The Effect of Sizing on the Weavability of Cotton Yarns—Reply

An account is given of a study of the behaviour of three basic wool weft-knitted structures when subjected to ‘shear at constant length of sides’.

It was found that all the weft-knitted structures studied had a relatively low over-all shear-resistance when compared with other textile structures, such as woven and non-woven fabrics. This low over-all resistance was found to be a combination of a relatively large frictional restraint and a very low resistance once frictional slippage had started. These and other effects are discussed in terms of the geometrical changes occurring within the knitted unit cell during shearing.     

Type D personality and the development of PTSD symptoms: A prospective study.

Psychological trauma and prolonged stress may cause mental disorders such as posttraumatic stress disorder (PTSD). Pretrauma personality is an important determinant of posttraumatic adjustment. Specifically, trait neuroticism has been identified as a risk factor for PTSD. Additionally, the combination of high negative affectivity or neuroticism with marked social inhibition or introversion, also called Type D personality (Denollet, 2000), may compose a risk factor for PTSD. There is no research available that examined pretrauma Type D personality in relation to PTSD. The present study examined the predictive validity of the Type D personality construct in a sample of Dutch soldiers. Data were collected prior to and 6 months after military deployment to Afghanistan. Separate multiple regression analyses were performed to examine the predictive validity of Type D personality. First, Type D personality was defined as the interaction between negative affect and social inhibition (Na × Si). In a second analysis, Type D was defined following cutoff criteria recommended by Denollet (2000). Results showed that negative affectivity was a significant predictor of PTSD symptoms. Social inhibition and the interaction Na × Si did not add to the amount of explained variance in postdeployment PTSD scores over the effects of childhood abuse, negative affectivity, and prior psychological symptoms. A second analysis showed that Type D personality (dichotomous) did not add to the amount of explained variance in postdeployment PTSD scores over the effects of childhood abuse, and prior psychological symptoms. Therefore, Type D personality appears to be of limited value to explain development of combat-related PTSD symptoms. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Confrontations with aggression and mental health problems in police officers: The role of organizational stressors, life-events and previous mental health problems.

The extent to which the frequency of facing aggression incidents is associated with mental health problems among police officers when organizational stressors, life-events, and previous mental health problems are taken into account is unclear. To elucidate this data from a longitudinal study of police officers was analyzed (N = 473). Mental health problems (MHPs) are here defined as severe anxiety, depression, hostility, burnout symptoms, and/or sleeping problems according the SCL-90–R and MBI. All MHPs were assessed at baseline and 27 months later. Logistic regression showed that serious threat was statistically significant associated with MHPs at follow-up among officers without MHPs at baseline, but not among those with MHPs at baseline. However, stepwise logistic regression showed that serious threat and/or physical aggression were not independently associated with MHPs at follow-up. Organizational stressors, that is, problems with colleagues were independent predictors in all analyses. Among the total study sample, previous MHPs were the strongest independent predictors. These findings suggest superiors should attend to the mental health, organizational stressors and life-events of their officers regularly and not only following critical incidents at work. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A cash-constrained stochastic inventory model with consumer loans and supplier credits: the case of nanostores in emerging markets

We consider a small traditional retailer that is managing its inventory under strict cash constraints, mainly because typically informal loans are offered to customers. These stores are widely present in emerging markets, and we refer to them as nanostores (also called ‘mom-and-pop stores’). As the suppliers require immediate payments for goods delivered, a nanostore can only replenish products to the level for which it has on-hand cash available. To improve delivery efficiency, a supplier might offer a nanostore credit for its replenishments. However, currently, suppliers are often reluctant to do so as these nanostores quickly go bankrupt or disappear, hence defaulting on all outstanding credits. The objective of this paper is to determine when it is beneficial to offer supplier credits. We propose a multi-period, stochastic inventory model, and numerically compare scenarios with and without supplier credits. Our study shows that even in the presence of this risk, suppliers often have good incentives to provide these credits, even if interest is not incurred. For this to hold, the operations of the retailer should be (a little) profitable in the first place, for which we provide analytical conditions.     

Algorithmic Aspects of Proportional Symbol Maps

Proportional symbol maps visualize numerical data associated with point locations by placing a scaled symbol—typically an opaque disk or square—at the corresponding point on a map. The area of each symbol is proportional to the numerical value associated with its location. Every visually meaningful proportional symbol map will contain at least some overlapping symbols. These need to be drawn in such a way that the user can still judge their relative sizes accurately.     

Identifying multiple roles of ICT coordinators

This study reports on the development and validation of measurement scales to study the different roles fulfilled by ICT coordinators. Based on a review of the literature, a 24 item questionnaire was constructed and administered to a sample of 177 Flemish ICT coordinators working in primary education. Exploratory factor analysis revealed a four-factor solution: the ICT coordinator as a planner, a budgeter, a technician, and an educationalist. Qualitative data corroborated these roles. This study provides a quantitative measure of the different roles assumed by ICT coordinators in practice. The implications of our findings for schools, researchers and policy makers are discussed.     

On the applicability of the laminar flow index when selecting surgical lighting

In modern operating rooms ultraclean air is supplied through the ceiling to prevent bacteria from entering an operating wound and cause infections. Operating lamps can disturb this flow of clean air. In this paper the accuracy of some aspects of the Laminar Flow Index of operating lamps was tested. The disturbance of the airflow was determined for different shapes and sizes of operating lamps in an isothermal situation. To accomplish this, an experimental study and a simulation study of a small room with an operating lamp were performed. The infection risk was found to be proportional to the projected surface area of the lamp. Although different lamp shapes resulted in a distinctly different flow pattern in the room, this did not affect the infection risk in a significant way. Operating lamps with a projected area smaller than 0.1 m² do not disturb the airflow at all in this particular setup.     

Exploring the potential of recovering 1‐butanol from aqueous solutions by liquid demixing upon addition of carbohydrates or salts

BACKGROUND: Fermentative production of 1‐butanol yields dilute aqueous solutions. Recovery of the butanol from these solutions is most commonly performed by energy‐intensive distillation. This work investigated the liquid‐liquid (L‐L) phase behavior of mixtures of butanol and water to explore the potential of using L‐L phase separation as a recovery possibility for 1‐butanol. The phase behavior is preferably influenced by compounds already present in the fermentation, such as carbohydrates and salts. RESULTS: The L‐L phase equilibria of butanol and water were determined in the presence of glucose, fructose, sucrose, NaCl, LiCl and CaCl₂. The aqueous and organic phase split is more pronounced in the presence of salts than in the presence of carbohydrates. Demixing is achieved with about 0.3 kg salt kg^?1 aqueous phase containing 40 g of butanol. CONCLUSION: Operation of L‐L based recovery using salts or carbohydrates requires extreme concentrations of those compounds. For feed material containing 40 g kg^?1 butanol, the tested carbohydrates do not influence the phase equilibria sufficiently to allow butanol separation. Fermentative butanol concentrations up to 70 g kg^?1 are required to create an effective L‐L phase split. The remaining residual aqueous carbohydrate solution might be used as feed for a following fermentation. Copyright © 2011 Society of Chemical Industry