1,380 research outputs found
Gauge Threshold Corrections in Warped Geometry
We discuss the Kaluza-Klein threshold correction to low energy gauge
couplings in theories with warped extra-dimension, which might be crucial for
the gauge coupling unification when the warping is sizable. Explicit
expressions of one-loop thresholds are derived for generic 5D gauge theory on a
slice of AdS_5, where some of the bulk gauge symmetries are broken by orbifold
boundary conditions and/or by bulk Higgs vacuum values. Effects of the mass
mixing between the bulk fields with different orbifold parities are included as
such mixing is required in some class of realistic warped unification models.Comment: 33 pages, 1 figure, 6 tables, invited contribution to New Journal of
Physics Focus Issue on 'Extra Space Dimensions
The Presence of Two Distinct Red Giant Branches in the Globular Cluster NGC 1851
There is a growing body of evidence for the presence of multiple stellar
populations in some globular clusters, including NGC 1851. For most of these
peculiar globular clusters, however, the evidence for the multiple red
giant-branches (RGBs) having different heavy elemental abundances as observed
in Omega Centauri is hitherto lacking, although spreads in some lighter
elements are reported. It is therefore not clear whether they also share the
suggested dwarf galaxy origin of Omega Cen or not. Here we show from the CTIO
4m UVI photometry of the globular cluster NGC 1851 that its RGB is clearly
split into two in the U - I color. The two distinct RGB populations are also
clearly separated in the abundance of heavy elements as traced by Calcium,
suggesting that the type II supernovae enrichment is also responsible, in
addition to the pollutions of lighter elements by intermediate mass asymptotic
giant branch stars or fast-rotating massive stars. The RGB split, however, is
not shown in the V - I color, as indicated by previous observations. Our
stellar population models show that this and the presence of bimodal
horizontal-branch distribution in NGC 1851 can be naturally reproduced if the
metal-rich second generation stars are also enhanced in helium.Comment: 13 pages, 4 figures, accepted for publication in the Astrophysical
Journal Letter
Acute Chylous Peritonitis Mimicking Ovarian Torsion in a Patient with Advanced Gastric Carcinoma
The extravasation of chyle into the peritoneal space usually does not accompany an abrupt onset of abdominal pain with symptoms and signs of peritonitis. The rarity of this condition fails to reach preoperative diagnosis prior to laparotomy. Here, we introduce a case of chylous ascites that presented with acute abdominal pain mimicking peritonitis caused by ovarian torsion in a 41-yr-old female patient with advanced gastric carcinoma. An emergency exploratory laparotomy was performed but revealed no evidence of ovarian torsion. Only chylous ascites was discovered in the operative field. She underwent a complete abdominal hysterectomy and salphingo-oophorectomy. Only saline irrigation and suction-up were performed for the chylous ascites. The postoperative course was uneventful. Her bowel movement was restored within 1 week. She was allowed only a fat-free diet, and no evidence of re-occurrence of ascites was noted on clinical observation. She now remains under consideration for additional chemotherapy
Influence of B1 Inhomogeneity on Pharmacokinetic Modeling of Dynamic Contrast-Enhanced MRI: A Simulation Study
Objective: To simulate the B1-inhomogeneity-induced variation of pharmacokinetic parameters on DCE-MRI.
Materials and Methods: B1-inhomogeneity-induced flip angle (FA) variation was estimated in a phantom study. Monte Carlo simulation was performed to assess the FA-deviation-induced measurement error of the pre-contrast R1, contrast-enhancement ratio, Gd concentration, and two-compartment pharmacokinetic parameters (Ktrans, ve and vp).
Results: B1-inhomogeneity resulted in -23% ~ 5% fluctuations (95% confidence interval (CI) of % error) of FA. The 95% CIs of FA-dependent % errors in the gray matter and blood were as follows: -16.7% - 61.8% and -16.7% - 61.8% for the pre-contrast R1, -1.0% - 0.3% and -5.2% - 1.3% for the contrast-enhancement ratio, and -14.2% - 58.1% and -14.1% - 57.8% for the Gd concentration, respectively. These resulted in -43.1% - 48.4% error for Ktrans, -32.3% - 48.6% error for the ve, and -43.2% - 48.6% error for vp. The pre-contrast R1 was more vulnerable to FA error than the contrast-enhancement ratio, and was therefore a significant cause of the Gd-concentration error. For example, a -10% FA error led to a 23.6% deviation in the pre-contrast R1, -0.4% in the contrast-enhancement ratio, and 23.6% in the Gd concentration. In a simulated condition with a 3% FA error in a target lesion and a -10% FA error in a feeding vessel, the % errors of the pharmacokinetic parameters were -23.7% for Ktrans, -23.7% for ve, and -23.7% for vp.
