Diffusion and Aggregation in an Agent Based Model of Stock Market Fluctuations

We describe a new model to simulate the dynamic interactions between market price and the decisions of two different kind of traders. They possess spatial mobility allowing to group together to form coalitions. Each coalition follows a strategy chosen from a proportional voting ``dominated'' by a leader's decision. The interplay of both kind of agents gives rise to complex price dynamics that is consistent with the main stylized facts of financial time series.Comment: 17 pages, 8 figures (accepted for publication in Int. J. Mod. Phys. C

Constraining the true nature of an exotic binary in the core of NGC 6624

We report on the identification of the optical counterpart to Star1, the exotic object serendipitously discovered by Deutsch et al. in the core of the Galactic globular cluster NGC 6624. Star1 has been classified by Deutsch et al. as either a quiescent Cataclysmic Variable or a low-mass X-ray binary. Deutsch et al. proposed StarA as possible optical counterpart to this object. We used high-resolution images obtained with the Hubble Space Telescope to perform a variability analysis of the stars close to the nominal position of Star1. While no variability was detected for StarA, we found another star, here named COM_Star1, showing a clear sinusoidal light modulation with amplitude \Delta m_F435W~0.7 mag and orbital period of P_orb~98 min. The shape of the light curve is likely caused by strong irradiation by the primary heating one hemisphere of the companion, thus suggesting a quite hot primary.Comment: Accepted for publication by ApJ Letters; 6 pages, 5 figure

TOWARDS FULLY AUTOMATED DIGITAL ALIBIS WITH SOCIAL INTERACTION

Digital traces found on local hard drives as a result of online activities have become very valuable in reconstructing events in digital forensic investigations. This paper demonstrates that forged alibis can be created for online activities and social interactions. In particular, a novel, automated framework is presented that uses social interactions to create false digital alibis. The framework simulates user activity and supports communications via email as well as instant messaging using a chatbot. The framework is evaluated by extracting forensic artifacts and comparing them with the results obtained from a human user study

Rat Race Dynamics and Crazy Companies: The Diffusion of Technologies and Social Behavior

How and why do technologies spread when and where they do? What are the implications and consequences for the structure, wealth, and management of human organizations? These expansive questions were the subject of the presentations and discussions of the International Conference on Diffusion of Technologies and Social Behavior, summarized in this chapter. The chapter is organized under the following headings: empirical regularities; theoretical issues; predictability; roles of time and space; definition of niche and innovation; selection dynamics; role of marketing; social aspects of diffusion; globalization of diffusion processes; and applications of diffusion. While the chapter treats some questions for policy in both the public and private sectors, it emphasizes research needs and opportunities in the diffusion field

Extracapsular tumor spread and the risk of local, axillary and supraclavicular recurrence in node-positive, premenopausal patients with breast cancer

BACKGROUND: Extracapsular tumor spread (ECS) has been identified as a possible risk factor for breast cancer recurrence, but controversy exists regarding its role in decision making for regional radiotherapy. This study evaluates ECS as a predictor of local, axillary, and supraclavicular recurrence. PATIENTS AND METHODS: International Breast Cancer Study Group Trial VI accrued 1475 eligible pre- and perimenopausal women with node-positive breast cancer who were randomly assigned to receive three to nine courses of classical combination chemotherapy with cyclophosphamide, methotrexate, and fluorouracil. ECS status was determined retrospectively in 933 patients based on review of pathology reports. Cumulative incidence and hazard ratios (HRs) were estimated using methods for competing risks analysis. Adjustment factors included treatment group and baseline patient and tumor characteristics. The median follow-up was 14 years. RESULTS: In univariable analysis, ECS was significantly associated with supraclavicular recurrence (HR = 1.96; 95% confidence interval 1.23-3.13; P = 0.005). HRs for local and axillary recurrence were 1.38 (P = 0.06) and 1.81 (P = 0.11), respectively. Following adjustment for number of lymph node metastases and other baseline prognostic factors, ECS was not significantly associated with any of the three recurrence types studied. CONCLUSIONS: Our results indicate that the decision for additional regional radiotherapy should not be based solely on the presence of ECS

Transport Modelling During Preparation of General Plans in Big Cities: Reasons and Challenges

Rapidly growing mobility of people in European cities attaches greater importance to the sustainable developmentconcept. The dynamics of European cities are however different. Cites such as Lithuanian, Slovakian and Polishones will rapidly increase traffic flows and car ownership at fast pace. Also in most of Western Europe, even if at lowerrates, private mobility is increasing. In some cities, however, car use and car ownership are finally decreasing, alsothanks to policies implemented. Of course, an increase of traffic flows poses problems in terms of street space, pollutionand liveability of cities. Sustainable integration of all kinds of transport into the urban development process is one ofthe most effective actions in the hands of city planners. The coordination between the planning of residential and businessdevelopment areas and the expansion of public transport and its hierarchical integration is however a difficult butnecessary exercise. Transport modelling tools, in particular, need important advancements to integrate transport andland use in simulations. This article analyses the main challenges in the use of transport models to support the constructionof city plans by means of two case studies of Milan and Vilnius. The analysis deals both with traditional aspects,such as the proper simulation of multimodal choices, the level of detail of zoning, the issues associated to the simulationof traffic management policies. Then, we will focus on two aspects still open: the integration of transport modelling andeconomic assessment or ranking of actions, and the inclusion of land use changes in the modelling

Electric structure of the Copahue Volcano (Neuquen Province, Argentina), from magnetotelluric soundings: 1D and 2D modellings

