52 research outputs found
SUSY GUT Model Building
I discuss an evolution of SUSY GUT model building, starting with the
construction of 4d GUTs, to orbifold GUTs and finally to orbifold GUTs within
the heterotic string. This evolution is an attempt to obtain realistic string
models, perhaps relevant for the LHC. This review is in memory of the sudden
loss of Julius Wess, a leader in the field, who will be sorely missed.Comment: 24 pages, 14 figures, lectures given at PiTP 2008, Institute for
Advanced Study, Princeton, to be published in the European Physical Journal
A realistic pattern of fermion masses from a five-dimensional SO(10) model
We provide a unified description of fermion masses and mixing angles in the
framework of a supersymmetric grand unified SO(10) model with anarchic Yukawa
couplings of order unity. The space-time is five dimensional and the extra flat
spatial dimension is compactified on the orbifold ,
leading to Pati-Salam gauge symmetry on the boundary where Yukawa interactions
are localised. The gauge symmetry breaking is completed by means of a rather
economic scalar sector, avoiding the doublet-triplet splitting problem. The
matter fields live in the bulk and their massless modes get exponential
profiles, which naturally explain the mass hierarchy of the different fermion
generations. Quarks and leptons properties are naturally reproduced by a
mechanism, first proposed by Kitano and Li, that lifts the SO(10) degeneracy of
bulk masses in terms of a single parameter. The model provides a realistic
pattern of fermion masses and mixing angles for large values of . It
favours normally ordered neutrino mass spectrum with the lightest neutrino mass
below 0.01 eV and no preference for leptonic CP violating phases. The right
handed neutrino mass spectrum is very hierarchical and does not allow for
thermal leptogenesis. We analyse several variants of the basic framework and
find that the results concerning the fermion spectrum are remarkably stable.Comment: 30 pages, 7 figures, 4 table
Searching for the Standard Model in the String Landscape : SUSY GUTs
The goal of the present review article is to describe the ingredients
necessary to find the Standard Model in the string landscape.Comment: 70 pages, 20 figures, this review article will be published in
Reports on Progress in Physic
Unification and Phenomenology of F-Theory GUTs with U(1)_PQ
We undertake a phenomenological study of SU(5) F-theory GUT models with an
additional U(1)_{PQ} symmetry. In such models, breaking SU(5) with hypercharge
flux leads to the presence of non-GUT multiplets in the spectrum. We study the
effect these have on the unification of gauge couplings, including two-loop
running as well as low- and high-scale threshold corrections. We use the
requirement of unification to constrain the size of thresholds from KK modes of
SU(5) gauge and matter fields. Assuming the non-GUT multiplets play the role of
messengers of gauge mediation leads to controlled non-universalities in the
sparticle spectrum while maintaining grand unification, and we study the LHC
phenomenology of this scenario. We find that the MSSM spectrum may become
compressed or stretched out {by up to a factor of three} depending on the
distribution of hypercharge flux. We present a set of benchmark points whose
production cross-sections and decays we investigate, and argue that precision
kinematic edge measurements will allow the LHC to distinguish between our model
and mGMSB.Comment: 46 pages, 15 figure
The evaluation of the fibromyalgia patients.
Fibromyalgia (FM) is a rheumatic disease characterized by musculoskeletal pain, chronic diffuse tension and/or stiffness in joints and muscles, easy fatigue, sleep and emotional disturbances, and pressure pain sensitivity in at least 11 of 18 tender points. At present, there are no instrumental tests or specific diagnostic markers for FM; in fact, many of the existing indicators are significant for research purposes only. Many differential diagnoses may be excluded by an extensive clinical examination and patient history. Considering overlap of FM with other medical conditions, the treating physicians should be vigilant: chest-X-rays and abdominal ultrasonography are the first steps of general evaluation for all the patients with suspected FM. Functional neuroimaging methods have revealed a large number of supraspinal effects in FM, a disorder mediated by mechanisms that are essentially unknown. Many treatments are used in FM patients, but evaluating their therapeutic effects in FM is difficult because the syndrome is so multifaceted. To address the identification of core outcome domains, the Initiative on IMMPACT and OMERACT workshop convened a meeting to develop consensus recommendations for chronic pain clinical trials
Transdiagnostic subgroups of cognitive impairment in early affective and psychotic illness
Abstract: Cognitively impaired and spared patient subgroups were identified in psychosis and depression, and in clinical high-risk for psychosis (CHR). Studies suggest differences in underlying brain structural and functional characteristics. It is unclear whether cognitive subgroups are transdiagnostic phenomena in early stages of psychotic and affective disorder which can be validated on the neural level. Patients with recent-onset psychosis (ROP; N = 140; female = 54), recent-onset depression (ROD; N = 130; female = 73), CHR (N = 128; female = 61) and healthy controls (HC; N = 270; female = 165) were recruited through the multi-site study PRONIA. The transdiagnostic sample and individual study groups were clustered into subgroups based on their performance in eight cognitive domains and characterized by gray matter volume (sMRI) and resting-state functional connectivity (rsFC) using support vector machine (SVM) classification. We identified an impaired subgroup (N ROP = 79, N ROD = 30, N CHR = 37) showing cognitive impairment in executive functioning, working memory, processing speed and verbal learning (all p < 0.001). A spared subgroup (N ROP = 61, N ROD = 100, N CHR = 91) performed comparable to HC. Single-disease subgroups indicated that cognitive impairment is stronger pronounced in impaired ROP compared to impaired ROD and CHR. Subgroups in ROP and ROD showed specific symptom- and functioning-patterns. rsFC showed superior accuracy compared to sMRI in differentiating transdiagnostic subgroups from HC (BACimpaired = 58.5%; BACspared = 61.7%, both: p < 0.01). Cognitive findings were validated in the PRONIA replication sample (N = 409). Individual cognitive subgroups in ROP, ROD and CHR are more informative than transdiagnostic subgroups as they map onto individual cognitive impairment and specific functioning- and symptom-patterns which show limited overlap in sMRI and rsFC. Clinical trial registry name: German Clinical Trials Register (DRKS). Clinical trial registry URL: https://www.drks.de/drks_web/ . Clinical trial registry number: DRKS00005042
Association between age of cannabis initiation and gray matter covariance networks in recent onset psychosis
Cannabis use during adolescence is associated with an increased risk of developing psychosis. According to a current hypothesis, this results from detrimental effects of early cannabis use on brain maturation during this vulnerable period. However, studies investigating the interaction between early cannabis use and brain structural alterations hitherto reported inconclusive findings. We investigated effects of age of cannabis initiation on psychosis using data from the multicentric Personalized Prognostic Tools for Early Psychosis Management (PRONIA) and the Cannabis Induced Psychosis (CIP) studies, yielding a total sample of 102 clinically-relevant cannabis users with recent onset psychosis. GM covariance underlies shared maturational processes. Therefore, we performed source-based morphometry analysis with spatial constraints on structural brain networks showing significant alterations in schizophrenia in a previous multisite study, thus testing associations of these networks with the age of cannabis initiation and with confounding factors. Earlier cannabis initiation was associated with more severe positive symptoms in our cohort. Greater gray matter volume (GMV) in the previously identified cerebellar schizophrenia-related network had a significant association with early cannabis use, independent of several possibly confounding factors. Moreover, GMV in the cerebellar network was associated with lower volume in another network previously associated with schizophrenia, comprising the insula, superior temporal, and inferior frontal gyrus. These findings are in line with previous investigations in healthy cannabis users, and suggest that early initiation of cannabis perturbs the developmental trajectory of certain structural brain networks in a manner imparting risk for psychosis later in life
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