79 research outputs found
Dynamical SUSY Breaking in Meta-Stable Vacua
Dynamical supersymmetry breaking in a long-lived meta-stable vacuum is a
phenomenologically viable possibility. This relatively unexplored avenue leads
to many new models of dynamical supersymmetry breaking. Here, we present a
surprisingly simple class of models with meta-stable dynamical supersymmetry
breaking: N=1 supersymmetric QCD, with massive flavors. Though these theories
are strongly coupled, we definitively demonstrate the existence of meta-stable
vacua by using the free-magnetic dual. Model building challenges, such as large
flavor symmetries and the absence of an R-symmetry, are easily accommodated in
these theories. Their simplicity also suggests that broken supersymmetry is
generic in supersymmetric field theory and in the landscape of string vacua.Comment: 48 pages, 1 figure, added discussion about the spectrum and some
cosmological implication
Navigation Improves Tumor Ablation Performance: Results From a Novel Liver Tumor Simulator Study
Background The efficacy of microwave ablation in treating hepatic tumors requires advanced ultrasound skills. Failure of proper technique has the potential for either under- or over-treatment and possible harm to the patient. Emprint SX? navigation provides surgeons with intra-operative, real-time navigation through augmented reality localization of the ablation antenna and the expected ablation zone. We hypothesize that incorporating this technology leads to improved targeting and optimizes ablation coverage. This study utilizes a simulated model to evaluate ablation outcomes using Emprint SX? navigation vs standard ultrasound. Methods Surgical residents and faculty were recruited from a single institution. Using a novel tumor ablation simulator, participants performed ablations via 2 modes: standard ultrasound guidance (STD) and Emprint SX? navigation (NAV). Primary outcome was the percentage of under-ablation. Secondary outcomes included percentage of over-ablation, time to complete trial, and number of attempts to position antenna. Results 281 trials were performed by fifteen participants, with 47% female and 60% novice ablationists. Under-ablation volume decreased by a mean of 16.3% (SEM ±12.9, P < .001) with NAV compared to STD. Over-ablation volume decreased by a mean of 14.0% (±8.2, P < .001). NAV time was faster by a mean of 32 seconds (±24.9, P < .001) and involved fewer antenna placement attempts by a mean of 1.3 (±1.0, P < .001). For novice ablationists, all outcomes were improved with NAV and novices saw larger improvements compared to experienced ablationists (P = .018). Discussion In a simulated model, NAV improves ablation efficacy and efficiency, with novices gaining the greatest benefit over standard ultrasound
States and transitions in black-hole binaries
With the availability of the large database of black-hole transients from the
Rossi X-Ray Timing Explorer, the observed phenomenology has become very
complex. The original classification of the properties of these systems in a
series of static states sorted by mass accretion rate proved not to be able to
encompass the new picture. I outline here a summary of the current situation
and show that a coherent picture emerges when simple properties such as X-ray
spectral hardness and fractional variability are considered. In particular,
fast transition in the properties of the fast time variability appear to be
crucial to describe the evolution of black-hole transients. Based on this
picture, I present a state-classification which takes into account the observed
transitions. I show that, in addition to transients systems, other black-hole
binaries and Active Galactic Nuclei can be interpreted within this framework.
