Layered titanate nanofibers as efficient adsorbents for removal of toxic radioactive and heavy metal ions from water

Titanate nanofibers with two formulas, Na2Ti3O7 and Na1.5H0.5Ti3O7, respectively, exhibit ideal properties for removal of radioactive and heavy metal ions in wastewater, such as Sr2+ , Ba2+ (as substitute of 226Ra2+), and Pb2+ ions. These nanofibers can be fabricated readily by a reaction between titania and caustic soda and have structures in which TiO6 octahedra join each other to form layers with negative charges; the sodium cations exist within the interlayer regions and are exchangeable. They can selectively adsorb the bivalent radioactive ions and heavy metal ions from water through ion exchange process. More importantly, such sorption finally induces considerable deformation of the layer structure, resulting in permanent entrapment of the toxic bivalent cations in the fibers so that the toxic ions can be safely deposited. This study highlights that nanoparticles of inorganic ion exchangers with layered structure are potential materials for efficient removal of the toxic ions from contaminated water.

Does pornography harm young people?

In recent debates about the regulation of technologies that deliver pornographic content, the greatest concerns have been about the increasing ease with which young people can access such material. Because of the ethical difficulties in researching this topic, little data has been available on the potential harm done to young people by exposure to pornography. This paper gathers a number of data sources that address this issue indirectly—including the results of our own survey of over 1000 consumers of pornography—to explore this issue. Research shows that healthy sexual development includes natural curiosity about sexuality. Retrospective studies show that accidental exposure to real-life scenes of sexuality does not harm children. Our survey shows that age of first exposure to pornography does not correlate with negative attitudes towards women. Studies with non-explicit representations of sexuality show that young people who seek out sexualised representations tend to be those with a pre-existing interest in sexuality. These studies also suggest that current generations of children are no more sexualised than previous generations, that they are not innocent about sexuality, and that a key negative effect of this knowledge is the requirement for them to feign ignorance in order to satisfy adults’ expectations of them. Research also suggests important differences between pre- and post-pubescent attitudes towards pornography, and that pornography is not addictive.

Local Rademacher complexities

We propose new bounds on the error of learning algorithms in terms of a data-dependent notion of complexity. The estimates we establish give optimal rates and are based on a local and empirical version of Rademacher averages, in the sense that the Rademacher averages are computed from the data, on a subset of functions with small empirical error. We present some applications to classification and prediction with convex function classes, and with kernel classes in particular.

The influence of online reviews on consumers’ attributions of service quality and control for service standards in hotels

Online travel reviews are emerging as a powerful source of information affecting tourists' pre-purchase evaluation of a hotel organization. This trend has highlighted the need for a greater understanding of the impact of online reviews on consumer attitudes and behaviors. In view of this need, we investigate the influence of online hotel reviews on consumers' attributions of service quality and firms' ability to control service delivery. An experimental design was used to examine the effects of four independent variables: framing; valence; ratings; and target. The results suggest that in reviews evaluating a hotel, remarks related to core services are more likely to induce positive service quality attributions. Recent reviews affect customers' attributions of controllability for service delivery, with negative reviews exerting an unfavorable influence on consumers' perceptions. The findings highlight the importance of managing the core service and the need for managers to act promptly in addressing customer service problems.

‘Connect and create’ : young people, YouTube and graffiti communities

Dominant discourses around young people and social networking in the mass media are littered with negative connotations and moral panics. While some scholars challenge this negativity, their focus has predominantly been upon the formation of friendships, the construction of identity and the presentation of the self online. We argue that as well as engaging in such areas, young people are also appropriating social networking sites, such as YouTube, as spaces in which they can engage in what Jean Burgess terms, ‘Vernacular Creativity’ – a way of describing and surfacing creative practices that emerge from non-elite, specific everyday contexts. Using case study material we consider the processes of Vernacular Creativity as engaged with by young people in relation to doing graffiti with YouTube. Through this, and given that graffiti is a cultural practise traditionally associated with physical space, we also consider points of continuity and discontinuity in relation to Vernacular Creativity mediated with YouTube and the significance of such things in enabling young people to connect and create with like-minded others.

