56 resultados para Collapsed objects and Supernovae
Resumo:
Reading and reading habits have radically changed in the digital age. Readers are no longer physically bound to textual objects and libraries, they deal with texts by copying, altering, and annotating them, and they mix established textual forms with other semiotic systems such as pictograms, icons and images. These circumstances also provoke a renewed research interest in the history of reading. In this talk, I will concentrate on reading processes as to how they were enacted and practised in early Italian and German humanism. I will start with some paradigmatic scenes described in Petrarch’s letters (among others the famous visit of the Mont Ventoux, where Petrarch, after having enjoyed a spectacular panorama, withdraws into the contemplative reading of St-Augustine). The transmission of Petrarch’s writings in humanist circles of Southern Germany (e.g. with the Schedel and Gossembrot families in Nurnberg, Augsburg and Strasburg) will then lead to specific reading practices documented in manuscripts that once belonged to coherent libraries and are nowadays spread all over Europe. In the case of the former tradesman and mayor Sigismund Gossembrot, complex habits of textual annotating and cross-referencing can be observed. The dichotomy of the Latin terms otium (‘rest’ and ‘leisure’) and negotium (‘activity’, but also ‘practice’, ‘negotiation’, ‘circulation of social energy’ in the sense of New Historicism) will be used as an ideal-type outline to describe the occurring processes of reading.
Resumo:
Reading and reading habits have radically changed in the digital age. Readers are no longer physically bound to textual objects and libraries, they deal with texts by copying, altering, and annotating them, and they mix established textual forms with other semiotic systems such as pictograms, icons and images. These circumstances also provoke a renewed research interest in the history of reading. In this talk, I will concentrate on reading processes as to how they were enacted and practised in early Italian and German humanism. I will start with some paradigmatic scenes described in Petrarch’s letters (among others the famous visit of the Mont Ventoux, where Petrarch, after having enjoyed a spectacular panorama, withdraws into the contemplative reading of St-Augustine). The transmission of Petrarch’s writings in humanist circles of Southern Germany (e.g. with the Schedel and Gossembrot families in Nurnberg, Augsburg and Strasburg) will then lead to specific reading practices documented in manuscripts that once belonged to coherent libraries and are nowadays spread all over Europe. In the case of the former tradesman and mayor Sigismund Gossembrot, complex habits of textual annotating and cross-referencing can be observed. The dichotomy of the Latin terms otium (‘rest’ and ‘leisure’) and negotium (‘activity’, but also ‘practice’, ‘negotiation’, ‘circulation of social energy’ in the sense of New Historicism) will be used as an ideal-type outline to describe the occurring processes of reading.
Resumo:
The attention deficit/hyperactivity disorder (ADHD) shows an increased prevalence in arrested offenders compared to the normal population. The aim of the present study was to investigate whether ADHD symptoms are a major risk factor for criminal behaviour, or whether further deficits, mainly abnormalities in emotion-processing, have to be considered as important additional factors that promote delinquency in the presence of ADHD symptomatology. Event related potentials (ERPs) of 13 non-delinquent and 13 delinquent subjects with ADHD and 13 controls were compared using a modified visual Go/Nogo continuous performance task (VCPT) and a newly developed version of the visual CPT that additionally requires emotional evaluation (ECPT). ERPs were analyzed regarding their topographies and Global Field Power (GFP). Offenders with ADHD differed from non-delinquent subjects with ADHD in the ERPs representing higher-order visual processing of objects and faces (N170) and facial affect (P200), and in late monitoring and evaluative functions (LPC) of behavioural response inhibition. Concerning neural activity thought to reflect the allocation of neural resources and cognitive processing capability (P300 Go), response inhibition (P300 Nogo), and attention/expectancy (CNV), deviances were observable in both ADHD groups and may thus be attributed to ADHD rather than to delinquency. In conclusion, ADHD symptomatology may be a risk factor for delinquency, since some neural information processing deficits found in ADHD seemed to be even more pronounced in offenders with ADHD. However, our results suggest additional risk factors consisting of deviant higher-order visual processing, especially of facial affect, as well as abnormalities in monitoring and evaluative functions of response inhibition.
