Loss Function Based Ranking in Two-Stage, Hierarchical Models

Several authors have studied the performance of optimal, squared error loss (SEL) estimated ranks. Though these are effective, in many applications interest focuses on identifying the relatively good (e.g., in the upper 10%) or relatively poor performers. We construct loss functions that address this goal and evaluate candidate rank estimates, some of which optimize specific loss functions. We study performance for a fully parametric hierarchical model with a Gaussian prior and Gaussian sampling distributions, evaluating performance for several loss functions. Results show that though SEL-optimal ranks and percentiles do not specifically focus on classifying with respect to a percentile cut point, they perform very well over a broad range of loss functions. We compare inferences produced by the candidate estimates using data from The Community Tracking Study

Ranking USRDS Provider-Specific SMRs from 1998-2001

Provider profiling (ranking, league tables ) is prevalent in health services research. Similarly, comparing educational institutions and identifying differentially expressed genes depend on ranking. Effective ranking procedures must be structured by a hierarchical (Bayesian) model and guided by a ranking-specific loss function, however even optimal methods can perform poorly and estimates must be accompanied by uncertainty assessments. We use the 1998-2001 Standardized Mortality Ratio (SMR) data from United States Renal Data System (USRDS) as a platform to identify issues and approaches. Our analyses extend Liu et al. (2004) by combining evidence over multiple years via an AR(1) model; by considering estimates that minimize errors in classifying providers above or below a percentile cutpoint in addition to those that minimize rank-based, squared-error loss; by considering ranks based on the posterior probability that a provider\u27s SMR exceeds a threshold; by comparing these ranks to those produced by ranking MLEs and ranking P-values associated with testing whether a provider\u27s SMR = 1; by comparing results for a parametric and a non-parametric prior; by reporting on a suite of uncertainty measures. Results show that MLE-based and hypothesis test based ranks are far from optimal, that uncertainty measures effectively calibrate performance; that in the USRDS context ranks based on single-year data perform poorly, but that performance improves substantially when using the AR(1) model; that ranks based on posterior probabilities of exceeding a properly chosen SMR threshold are essentially identical to those produced by minimizing classification loss. These findings highlight areas requiring additional research and the need to educate stakeholders on the uses and abuses of ranks; on their proper role in science and policy; on the absolute necessity of accompanying estimated ranks with uncertainty assessments and ensuring that these uncertainties influence decisions

Influence of the Fermi Surface Morphology on the Magnetic Field-Driven Vortex Lattice Structure Transitions in YBa2_{2}Cu3_{3}O7−δ:δ=_{7-\delta}:\delta=0, 0.15

We report small-angle neutron scattering measurements of the vortex lattice (VL) structure in single crystals of the lightly underdoped cuprate superconductor YBa2Cu3O6.85. At 2 K, and for fields of up to 16 T applied parallel to the crystal c-axis, we observe a sequence of field-driven and first-order transitions between different VL structures. By rotating the field away from the c-axis, we observe each structure transition to shift to either higher or lower field dependent on whether the field is rotated towards the [100] or [010] direction. We use this latter observation to argue that the Fermi surface morphology must play a key role in the mechanisms that drive the VL structure transitions. Furthermore, we show this interpretation is compatible with analogous results obtained previously on lightly overdoped YBa2Cu3O7. In that material, it has long-been suggested that the high field VL structure transition is driven by the nodal gap anisotropy. In contrast, the results and discussion presented here bring into question the role, if any, of a nodal gap anisotropy on the VL structure transitions in both YBa2Cu3O6.85 and YBa2Cu3O7

Radicular cysts review

Radicular cyst is a pathologic cavity partially or completely lined by epithelium in an area of apical periodontitis that is the result of root canal infection of a tooth. The radicular cysts are presumably formed by inflammatory proliferation of epithelial cell rests of Malassez in the inflamed periapical tissues. Although several theories have been proposed as possible causes of cyst formation, the exact mechanism is still not clear. The prevalence of radicular cysts ranges from 15 to 20 % of all endodontic periapical osteolytic lesions. Histologically, radicular cysts can be categorized into pocket and true cyst. The radicular cyst appears as an osteolytic periapical radiolucent lesion around the apex of an endodontically involved tooth on conventional radiography and cone beam computed tomography. It is impossible to diagnose a radicular cyst clinically. The definitive diagnosis of a radicular cyst can only be made through histological examination of biopsy specimens. Therefore, all cyst-like periapical lesions associated with endodontically involved teeth should be initially treated with non-surgical root canal therapy. Because radicular cysts are caused by root canal infection, it is believed that pocket type of radicular cyst can be treated by conventional root canal therapy, however true type of radicular cysts may have to be managed surgically. Recurrence of radicular cysts is rare unless the root canal infection of a tooth persists because radicular cysts are not self sustaining lesion such as developmental or neoplastic cysts. The prognosis of radicular cysts is favorable after endodontic treatment

