Robust multivariate control charts based on Birnbaum–Saunders distributions

Multivariate control charts are powerful and simple visual tools for monitoring the quality of a process. This multivariate monitoring is carried out by considering simultaneously several correlated quality characteristics and by determining whether these characteristics are in control or out of control. In this paper, we propose a robust methodology using multivariate quality control charts for subgroups based on generalized Birnbaum–Saunders distributions and an adapted Hotelling statistic. This methodology is constructed for Phases I and II of control charts. We estimate the corresponding parameters with the maximum likelihood method and use parametric bootstrapping to obtain the distribution of the adapted Hotelling statistic. In addition, we consider the Mahalanobis distance to detect multivariate outliers and use it to assess the adequacy of the distributional assumption. A Monte Carlo simulation study is conducted to evaluate the proposed methodology and to compare it with a standard methodology. This study reports the good performance of our methodology. An illustration with real-world air quality data of Santiago, Chile, is provided. This illustration shows that the methodology is useful for alerting early episodes of extreme air pollution, thus preventing adverse effects on human health.     

Modeling wind energy flux by a Birnbaum–Saunders distribution with an unknown shift parameter

In this paper, we discuss a Birnbaum–Saunders distribution with an unknown shift parameter and apply it to wind energy modeling. We describe structural aspects of this distribution including properties, moments, mode and hazard and shape analyses. We also discuss estimation, goodness of fit and diagnostic methods for this distribution. A computational implementation in R language of the obtained results is provided. Finally, we apply such results to two unpublished real wind speed data from Chile, which allows us to show the characteristics of this statistical distribution and to model wind energy flux.     

Voluntary childlessness in a society reluctant to change

Voluntary childlessness constitutes a social and generational rupture from tradition and culture, with significant effects on the reproduction of the so-called life and family cycle. This study aims at understanding the reasons why people decide to remain childless and the social pressures that this decision generates. A qualitative phenomenological study was conducted on the emerging decision of non-motherhood and non-fatherhood based on semi-structured interviews with 56 people who autonomously made the decision to opt out of parenthood. This paper underscores the multiple biographical situations involved in the decision, in addition to the concerns about personal development and future. The current social crisis context serves as a means of justification to lessen social and family pressure. We conclude that people who have made this decision promote a different meaning from that of reproduction as a mechanism of the social order.     

Being Under Pressure to Sext: Adolescents' Experiences,Reactions, and Counter-Strategies

This study explored adolescents' experiences of being under pressure to sext (sending nude images), offering insights into what situations adolescents view as pressuring, how adolescents react to the pressure, and what counter-strategies they use. Written statements from 225 adolescents (age 13–16 years, M = 14.4 years, SD = 0.93) were analyzed using thematic analysis. Results indicated a range of situations including both explicit and implicit pressure. The pressure elicited different emotional responses, including severe physical and psychological reactions, becoming distressed, and being seemingly unconcerned. A majority of the adolescents reported successful strategies on how to ward off the unwanted sexual requests. This study provides insight into how young people cope with potentially harmful situations online.     

Variations in horizontal and vertical individualism-collectivism in four regions of Mexico / Variaciones en el individualismo-colectivismo horizontal y vertical en cuatro regiones de México

Cultures can be analysed through cultural syndromes (shared patterns of beliefs, attitudes, norms, roles and values organized around a theme). One of these syndromes, individualism-collectivism, distinguishes collectivist cultures, which prioritize collective over individual interests, from individualist cultures, which value individual autonomy, achievement and freedom. These dimensions intersect with the horizontal-vertical syndrome, where verticality means the preference for a society organized by hierarchies, in contrast to a horizontal culture, which privileges equality. This paper explores these dimensions using a new instrument in a sample of 990 participants from four regions in Mexico. The results of exploratory and confirmatory factorial analyses show four theoretically congruent factors with adequate levels of internal consistency reaching metric equivalence criteria in three of the four samples. The scores show greater support for horizontal individualism and less support for vertical collectivism. These results are discussed within the context of a cultural shift towards individualism.     

New sign language new(S): the globalization of sign language in the smartphone era

Languages are dynamic and change over the years. Changes in sign languages have been usually initiated to accommodate the needs of the local Deaf community. With the increase in smartphone use, sign languages are influenced not only by the local Deaf community, but also by foreign Deaf people on the other side of the screen, regardless of their location. Smartphones influence the sign language itself and the Deaf community by connecting different communities of Deaf people through messages, shared information and experiences, and news delivery. The popularity of this technology among Deaf communities is a social phenomenon emerging from Deaf people themselves. Smartphones may promote the globalization of sign language, shortening distances between Deaf communities around the world.     

Analysis of the workload of bank tellers of a Brazilian public institution

During the last decades there have been many changes in the banking sector organization. It has been also observed the mutual growing of musculoskeletal and mental disorders. This study investigated the workload of bank tellers at a Brazilian public institution. It was performed the Ergonomic Work Analysis (EWA). Three employees participated in this study. During the analysis process, three research instruments were applied: Inventory of Work and Risk of Illness, Yoshitake Fatigue Questionnaire and Nordic Musculoskeletal Questionnaire, beyond the realization of footage recordings and the self-confrontation. The results indicated the existence of an excess of workload on the evaluated workstations, mainly in relation to mental order constraints, that overlaps the physical aspects. Thereby it was found that the employees tend to adopt strategies trying to reduce the impacts of the excess of workload, in order to regulate it.     

Musculoskeletal disorders and psychosocial risk factors among workers of the aircraft maintenance industry

During the recent decades Brazil has experienced an exponential growth in the aviation sector resulting in an increasing workforce. The aircraft maintenance industry stands out, where the workers have to handle different kind of objects. The aim of this study was to evaluate psychosocial indicators as well as musculoskeletal symptoms and disorders among aircraft maintenance workers. One hundred and one employees were evaluated (32.69 ± 8.25 yr, 79.8 ± 13.4 kg, and 1.75 ± 0.07 m). Musculoskeletal symptoms and disorders were assessed through the Nordic Musculoskeletal Questionnaire (NMQ) and a standardized physical examination. The Job Content Questionnaire (JCQ) and the Utrecht Work Engagement Scale (UWES) were applied to evaluate psychosocial indicators. Results of the NMQ indicate the lower back as the most affected body region. On the other hand, the physical examination has shown clinical diagnosis of shoulder disorders. Neck, upper back and ankle/foot were also reported as painful sites. Most of workers have active work-demand profile and high work engagement levels. We suggest that musculoskeletal symptoms may be related to high biomechanical demand of the tasks performed by workers, what must be further investigated.     

Intermediary objects in the workspace design process: means of experience transfer in the offshore sector

The aim of this paper is to discuss the use of intermediary objects in the workspace design process of offshore accommodations module. The integration of ergonomics in the design process can lead to better work conditions, more effectiveness in the work process and less health and safety issues. Moreover, it is more efficient in terms of cost if ergonomics is considered from the initial phases of the project, as the potential costs of the redesign, the possible losses and the down-time in the operation of the platform would be more increased. The goal, then, is to discuss the integration of ergonomics and users involvement in the design process of accommodations modules, focusing on the transfer of information from reference situations by the use of intermediary objects during the process. In this paper we will present two tools developed to be used as intermediary object(s) aiming at transferring the experience from the use to the design in the specific field of offshore accommodations module.