Fourth Moments and Independent Component Analysis

In independent component analysis it is assumed that the components of the observed random vector are linear combinations of latent independent random variables, and the aim is then to find an estimate for a transformation matrix back to these independent components. In the engineering literature, there are several traditional estimation procedures based on the use of fourth moments, such as FOBI (fourth order blind identification), JADE (joint approximate diagonalization of eigenmatrices), and FastICA, but the statistical properties of these estimates are not well known. In this paper various independent component functionals based on the fourth moments are discussed in detail, starting with the corresponding optimization problems, deriving the estimating equations and estimation algorithms, and finding asymptotic statistical properties of the estimates. Comparisons of the asymptotic variances of the estimates in wide independent component models show that in most cases JADE and the symmetric version of FastICA perform better than their competitors.Comment: Published at http://dx.doi.org/10.1214/15-STS520 in the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

Ensihoitohenkilöstön työssä kokema väkivalta ja siitä selviytyminen

Tämän opinnäytetyön tarkoituksena oli tutkia ensihoitajan työssä kokemaa väkivaltaa ja sitä, millaisia selviytymiskeinoja ensihoitajat käyttävät väkivaltatapausten läpikäymiseen. Lisäksi tarkoituksena oli selvittää, vaikkutavatko väkivaltatilanteet potilaan saamaan hoitoon ja miten työyhteisö käsittelee traumatisoivan väkivaltatilanteen. Lisääntyneen uutisoinnin ansiosta ensihoitajan työssä kokema väkivalta on tullut myös tavallisen kansalaisen tietoon. Tutkimusmenetelmänä käytettiin kvalitatiivista eli laadullista tutkimusta. Tutkimus toteutettiin Päijät-Hämeen sosiaali- ja terveysyhtymän (PHSOTEY) kanssa yhteistyössä kahdessa vaiheessa. Ensimmäisessä vaiheessa käytettiin hyväksi verkkoselainpohjaista Webropol-kyselyä. Webropol-kyselyn perusteella tutkimukseen valittiin neljä taustoiltaan erilaista ensihoitajaa haastateltaviksi. Toisessa vaiheessa haastattelut toteutettiin paikan päällä yksilöhaastatteluina ensihoidon toimipisteissä. Kaikki haastattelut toteutettiin teemahaastatteluina, joihin oli ennalta laadittu valmiit teemat ja kysymykset. Teemahaastatteluista saadut tulokset tukivat aikaisemmin tehtyjen kvantitatiivisten tutkimusten tuloksia väkivallan esiintyvyydestä. Tulosten perusteella ensihoitajat kokivat fyysistä tai henkistä väkivaltaa lähes jokaisessa työvuorossa. Selviytymiskeinoista suosituimmiksi koettiin työyhteisön kanssa keskusteleminen, ammattihenkilön johtama debriefing ja defusing sekä puolison tai läheisen kanssa keskustelu vaitiolovelvollisuutta kunnioittaen. Tuloksissa ilmeni myös, että väkivaltatilanteet saattoivat joissain tapauksissa vaikuttaa potilaan hoitoon siten, että joitakin toimenpiteitä saatettiin jättää tekemättä. Väkivaltatilanteet käsitellään alueella debriefing- ja defusing-menetelmää käyttäen ja tämän järjestelmän koettiin olevan toimiva. Tulokset ovat yksittäisten ensihoitajien mielipiteitä, joten tutkimuksesta saatuja tuloksia ei voida yleistää, mutta ne ovat kuitenkin suuntaa antavia. Jatkotutkimusaiheina voitaisiin tutkia väkivaltatilanteiden aiheuttamien sairaslomien määrää niin kenttätyössä kuin myös päivystyspoliklinikoilla, debriefingin käyttöä ja hyötyä ensihoito- ja päivystyspoliklinikkatyössä. Lisäksi voitaisiin toteuttaa koulutuspaketti väkivaltaisen potilaan kohtaamisesta hoitotyössä.The aim of this Bachelor’s thesis was to examine the violence experienced by paramedics on the field and also how they process and overcome the traumatic situations. It is also an aim to find out does violence have an effect to the care that the patient receives and how does the work community deal with these violent experiences. Due to increased coverage people have become more aware of the violence the paramedics face at work. This Bachelor’s thesis is conducted as a qualitative study. The study is carried out in co-operation with Päijät-Häme Social and Health Care Group. The study is implemented in two parts. In the first part the web browser based Webropol-poll was used. Based on these results four paramedics were chosen for interviews. In the second part these four paramedics were interviewed. The interviews were theme interviews and they were arranged during their work shifts. The results of the study support other quantitative studies on the prevalence of violence, which have been carried out before this study. Based on the results, the paramedics experienced either physical or mental violence almost on every shift. Paramedics used debriefing and defusing as a way to overcome these traumatic situations. Also discussion with the work community and close relative were common. It also came clear in the results that in some cases patients violent behavior effect on the care. Study also showed that paramedics feel that defusing and debriefing is a great way to overcome traumatic situations. The results are opinions of individual paramedics so the results cannot be generalized nationwide. Follow-up researches would be sick leaves caused by violent acts, the use of debriefing in emergency care and information package on a person who acts aggressively