Four magnetotelluric soundings were carried out in 1993 in the region of the Copahue active volcano located at the border between Chile and Argentina (37°45'S, 71°18'W). Three soundings were located inside the caldera of the ancient stratovolcano (east of Copahue) and the fourth outside it. The soundings inside the caldera were situated at about 6, 11, and 14 km from the volcano. Digital data were obtained covering the range of periods from 1 sec to 10,000 sec using induction coils and a flux-gate magnetometer to obtain the magnetic data and Cu-SO 4Cu electrodes for electric field measurements. The apparent resistivity curves corresponding to principal directions were analyzed in conjunction with the geological background in order to eliminate distortion - which is very important in this hot volcanic region. Then, 1D modellings were performed using the 'normal' curves - i.e., curves without distortions. Using the apparent resistivity curves with distortions, 2D modelling was also performed along a profile perpendicular to the regional tectonic trend suggested by MT soundings into the caldera. Results show low resistivity values of about 3-15 Ωm between 9 km to 20 km depth in the crust, suggesting high temperatures, with minimum values of about 700°C with partially melted zones in the upper crust between 9 km to 20 km depth under the caldera. The presence of a possible sulphide-carbonaceous layer (SC layer) in the upper basement could play an important role in lowering the electrical resistivities because of its high electronic conductivity.En 1993 se realizaron cuatro sondeos magnetotelúricos en la región del volcán activo Copahue, ubicado en el lı́mite entre Chile y Argentina (37°45′ Lat. Sur, 71°18′ Long. Oeste). Tres sondeos fueron localizados dentro de la caldera del antiguo estratovolcán — al Este del volcán Copahue — y el cuarto, fuera de ella. Los sondeos dentro de la caldera fueron situados a aproximadamente 6, 11 y 14 Km del volcán Copahue. Los datos fueron obtenidos en forma digitalizada, cubriendo el rango de perı́odos desde 1 seg. a 10000 seg., usando bobinas de inducción y un magnetómetro flux-gate para obtener la información magnética. Para medir el campo eléctrico, se usaron electrodos de Cu-SO4Cu. Las curvas de resistividades aparentes correspondientes a las direcciones principales fueron analizadas tomando en cuenta el contexto geológico para eliminar, en lo posible, las distorsiones presentes en las curvas — muy importantes en esta región volcánica caliente. Luego, se realizaron modelaciones 1D usando las curvas “normales” — es decir, sin distorsiones. Además, usando las curvas de resistividad aparente distorsionadas, se efectuó una modelación 2D a lo largo de un perfil perpendicular a la tectónica regional sugerida por los sondeos MT dentro de la caldera. Los resultados muestran valores bajos de resistividad de 3Ωm a 15 Ωm entre los 9 Km y 20 Km de profundidad en la Corteza, ası́ sugiriendo altas temperaturas, con valores minimos de alrededor de 700°C, con zonas de fusión parcial en la Corteza superior entre los 9 Km y los 20 Km de profundidad bajo la caldera. La presencia de una posible capa sulfuro-carbonática (capa SC) emplazada en el sector superior del basamento podrı́a jugar un papel importante en descender las resistividades eléctricas debido a su alta conductividad electrónica.Fil: Mamani, Manuel Jesus. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Borzotta, Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Venencia, Jorge Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Maidana, A.. Comision Nacional de Actividades Espaciales; ArgentinaFil: Moyano, C.E.. Comision Nacional de Actividades Espaciales; ArgentinaFil: Castiglione, B. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentin

Immune control of HIV-1 infection after therapy interruption: immediate versus deferred antiretroviral therapy

Abstract Background The optimal stage for initiating antiretroviral therapies in HIV-1 bearing patients is still a matter of debate. Methods We present computer simulations of HIV-1 infection aimed at identifying the pro et contra of immediate as compared to deferred Highly Active Antiretroviral Therapy (HAART). Results Our simulations highlight that a prompt specific CD8+ cytotoxic T lymphocytes response is detected when therapy is delayed. Compared to very early initiation of HAART, in deferred treated patients CD8+ T cells manage to mediate the decline of viremia in a shorter time and, at interruption of therapy, the virus experiences a stronger immune pressure. We also observe, however, that the immunological effects of the therapy fade with time in both therapeutic regimens. Thus, within one year from discontinuation, viral burden recovers to the value at which it would level off in the absence of therapy. In summary, simulations show that immediate therapy does not prolong the disease-free period and does not confer a survival benefit when compared to treatment started during the chronic infection phase. Conclusion Our conclusion is that, since there is no therapy to date that guarantees life-long protection, deferral of therapy should be preferred in order to minimize the risk of adverse effects, the occurrence of drug resistances and the costs of treatment.</p

TERMAS DE SANTA TERESITA. LA RIOJA. RESULTADOS GEOFISICOS MAGNETOTELURICOS. UN CUERPO ANOMALO

Con la finalidad de estudiar la distribución de resistividades eléctricas en la corteza superior, incluyendo la cuencasedimentaria, correspondientes a la región de las Termas de Santa Teresita (La Rioja), se efectuaron seis sondeosmagnetotelúricos (SMT) a lo largo de un perfil con rumbo aproximado Este - Oeste de 20 km de extensión.Se registró el campo electromagnético natural en el rango de periodos de 0,057 seg. hasta 300 seg. Las direccionesprincipales y el caracter de las curvas de resistividades eléctricas aparentes sugieren que el alineamiento deAmbato sería condicionante de la tectónica regional. Los resultados indican resistividades de 3 - 4 Qm para lacuenca sedimentaria salina y sugieren fuertemente la presencia de una anomalía de conductividad generada porun cuerpo elongado que se ubicaría bajo el tope del basamento cristalino con resistividad eléctrica inferior a 0.1ohm m, siguiendo el mencionado alineamiento. Grafito u otros materiales con conductividad electrónica se sugierencomo parcialmente responsables de esta anomalía.Palabras Claves: Geofísica. Cuenca sedimentaria. Magnetotelúrica. Geoterrnia