New neighborhood based rough sets

Neighborhood based rough sets are important generalizations of the classical rough sets of Pawlak, as neighborhood operators generalize equivalence classes. In this article, we introduce nine neighborhood based operators and we study the partial order relations between twenty-two different neighborhood operators obtained from one covering. Seven neighborhood operators result in new rough set approximation operators. We study how these operators are related to the other fifteen neighborhood based approximation operators in terms of partial order relations, as well as to seven non-neighborhood-based rough set approximation operators

Stochastic Stokes' drift of a flexible dumbbell

We consider the stochastic Stokes drift of a flexible dumbbell. The dumbbell consists of two isotropic Brownian particles connected by a linear spring with zero natural length, and is advected by a sinusoidal wave. We find an asymptotic approximation for the Stokes drift in the limit of a weak wave, and find good agreement with the results of a Monte Carlo simulation. We show that it is possible to use this effect to sort particles by their flexibility even when all the particles have the same diffusivity.Comment: 12 pages, 1 figur

Next Generation NASA Hazard Detection System Development

The SPLICE project is continuing NASAs efforts to develop precision landing GN&C technologies for future lander missions. One of those technologies is the next generation Hazard Detection (HD) System, which consists of a new HD Lidar and HD Algorithms. The HD System is a modular system that will be adapted to meet specific mission needs in the future. This paper presents the design approach, the nominal concept of operations for which the first prototype is being designed, and the expected performance of the system

The impact of empiric antimicrobial therapy with a β-lactam and fluoroquinolone on mortality for patients hospitalized with severe pneumonia

INTRODUCTION: National clinical practice guidelines have recommended specific empiric antimicrobial regimes for patients with severe community-acquired pneumonia. However, evidence confirming improved mortality with many of these regimes is lacking. Our aim was to determine the association between the empiric use of a β-lactam with fluoroquinolone, compared with other recommended antimicrobial therapies, and mortality in patients hospitalized with severe community-acquired pneumonia. METHODS: A retrospective observational study was conducted at two tertiary teaching hospitals. Eligible subjects were admitted with a diagnosis of community-acquired pneumonia and had a chest X-ray and a discharge ICD-9 diagnosis consistent with this. Subjects were excluded if they received 'comfort measures only' during the admission, had been transferred from another acute care hospital, did not meet criteria for severe pneumonia, or were treated with non-guideline-concordant antibiotics. A multivariable logistic regression model was used to assess the association between 30-day mortality and the use of a β-lactam antibiotic with a fluoroquinolone compared with other guideline-concordant therapies, after adjustment for potential confounders including a propensity score. RESULTS: Data were abstracted on 172 subjects at the two hospitals. The mean age was 63.5 years (SD 15.0). The population was 88% male; 91% were admitted through the emergency department and 62% were admitted to the intensive care unit within the first 24 hours after admission. Mortality was 19.8% at 30 days. After adjustment for potential confounders the use of a β-lactam with a fluoroquinolone (odds ratio 2.71, 95% confidence interval 1.2 to 6.1) was associated with increased mortality. CONCLUSION: The use of initial empiric antimicrobial therapy with a β-lactam and a fluoroquinolone was associated with increased short-term mortality for patients with severe pneumonia in comparison with other guideline-concordant antimicrobial regimes. Further research is needed to determine the range of appropriate empiric antimicrobial therapies for patients with severe community-acquired pneumonia

NASA SPLICE Project: Development and Testing of Precision Landing GN&C Technologies

NASA's technology advancement needs for entry, descent and landing call for high-precision, high-rate sensors that can improve navigation accuracy and vehicle control performance. Higher landing accuracy is required for any future human lander missions, and likely, for most robotic missions 1,2. Sensors and algorithms that significantly reduce navigation errors and can image the local terrain will enable landing at locations of high scientific interest that would otherwise pose significant risk to the vehicle. The Safe and Precise Landing-Integrated Capabilities Evolution project, or SPLICE, is developing precision landing and hazard avoidance (PL&HA) technologies for NASA and for potential commercial space flight missions. SPLICE technologies include sensors, algorithms, advanced space flight computing capabilities, and simulation tools used to integrate and study guidance, navigation, and control (GN&C) system performance. SPLICE efforts include hardware-in-the-loop (HWIL) simulation testing, ground testing, and flight testing, including reuse of hardware from the CoOperative Blending of Autonomous Landing Technologies (COBALT) suborbital flight-test payload3,4. Two of the precise navigation sensors that are being developed and matured within SPLICE are LiDARs. Since 2006, NASA Langley has been developing a Navigation Doppler LiDAR (NDL) for precise velocity measurements, and SPLICE is building an NDL engineering test unit (ETU) that will be brought up to TRL 6 following environmental and high-speed1,2 testing. NASA Goddard is developing a Hazard Detection LiDAR (HD LiDAR) engineering development unit (EDU) for SPLICE that has relevance to future human and robotic lander missions. The HD LiDAR will be flight test and matured to TRL 5

