No imminent quantum supremacy by boson sampling

It is predicted that quantum computers will dramatically outperform their conventional counterparts. However, large-scale universal quantum computers are yet to be built. Boson sampling is a rudimentary quantum algorithm tailored to the platform of photons in linear optics, which has sparked interest as a rapid way to demonstrate this quantum supremacy. Photon statistics are governed by intractable matrix functions known as permanents, which suggests that sampling from the distribution obtained by injecting photons into a linear-optical network could be solved more quickly by a photonic experiment than by a classical computer. The contrast between the apparently awesome challenge faced by any classical sampling algorithm and the apparently near-term experimental resources required for a large boson sampling experiment has raised expectations that quantum supremacy by boson sampling is on the horizon. Here we present classical boson sampling algorithms and theoretical analyses of prospects for scaling boson sampling experiments, showing that near-term quantum supremacy via boson sampling is unlikely. While the largest boson sampling experiments reported so far are with 5 photons, our classical algorithm, based on Metropolised independence sampling (MIS), allowed the boson sampling problem to be solved for 30 photons with standard computing hardware. We argue that the impact of experimental photon losses means that demonstrating quantum supremacy by boson sampling would require a step change in technology.Comment: 25 pages, 9 figures. Comments welcom

Total Laparoscopic Restorative Proctocolectomy: Are There Advantages Compared with the Open and Hand-Assisted Approaches?

PURPOSE: A randomized, controlled trial comparing hand-assisted laparoscopic restorative proctocolectomy with open surgery did not show an advantage for the laparoscopic approach. The trial was criticized because hand-assisted laparoscopic restorative proctocolectomy was not considered a true laparoscopic proctocolectomy. The objective of the present study was to assess whether total laparoscopic restorative proctocolectomy has advantages over hand-assisted laparoscopic restorative proctocolectomy with respect to early recovery. METHODS: Thirty-five patients underwent total laparoscopic restorative proctocolectomy and were compared to 60 patients from a previously conducted randomized, controlled trial comparing hand-assisted laparoscopic restorative proctocolectomy and open restorative proctocolectomy. End points included operating time, conversion rate, reoperation rate, hospital stay, morbidity, quality of life, and costs. The Medical Outcomes Study Short Form 36 and the Gastrointestinal Quality of Life Index were used to evaluate general and bowel-related quality of life. RESULTS: Groups were comparable for patient characteristics, such as sex, body mass index, preoperative disease duration, and age. There were neither conversions nor intraoperative complications. Median operating time was longer in the total laparoscopic compared with the hand-assisted laparoscopic group (298 vs. 214 minutes; P < 0.001). Morbidity and reoperation rates in the total laparoscopic, hand-assisted laparoscopic, and open groups were comparable (29 vs. 20 vs. 23 percent and 17 vs.10 vs. 13 percent, respectively). Median hospital-stay was 9 days in the total laparoscopic group compared with 10 days in the hand-assisted laparoscopic group and 11 days in the open group (P = not significant). There were no differences in quality of life and total costs. CONCLUSIONS: There were no significant short-term benefits for total laparoscopic compared with hand-assisted laparoscopic restorative proctocolectomy with respect to early morbidity, operating time, quality of life, costs, and hospital sta

Implications of sperm banking for health-related quality of life up to 1 year after cancer diagnosis.

Sperm banking is recommended for all men diagnosed with cancer where treatment is associated with risk of long-term gonadatoxicity, to offer the opportunity of fatherhood and improved quality of life. However, uptake of sperm banking is lower than expected and little is known about why men refuse. Our aims were to determine: (i) demographic and medical variables associated with decisions about banking and (ii) differences in quality of life between bankers and non-bankers at diagnosis (Time 1 (T1)) and 1 year later (Time 2 (T2))

Vascular time-activity variation in patients undergoing 123I-MIBG myocardial scintigraphy: implications for quantification of cardiac and mediastinal uptake

