1,550 research outputs found
Sflavor mixing map viewed from a high scale in supersymmetric SU(5)
We study flavor violation in a supersymmetric SU(5) grand unification
scenario in a model-independent way employing mass insertions. We examine how
the quark and the lepton sector observables restrict sfermion mixings. With a
low soft scalar mass, a lepton flavor violating process provides a stringent
constraint on the flavor structure of right-handed down-type squarks. In
particular, mu -> e gamma turns out to be highly susceptible to the 1-3 and 2-3
mixings thereof, due to the radiative correction from the top Yukawa coupling
to the scalar mass terms of 10. With a higher scalar mass around the optimal
value, in contrast, the quark sector inputs such as B-meson mixings and hadron
electric dipole moment, essentially determine the room for sfermion mixing. We
also discuss the recent deviation observed in B_s mixing phase, projected
sensitivity of forthcoming experiments, and ways to maintain the power of
leptonic restrictions even after incorporating a solution to fix the incorrect
quark-lepton mass relations.Comment: 40 pages, updated using phi_s from HFAG, conclusion unchange
Axionic Mirage Mediation
Although the mirage mediation is one of the most plausible mediation
mechanisms of supersymmetry breaking, it suffers from two crucial problems. One
is the \mu-/B \mu-problem and the second is the cosmological one. The former
stems from the fact that the B parameter tends to be comparable with the
gravitino mass, which is two order of magnitude larger than the other soft
masses. The latter problem is caused by the decay of the modulus whose
branching ratio into the gravitino pair is sizable. In this paper, we propose a
model of mirage mediation, in which Peccei-Quinn symmetry is incorporated. In
this axionic mirage mediation, it is shown that the PQ symmetry breaking scale
is dynamically determined around 10^{10-12} GeV due to the supersymmetry
breaking effects, and the \mu-problem can be solved naturally. Furthermore, in
our model, the lightest supersymmetric particle (LSP) is the axino, that is the
superpartner of the axion. The overabundance of the LSPs due to decays of
modulus/gravitino, which is the most serious cosmological difficulty in the
mirage mediation, can be avoided if the axino is sufficiently light. The
next-LSPs (NLSPs) produced by the gravitino decay eventually decay into the
axino LSPs, yielding the dominant component of the axinos remaining today. It
is shown that the axino with the mass of O(100) MeV is naturally realized,
which can constitute the dark matter of the Universe, with the free-streaming
length of the order of 0.1 Mpc. The saxion, the real scalar component of the
axion supermultiplet, can also be cosmologically harmless due to the dilution
of the modulus decay. The lifetime of NLSP is relatively long, but much shorter
than 1 sec., when the big-bang nucleosynthesis commences. The decay of NLSP
would provide intriguing collider signatures.Comment: reference added, typo correcte
Vascular-related NAC-domain 7 directly regulates a broad range of genes for xylem vessel differentiation
Htr2a-Expressing Cells in the Central Amygdala Control the Hierarchy between Innate and Learned Fear
SummaryFear is induced by innate and learned mechanisms involving separate pathways. Here, we used an olfactory-mediated innate-fear versus learned-fear paradigm to investigate how these pathways are integrated. Notably, prior presentation of innate-fear stimuli inhibited learned-freezing response, but not vice versa. Whole-brain mapping and pharmacological screening indicated that serotonin-2A receptor (Htr2a)-expressing cells in the central amygdala (CeA) control both innate and learned freezing, but in opposing directions. In vivo fiber photometry analyses in freely moving mice indicated that innate but not learned-fear stimuli suppressed the activity of Htr2a-expressing CeA cells. Artificial inactivation of these cells upregulated innate-freezing response and downregulated learned-freezing response. Thus, Htr2a-expressing CeA cells serve as a hierarchy generator, prioritizing innate fear over learned fear
B_s mixing phase and lepton flavor violation in supersymmetric SU(5)
We inspect consequences of the latest B_s mixing phase measurements on lepton
flavor violation in a supersymmetric SU(5) theory. The O(1) phase, preferring a
non-vanishing squark mixing, generically implies tau -> (e + mu) gamma and mu
-> e gamma. Depending on the gaugino and the scalar mass parameters as well as
tan beta, the rates turn out to be detectable or even already excessive, if the
RR mass insertion of down-type squarks is nonzero. We find that it becomes easy
to reconcile B_s mixing phase with lepton flavor violation given: gaugino to