Inflow cannula design for biventricular assist devices

Cardiovascular diseases are a leading cause of death throughout the developed world. With the demand for donor hearts far exceeding the supply, a bridge-to-transplant or permanent solution is required. This is currently achieved with ventricular assist devices (VADs), which can be used to assist the left ventricle (LVAD), right ventricle (RVAD), or both ventricles simultaneously (BiVAD). Earlier generation VADs were large, volume-displacement devices designed for temporary support until a donor heart was found. The latest generation of VADs use rotary blood pump technology which improves device lifetime and the quality of life for end stage heart failure patients. VADs are connected to the heart and greater vessels of the patient through specially designed tubes called cannulae. The inflow cannulae, which supply blood to the VAD, are usually attached to the left atrium or ventricle for LVAD support, and the right atrium or ventricle for RVAD support. Few studies have characterized the haemodynamic difference between the two cannulation sites, particularly with respect to rotary RVAD support. Inflow cannulae are usually made of metal or a semi-rigid polymer to prevent collapse with negative pressures. However suction, and subsequent collapse, of the cannulated heart chamber can be a frequent occurrence, particularly with the relatively preload insensitive rotary blood pumps. Suction events may be associated with endocardial damage, pump flow stoppages and ventricular arrhythmias. While several VAD control strategies are under development, these usually rely on potentially inaccurate sensors or somewhat unreliable inferred data to estimate preload. Fixation of the inflow cannula is usually achieved through suturing the cannula, often via a felt sewing ring, to the cannulated chamber. This technique extends the time on cardiopulmonary bypass which is associated with several postoperative complications. The overall objective of this thesis was to improve the placement and design of rotary LVAD and RVAD inflow cannulae to achieve enhanced haemodynamic performance, reduced incidence of suction events, reduced levels of postoperative bleeding and a faster implantation procedure. Specific objectives were: * in-vitro evaluation of LVAD and RVAD inflow cannula placement, * design and in-vitro evaluation of a passive mechanism to reduce the potential for heart chamber suction, * design and in-vitro evaluation of a novel suture-less cannula fixation device. In order to complete in-vitro evaluation of VAD inflow cannulae, a mock circulation loop (MCL) was developed to accurately replicate the haemodynamics in the human systemic and pulmonary circulations. Validation of the MCL’s haemodynamic performance, including the form and magnitude of pressure, flow and volume traces was completed through comparisons of patient data and the literature. The MCL was capable of reproducing almost any healthy or pathological condition, and provided a useful tool to evaluate VAD cannulation and other cardiovascular devices. The MCL was used to evaluate inflow cannula placement for rotary VAD support. Left and right atrial and ventricular cannulation sites were evaluated under conditions of mild and severe heart failure. With a view to long term LVAD support in the severe left heart failure condition, left ventricular inflow cannulation was preferred due to improved LVAD efficiency and reduced potential for thrombus formation. In the mild left heart failure condition, left atrial cannulation was preferred to provide an improved platform for myocardial recovery. Similar trends were observed with RVAD support, however to a lesser degree due to a smaller difference in right atrial and ventricular pressures. A compliant inflow cannula to prevent suction events was then developed and evaluated in the MCL. As rotary LVAD or RVAD preload was reduced, suction events occurred in all instances with a rigid inflow cannula. Addition of the compliant segment eliminated suction events in all instances. This was due to passive restriction of the compliant segment as preload dropped, thus increasing the VAD circuit resistance and decreasing the VAD flow rate. Therefore, the compliant inflow cannula acted as a passive flow control / anti-suction system in LVAD and RVAD support. A novel suture-less inflow cannula fixation device was then developed to reduce implantation time and postoperative bleeding. The fixation device was evaluated for LVAD and RVAD support in cadaveric animal and human hearts attached to a MCL. LVAD inflow cannulation was achieved in under two minutes with the suture-less fixation device. No leakage through the suture-less fixation device – myocardial interface was noted. Continued development and in-vivo evaluation of this device may result in an improved inflow cannulation technique with the potential for off-bypass insertion. Continued development of this research, in particular the compliant inflow cannula and suture-less inflow cannulation device, will result in improved postoperative outcomes, life span and quality of life for end-stage heart failure patients.

