Phenomenological Aspects of Four-neutrino Models

Neutrino physics has been an active and successful research field in recent years, especially experimentally. As a result of a series of great experimental discoveries neutrino oscillations are today a well established phenomenon indicating non-vanishing neutrino masses. If all the existing evidences of oscillation, coming from the atmospheric and the solar neutrino experiments and the laboratory experiment LSND, are described jointly, at least four neutrino flavors are needed. The fourth flavor must be sterile with respect to the Standard Model interactions since experiments show that only three neutrino flavors couple to the Z-boson. In this thesis various phenomenological aspects of sterile neutrinos have been investigated. We have studied the prospects of probing the possible leptonic CP violation in the proposed neutrino factory experiments. We make a comparison of the ordinary three-neutrino case and the four-neutrino case and show that these two cases are quite different in respect to the fake CP-violation effect caused by the matter in Earth's crust. We have also examined the bounds on neutrino masses and mixing parameters one can obtain from the future neutrinoless double beta decay experiments. Also in this study we have studied particularly a four-neutrino model taking into account the LSND evidence for neutrino oscillations. The lightness of the sterile neutrino, required by the oscillation data, is a challenging problem for theoretical model building. In the third original paper of this thesis we consider this issue. There the idea of the so-called pseudo-Dirac neutrino is revisited in the light of the recent experimental information on neutrino masses and mixing. In the introduction part of the thesis the theoretical background of the topics discussed in original publications is presented. Also some of the most important present and future neutrino experiments are described. The introduction part contains also some phenomenological considerations e.g. on different methods to study the absolute mass scale of neutrinos and to search for leptonic CP violation. Finally the present status of four-neutrino models is briefly described

Neutrinoless double beta decay in four-neutrino models

The most stringent constraint on the so-called effective electron neutrino mass from the present neutrinoless double beta decay experiments is |M_{ee}| < 0.2 eV, while the planned next generation experiment GENIUS is anticipated to reach a considerably more stringent limit |M_{ee}|< 0.001 eV. We investigate the constraints these bounds set on the neutrino masses and mixings of neutrinos in four-neutrino models where there exists a sterile neutrino along with the three ordinary neutrinos. We find that the GENIUS experiment would be sensitive to the electron neutrino masses down to the limit m_{\nu_e}\lsim 0.024 eV in such a scenario.Comment: 15 pages, 1 figur

Search for CP Violation at a Neutrino Factory in a Four-Neutrino Model

The CP violation effects in long baseline neutrino oscillations are studied in the framework of a four-neutrino model (three active neutrinos and one sterile neutrino). It is assumed that neutrino masses are devided into two nearly degenerate pairs, as indicated by the oscillation data. Approximative analytic expressions are derived for the probability differences \Delta P_{\a\b} \equiv P(\nu_\alpha \to \nu_\beta)- P(\bar\nu_\alpha \to \bar\nu_\beta) taking into account the CP violation effect of the Earth's crust. The matter effect is found to be small compared with the genuine CP violation term, in contrast with the three-neutrino model.Comment: 16 pages, latex, no figures, minor correction

Compositional Development of Bifidobacterium and Lactobacillus Microbiota Is Linked with Crying and Fussing in Early Infancy

OBJECTIVES: Our aim was to establish whether there is an interconnection between the compositional development of the gut microbiota and the amount of fussing and crying in early infancy. METHODS: Behavioral patterns of 89 infants during the 7(th) and 12(th) week of life were recorded in parental diaries. Total distress was defined as the sum of daily amounts of crying and fussing. Infants' gut microbiota profiles were investigated by several molecular assays during the first six months of life. RESULTS: The median (range) duration of total distress among the infants was 106 (0-478) minutes a day during the 7(th) and 58 (0-448) minutes a day during the 12(th) week. The proportion of Bifidobacterium counts to total bacterial counts was inversely associated with the amount of crying and fussing during the first 3 months of life (p = 0.03), although the number of Bifidobacterium breve was positively associated with total distress (p = 0.02). The frequency of Lactobacillus spp. at the age of 3 weeks was inversely associated with total infant distress during the 7(th) week of life (p = 0.02). CONCLUSIONS: Bifidobacterium and Lactobacillus appear to protect against crying and fussing. Identification of specific strains with optimal protective properties would benefit at-risk infants

Kuntamuutoksen tekijät : Espoon vanhusten palvelujen kotihoidon esimiesten muutostuki -kehittämishankkeen loppuraportti

Vanhusten palveluihin kohdistuu nyt ja tulevaisuudessa isoja haasteita, kun väestö ikääntyy ja kotihoidon tarve kasvaa. Miten tehdä palveluja tehokkaammin ja hyödyntää uutta teknologiaa palvelutapahtumien raportoinnissa? Miten esimiehet voivat tukea työntekijöitä arjen haasteissa? Miten kotihoito luo uudenlaista kumppanuutta asiakkaiden ja heidän omaistensa kanssa? Näitä muutoshaasteita tutkittiin yhdessä Espoon kotihoidon esimiesten ja työntekijöiden kanssa.1

Revisiting pseudo-Dirac neutrinos

We study the pseudo-Dirac mixing of left and right-handed neutrinos in the case where the Majorana masses M_L and M_R are small when compared with the Dirac mass, M_D. The light Majorana masses could be generated by a non-renormalizable operator reflecting effects of new physics at some high energy scale. In this context, we obtain a simple model independent closed bound for M_D. A phenomenologically consistent scenario is achieved with M_L,M_R ~ 10^{-7} eV and M_D ~ 10^{-5}-10^{-4} eV. This precludes the possibility of positive mass searches in the planned future experiments like GENIUS or in tritium decay experiments. If on the other hand, GENIUS does observe a positive signal for a Majorana mass \geq 10^{-3} eV, then with very little fine tuning of neutrino parameters, the scale of new physics could be in the TeV range, but pseudo-Dirac scenario in that case is excluded. We briefly discuss the constraints from cosmology when a fraction of the dark matter is composed of nearly degenerate neutrinos.Comment: 17 pages, no figures, references added, to be published in PL

Effect of oat β-glucan of different molecular weights on fecal bile acids, urine metabolites and pressure in the digestive tract – A human cross over trial

While the development of oat products often requires altered molecular weight (MW) of β-glucan, the resulting health implications are currently unclear. This 3-leg crossover trial (n = 14) investigated the effects of the consumption of oat bran with High, Medium and Low MW β-glucan (average > 1000, 524 and 82 kDa respectively) with 3 consequent meals on oat-derived phenolic compounds in urine (UHPLC-MS/MS), bile acids in feces (UHPLC-QTOF), gastrointestinal conditions (ingestible capsule), and perceived gut well-being. Urine excretion of ferulic acid was higher (p </p

Probiotics on Pediatric Functional Gastrointestinal Disorders

The potential association between gut microbiota perturbations and childhood functional gastrointestinal disturbances opens interesting therapeutic and preventive possibilities with probiotics. The aim of this review was to evaluate current evidence on the efficacy of probiotics for the management of pediatric functional abdominal pain disorders, functional constipation and infantile colic. Thus far, no single strain, combination of strains or synbiotics can be recommended for the management of irritable bowel syndrome, functional abdominal pain or functional constipation in children. However, Lactobacillus reuteri DSM 17938 may be considered for the management of breastfed colic infants, while data on other probiotic strains, probiotic mixtures or synbiotics are limited in infantile colic