scalar squared mass ratio around 1/12, both LL and RR insertions with decent
sizes, and low tan beta.Comment: 11 pages, updated using phi_s from HFAG, conclusion unchange
De novo CD5 Positive Diffuse Large B-cell Lymphomas with Bone Marrow Involvement in Korean
In CD5 positive (CD5+) mature B-cell lymphomas, newly recognized CD5+ diffuse large B-cell lymphoma (DLBCL) has been characterized by aggressive features. We studied twenty-five cases with CD5+ lymphomas involving bone marrow. Eleven cases were diagnosed as chronic lymphocytic leukemia, six cases were diagnosed as mantle cell lymphoma (MCL), and three cases with morphologic characteristics of MCL and without both the cyclin D1 expression and IGH/CCND1 rearrangement were unclassifiable. The remaining five cases, showing large to medium-sized lym-phoid cells with prominent nucleoli and a moderate amount of cytoplasm, were diagnosed as DLBCL. Five DLBCL cases were positive for CD5, CD20, surface immuno-globulin, but negative for CD23. Patients with CD5+ DLBCL showed a high age of onset (median, 68 yr) and two patients expired one month after the diagnosis. Since CD5+ DLBCL forms a distinct subgroup of DLBCL, a study of CD5 expression in DLBCL would be helpful to predict prognosis and to determine future therapeutic strategy. To the best of our knowledge, this is the first report on de novo CD5+ DLBCL in Koreans
Effect of Joule heating in current-driven domain wall motion
It was found that high current density needed for the current-driven domain
wall motion results in the Joule heating of the sample. The sample temperature,
when the current-driven domain wall motion occurred, was estimated by measuring
the sample resistance during the application of a pulsed-current. The sample
temperature was 750 K for the threshold current density of 6.7 x 10^11 A/m2 in
a 10 nm-thick Ni81Fe19 wire with a width of 240 nm. The temperature was raised
to 830 K for the current density of 7.5 x 10^11 A/m2, which is very close to
the Curie temperature of bulk Ni81Fe19. When the current density exceeded 7.5 x
10^11 A/m2, an appearance of a multi-domain structure in the wire was observed
by magnetic force microscopy, suggesting that the sample temperature exceeded
the Curie temperature.Comment: 13 pages, 4 figure
Primary T-cell Lymphoma of the Thyroid Associated with Hashimoto's Thyroiditis, Histologically Mimicking MALT-Lymphoma
Most of thyroid lymphomas are B-lineage, and T-cell lymphomas are rare. Here, we report a case of primary thyroid T-cell lymphoma associated with Hashimoto's thyroiditis. A 48-yr-old woman presented with incidentally found neck mass. Histologically, the resected right lobe of the thyroid was replaced by monomorphic small atypical lymphoid cells with lymphoepithelial lesion-like change, most of which were immunoreactive for CD3, CD8, βF-1, and TIA-1. Peripheral T-cell lymphoma, unspecified, was finally diagnosed after molecular study for TCR-γ gene rearrangement. This is the second case of cytotoxic T-cell lymphoma reported in the thyroid gland so far. Unique association between thyroid follicles and neoplastic lymphocytes may be characteristic feature of this type of T-cell lymphoma
Live imaging of altered period1 expression in the suprachiasmatic nuclei of Vipr2−/− mice1
Vasoactive intestinal polypeptide and its receptor, VPAC2, play important roles in the functioning of the brain’s circadian clock in the suprachiasmatic nuclei (SCN). Mice lacking VPAC2 receptors (Vipr2−/−) show altered circadian rhythms in locomotor behavior, neuronal firing rate, and clock gene expression, however, the nature of molecular oscillations in individual cells is unclear. Here, we used real-time confocal imaging of a destabilized green fluorescent protein (GFP) reporter to track the expression of the core clock gene Per1 in live SCN-containing brain slices from wild-type (WT) and Vipr2−/− mice. Rhythms in Per1-driven GFP were detected in WT and Vipr2−/− cells, though a significantly lower number and proportion of cells in Vipr2−/− slices expressed detectable rhythms. Further, Vipr2−/− cells expressed significantly lower amplitude oscillations than WT cells. Within each slice, the phases of WT cells were synchronized whereas cells in Vipr2−/− slices were poorly synchronized. Most GFP-expressing cells, from both genotypes, expressed neither vasopressin nor vasoactive intestinal polypeptide. Pharmacological blockade of VPAC2 receptors in WT SCN slices partially mimicked the Vipr2−/− phenotype. These data demonstrate that intercellular communication via the VPAC2 receptor is important for SCN neurons to sustain robust, synchronous oscillations in clock gene expression
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