8,617 research outputs found
Comparison of Routable Control System Security Approaches
This document is an supplement to the 'Secure and Efficient Routable Control Systems.' It addressed security in routable control system communication. The control system environment that monitors and manages the power grid historically has utilized serial communication mechanisms. Leased-line serial communication environments operating at 1200 to 9600 baud rates are common. However, recent trends show that communication media such as fiber, optical carrier 3 (OC-3) speeds, mesh-based high-speed wireless, and the Internet are becoming the media of choice. In addition, a dichotomy has developed between the electrical transmission and distribution environments, with more modern communication infrastructures deployed by transmission utilities. The preceding diagram represents a typical control system. The Communication Links cloud supports all of the communication mechanisms a utility might deploy between the control center and devices in the field. Current methodologies used for security implementations are primarily led by single vendors or standards bodies. However, these entities tend to focus on individual protocols. The result is an environment that contains a mixture of security solutions that may only address some communication protocols at an increasing operational burden for the utility. A single approach is needed that meets operational requirements, is simple to operate, and provides the necessary level of security for all control system communication. The solution should be application independent (e.g., Distributed Network Protocol/Internet Protocol [DNP/IP], International Electrotechnical Commission [IEC] C37.118, Object Linking and Embedding for Process Control [OPC], etc.) and focus on the transport layer. In an ideal setting, a well-designed suite of standards for control system communication will be used for vendor implementation and compliance testing. An expected outcome of this effort is an international standard
Decoherence-based exploration of d-dimensional one-way quantum computation
We study the effects of amplitude and phase damping decoherence in
d-dimensional one-way quantum computation (QC). Our investigation shows how
information transfer and entangling gate simulations are affected for d>=2. To
understand motivations for extending the one-way model to higher dimensions, we
describe how d-dimensional qudit cluster states deteriorate under environmental
noise. In order to protect quantum information from the environment we consider
the encoding of logical qubits into physical qudits and compare entangled pairs
of linear qubit-cluster states with single qudit clusters of equal length and
total dimension. Our study shows a significant reduction in the performance of
one-way QC for d>2 in the presence of Markovian type decoherence models.Comment: 8 pages, 11 figures, RevTeX
Robotic-assistance does not enhance standard laparoscopic technique for right-sided donor nephrectomy.
OBJECTIVE: To examine donor and recipient outcomes after right-sided robotic-assisted laparoscopic donor nephrectomy (RALDN) compared with standard laparoscopic donor nephrectomy (LDN) and to determine whether robotic-assistance enhances LDN.
MATERIALS & METHODS: From December 2005 to January 2011, 25 patients underwent right-sided LDN or RALDN. An IRB-approved retrospective review was performed of both donor and recipient medical charts. Primary endpoints included both intraoperative and postoperative outcomes.
RESULTS: Twenty right-sided LDNs and 5 RALDNs were performed during the study period. Neither estimated blood loss (76.4 mL vs. 30 mL, P = .07) nor operative time (231 min vs. 218 min, P = .61) were significantly different between either group (LDN vs. RALDN). Warm ischemia time for LDN was 2.6 min vs. 3.8 min for RALDN (P = .44). Donor postoperative serum estimated glomerular filtration rates (eGFR) were similar (53 vs. 59.6 mL/min/1.73 m2, LDN vs. RALDN, P = .26). For the recipient patients, posttransplant eGFR were similar at 6 months (53.4 vs. 59.8 mL/min/1.73 m2, LDN vs. RALDN, P = .53).
CONCLUSION: In this study, robotic-assistance did not improve outcomes associated with LDN. Larger prospective studies are needed to confirm any perceived benefit of RALDN
Positron Emission Tomography Score Has Greater Prognostic Significance Than Pretreatment Risk Stratification in Early-Stage Hodgkin Lymphoma in the UK RAPID Study.
PURPOSE: Accurate stratification of patients is an important goal in Hodgkin lymphoma (HL), but the role of pretreatment clinical risk stratification in the context of positron emission tomography (PET) -adapted treatment is unclear. We performed a subsidiary analysis of the RAPID trial to assess the prognostic value of pretreatment risk factors and PET score in determining outcomes. PATIENTS AND METHODS: Patients with stage IA to IIA HL and no mediastinal bulk underwent PET assessment after three cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine; 143 PET-positive patients (PET score, 3 to 5) received a fourth doxorubicin, bleomycin, vinblastine, and dacarbazine cycle and involved-field radiotherapy, and 419 patients in complete metabolic remission were randomly assigned to receive involved-field radiotherapy (n = 208) or no additional treatment (n = 211). Cox regression was used to investigate the association between PET score and pretreatment risk factors with HL-specific event-free survival (EFS). RESULTS: High PET score was associated with inferior EFS, before (P .4). CONCLUSION: In RAPID, a positive PET scan did not carry uniform prognostic weight; only a PET score of 5 was associated with inferior outcomes. This suggests that in future trials involving patients without B symptoms or mediastinal bulk, a score of 5 rather than a positive PET result should be used to guide treatment escalation in early-stage HL
Evaluating the sensitivity of hybridization-based epigenotyping using a methyl binding domain protein
Hypermethylation of CpG islands in gene promoter regions has been shown to be a predictive biomarker for certain diseases. Most current methods for methylation profiling are not well-suited for clinical analysis. Here, we report the development of an inexpensive device and an epigenotyping assay with a format conducive to multiplexed analysis.David H. Koch Institute for Integrative Cancer Research at MIT (First-year Graduate Fellowship)National Science Foundation (U.S.). Graduate Research FellowshipBurroughs Wellcome Fund (Career Award at the Scientific Interface)National Institute of Environmental Health Sciences (Grant P30-ES002109)Massachusetts Institute of Technology. James H. Ferry Fund for Innovation in Research Educatio
