ATPG for Reversible Circuits using Technology-Related Fault Models

We address the problem of test set generation and test set reduction, to first detect, and later localize faults occurring in reversible circuits. Reversible Computation has high promise of low power consumption. Some new fault models are first presented here. An explanation of the new fault models is made based on a physical realization representing the state of the art in the reversible CMOS circuit technology. Evidence is then presented showing that the fault models presented in the current literature are not adequate for existing realizations of reversible logic such as CMOS. We designed a ATPG software package with a friendly graphical user interface to aid experimentation with various fault models. The purpose of this work is to give an overview of our findings and pave the way for a later paper fully addressing the CMOS fault models. The key experimental results are presented

Assessing syringe exchange program access among persons who inject drugs (PWID) in the District of Columbia

Prior research has explored spatial access to syringe exchange programs (SEPs) among persons who inject drugs (PWID), but these studies have been based on limited data from short periods of time. No research has explored changes in spatial access to SEPs among PWID longitudinally. The purpose of this research is to examine spatial access to SEPs among PWID who accessed services at a SEP in Washington, District of Columbia (DC), from 1996 to 2010. The geometric point distance estimation technique was used to calculate the mean walking distance PWID traveled from the centroid point of their zip code of home residence to the mobile exchange site where they accessed SEP services. Analysis of variance (ANOVA) was used to examine differences in walking distance measures by year. The results of this research suggest that the distance DC PWID traveled to access SEP services remained relatively constant (approximately 2.75 mi) from 2003 to 2008, but increased to just over 4 mi in 2010. This research provides support for expanding SEP operations such that PWID have increased access to their services. Increasing SEP accessibility may help resolve unmet needs among injectors

Assessing seasonality of travel distance to harm reduction service providers among persons who inject drugs.

BACKGROUND: Prior research has examined access to syringe exchange program (SEP) services among persons who inject drugs (PWID), but no research has been conducted to evaluate variations in SEP access based on season. This is an important gap in the literature given that seasonal weather patterns and inclement weather may affect SEP service utilization. The purpose of this research is to examine differences in access to SEPs by season among PWID in the District of Columbia (DC). FINDINGS: A geometric point distance estimation technique was applied to records from a DC SEP that operated from 1996 to 2011. We calculated the walking distance (via sidewalks) from the centroid point of zip code of home residence to the exchange site where PWID presented for services. Analysis of variance (ANOVA) was used to examine differences in walking distance measures by season. Differences in mean walking distance measures were statistically significant between winter and spring with PWID traveling approximately 2.88 and 2.77 miles, respectively, to access the SEP during these seasons. CONCLUSIONS: The results of this study suggest that seasonal differences in SEP accessibility may exist between winter and spring. PWID may benefit from harm reduction providers adapting their SEP operations to provide a greater diversity of exchange locations during seasons in which inclement weather may negatively influence engagement with SEPs. Increasing the number of exchange locations based on season may help resolve unmet needs among injectors

Fault Models for Quantum Mechanical Switching Networks

The difference between faults and errors is that, unlike faults, errors can be corrected using control codes. In classical test and verification one develops a test set separating a correct circuit from a circuit containing any considered fault. Classical faults are modelled at the logical level by fault models that act on classical states. The stuck fault model, thought of as a lead connected to a power rail or to a ground, is most typically considered. A classical test set complete for the stuck fault model propagates both binary basis states, 0 and 1, through all nodes in a network and is known to detect many physical faults. A classical test set complete for the stuck fault model allows all circuit nodes to be completely tested and verifies the function of many gates. It is natural to ask if one may adapt any of the known classical methods to test quantum circuits. Of course, classical fault models do not capture all the logical failures found in quantum circuits. The first obstacle faced when using methods from classical test is developing a set of realistic quantum-logical fault models. Developing fault models to abstract the test problem away from the device level motivated our study. Several results are established. First, we describe typical modes of failure present in the physical design of quantum circuits. From this we develop fault models for quantum binary circuits that enable testing at the logical level. The application of these fault models is shown by adapting the classical test set generation technique known as constructing a fault table to generate quantum test sets. A test set developed using this method is shown to detect each of the considered faults.Comment: (almost) Forgotten rewrite from 200

Legal space for syringe exchange programs in hot spots of injection drug use-related crime.

