4,438 research outputs found

    Facebook | Panopticon: an analysis of Facebook and its parallels to the Foucaultian Panopticon

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    A panopticon—the ideal mechanism for surveillance and control—has become embedded in our smartphones and our web browsers. It now pervades the fabric of approximately 890 million daily lives. It is called Facebook. This platform, on which users document their own lives in front of an audience while simultaneously surveilling the lives of their “friends,” shares startling similarities to a prison model, the Panopticon, designed in the late eighteenth-century by Jeremy Bentham, and analyzed by French philosopher, Michel Foucault. Through an analysis of Facebook’s structure and function, parallels will be suggested between the structure of Facebook and the structure of the Panopticon, as well as between strategies Facebook implements and disciplinary strategies implemented inside the Panopticon and described in Foucault’s larger discussion of the evolution of disciplines and punishments. Cultural implications of these similarities will also be addressed, especially those that arise in a Post-Snowden era in which internet-users in general, have reason to assume an overall lack of privacy and security online. Though an overall distrust may be appropriate, individuals still use social media sites and Facebook remains the dominant social media network worldwide. Thus, similarities between Facebook and the Panopticon within a larger cultural context begin to raise questions as to why individuals choose to stay in networks they may not trust and whether or not an exploitation of information given online by an individual might still elicit an adverse response

    Synchronization Strings: Explicit Constructions, Local Decoding, and Applications

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    This paper gives new results for synchronization strings, a powerful combinatorial object that allows to efficiently deal with insertions and deletions in various communication settings: \bullet We give a deterministic, linear time synchronization string construction, improving over an O(n5)O(n^5) time randomized construction. Independently of this work, a deterministic O(nlog2logn)O(n\log^2\log n) time construction was just put on arXiv by Cheng, Li, and Wu. We also give a deterministic linear time construction of an infinite synchronization string, which was not known to be computable before. Both constructions are highly explicit, i.e., the ithi^{th} symbol can be computed in O(logi)O(\log i) time. \bullet This paper also introduces a generalized notion we call long-distance synchronization strings that allow for local and very fast decoding. In particular, only O(log3n)O(\log^3 n) time and access to logarithmically many symbols is required to decode any index. We give several applications for these results: \bullet For any δ0\delta0 we provide an insdel correcting code with rate 1δϵ1-\delta-\epsilon which can correct any O(δ)O(\delta) fraction of insdel errors in O(nlog3n)O(n\log^3n) time. This near linear computational efficiency is surprising given that we do not even know how to compute the (edit) distance between the decoding input and output in sub-quadratic time. We show that such codes can not only efficiently recover from δ\delta fraction of insdel errors but, similar to [Schulman, Zuckerman; TransInf'99], also from any O(δ/logn)O(\delta/\log n) fraction of block transpositions and replications. \bullet We show that highly explicitness and local decoding allow for infinite channel simulations with exponentially smaller memory and decoding time requirements. These simulations can be used to give the first near linear time interactive coding scheme for insdel errors

    Molecular and cellular aspects of re-entrant arrhythmias

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    In recent years it has become evident that myocardial tissue undergoes remodeling in diseased states such as myocardial infarction and hypertrophy which affects membrane channels, cell-to-cell coupling as well as the connective tissue matrix. Although the detailed mechanisms of ventricular arrhythmias in ventricular hypertrophy are not known, studies carried, out by computer simulations or high resolution mapping of electrical activity have suggested a complex interaction between changing ionic currents at the level of the cell membranes, altered cell-to-cell coupling and altered macroscopic structure. The present report summarises these recent developments and their potential relevance for arrhythmogenesi

    Modeling regional aerosol and aerosol precursor variability over California and its sensitivity to emissions and long-range transport during the 2010 CalNex and CARES campaigns

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    The performance of the Weather Research and Forecasting regional model with chemistry (WRF-Chem) in simulating the spatial and temporal variations in aerosol mass, composition, and size over California is quantified using the extensive meteorological, trace gas, and aerosol measurements collected during the California Nexus of Air Quality and Climate Experiment (CalNex) and the Carbonaceous Aerosol and Radiative Effects Study (CARES) conducted during May and June of 2010. The overall objective of the field campaigns was to obtain data needed to better understand processes that affect both climate and air quality, including emission assessments, transport and chemical aging of aerosols, aerosol radiative effects. Simulations were performed that examined the sensitivity of aerosol concentrations to anthropogenic emissions and to long-range transport of aerosols into the domain obtained from a global model. The configuration of WRF-Chem used in this study is shown to reproduce the overall synoptic conditions, thermally driven circulations, and boundary layer structure observed in region that controls the transport and mixing of trace gases and aerosols. Reducing the default emissions inventory by 50% led to an overall improvement in many simulated trace gases and black carbon aerosol at most sites and along most aircraft flight paths; however, simulated organic aerosol was closer to observed when there were no adjustments to the primary organic aerosol emissions. We found that sulfate was better simulated over northern California whereas nitrate was better simulated over southern California. While the overall spatial and temporal variability of aerosols and their precursors were simulated reasonably well, we show cases where the local transport of some aerosol plumes were either too slow or too fast, which adversely affects the statistics quantifying the differences between observed and simulated quantities. Comparisons with lidar and in situ measurements indicate that long-range transport of aerosols from the global model was likely too high in the free troposphere even though their concentrations were relatively low. This bias led to an over-prediction in aerosol optical depth by as much as a factor of 2 that offset the under-predictions of boundary-layer extinction resulting primarily from local emissions. Lowering the boundary conditions of aerosol concentrations by 50% greatly reduced the bias in simulated aerosol optical depth for all regions of California. This study shows that quantifying regional-scale variations in aerosol radiative forcing and determining the relative role of emissions from local and distant sources is challenging during 'clean' conditions and that a wide array of measurements are needed to ensure model predictions are correct for the right reasons. In this regard, the combined CalNex and CARES data sets are an ideal test bed that can be used to evaluate aerosol models in great detail and develop improved treatments for aerosol processes