For the quantification of cardiac (123)I-metaiodobenzylguanidine (MIBG) uptake, the mediastinum is commonly used as a reference region reflecting nonspecific background activity. However, variations in the quantity of vascular structures in the mediastinum and the rate of renal clearance of (123)I-MIBG from the blood pool may contribute to increased interindividual variation in uptake. This study examined the relationship between changes in heart (H) and mediastinal (M) counts and the change in vascular (123)I-MIBG activity, including the effect of renal function. Fifty-one subjects with ischemic heart disease underwent early (15 min) and late (4 h) anterior planar images of the chest following injection of (123)I-MIBG. Vascular (123)I-MIBG activity was determined from venous blood samples obtained at 2 min, 15 min, 35 min, and 4 h post-injection. From the vascular clearance curve of each subject, the mean blood counts/min per ml at the time of each acquisition and the slope of the clearance curve were determined. Renal function was expressed as the estimated creatinine clearance (e-CC) and the estimated glomerular filtration rate (e-GFR). Relations between H and M region of interest (ROI) counts/pixel, vascular activity, and renal function were then examined using linear regression. Changes in ROI activity ratios between early and late planar images could not be explained by blood activity, the slope of the vascular clearance curves, or estimates of renal function. At most 3% of the variation in image counts could be explained by changes in vascular activity (p = 0.104). The e-CC and e-GFR could at best explain approximately 1.5% of the variation in the slopes of the vascular clearance curve (p = 0.194). The change in measured H and M counts between early and late planar (123)I-MIBG images is unrelated to intravascular levels of the radiopharmaceutical. This suggests that changes in M counts are primarily due to decrease in soft tissue activity and scatter from the adjacent lung

Simultaneous in-field boost for patients with 1 to 4 brain metastasis/es treated with volumetric modulated arc therapy: a prospective study on quality-of-life

<p>Abstract</p> <p>Purpose</p> <p>To assess treatment toxicity and patients' survival/quality of life (QoL) after volumetric modulated arc therapy (VMAT) with simultaneous in-field boost (SIB) for cancer patients with 1 - 4 brain metastases (BM) treated with or without surgery.</p> <p>Methods and Materials</p> <p>Between March and December 2010, 29 BM patients (total volume BM, < 40 cm³) aged < 80 years, KPS ≥ 70, RPA < III were included in this prospective trial. Whole brain VMAT (30 Gy) and a SIB to the BM (40 Gy) was delivered in 10 fraction. Mean age was 62.1 ± 8.5 years. Fifteen (51.7%) underwent surgery. KPS and MMSE were prospectively assessed. A self-assessed questionnaire was used to assess the QoL (EORTC QLQ-C30 with -BN20 module).</p> <p>Results</p> <p>As of April 2011 and after a mean FU of 5.4 ± 2.8 months, 14 (48.3%) patients died. The 6-month overall survival was 55.1%. Alopecia was only observed in 9 (31%) patients. In 3-month survivors, KPS was significantly (<it>p </it>= 0.01) decreased. MMSE score remained however stable (<it>p </it>= 0.33). Overall, QoL did decrease after VMAT. The mean QLQ-C30 global health status (<it>p </it>= 0.72) and emotional functional (<it>p </it>= 0.91) scores were decreased (low QoL). Physical (<it>p </it>= 0.05) and role functioning score (<it>p </it>= 0.01) were significantly worse and rapidly decreased during treatment. The majority of BN20 domains and single items worsened 3 months after VMAT except headaches (<it>p </it>= 0.046) and bladder control (<it>p </it>= 0.26) which improved.</p> <p>Conclusions</p> <p>The delivery of 40 Gy in 10 fractions to 1 - 4 BM using VMAT was achieved with no significant toxicity. QoL, performance status, but not MMSE, was however compromised 3 months after treatment in this selected cohort of BM patients.</p

Outcomes of patients hospitalized for acute decompensated heart failure: does nesiritide make a difference?

<p>Abstract</p> <p>Background</p> <p>Nesiritide is indicated in the treatment of acute decompensated heart failure. However, a recent meta-analysis reported that nesiritide may be associated with an increased risk of death. Our goal was to evaluate the impact of nesiritide treatment on four outcomes among adults hospitalized for congestive heart failure (CHF) during a three-year period.</p> <p>Methods</p> <p>CHF patients discharged between 1/1/2002 and 12/31/2004 from the Adventist Health System, a national, not-for-profit hospital system, were identified. 25,330 records were included in this retrospective study. Nesiritide odds ratios (OR) were adjusted for various factors including nine medications and/or an APR-DRG severity score.</p> <p>Results</p> <p>Initially, treatment with nesiritide was found to be associated with a 59% higher odds of hospital mortality (Unadjusted OR = 1.59, 95% confidence interval [CI]: 1.31–1.93). Adjusting for race, low economic status, APR-DRG severity of illness score, and the receipt of nine medications yielded a nonsignificant nesiritide OR of 1.07 for hospital death (95% CI: 0.85–1.35). Nesiritide was positively associated with the odds of prolonged length of stay (all adjusted ORs = 1.66) and elevated pharmacy cost (all adjusted ORs > 5).</p> <p>Conclusion</p> <p>In this observational study, nesiritide therapy was associated with increased length of stay and pharmacy cost, but not hospital mortality. Randomized trials are urgently needed to better define the efficacy, if any, of nesiritide in the treatment of decompensated heart failure.</p

