Luminosity, Energy and Polarization Studies for the Linear Collider: Comparing e+e- and e-e- for NLC and TESLA

We present results from luminosity, energy and polarization studies at a future Linear Collider. We compare e+e- and e-e- modes of operation and consider both NLC and TESLA beam parameter specifications at a center-of-mass energy of 500 GeV. Realistic colliding beam distributions are used, which include dynamic effects of the beam transport from the Damping Rings to the Interaction Point. Beam-beam deflections scans and their impact for beam-based feedbacks are considered. A transverse kink instability is studied, including its impact on determining the luminosity-weighted center-of-mass energy. Polarimetry in the extraction line from the IP is presented, including results on beam distributions at the Compton IP and at the Compton detector.Comment: 17 pages, 12 figures. Presented at 5th International Workshop on Electron-Electron Interactions at TeV Energies, December 12-14, 2003, Santa Cruz, C

Pruebas Empíricas con Empresas que Realizan Oferta Pública de sus Acciones en los Mercados de Valores de Argentina, Chile, Brasil, México, Colombia, Perú, Venezuela, y Estados Unidos.

CAPÍTULO I INTRODUCCIÓN TEÓRICA - Introducción - Formulación del problema - Marco teórico - Introducción - Modelo CAPM -Estado actual del conocimiento - Objetivos - Objetivo general - Objetivos específicos - Hipótesis - Presupuestos aceptados - Hipótesis a verificar - Universo de análisis - Metodología - Recopilación de Datos - Cálculo de los Betas Bursátiles - Cálculo de los Betas Contables - Estudio de la significación estadística de los coeficientes betas - Determinación del grado de asociación de las variables de objeto de estudio - Análisis de significación de los coeficientes de correlación - Resultados esperados - CAPÍTULO II DETERMINACIÓN DEL GRADO DE ASOCIACIÓN ENTRE BETAS CONTABLES Y BETAS DE MERCADO DE EMPRESAS ARGENTINAS QUE REALIZAN OFERTA PÚBLICA DE SUS ACCIONES EN LA B.C.B.A. - Introducción - Universo de análisis - Descripción y características de los datos utilizados - Fundamentación del período de estudio seleccionado - Herramientas cuantitativas empleadas - Interpretación de las variables que surgen de la regresión - Determinación de la asociación entre betas contables y betas bursátiles - Análisis de significación de los coeficientes de correlación - Análisis empírico - Betas de mercado - Cartera de mercado - Cálculo de betas de mercado - Resumen de los betas bursátiles de las compañías que cotizan en la BCBA - Betas contables base ROE - Cartera de mercado estimada con datos contables - Cálculo de betas contables - Resumen de los betas contables de las compañías que cotizan en la BCBA - Betas contables base utilidad bruta Cartera de mercado estimada con datos contables - Cálculo de betas contables - Resumen de los betas contables de las compañías que cotizan en la BCBA - Análisis de correlación entre betas contables (Base ROE) y betas bursátiles - Determinación del grado de significación de la asociación entre betas contables (Base ROE) y betas de mercado - Análisis de correlación entre betas contables (Base Utilidad Bruta) y betas bursátiles - Determinación del grado de significación de la asociación entre betas contables (Base Utilidad Bruta) y betas de mercado - Resumen del capítulo II - CAPÍTULO III ESTUDIO DE BETAS SECTORIALES EXTRANJEROS ANÁLISIS EMPÍRICO CON EMPRESAS QUE REALIZAN OFERTA PÚBLICA DE SUS ACCIONES EN LA BCBA, EN LA BCS, EN EL BOVESPA, EN LA BMV, EN LA BVC (Colombia), EN LA BVL, EN LA BVC (Caracas), EN LA NASDAQ, Y EN LA NYSE - Introducción - Descripción y características de los datos utilizados - Universo de análisis - Fundamentación del período de estudio seleccionado - Herramientas cuantitativas empleadas - Determinación de la asociación entre betas sectoriales argentinos y betas sectoriales extranjeros - Análisis de significación de los coeficientes de correlación - Análisis empírico - Cálculo de betas sectoriales - Análisis de betas sectoriales apalancados - Betas sectoriales apalancados (Argentina – Chile) - Betas sectoriales apalancados (Argentina – Brasil) - Betas sectoriales apalancados (Argentina – México) - Betas sectoriales apalancados (Argentina – Colombia) - Betas sectoriales apalancados (Argentina – Perú) - Betas sectoriales apalancados (Argentina – Venezuela) - Betas sectoriales apalancados (BCBA – NASDAQ) - Betas sectoriales apalancados (BCBA – NYSE) - Análisis de betas sectoriales desapalancados - Betas sectoriales desapalancados (Argentina – Chile) - Betas sectoriales desapalancados (Argentina – Brasil) - Betas sectoriales desapalancados (Argentina – México) - Betas sectoriales desapalancados (Argentina – Colombia) - Betas sectoriales desapalancados (Argentina – Perú) - Betas sectoriales desapalancados (Argentina – Venezuela) - Betas sectoriales desapalancados (BCBA – NASDAQ) - Betas sectoriales desapalancados (BCBA – NYSE) - Análisis de significación entre betas sectoriales argentinos y extranjeros - Análisis de correlación parcial entre betas sectoriales argentinos y extranjeros - Análisis del efecto tamaño de la empresa en el rendimiento requerido al capital propio - Resumen del capítulo III - Conclusiones generales - Bibliografía - Anexo I - Anexo II - Anexo III - Anexo IVEl presente trabajo pretende determinar una metodología de trabajo para estimar el riesgo de mercado en empresas argentinas que no disponen de la cotización bursátil de sus acciones. Para ello se evalúa las distintas alternativas de cálculo a través del uso de herramientas estadísticas. Se investiga la significación estadística del grado de correlación entre los betas contables y los betas bursátiles de las compañías que realizan oferta pública de sus acciones en la Bolsa de Comercio de Buenos Aires. También se analiza la significación estadística del grado de asociación entre los betas sectoriales de Argentina, con los betas sectoriales de Chile, Brasil, Estados Unidos, México, Perú, Colombia y Venezuela.Fil: Ponzo Florimonte., Rafael M. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina

