Sleep quality in nurses working in different shifts

The nursing staff who are working at hospitals with a shift-work scheduling might confront with sleep disorders related to the characteristics of nursing profession. The results of studies have ruled out the close relationship between life quality and health. It must be mentioned that the quality of life is affected by sleep pattern. The aim of this study was investigating sleep quality in nurses working in different shifts at hospitals affiliated to Zahedan University of Medical Sciences. A cross sectional study was conducted on 299 nurses who were working at general hospitals of Zahedan University of Medical Sciences in 2008. Pittsburgh sleep quality index was utilized to collect data. The data were analyzed in SPSS version 17. susing Mann-Whitney, Kruskal Wallis tests and Spearman correlation coefficient. The subjects were consist of 66 men (22.1%) and 233 women (77.9%) whit age mean 31.6± 6.6 years. The mean of work experience was 7.55± 6.8 years. The findings of study showed that sleep quality were suitable in only 55(17.1%) of nurses but 221(73.9%) of nurses have not sleepiness. The quality of life was high among only 32(10.7%) of nurses. In this study, quality of life has a relationship with sleep quality (P=.001, r=-.572) and sleepiness (P=.001, r=-.246). The sleep quality was related with gender, age, monthly income, disease, marital status and type of insurance. Also, the sleepiness was related to marital status and life quality was related to monthly income, disease, marital status and type of insurance P<0.05). This study showed that sleep quality is not suitable among nurses. Also, in this study the sleep pattern was related to quality of life, so lack of enough and suitable sleep will affected the quality of life, in turn, provided health care by nurses to patients and attendance would not be fair. Correcting and modification the sleep quality among nurses is very important. © 2015

Socioeconomic Factors and Water Quality in California

We investigate the relationships between water quality and socioeconomic factors in California at the county level for the years 1993 to 2006 using 24 water quality indicators coming from seven different types of water bodies. We estimate these relationships using three classes of models: the traditional per capita income-pollution level - Environmental Kuznets Curve (EKC) - specifications, a more inclusive model containing main socioeconomic variables such as agricultural intensity, land use, ethnic composition, population density and educational attainment, and a model that includes the socioeconomic variables while accounting for spatial correlations too. For most water quality indicators, we do not find support for EKC specifications. For pollutants like phosphorus and total suspended solids, the level of agricultural activity is a significant determinant of water quality in California, but for other surface water pollutants commonly considered agricultural pollutants, such as ammonia and nitrate, the level of agricultural activity is not statistically significant. We find that education, ethnic composition, age structure, land use, population density, and water area are all significantly correlated with various indicators of water quality.Water Quality Indicators, Socioeconomic Variables, EKC, Agriculture, Industry

A PORTFOLIO OF NUTRIENTS: SOIL AND SUSTAINABILITY

This paper develops a basic dynamic economic model that can be used for theoretical and numerical analysis of optimal soil management practices. A dynamic biophysical/economic optimal control model is developed in a multi-disciplinary framework, treating soil as a multi-pool portfolio of a particular limiting mobile nutrient (e.g. nitrogen). This specification allows for fertilizer to directly enter the active pool, while tillage initially affects the decadal pool, reflecting the realities of agricultural production. We examine the properties of the steady-state and the time paths of the optimal solutions. In addition, alternative sustainability criteria of farm-level agricultural practices are presented, and the optimal solution of the problem is evaluated to determine if it meets any or all of the definitions of sustainability.Farm Management,

An Investigation of the Ability to Recover from Transients Following Failures for Single-Pilot Rotorcraft

A moving-base simulation was conducted to investigate a pilot's ability to recover from transients following single-axis hard-over failures of the flight-control system. The investigation was performed in conjunction with a host simulation that examined the influence of control modes on a single pilot's ability to perform various mission elements under high-workload conditions. The NASA Ames large-amplitude-motion Vertical Motion Simulator (VMS) was utilized, and the experimental variables were the failure axis, the severity of the failure, and the airspeed at which the failure occurred. Other factors, such as pilot workload and terrain and obstacle proximity at the time of failure, were kept as constant as possible within the framework of the host simulation task scenarios. No explicit failure warnings were presented to the pilot. Data from the experiment are shown, and pilot ratings are compared with the proposed handling-qualities requirements for military rotorcraft. Results indicate that the current proposed failure transient requirements may need revision

On the Number of Nonnegative Solutions to the Inequality a1 +....ar < n

In this paper, we present a simple and fast method for counting the number of nonnegative integer solutions to the equality a1x1+a2x2+: : :+arxr = n where a1; a2; :::; ar and n are positive integers. As an application, we use the method for finding the number of solutions of a Diophantine inequality

Stability of Resonant Opto-Mechanical Oscillators

We theoretically study the frequency stability of an opto-mechanical radio frequency oscillator based on resonant interaction of two optical and one mechanical modes of the same optical microcavity. A generalized expression for the phase noise of the oscillator is derived using Langevin formalism and compared to the phase noise of existing electronic oscillators.Comment: 6 pages, 1 figur