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

A Phase I Dose Escalation Trial of Gemcitabine with Radiotherapy for Breast Cancer in the Treatment of Unresectable Chest Wall Recurrences

The purpose of this study was to determine the maximum tolerated dose (MTD) of gemcitabine when given concurrently with standard radiotherapy for the treatment of chest wall recurrences, and to compare actuarial rates of local-regional control with those achieved in historical controls. Patients with unresectable chest wall recurrences were enrolled in a phase I trial of concurrent gemcitabine and radiotherapy. Gemcitabine was increased at 150 mg/m 2 /week increments, starting at 300 mg/m 2 /week. Radiotherapy was delivered to the chest wall and regional nodes to a total of 60 to 70 Gy in 2 Gy daily fractions. Treatment toxicity was assessed and a comparison of treatment outcome was performed between study patients and historical groups treated with either radiotherapy alone or excision followed by radiotherapy. The dose-limiting toxicities of neutropenia and thrombocytopenia occurred at the second planned dose of 450 mg/m 2 /week after accrual of only six patients, resulting in a MTD of 300 mg/m 2 /week. Myelosuppression and skin desquamation were commonly observed. Actuarial rates of local-regional control were 100%, 50%, and 90% at 2 years for the gemcitabine with radiotherapy, radiotherapy alone, and excision followed by radiotherapy groups, respectively ( p  = 0.105). The difference among the Kaplan–Meier curves for overall local-regional control was statistically significant at p  = 0.007 in favor of combined gemcitabine and radiotherapy. The MTD of gemcitabine is 300 mg/m 2 /week when gemcitabine is delivered concurrently with radiotherapy for unresectable chest wall failures. This novel approach suggests excellent local-regional control when compared to historical controls. A phase II trial is warranted. Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75565/1/j.1075-122X.2004.21305.x.pd

Business development in renewable energy

This paper discusses how to foster development of renewable energy business. Factors that impede or enhance renewable energy in the EU 27 member states in the period 1998–2008 are analyzed. Nine factors are considered: population density, production output and energy sector output to indicate market conditions, public total expenditures, subsidies and environmental protection expenditures to indicate institutional conditions, R&D, share of students in population and venture capital to indicate firm’s resources. Scarce space for business development and vested energy interests are the main impediments. R&D and venture capital are main drivers. The US and EU support for R&D and venture capital in renewable energy are compared. The US support is larger and mainly based on R&D grants. It has generated large, innovative enterprises. The EU support is mainly based on price guarantees for renewable energy delivery to grid. It has generated many enterprises. Building capabilities through stakeholders’ networks in early phase of business development and clusters in the later phase is recommended

The management of patients with primary chronic anal fissure: a position paper

Anal fissure is one of the most common and painful proctologic diseases. Its treatment has long been discussed and several different therapeutic options have been proposed. In the last decades, the understanding of its pathophysiology has led to a progressive reduction of invasive and potentially invalidating treatments in favor of conservative treatment based on anal sphincter muscle relaxation. Despite some systematic reviews and an American position statement, there is ongoing debate about the best treatment for anal fissure. This review is aimed at identifying the best treatment option drawing on evidence-based medicine and on the expert advice of 6 colorectal surgeons with extensive experience in this field in order to produce an Italian position statement for anal fissures. While there is little chance of a cure with conservative behavioral therapy, medical treatment with calcium channel blockers, diltiazem and nifepidine or glyceryl trinitrate, had a considerable success rate ranging from 50 to 90%. Use of 0.4% glyceryl trinitrate in standardized fashion seems to have the best results despite a higher percentage of headache, while the use of botulinum toxin had inconsistent results. Nonresponding patients should undergo lateral internal sphincterotomy. The risk of incontinence after this procedure seems to have been overemphasized in the past. Only a carefully selected group of patients, without anal hypertonia, could benefit from anoplasty

Botulinum toxin injection versus lateral internal sphincterotomy in the treatment of chronic anal fissure: a non-randomized controlled trial

