New Non-deterministic Approaches for Register Allocation

In this paper two algorithms for register allocation are presented. The first algorithm is a simulated annealing algorithm. The core of the algorithm is the Metropolis procedure. The algorithm presented in the paper has a linear time asymptotic complexity. The second algorithm is a genetic algorithm. The algorithm has a linear time complexity

Ramanovi i fotoluminescentni spektri čistih i kositrom obogaćenih tankih slojeva CdS pripremljenih prskanjem i pirolizom

Thin films of CdS, pure and enriched with different concentrations of tin up to 6%, were prepared by the spray pyrolysis technique. All samples were prepared at the deposition temperature of 420 ◦C. The XRD diagnostic data of the investigated samples revealed the polycrystalline nature of the as-deposited samples. The main characteristic peaks of CdS appeared in both pure and enriched films prepared by all used methods. The enrichment of Sn has no effect on positions of the characteristic peaks. The observed effect of Sn enrichment is the change in peak broadening which increases with the increase of Sn concentration. The thickness values ranged from 0.65 up to 1.15 µm. The samples of pure CdS show a sharp absorption edge at about 2.43 eV. The absorption coefficient α of the investigated samples was calculated from transmission and reflection spectra. Photoluminescence measurements show red emission band of the as-deposited samples, which was quenched by Sn incorporation. This band is ascribed to the excess of Cd which was checked by the energy dispersive X-ray (EDX) spectrometry. Raman spectra of samples with different concentrations of Sn were studied. They show remarkable increase of intensity when increasing the film thickness and decreasing the Sn concentration.Metodom prskanja i pirolize pripremali smo čiste i do 6% kositrom obogaćene tanke slojeve CdS. Sve uzorke smo pripremali na temperaturi polaganja od 420 ◦C. XRD spektri ispitivanih uzoraka pokazuju polikristaliničnu strukturu. Glavni karakteristični vrhovi CdS vide se i u čistim i u obogaćenim uzorcima pripremljenim primijenjenim metodama. Obogaćenje kositrom nema utjecaja na položaje karakterističnih vrhova. Međutim, javlja se proširenje vrhova koje se povećava pri povećanim koncentracijama kositra. Izmjerene i izračunate debljine slojeva su u skladu. Debljine slojeva bile su između 0.65 i 1.15 µm. Uzorci CdS pokazuju oštar apsorpcijski rub na oko 2.43 eV. Apsorpcijske koeficijente α ispitivanih uzoraka smo izveli iz transmisijskih i refleksijskih spektara. Mjerenja fotoluminescencije pokazuju crvenu emisijsku vrpcu koja trne dodavanjem kositra. Ta se vrpca tumači viškom Cd što smo potvrdili disperzivnom rendgenskom spektrometrijom (EDX). Proučavali smo i Ramanove spektre uzoraka s raznim koncentracijama kositra. Oni pokazuju snažan porast intenziteta za slojeve veće debljine i manje koncentracije kositra

Scattering of surface electrons by isolated steps versus periodic step arrays

We investigate the scattering of electrons belonging to Shockley states of (111)-oriented noble metal surfaces using angle-resolved photoemission (ARPES) and scanning tunneling microscopy (STM). Both ARPES and STM indicate that monatomic steps on a noble metal surface may act either as strongly repulsive or highly transmissive barriers for surface electrons, depending on the coherence of the step lattice, and irrespectively of the average step spacing. By measuring curved crystal surfaces with terrace length ranging from 30 to 180 Å, we show that vicinal surfaces of Au and Ag with periodic step arrays exhibit a remarkable wave function coherence beyond 100 Å step spacings, well beyond the Fermi wavelength limit and independently of the projection of the bulk band gap on the vicinal plane. In contrast, the analysis of transmission resonances investigated by STM shows that a pair of isolated parallel steps defining a 58 Å wide terrace confines and decouples the surface state of the small terrace from that of the (111) surface. We conclude that the formation of laterally confined quantum well states in vicinal surfaces as opposed to propagating superlattice states depends on the loss of coherence driven by imperfection in the superlattice order. © 2013 American Physical Society.This work was supported in part by the Spanish MICINN (MAT2007-63083 and MAT2010-15659), the Basque Government (IT-257-07), and the Agència de Gestió d’Ajuts Universitaris i de Recerca (2009 SGR 695). The SRC is funded by the National Science Foundation (Award No. DMR-0084402). A.M. and J.L.-C. acknowledge funding from the Ramon y Cajal Fellowship program.Peer Reviewe

Atomically-precise texturing of hexagonal boron nitride nanostripes

Monolayer hexagonal boron nitride (hBN) is attracting considerable attention because of its potential applications in areas such as nano- and opto-electronics, quantum optics and nanomagnetism. However, the implementation of such functional hBN demands precise lateral nanostructuration and integration with other two-dimensional materials, and hence, novel routes of synthesis beyond exfoliation. Here, a disruptive approach is demonstrated, namely, imprinting the lateral pattern of an atomically stepped one-dimensional template into a hBN monolayer. Specifically, hBN is epitaxially grown on vicinal Rhodium (Rh) surfaces using a Rh curved crystal for a systematic exploration, which produces a periodically textured, nanostriped hBN carpet that coats Rh(111)-oriented terraces and lattice-matched Rh(337) facets with tunable width. The electronic structure reveals a nanoscale periodic modulation of the hBN atomic potential that leads to an effective lateral semiconductor multi-stripe. The potential of such atomically thin hBN heterostructure for future applications is discussed.The authors acknowledge financial support from the Spanish Ministry of Science and Innovation (Grants MAT-2017-88374-P, PID2019-107338RB-C63, MAT2017-88492-R, and Severo Ochoa CEX2019-000910-S), the CSIC (Grant 2020AEP178), the Basque Government (Grant IT-1255-19), the Marie Sklodowska-Curie European Union's Horizon 2020 program (grant MagicFACE 797109), the European Research Council (Advanced Grant 789104-eNANO), and Elettra Sincrotrone Trieste for providing access to its synchrotron radiation facilities. I.P. and F.B. acknowledge funding from EUROFEL, and D.U. from the Ministry of Science and Higher Education of the Russian Federation [Grant No. 075-15-2020-797 (13.1902.21.0024)]. A.A.M. acknowledges the German Ministry for Education and Research (Grant 05K19KER).Peer reviewe

