A new algorithm to accelerate harmonic analysis of time series

The Lomb periodogram has been traditionally a tool that allows us to elucidate if a frequency turns out to be important for explaining the behaviour of a given time series. Many linear and nonlinear reiterative harmonic processes that are used for studying the spectral content of a time series take into account this periodogram in order to avoid including spurious frequencies in their models due to the leakage problem of energy from one frequency to others. However, the estimation of the periodogram requires long computation time that makes the harmonic analysis slower when we deal with certain time series. Here we propose an algorithm that accelerates the extraction of the most remarkable frequencies from the periodogram, avoiding its whole estimation of the harmonic process at each iteration. This algorithm allows the user to perform a specific analysis of a given scalar time series. As a result, we obtain a functional model made of (1) a trend component, (2) a linear combination of Fourier terms, and (3) the so-called mixed secular terms by reducing the computation time of the estimation of the periodogram.

Spanish Nursing Students' Practical Experience of Computer Applications in Nursing

This study aimed to determine the level of computer practical experience in a sample of Spanish nursing students. Each student was given a Spanish language questionnaire, modified from an original used previously with medical students at the Medical School of North Carolina University (USA) and also at the Education Unit of Hospital General Universitario del Mar (Spain). The 10-item self-report questionnaire probed for information about practical experience with computers. A total of 126 students made up the sample. The majority were female (80.2%; n=101). The results showed that just over half (57.1%, n=72) of the students had used a computer game (three or more times before), and that only one third (37.3%, n=47) had the experience of using a word processing package. Moreover, other applications and IT-based facilities (e.g. statistical packages, e-mail, databases, CD-ROM searches, programming languages and computer-assisted learning) had never been used by the majority of students. The student nurses' practical experience was less than that reported for medical students in previous studies.

Understanding sickness presenteeism through the experience of immigrant workers in a context of economic crisis

Background: Previous economic recessions show that immigrant workers may experience longer periods of unemployment, a situation that may lead employees to presenteeism, the act of working in spite of a health problem. This study explored perceptions about the factors that lead to presenteeism in immigrant workers considering the context of economic crisis. Methods: Six focus group discussions were held (February 2012), with men and women from Colombia, Ecuador, and Morocco (n = 44) living in Spain and selected by theoretical sample. A qualitative content analysis was performed. Results: Four categories were identified as factors that influence the occurrence of presenteeism in a context of economic crisis: poor employment conditions, fear of unemployment, employer/employee relationship, and difficulties in finding temporary replacement workers. Furthermore, musculoskeletal, respiratory, and mental problems were related to presenteeism. Conclusions: It is important to develop strategies to protect workers from negative working conditions that are associated with deterioration of health.

Estimation of Time-Limited Channel Spectra From Nonuniform Samples

This paper deals with the estimation of a time-invariant channel spectrum from its own nonuniform samples, assuming there is a bound on the channel’s delay spread. Except for this last assumption, this is the basic estimation problem in systems providing channel spectral samples. However, as shown in the paper, the delay spread bound leads us to view the spectrum as a band-limited signal, rather than the Fourier transform of a tapped delay line (TDL). Using this alternative model, a linear estimator is presented that approximately minimizes the expected root-mean-square (RMS) error for a deterministic channel. Its main advantage over the TDL is that it takes into account the spectrum’s smoothness (time width), thus providing a performance improvement. The proposed estimator is compared numerically with the maximum likelihood (ML) estimator based on a TDL model in pilot-assisted channel estimation (PACE) for OFDM.

Immigration experience of Latin American working women in Alicante, Spain: an ethnographic study

Objective: to describe the experience of Latin American working women regarding immigration, taking into account the expectations and conditions in which this process takes place. Method: ethnographic qualitative study. Data collection was performed by means of semi-structured interviews with 24 Latin American immigrant women in Spain. The information collected was triangulated through two focal groups. Results: the expectations of migrant women focus on improving family living conditions. Social support is essential for their settling and to perform daily life activities. They declare they have adapted to the settlement country, although they live with stress. They perceive they have greater sexual freedom and power with their partners but keep greater responsibility in childcare, combining that with the role of working woman. Conclusions: migrant women play a key role in the survival of households, they build and create new meanings about being a woman, their understanding of life, their social and couple relationships. Such importance is shaped by their expectations and the conditions in which the migration process takes place, as well as their work integration.