243 research outputs found

    Mammographic image restoration using maximum entropy deconvolution

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    An image restoration approach based on a Bayesian maximum entropy method (MEM) has been applied to a radiological image deconvolution problem, that of reduction of geometric blurring in magnification mammography. The aim of the work is to demonstrate an improvement in image spatial resolution in realistic noisy radiological images with no associated penalty in terms of reduction in the signal-to-noise ratio perceived by the observer. Images of the TORMAM mammographic image quality phantom were recorded using the standard magnification settings of 1.8 magnification/fine focus and also at 1.8 magnification/broad focus and 3.0 magnification/fine focus; the latter two arrangements would normally give rise to unacceptable geometric blurring. Measured point-spread functions were used in conjunction with the MEM image processing to de-blur these images. The results are presented as comparative images of phantom test features and as observer scores for the raw and processed images. Visualization of high resolution features and the total image scores for the test phantom were improved by the application of the MEM processing. It is argued that this successful demonstration of image de-blurring in noisy radiological images offers the possibility of weakening the link between focal spot size and geometric blurring in radiology, thus opening up new approaches to system optimization.Comment: 18 pages, 10 figure

    The impact of torture on mental health in the narratives of two torture survivors

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    Introduction: Torture survivors risk developing Posttraumatic Stress Disorder (PTSD) as well as other mental health problems. This clinical case study describes the impact of torture on two survivors who were treated for their PTSD with Narrative Exposure Therapy. Methods: The reports of the narratives of two torture survivors were qualitatively analyzed. It was hypothesized that torture yields overaccommodating cognitions, as well as mental defeat, which in turn, are related to severity of psychological complaints. Results: Both patients have experienced an accumulation of traumatic events. The psychological and physical torture they experienced lead to increased anticipation anxiety, loss of control and feelings of hopelessness, as well as overaccommodating cognitions regarding self and others. Conclusions: Cognitions, culture and beliefs, as well as issues of confidence and a more long-term perspective affect therapeutic work. Building trust, pacing the therapeutic process, and applying tailor-made interventions that focus on cognitions regarding self-esteem, trust in relationships, as well as safety and control are warranted

    Legacy data and cosmological constraints from the angular-size/redshift relation for ultra-compact radio sources

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    We have re-examined an ancient VLBI survey of ultra-comact radio sources at 2.29 GHz, which gave fringe amplitudes for 917 such objects with total flux density >0.5 Jy approximately. A number of cosmological investigations based upon this survey have been published in recent years. We have updated the sample with respect to both redshift and radio information, and now have full data for 613 objects, significantly larger than the number (337) used in earlier investigations. The corresponding angular-size/redshift diagram gives Omega_m=0.25+0.04/-0.03, Omega_\Lambda=0.97+0.09/-0.13 and K=0.22+0.07/-0.10. In combination with supernova data, and a simple-minded approach to CMB data based upon the angular size of the acoustic horizon, our best figures are Omega_m=0.298+0.025/-0.024, Omega_\Lambda=0.702+0.035/-0.036 and K= 0.000+0.021/-0.019. We have examined simple models of dynamical vacuum energy; the first, based upon a scalar potential V(phi)=omega_C^2 phi^2/2, gives w(0)=-1.00+0.06/-0.00, (dw/dz)_0=+0.00/-0.08; in this case conditions at z=0 require particular attention, to preclude behaviour in which phi becomes singular as z -->infinity. For fixed w limits are w=-1.20+0.15/-0.14. The above error bars are 68% confidence limits.Comment: 24 pages, 9 figure

    Cerebellopontine epidermoid presenting with trigeminal neuralgia for 10 years: a case report

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    Trigeminal neuralgia, also called tic douloureux, is a common and potentially disabling pain syndrome, which affects the trigeminal or fifth cranial nerve. The precise pathophysiology of Trigeminal neuralgia remains obscure. The disorder causes extreme, sporadic, sudden burning or shock-like face pain that lasts from few seconds to minutes and can be physically and mentally incapacitating. More than one nerve branch can be affected by the disorder. A 55-year-old female presented with pain over the left side of face for 10 years uncontrolled with carbamazepine. On examination the positive findings were reduced sensation by 25% over the left side of face with House and Brackman grade II facial nerve palsy. The corneal reflex was absent on left side. Magnetic resonance imaging showed left cerebellopontine angle (CPA) mass suggestive of an epidermoid involving the Vth nerve and Gasserian ganglion and extending into the middle cranial fossa. She underwent left suboccipital craniectomy and near total excision of the tumor with decompression of the Vth nerve which was fully engulfed by the tumor. Postoperative the VII nerve palsy increased to grade III and she had 50% loss of sensation over left side. She had no further attacks of pain and hence tapered off the carbamazepine. TN caused by cerebellopontine angle epidermoids is uncommon and should be kept in view in all cases presenting with TN. The aim of surgery for epidermoids is to decompress the cranial nerves and brain stem and not total removal with its attendant morbidity and mortality