Investigating the impact of a leadership development program for nurse unit managers on the satisfaction of nursing staff

Background and significance: Nurses' job dissatisfaction is associated with negative nursing and patient outcomes. One of the most powerful reasons for nurses to stay in an organisation is satisfaction with leadership. However, nurses are frequently promoted to leadership positions without appropriate preparation for the role. Although a number of leadership programs have been described, none have been tested for effectiveness, using a randomised control trial methodology. Aims: The aims of this research were to develop an evidence based leadership program and to test its effectiveness on nurse unit managers' (NUMs') and nursing staff's (NS's) job satisfaction, and on the leader behaviour scores of nurse unit managers. Methods: First, the study used a comprehensive literature review to examine the evidence on job satisfaction, leadership and front-line manager competencies. From this evidence a summary of leadership practices was developed to construct a two component leadership model. The components of this model were then combined with the evidence distilled from previous leadership development programs to develop a Leadership Development Program (LDP). This evidence integrated the program's design, its contents, teaching strategies and learning environment. Central to the LDP were the evidence-based leadership practices associated with increasing nurses' job satisfaction. A randomised controlled trial (RCT) design was employed for this research to test the effectiveness of the LDP. A RCT is one of the most powerful tools of research and the use of this method makes this study unique, as a RCT has never been used previously to evaluate any leadership program for front-line nurse managers. Thirty-nine consenting nurse unit managers from a large tertiary hospital were randomly allocated to receive either the leadership program or only the program's written information about leadership. Demographic baseline data were collected from participants in the NUM groups and the nursing staff who reported to them. Validated questionnaires measuring job satisfaction and leader behaviours were administered at baseline, at three months after the commencement of the intervention and at six months after the commencement of the intervention, to the nurse unit managers and to the NS. Independent and paired t-tests were used to analyse continuous outcome variables and Chi Square tests were used for categorical data. Results: The study found that the nurse unit managers' overall job satisfaction score was higher at 3-months (p = 0.016) and at 6-months p = 0.027) post commencement of the intervention in the intervention group compared with the control group. Similarly, at 3-months testing, mean scores in the intervention group were higher in five of the six "positive" sub-categories of the leader behaviour scale when compared to the control group. There was a significant difference in one sub-category; effectiveness, p = 0.015. No differences were observed in leadership behaviour scores between groups by 6-months post commencement of the intervention. Over time, at three month and six month testing there were significant increases in four transformational leader behaviour scores and in one positive transactional leader behaviour scores in the intervention group. Over time at 3-month testing, there were significant increases in the three leader behaviour outcome scores, however at 6-months testing; only one of these leader behaviour outcome scores remained significantly increased. Job satisfaction scores were not significantly increased between the NS groups at three months and at six months post commencement of the intervention. However, over time within the intervention group at 6-month testing there was a significant increase in job satisfaction scores of NS. There were no significant increases in NUM leader behaviour scores in the intervention group, as rated by the nursing staff who reported to them. Over time, at 3-month testing, NS rated nurse unit managers' leader behaviour scores significantly lower in two leader behaviours and two leader behaviour outcome scores. At 6-month testing, over time, one leader behaviour score was rated significantly lower and the nontransactional leader behaviour was rated significantly higher. Discussion: The study represents the first attempt to test the effectiveness of a leadership development program (LDP) for nurse unit managers using a RCT. The program's design, contents, teaching strategies and learning environment were based on a summary of the literature. The overall improvement in role satisfaction was sustained for at least 6-months post intervention. The study's results may reflect the program's evidence-based approach to developing the LDP, which increased the nurse unit managers' confidence in their role and thereby their job satisfaction. Two other factors possibly contributed to nurse unit managers' increased job satisfaction scores. These are: the program's teaching strategies, which included the involvement of the executive nursing team of the hospital, and the fact that the LDP provided recognition of the importance of the NUM role within the hospital. Consequently, participating in the program may have led to nurse unit managers feeling valued and rewarded for their service; hence more satisfied. Leadership behaviours remaining unchanged between groups at the 6 months data collection time may relate to the LDP needing to be conducted for a longer time period. This is suggested because within the intervention group, over time, at 3 and 6 months there were significant increases in self-reported leader behaviours. The lack of significant changes in leader behaviour scores between groups may equally signify that leader behaviours require different interventions to achieve change. Nursing staff results suggest that the LDP's design needs to consider involving NS in the program's aims and progress from the outset. It is also possible that by including regular feedback from NS to the nurse unit managers during the LDP that NS's job satisfaction and their perception of nurse unit managers' leader behaviours may alter. Conclusion/Implications: This study highlights the value of providing an evidence-based leadership program to nurse unit managers to increase their job satisfaction. The evidence based leadership program increased job satisfaction but its effect on leadership behaviour was only seen over time. Further research is required to test interventions which attempt to change leader behaviours. Also further research on NS' job satisfaction is required to test the indirect effects of LDP on NS whose nurse unit managers participate in LDPs.