How Bulk Sensitive is Hard X-ray Photoelectron Spectroscopy: Accounting for the Cathode-Electrolyte Interface when Addressing Oxygen Redox.

Sensitivity to the "bulk" oxygen core orbital makes hard X-ray photoelectron spectroscopy (HAXPES) an appealing technique for studying oxygen redox candidates. Various studies have reported an additional O 1s peak (530-531 eV) at high voltages, which has been considered a direct signature of the bulk oxygen redox process. Here, we find the emergence of a 530.4 eV O 1s HAXPES peak for three model cathodes-Li2MnO3, Li-rich NMC, and NMC 442-that shows no clear link to oxygen redox. Instead, the 530.4 eV peak for these three systems is attributed to transition metal reduction and electrolyte decomposition in the near-surface region. Claims of oxygen redox relying on photoelectron spectroscopy must explicitly account for the surface sensitivity of this technique and the extent of the cathode degradation layer

X-ray absorption and optical spectroscopy studies of (Mg1−x_{1-x}Alx_x)B2_2

X-ray absorption spectroscopy and optical reflectance measurements have been carried out to elucidate the evolution of the electronic structure in (Mg$_{1-x}$Al$_{x}$)B$_{2}$ for \emph{x} = 0.0,0.1, 0.2, 0.3, and 0.4. The important role of B 2\emph{p} $\sigma$ hole states to superconductivity has been identified, and the decrease in the hole carrier number is \emph{quantitatively} determined. The rate of the decrease in the hole concentration agree well with the theoretical calculations. On the other hand,while the evolution of the electronic structure is gradual through the doping range, $T_c$ suppression is most significant at \emph{x} = 0.4. These results suggest that the superstructure in (Mg$_{1-x}$Al$_{x}$)B$_{2}$, in addition to the $\sigma$ holes, can affect the lattice dynamics and contributes to the $T_c$ suppression effect. Other possible explanations like the topological change of the $\sigma$ band Fermi surface are also discussed.Comment: 17 pages, 5 figures. Phys. Rev. B, in pres

Kikuchi-Fujimoto Disease: A case report and review of the literature

Kikuchi-Fujimoto Disease is a rare benign, condition of necrotising histiocytic lymphadenitis. A case of a 55 year old gentleman is described here. He presented with fevers, weight loss and tender cervical lymph nodes. Kikuchi-Fujimoto disease was diagnosed after cervical lymph node biopsy. Symptomatic treatment was provided and an uneventful full recovery was made. Of significant note, this patient's daughter had Kikuchi-Fujimoto disease almost a decade earlier. Although Kikuchi-Fujimoto disease has been reported widely, we believe this is the first familial report in the literature of a case of Kikuchi-Fujimoto disease occurring in a parent and child

Cardiac and Renal Delayed Effects of Acute Radiation Exposure: Organ Differences in Vasculopathy, Inflammation, Senescence and Oxidative Balance

We have previously shown significant pathology in the heart and kidney of murine hematopoietic-acute radiation syndrome (H-ARS) survivors of 8.7-9.0 Gy total-body irradiation (TBI). The goal of this study was to determine temporal relationships in the development of vasculopathy and the progression of renal and cardiovascular delayed effects of acute radiation exposure (DEARE) at TBI doses less than 9 Gy and to elucidate the potential roles of senescence, inflammation and oxidative stress. Our results show significant loss of endothelial cells in coronary arteries by 4 months post-TBI (8.53 or 8.72 Gy of gamma radiation). This loss precedes renal dysfunction and interstitial fibrosis and progresses to abnormalities in the arterial media and adventitia and loss of coronary arterioles. Major differences in radiation-induced pathobiology exist between the heart and kidney in terms of vasculopathy progression and also in indices of inflammation, senescence and oxidative imbalance. The results of this work suggest a need for different medical countermeasures for multiple targets in different organs and at various times after acute radiation injury to prevent the progression of DEARE