3,936 research outputs found

    Ultraminiature television camera

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    Ultraminiature television camera with a total volume of 20.25 cubic inches, requires 28 vdc power, operates on UHF and accommodates standard 8-mm optics. It uses microelectronic assembly packaging techniques and contains a magnetically deflected and electrostatically focused vidicon, automatic gain control circuit, power supply, and transmitter

    Characterizing 2-crossing-critical graphs

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    It is very well-known that there are precisely two minimal non-planar graphs: K5K_5 and K3,3K_{3,3} (degree 2 vertices being irrelevant in this context). In the language of crossing numbers, these are the only 1-crossing-critical graphs: they each have crossing number at least one, and every proper subgraph has crossing number less than one. In 1987, Kochol exhibited an infinite family of 3-connected, simple 2-crossing-critical graphs. In this work, we: (i) determine all the 3-connected 2-crossing-critical graphs that contain a subdivision of the M\"obius Ladder V10V_{10}; (ii) show how to obtain all the not 3-connected 2-crossing-critical graphs from the 3-connected ones; (iii) show that there are only finitely many 3-connected 2-crossing-critical graphs not containing a subdivision of V10V_{10}; and (iv) determine all the 3-connected 2-crossing-critical graphs that do not contain a subdivision of V8V_{8}.Comment: 176 pages, 28 figure

    Maps for Electron Clouds: Application to LHC Conditioning

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    In this communication we present a generalization of the map formalism, introduced in [1] and [2], to the analysis of electron flux at the chamber wall with particular reference to the exploration of LHC conditioning scenarios.Comment: 3 pages, 4 figure

    The impact of significant input of fine sediment on benthic fauna at tributary junctions: a case study of the Bermejo-Paraguay River confluence, Argentina

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    This study examines the morphological features, suspended sediment inputs and hydraulic conditions within a large river in association with ecological patterns before and after a tributary confluence. In order to examine these effects, the macroinvertebrate distributions from three reaches of the Paraguay and Bermejo Rivers (Paraguay-Argentina) are investigated. The Bermejo River is a tributary that supplies significant quantities of fine sediment to the Paraguay River, primarily in suspension. Two reaches were examined on the Paraguay River, upstream and downstream of the Bermejo River junction, with the third study reach located on the Bermejo River, upstream of the confluence with the Paraguay River. The results provide clear evidence that a significantly increased loading of fine sediment at a river confluence has effects on the distribution and potential movement of benthic invertebrates in the lotic environment by representing physical barriers at affected sites. These effects may be important at both local and regional scales, and such increases in suspended sediment (especially associated with anthropogenic change) may thus pose a major threat to ecosystem integrity that has been historically underestimated

    Efficacy of Two Common Methods of Application of Residual Insecticide for Controlling the Asian Tiger Mosquito, Aedes albopictus (Skuse), in Urban Areas

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    After its first introduction in the 1980's the Asian tiger mosquito, Aedes albopictus (Skuse), has spread throughout Southern Europe. Ae. albopictus is considered an epidemiologically important vector for the transmission of many viral pathogens such as the yellow fever virus, dengue fever and Chikungunya fever, as well as several filarial nematodes such as Dirofilaria immitis or D. repens. It is therefore crucial to develop measures to reduce the risks of disease transmission by controlling the vector populations. The aim of the study was to compare the efficacy of two application techniques (mist vs. stretcher sprayer) and two insecticides (Etox based on the nonester pyrethroid Etofenprox vs. Microsin based on the pyrethroid type II Cypermetrin) in controlling adult tiger mosquito populations in highly populated areas. To test the effect of the two treatments pre- and post-treatment human landing rate counts were conducted for two years. After one day from the treatment we observed a 100% population decrease in mosquito abundance with both application methods and both insecticides. However, seven and 14 days after the application the stretcher sprayer showed larger population reductions than the mist sprayer. No effect of insecticide type after one day and 14 days was found, while Etox caused slightly higher population reduction than Microsin after seven days. Emergency measures to locally reduce the vector populations should adopt adulticide treatments using stretcher sprayers. However, more research is still needed to evaluate the potential negative effects of adulticide applications on non-target organisms