The association between these states and the physics of the accretion flow
around black holes will be possible only through modeling of the full time
evolution of galactic transient systems.Comment: 30 pages, 11 figures, To appear in Belloni, T. (ed.): The Jet
Paradigm - From Microquasars to Quasars, Lect. Notes Phys. 794 (2009
Active Galactic Nuclei at the Crossroads of Astrophysics
Over the last five decades, AGN studies have produced a number of spectacular
examples of synergies and multifaceted approaches in astrophysics. The field of
AGN research now spans the entire spectral range and covers more than twelve
orders of magnitude in the spatial and temporal domains. The next generation of
astrophysical facilities will open up new possibilities for AGN studies,
especially in the areas of high-resolution and high-fidelity imaging and
spectroscopy of nuclear regions in the X-ray, optical, and radio bands. These
studies will address in detail a number of critical issues in AGN research such
as processes in the immediate vicinity of supermassive black holes, physical
conditions of broad-line and narrow-line regions, formation and evolution of
accretion disks and relativistic outflows, and the connection between nuclear
activity and galaxy evolution.Comment: 16 pages, 5 figures; review contribution; "Exploring the Cosmic
Frontier: Astrophysical Instruments for the 21st Century", ESO Astrophysical
Symposia Serie
1000 Genomes-based metaanalysis identifies 10 novel loci for kidney function
HapMap imputed genome-wide association studies (GWAS) have revealed >50 loci at which common variants with minor allele frequency >5% are associated with kidney function. GWAS using more complete reference sets for imputation, such as those from The 1000 Genomes project, promise to identify novel loci that have been missed by previous efforts. To investigate the value of such a more complete variant catalog, we conducted a GWAS meta-Analysis of kidney function based on the estimated glomerular filtration rate (EGFR) in 110,517 European ancestry participants using 1000 Genomes imputed data. We identified 10 novel loci with p-value < 5 Ă— 10-8 previously missed by HapMap-based GWAS. Six of these loci (HOXD8, ARL15, PIK3R1, EYA4, ASTN2, and EPB41L3) are tagged by common SNPs unique to the 1000 Genomes reference panel. Using pathway analysis, we identified 39 significant (FDR < 0.05) genes and 127 significantly (FDR < 0.05) enriched gene sets, wh
Neuroimaging-based classification of PTSD using data-driven computational approaches: a multisite big data study from the ENIGMA-PGC PTSD consortium
Background: Recent advances in data-driven computational approaches have been helpful in devising tools to objectively diagnose psychiatric disorders. However, current machine learning studies limited to small homogeneous samples, different methodologies, and different imaging collection protocols, limit the ability to directly compare and generalize their results. Here we aimed to classify individuals with PTSD versus controls and assess the generalizability using a large heterogeneous brain datasets from the ENIGMA-PGC PTSD Working group. Methods: We analyzed brain MRI data from 3,477 structural-MRI; 2,495 resting state-fMRI; and 1,952 diffusion-MRI. First, we identified the brain features that best distinguish individuals with PTSD from controls using traditional machine learning methods. Second, we assessed the utility of the denoising variational autoencoder (DVAE) and evaluated its classification performance. Third, we assessed the generalizability and reproducibility of both models using leave-one-site-out cross-validation procedure for each modality. Results: We found lower performance in classifying PTSD vs. controls with data from over 20 sites (60 % test AUC for s-MRI, 59 % for rs-fMRI and 56 % for D-MRI), as compared to other studies run on single-site data. The performance increased when classifying PTSD from HC without trauma history in each modality (75 % AUC). The classification performance remained intact when applying the DVAE framework, which reduced the number of features. Finally, we found that the DVAE framework achieved better generalization to unseen datasets compared with the traditional machine learning frameworks, albeit performance was slightly above chance. Conclusion: These results have the potential to provide a baseline classification performance for PTSD when using large scale neuroimaging datasets. Our findings show that the control group used can heavily affect classification performance. The DVAE framework provided better generalizability for the multi-site data. This may be more significant in clinical practice since the neuroimaging-based diagnostic DVAE classification models are much less site-specific, rendering them more generalizable.Stress-related psychiatric disorders across the life spa
Genome-wide association meta-analyses and fine-mapping elucidate pathways influencing albuminuria
