64 research outputs found
More Amazon than Mafia: analysing a DDoS stresser service as organised cybercrime
The internet mafia trope has shaped our knowledge about organised crime groups online, yet the evidence is largely speculative and the logic often flawed. This paper adds to current knowledge by exploring the development, operation and demise of an online criminal group as a case study. In this article we analyse a DDoS (Distributed Denial of Service) stresser (also known as booter) which sells its services online to enable offenders to launch attacks. Using Social Network Analysis to explore the service operations and payment systems, our findings show a central business model that is similar to legitimate e-commerce websites in the way product, price and costumers are differentiated. It also illustrates that its organisation is distributed and not hierarchical and the overall income yield is comparatively low, requiring further organisational activity to make it pay. Finally, we show that the users of the service (mainly offenders) are not only a mixed group of actors, but that it is also possible to discriminate between different levels of seriousness of offending according to the particular service they purchased
Inferencias paleoecológicas a partir del análisis de microfósiles fúngicos en una turbera pleistoceno-holocena de Tierra del Fuego, Argentina
This paper presents the fungal remains recovered from the fossil peat sequence at La Correntina mire (S 54° 33´ - W 67°), located in the central part of Isla Grande de Tierra del Fuego, Argentina. Newly recognised fungal microfossils have distinctive morphological features that allow their systematic classification. Representatives of Glomeromycota (1), Ascomycota (7), mitosporic fungi (4) and three types of spores without taxonomic rank are identified and described. This study represents a contribution to the knowledge of the fossil fungal remains and provides data about their ecological implications. En este trabajo se dan a conocer los restos fĂşngicos recuperados en el perfil fĂłsil de la turbera La Correntina (S 54° 33´ - O 67°), ubicada en el centro de la Isla Grande de Tierra del Fuego, Argentina. Los microfĂłsiles fĂşngicos reconocidos presentan rasgos morfolĂłgicos distintivos que permiten ubicarlos sistemáticamente. Se identifican y describen representantes de Glomeromycota (1), Ascomycota (7), hongos mitospĂłricos (4) y tres tipos de esporas a las cuales no se les asigna rango taxonĂłmico. Este estudio representa un aporte al conocimiento de los restos fĂşngicos fĂłsiles y proporciona informaciĂłn acerca de sus implicancias ecolĂłgicas.Fil: Musotto, Lorena Laura. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico - CONICET - Bahia Blanca. Instituto GeolĂłgico del Sur; ArgentinaFil: Bianchinotti, Maria Virginia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico - CONICET - Bahia Blanca. Centro Rec.nat.renovables de Zona Semiarida(i); ArgentinaFil: Borromei, Ana Maria. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico - CONICET - Bahia Blanca. Instituto GeolĂłgico del Sur; Argentin
Effect of the Alterations in Contractility and Morphology Produced by Atrial Fibrillation on the Thrombosis Potential of the Left Atrial Appendage.
Atrial fibrillation (AF) is a common arrhythmia mainly affecting the elderly population, which can lead to serious complications such as stroke, ischaemic attack and vascular dementia. These problems are caused by thrombi which mostly originate in the left atrial appendage (LAA), a small muscular sac protruding from left atrium. The abnormal heart rhythm associated with AF results in alterations in the heart muscle contractions and in some reshaping of the cardiac chambers. This study aims to verify if and how these physiological changes can establish hemodynamic conditions in the LAA promoting thrombus formation, by means of computational fluid dynamic (CFD) analyses. In particular, sinus and fibrillation contractility was replicated by applying wall velocity/motion to models based on healthy and dilated idealized shapes of the left atrium with a common LAA morphology. The models were analyzed and compared in terms of shear strain rate (SSR) and vorticity, which are hemodynamic parameters directly associated with thrombogenicity. The study clearly indicates that the alterations in contractility and morphology associated with AF pathologies play a primary role in establishing hemodynamic conditions which promote higher incidence of ischaemic events, consistently with the clinical evidence. In particular, in the analyzed models, the impairment in contractility determined a decrease in SSR of about 50%, whilst the chamber pathological dilatation contributed to a 30% reduction, indicating increased risk of clot formation. The equivalent rigid wall model was characterized by SSR values about one order of magnitude smaller than in the contractile models, and substantially different vortical behavior, suggesting that analyses based on rigid chambers, although common in the literature, are inadequate to provide realistic results on the LAA hemodynamics
The Role of Patient-Specific Morphological Features of the Left Atrial Appendage on the Thromboembolic Risk Under Atrial Fibrillation
Background:
A large majority of thrombi causing ischemic complications under atrial fibrillation (AF) originate in the left atrial appendage (LAA), an anatomical structure departing from the left atrium, characterized by a large morphological variability between individuals. This work analyses the hemodynamics simulated for different patient-specific models of LAA by means of computational fluid–structure interaction studies, modeling the effect of the changes in contractility and shape resulting from AF.