Resumo:
Anaesthesia causes a respiratory impairment, whether the patient is breathing spontaneously or is ventilated mechanically. This impairment impedes the matching of alveolar ventilation and perfusion and thus the oxygenation of arterial blood. A triggering factor is loss of muscle tone that causes a fall in the resting lung volume, functional residual capacity. This fall promotes airway closure and gas adsorption, leading eventually to alveolar collapse, that is, atelectasis. The higher the oxygen concentration, the faster will the gas be adsorbed and the aleveoli collapse. Preoxygenation is a major cause of atelectasis and continuing use of high oxygen concentration maintains or increases the lung collapse, that typically is 10% or more of the lung tissue. It can exceed 25% to 40%. Perfusion of the atelectasis causes shunt and cyclic airway closure causes regions with low ventilation/perfusion ratios, that add to impaired oxygenation. Ventilation with positive end-expiratory pressure reduces the atelectasis but oxygenation need not improve, because of shift of blood flow down the lung to any remaining atelectatic tissue. Inflation of the lung to an airway pressure of 40 cmH2O recruits almost all collapsed lung and the lung remains open if ventilation is with moderate oxygen concentration (< 40%) but recollapses within a few minutes if ventilation is with 100% oxygen. Severe obesity increases the lung collapse and obstructive lung disease and one-lung anesthesia increase the mismatch of ventilation and perfusion. CO2 pneumoperitoneum increases atelectasis formation but not shunt, likely explained by enhanced hypoxic pulmonary vasoconstriction by CO2. Atelectasis may persist in the postoperative period and contribute to pneumonia.
Resumo:
Back-in-time debuggers are extremely useful tools for identifying the causes of bugs, as they allow us to inspect the past states of objects no longer present in the current execution stack. Unfortunately the "omniscient" approaches that try to remember all previous states are impractical because they either consume too much space or they are far too slow. Several approaches rely on heuristics to limit these penalties, but they ultimately end up throwing out too much relevant information. In this paper we propose a practical approach to back-in-time debugging that attempts to keep track of only the relevant past data. In contrast to other approaches, we keep object history information together with the regular objects in the application memory. Although seemingly counter-intuitive, this approach has the effect that past data that is not reachable from current application objects (and hence, no longer relevant) is automatically garbage collected. In this paper we describe the technical details of our approach, and we present benchmarks that demonstrate that memory consumption stays within practical bounds. Furthermore since our approach works at the virtual machine level, the performance penalty is significantly better than with other approaches.
Resumo:
Optical surveys for space debris in high-altitude orbits have been conducted since more than ten years. Originally these efforts concentrated mainly on the geostationary ring (GEO). Corresponding observation strategies, processing techniques and cataloguing approaches have been developed and successfully applied. The ESA GEO surveys, e.g., resulted in the detection of a significant population of small-size debris and later in the discovery of high area-to-mass ratio objects in GEO-like orbits. The observation scenarios were successively adapted to survey the geostationary transfer orbit (GTO) region; and recently surveys to search for debris in the medium Earth orbit (MEO) region of the global navigation satellite constellations were successfully conducted. Comparably less experience (both, in terms of practical observation and strategy definition) is available for eccentric orbits that (at least partly) are in the MEO region, in particular for the Molniya-type orbits. Several breakup events and deliberate fragmentations are known to have taken place in such orbits. Different survey and follow-up strategies for searching space debris objects in highly-eccentric MEO orbits, and to acquire orbits which are sufficiently accurate to catalogue such objects and to maintain their orbits over longer time spans were developed. Simulations were performed to compare the performance of different survey and cataloguing strategies. Eventually, optical observations were conducted in the framework of an ESA study using ESA’s Space Debris Telescope (ESASDT) the 1-m Zeiss telescope located at the Optical Ground Station (OGS) at the Teide Observatory at Tenerife, Spain. A first series of surveys of Molnjya-type orbits was performed between January and April 2013. During these four months survey observations were performed during nine nights. A basic survey consisted of observing a single geocentric field for 10 minutes. If a faint object was found, follow-up observations were performed during the same night to ensure a save rediscovery of the object during the next nights. Additional follow-up observations to maintain the orbits of these newly discovered faint objects were also acquired with AIUB ́s 1m ZIMLAT telescope in Zimmerwald, Switzerland. Eventually 195 basic surveys were performed during these nine nights corresponding to about 32.5 hours of observations. In total 24 uncorrelated faint objects were discovered and all known catalogue objects in the survey fields were detected. On average one uncorrelated object was found every 80 minutes. Some of these objects show a considerable brightness variation and have a high area-to-mass ratio as determined in the orbit estimation process.
