The influence of safety belt laws on self- reported safety belt use in the United States

We assessed rates and trends in safety belt use by presence and type of safety belt law using data from states participating in the 1984–1989 Behavioral Risk Factor Surveillance System. State(s) with a safety belt law allowing law enforcement officers to stop vehicles for occupants' failure to use safety belts (primary enforcement law) had greater and more rapid increases in safety belt use rates than did states with laws requiring that vehicles must first be stopped for some other violation before a citation or fine for occupants' failure to use safety belts could be imposed (secondary enforcement law). Larger and sustained increases in safety belt use occurred when safety belt laws became effective or when fines were imposed for violations than when laws were first enacted. These data suggest that primary enforcement laws result in greater and more rapid increases in safety belt use than do secondary enforcement laws, and that initial increases in safety belt use following implementation of laws are sustained.     

Audio watermarking under desynchronization and additive noise attacks

Digital watermarking is often modeled as the transmission of a message over a noisy channel denoted as "watermark channel". Distortions introduced by the watermark channel result mainly from attacks and may include interference from the original signal. One of the main differences with classical transmission situations stems from the fact that perceived distortions have to be taken into account. However, measuring the perceived impact an attack has on a watermarked signal is currently an unsolved problem. Possible means of circumventing this problem would be 1) to define the distortion in a so-called "perceived domain" and define an "ad hoc" equivalence between objective and perceived distortion or 2) to define an "equivalent distortion" by removing from the attack noise the part that is correlated to the host signal. This paper concentrates on the second approach and first shows that the resulting "equivalent" attack is a particular case of a thoroughly studied channel: filtering plus additive noise. However, the approach in this paper emphasizes the fact that the additive noise in the model has to be decorrelated with the signal. Then, the formalism is applied to (desynchronization plus noise) attacks on audio signals. In this context, this paper provides the corresponding capacities, as well as optimal "attack" and "defense" strategies in a game theory context.     

Some estimators of finite population variance using information on two auxiliary variables

Some estimators using information on two auxiliary variables for finite population variance are proposed, their bias and mean square error (MSE) are found, and their properties are analysed. As an illustration, an empirical study is also included.     

Alkyl Substituent Effects on the Conductivity of Polyaniline

The oxidative polymerization of aniline hydrochloride derivatives in water at low temperature is studied without lithium chloride. The resulting polymers have high molecular weight but the conductivity of the acid‐doped films is strongly dependent on the alkyl‐substituted chain at the 2‐positions. The root cause of the alkyl‐substitution effects is thoroughly investigated using density functional theory (DFT) methods (B3LYP using 6–1G(d,p) and 6‐311++G(2d,2p) basis sets). Internal structural changes observed on substitution appear to be more significant than a variety of electronic parameters measured using the natural bond orbital (NBO) method. Interplanar angles steadily increase on substitution, whereas ring orbital properties and the amount of ring delocalization remain fairly constant. An investigation into the extent to which lone pair–σ‐orbital overlap is affected by substitution indicates that increasing the steric bulk of the substituent reduces the ability of the lone pair to delocalize into the ring orbitals. However, the amount of overlap between the two is not adversely affected until the dihedral between them is > 30°, a situation that only occurs in i‐propyl and s‐butyl substitution. This finding is completely reflected in the experimental conductivity measurements.     

The use of a multipurpose stent in children

OBJECTIVES: To assess the use of a multipurpose stent (the 'Blue stent', Angiomed Urosoft Pyeloplasty Stent, Bard, UK) in children undergoing pyeloplasty and ureteric reimplantation. PATIENTS AND METHODS: Between August 1994 and August 1996, the Blue stent was used in 50 renal units in 46 children aged 2 months to 12 years and 6 months. Twenty-five children underwent pyeloplasty, 11 had ureteric reimplantation for vesico-ureteric reflux (VUR), eight had ureteric reimplantation with remodelling for obstructed megaureters and in two patients it was used during the removal of stones. The mean follow-up was 18 months (range 6-30 months). RESULTS: After pyeloplasty, 22 patients (88%) had improved renal function and drainage with a decrease in hydronephrosis; two patients had a decrease in hydronephrosis only, one had an anastomotic leak and needed a repeat pyeloplasty and four developed a urinary tract infection (UTI). After ureteric reimplantation, VUR was not detected in any patient. Two patients had no change in drainage after remodelling and reimplantation of a megaureter, one was later diagnosed as having a neuropathic bladder and one child developed a UTI after ureteric reimplantation. The hospital stay was 3 days after pyeloplasty and 5 days after reimplantation. CONCLUSION: The design of the multipurpose Blue stent provides versatility; it can be used as a stent, and both an internal and external drain. Its use does not prolong the hospital stay. Insertion causes minimal trauma to the renal parenchyma, and removal is easy, pain-free and requires no anaesthesia. The complication rates in the present series compare favourably with other reported series.     