A fuzzy TOPSIS based multi criteria performance measurement model for lean supply chain

Increasing global competition, rapid technological changes, advances in manufacturing and information technology and discerning customers are forcing supply chains to adopt improvement practices that enable them to deliver high quality products at a lower cost and in a shorter period of time. A lean initiative is one of the most effective approaches toward achieving this goal. In the lean improvement process, it is critical to measure current and desired performance level in order to clearly evaluate the lean implementation efforts. Many attempts have tried to measure supply chain performance incorporating both quantitative and qualitative measures but failed to provide an effective method of measuring improvements in performances for dynamic lean supply chain situations. Therefore, the necessity of appropriate measurement of lean supply chain performance has become imperative. There are many lean tools available for supply chains; however, effectiveness of a lean tool depends on the type of the product and supply chain. One tool may be highly effective for a supply chain involved in high volume products but may not be effective for low volume products. There is currently no systematic methodology available for selecting appropriate lean strategies based on the type of supply chain and market strategy This thesis develops an effective method to measure the performance of supply chain consisting of both quantitative and qualitative metrics and investigates the effects of product types and lean tool selection on the supply chain performance Supply chain performance matrices and the effects of various lean tools over performance metrics mentioned in the SCOR framework have been investigated. A lean supply chain model based on the SCOR metric framework is then developed where non- lean and lean as well as quantitative and qualitative metrics are incorporated in appropriate metrics. The values of appropriate metrics are converted into triangular fuzzy numbers using similarity rules and heuristic methods. Data have been collected from an apparel manufacturing company for multiple supply chain products and then a fuzzy based method is applied to measure the performance improvements in supply chains. Using the fuzzy TOPSIS method, which chooses an optimum alternative to maximise similarities with positive ideal solutions and to minimise similarities with negative ideal solutions, the performances of lean and non- lean supply chain situations for three different apparel products have been evaluated. To address the research questions related to effective performance evaluation method and the effects of lean tools over different types of supply chains; a conceptual framework and two hypotheses are investigated. Empirical results show that implementation of lean tools have significant effects over performance improvements in terms of time, quality and flexibility. Fuzzy TOPSIS based method developed is able to integrate multiple supply chain matrices onto a single performance measure while lean supply chain model incorporates qualitative and quantitative metrics. It can therefore effectively measure the improvements for supply chain after implementing lean tools. It is demonstrated that product types involved in the supply chain and ability to select right lean tools have significant effect on lean supply chain performance. Future study can conduct multiple case studies in different contexts.