BACKGROUND: Copious evidence indicates that syringe exchange programs (SEPs) are effective structural interventions for HIV prevention among persons who inject drugs (PWID). The efficacy of SEPs in supporting the public health needs of PWID populations is partially dependent on their accessibility and consistent utilization among injectors. Research has shown that SEP access is an important predictor of PWID retention at SEPs, yet policies exist that may limit the geographic areas where SEP operations may legally occur. Since 2000 in the District of Columbia (DC), SEP operations have been subject to the 1000 Foot Rule (§48-1121), a policy that prohibits the distribution of any needle or syringe for the hypodermic injection of any illegal drug in any area of the District of Columbia which is within 1000 feet of a public or private elementary or secondary school (including a public charter school). The 1000 Foot Rule may impede SEP services in areas that are in urgent need for harm reduction services, such as locations where injections are happening in real time or where drugs are purchased or exchanged. We examined the effects of the 1000 Foot Rule on SEP operational space in injection drug use (IDU)-related crime (i.e., heroin possession or distribution) hot spots from 2000 to 2010. METHODS: Data from the DC Metropolitan Police Department were used to identify IDU-related crime hot spots. School operation data were matched to a dataset that described the approximate physical property boundaries of land parcels. A 1000-ft buffer was applied to all school property boundaries. The overlap between the IDU-related crime hot spots and the school buffer zones was calculated by academic year. RESULTS: When overlaying the land space associated with IDU-related crime hot spots on the maps of school boundaries per the 1000-ft buffer zone stipulation, we found that the majority of land space in these locations was ineligible for legal SEP operations. More specifically, the ineligible space in the identified hot spots in each academic year ranged from 51.93 to 88.29 % of the total hot spot area. CONCLUSIONS: The removal of the 1000 Foot Rule could significantly improve the public health of PWID via increased access to harm reduction services. Buffer zone policies that restrict SEP operational space negatively affect the provision of harm reduction services to PWID

A CLOSER LOOK AT SHALE: REPRESENTATIVE ELEMENTARY VOLUME ANALYSIS WITH LABORATORY 3D X-RAY COMPUTED MICROTOMOGRAPHY AND NANOTOMOGRAPHY

ABSTRACT Though naturally occurring in many regions of the world, shale rock microstructure continues to be much of a mystery. Pore sizes may be very small, typically low 100s of nanometers and even below 10s of nanometers. It is thus very important to determine the volume size that must be examined to understand the oil reserves in a macroscopic shale rock formation, as the small features require a very high resolution imaging system, which usually come with limited field of view. This makes precise quantification of the microstructure a daunting challenge, especially when the analysis needs to be performed in 3D to capture the tortuous paths taken by the pores. The introduction of ultra-high resolution imaging systems is now shedding light on the problem, with the commercialization of precise laboratory x-ray imaging tools. Here, a novel suite of x-ray computed tomography systems is shown to provide unique insight into shale microstructure. Large volumes are measured with as high as sub-1 m resolution using laboratory-based x-ray computed microtomography (VersaXRM) to localize regions-of-interest (ROIs) for further higher resolution analysis. A ROI of cubic volume with ~65 m on each side is isolated for precise analysis with a novel laboratorybased x-ray computed nanotomography system (UltraXRM) capable of 50 nm resolution for quantification of porosity within the shale sample. Using the multi-length scale resolution imaging systems described here, a representative elementary volume (REV) quantification has been performed, which identifies ~30 m as the minimum volume that must be considered in order to quantify pores in shale down to 150 nm linear dimensions. Using a 3D field of view capable of sampling ~4 of these REVs, a precise microstructure analysis is carried out, within which further calculations of pore tortuosity and connectivity are demonstrated. The non-destructive nature of x-ray imaging further opens the door to innovative experimentation, such as time-evolution and studies of microstructure response to varying environmental parameters, such as temperature cycling or surfactant treatment

Sex-Specific Clinical Outcomes of the PACT-HF Randomized Trial

BACKGROUND: Transitional care may have different effects in males and females hospitalized for heart failure. We assessed the sex-specific effects of a transitional care model on clinical outcomes following hospitalization for heart failure. METHODS: In this stepped-wedge cluster randomized trial of adults hospitalized for heart failure in Ontario, Canada, 10 hospitals were randomized to a group of transitional care services or usual care. Outcomes in this exploratory analysis were composite all-cause readmission, emergency department visit, or death at 6 months; and composite all-cause readmission or emergency department visit at 6 months. Models were adjusted for stepped-wedge design and patient age. RESULTS: Among 2494 adults, mean (SD) age was 77.7 (12.1) years, and 1258 (50.4%) were female. The first composite outcome occurred in 371 (66.3%) versus 433 (64.1%) males (hazard ratio [HR], 1.04 [95% CI, 0.86-1.26]; P=0.67) and in 326 (59.9%) versus 463 (64.8%) females (HR, 0.83 [95% CI, 0.69-1.01]; P=0.06) in the intervention and usual care groups, respectively (P=0.012 for sex interaction). The second composite outcome occurred in 357 (63.8%) versus 417 (61.7%) males (HR, 1.03 [95% CI, 0.85-1.24]; P=0.76) and 314 (57.7%) versus 450 (63.0%) females (HR, 0.81 [95% CI, 0.67-0.99]; P=0.037) in the intervention and usual care groups, respectively (P=0.024 for sex interaction). The sex differences were driven by a reduction in all-cause emergency department visits among females (HR, 0.66 [95% CI, 0.51-0.87]; P=0.003), but not males (HR, 1.10 [95% CI, 0.85-1.43]; P=0.46), receiving the intervention (P<0.001 for sex interaction). CONCLUSIONS: A transitional care model offered a reduction in all-cause emergency department visits among females but not males following hospitalization for heart failure. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02112227