Solitary and shock waves in discrete double power-law materials

A novel strongly nonlinear laminar metamaterial supporting new types of solitary and shock waves with impact energy mitigating capabilities is presented. It consists of steel plates with intermittent polymer toroidal rings acting as strongly nonlinear springs with large allowable strain. Their force-displacement relationship is described by the addition of two power-law relationships resulting in a solitary wave speed and width depending on the amplitude. This double nonlinearity allows splitting of an initial impulse into two separate strongly nonlinear solitary wave trains. Solitary and shock waves are observed experimentally and analyzed numerically in an assembly with Teflon o-rings.Comment: 14 pages, 6 figure

Gameplay experience in a gaze interaction game

Assessing gameplay experience for gaze interaction games is a challenging task. For this study, a gaze interaction Half-Life 2 game modification was created that allowed eye tracking control. The mod was deployed during an experiment at Dreamhack 2007, where participants had to play with gaze navigation and afterwards rate their gameplay experience. The results show low tension and negative affects scores on the gameplay experience questionnaire as well as high positive challenge, immersion and flow ratings. The correlation between spatial presence and immersion for gaze interaction was high and yields further investigation. It is concluded that gameplay experience can be correctly assessed with the methodology presented in this paper.Comment: pages 49-54, The 5th Conference on Communication by Gaze Interaction - COGAIN 2009: Gaze Interaction For Those Who Want It Most, ISBN: 978-87-643-0475-

Trends and Techniques in Visual Gaze Analysis

Visualizing gaze data is an effective way for the quick interpretation of eye tracking results. This paper presents a study investigation benefits and limitations of visual gaze analysis among eye tracking professionals and researchers. The results were used to create a tool for visual gaze analysis within a Master's project.Comment: pages 89-93, The 5th Conference on Communication by Gaze Interaction - COGAIN 2009: Gaze Interaction For Those Who Want It Most, ISBN: 978-87-643-0475-

Cosmology in a supersymmetric model with gauged B−LB-L

We consider salient cosmological features of a supersymmetric model which is Left-Right symmetric and therefore possessing gauged $B-L$ symmetry. The requirement of breaking parity and also obtaining charge preserving vacua introduces some unique features to this model (MSLRM), resulting in a preference for non-thermal Leptogenesis. Assuming that the model preserves TeV scale supersymmetry, we show that the vacuum structure generically possesses domain walls, which can serve two important purposes. They can signal a secondary inflation required to remove unwanted relics such as gravitino and moduli and also generate lepton asymmetry by a mechanism similar to electroweak baryogenesis. The requirement of disappearance of domain walls imposes constraints on the soft parameters of the theory, testable at the TeV scale. We also propose an alternative model with spontaneous parity violation (MSLR\rlap/P). Incorporating the same cosmological considerations in this case entails constraints on a different set of soft parameters.Comment: 18 pages. Minor changes in text, but conclusion remains same. Published in Phys. Rev.

Management of Fluid Status in Haemodialysis Patients: The Roles of Technology and Dietary Advice, Technical Problems in Patients on Hemodialysis

The kidneys play a vital role in maintaining normal tissue hydration and serum sodium level. In haemodialysis patients, with impaired or absent kidney function, fluid status is managed by removing excess fluid using ultrafiltration and by restricting dietary sodium intake. Ideally, haemodialysis patients should remain close to normal hydration throughout the interdialytic period, with minimal periods of excessive dehydration or fluid overload and with no fluid–related co-morbidity. Optimal fluid management is achieved by adjusting the post-dialysis ‘target’ weight and, where necessary, limiting the fluid gained between dialysis sessions. While clinical history and examination remain the basis for prescribing the target weight, technology can provide useful objective information especially where the clinical indications are ambiguous. A simple non-invasive test can now be carried out when a patient attends for dialysis enabling staff to pick up changes in body composition so that their target weight can be adjusted to maintain optimal fluid status. In most patients, interdialytic fluid gain (IDFG) is directly related to sodium intake. Acceptable fluid gains can usually be achieved by limiting salt intake to the recommended daily allowance for the general population and avoiding unnecessary sodium loading during dialysis. Low pre-dialysis serum sodium levels can help identify patients with other causes of high IDFG, such as high blood sugar or social drinking, who need additional counselling. For the patients, lowering sodium intake may also improve blood pressure control and reduce requirements for antihypertensive medication. Staff education, and preferably participation, is vital when implementing salt restriction in a haemodialysis unit