Pupil shape as viewed along the horizontal visual field

Purpose: Changes in pupil size and shape are relevant for peripheral imagery by affecting aberrations and how much light enters and/or exits the eye. The purpose of this study is to model the pattern of pupil shape across the complete horizontal visual field and to show how the pattern is influenced by refractive error. Methods: Right eyes of thirty participants were dilated with 1% cyclopentolate and images were captured using a modified COAS-HD aberrometer alignment camera along the horizontal visual field to ±90°. A two lens relay system enabled fixation at targets mounted on the wall 3m from the eye. Participants placed their heads on a rotatable chin rest and eye rotations were kept to less than 30°. Best-fit elliptical dimensions of pupils were determined. Ratios of minimum to maximum axis diameters were plotted against visual field angle. Results: Participants’ data were well fitted by cosine functions, with maxima at (–)1° to (–)9° in the temporal visual field and widths 9% to 15% greater than predicted by the cosine of the field angle . Mean functions were 0.99cos[( + 5.3)/1.121], R2 0.99 for the whole group and 0.99cos[( + 6.2)/1.126], R2 0.99 for the 13 emmetropes. The function peak became less temporal, and the width became smaller, with increase in myopia. Conclusion: Off-axis pupil shape changes are well described by a cosine function which is both decentered by a few degrees and flatter by about 12% than the cosine of the viewing angle, with minor influences of refraction.

Existence of travelling wave solutions for a model of tumour invasion

The existence of travelling wave solutions to a haptotaxis dominated model is analysed. A version of this model has been derived in Perumpanani et al. (1999) to describe tumour invasion, where diffusion is neglected as it is assumed to play only a small role in the cell migration. By instead allowing diffusion to be small, we reformulate the model as a singular perturbation problem, which can then be analysed using geometric singular perturbation theory. We prove the existence of three types of physically realistic travelling wave solutions in the case of small diffusion. These solutions reduce to the no diffusion solutions in the singular limit as diffusion as is taken to zero. A fourth travelling wave solution is also shown to exist, but that is physically unrealistic as it has a component with negative cell population. The numerical stability, in particular the wavespeed of the travelling wave solutions is also discussed.

Applying quantile regression for modeling equivalent property damage only crashes to identify accident blackspots

Hot spot identification (HSID) aims to identify potential sites—roadway segments, intersections, crosswalks, interchanges, ramps, etc.—with disproportionately high crash risk relative to similar sites. An inefficient HSID methodology might result in either identifying a safe site as high risk (false positive) or a high risk site as safe (false negative), and consequently lead to the misuse the available public funds, to poor investment decisions, and to inefficient risk management practice. Current HSID methods suffer from issues like underreporting of minor injury and property damage only (PDO) crashes, challenges of accounting for crash severity into the methodology, and selection of a proper safety performance function to model crash data that is often heavily skewed by a preponderance of zeros. Addressing these challenges, this paper proposes a combination of a PDO equivalency calculation and quantile regression technique to identify hot spots in a transportation network. In particular, issues related to underreporting and crash severity are tackled by incorporating equivalent PDO crashes, whilst the concerns related to the non-count nature of equivalent PDO crashes and the skewness of crash data are addressed by the non-parametric quantile regression technique. The proposed method identifies covariate effects on various quantiles of a population, rather than the population mean like most methods in practice, which more closely corresponds with how black spots are identified in practice. The proposed methodology is illustrated using rural road segment data from Korea and compared against the traditional EB method with negative binomial regression. Application of a quantile regression model on equivalent PDO crashes enables identification of a set of high-risk sites that reflect the true safety costs to the society, simultaneously reduces the influence of under-reported PDO and minor injury crashes, and overcomes the limitation of traditional NB model in dealing with preponderance of zeros problem or right skewed dataset.