Methods:
Three operating conditions were analyzed: sinus rhythm, acute atrial fibrillation, and chronic atrial fibrillation. These were simulated on four patient-specific LAA morphologies, each associated with one of the main morphological variants identified from the common classification: chicken wing, cactus, windsock, and cauliflower. Active contractility of the wall muscle was calibrated on the basis of clinical evaluations of the filling and emptying volumes, and boundary conditions were imposed on the fluid to replicate physiological and pathological atrial pressures, typical of the various operating conditions.
Results:
The LAA volume and shear strain rates were analyzed over time and space for the different models. Globally, under AF conditions, all models were well aligned in terms of shear strain rate values and predicted levels of risk. Regions of low shear rate, typically associated with a higher risk of a clot, appeared to be promoted by sudden bends and focused at the trabecule and the lobes. These become substantially more pronounced and extended with AF, especially under acute conditions.
Conclusion:
This work clarifies the role of active and passive contraction on the healthy hemodynamics in the LAA, analyzing the hemodynamic effect of AF that promotes clot formation. The study indicates that local LAA topological features are more directly associated with a thromboembolic risk than the global shape of the appendage, suggesting that more effective classification criteria should be identified
OptimShare: A Unified Framework for Privacy Preserving Data Sharing -- Towards the Practical Utility of Data with Privacy
Tabular data sharing serves as a common method for data exchange. However,
sharing sensitive information without adequate privacy protection can
compromise individual privacy. Thus, ensuring privacy-preserving data sharing
is crucial. Differential privacy (DP) is regarded as the gold standard in data
privacy. Despite this, current DP methods tend to generate privacy-preserving
tabular datasets that often suffer from limited practical utility due to heavy
perturbation and disregard for the tables' utility dynamics. Besides, there has
not been much research on selective attribute release, particularly in the
context of controlled partially perturbed data sharing. This has significant
implications for scenarios such as cross-agency data sharing in real-world
situations. We introduce OptimShare: a utility-focused, multi-criteria solution
designed to perturb input datasets selectively optimized for specific
real-world applications. OptimShare combines the principles of differential
privacy, fuzzy logic, and probability theory to establish an integrated tool
for privacy-preserving data sharing. Empirical assessments confirm that
OptimShare successfully strikes a balance between better data utility and
robust privacy, effectively serving various real-world problem scenarios
Palinology as a tool for the characterization of continental and marine environments of Late Quaternary in the Tierra del Fuego Archipelago
En esta contribuciĂłn se exponen los materiales estudiados, las metodologĂas de muestreo y las tĂ©cnicas de laboratorio utilizadas para el análisis palinolĂłgico de turberas y depĂłsitos marinos del ArchipiĂ©lago de Tierra del Fuego. Asimismo, se evalĂşan las limitaciones y fortalezas del análisis de indicadores biolĂłgicos (polen, esporas, microplancton de pared orgánica y hongos). Finalmente, se presentan tres casos de estudio donde se ilustra: i) el análisis de microfĂłsiles fĂşngicos como complemento para el estudio de los registros polĂnicos, ii) las relaciones entre los cambios en las comunidades vegetales y eventos climáticos, y iii) el uso del análisis polĂnico y de palinomorfos acuáticos para lacaracterizaciĂłn de los ambientes costeros a lo largo del Canal Beagle.In this contribution, we describe the studied materials, sampling methodologies and laboratory techniques used for the palynological analysis of peatbogs and marine deposits of the Tierra del Fuego Archipelago. Likewise, the limitationsand strengths of the analysis of biological indicators (pollen, spores, organic-walled microplankton and fungi) are evaluated. Finally, we present three case studies which illustrate: i) fungal microfossil analysis as a complement to the study of pollen records; ii) relationships between plant community changes and climatic events; and iii) the use of pollen and aquatic palynomorph analyses for the characterization of the coastal environments along the Beagle Channel.Fil: Musotto, Lorena Laura. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto GeolĂłgico del Sur. Universidad Nacional del Sur. Departamento de GeologĂa. Instituto GeolĂłgico del Sur; ArgentinaFil: Candel, Maria Soledad. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro Austral de Investigaciones CientĂficas; ArgentinaFil: Borromei, Ana Maria. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto GeolĂłgico del Sur. Universidad Nacional del Sur. Departamento de GeologĂa. Instituto GeolĂłgico del Sur; ArgentinaFil: Ponce, Juan Federico. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro Austral de Investigaciones CientĂficas; ArgentinaFil: Bianchinotti, Maria Virginia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentin
Holocene environmental changes in the fuegian forest and steppe, Argentina