PET-Derived Radiomics and Artificial Intelligence in Breast Cancer: A Systematic Review

Breast cancer (BC) is a heterogeneous malignancy that still represents the second cause of cancer-related death among women worldwide. Due to the heterogeneity of BC, the correct identification of valuable biomarkers able to predict tumor biology and the best treatment approaches are still far from clear. Although molecular imaging with positron emission tomography/computed tomography (PET/CT) has improved the characterization of BC, these methods are not free from drawbacks. In recent years, radiomics and artificial intelligence (AI) have been playing an important role in the detection of several features normally unseen by the human eye in medical images. The present review provides a summary of the current status of radiomics and AI in different clinical settings of BC. A systematic search of PubMed, Web of Science and Scopus was conducted, including all articles published in English that explored radiomics and AI analyses of PET/CT images in BC. Several studies have demonstrated the potential role of such new features for the staging and prognosis as well as the assessment of biological characteristics. Radiomics and AI features appear to be promising in different clinical settings of BC, although larger prospective trials are needed to confirm and to standardize this evidence

PSMA PET/CT in Castration-Resistant Prostate Cancer: Myth or Reality?

Background: prostate-specific membrane antigen (PSMA) ligand PET has been recently incorporated into international guidelines for several different indications in prostate cancer (PCa) patients. However, there are still some open questions regarding the role of PSMA ligand PET in castration-resistant prostate cancer (CRPC). The aim of this work is to assess the clinical value of PSMA ligand PET/CT in patients with CRPC. Results: PSMA ligand PET has demonstrated higher detection rates in comparison to conventional imaging and allows for a significant reduction in the number of M0 CRPC patients. However, its real impact on patients’ prognosis is still an open question. Moreover, in CRPC patients, PSMA ligand PET presents some sensitivity and specificity limitations. Due to its heterogeneity, CRPC may present a mosaic of neoplastic clones, some of which could be PSMA−/FDG+, or vice versa. Likewise, unspecific bone uptake (UBU) and second primary neoplasms (SNPs) overexpressing PSMA in the neoangiogenic vessels represent potential specificity issues. Integrated multi-tracer imaging (PSMA ligand and [18F]FDG PET) together with a multidisciplinary discussion could allow for reaching the most accurate evaluation of each patient from a precision medicine point of view

