On the complexity of probabilistic trials for hidden satisfiability problems

What is the minimum amount of information and time needed to solve 2SAT? When the instance is known, it can be solved in polynomial time, but is this also possible without knowing the instance? Bei, Chen and Zhang (STOC '13) considered a model where the input is accessed by proposing possible assignments to a special oracle. This oracle, on encountering some constraint unsatisfied by the proposal, returns only the constraint index. It turns out that, in this model, even 1SAT cannot be solved in polynomial time unless P=NP. Hence, we consider a model in which the input is accessed by proposing probability distributions over assignments to the variables. The oracle then returns the index of the constraint that is most likely to be violated by this distribution. We show that the information obtained this way is sufficient to solve 1SAT in polynomial time, even when the clauses can be repeated. For 2SAT, as long as there are no repeated clauses, in polynomial time we can even learn an equivalent formula for the hidden instance and hence also solve it. Furthermore, we extend these results to the quantum regime. We show that in this setting 1QSAT can be solved in polynomial time up to constant precision, and 2QSAT can be learnt in polynomial time up to inverse polynomial precision.Comment: 24 pages, 2 figures. To appear in the 41st International Symposium on Mathematical Foundations of Computer Scienc

Complexity-theoretic foundations of BosonSampling with a linear number of modes

BosonSampling is the leading candidate for demonstrating quantum computational advantage in photonic systems. While we have recently seen many impressive experimental demonstrations, there is still a formidable distance between the complexity-theoretic hardness arguments and current experiments. One of the largest gaps involves the ratio of photons to modes: all current hardness evidence assumes a "high-mode" regime in which the number of linear optical modes scales at least quadratically in the number of photons. By contrast, current experiments operate in a "low-mode" regime with a linear number of modes. In this paper we bridge this gap, bringing the hardness evidence for the low-mode experiments to the same level as had been previously established for the high-mode regime. This involves proving a new worst-to-average-case reduction for computing the Permanent that is robust to large numbers of row repetitions and also to distributions over matrices with correlated entries.Comment: 26 pages, 3 figures, to appear at QIP 202

A study of laser-engraving surfaces portability on polymer for the automotive industry

International audienceThe automotive industry is facing a multitude of laser-engraving’s technical solutions for decorative application. However, the reproducibility of laser-engraving’s surface results is not guaranteed at that time. A study of transferability of the process was carried out on four different types of laser-engraving machines in order to understand the phenomena involved and to be able to get rid of it. The samples studied consist in industrial reference polymers already used for application of decorative automotive part: Polypropylene (PP), Polymethyl methacrylate (PMMA) and a blend of Acrylonitrile butadiene styrene and polycarbonate (ABS-PC)

Flight of the COVID-19 patient: experience with a Wuhan evacuee: a case report

BACKGROUND: Coronavirus disease 2019, caused by severe acute respiratory syndrome coronavirus 2, was declared a global pandemic by the World Health Organization in March 2020. CASE PRESENTATION: We report a case of a 51-year-old Chinese woman who was evacuated from Wuhan, China and diagnosed with coronavirus disease 2019 infection at a Southern California quarantine facility. Her clinical course was notable for high fevers, night sweats, productive cough, transient leukopenia, lymphopenia, thrombocytopenia, and transaminitis. Evolving hypoxia and infiltrates on chest imaging warranted the trial of an investigational antiviral drug - remdesivir. Our patient recovered and was discharged after 2 weeks of hospitalization. CONCLUSIONS: This case highlights our patient’s clinical course, including diagnostic work-up, medical management, and challenges in defining non-infectivity in a relatively unknown disease

Comparison of Multiplex Gastrointestinal Pathogen Panel and Conventional Stool Testing for Evaluation of Diarrhea in Patients with Inflammatory Bowel Diseases