Increased levels of the urinary albumin-to-creatinine ratio (UACR) are associated with higher risk of kidney disease progression and cardiovascular events, but underlying mechanisms are incompletely understood. Here, we conduct trans-ethnic (n = 564,257) and European-ancestry specific meta-analyses of genome-wide association studies of UACR, including ancestry- and diabetes-specific analyses, and identify 68 UACR-associated loci. Genetic correlation analyses and risk score associations in an independent electronic medical records database (n = 192,868) reveal connections with proteinuria, hyperlipidemia, gout, and hypertension. Fine-mapping and trans-Omics analyses with gene expression in 47 tissues and plasma protein levels implicate genes potentially operating through differential expression in kidney (including TGFB1, MUC1, PRKCI, and OAF), and allow coupling of UACR associations to altered plasma OAF concentrations. Knockdown of OAF and PRKCI orthologs in Drosophila nephrocytes reduces albumin endocytosis. Silencing fly PRKCI further impairs slit diaphragm formation. These results generate a priority list of genes and pathways for translational research to reduce albuminuria
Serous tubal intraepithelial carcinoma upregulates markers associated with high-grade serous carcinomas including Rsf-1 (HBXAP), cyclin e and fatty acid synthase
Serous tubal intraepithelial carcinoma (STIC) has been proposed as a precursor for many pelvic high-grade serous carcinomas. Our previous analysis of the ovarian cancer genome identified several genes with oncogenic potential that are amplified and/or overexpressed in the majority of high-grade serous carcinomas. Determining whether these genes are upregulated in STICs is important in further elucidating the relationship of STICs to high-grade serous carcinomas and is fundamental in understanding the molecular pathogenesis of high-grade serous carcinomas. In this study, 37 morphologically defined STICs were obtained from 23 patients with stage IIIC/IV high-grade serous carcinomas. Both STICs and the high-grade serous carcinomas were analyzed for expression of Rsf-1 (HBXAP), cyclin E, fatty acid synthase (FASN) and mucin-4. In addition, they were examined for expression of established markers including p53, Ki-67 and p16. We found that diffuse nuclear p53 and p16 immunoreactivity was observed in 27 (75%) of 36 and 18 (55%) of 33 STICs, respectively, whereas an elevated Ki-67 labeling index ( 6510%) was detected in 29 (78%) of 37 STICs. Cyclin E nuclear staining was seen in 24 (77%) of 35 STICs, whereas normal tubal epithelial cells were all negative. Increased Rsf-1 and FASN immunoreactivity occurred in 63%, and 62% of STICs, respectively, compared with adjacent normal-appearing tubal epithelium. Interestingly, only one STIC showed increased mucin-4 immunoreactivity. Carcinomas, when compared with STICs, overexpressed p16, Rsf-1, cyclin E and FASN in a higher proportion of cases. In conclusion, STICs express several markers including Rsf-1, cyclin E and FASN in high-grade serous carcinomas. In contrast, mucin-4 immunoreactivity either did not change or was reduced in most STICs. These results suggest that overexpression of Rsf-1, cyclin E and FASN occurs early in tumor progression
Ovarian Brenner tumour : a morphologic and immunohistochemical analysis suggesting an origin from fallopian tube epithelium
Background Brenner tumours (BTs), like other epithelial ovarian tumours, are thought to develop from the ovarian surface epithelium. Aim and Methods We hypothesised that BTs arise from transitional metaplasia near the tuboperitoneal junction which, when embedded in the ovary as Walthard cell nests, may progress to BTs. The aim of this study was to validate this hypothesis by a morphologic and immunohistochemical (IHC) analysis. Results The IHC analysis revealed that fallopian tube secretory cells, transitional metaplasia, Walthard cell nests and the epithelial component of BTs shared a similar IHC profile, consistently expressing AKR1C3 (an enzyme involved in androgen biosynthesis) and androgen receptor, but not calretinin. The tumour stromal cells that immediately surrounded the epithelial nests showed strong expression of calretinin, inhibin and steroidogenic factor 1 (markers of steroidogenic cells) in the majority of BTs. Using a highly sensitive immunofluorescent staining method, we detected small groups of cilia in transitional metaplasia and Walthard cell nests, multifocal stretches of cilia and/or ciliated vacuoles in benign BTs and well-developed cilia in atypical proliferative BTs. Conclusions Our findings suggest a tubal origin of BTs through transitional metaplasia and Walthard cell nests, based on their anatomic proximity, similar IHC profile and the presence of cilia. In addition, we hypothesise a role of androgenic stimulation in the pathogenesis of BT, based on the IHC staining pattern of calretinin, inhibin and steroidogenic factor 1 expressed in the luteinised stromal cells surrounding the epithelial nests of the tumours, and AKR1C3 and androgen receptor expressed in both the epithelial and stromal components
DYNAMIC STUDIES OF DEFORMATION AND FRACTURE AT GRAIN BOUNDARIES
The interactions of dislocations with grain boundaries in Ni, Ni3Al, alpha-Ti and Ni-S, are being studied by the technique of in-situ TEM deformation. Under certain conditions, grain boundaries act as effective barriers to dislocation motion, resulting in incorporation of glide dislocations into the grain boundary without slip generation in the adjacent grain. The mechanism of stress relief at the boundary depends on the boundary microchemistry and the test conditions. Stress relief may occur by the nucleation and propagation of a crack along the boundary or by the sudden, massive generation of dislocations into the adjacent grain : the dislocation sources are in and adjacent to the grain boundary
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