BACKGROUND: Although lateral internal sphincterotomy is the gold-standard treatment for chronic anal fissure, intrasphincteric injection of botulinum toxin seems to be a reliable new option. The aim of this non-randomized study is to compare the effect of lateral internal sphincterotomy and botulinum toxin injection treatments on the outcome and reduction of anal sphincter pressures in patients with chronic anal fissure. METHODS: Patients with chronic anal fissure were treated with either botulinum toxin injection or lateral internal sphincterotomy by their own choice. Maximal resting pressure and maximal squeeze pressure measurements were performed before and 2 weeks after treatments by anal manometry. Patients were followed for fissure relapse during 14 months. RESULTS: Twenty-one consecutive outpatients with posterior chronic anal fissure were enrolled. Eleven patients underwent surgery and ten patients received botulinum toxin injection treatment. Before the treatment, anal pressures were found to be similar in both groups. After the treatment, the maximal resting pressures were reduced from 104 ± 22 mmHg to 86 ± 15 mmHg in the surgery group (p < 0.05) and from 101 ± 23 mmHg to 83 ± 24 mmHg in the botulinum toxin group (p < 0.05). The mean maximal squeeze pressures were reduced from 70 ± 27 mmHg to 61 ± 32 mmHg (p > 0.05) in the surgery group, and from 117 ± 62 mmHg to 76 ± 34 (p < 0.01) in the botulinum toxin group. The fissures were healed in 70 percent of patients in the botulinum group and 82 percent in the surgery group (p > 0.05). There were no relapses during the 14 months of follow up. CONCLUSION: Lateral internal sphincterotomy and botulinum toxin injection treatments both seem to be equally effective in the treatment of chronic anal fissure

Phylogeny of Diving Beetles Reveals a Coevolutionary Arms Race between the Sexes

BACKGROUND: Darwin illustrated his sexual selection theory with male and female morphology of diving beetles, but maintained a cooperative view of their interaction. Present theory suggests that instead sexual conflict should be a widespread evolutionary force driving both intersexual coevolutionary arms races and speciation. METHODOLOGY/PRINCIPAL FINDINGS: We combined Bayesian phylogenetics, complete taxon sampling and a multi-gene approach to test the arms race scenario on a robust diving beetle phylogeny. As predicted, suction cups in males and modified dorsal surfaces in females showed a pronounced coevolutionary pattern. The female dorsal modifications impair the attachment ability of male suction cups, but each antagonistic novelty in females corresponds to counter-differentiation of suction cups in males. CONCLUSIONS: A recently diverged sibling species pair in Japan is possibly one consequence of this arms race and we suggest that future studies on hypoxia might reveal the key to the extraordinary selection for female counter-adaptations in diving beetles

Optimal treatment duration of glyceryl trinitrate for chronic anal fissure: results of a prospective randomized multicenter trial

Background: Chronic anal fissure (CAF) is a painful condition that is unlikely to resolve with conventional conservative management. Previous studies have reported that topical treatment of CAF with glyceryl trinitrate (GTN) reduces pain and promotes healing, but optimal treatment duration is unknown. Methods: To assess the effect of different treatment durations on CAF, we designed a prospective randomized trial comparing 40 versus 80 days with twice daily topical 0.4% GTN treatment (Rectogesic®, Prostrakan Group). Chronicity was defined by the presence of both morphological (fibrosis, skin tag, exposed sphincter, hypertrophied anal papilla) and time criteria (symptoms present for more than 2 months or pain of less duration but similar episodes in the past). A gravity score (1 = no visible sphincter; 2 = visible sphincter; 3 = visible sphincter and fibrosis) was used at baseline. Fissure healing, the primary endpoint of the study, maximum pain at defecation measured with VAS and maximum anal resting pressure were assessed at baseline and at 14, 28, 40 and 80 days. Data was gathered at the end of the assigned treatment. Results: Of 188 patients with chronic fissure, 96 were randomized to the 40-day group and 92 to the 80-day group. Patients were well matched for sex, age, VAS and fissure score. There were 34 (19%) patients who did not complete treatment, 18 (10%) because of side effects. Of 154 patients who completed treatment, 90 (58%) had their fissures healed and 105 (68%) were pain free. There was no difference in healing or symptoms between the 40- and the 80-day group. There was no predictor of fissure healing. A low fissure gravity score correlated with increased resolution of pain (P &lt; 0.05) and improvement of VAS score (P &lt; 0.05) on both univariate and multivariate analysis. A lower baseline resting pressure was associated with better pain resolution on univariate analysis (P &lt; 0.01). VAS at defecation and fissure healing significantly improved until 40 days (P &lt; 0.001), while the difference between 40 and 80 days was not significant. Conclusion: We found no benefits in treating CAF with topical GTN for 80 days compared to 40 days. Fissure healing and VAS improvement continue until 6 weeks of treatment but are unlikely thereafter. © 2010 Springer-Verlag