Resumo:
With the availability of lower cost but highly skilled software development labor from offshore regions, entrepreneurs from developed countries who do not have software development experience can utilize this workforce to develop innovative software products. In order to succeed in offshored innovation projects, the often extreme knowledge boundaries between the onsite entrepreneur and the offshore software development team have to be overcome. Prior research has proposed that boundary objects are critical for bridging such boundaries – if they are appropriately used. Our longitudinal, revelatory case study of a software innovation project is one of the first to explore the role of the software prototype as a digital boundary object. Our study empirically unpacks five use practices that transform the software prototype into a boundary object such that knowledge boundaries are bridged. Our findings provide new theoretical insights for literature on software innovation and boundary objects, and have implications for practice.
Resumo:
Answering run-time questions in object-oriented systems involves reasoning about and exploring connections between multiple objects. Developer questions exercise various aspects of an object and require multiple kinds of interactions depending on the relationships between objects, the application domain and the differing developer needs. Nevertheless, traditional object inspectors, the essential tools often used to reason about objects, favor a generic view that focuses on the low-level details of the state of individual objects. This leads to an inefficient effort, increasing the time spent in the inspector. To improve the inspection process, we propose the Moldable Inspector, a novel approach for an extensible object inspector. The Moldable Inspector allows developers to look at objects using multiple interchangeable presentations and supports a workflow in which multiple levels of connecting objects can be seen together. Both these aspects can be tailored to the domain of the objects and the question at hand. We further exemplify how the proposed solution improves the inspection process, introduce a prototype implementation and discuss new directions for extending the Moldable Inspector.
Resumo:
As the number of space debris is increasing in the geostationary ring, it becomes mandatory for any satellite operator to avoid any collisions. Space debris in geosynchronous orbits may be observed with optical telescopes. Other than radar, that requires very large dishes and transmission powers for sensing high-altitude objects, optical observations do not depend on active illumination from ground and may be performed with notably smaller apertures. The detection size of an object depends on the aperture of the telescope, sky background and exposure time. With a telescope of 50 cm aperture, objects down to approximately 50 cm may be observed. This size is regarded as a threshold for the identification of hazardous objects and the prevention of potentially catastrophic collisions in geostationary orbits. In collaboration with the Astronomical Institute of the University of Bern (AIUB), the German Space Operations Center (GSOC) is building a small aperture telescope to demonstrate the feasibility of optical surveillance of the geostationary ring. The telescope will be located in the southern hemisphere and complement an existing telescope in the northern hemisphere already operated by AIUB. These two telescopes provide an optimum coverage of European GEO satellites and enable a continuous monitoring independent of seasonal limitations. The telescope will be operated completely automatically. The automated operations should be demonstrated covering the full range of activities including scheduling of observations, telescope and camera control as well as data processing.
Resumo:
Neolithic wetland sites in the Swiss Plateau provide an extraordinary database for the study of mobilities, entanglements and transformations in material culture. Based on dendrochronologically dated settlements between 3900 and 3500 BC, two regional pottery styles and their local variations are well known, Pfyn and Cortaillod. The vessels share the same habitus and were made of local raw materials. However, some vessels specific to other pottery styles are also present in the sites. By focusing on itineraries of vessels and shifts in pottery knowledge, their appropriation in different contexts and the resulting material entanglements, we want to approach the multiple regimes of mobility: At Lake Constance - known for Pfyn pottery - specific Michelsberg vessels like tulip beakers and lugged jars occur in small numbers. These travelling objects were produced with exogenous raw materials and transported to the sites from Southern Germany. At Concise (Lake Neuchâtel) besides the local Cortaillod pottery the whole repertoire of NMB pottery, characteristic for Eastern France, was also produced. Further cases from the same space-time frame point to other regimes of mobility. In our two PhD-projects we compare pottery practices - styles, techniques, raw materials - from over 20 key sites in the region. Based on Bourdieu’s reflexive anthropology, we apply different qualitative and quantitative archaeological and archaeometrical methods, thus striving for a deeper understanding of habitus and the transformative potential of moving people, objects and ideas on local and regional scales and related social contexts.