A profile of children with complex chronic conditions at end of life among Medicaid beneficiaries: Implications for health care reform

Background: As the United States braces for full implementation of health care reform, the eyes of the nation are on Medicaid. The large number of newly eligible Medicaid beneficiaries may challenge health care resources and ultimately impact quality of care. This is a special concern among current Medicaid beneficiaries such as children with complex chronic conditions (CCCs) who have significant health care needs, especially at end of life (EOL). Yet, a comprehensive profile of these children is lacking. Objective: To understand the demographic and health characteristics, health care utilization, and expenditures among Medicaid children with CCCs at EOL. Methods: Our study used a retrospective cohort design with data from the 2007 and 2008 California Medicaid data files. Descriptive statistics were used to profile children in the last year of life. Results: We found a diverse group of children who suffered with serious, multiple chronic conditions, and who accessed comprehensive, multidisciplinary care. Most children had neuromuscular conditions (54%), cardiovascular conditions (46%), and cancer (30%). A majority (56%) had multiple CCCs. Children with CCCs received comprehensive care including hospital inpatient (67%), primary (82%), ancillary (87%), and other acute care services (83%); however, few children utilized hospice and home health care services (26%). Significant age differences existed among the children. Conclusions: The current California Medicaid system appears to provide comprehensive care for children at EOL. The underutilization of hospice and home health services, however, represents an opportunity to improve the quality of EOL care while potentially reducing or remaining budget neutral

Tiperon

A control surface for an air vehicle (e.g., an aircraft, rocket, or missile) is useful for flight control at both subsonic and supersonic speeds. The control surface defines the outboardmost tip of a flight structure (e.g., a wing, tail or other stabilizer) of the air vehicle. Hence, the control surface is referred to as a `tiperon`. The tiperon has an approximately L-shaped configuration, and can be rotated relative to a fixed portion of the flight structure about a control axis. The respective surface areas of the tiperon sections forward and aft of the control axis are proportioned to place the subsonic center of pressure aft of the control axis to enhance aircraft control, and preferably also forward of the centroid of tiperon surface area. Also, the control surface sections forward and aft of the control axis are preferably mass-balanced, or at least nearly so, to enhance aircraft control at supersonic speeds. Either of the tiperon sections forward and aft of the control axis can be tapered to reduce the dependence of the moment exerted by air flow about the control axis, upon the tiperon's angle-of-attack. The tiperon also has enough surface area to control the air vehicle, even at low airspeeds. The invention is also directed to air vehicles incorporating one or more such control surfaces

IDWG, salt and water – an audit of dialysis staff. British Journal of Renal Medicine.

Our haemodialysis service comprises two teaching hospital-based centres and six satellite units, which merged some years ago. The teaching hospitals were traditionally managed by separate groups of dietitians and dialysis staff. Consequently, there were differences in practice within the service, including the methods used to determine an acceptable interdialytic weight gain (IDWG). High IDWG is regarded as a negative factor due to associated intradialytic hypotension, interdialytic hypertension and cardiovascular disease.1 As such, patients with excessive IDWG are frequently advised to limit their daily fluid intake and may be encouraged to reduce their salt intake because of the association between salt intake and thirst.2 Different members of the multidisciplinary team (MDT) act as advisors in this area. This may lead to confusion and non-compliance if the information is conflicting or provided in a negative manner.3 We undertook an audit throughout the haemodialysis service to standardise the advice given to patients. This article reports the results of a questionnaire used to determine how staff respond to excessive IDWG. It also examined their knowledge of the salt and fluid content of common foods