    Active cooling control of the CLEO detector using a hydrocarbon coolant farm

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    We describe a novel approach to particle-detector cooling in which a modular farm of active coolant-control platforms provides independent and regulated heat removal from four recently upgraded subsystems of the CLEO detector: the ring-imaging Cherenkov detector, the drift chamber, the silicon vertex detector, and the beryllium beam pipe. We report on several aspects of the system: the suitability of using the aliphatic-hydrocarbon solvent PF(TM)-200IG as a heat-transfer fluid, the sensor elements and the mechanical design of the farm platforms, a control system that is founded upon a commercial programmable logic controller employed in industrial process-control applications, and a diagnostic system based on virtual instrumentation. We summarize the system's performance and point out the potential application of the design to future high-energy physics apparatus.Comment: 21 pages, LaTeX, 5 PostScript figures; version accepted for publication in Nuclear Instruments and Methods in Physics Research

    An Extended View of Ozone and Chemistry in the Atmosphere of Mars

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    We present an ongoing effort to characterize chemistry in Mars' atmosphere in multiple seasons on timescales longer than spaceflight missions through coordinated efforts by GSFC's HIPWAC spectrometer and Mars Express SPICAM, archival measurements, and tests/application of photochemical models. The trace species ozone (03) is an effective probe of Mars' atmospheric chemistry because it is destroyed by odd-hydrogen species (HOx, from water vapor photolysis). Observed ozone is a critical test for specific predictions by 3-D photochemical models (spatial, diurnal, seasonal). Coordinated measurements by HIPWAC and SPICAM quantitatively linked mission data to the 23-year GSFC ozone data record and also revealed unanticipated inter-decadal variability of same-season ozone abundances, a possible indicator of changing cloud activity (heterogeneous sink for HOx). A detailed study of long-term conditions is critical to characterizing the predictability of Mars' seasonal chemical behavior, particularly in light of the implications of and the lack of explanation for reported methane behavior

    Quantifying black carbon deposition over the Greenland ice sheet from forest fires in Canada

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    Black carbon (BC) concentrations observed in 22 snowpits sampled in the northwest sector of the Greenland ice sheet in April 2014 have allowed us to identify a strong and widespread BC aerosol deposition event, which was dated to have accumulated in the pits from two snow storms between 27 July and 2 August 2013. This event comprises a significant portion (57% on average across all pits) of total BC deposition over 10 months (July 2013 to April 2014). Here we link this deposition event to forest fires burning in Canada during summer 2013 using modeling and remote sensing tools. Aerosols were detected by both the Cloud‐Aerosol Lidar with Orthogonal Polarization (on board CALIPSO) and Moderate Resolution Imaging Spectroradiometer (Aqua) instruments during transport between Canada and Greenland. We use high‐resolution regional chemical transport modeling (WRF‐Chem) combined with high‐resolution fire emissions (FINNv1.5) to study aerosol emissions, transport, and deposition during this event. The model captures the timing of the BC deposition event and shows that fires in Canada were the main source of deposited BC. However, the model underpredicts BC deposition compared to measurements at all sites by a factor of 2–100. Underprediction of modeled BC deposition originates from uncertainties in fire emissions and model treatment of wet removal of aerosols. Improvements in model descriptions of precipitation scavenging and emissions from wildfires are needed to correctly predict deposition, which is critical for determining the climate impacts of aerosols that originate from fires

    Canine distemper virus neutralization activity is low in human serum and it is sensitive to an amino acid substitution in the hemagglutinin protein

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    © 2015 Elsevier Inc.Serum was analyzed from 146 healthy adult volunteers in eastern Africa to evaluate measles virus (MV) and canine distemper virus (CDV) neutralizing antibody (nAb) prevalence and potency. MV plaque reduction neutralization test (PRNT) results indicated that all sera were positive for MV nAbs. Furthermore, the 50% neutralizing dose (ND50) for the majority of sera corresponded to antibody titers induced by MV vaccination. CDV nAbs titers were low and generally were detected in sera with high MV nAb titers. A mutant CDV was generated that was less sensitive to neutralization by human serum. The mutant virus genome had 10 nucleotide substitutions, which coded for single amino acid substitutions in the fusion (F) and hemagglutinin (H) glycoproteins and two substitutions in the large polymerase (L) protein. The H substitution occurred in a conserved region involved in receptor interactions among morbilliviruses, implying that this region is a target for cross-reactive neutralizing antibodies
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