    Law, human capital, and the emergence of free city-states in medieval Italy

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    In this paper, we study how the birth of the first universities in Italy affected the emergence of the Italian free cities-states (the commune) in the period 1000-1300 a.d. Exploiting a panel dataset of 121 cities, we show that after the foundation of a new university the distance between each city in the sample and the university negatively predicts the timing of the birth of communal institutions in the city. Our evidence is consistent with the idea that universities in the Middle Ages provided the necessary juridical knowledge and skills to build legal capacity and develop broader-based institutions.This paper considers how the foundation of the first universities in Italy affected the emergence of free city-states (the communes) in the period 1000-1300 CE. Exploiting a panel dataset of 121 cities, we show that the time variant distance of the sample cities to their closest university is inversely correlated with the probability of their transition to communal institutions. Our evidence is consistent with the hypothesis that the medieval universities provided the useful juridical knowledge and skills for building legal capacity and developing communal institutions

    Seasonal variability in the Central Mediterranean Sea circulation

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    International audienceA high resolution eddy-resolving primitive equation numerical model, based on the Princeton Ocean Model (POM), is used to study the seasonal variability of the general circulation in the Central Mediterranean Sea. The model is run on a seasonal cycle, perpetual year simulation for five years, with nesting to the coarser resolution Ocean General Circulation Model (OGCM), covering the whole Mediterranean Sea. The model results are compared to the current knowledge on the hydrography and dynamics of the area, with a special focus on the annual cycle of the Modified Atlantic Water (MAW), on the circulation in the Sardinia Channel, the water exchange across the Strait of Sicily, and on the transition and fate of the Levantine Intermediate Water (LIW). The results show that the adopted coupling techniques between the two models give a proficient downscaling of the large-scale OGCM flow field into the regional scale model. The numerical solution is also used to highlight the seasonal characteristics of important dynamical features in the area, as well as to shed light on the scarcely known circulation regimes along the north African shelf and slope. Key words. Oceanography: general (numerical modelling); Oceanography: physical (currents; general circulation

    Attacks by “Anonymous” WikiLeaks Proponents not Anonymous

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    On November 28, 2010, the world started watching the whistle blower website WikiLeaks to begin publishing part of the 250,000 US Embassy Diplomatic cables. These confidential cables provide an insight on U.S. international affairs from 274 different embassies, covering topics such as analysis of host countries and leaders and even requests for spying out United Nations leaders.\ud The release of these cables has caused reactions not only in the real world, but also on the Internet. In fact, a cyberwar started just before the initial release. Wikileaks has reported that their servers were experiencing distributed denial-of-service attacks (DDoS). A DDoS attack consists of many computers trying to overload a server by firing a high number of requests, leading ultimately to service disruption. In this case, the goal was to avoid the release of the embassy cables.\ud After the initial cable release, several companies started severed ties with WikiLeaks. One of the first was Amazon.com, that removed the WikiLeaks web- site from their servers. Next, EveryDNS, a company in which the domain wikileaks.org was registered, dropped the domain entries from its servers. On December 4th, PayPal cancelled the account that WikiLeaks was using to receive on-line donations. On the 6th, Swiss bank PostFinance froze the WikiLeaks assets and Mastercard stopped receiving payments to the WikiLeaks account. Visa followed Mastercard on December 7th.\ud These reactions caused a group of Internet activists (or “hacktivists”) named Anonymous to start a retaliation against PostFinance, PayPay, MasterCard, Visa, Moneybrookers.com and Amazon.com, named “Operation Payback”. The retaliation was performed as DDoS attacks to the websites of those companies, disrupting their activities (except for the case of Amazon.com) for different periods of time.\ud The Anonymous group consists of volunteers that use a stress testing tool to perform the attacks. This tool, named LOIC (Low Orbit Ion Cannon), can be found both as a desktop application and as a Web page.\ud Even though the group behind the attacks claims to be anonymous, the tools they provide do not offer any security services, such as anonymization. As a consequence, a hacktivist that volunteers to take part in such attacks, can be traced back easily. This is the case for both current versions of the LOIC tool. Therefore, the goal of this report is to present an analysis of privacy issues in the context of these attacks, and raise awareness on the risks of taking part in them

    Effectiveness evaluation of STOL transport operations

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    A short-takeoff and landing (STOL) systems simulation model has been developed and implemented in a computer code (known as STOL OPS) which permits evaluation of the operation of a STOL aircraft and its avionics in a commercial airline operating environment. STOL OPS concentrated on the avionics functions of navigation, guidance, control, communication, hazard aviodance, and systems management. External world factors influencing the operation of the STOL aircraft include each airport and its geometry, air traffic at each airport, air traffic control equipment and procedures, weather (including winds and visibility), and the flight path between each airport served by the route. The development of the STOL OPS program provides NASA a set of computer programs which can be used for detailed analysis of a STOL aircraft and its avionics and permit establishment of system requirements as a function of airline mission performance goals
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