Inference for a skew extension of the Grubbs model

In this paper, we discuss inferential aspects for the Grubbs model when the unknown quantity x (latent response) follows a skew-normal distribution, extending early results given in Arellano-Valle et al. (J Multivar Anal 96:265-281, 2005b). Maximum likelihood parameter estimates are computed via the EM-algorithm. Wald and likelihood ratio type statistics are used for hypothesis testing and we explain the apparent failure of the Wald statistics in detecting skewness via the profile likelihood function. The results and methods developed in this paper are illustrated with a numerical example.

Framework for Skew-Probit Links in Binary Regression

We review several asymmetrical links for binary regression models and present a unified approach for two skew-probit links proposed in the literature. Moreover, under skew-probit link, conditions for the existence of the ML estimators and the posterior distribution under improper priors are established. The framework proposed here considers two sets of latent variables which are helpful to implement the Bayesian MCMC approach. A simulation study to criteria for models comparison is conducted and two applications are made. Using different Bayesian criteria we show that, for these data sets, the skew-probit links are better than alternative links proposed in the literature.

Influence Diagnostics for a Skew Extension of the Grubbs Measurement Error Model

Influence diagnostics methods are extended in this article to the Grubbs model when the unknown quantity x (latent variable) follows a skew-normal distribution. Diagnostic measures are derived from the case-deletion approach and the local influence approach under several perturbation schemes. The observed information matrix to the postulated model and Delta matrices to the corresponding perturbed models are derived. Results obtained for one real data set are reported, illustrating the usefulness of the proposed methodology.

Predicting random effects with an expanded finite population mixed model

Prediction of random effects is an important problem with expanding applications. In the simplest context, the problem corresponds to prediction of the latent value (the mean) of a realized cluster selected via two-stage sampling. Recently, Stanek and Singer [Predicting random effects from finite population clustered samples with response error. J. Amer. Statist. Assoc. 99, 119-130] developed best linear unbiased predictors (BLUP) under a finite population mixed model that outperform BLUPs from mixed models and superpopulation models. Their setup, however, does not allow for unequally sized clusters. To overcome this drawback, we consider an expanded finite population mixed model based on a larger set of random variables that span a higher dimensional space than those typically applied to such problems. We show that BLUPs for linear combinations of the realized cluster means derived under such a model have considerably smaller mean squared error (MSE) than those obtained from mixed models, superpopulation models, and finite population mixed models. We motivate our general approach by an example developed for two-stage cluster sampling and show that it faithfully captures the stochastic aspects of sampling in the problem. We also consider simulation studies to illustrate the increased accuracy of the BLUP obtained under the expanded finite population mixed model. (C) 2007 Elsevier B.V. All rights reserved.

A robust Bayesian approach to null intercept measurement error model with application to dental data

Measurement error models often arise in epidemiological and clinical research. Usually, in this set up it is assumed that the latent variable has a normal distribution. However, the normality assumption may not be always correct. Skew-normal/independent distribution is a class of asymmetric thick-tailed distributions which includes the Skew-normal distribution as a special case. In this paper, we explore the use of skew-normal/independent distribution as a robust alternative to null intercept measurement error model under a Bayesian paradigm. We assume that the random errors and the unobserved value of the covariate (latent variable) follows jointly a skew-normal/independent distribution, providing an appealing robust alternative to the routine use of symmetric normal distribution in this type of model. Specific distributions examined include univariate and multivariate versions of the skew-normal distribution, the skew-t distributions, the skew-slash distributions and the skew contaminated normal distributions. The methods developed is illustrated using a real data set from a dental clinical trial. (C) 2008 Elsevier B.V. All rights reserved.

Alteration of purinergic P2X(4) and P2X(7) receptor expression in rats with temporal-lobe epilepsy induced by pilocarpine

Although ATP and P2X receptor activity have been lately associated with epilepsy, little is known regarding their exact roles in epileptogenesis. Temporal-lobe epilepsy (TLE) in rat was induced by pilocarpine in order to study changes of hippocampal P2X(2), P2X(4) and P2X(7) receptor expression during acute, latent or chronic phases of epilepsy. During acute and chronic phases increased P2X(7) receptor expression was principally observed in glial cells and glutamatergic nerve terminals, suggesting participation of this receptor in the activation of inflammatory and excitotoxic processes during epileptogenesis. No significant alterations of hippocampal P2X(2) and P2X(4) receptor expression was noted during the acute or latent phase when compared to the control group, indicating that these receptors are not directly involved with the initiation of epilepsy. However, the reduction of hippocampal P2X(4) receptor immunostaining in the chronic phase could reflect neuronal toss or decreased GABAergic signaling. (C) 2008 Elsevier B.V. All rights reserved.