Environmental changes were reconstructed from a multiproxy synthesis of over 30 localities from the Isla Grande de Tierra del Fuego and Isla de los Estados, southernmost South America. At a local scale, the results from the mountain forest and gently undulating steppe areas were integrated as well as those from the marine environments of the Beagle Channel and the Atlantic coasts. At a regional scale, the results were integrated with those published for the southernmost Andean and Extra-Andean Patagonia and the Antarctic Peninsula. This study focuses on the environmental evolution during the Late Glacial-Holocene transition, the Middle to Late Holocenetransgressive-regressive hemicycle and wet-dry oscillations, the Medieval Climate Anomaly, the Little Ice Age, the tephra inputs from the Patagonian Andes, and the recent climatic warming. Most paleoenvironmental changes are related to variations in the latitudinal position and intensity of the Southern Westerly Winds (SWW) while others are associated with astronomical or endogenous forcings. At a strong intensity of the SWW, a greater contribution of humidity to the forest areas and an increase in the rainfall gradient create windy and arid conditions in the steppe. At a weak intensity of the SWW, lower humidity input in the forest areas and the advection of air masses from the Atlantic Ocean promoted humid and slightly windy conditions in the steppe.Similar environmental trends are observed between terrestrial and marine environments in the center and south of Tierra del Fuego, Isla de los Estados and the Antarctic Peninsula, and between the Fuegian steppe and Extra- Andean Patagonia. The paleoclimatic evidence reveal high environmental variability in the last 10,000 years for this sector of the Southern HemisphereFil: Coronato, Andrea Maria Josefa. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro Austral de Investigaciones CientĂficas; ArgentinaFil: Borromei, Ana MarĂa. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro Austral de Investigaciones CientĂficas; ArgentinaFil: Ponce, Juan Federico. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro Austral de Investigaciones CientĂficas; ArgentinaFil: Candel, Soledad. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro Austral de Investigaciones CientĂficas; ArgentinaFil: Musotto, Lorena Laura. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro Austral de Investigaciones CientĂficas; ArgentinaFil: Fernández, MarilĂ©n. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro Austral de Investigaciones CientĂficas; ArgentinaFil: Laprida, Cecilia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias GeolĂłgicas; ArgentinaFil: Mehl, Adriana Ester. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Patagonia Confluencia; ArgentinaFil: Montes, Alejandro. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro Austral de Investigaciones CientĂficas; ArgentinaFil: San MartĂn, Cristina Natalia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro Austral de Investigaciones CientĂficas; ArgentinaFil: Savoretti, MarĂa Adolfina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro Austral de Investigaciones CientĂficas; ArgentinaFil: Cusminsky, Gabriela Catalina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Gordillo, Sandra. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Orgeira, Maria Julia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: LĂłpez, Ramiro. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro Austral de Investigaciones CientĂficas; ArgentinaFil: Alli, Pamela Daniela. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro Austral de Investigaciones CientĂficas; ArgentinaFil: Quiroga, Diego. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro Austral de Investigaciones CientĂficas; Argentin
"Insediamenti sostenibili della tradizione mediterranea" Il recupero dei saperi e delle conoscenze locali nei processi di pianificazione e progettazione contemporanea
Il progetto di ricerca si è posto come obiettivo lo studio degli insediamenti del Mediterraneo o delle regioni aride e semi-aride, che si sono distinti in passato per la gestione equilibrata del territorio e delle risorse, e per l’utilizzo del patrimonio dei saperi e delle conoscenze locali per ottenere “nicchie vitali autosostenibili”.
Rientrano nell’ambito di questi insediamenti le oasi. Non si tratta, infatti, di insediamenti sorti spontaneamente, come doni benevoli della Natura, ma di insediamenti artificialmente creati dalla forza e dalla coesione sociale del gruppo umano, sottraendo terreni fertili alle zone aride, mettendo in pratica le conoscenze accumulate e condividendo le fatiche per l’approvvigionamento e la gestione comune delle risorse. Il modello oasiano è specifico delle zone aride del deserto, ma può essere riferito a tutte quelle situazioni in cui l’equilibrio tra lo sfruttamento delle risorse e loro disponibilità è stato raggiunto.
Studiare il funzionamento del sistema oasi potrebbe oggi rivelarsi di grande importanza. Nella sua dimensione di ecosistema chiuso ed equilibrato convergono molteplici dinamiche e relazioni che ci consentono di capire, attuando un passaggio di scala, la sua riproducibilità in una più estesa dimensione urbana. In Italia, molti insediamenti presentano queste caratteristiche tali da potersi definire “oasi sostenibili della tradizione mediterranea”. Rientrano in questa categoria i Sassi di Matera, ma anche molti insediamenti del territorio siciliano come quelli rupestri di Sperlinga e Scicli o quelli appartenenti al paesaggio rurale della tradizione, come i dammusi di Pantelleria, le case eoliane e le masserie. Una trattazione particolarmente approfondita è riservata, a tal proposito, allo studio della Palermo normanna, dei sollazzi e dei sistemi di approvvigionamento idrico e di irrigazione di origine islamica, con i quali si stabilirà un naturale confronto.
