1,612 research outputs found
Controlled Heterogeneous Nucleation and Growth of Germanium Quantum Dots on Nanopatterned Silicon Dioxide and Silicon Nitride Substrates
Controlled heterogeneous nucleation and growth of Ge quantum dots (QDs) are demonstrated on SiO_2/Si_3N_4 substrates by means of a novel fabrication process of thermally oxidizing nanopatterned SiGe layers. The otherwise random self-assembly process for QDs is shown to be strongly influenced by the nanopatterning in determining both the location and size of the QDs. Ostwald ripening processes are observed under further annealing at the oxidation temperature. Both nanopattern oxidation and Ostwald ripening offer additional mechanisms for lithography for controlling the size and placement of the QDs
The impact of anti-diabetic drugs on colorectal cancer risk in a large cohort of women with diabetes
No Abstrac
Linear Insertion Deletion Codes in the High-Noise and High-Rate Regimes
This work continues the study of linear error correcting codes against adversarial insertion deletion errors (insdel errors). Previously, the work of Cheng, Guruswami, Haeupler, and Li [Kuan Cheng et al., 2021] showed the existence of asymptotically good linear insdel codes that can correct arbitrarily close to 1 fraction of errors over some constant size alphabet, or achieve rate arbitrarily close to 1/2 even over the binary alphabet. As shown in [Kuan Cheng et al., 2021], these bounds are also the best possible. However, known explicit constructions in [Kuan Cheng et al., 2021], and subsequent improved constructions by Con, Shpilka, and Tamo [Con et al., 2022] all fall short of meeting these bounds. Over any constant size alphabet, they can only achieve rate < 1/8 or correct < 1/4 fraction of errors; over the binary alphabet, they can only achieve rate < 1/1216 or correct < 1/54 fraction of errors. Apparently, previous techniques face inherent barriers to achieve rate better than 1/4 or correct more than 1/2 fraction of errors.
In this work we give new constructions of such codes that meet these bounds, namely, asymptotically good linear insdel codes that can correct arbitrarily close to 1 fraction of errors over some constant size alphabet, and binary asymptotically good linear insdel codes that can achieve rate arbitrarily close to 1/2. All our constructions are efficiently encodable and decodable. Our constructions are based on a novel approach of code concatenation, which embeds the index information implicitly into codewords. This significantly differs from previous techniques and may be of independent interest. Finally, we also prove the existence of linear concatenated insdel codes with parameters that match random linear codes, and propose a conjecture about linear insdel codes
Recommended from our members
Antidopaminergic treatment is associated with reduced chorea and irritability but impaired cognition in Huntington’s disease (Enroll-HD)
Objectives: Alterations in dopamine neurotransmission underlie some of the clinical features of Huntington’s disease (HD) and as such are a target for therapeutic intervention, especially for the treatment of chorea and some behavioural problems. However, justification for such an intervention is mainly based on case reports and small open label studies and the effects these drugs have on cognition in HD remain unclear. Methods: In this study, we used the Enroll-HD observational database to assess the effects of antidopaminergic medication on motor, psychiatric and cognitive decline, over a 3-year period. We first looked at the annual rate of decline of a group of HD patients taking antidopaminergic medication (n=466) compared with an untreated matched group (n=466). The groups were matched on specified clinical variables using propensity score matching. Next, we studied a separate group of HD patients who were prescribed such medications part way through the study (n=90) and compared their rate of change before and after the drugs were introduced and compared this to a matched control group. Results: We found that HD patients taking antidopaminergic medication had a slower progression in chorea and irritability compared with those not taking such medications. However, this same group of patients also displayed significantly greater rate of decline in a range of cognitive tasks. Conclusion: In conclusion we found that antidopaminergic treatment is associated with improvements in the choreic movements and irritability of HD but worsens cognition. However, further research is required to prospectively investigate this and whether these are causally linked, ideally in a double-blind placebo-controlled trial
Effects of Vanadium doping on BaFe2As2
We report an investigation of the structural, magnetic and electronic
properties of Ba(Fe(1-x)V(x))2As2 using x-ray, transport, magnetic
susceptibility and neutron scattering measurements. The vanadium substitutions
in Fe sites are possible up to 40\%. Hall effect measurements indicate strong
hole-doping effect through V doping, while no superconductivity is observed in
all samples down to 2K. The antiferromagnetic and structural transition
temperature of BaFe2As2 is gradually suppressed to finite temperature then
vanishes at x=0.245 with the emergence of spin glass behavior, suggesting an
avoided quantum critical point (QCP). Our results demonstrate that the avoided
QCP and spin glass state which were previously reported in the superconducting
phase of Co/Ni-doped BaFe2As2 can also be realized in non-superconducting
Ba(Fe(1-x)V(x))2As2.Comment: 5 pages, 6 figure
Economic Evaluation of Treating Herpes Zoster with Various Methods of Acupuncture and Moxibustion
AbstractObjectiveTo analyze the cost effect of surrounding acupuncture plus electric acupuncture, cotton-sheet moxibustion, puncturing with red-hot needles, tapping plus cupping on herpes zoster.MethodsFive hundred patients with herpes zoster were randomly divided into group A (surrounding acupuncture plus electric acupuncture), group B (cotton-sheet moxibustion), group C (puncturing with red-hot needles), group D (tapping plus cupping), and group E (Western medicine). The treatment was carried out twice a day in group E and once a day in the other four groups. The curative effect was observed on the 10th day of treatment; the cost was calculated for the five therapies, and the cost-effect ratio (C/E) and increment ratio (ΔC/ΔE) were analyzed.ResultsAfter the 10-day treatment, there was no statistical difference (P>0.05) in the curative effect among the five groups. Pain being alleviated one day faster than in group E amounted to a saving of RMB 21.90 yuan in group A, a saving of RMB 21.87 yuan in group B, a saving of RMB 26.00 yuan in group C, and a saving of RMB 20.23 yuan in group D. Compared with group C, the values of ΔC/ΔE were RMB 1.55, 2.81, and 0.21 yuan in groups A, B, and D, respectively.ConclusionsThe curative effect in groups A, B, C, and D was similar to that in group E, but the C/E was better than in group E
Variation Level Set Method for Multiphase Image Classification
Abstract-In this paper a multiphase image classification model based on variation level set method is presented. In recent years many classification algorithms based on level set method have been proposed for image classification. However, all of them have defects to some degree, such as parameters estimation and re-initialization of level set functions. To solve this problem, a new model including parameters estimation capability is proposed. Even for noise images the parameters needn't to be predefined. This model also includes a new term that forces the level set function to be close to a signed distance function. In addition, a boundary alignment term is also included in this model that is used for segmentation of thin structures. Finally the proposed model has been applied to both synthetic and real images with promising results
- …