Neutron Star Models in Alternative Theories of Gravity

We study the structure of neutron stars in a broad class of alternative theories of gravity. In particular, we focus on Scalar-Tensor theories and f(R) theories of gravity. We construct static and slowly rotating numerical star models for a set of equations of state, including a polytropic model and more realistic equations of state motivated by nuclear physics. Observable quantities such as masses, radii, etc are calculated for a set of parameters of the theories. Specifically for Scalar-Tensor theories, we also calculate the sensitivities of the mass and moment of inertia of the models to variations in the asymptotic value of the scalar field at infinity. These quantities enter post-Newtonian equations of motion and gravitational waveforms of two body systems that are used for gravitational-wave parameter estimation, in order to test these theories against observations. The construction of numerical models of neutron stars in f(R) theories of gravity has been difficult in the past. Using a new formalism by Jaime, Patino and Salgado we were able to construct models with high interior pressure, namely pc \u3e ρ c/3, both for constant density models and models with a polytropic equation of state. Thus, we have shown that earlier objections to f(R) theories on the basis of the inability to construct viable neutron star models are unfounded

Modeling the Release of River Ice Jams and their Impact on River Bed Scouring.

The Great Lakes are the largest fresh water reservoir on the planet. Lakes Huron and Michigan drain into Lake Erie through the Huron Erie Corridor. The average water level in Lake Huron has been dropping. The results of hydrodynamic model simulations imply that there has been an increase in the conveyance of St. Clair River that took place in the 1980’s. 1984 was marked by a massive ice jam. The jam had a duration of 24 days and its release was accompanied by high flow velocities. It is speculated that the high water flow velocities following the release of the jam caused scouring of the river bed, that lead to an increase in conveyance. A model is developed to simulate changing river bed morphology, and is combined with a hydrodynamic model in order to simulate scouring during the release of an ice jam. The model consists of modeling the river bed morphology, finding the sediment fluxes on the bed, and updating the bed morphology when scouring occurs. The hydrodynamic model uses a step-wise approximation for the bed morphology. A geometric scheme is developed to compute the local angle of inclination. The bed elevation is updated by numerically solving the Exner equation by using a finite volume approach. A new methodology is developed in order to adapt the grid to the changing bed morphology. The ice jam is modeled as an initially stationary body of water. Water is allowed to flow freely under the body. The body of water is released in the flow, accelerating and causing flow velocities over the entire river to rise rapidly. It is found that an ice jam similar to the 1984 ice jam will cause scouring of the river bed.PHDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/99841/1/mihalis_1.pd

Leiomyosarcoma of the Prostate: Case Report and Review of 54 Previously Published Cases

Prostate leiomyosarcoma is an extremely rare and highly aggressive neoplasm that accounts for less than 0.1% of primary prostate malignancies. We present a patient with primary leiomyosarcoma of the prostate and review 54 cases reported in the literature to discuss the clinical, diagnostic and therapeutic aspects of this uncommon tumor. Median survival was estimated at 17 months (95% C.I. 20.7–43.7 months) and the 1-, 3-, and 5-year actuarial survival rates were 68%, 34%, and 26%, respectively. The only factors predictive of long-term survival were negative surgical margins and absence of metastatic disease at presentation. A multidisciplinary approach is necessary for appropriate management of this dire entity

Ki67 Antigen as a Predictive Factor for Prognosis of Sinonasal Mucosal Melanoma

ObjectivesSinonasal mucosal melanoma is a rare and aggressive disease. The aim of this study was to analyze the clinical features of patients with sinonasal mucosal melanoma and to determine the role of Ki67 antigen as a predictor of prognosis in sinonasal mucosal melanoma.MethodsThis was a retrospective case-series study at a single institution, an academic tertiary referral center. From 1995 to 2007, 27 patients with sinonasal mucosal melanoma were reviewed retrospectively, and the expression of Ki67 antigen was assessed by immunohistochemistry.ResultsThe overall 5-yr survival rate was 33.9%. No significant differences were observed in 5-yr survival according to age, sex, stage, or the presence of melanin. The rates of local failure, regional failure, and distant failure were 37.0%, 14.8%, and 11.1%, respectively. Patients with spindle or mixed cell types had better prognoses than those with other cell types. At a cut-off value of 35%, patients with lower Ki67 scores showed better survival than those with higher Ki67 scores.ConclusionThe presence of spindle or mixed cell types may indicate a better prognosis than other cell types. Ki67 immunostaining may be a useful predictor of prognosis in patients with mucosal malignant melanoma of the sinonasal tract