Elevated Cerebral Spinal Fluid Cytokine Levels in Boys with Cerebral Adrenoleukodystrophy Correlates with MRI Severity

Background: X-linked adrenoleukodystrophy (ALD) is a metabolic, peroxisomal disease that results from a mutation in the ABCD1 gene. The most severe course of ALD progression is the cerebral inflammatory and demyelinating form of the disease, cALD. To date there is very little information on the cytokine mediators in the cerebral spinal fluid (CSF) of these boys. Methodology/Principal Findings: Measurement of 23 different cytokines was performed on CSF and serum of boys with cerebral ALD and patients without ALD. Significant elevations in CSF IL-8 (29.362.2 vs 12.861.1 pg/ml, p = 0.0001), IL-1ra (166630 vs 8.666.5 pg/ml, p = 0.005), MCP-1 (610647 vs 328634 pg/ml, p = 0.002), and MIP-1b (14.261.3 vs 2.061.4 pg/ml, p,0.0001) were found in boys with cALD versus the control group. The only serum cytokine showing an elevation in the ALD group was SDF-1 (21246155 vs 11756125 pg/ml, p = 0.0001). The CSF cytokines of IL-8 and MCP-1b correlated with the Loes MRI severity score (p = 0.04 and p = 0.008 respectively), as well as the serum SDF-1 level (p = 0.002). Finally, CSF total protein was also significantly elevated in boys with cALD and correlated with both IL-8, MCP-1b (p = 0.0001 for both), as well as Loes MRI severity score (p = 0.0007). Conclusions/Significance: IL-8, IL-1ra, MCP-1, MIP-1b and CSF total protein were significantly elevated in patients with cALD; IL-8, MCP-1b, and CSF total protein levels correlated with disease severity determined by MRI. This is the largest repor

A search for the decay modes B+/- to h+/- tau l

We present a search for the lepton flavor violating decay modes B+/- to h+/- tau l (h= K,pi; l= e,mu) using the BaBar data sample, which corresponds to 472 million BBbar pairs. The search uses events where one B meson is fully reconstructed in one of several hadronic final states. Using the momenta of the reconstructed B, h, and l candidates, we are able to fully determine the tau four-momentum. The resulting tau candidate mass is our main discriminant against combinatorial background. We see no evidence for B+/- to h+/- tau l decays and set a 90% confidence level upper limit on each branching fraction at the level of a few times 10^-5.Comment: 15 pages, 7 figures, submitted to Phys. Rev.

Evidence for an excess of B -> D(*) Tau Nu decays

Based on the full BaBar data sample, we report improved measurements of the ratios R(D(*)) = B(B -> D(*) Tau Nu)/B(B -> D(*) l Nu), where l is either e or mu. These ratios are sensitive to new physics contributions in the form of a charged Higgs boson. We measure R(D) = 0.440 +- 0.058 +- 0.042 and R(D*) = 0.332 +- 0.024 +- 0.018, which exceed the Standard Model expectations by 2.0 sigma and 2.7 sigma, respectively. Taken together, our results disagree with these expectations at the 3.4 sigma level. This excess cannot be explained by a charged Higgs boson in the type II two-Higgs-doublet model. We also report the observation of the decay B -> D Tau Nu, with a significance of 6.8 sigma.Comment: Expanded section on systematics, text corrections, improved the format of Figure 2 and included the effect of the change of the Tau polarization due to the charged Higg