In Sicilia, la ricchezza di esempi di architetture o di insediamenti rurali della tradizione mediterranea e di influenza islamica, l’uso di tecniche costruttive per la ventilazione e il raffrescamento naturali e di sistemi per il recupero e la conservazione dell’acqua piovana, nonché dei sistemi di approvvigionamento idrico e di corretta gestione del paesaggio e delle risorse, costituiscono un terreno valido per lo studio e l’approfondimento di modelli costruttivi e insediativi che rispondono alle caratteristiche climatiche e ambientali mediterranee.
Lo studio della scienza locale, sviluppatasi nell’ambito del Mediterraneo e delle zone aride, si inserisce nel dibattito culturale attuale sulla sostenibilità ambientale e sullo sviluppo di modelli responsabili per la progettazione architettonica e la pianificazione urbana e territoriale. In opposizione al prevalere di soluzioni costruttive sviluppate essenzialmente dai paesi del Nord Europa, che non sempre si adattano alle varianti socio-culturali e climatiche di queste regioni.
Occorre, quindi, approfondire la conoscenza delle soluzioni tecnico-costruttive e urbanistiche sviluppate in questi contesti, in cui le condizioni sfavorevoli e la scarsa disponibilità delle risorse hanno determinato l’adozione di strategie sostenibili, economiche e di grande efficacia, sia per costruire le città e abitazioni, sia per creare condizioni di fertilità dei suoli e di disponibilità idrica in zone notoriamente caratterizzate da siccità e assenza di corpi idrici superficiali, specialmente in quelle desertiche.
Partendo da queste esperienze, si è quindi cercato di delineare un quadro generale e di effettuare una valutazione critica sui modelli diffusi, evidenziando filoni culturali diversi, alcuni dei quali tendono a circoscrivere il concetto di sostenibilità al solo contesto ambientale, mentre altri tendono ad ampliare questo concetto sul piano sociale, politico, economico e culturale.
Il progetto non ha la pretesa di suggerire delle linee guida pre-confezionate, ma percorrendo dalle origini sino ai giorni nostri l’evoluzione e le caratteristiche insediative maturate in contesti ostili, e analizzando i vari approcci che le diverse scuole di pensiero propongono, indurre a delle riflessioni sugli effetti che determinate azioni possono avere sul territorio. Spesso, infatti, le conseguenze di scelte non opportunamente valutate e verificate contribuiscono non solo ad incrinare l’equilibrio ambientale, ma anche il sistema degli aspetti che definiscono l’identità culturale di un luogo e la struttura organizzativa - economica, politica, sociale - di un insediamento umano
Nothing like the mafia: cybercriminals are much like the everyday, poorly paid business worker
The role of patient specific morphology and contractility of the left atrial appendage on the thromboembolic risk in atrial fibrillation
The vast majority of thrombi that cause ischemic complications in atrial fibrillation originate in the left atrial appendage. The left atrial appendage is an anatomical structure that starts from the left atrium, characterized by a wide morphological variability between individuals. This work analyses simulated hemodynamic for different patient-specific models of the left atrial appendage, using computational fluid-structure interaction studies, modelling the effect of changes in contractility and shape resulting from atrial fibrillation.
Three operating conditions were analysed: sinus rhythm, acute atrial fibrillation, and chronic atrial fibrillation. These were simulated on four patient-specific left atrial appendage morphologies, each associated with one of the major morphological variants identified by the common classification: chicken wing, cactus, windsock, and cauliflower.
The active contractility of the wall muscle was calibrated on the basis of clinical assessments of the filling and emptying volumes and boundary conditions were imposed on the fluid to replicate physiological and pathological atrial pressures, typical of the different operating conditions.
The volume of the left atrial appendage and the shear strain rates were analysed over time and space for the different models.
Globally, under conditions of atrial fibrillation, all models were found to be well aligned in terms of shear rate values and expected risk level.
Regions of low shear velocity, typically associated with an increased risk of clot, appeared to be promoted by sudden turns and focused on the trabeculae and lobes. These become substantially more pronounced and extensive with atrial fibrillation, especially in acute conditions.
This work clarifies the role of active and passive contraction on healthy hemodynamic in the left atrial appendage, analysing the changes produced by atrial fibrillation that produce hemodynamic conditions that promote clot formation.
The study indicates that the local topological features of the left atrial appendage are more directly associated with the onset of risk than the global form of the appendage, suggesting that more effective classification criteria should be identified
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