Energy Efficiency through Thermal Energy Storage : Possibilities for the Swedish Building Stock

The need for heating and cooling in buildings constitutes a considerable part of the total energy use in a country and reducing this need is of outmost importance in order to reach national and international goals for reducing energy use and emissions. One important way of reaching these goals is to increase the proportion of renewable energy used for heating and cooling of buildings. Perhaps the largest obstacle with this is the often occurring mismatch between the availability of renewable energy and the need for heating or cooling, hindering this energy to be used directly. This is one of the problems that can be solved by using thermal energy storage (TES) in order to save the heat or cold from when it is available to when it is needed. This thesis is focusing on the combination of TES techniques and buildings to achieve increased energy efficiency for heating and cooling. Various techniques used for TES as well as the combination of TES in buildings have been investigated and summarized through an extensive literature review. A survey of the Swedish building stock was also performed in order to define building types common in Sweden. Within the scope of this thesis, the survey resulted in the selection of three building types, two single family houses and one office building, out of which the two residential buildings were used in a simulation case study of passive TES with increased thermal mass (both sensible and latent). The second case study presented in the thesis is an evaluation of an existing seasonal borehole storage of solar heat for a residential community. In this case, real measurement data was used in the evaluation and in comparisons with earlier evaluations. The literature reviews showed that using TES opens up potential for reduced energy demand and reduced peak heating and cooling loads as well as possibilities for an increased share of renewable energy to cover the energy demand. By using passive storage through increased thermal mass of a building it is also possible to reduce variations in the indoor temperature and especially reduce excess temperatures during warm periods, which could result in avoiding active cooling in a building that would otherwise need it. The analysis of the combination of TES and building types confirmed that TES has a significant potential for increased energy efficiency in buildings but also highlighted the fact that there is still much research required before some of the technologies can become commercially available. In the simulation case study it was concluded that only a small reduction in heating demand is possible with increased thermal mass, but that the time with indoor temperatures above 24 °C can be reduced by up to 20%. The case study of the borehole storage system showed that although the storage system worked as planned, heat losses in the rest of the system as well as some problems with the system operation resulted in a lower solar fraction than projected. The work presented within this thesis has shown that TES is already used successfully for many building applications (e.g. domestic hot water stores and water tanks for storing solar heat) but that there still is much potential in further use of TES. There are, however, barriers such as a need for more research for some storage technologies as well as storage materials, especially phase change material storage and thermochemical storage.

Energy Efficiency through Thermal Energy Storage - Evaluation of the Possibilities for the Swedish Building Stock, Phase 1

As a first step in assessing the potential of thermal energy storage in Swedish buildings, the current situation of the Swedish building stock and different storage methods are discussed in this paper. Overall, many buildings are from the 1960’s or earlier having a relatively high energy demand, creating opportunities for large energy savings. The major means of heating are electricity for detached houses and district heating for multi dwelling houses and premises. Cooling needs are relatively low but steadily increasing, emphasizing the need to consider energy storage for both heat and cold. The thermal mass of a building is important for passive storage of thermal energy but this has not been considered much when constructing buildings in Sweden. Instead, common ways of storing thermal energy in Swedish buildings today is in water storage tanks or in the ground using boreholes, while latent thermal energy storage is still very uncommon.

Folkmusikundervisningen på fiol och gitarr och dess historiska rötter

How folk musicians of today learn to play their instruments is an over-all question in this article. One violin lesson and one guitar lesson have been observed at Framnäs folk high school. Three research questions were formulated. What do the two lessons have in common? What are the differences? How could the folk music education of today be related to the Swedish fiddler movement in the 1920s and other folk music traditions? Theoretically, the interpretation of the results was based on the mimesis theory of Ricoeur. Two teachers and three students participated in the study. The results showed that the lessons were structured in a similar way and dominated by master apprenticeship teaching. The violin teacher showed a more respectful attitude towards the tradition compared to the guitar teacher. Great parts of the manifest ideology of the fiddler movement seems to have become concealed into a latent or frozen ideology in the formal folk music education of today. There seems to be no big differences between learning the music by way of visiting an older fiddler hundred years ago compared to the study of music today at a formal institution.