Human immunodeficiency virus partner notification. Cost and effectiveness data from an attempted randomized controlled trial

OBJECTIVE: Determine the cost and effectiveness of partner notification for human immunodeficiency virus (HIV) infection. METHODS: Persons testing HIV positive in three areas were randomly assigned one of four approaches to partner notification. Analysis plans changed because disease intervention specialists notified many partners from the patient referral group. We dropped the patient referral group and combined the others to assess the cost and effectiveness of provider referral. RESULTS: The 1,070 patients reported 8,633 partners. Of those 1,035 were located via record search or in person. A previous positive test was reported by 248 partners. Of the 787 others, 560 were tested: 438 were HIV negative and 122 were newly identified as HIV positive. The intervention specialist's time totaled 197 minutes per index patient. The cost of the intervention specialist's time, travel, and overhead was $268,425: $251 per index patient, $427 per partner notified, or $2,200 per new HIV infection identified. No demographic characteristic of the index patient strongly predicted the likelihood of finding an infected partner. CONCLUSION: We could not compare the effectiveness of different partner notification approaches because of frequent crossover between randomized groups. The cost of partner notification can be compared with other approaches to acquired immunodeficiency syndrome prevention, but the benefits are not easily measured. We do not know the number of HIV cases prevented or the value of fulfilling the ethical obligation to warn partners of a potential threat to their health.     

Effects of kinetic and transport parameters on accelerated migration of reactive additive from plastic sheet

The effects of kinetic parameters Hatta number Ha and ?, and transport parameters Biot number Bi and ψ on the migration of a reactive additive have been modeled. The convective boundary layer can be considered inert to fully reactive for Ha → 0 to 2, respectively. The migration is controlled by diffusion, reaction rate, equilibrium partitioning of the migrant between the plastic film and the solvent, and boundary layer resistance, depending on the time scale and values of the above parameters. For a nonreactive boundary layer, at high Bi, migration is initially diffusion-controlled but becomes reaction-rate controlled at later times. However, under similar conditions, a slight increase in the reactivity of the boundary layer immediately changes the transport process from diffusion-controlled to reaction rate-controlled. With further increase in reactivity, migration spontaneously reaches equilibrium. At low Bi, equilibrium partitioning and reactive depletion of the migrant in the fluid phase change predominantly to boundary layer-controlling mass transport phenomenon. For a given sampling time (τ = 1.0), the migration increases with the increase in Bi only for a reactive boundary layer. At low Bi and (τ = 1.0), migration decreases only up to ? ? 0.3 for nonreactive to partially reactive boundary layer, but for intermediate and high Bi, ? and Ha do not influence migration.     

Effect of core–shell rubber toughening on mechanical,thermal, and morphological properties of poly(lactic acid)/multiwalled carbon nanotubes nanocomposites

The effect of core–shell rubber (CSR) toughening on mechanical and thermal properties of poly(lactic acid)/multiwalled carbon nanotubes (PLA/CNT) nanocomposites were investigated. The nanocomposites were prepared by direct melt blending method in a counter-rotating twin-screw extruder. The contents of CSR were varied between 5 and 20 wt % while the content of CNT was kept at 5 phr. The extruded samples were injection molded into the desired test specimens for mechanical and thermal properties analysis. The impact strength of PLA/CNT increased with increasing CSR content with concomitant decrease in tensile strength and modulus. Interestingly, the flexural strength increased at low CSR content before decreasing at 15 and 20% content. Differential scanning calorimetry analysis on the second heating cycle shows no crystallinity content for PLA/CNT and all CSR toughened PLA/CNT nanocomposites, while thermogravimetric analysis shows lower thermal degradation of all CSR toughened PLA/CNT as compared to PLA/CNT nanocomposite. This study reveals significant correlation between CSR loading with the mechanical and thermal properties of the nanocomposites. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47756.