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Prognostic value of exercise cardiac tomography performed late after percutaneous coronary intervention in symptomatic and symptom-free patients

The long-term prognostic value of single-photon emission computed tomography (SPECT) performed late after percutaneous coronary intervention (PCI) has not been extensively evaluated. Moreover, the role of myocardial ischemia at SPECT in symptom-free patients after PCI is not clear. This study was designed to determine the long-term prognostic value of SPECT in predicting cardiac events after PCI in symptomatic and symptom-free patients. Exercise technetium-99m sestamibi SPECT was performed in 206 patients between 12 and 18 months after PCI. All patients were followed for a mean period of 37 +/- 16 months. Cardiac death, nonfatal myocardial infarction, and late revascularization procedures were considered to be events. Myocardial ischemia at SPECT was detectable in 44 patients. During follow-up, 24 patients experienced events (cardiac death in 4 patients, myocardial infarction in 10, and late revascularization in 10). At univariate analysis, the summed stress score (p <0.05) and summed difference score (p <0.001) were significant predictors of cardiac events. Event-free survival curves showed a higher event rate in patients with than without ischemia (p <0.001). The occurrence of cardiac events was higher in the presence of ischemia at SPECT in symptomatic and symptom-free patients (both p <0.001). The results of this study demonstrate that the extent and severity of myocardial ischemia at exercise SPECT performed between 12 and 18 months after PCI predicts cardiac events during long-term follow-up in symptomatic and symptom-free patients

18F-Choline PET/CT-Positive Lytic Bone Lesions in Prostate Cancer and Accidental Myeloma Detection

ABSTRACT: F-choline PET/CT was performed for suspected prostate cancer relapse in a 67-year-old man with hip pain and a rapid rise in prostate-specific antigen values (1.1 ng/mL). PET imaging showed an area of increased F-choline bone uptake in the right ischium. Coregistered CT images showed a lytic bone lesion. The infrequent CT appearance of a possible prostate carcinoma metastasis led to additional laboratory testing that showed a monoclonal \u3b3-peak and to subsequent biopsy, which revealed a solitary plasmocytoma

Sestamibi SPECT in the detection of myocardial viability in patients with chronic ischemic left ventricular dysfunction: comparison between visual and quantitative analysis

BACKGROUND: Technetium 99m sestamibi cardiac scintigraphy is widely used as a means of predicting myocardial viability in patients with chronic ischemic left ventricular (LV) dysfunction. No data are available comparing the results of visual and quantitative analysis of tomographic imaging in the assessment of myocardial viability. The aim of this study was to directly compare visual and quantitative analysis of resting sestamibi single photon emission computed tomography in the identification of viable myocardium in patients with chronic LV dysfunction. METHODS AND RESULTS: Sixty-five patients with an earlier myocardial infarction and LV dysfunction that had occurred within 1 week underwent echocardiography and resting sestamibi SPECT. In each patient, regional tracer distribution was visually assessed and quantitatively measured in 13 segments. Regional LV function was evaluated in corresponding segments by means of echocardiography. All patients underwent revascularization, and echocardiography was repeated 12 months later as a means of assessing the recovery of regional LV function. Among all akinetic or dyskinetic revascularized segments, 66 of 112 viable segments (59%) and 85 of 100 nonviable segments (81%) were identified by means of visual analysis. Eighty-two of 112 viable segments (73%; P<.05 vs. visual analysis) and 74 of 100 nonviable segments (74%; P = .3 vs. visual analysis) were identified by means of quantitative analysis, with a threshold of 55%. Receiver operating characteristic curve areas constructed by using visual and quantitative analyses for the detection of myocardial viability in all 212 akinetic or dyskinetic segments were 0.79+/-0.04 and 0.81+/-0.03, respectively (P = not significant). Overall concordance in the detection of myocardial viability between visual and quantitative analysis was observed in 165 of akinetic or dyskinetic dysfunctional segments (78%), with a kappa value of 0.6. CONCLUSIONS: The results of this study demonstrate that, in patients with chronic myocardial infarction and LV dysfunction, visual and quantitative analysis of sestamibi tomographic images at rest have similar overall accuracy in predicting the recovery of LV function after coronary revascularization procedures