DNA Repair Mechanisms as Drug Targets in Prokaryotes

Nowadays, a great amount of pathogenic bacteria has been identified such as Mycobacterium sp. and Helicobacter pylori and have become a serious health problem around the world. These bacteria have developed several DNA repair mechanisms as a strategy to neutralize the effect of the exposure to endogenous and exogenous agents that will lead to two different kinds of DNA damage: single strand breaks (SSBs) and double strand breaks (DSBs). For SSBs repair, bacteria use the base excision repair (BER) and nucleotide excision repair (NER) mechanisms, which fix the damaged strand replacing the damaged base or nucleotide. DSBs repair in bacteria is performed by homologous recombination repair (HRR) and non-homologous end-joining (NHEJ). HRR uses the homologous sequence to fix the two damaged strand, while NHEJ repair does not require the use of its homologous sequence. The use of unspecific antibiotics to treat bacterial infections has caused a great deal of multiple resistant strains making less effective the current therapies with antibiotics. In this review, we emphasized the mechanisms mentioned above to identify molecular targets that can be used to develop novel and more efficient drugs in future.Nowadays, a great amount of pathogenic bacteria has been identified such as Mycobacterium sp. and Helicobacter pylori and have become a serious health problem around the world. These bacteria have developed several DNA repair mechanisms as a strategy to neutralize the effect of the exposure to endogenous and exogenous agents that will lead to two different kinds of DNA damage: single strand breaks (SSBs) and double strand breaks (DSBs). For SSBs repair, bacteria use the base excision repair (BER) and nucleotide excision repair (NER) mechanisms, which fix the damaged strand replacing the damaged base or nucleotide. DSBs repair in bacteria is performed by homologous recombination repair (HRR) and non-homologous end-joining (NHEJ). HRR uses the homologous sequence to fix the two damaged strand, while NHEJ repair does not require the use of its homologous sequence. The use of unspecific antibiotics to treat bacterial infections has caused a great deal of multiple resistant strains making less effective the current therapies with antibiotics. In this review, we emphasized the mechanisms mentioned above to identify molecular targets that can be used to develop novel and more efficient drugs in future

Open-Loop Flight Testing of COBALT GN&C Technologies for Precise Soft Landing

A terrestrial, open-loop (OL) flight test campaign of the NASA COBALT (CoOperative Blending of Autonomous Landing Technologies) platform was conducted onboard the Masten Xodiac suborbital rocket testbed, with support through the NASA Advanced Exploration Systems (AES), Game Changing Development (GCD), and Flight Opportunities (FO) Programs. The COBALT platform integrates NASA Guidance, Navigation and Control (GN&C) sensing technologies for autonomous, precise soft landing, including the Navigation Doppler Lidar (NDL) velocity and range sensor and the Lander Vision System (LVS) Terrain Relative Navigation (TRN) system. A specialized navigation filter running onboard COBALT fuzes the NDL and LVS data in real time to produce a precise navigation solution that is independent of the Global Positioning System (GPS) and suitable for future, autonomous planetary landing systems. The OL campaign tested COBALT as a passive payload, with COBALT data collection and filter execution, but with the Xodiac vehicle Guidance and Control (G&C) loops closed on a Masten GPS-based navigation solution. The OL test was performed as a risk reduction activity in preparation for an upcoming 2017 closed-loop (CL) flight campaign in which Xodiac G&C will act on the COBALT navigation solution and the GPS-based navigation will serve only as a backup monitor

Antibody Fc Glycosylation Discriminates Between Latent and Active Tuberculosis

Background. Mycobacterium tuberculosis remains a global health problem and clinical management is complicated by difficulty in discriminating between latent infection and active disease. While M. tuberculosis-reactive antibody levels are heterogeneous, studies suggest that levels of IgG glycosylation differ between disease states. Here we extend this observation across antibody domains and M. tuberculosis specificities to define changes with the greatest resolving power. Methods. Capillary electrophoretic glycan analysis was performed on bulk non-antigen–specific IgG, bulk Fc domain, bulk Fab domain, and purified protein derivative (PPD)- and Ag85A-specific IgG from subjects with latent (n = 10) and active (n = 20) tuberculosis. PPD-specific isotype/subclass, PPD-specific antibody-dependent phagocytosis, cellular cytotoxicity, and natural killer cell activation were assessed. Discriminatory potentials of antibody features were evaluated individually and by multivariate analysis. Results. Parallel profiling of whole, Fc, and Fab domain-specific IgG glycosylation pointed to enhanced differential glycosylation on the Fc domain. Differential glycosylation was observed across antigen-specific antibody populations. Multivariate modeling highlighted Fc domain glycan species as the top discriminatory features, with combined PPD IgG titers and Fc domain glycans providing the highest classification accuracy. Conclusions. Differential glycosylation occurs preferentially on the Fc domain, providing significant discriminatory power between different states of M. tuberculosis infection and disease