time might be that people are not as well-informed as they should be about the energy density of some common foods. In particular, those reporting engagement in weight-control efforts reported reducing consumption of carbohydrate-containing foods such as bread and potatoes more than is justified by their energy content, while they reported increasing consumption of some high energy density foods (e.g., cheese and nuts).

Conclusion
It is tentatively concluded that women living in disadvantaged neighborhoods understand messages about weight-control (more activity and foods with lower fat and lower energy density) but that some foods eaten more by women engaged in weight control may reduce the effectiveness of these efforts.

Approach for testing the material behavior in roll forming in a small scale

Roll forming of ultra-high strength steels (UHSS) and other high strength alloys is an advanced manufacturing methodology with the ability of cold forming those materials to complex three-dimensional shapes for lightweight structural applications. Due to their high strength, most of these materials have a reduced ductility which excludes conventional sheet forming methods under cold forming conditions. Roll forming is possible due to its low strains and incremental forming characteristic. Recent research investigates the development of high strength nano-structured aluminum sheet and titanium alloys, as well as their behaviour in roll forming with regard to formability, material behaviour and shape defects. The development of new materials is often limited to small scale samples due to the high preparation costs. In contrast, industrial application needs larger scale tests for validation, especially in roll forming where a minimum sheet length is required to feed the sample trough the roll forming machine. This work describes a novel technique for studying roll forming of a short length of experimental material. DP780 steel strips (500mm – 1300mm length) were welded between two mild steel carrier sheets of similar width and thickness giving an overall strip length of 2m. Roll forming trials were performed and longitudinal edge strain, bow and springback determined on the welded samples and samples formed of full length DP780 strip before and after cut off. The experimental results of this work show that this method gives a reasonable approach for predicting material behavior in roll forming transverse to the rolling direction. In contrast to that significant differences in longitudinal bow were observed between the welded sections and the sections formed of full length DP780 strip; this indicates that the applicability of this method is limited with regard to predicting longitudinal material behavior in roll forming.

Physical activity, sedentary behavior, and postnatal depressive symptoms: a review

Context:
Postnatal depression is highly prevalent in mothers. Although physical activity has been found to reduce the risk of depression in the general population, little is known regarding its link with postnatal depression. This review examined original research investigating the relationship between physical activity and sedentary behavior dose (frequency, intensity, and duration) and domain, and postnatal depressive symptoms. 

Evidence acquisition:
A systematic search for original research investigating the relationship between physical activity and sedentary behavior dose and domain, and postnatal depressive symptoms, was performed using several electronic databases in early 2012. A total of ten observational and seven intervention studies were included. 

Evidence synthesis:
Most studies (one cross-sectional, two longitudinal, and six intervention studies) found an inverse association between postpartum leisure-time physical activity (LTPA) and postnatal depressive symptoms. One longitudinal study found that occupational physical activity was positively associated with postnatal depressive symptoms. There was inconclusive evidence to suggest an optimal dose of postpartum physical activity for reducing postnatal depressive symptoms. Two longitudinal studies found an inverse association between antenatal LTPA and presence of postnatal depressive symptoms. One of two studies that investigated sedentary behavior found a positive cross-sectional association between sedentary behavior and presence of postnatal depressive symptoms.

Conclusions:
Although studies are limited, on balance, LTPA prior to, during, and after pregnancy may be important for reducing the risk of postnatal depression. Further research is required to determine the optimal dose and domain of physical activity for reducing postnatal depressive symptoms as well as to examine the link between  sedentary behavior and postnatal depressive symptoms.

Phase behavior and nanomechanical mapping of block ionomer complexes

Block ionomer complexes SSEBS-c-PCL were prepared, as a consequence of proton transfer from the sulfonic acid of sulfonated polystyrene-block- poly(ethylene-ran-butylene)-block-polystyrene (SSEBS) to the tertiary amine of a tertiary amine terminated poly(?-caprolactone) (APCL). The phase behavior of SSEBS-c-PCL was thoroughly investigated and the results showed that APCL in SSEBS-c-PCL displays unique crystallization behavior owing to the influence of interactions between the amine and sulfonic acid groups as well as the effects of confinement. Further, small-angle X-ray scattering study revealed that SSEBS-c-PCL displays a less ordered micro-phase structure compared to SSEBS. A quantitative mapping of mechanical properties at the nanoscale was achieved using peak force mode atomic force microscopy. It is found that the block ionomer complex possesses a higher average elastic modulus after complexation with crystallizable APCL. Additionally, the moduli for both hard and soft phases increase and the phase with higher modulus assignable to the hard SPS component shows much more pronounced changes after complexation, confirming that APCL interacts mainly with the SPS blocks. This provides an understanding of the composition and nanomechanical properties of these new block ionomer complexes and an alternative insight into the micro-phase structures of multi-phase materials.