Efficacies of liposome-encapsulated streptomycin and ciprofloxacin against Mycobacterium avium-M. intracellulare complex infections in human peripheral blood monocyte/macrophages
Current treatments of disseminated infection caused by the Mycobacterium avium-M. intracellulare complex (MAC) are generally ineffective. Liposome- mediated delivery of antibiotics to MAC-infected tissues in vivo can enhance the efficacy of the drugs (N. Duzgunes, V. K. Perumal, L. Kesavalu, J. A. Goldstein, R. J. Debs, and P. R. J. Gangadharam, Antimicrob. Agents Chemother. 32:1404-1411, 1988; N. Duzgunes, D. A. Ashtekar, D. L. Flasher, N. Ghori, R. J. Debs, D. S. Friend, and P. R. J. Gangadharam, J. Infect. Dis. 164:143-151, 1991). We investigated the therapeutic efficacies of liposome- encapsulated streptomycin and ciprofloxacin against growth of the MAC inside human peripheral blood monocyte/macrophages. Treatment was initiated 24 h after infection of macrophages with the MAC and stopped after 20 h, and the cells were incubated for another 7 days. The antimycobacterial activity of streptomycin was enhanced when the drug was delivered to macrophages in liposome-encapsulated form, reducing the CFU about threefold more than the free drug did throughout the concentration range studied (10 to 50 μg/ml). With 50 μg of encapsulated streptomycin per ml, the CFU were reduced to 11% of the initial level of infection. Liposome-encapsulated ciprofloxacin was at least 50 times more effective against the intracellular bacteria than was the free drug: at a concentration of 0.1 μg/ml, liposome-encapsulated ciprofloxacin had greater antimycobacterial activity than the free drug at 5 μg/ml. With liposome-encapsulated ciprofloxacin at 5 μg/ml, the CFU were reduced by more than 1,000-fold at the end of the 7-day incubation period, compared with untreated controls. These results suggest that liposome- encapsulated ciprofloxacin or other fluoroquinolones may be effective against MAC infections in vivo
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Impact of Extended Daylight Saving Time on National Energy Consumption Report to Congress
The Energy Policy Act of 2005 (Pub. L. No. 109-58; EPAct 2005) amended the Uniform Time Act of 1966 (Pub. L. No. 89-387) to increase the portion of the year that is subject to Daylight Saving Time. (15 U.S.C. 260a note) EPAct 2005 extended the duration of Daylight Saving Time in the spring by changing its start date from the first Sunday in April to the second Sunday in March, and in the fall by changing its end date from the last Sunday in October to the first Sunday in November. (15 U.S.C. 260a note) EPAct 2005 also called for the Department of Energy to evaluate the impact of Extended Daylight Saving Time on energy consumption in the United States and to submit a report to Congress. (15 U.S.C. 260a note) This report presents the results of impacts of Extended Daylight Saving Time on the national energy consumption in the United States. The key findings are: (1) The total electricity savings of Extended Daylight Saving Time were about 1.3 Tera Watt-hour (TWh). This corresponds to 0.5 percent per each day of Extended Daylight Saving Time, or 0.03 percent of electricity consumption over the year. In reference, the total 2007 electricity consumption in the United States was 3,900 TWh. (2) In terms of national primary energy consumption, the electricity savings translate to a reduction of 17 Trillion Btu (TBtu) over the spring and fall Extended Daylight Saving Time periods, or roughly 0.02 percent of total U.S. energy consumption during 2007 of 101,000 TBtu. (3) During Extended Daylight Saving Time, electricity savings generally occurred over a three- to five-hour period in the evening with small increases in usage during the early-morning hours. On a daily percentage basis, electricity savings were slightly greater during the March (spring) extension of Extended Daylight Saving Time than the November (fall) extension. On a regional basis, some southern portions of the United States exhibited slightly smaller impacts of Extended Daylight Saving Time on energy savings compared to the northern regions, a result possibly due to a small, offsetting increase in household air conditioning usage. (4) Changes in national traffic volume and motor gasoline consumption for passenger vehicles in 2007 were determined to be statistically insignificant and therefore, could not be attributed to Extended Daylight Saving Time
Arrays of Cooper Pair Boxes Coupled to a Superconducting Reservoir: `Superradiance' and `Revival.'
We consider an array of Cooper Pair Boxes, each of which is coupled to a
superconducting reservoir by a capacitive tunnel junction. We discuss two
effects that probe not just the quantum nature of the islands, but also of the
superconducting reservoir coupled to them. These are analogues to the
well-known quantum optical effects `superradiance,' and `revival.' When revival
is extended to multiple systems, we find that `entanglement revival' can also
be observed. In order to study the above effects, we utilise a highly
simplified model for these systems in which all the single-electron energy
eigenvalues are set to be the same (the strong coupling limit), as are the
charging energies of the Cooper Pair Boxes, allowing the whole system to be
represented by two large coupled quantum spins. Although this simplification is
drastic, the model retains the main features necessary to capture the phenomena
of interest. Given the progress in superconducting box experiments over recent
years, it is possible that experiments to investigate both of these interesting
quantum coherent phenomena could be performed in the forseeable future.Comment: 23 pages, 5 figures Clarifications made as recommended by refere
Method for determining antiphase dynamics in a multimode laser
We measure the cross spectrum of the intensity fluctuations of pairs of modes for a multilongitudinal mode neodymium-doped yttrium aluminum garnet laser operating in the steady state regime. From the data we build up a picture of how the longitudinal mode fluctuations interfere and directly show the antiphase dynamics of the intensity fluctuations.T. Hill, L. Stamatescu and M. W. Hamilto
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