1,910 research outputs found
A Neutrinophilic 2HDM as a UV Completion for the Inverse Seesaw Mechanism
In Neutrinophilic Two Higgs Doublet Models, Dirac neutrino masses are
obtained by forbidding a Majorana mass term for the right-handed neutrinos via
a symmetry. We study a variation of such models in which that symmetry is taken
to be a local U(1), leading naturally to the typical Lagrangian of the inverse
seesaw scenario. The presence of a new gauge boson and of an extended scalar
sector result in a rich phenomenology, including modifications to Z, Higgs and
kaon decays as well as to electroweak precision parameters, and a pseudoscalar
associated to the breaking of lepton number.Comment: 21 pages, 2 figures, matches the published version in JHE
Stability effects on results of diffusion tensor imaging analysis by reduction of the number of gradient directions due to motion artifacts: an application to presymptomatic Huntington's disease.
In diffusion tensor imaging (DTI), an improvement in the signal-to-noise ratio (SNR) of the fractional anisotropy (FA) maps can be obtained when the number of recorded gradient directions (GD) is increased. Vice versa, elimination of motion-corrupted or noisy GD leads to a more accurate characterization of the diffusion tensor. We previously suggest a slice-wise method for artifact detection in FA maps. This current study applies this approach to a cohort of 18 premanifest Huntington's disease (pHD) subjects and 23 controls. By 2-D voxelwise statistical comparison of original FA-maps and FA-maps with a reduced number of GD, the effect of eliminating GD that were affected by motion was demonstrated.We present an evaluation metric that allows to test if the computed FA-maps (with a reduced number of GD) still reflect a "true" FA-map, as defined by simulations in the control sample. Furthermore, we investigated if omitting data volumes affected by motion in the pHD cohort could lead to an increased SNR in the resulting FA-maps.A high agreement between original FA maps (with all GD) and corrected FA maps (i.e. without GD corrupted by motion) were observed even for numbers of eliminated GD up to 13. Even in one data set in which 46 GD had to be eliminated, the results showed a moderate agreement
On the Viability of Minimal Neutrinophilic Two-Higgs-Doublet Models
We study the constraints that electroweak precision data can impose, after
the discovery of the Higgs boson by the LHC, on neutrinophilic
two-Higgs-doublet models which comprise one extra doublet
and a new symmetry, namely a spontaneously broken or a softly
broken global . In these models the extra Higgs doublet, via its very
small vacuum expectation value, is the sole responsible for neutrino masses. We
find that the model with a symmetry is basically ruled out by
electroweak precision data, even if the model is slightly extended to include
extra right-handed neutrinos, due to the presence of a very light scalar. While
the other model is still perfectly viable, the parameter space is considerably
constrained by current data, specially by the parameter. In particular, the
new charged and neutral scalars must have very similar masses.Comment: 22 pages, 3 figures, references and comments added, conclusions
unchanged, matches version to appear in JHE
George Huntington: a legacy of inquiry, empathy and hope
On the centenary of George Huntington's death, Wexler et.al. reconsider the setting and the collaborative effort that produced his description of “hereditary chorea,” today Huntington's disease. Tracing the changing identity of this illness, they discuss the legacy of eugenics, the search for the gene, and ongoing research toward a cure
Simultaneous conduction and valence band quantisation in ultra-shallow, high density doping profiles in semiconductors
We demonstrate simultaneous quantisation of conduction band (CB) and valence
band (VB) states in silicon using ultra-shallow, high density, phosphorus
doping profiles (so-called Si:P -layers). We show that, in addition to
the well known quantisation of CB states within the dopant plane, the
confinement of VB-derived states between the sub-surface P dopant layer and the
Si surface gives rise to a simultaneous quantisation of VB states in this
narrow region. We also show that the VB quantisation can be explained using a
simple particle-in-a-box model, and that the number and energy separation of
the quantised VB states depend on the depth of the P dopant layer beneath the
Si surface. Since the quantised CB states do not show a strong dependence on