Cost-benefit Analysis of Control Programmes of Giant Hogweeds in Finland

201

Dimension Reduction for Time Series in a Blind Source Separation Context Using R

Multivariate time series observations are increasingly common in multiple fields of science but the complex dependencies of such data often translate into intractable models with large number of parameters. An alternative is given by first reducing the dimension of the series and then modelling the resulting uncorrelated signals univariately, avoiding the need for any covariance parameters. A popular and effective framework for this is blind source separation. In this paper we review the dimension reduction tools for time series available in the R package tsBSS. These include methods for estimating the signal dimension of second-order stationary time series, dimension reduction techniques for stochastic volatility models and supervised dimension reduction tools for time series regression. Several examples are provided to illustrate the functionality of the package

A refined in vitro model to study inflammatory responses in organotypic membrane culture of postnatal rat hippocampal slices

BACKGROUND: Propagated tissue degeneration, especially during aging, has been shown to be enhanced through potentiation of innate immune responses. Neurodegenerative diseases and a wide variety of inflammatory conditions are linked together and several anti-inflammatory compounds considered as having therapeutic potential for example in Alzheimer's disease (AD). In vitro brain slice techniques have been widely used to unravel the complexity of neuroinflammation, but rarely, has the power of the model itself been reported. Our aim was to gain a more detailed insight and understanding of the behaviour of hippocampus tissue slices in serum-free, interface culture per se and after exposure to different pro- and anti-inflammatory compounds. METHODS: The responses of the slices to pro- and anti-inflammatory stimuli were monitored at various time points by measuring the leakage of lactate dehydrogenase (LDH) and the release of cytokines interleukin 6 (IL-6) and tumour necrosis factor alpha (TNF-α) and nitric oxide (NO) from the culture media. Histological methods were applied to reveal the morphological status after exposure to stimuli and during the time course of the culture period. Statistical power analysis were made with nQuery Advisor(®), version 5.0, (Statistical Solutions, Saugus, MA) computer program for Wilcoxon (Mann-Whitney) rank-sum test. RESULTS: By using the interface membrane culture technique, the hippocampal slices largely recover from the trauma caused by cutting after 4–5 days in vitro. Furthermore, the cultures remain stable and retain their responsiveness to inflammatory stimuli for at least 3 weeks. During this time period, cultures are susceptible to modification by inflammatory stimuli as assessed by quantitative biochemical assays and morphological characterizations. CONCLUSION: The present report outlines the techniques for studying immune responses using a serum-free slice culture model. Statistically powerful data under controlled culture conditions and with ethically justified use of animals can be obtained as soon as after 4–5 DIV. The model is most probably suitable also for studies of chronic inflammation

Missä on lähin ruoka? Maantieteellisiä näkökulmia saavutettavuudesta

Poster