Effects of Interferon-α/β on HBV Replication Determined by Viral Load

Interferons α and β (IFN-α/β) are type I interferons produced by the host to control microbial infections. However, the use of IFN-α to treat hepatitis B virus (HBV) patients generated sustained response to only a minority of patients. By using HBV transgenic mice as a model and by using hydrodynamic injection to introduce HBV DNA into the mouse liver, we studied the effect of IFN-α/β on HBV in vivo. Interestingly, our results indicated that IFN-α/β could have opposite effects on HBV: they suppressed HBV replication when viral load was high and enhanced HBV replication when viral load was low. IFN-α/β apparently suppressed HBV replication via transcriptional and post-transcriptional regulations. In contrast, IFN-α/β enhanced viral replication by inducing the transcription factor HNF3γ and activating STAT3, which together stimulated HBV gene expression and replication. Further studies revealed an important role of IFN-α/β in stimulating viral growth and prolonging viremia when viral load is low. This use of an innate immune response to enhance its replication and persistence may represent a novel strategy that HBV uses to enhance its growth and spread in the early stage of viral infection when the viral level is low

Functional health status in subjects after a motor vehicle accident, with emphasis on whiplash associated disorders: design of a descriptive, prospective inception cohort study

Contains fulltext : 70254.pdf (publisher's version ) (Open Access)BACKGROUND: The clinical consequences of whiplash injuries resulting from a motor vehicle accident (MVA) are poorly understood. Thereby, there is general lack of research on the development of disability in patients with acute and chronic Whiplash Associated Disorders. METHODS/DESIGN: The objective is to describe the design of an inception cohort study with a 1-year follow-up to determine risk factors for the development of symptoms after a low-impact motor vehicle accident, the prognosis of chronic disability, and costs. Victims of a low-impact motor vehicle accident will be eligible for participation. Participants with a Neck Disability Index (NDI) score of 7 or more will be classified as experiencing post-traumatic neck pain and will enter the experimental group. Participants without complaints (a NDI score less than 7) will enter the reference group. The cohort will be followed up by means of postal questionnaires and physical examinations at baseline, 3 months, 6 months, and 12 months. Recovery from whiplash-associated disorders will be measured in terms of perceived functional health, and employment status (return to work). Life tables will be generated to determine the 1-year prognosis of whiplash-associated disorders, and risk factors and prognostic factors will be assessed using multiple logistic regression analysis. DISCUSSION: Little is known about the development of symptoms and chronic disability after a whiplash injury. In the clinical setting, it is important to identify those people who are at risk of developing chronic symptoms.This inception prospective cohort study will provide insight in the influence of risk factors, of the development of functional health problems, and costs in people with whiplash-associated disorders

Computers in the Exam Room: Differences in Physician–Patient Interaction May Be Due to Physician Experience

BACKGROUND: The use of electronic medical records can improve the technical quality of care, but requires a computer in the exam room. This could adversely affect interpersonal aspects of care, particularly when physicians are inexperienced users of exam room computers. OBJECTIVE: To determine whether physician experience modifies the impact of exam room computers on the physician–patient interaction. DESIGN: Cross-sectional surveys of patients and physicians. SETTING AND PARTICIPANTS: One hundred fifty five adults seen for scheduled visits by 11 faculty internists and 12 internal medicine residents in a VA primary care clinic. MEASUREMENTS: Physician and patient assessment of the effect of the computer on the clinical encounter. MAIN RESULTS: Patients seeing residents, compared to those seeing faculty, were more likely to agree that the computer adversely affected the amount of time the physician spent talking to (34% vs 15%, P = 0.01), looking at (45% vs 24%, P = 0.02), and examining them (32% vs 13%, P = 0.009). Moreover, they were more likely to agree that the computer made the visit feel less personal (20% vs 5%, P = 0.017). Few patients thought the computer interfered with their relationship with their physicians (8% vs 8%). Residents were more likely than faculty to report these same adverse effects, but these differences were smaller and not statistically significant. CONCLUSION: Patients seen by residents more often agreed that exam room computers decreased the amount of interpersonal contact. More research is needed to elucidate key tasks and behaviors that facilitate doctor–patient communication in such a setting

Randomized double-blind placebo-controlled trial of sublingual immunotherapy in children with house dust mite allergy in primary care: study design and recruitment

Background. For respiratory allergic disorders in children, sublingual immunotherapy has been developed as an alternative to subcutaneous immunotherapy. Sublingual immunotherapy is more convenient, has a good safety profile and might be an attractive option for use in primary care. A randomized double-blind placebo-controlled study was designed to establish the ef