the dopant depth (but rather on the dopant density), it is straightforward to
exhibit control over the properties of the quantised CB and VB states
independently of each other by choosing the dopant density and depth
accordingly, thus offering new possibilities for engineering quantum matter.Comment: 5 pages, 2 figures and supplementary materia
Infection of the fishes with Ligula intestinalis and Bothriocephalus acheilognathi in Sattarkhan Dam, northwestern Iran
After an extensive fish mortality in Sattarkhan Dam, in East-Azarbaijan province during the year 2002, we collected 160 specimens of the fish Alburnus filippi and 5 specimens of the fish and Alburnoides bipunctatus to examine the cause of mortality. The samples measured biometrically an examined them for internal and external infections. We found that of the 160 specimens of Alburnus filippi, 131 (81.8%) were infected with Ligula intestinalis and 26 (16.25%) specimens were infected with Bothriocephalus acheilognathi. Of 5 specimens of Alburnoides bipunctatus, 4 (80%) were infected with Ligula intestinalis and no Bothriocephalus acheilognathi observed. This is the first report of the Ligula and Bothriocephalus parasites infecting fishes in the Sattarkhan Dam
Ground states of Heisenberg spin clusters from a cluster-based projected Hartree-Fock approach
Recent work on approximating ground states of Heisenberg spin clusters by
projected Hartree-Fock theory (PHF) is extended to a cluster-based ansatz
(cPHF). Whereas PHF variationally optimizes a site-spin product state for the
restoration of spin- and point-group symmetry, cPHF groups sites into discrete
clusters and uses a cluster-product state as the broken-symmetry reference.
Intracluster correlation is thus already included at the mean-field level and
intercluster correlation is introduced through symmetry projection. Variants of
cPHF differing in the broken and restored symmetries are evaluated for ground
states and singlet-triplet gaps of antiferromagnetic spin rings for various
cluster sizes, where cPHF in general affords a significant improvement over
ordinary PHF, although the division into clusters lowers the cyclical symmetry.
On the other hand, certain two- or three-dimensional spin arrangements permit
cluster groupings compatible with the full spatial symmetry. We accordingly
demonstrate that cPHF yields approximate ground states with correct spin and
point-group quantum numbers for honeycomb lattice fragments and symmetric
polyhedra.Comment: 41 page
Evaluating the miR-302b and miR-145 expression in formalin-fixed paraffin-embedded samples of esophageal squamous cell carcinoma
Background: MicroRNAs are involved in key cellular processes regulating, and their misregulation is linked to cancer. The miR-302-367 cluster is exclusively expressed in embryonic stem and carcinoma cells. This cluster also promotes cell reprogramming and stemness process. In contrast, miR-145 is mostly regarded as a tumor suppressor, where it regulates cellular functions such as cell division, differentiation, and apoptosis. By suppressing the main pluripotency factors (OCT4, SOX2, MYC and KLF4), miR-145 silences the self-renewal program in ESCs. Therefore, the main aim of this study is to find a potential link between the expression level of hsa-miR-302b and hsa-miR-145 with tumor vs. non-tumor as well as high-grade vs. low-grade states of the esophageal tissue samples. Methods: A total number of 40 formalin-fixed, paraffin-embedded (FFPE) samples of esophageal squamous-cell carcinoma (ESCC) were obtained, and the tumor and marginal non-tumor areas delineated and punched off by an expert pathologist. Total RNA was extracted with Trizol, and cDNA synthesized using the miRCURY LNA™ Universal RT microRNA PCR Kit. Real-time reverse transcription polymerase chain reaction (RT-PCR) assays were performed using specific LNA-primers and SYBR Green master mix. Results: The expression level of miR-302b failed to show any significant difference, neither between tumor and their non-tumor counterparts, nor among tumors with different grades of malignancies (P > 0.05). In contrast, miR-145 was significantly down regulated in all grades of tumor samples (P 0.05). CONCLUSION: Our data revealed a significant down-regulation of miR-145 in ESCC tissue samples. Based on our ROC curve analysis data (AUC = 0.74, P < 0.001) miR-145 could be regarded as a potential tumor marker for diagnosis of esophageal cancer. © 2015, Academy of Medical Sciences of I.R. Iran. All rights reserved
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