Background and aimsGastrointestinal pathogen panels (GPPs) are increasingly being used for evaluation of diarrhea. The impact of these tests on patients with inflammatory bowel diseases (IBD) is unknown. We performed a time-interrupted cohort study comparing GPPs and conventional stool evaluation in patients with IBD with diarrhea.MethodsWe included 268 consecutive patients with IBD who underwent GPP (BioFire Diagnostics®) (n = 134) or conventional stool culture and Clostridium difficile polymerase chain reaction testing (n = 134) during suspected IBD flare between 2012 and 2016. Primary outcome was composite of 30-day IBD-related hospitalization, surgery, or emergency department visit; secondary outcome was IBD treatment modification.ResultsOverall, 41/134 (30.6%) patients tested positive on GPP (18 C. difficile, 17 other bacterial infections, and 6 viral pathogens) versus 14/134 patients (10.4%, all C. difficile) testing positive on conventional testing. Rate of IBD treatment modification in response to stool testing was lower in GPP group as compared conventional stool testing group (35.1 vs. 64.2%, p < 0.01). On multivariate analysis, diagnostic evaluation with GPP was associated with three times higher odds of IBD-related hospitalization/surgery/ED visit (95% CI, 1.27-7.14), as compared to conventional stool testing. This negative impact was partly mediated by differences in ordering provider specialty, with non-gastroenterologists more likely to order GPP as compared to gastroenterologists.ConclusionsIn patients with suspected flare of IBD, GPPs have higher pathogen detection rate and lead to lower rate of IBD treatment modification. A diagnostic testing strategy based on GPPs is associated with higher hospital-related healthcare utilization as compared to conventional stool testing, particularly when utilized by non-gastroenterologists

Application of the Canadian C-Spine rule and nexus low criteria and results of cervical spine radiography in emergency condition

Introduction: the Canadian C Spine Rule (CCR) and the National Emergency X-Radiography Utilization Study (Nexus) low criteria are well accepted as guide to help physician in case of cervical blunt trauma. Methods: we aimed to evaluate retrospectively the application of these recommendations in our emergency department. Secondly we analyzed the quality of cervical spine radiography (CSR) in an emergency setting. Results: 281 patients with cervical blunt trauma were analyzed retrospectively. The CCR and the NEXUS rules were respected in 91.2% and 96.8% of cases respectively. No lesions were found in 96.4% of patient. A lesion was present in 1.1% of patient and suspected in 2.5% of patient. The quality of CSR was adequate in only 37.7% of patient. The poor quality of CSR was due either to the lack of C7 vertebrae visualization in 64.6% or other lower vertebrae in 28%. Other causes included the absence of open mouth view (8%), the absence C1 vertebrae visualization (3.4%), artifact in 2.3% and the absence of lateral view in 0.6% of patient. Conclusion: CCR and NEXUS are widely used in our emergency department. The high rate of inadequate CSR reinforces the debate about it’s utility in emergency condition

The Medical Duty Officer: An Attempt to Mitigate the Ambulance At-Hospital Interval

Introduction: A lack of coordination between emergency medical services (EMS), emergency departments (ED) and systemwide management has contributed to extended ambulance at-hospital times at local EDs. In an effort to improve communication within the local EMS system, the Baltimore City Fire Department (BCFD) placed a medical duty officer (MDO) in the fire communications bureau. It was hypothesized that any real-time intervention suggested by the MDO would be manifested in a decrease in the EMS at-hospital time.Methods: The MDO was implemented on November 11, 2013. A senior EMS paramedic was assigned to the position and was placed in the fire communication bureau from 9 a.m. to 9 p.m., seven days a week. We defined the pre-intervention period as August 2013 - October 2013 and the post-intervention period as December 2013 - February 2014. We also compared the post-intervention period to the “seasonal match control” one year earlier to adjust for seasonal variation in EMS volume. The MDO was tasked with the prospective management of city EMS resources through intensive monitoring of unit availability and hospital ED traffic. The MDO could suggest alternative transport destinations in the event of ED crowding. We collected and analyzed data from BCFD computer-aided dispatch (CAD) system for the following: ambulance response times, ambulance at-hospital interval, hospital diversion and alert status, and “suppression wait time” (defined as the total time suppression units remained on scene until ambulance arrival). The data analysis used a pre/post intervention design to examine the MDO impact on the BCFD EMS system.Results: There were a total of 15,567 EMS calls during the pre-intervention period, 13,921 in the post-intervention period and 14,699 in the seasonal match control period one year earlier. The average at-hospital time decreased by 1.35 minutes from pre- to post-intervention periods and 4.53 minutes from the pre- to seasonal match control, representing a statistically significant decrease in this interval. There was also a statistically significant decrease in hospital alert time (approximately 1,700 hour decrease pre- to post-intervention periods) and suppression wait time (less than one minute decrease from pre- to post- and pre- to seasonal match control periods). The decrease in ambulance response time was not statistically significant.Conclusion: Proactive deployment of a designated MDO was associated with a small, contemporaneous reduction in at-hospital time within an urban EMS jurisdiction. This project emphasized the importance of better communication between EMS systems and area hospitals as well as uniform reporting of variables for future iterations of this and similar projects. [West J Emerg Med. 2016;17(5)662-668.]