Maternal health care professionals perspective on the provision and use of antenatal and delivery care : a qualitative descriptive study in rural Vietnam

Background. High quality maternal health care is an important tool to reduce maternal and neonatal mortality. Services offered should be evidence based and adapted to the local setting. This qualitative descriptive study explored the perspectives and experiences of midwives, assistant physicians and medical doctors on the content and quality of maternal health care in rural Vietnam. Method. The study was performed in a rural district in northern Vietnam. Four focus group discussions with health care professionals at primary health care level were conducted. The data was analysed using qualitative manifest and latent content analysis. Result. Two main themes emerged: "Contextual conditions for maternal health care" and "Balancing between possibilities and constraints". Contextual conditions influenced both pregnant women's use of maternal health care and health care professionals' performance. The study participants stated that women's uses of maternal health care were influenced by economical constraints and cultural norms that impeded their autonomy in relation to childbearing. Structural constraints within the health care system included inadequate financing of the primary health care, resulting in lack of human resources, professional re-training and adequate equipment. Conclusion. Contextual conditions strongly influenced the performance and interaction between pregnant women and health care professionals within antenatal care and delivery care in a rural district of Vietnam. Although Vietnam is performing comparatively well in terms of low maternal and child mortality figures, this study revealed midwives' and other health care professionals' perceived difficulties in their daily work. It seemed maternal health care was under-resourced in terms of staff, equipment and continuing education activities. The cultural setting in Vietnam constituting a strong patriarchal society and prevailing Confucian norms limits women's autonomy and reduce their possibility to make independent decisions about their own reproductive health. This issue should be further addressed by policy-makers. Strategies to reduce inequities in maternal health care for pregnant women are needed. The quality of client-provider interaction and management of pregnancy may be strengthened by education, human resources, re-training and provision of essential equipment.

The effects of attitudes and personality traits on mode choice

We hypothesise that differences in people's attitudes and personality traits lead them to attribute varying importance to environmental considerations, safety, comfort, convenience and flexibility. Differences in personality traits call be revealed not only in the individuals' choice of transport, but also in other actions of their everyday lives-such as how much they recycle, whether they take precautions or avoid dangerous pursuits. Conditioning on a set of exogenous individual characteristics, we use indicators of attitudes and personality traits to form latent variables for inclusion in an, otherwise standard, discrete mode choice model. With a sample of Swedish commuters, we find that both attitudes towards flexibility and comfort, as well as being pro-environmentally inclined, influence the individual's choice of mode. Although modal time and cost still are important, it follows that there are other ways, apart from economic incentives, to attract individuals to the, from society's perspective, desirable public modes of transport. Our results should provide useful information to policy-makers and transportation planners developing sustainable transportation systems.

Manifesta och latenta ideologier om lärande inom svensk spelmansrörelse under 1920-talet

The purpose of this article was to illuminate existing educational ideologies in the Swedish fiddler movement (Spelmansrörelsen) 1923-1927. This period was characterized by the organization and to some extent institutionalization of Swedish folk music. Furthermore, the purpose was to discuss the results in relation to the folk music education of today. The empirical data was taken from the journal Hembygden, which was a magazine for scholars, enthusiasts and practitioners of folk music. Theoretically, the study was based on a concept of ideology developed by Sven-Eric Liedman: in every time there are two basic forms of identifiable ideology, manifest and latent. From the empirical material as a whole (around 900 articles), a selection was made to find articles dealing with aspects of learning among the fiddlers (33 articles). After content analysis the following themes were generated: Fiddlers’ repertoire, Fiddlers’ masters, Rooms for learning, Learning formation. The writers in Hembygden often emphasized the autodidactic aspects of learning and especially the importance of learning by ear. This manifest ideology of authenticity presumed that learning directly from another fiddler by playing together was to prefer to formal schooling. In spite of a tendency towards more ensemble playing, the folk music education of today in Sweden is characterized by a similar retrospective ideology as in the 1920s.

"An on-going individual adjustment" : a qualitative study of midwives' experiences counselling pregnant women on physical activity in Sweden

Background: In Sweden, midwives play prominent supportive role in antenatal care by counselling and promoting healthy lifestyles. This study aimed to explore how Swedish midwives experience the counselling of pregnant women on physical activity, specifically focusing on facilitators and barriers during pregnancy. Also, addressing whether the midwives perceive that their own lifestyle and body shape may influence the content of the counselling they provide. Methods: Eight focus group discussions (FGD) were conducted with 41 midwives working in antenatal care clinics in different parts of Sweden between September 2013 and January 2014. Purposive sampling was applied to ensure a variation in age, work experience, and geographical location. The FGD were digitally recorded, transcribed verbatim, and analyzed using manifest and latent content analysis. Results: The main theme- "An on-going individual adjustment" was built on three categories: "Counselling as a challenge"; "Counselling as walking the thin ice" and "Counselling as an opportunity" reflecting the midwives on-going need to adjust their counselling depending on each woman's specific situation. Furthermore, counselling pregnant women on physical activity was experienced as complex and ambiguous, presenting challenges as well as opportunities. When midwives challenged barriers to physical activity, they risked being rejected by the pregnant women. Despite risking rejection, the midwives tried to promote increased physical activity based on their assessment of individual needs of the pregnant woman. Some participants felt that their own lifestyle and body shape might negatively influence the counselling; however, the majority of participants did not agree with this perspective. Conclusions: Counselling on physical activity during pregnancy may be a challenging task for midwives, characterized by on-going adjustments based on a pregnant woman's individual needs. Midwives strive to find individual solutions to encourage physical activity. However, to improve their counselling, midwives may benefit from further training, also organizational and financial barriers need to be addressed. Such efforts might result in improved opportunities to further support pregnant women's motivation for performance of physical activity.