Choroidal melanoma metastasizing to maxillofacial bones

BACKGROUND: Melanomas are malignant neoplasm of melanocytic origin, commonly seen on skin and various mucous membranes. Melanomas are the commonest intraocular malignant tumour in the adults. CASE PRESENTATION: A 50-year-old female presented with complains of painless progressive swelling in right cheek region of two months duration. Examination revealed a 6 × 4 cm bony hard swelling in right zygomatic region near and below lateral canthus of right eye with loss of vision. Investigations revealed it to be a choroidal melanoma metastatising to the zygomatic bone. Patient was successfully treated by surgery. CONCLUSION: Choroidal melanoma, which commonly metastasizes to liver and lungs, never involves the lymph nodes and metastasis to facial bones is rare. Here we report a case of choroidal melanoma metastasizing to maxillofacial bones

Noncutaneous malignant melanoma: a prognostic model from a retrospective multicenter study

Abstract Background We performed multicenter study to define clinical characteristics of noncutaneous melanomas and to establish prognostic factors patients who received curative resection. Methods Of the 141 patients who were diagnosed of non-cutaneous melanoma at 4 institutions in Korea between June 1992 and May 2005, 129 (91.5%) satisfied the selection criteria. Results Of the 129 noncutaneous melanoma patients, 14 patients had ocular melanoma and 115 patients had mucosal melanoma. For mucosal melanoma, anorectum was the most common anatomic site (n = 39, 30.2%) which was followed by nasal cavity (n = 30, 23.3%), genitourinary (n = 21, 16.3%), oral cavity (n = 14, 10.9%), upper gastrointestinal tract (n = 6, 4.7%) and maxillary sinus (n = 5, 3.9%) in the order of frequency. With the median 64.5 (range 4.3-213.0) months follow-up, the median overall survival were 24.4 months (95% CI 13.2-35.5) for all patients, and 34.6 (95% CI 24.5-44.7) months for curatively resected mucosal melanoma patients. Adverse prognostic factors of survival for 87 curatively resected mucosal melanoma patients were complete resection (R1 resection margin), and age > 50 years. For 14 ocular melanoma, Survival outcome was much better than mucosal melanoma with 73.3% of 2 year OS and 51.2 months of median OS (P = .04). Conclusion Prognosis differed according to primary sites of noncutaneous melanoma. Based on our study, noncutaneous melanoma patients should be treated differently to improve survival outcome.Peer Reviewe

Defaced land: Reading the marks of a social obsession

Street networks commonly serve some form of human habitation. That’s why the image of a dense pattern of driveways leading to vacant plots in a natural landscape seems absurd. Usually the outcome of a suspended residential development, this image has the uncanny quality of a misplaced fragment. In many coastal areas of Greece the hillsides are marked with such enigmatic patterns. Large tracts of land ranging from 50 to 500 hectares are lined with road systems of absent or rudimentary settlements. They are the unfinished projects of the numerous construction cooperatives (Oikodomikoi Synetairismoi) operating in the country, that aim to develop large rural properties. The Greek model of a construction cooperative is a privately financed planning method, initially established to answer housing needs through low-cost suburban developments. Eventually though, they committed themselves to satisfying an obsessive demand for second homes in the countryside. The zeal in occupying and disfiguring land, embedded so emphatically in these extensive scars, does not represent just the climax the domestic real estate market reached. It is also an expression of deeper disorders somehow linked to the calamities and disruptions that occurred in 20th century Greece