    Diagnosis and neurosurgical treatment of glossopharyngeal neuralgia: clinical findings and 3-D visualization of neurovascular compression in 19 consecutive patients

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    Glossopharyngeal neuralgia is a rare condition with neuralgic sharp pain in the pharyngeal and auricular region. Classical glossopharyngeal neuralgia is caused by neurovascular compression at the root entry zone of the nerve. Regarding the rare occurrence of glossopharyngeal neuralgia, we report clinical data and magnetic resonance imaging (MRI) findings in a case series of 19 patients, of whom 18 underwent surgery. Two patients additionally suffered from trigeminal neuralgia and three from additional symptomatic vagal nerve compression. In all patients, ipsilateral neurovascular compression syndrome of the IX cranial nerve could be shown by high-resolution MRI and image processing, which was confirmed intraoperatively. Additional neurovascular compression of the V cranial nerve was shown in patients suffering from trigeminal neuralgia. Vagal nerve neurovascular compression could be seen in all patients during surgery. Sixteen patients were completely pain free after surgery without need of anticonvulsant treatment. As a consequence of the operation, two patients suffered from transient cerebrospinal fluid hypersecretion as a reaction to Teflon implants. One patient suffered postoperatively from deep vein thrombosis and pulmonary embolism. Six patients showed transient cranial nerve dysfunctions (difficulties in swallowing, vocal cord paresis), but all recovered within 1 week. One patient complained of a gnawing and burning pain in the cervical area. Microvascular decompression is a second-line treatment after failure of standard medical treatment with high success in glossopharyngeal neuralgia. High-resolution MRI and 3D visualization of the brainstem and accompanying vessels as well as the cranial nerves is helpful in identifying neurovascular compression before microvascular decompression procedure

    Instability, investment, disasters, and demography: natural disasters and fertility in Italy (1820–1962) and Japan (1671–1965)

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    This article examines whether natural disasters affect fertility—a topic little explored but of policy importance given relevance to policies regarding disaster insurance, foreign aid, and the environment. The identification strategy uses historic regional data to exploit natural variation within each of two countries: one European country—Italy (1820–1962), and one Asian country—Japan (1671–1965). The choice of study settings allows consideration of Jones’ (The European miracle, Cambridge University Press, Cambridge, 1981) theory that preindustrial differences in income and population between Asia and Europe resulted from the fertility response to different environmental risk profiles. According to the results, short-run instability, particularly that arising from the natural environment, appears to be associated with a decrease in fertility—thereby suggesting that environmental shocks and economic volatility are associated with a decrease in investment in the population size of future generations. The results also show that, contrary to Jones’ (The European miracle, Cambridge University Press, Cambridge, 1981) theory, differences in fertility between Italy and Japan cannot be explained away by disaster proneness alone. Research on the effects of natural disasters may enable social scientists and environmentalists alike to better predict the potential effects of the increase in natural disasters that may result from global climate change

    Visual field loss and vision-related quality of life in the Italian Primary Open Angle Glaucoma Study

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    The aim of this study was to examine the relationship between visual field (VF) loss, vision-related quality of life (QoL) and glaucoma-related symptoms in a large cohort of primary open angle glaucoma (POAG) patients. POAG patients with or without VF defects or "glaucoma suspect" patients were considered eligible. QoL was assessed using the validated versions of the 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) and glaucoma-related symptoms were assessed using the Glaucoma Symptom Scale (GSS). Patients were classified as having VF damage in one eye (VFD-1), both eyes (VFD-2), or neither eye (VFD-0). 3227 patients were enrolled and 2940 were eligible for the analysis. 13.4% of patients were classified in the VFD-0, 23.7% in the VFD-1, and 62.9% in the VFD-2 group. GSS visual symptoms domain (Func-4) and GSS non-visual symptoms domain (Symp-6) scores were similar for the VFD-0 and VFD-1 groups (p = 0.133 and p = 0.834 for Func-4 and Symp-6, respectively). VFD-0 group had higher scores than VFD-2 both in Func-4 (p < 0.001) and Symp-6 domains (p = 0.035). Regarding the NEI-VFQ-25, our data demonstrated that bilateral VF defects are associated with vision-related QoL deterioration, irrespective of visual acuity
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