Concurrent validity of self-rating scale of self-directed learning and self-directed learning instrument among Italian nursing students

BACKGROUND: Self-Directed Learning develops when students take the initiative for their learning, recognising needs, formulating goals, identifying resources, implementing appropriate strategies and evaluating learning outcomes. This should be seen as a collaborative process between the nurse educator and the learner. At the international level, various instruments have been used to measure Self-Directed Learning abilities (SDL), both in original and in culturally-adapted versions. However, few instruments have been subjected to full validation, and no gold standard reference has been established to date. In addition, few researchers have adopted the established tools to assess the concurrent validity of the emerging new tools. Therefore, the aim of this study was to measure the concurrent validity between the Self-Rating Scale of Self-Directed Learning (SRSSDL_Ita) - Italian version and the Self-Directed Learning Instruments (SDLI) in undergraduate nursing students. METHODS: A concurrent validity study design was conducted in a Bachelor level nursing degree programme located in Italy. All nursing students attending the first, second or third year (n=428) were the target sample. The SRSSDL_Ita, and the SDLI were used. The Pearson correlation was used to determine the concurrent validity between the instruments; the confidence of intervals (CI 95%) bias-corrected and accelerated bootstrap (BCa), were also calculated. RESULTS: The majority of participants were students attending their first year (47.9%), and were predominately female (78.5%). Their average age was 22.5\ub14.1. The SDL abilities scores, as measured with the SRSSDL_Ita (min 40, max 200), were, on average, 160.79 (95% CI 159.10-162.57; median 160); while with the SDLI (min 20, max 100), they were on average 82.57 (95% CI 81.79-83.38; median 83). The Pearson correlation between the SRSSDL_Ita and SDLI instruments was 0.815 (CI BCa 95% 0.774-0.848), (p=0.000). CONCLUSIONS: The findings confirm the concurrent validity of the SRSSDL_Ita with the SDLI. The SRSSDL_Ita instrument can be useful in the process of identifying Self-Directed Learning abilities, which are essential for students to achieve the expected learning goals and become lifelong learners

Plant growth-promoting actinobacteria: a new strategy for enhancing sustainable production and protection of grain legumes

Grain legumes are a cost-effective alternative for the animal protein in improving the diets of the poor in South-East Asia and Africa. Legumes, through symbiotic nitrogen fixation, meet a major part of their own N demand and partially benefit the following crops of the system by enriching soil. In realization of this sustainability advantage and to promote pulse production, United Nations had declared 2016 as the “International Year of pulses”. Grain legumes are frequently subjected to both abiotic and biotic stresses resulting in severe yield losses. Global yields of legumes have been stagnant for the past five decades in spite of adopting various conventional and molecular breeding approaches. Furthermore, the increasing costs and negative effects of pesticides and fertilizers for crop production necessitate the use of biological options of crop production and protection. The use of plant growth-promoting (PGP) bacteria for improving soil and plant health has become one of the attractive strategies for developing sustainable agricultural systems due to their eco-friendliness, low production cost and minimizing consumption of non-renewable resources. This review emphasizes on how the PGP actinobacteria and their metabolites can be used effectively in enhancing the yield and controlling the pests and pathogens of grain legumes

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18–49, 50–69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population

Laparoscopy in management of appendicitis in high-, middle-, and low-income countries: a multicenter, prospective, cohort study.

BACKGROUND: Appendicitis is the most common abdominal surgical emergency worldwide. Differences between high- and low-income settings in the availability of laparoscopic appendectomy, alternative management choices, and outcomes are poorly described. The aim was to identify variation in surgical management and outcomes of appendicitis within low-, middle-, and high-Human Development Index (HDI) countries worldwide. METHODS: This is a multicenter, international prospective cohort study. Consecutive sampling of patients undergoing emergency appendectomy over 6 months was conducted. Follow-up lasted 30 days. RESULTS: 4546 patients from 52 countries underwent appendectomy (2499 high-, 1540 middle-, and 507 low-HDI groups). Surgical site infection (SSI) rates were higher in low-HDI (OR 2.57, 95% CI 1.33-4.99, p = 0.005) but not middle-HDI countries (OR 1.38, 95% CI 0.76-2.52, p = 0.291), compared with high-HDI countries after adjustment. A laparoscopic approach was common in high-HDI countries (1693/2499, 67.7%), but infrequent in low-HDI (41/507, 8.1%) and middle-HDI (132/1540, 8.6%) groups. After accounting for case-mix, laparoscopy was still associated with fewer overall complications (OR 0.55, 95% CI 0.42-0.71, p < 0.001) and SSIs (OR 0.22, 95% CI 0.14-0.33, p < 0.001). In propensity-score matched groups within low-/middle-HDI countries, laparoscopy was still associated with fewer overall complications (OR 0.23 95% CI 0.11-0.44) and SSI (OR 0.21 95% CI 0.09-0.45). CONCLUSION: A laparoscopic approach is associated with better outcomes and availability appears to differ by country HDI. Despite the profound clinical, operational, and financial barriers to its widespread introduction, laparoscopy could significantly improve outcomes for patients in low-resource environments. TRIAL REGISTRATION: NCT02179112