1,233 research outputs found

    The Complexity of Bipartite Gaussian Boson Sampling

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    Gaussian boson sampling is a model of photonic quantum computing that has attracted attention as a platform for building quantum devices capable of performing tasks that are out of reach for classical devices. There is therefore significant interest, from the perspective of computational complexity theory, in solidifying the mathematical foundation for the hardness of simulating these devices. We show that, under the standard Anti-Concentration and Permanent-of-Gaussians conjectures, there is no efficient classical algorithm to sample from ideal Gaussian boson sampling distributions (even approximately) unless the polynomial hierarchy collapses. The hardness proof holds in the regime where the number of modes scales quadratically with the number of photons, a setting in which hardness was widely believed to hold but that nevertheless had no definitive proof. Crucial to the proof is a new method for programming a Gaussian boson sampling device so that the output probabilities are proportional to the permanents of submatrices of an arbitrary matrix. This technique is a generalization of Scattershot BosonSampling that we call BipartiteGBS. We also make progress towards the goal of proving hardness in the regime where there are fewer than quadratically more modes than photons (i.e., the high-collision regime) by showing that the ability to approximate permanents of matrices with repeated rows/columns confers the ability to approximate permanents of matrices with no repetitions. The reduction suffices to prove that GBS is hard in the constant-collision regime.Comment: 44 pages; v3 - journal versio

    Does Eating Slowly Influence Appetite and Energy Intake when Water Intake is Controlled?

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    Background: Slow eating has been associated with enhanced satiation, but also with increased water intake. Therefore, the role of water ingestion in regard to eating rate needs to be discerned. This study examined the influence of eating rate on appetite regulation and energy intake when water intake is controlled. Methods: In a randomized design, slow and fast eating rates were compared on two occasions, in 30 women (22.7±1.2y; BMI=22.4±0.4kg/m2) who consumed an ad libitum mixed-macronutrient lunch with water (300 mL). Satiation was examined as the main outcome by measuring energy intake during meals. At designated times, subjects rated hunger, satiety, desire-to-eat, thirst, and meal palatability on visual analogue scales. Paired t-tests were used to compare hypothesis-driven outcomes. Appetite ratings were compared across time points and conditions by repeated measures analysis of variance (ANOVA) using a within-subject model. Results: Energy intake and appetite ratings did not differ between conditions at meal completion. However, subjects rated less hunger and tended to rate lower desire-to-eat and greater satiety at 1 hour following the slow condition. Conclusions: Results tend to support a role of slow eating on decreased hunger and higher inter-meal satiety when water intake is controlled. However, the lack of significant differences in energy intake under these conditions indicates that water intake may account for the effects of eating rate on appetite regulation

    Exploring the latent trait of opioid use disorder criteria among frequent nonmedical prescription opioid users

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    Background: There is a need to explore the dimensional and categorical phenotypes of criteria of opioid use disorder among frequent nonmedical users of prescription opioids (NMUPO) users. Methods: We used pooled data of 2011–2012 National Survey on Drug Use and Health to examine reliability and phenotypic variability in the diagnosis of OUD secondary to NMUPO in a nationally-representative sample of 18+ years-old frequent past-year NMUPO users (120+ days, n = 806). Through exploratory factor analysis (EFA) and latent class analysis (LCA), we examined 10 past-year OUD criteria. We examined associations between the latent classes and sociodemographic/psychiatric/NMUPO correlates. Results: OUD criteria were unidimensional, and a three-class model was the overall best fitting solution for characterizing individuals into phenotypes along this unidimensional continuum: a “non-symptomatic class” (40.7%), “Tolerance-Time spent class” (29.0%) with high probability of endorsing Tolerance/Time Spent criteria, and a “High-moderate symptomatic class” (30.1%). The last class was significantly associated with being male, having insurance and obtaining prescription opioids (PO) nonmedically via “doctor shopping” as compared to the non-symptomatic class. “Tolerance-Time spent class” was significantly associated with being younger (18–25 years) and obtaining PO nonmedically from family/friends as compared to the non-symptomatic class. Conclusion: This study revealed the different characteristics and routes of access to PO of different classes of frequent NMUPO users. It is possible that these groups may respond to different interventions, however such conclusions would require a clinical study

    The liver transcriptome of suckermouth armoured catfish (Pterygoplichthys anisitsi, Loricariidae) : identification of expansions in defensome gene families