Resumo:
Pottery is one of the most common and stylistically differentiated sources in prehistoric archaeology. This might be the reason why it served as a waste projection surface for archaeological notions about culture, identity, and mobility in the past. As we do not have access to emic categorisations of Neolithic societies we focus on contexts of practice in which pottery was incorporated. It is the moment of production, which left some of the clearest traces on the vessels. Different ways of using raw materials, specific techniques, and characteristic pottery styles can be observed. We understand them as a result of habitus, as socially shared internalized schemes, patterns and habits in pottery production. Taking this as a staring point, two main pottery groups can be differed on the Swiss Plateau between 3900 and 3500 BC: the Mediterranean influenced Cortaillod pottery in Western Switzerland and the Danubian influenced Pfyn pottery in North-Eastern Switzerland. These pottery styles were not only entangled to some degree. Furthermore, in some settlements vessels made in “foreign” styles - Michelsberg, Munzingen, Néolithique Moyen Bourguignon - are present too. Some of them were travelling objects, as their nonlocal raw materials show. Others were locally made, indicating long-term mobility of their producers. To analyse these phenomena of mobilites and entanglements in our PhDs we plan to apply different archaeological and archaeometrical methods, thus striving for a deeper understanding of the transformative potential of moving people, objects and ideas in Neolithic societies on the Swiss Plateau.
Resumo:
The currently proposed space debris remediation measures include the active removal of large objects and “just in time” collision avoidance by deviating the objects using, e.g., ground-based lasers. Both techniques require precise knowledge of the attitude state and state changes of the target objects. In the former case, to devise methods to grapple the target by a tug spacecraft, in the latter, to precisely propagate the orbits of potential collision partners as disturbing forces like air drag and solar radiation pressure depend on the attitude of the objects. Non-resolving optical observations of the magnitude variations, so-called light curves, are a promising technique to determine rotation or tumbling rates and the orientations of the actual rotation axis of objects, as well as their temporal changes. The 1-meter telescope ZIMLAT of the Astronomical Institute of the University of Bern has been used to collect light curves of MEO and GEO objects for a considerable period of time. Recently, light curves of Low Earth Orbit (LEO) targets were acquired as well. We present different observation methods, including active tracking using a CCD subframe readout technique, and the use of a high-speed scientific CMOS camera. Technical challenges when tracking objects with poor orbit redictions, as well as different data reduction methods are addressed. Results from a survey of abandoned rocket upper stages in LEO, examples of abandoned payloads and observations of high area-to-mass ratio debris will be resented. Eventually, first results of the analysis of these light curves are provided.
Resumo:
Space debris in geostationary orbits may be detected with optical telescopes when the objects are illuminated by the Sun. The advantage compared to Radar can be found in the illumination: radar illuminates the objects and thus the detection sensitivity depletest proportional to the fourth power of the d istance. The German Space Operation Center, GSOC, together with the Astronomical Institute of the University of Bern, AIUB, are setting up a telescope system called SMARTnet to demonstrate the capability of performing geostationary surveillance. Such a telescope system will consist of two telescopes on one mount: a smaller telescope with an aperture of 20cm will serve for fast survey while the larger one, a telescope with an aperture of 50cm, will be used for follow-up observations. The telescopes will be operated by GSOC from Oberpfaffenhofen by the internal monitoring and control system called SMARTnetMAC. The observation plan will be generated by MARTnetPlanning seven days in advance by applying an optimized planning scheduler, taking into account fault time like cloudy nights, priority of objects etc. From each picture taken, stars will be identified and everything not being a star is treated as a possible object. If the same object can be identified on multiple pictures within a short time span, the trace is called a tracklet. In the next step, several tracklets will be correlated to identify individual objects, ephemeris data for these objects are generated and catalogued . This will allow for services like collision avoidance to ensure safe operations for GSOC’s satellites. The complete data processing chain is handled by BACARDI, the backbone catalogue of relational debris information and is presented as a poster.