Effect of facilitation of local maternal-and-newborn stakeholder groups on neonatal mortality : cluster-randomized controlled trial

BACKGROUND: Facilitation of local women's groups may reportedly reduce neonatal mortality. It is not known whether facilitation of groups composed of local health care staff and politicians can improve perinatal outcomes. We hypothesised that facilitation of local stakeholder groups would reduce neonatal mortality (primary outcome) and improve maternal, delivery, and newborn care indicators (secondary outcomes) in Quang Ninh province, Vietnam. METHODS AND FINDINGS: In a cluster-randomized design 44 communes were allocated to intervention and 46 to control. Laywomen facilitated monthly meetings during 3 years in groups composed of health care staff and key persons in the communes. A problem-solving approach was employed. Births and neonatal deaths were monitored, and interviews were performed in households of neonatal deaths and of randomly selected surviving infants. A latent period before effect is expected in this type of intervention, but this timeframe was not pre-specified. Neonatal mortality rate (NMR) from July 2008 to June 2011 was 16.5/1,000 (195 deaths per 11,818 live births) in the intervention communes and 18.4/1,000 (194 per 10,559 live births) in control communes (adjusted odds ratio [OR] 0.96 [95% CI 0.73-1.25]). There was a significant downward time trend of NMR in intervention communes (p = 0.003) but not in control communes (p = 0.184). No significant difference in NMR was observed during the first two years (July 2008 to June 2010) while the third year (July 2010 to June 2011) had significantly lower NMR in intervention arm: adjusted OR 0.51 (95% CI 0.30-0.89). Women in intervention communes more frequently attended antenatal care (adjusted OR 2.27 [95% CI 1.07-4.8]). CONCLUSIONS: A randomized facilitation intervention with local stakeholder groups composed of primary care staff and local politicians working for three years with a perinatal problem-solving approach resulted in increased attendance to antenatal care and reduced neonatal mortality after a latent period. TRIAL REGISTRATION: Current Controlled Trials ISRCTN44599712. Please see later in the article for the Editors' Summary.

Lessons learned from stakeholders in a facilitation intervention targeting neonatal health in Quang Ninh province, Vietnam

BACKGROUND: In northern Vietnam the Neonatal health - Knowledge Into Practice (NeoKIP, Current Controlled Trials ISRCTN44599712) trial has evaluated facilitation as a knowledge translation intervention to improve neonatal survival. The results demonstrated that intervention sites, each having an assigned group including local stakeholders supported by a facilitator, lowered the neonatal mortality rate by 50% during the last intervention year compared with control sites. This process evaluation was conducted to identify and describe mechanisms of the NeoKIP intervention based on experiences of facilitators and intervention group members. METHODS: Four focus group discussions (FGDs) were conducted with all facilitators at different occasions and 12 FGDs with 6 intervention groups at 2 occasions. Fifteen FGDs were audio recorded, transcribed verbatim, translated into English, and analysed using thematic analysis. RESULTS: Four themes and 17 sub-themes emerged from the 3 FGDs with facilitators, and 5 themes and 18 sub-themes were identified from the 12 FGDs with the intervention groups mirroring the process of, and the barriers to, the intervention. Facilitators and intervention group members concurred that having groups representing various organisations was beneficial. Facilitators were considered important in assembling the groups. The facilitators functioned best if coming from the same geographical area as the groups and if they were able to come to terms with the chair of the groups. However, the facilitators' lack of health knowledge was regarded as a deficit for assisting the groups' assignments. FGD participants experienced the NeoKIP intervention to have impact on the knowledge and behaviour of both intervention group members and the general public, however, they found that the intervention was a slow and time-consuming process. Perceived facilitation barriers were lack of money, inadequate support, and the function of the intervention groups. CONCLUSIONS: This qualitative process evaluation contributes to explain the improved neonatal survival and why this occurred after a latent period in the NeoKIP project. The used knowledge translation intervention, where facilitators supported multi-stakeholder coalitions with the mandate to impact upon attitudes and behaviour in the communes, has low costs and potential for being scaled-up within existing healthcare systems.