THE quest for alpha : can artificial neural networks help?

The application of artificial neural networks (ANN) in finance is relatively new area of research. We employed ANNs that used both fundamental and technical inputs to predict future prices of widely held Australian stocks and used these predicted prices for stock portfolio selection over a 10-year period (2001-2011). We found that the ANNs generally do well in predicting the direction of stock price movements. The stock portfolios selected by the ANNs with median accuracy are able to generate positive alpha over the 10-year period. More importantly, we found that a portfolio based on randomly selected network configuration had zero chance of resulting in a significantly negative alpha but a 27% chance of yielding a significantly positive alpha. This is in stark contrast to the findings of the research on mutual fund performance where active fund managers with negative alphas outnumber those with positive alphas.

Sports participation and health-related behaviors among US youth

Objective To examine the relationship between sports participation and health-related behaviors among high school students. Design Cross-sectional design using data from the 1997 Centers for Disease Control and Prevention Youth Risk Behavior Survey. Participants A nationally representative sample of 14221 US high school students. Main Outcome Measures Prevalence of sports participation among males and females from 3 ethnic groups and its associations with other health behaviors, including diet, tobacco use, alcohol and illegal drug use, sexual activity, violence, and weight loss practices. Results Approximately 70% of male students and 53% of female students reported participating on 1 or more spores teams in school and/or nonschool settings; rates varied substantially by age, sex, and ethnicity. Male sports participants were more likely than male nonparticipants to report fruit and vegetable consumption on the previous day and less likely to report cigarette smelting, cocaine and other illegal drug use, and trying to lose weight. Compared with female nonparticipants, female sports participants were more likely to report consumption of vegetables on the previous day and less likely to report having sexual intercourse in the past 3 months. Among white males and females, several other beneficial health behaviors were associated with sports participation. A few associations with. negative health behaviors were observed in African American and Hispanic subgroups. Conclusion Sports participation is highly prevalent among US high school students, and is associated with numerous positive health behaviors and few negative health behaviors.

Double-authentication-preventing signatures

Digital signatures are often used by trusted authorities to make unique bindings between a subject and a digital object; for example, certificate authorities certify a public key belongs to a domain name, and time-stamping authorities certify that a certain piece of information existed at a certain time. Traditional digital signature schemes however impose no uniqueness conditions, so a trusted authority could make multiple certifications for the same subject but different objects, be it intentionally, by accident, or following a (legal or illegal) coercion. We propose the notion of a double-authentication-preventing signature, in which a value to be signed is split into two parts: a subject and a message. If a signer ever signs two different messages for the same subject, enough information is revealed to allow anyone to compute valid signatures on behalf of the signer. This double-signature forgeability property discourages signers from misbehaving---a form of self-enforcement---and would give binding authorities like CAs some cryptographic arguments to resist legal coercion. We give a generic construction using a new type of trapdoor functions with extractability properties, which we show can be instantiated using the group of sign-agnostic quadratic residues modulo a Blum integer.

Socio-emotional and operational demands on service employees

Enacting appropriate behaviors often requires service employees to suppress genuine emotions and/or express other emotions, genuine or contrived. Managing emotions to act in a socially appropriate manner constitutes a form of labor: emotional labor. If labor demands exceed the resources of the employee, burnout arises, with negative consequences for overall psychological well-being and job performance. Similarly, task related activities engender role stress, which can also lead to burnout. Both task related role demands and socio-emotional demands are likely to be omnipresent in interpersonal interactions in service settings. Accordingly, this study sets out to investigate the simultaneous impact of these job demands on burnout in front line service professionals. Based on survey data collected from allied health service workers, the study findings strongly suggest that both socio-emotional demands and task related role demands are significant determinants of workplace stress and that their simultaneous effects on employee burnout can be large.