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    © The Author(s), 2016. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Marine Pollution Bulletin 115 (2017): 352-361, doi:10.1016/j.marpolbul.2016.12.012.Pterygoplichthys is a genus of related suckermouth armoured catfish native to South America that has invaded tropical and subtropical regions worldwide. Physiological features, including an augmented resistance to organic xenobiotics, may have aided their settlement in foreign habitats. The liver transcriptome of Pterygoplichthys anisitsi was sequenced and used to characterize the diversity of mRNAs potentially involved in the responses to natural and anthropogenic chemicals. In total, 66,642 transcripts were assembled. Among the identified defensome genes, cytochromes P450 (CYP) were the most abundant, followed by nuclear receptors (NR), sulfotransferases (SULT) and ATP binding cassette transporters (ABC). A novel expansion in the CYP2Y subfamily was identified, as well as an independent expansion of the CYP2AAs. Two expansions were also observed among SULT1. Thirty-nine transcripts were classified into twelve subfamilies of NR, while 21 encoded ABC transporters. The diversity of defensome transcripts sequenced herein could contribute to this species resistance to organic xenobiotics.This study was supported by a PEER grant from USAID (PGA-2000003446 and PGA-2000004790) associated with NSF grant DEB-1120263. T.E.P, D.A.M, and M.G.P.M receives independent fellowships from the Brazilian funding agency CAPES

    Crystal Field Triplets: A New Route to Non-Fermi Liquid Physics

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    A model for crystal field triplet ground states on rare earth or actinide ions with dipolar and quadrupolar couplings to conduction electrons is studied for the first time with renormalization group methods. The quadrupolar coupling leads to a new nontrivial, non-Fermi liquid fixed point, which survives in an intermediate valence Anderson model. The calculated magnetic susceptibility displays one parameter scaling, going as TαT^{-\alpha} (α0.4\alpha \approx 0.4) at intermediate temperatures, reminiscent of the non-Fermi liquid alloy UCu_{5-x}Pd_x.Comment: 4 pages, 3 figures, REVTe

    Methadone in post-herpetic neuralgia: A pilot proof-of-concept study

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    OBJECTIVE: This research was designed as a pilot proof-of-concept study to evaluate the use of low-dose methadone in post-herpetic neuralgia patients who remained refractory after first and second line post-herpetic neuralgia treatments and had indications for adding an opioid agent to their current drug regimens. METHODS: This cross-over study was double blind and placebo controlled. Ten opioid naïve post-herpetic neuralgia patients received either methadone (5 mg bid) or placebo for three weeks, followed by a 15-day washout period and a second three-week treatment with either methadone or placebo, accordingly. Clinical evaluations were performed four times (before and after each three-week treatment period). The evaluations included the visual analogue scale, verbal category scale, daily activities scale, McGill pain questionnaire, adverse events profile, and evoked pain assessment. All patients provided written informed consent before being included in the study. ClinicalTrials.gov: NCT01752699 RESULTS: Methadone, when compared to placebo, did not significantly affect the intensity of spontaneous pain, as measured by the visual analogue scale. The intensity of spontaneous pain was significantly decreased after the methadone treatment compared to placebo on the category verbal scale (50% improved after the methadone treatment, none after the placebo, p = 0.031). Evoked pain was reduced under methadone compared to placebo (50% improved after the methadone treatment, none after the placebo, p = 0.031). Allodynia reduction correlated with sleep improvement (r = 0.67, p = 0.030) during the methadone treatment. The side effects profile was similar between both treatments. Conclusions: Methadone seems to be safe and efficacious in post-herpetic neuralgia. It should be tried as an adjunctive treatment for post-herpetic neuralgia in larger prospective studies

    Can predatory mites aid in the management of the citrus leprosis mite?

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    IntroductionThe flat mite Brevipalpus yothersi is the main vector of citrus leprosis in South and Central America and Mexico, where vector suppression using conventional acaricides is usually the only disease control method, leading to problems with acaricide resistance. This mite is present in Florida, where several viruses known to cause citrus leprosis were recently detected. This research builds preparedness for managing emerging viral diseases and mitigating potential problems associated with acaricide resistance by addressing the compatibility of chemical and biological control strategies against B. yothersi. The predatory mite Amblyseius largoensis has shown promise as a biological control agent of B. yothersi. However, the effects of acaricides used in citrus on this predator are unknown.MethodsThis study investigated the impact of different routes of acaricide exposure on A. largoensis, including direct contact, pesticide-contaminated prey, residual contact, and combined exposure routes in laboratory settings. Additionally, the efficacy of A. largoensis in controlling B. yothersi, alone and in combination with acaricide applications, was evaluated under greenhouse conditions.Results and discussionCommonly used acaricides like abamectin and spirodiclofen were highly effective in controlling B. yothersi and only slightly harmful to A. largoensis. Other acaricides were also effective against B. yothersi but were less compatible with the predatory mite. In the greenhouse trial, all acaricides, alone or in combination with the predators, and the predators alone, effectively suppressed B. yothersi one month after treatment application. However, B. yothersi populations significantly increased one month later in the abamectin-alone and predator-alone treatments. At the same time, the combination of abamectin and predators provided B. yothersi suppression throughout the experiment. The fenpyroximate-predator combination also provided better control than each treatment applied independently. All other acaricides provided prolonged B. yothersi control, hindering biological control probably due to the lack of prey for A. largoensis. Research findings highlight the potential for enhancing the selectivity of acaricides towards A. largoensis by manipulating their exposure route. Combining predatory mites with acaricides shows promise in improving B. yothersi management
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