Conclusion: Even a small degree of B1-inhomogeneity can cause a significant error in the measurement of pharmacokinetic parameters on DCE-MRI, while the vulnerability of the pre-contrast R1 calculations to FA deviations is a significant cause of the miscalculation.ope
RELATIONSHIP BETWEEN THE SEQUENTIAL MOVEMENT, MUSCLE CO-CONTRACTION AND KLNEMATLC VARIABLES OF FLYING DISC BACKHAND THROWING
The aim of this study was to analyse sequential movement of segments and co-contraction index and its correlation with kinematic variables. Disc trajectory and velocity (DV) variables calculated according to the medio-lateral (DOM) and vertical (DOV) displacement. The time differences calculated according to maximum linear velocity of segments from proximal to distal and reported as shoulder & elbow (S-E), elbow & wrist (E-W), wrist & finger (W-F). Co-contraction index (CI) were calculated for flexor and extensor carpi radialis. DV and S-E, W-F, DOM showed correlation which may be caused by the sequential movement of S-E, W-F and the displacement of the disc. Also, there was a correlation between the CI, DOM and DOV. Therefore, decrease of time gap between the segment movements and higher CI may increase the DV effectively
Corrective Septorhinoplasty in Acute Nasal Bone Fractures
Objectives Closed reduction is generally recommended for acute nasal bone fractures, and rhinoplasty is considered in cases with an unsatisfactory outcome. However, concomitant rhinoplasty with fracture reduction might achieve better surgical outcomes. This study investigated the surgical techniques and outcomes in patients who underwent rhinoplasty and fracture reduction concomitantly, during the acute stage of nasal bone fracture. Methods Forty-five patients who underwent concomitant rhinoplasty and fracture reduction were enrolled. Nasal bone fractures were classified into three major types (type I, simple fracture; type II, fracture line that mimics nasal osteotomy; and type III, comminuted fracture) based on computed tomography images and preoperative facial images. Two independent otolaryngology-head and neck surgeons evaluated the surgical outcomes and telephone based survey were made to evaluate patients satisfaction. Results Among 45 patients, there were 39 males and 6 females. Type I was the commonest type of fracture with 18 patients (40%), while the most frequently used surgical technique for corrective surgery was dorsal augmentation with 44 patients (97.8%). The mean visual analogue scale satisfaction score of the surgeons and patients were 7.62 and 8, respectively, with no significant differences between fracture types. Conclusion Concomitant rhinoplasty with fracture reduction can be performed for acute nasal bone fracture patients, and it might lead to better aesthetic outcomes
Occurrence and characterization of oseltamivir-resistant influenza virus in children between 2007-2008 and 2008-2009 seasons
PurposeThere was a global increase in the prevalence of oseltamivir-resistant influenza viruses during the 2007-2008 influenza season. This study was conducted to investigate the occurrence and characteristics of oseltamivir-resistant influenza viruses during the 2007-2008 and 2008-2009 influenza seasons among patients who were treated with oseltamivir (group A) and those that did not receive oseltamivir (group B).MethodsA prospective study was conducted on 321 pediatric patients who were hospitalized because of influenza during the 2007-2008 and 2008-2009 influenza seasons. Drug resistance tests were conducted on influenza viruses isolated from 91 patients.ResultsThere was no significant difference between the clinical characteristics of groups A and B during both seasons. Influenza A/H1N1, isolated from both groups A and B during the 2007-2008 and 2008-2009 periods, was not resistant to zanamivir. However, phenotypic analysis of the virus revealed a high oseltamivir IC50 range and that H275Y substitution of the neuraminidase (NA) gene and partial variation of the hemagglutinin (HA) gene did not affect its antigenicity to the HA vaccine even though group A had a shorter hospitalization duration and fewer lower respiratory tract complications than group B. In addition, there was no significant difference in the clinical manifestations between oseltamivir-susceptible and oseltamivir-resistant strains of influenza A/H1N1.ConclusionEstablishment of guidelines to efficiently treat influenza with oseltamivir, a commonly used drug for treating influenza in Korean pediatric patients, and a treatment strategy with a new therapeutic agent is required
Non-Functional Parathyroid Adenoma Presenting as a Massive Cervical Hematoma: A Case Report
Parathyroid adenoma usually manifests with symptoms related to hypercalcemia, such as urinary stone and bone fracture. It may also present with asymptomatic hypercalcemia. However, spontaneous cervical hematoma may occur very rarely as a result of extracapsular hemorrhage of a cervical parathyroid adenoma causing acute painful cervical swelling, bruising, dyspnea, hoarseness and dysphagia. We report a 44-year-old woman who manifested as a spontaneous cervical hematoma without any clinical evidence of hyperparathyroidism
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