Vortex phases in superconducting Nb thin films with periodic pinning

Magnetotransport properties have been used to investigate vortex phases in Nb films with periodic arrays of magnetic pinning centers. This kind of samples show a continuous glass transition similar to that observed in Nb plain films, but the periodic pinning yields different critical exponents and enhanced glass transition temperature at the matching field

Super congruences and Euler numbers

Let $p>3$ be a prime. We prove that $$\sum_{k=0}^{p-1}\binom{2k}{k}/2^k=(-1)^{(p-1)/2}-p^2E_{p-3} (mod p^3),$$ $$\sum_{k=1}^{(p-1)/2}\binom{2k}{k}/k=(-1)^{(p+1)/2}8/3*pE_{p-3} (mod p^2),$$ $$\sum_{k=0}^{(p-1)/2}\binom{2k}{k}^2/16^k=(-1)^{(p-1)/2}+p^2E_{p-3} (mod p^3)$$, where E_0,E_1,E_2,... are Euler numbers. Our new approach is of combinatorial nature. We also formulate many conjectures concerning super congruences and relate most of them to Euler numbers or Bernoulli numbers. Motivated by our investigation of super congruences, we also raise a conjecture on 7 new series for $\pi^2$, $\pi^{-2}$ and the constant $K:=\sum_{k>0}(k/3)/k^2$ (with (-) the Jacobi symbol), two of which are $$\sum_{k=1}^\infty(10k-3)8^k/(k^3\binom{2k}{k}^2\binom{3k}{k})=\pi^2/2$$ and $$\sum_{k>0}(15k-4)(-27)^{k-1}/(k^3\binom{2k}{k}^2\binom{3k}k)=K.$

Cambio climático en DAPA

Presentación del dr. Andrew Jarvis, director de Decision and Policy Analysis del CIAT, durante la primera Casa Abierta de 2013, dirigida a decanos y docentes

The cumulative effect of core lifestyle behaviours on the prevalence of hypertension and dyslipidemia

Background: Most cardiovascular disease (CVD) occurs in the presence of traditional risk factors, including hypertension and dyslipidemia, and these in turn are influenced by behavioural factors such as diet and lifestyle. Previous research has identified a group at low risk of CVD based on a cluster of inter-related factors: body mass index (BMI) < 25 Kg/m2, moderate exercise, alcohol intake, non-smoking and a favourable dietary pattern. The objective of this study was to determine whether these factors are associated with a reduced prevalence of hypertension and dyslipidemia in an Irish adult population. Methods: The study was a cross-sectional survey of 1018 men and women sampled from 17 general practices. Participants completed health, lifestyle and food frequency questionnaires and provided fasting blood samples for analysis of glucose and insulin. We defined a low risk group based on the following protective factors: BMI <25 kg/m2; waist-hip ratio (WHR) <0.85 for women and <0.90 for men; never smoking status; participants with medium to high levels of physical activity; light alcohol consumption (3.5–7 units of alcohol/week) and a "prudent" diet. Dietary patterns were assessed by cluster analysis. Results: We found strong significant inverse associations between the number of protective factors and systolic blood pressure, diastolic blood pressure and dyslipidemia. The prevalence odds ratio of hypertension in persons with 1, 2, 3, ≥ 4 protective factors relative to those with none, were 1.0, 0.76, 0.68 and 0.34 (trend p < 0.01). The prevalence odds ratio of dyslipidemia in persons with 1, 2, 3, ≥ 4 protective factors relative to those with none were 0.83, 0.98, 0.49 and 0.24 (trend p = 0.001). Conclusion: Our findings of a strong inverse association between low risk behaviours and two of the traditional risk factors for CVD highlight the importance of 'the causes of the causes' and the potential for behaviour modification in CVD prevention at a population level

Proof of concept of a novel neck-situated wearable PPG system for continuous physiological monitoring

Continuous overnight vital signs monitoring would be ideal for patients suffering from epilepsy, where life-threatening hypoxemias can occur during sleep. However, the existing physiological monitoring systems suffer from limitations in terms of usability factors and/or limited information of the signals being acquired. The body location of the monitoring system is a crucial consideration, seldom addressed by the wider community. This article presents a proof-of-concept, neck-worn photoplethysmography system, which was developed and tested to assess the feasibility of the neck as a monitoring site for longitudinal sensing of cardiac and respiratory responses during sleep. The novel system was compared against a gold-standard commercial multichannel cardiorespiratory polysomnography (PSG) system during oxygen desaturation cycles, to assess its ability to measure heart rate, respiratory rate (RR), and peripheral blood oxygen saturation (SpO 2 ) on 15 participants. The findings for heart rate showed a marginal mean error of 0.47 beats/min with limits of agreement (LOA) at 95% confidence between −3.17 and 4 bpm. RR comparisons had an overall mean error of 0.43 breaths/min, with LOA at 95% confidence between −2.73 and 3.3 bpm. Lastly, the system accurately outputs SpO 2 with an overall root-mean-square error of 1.44% between 90 and 100% SpO 2 using a custom calibration method. Moreover, it was observed that the neck made it possible for the system to detect desaturation events on an average 12.6 s prior to the PSG system, which used a peripheral finger-based PPG system. Ultimately, this proof-of-concept study illustrates the viability of neck-based sensing for minimally invasive monitoring of cardiac and respiratory vitals during sleep

Ferromagnetic/superconducting proximity effect in La0.7Ca0.3MnO3 / YBa2Cu3O7 superlattices

We study the interplay between magnetism and superconductivity in high quality YBa2Cu3O7 (YBCO) / La0.7Ca0.3MnO3(LCMO)superlattices. We find evidence for the YBCO superconductivity depression in presence of the LCMO layers. We show that due to its short coherence length superconductivity survives in the YBCO down to much smaller thickness in presence of the magnetic layer than in low Tc superconductors. We also find that for a fixed thickness of the superconducting layer, superconductivity is depressed over a thickness interval of the magnetic layer in the 100 nm range. This is a much longer length scale than that predicted by the theory of ferromagnetic/superconducting proximity effect.Comment: 10 pages + 5 figures, submitted to Phys. Rev.

The genome of Bacillus tequilensis EA-CB0015 sheds light into its epiphytic lifestyle and potential as a biocontrol agent

Different Bacillus species have successfully been used as biopesticides against a broad range of plant pathogens. Among these, Bacillus tequilensis EA-CB0015 has shown to efficiently control Black sigatoka disease in banana plants, presumably by mechanisms of adaptation that involve modifying the phyllosphere environment. Here, we report the complete genome of strain EA-CB0015, its precise taxonomic identity, and determined key genetic features that may contribute to its effective biocontrol of plant pathogens. We found that B. tequilensis EA-CB0015 harbors a singular 4 Mb circular chromosome, with 3,951 protein-coding sequences. Multi-locus sequence analysis (MLSA) and average nucleotide identity (ANI) analysis classified strain EA-CB0015 as B. tequilensis. Encoded within its genome are biosynthetic gene clusters (BGCs) for surfactin, iturin, plipastatin, bacillibactin, bacilysin, subtilosin A, sporulation killing factor, and other natural products that may facilitate inter-microbial warfare. Genes for indole-acetic acid (IAA) synthesis, the use of diverse carbon sources, and a multicellular lifestyle involving motility, biofilm formation, quorum sensing, competence, and sporulation suggest EA-CB0015 is adept at colonizing plant surfaces. Defensive mechanisms to survive invading viral infections and preserve genome integrity include putative type I and type II restriction modification (RM) and toxin/antitoxin (TA) systems. The presence of bacteriophage sequences, genomic islands, transposable elements, virulence factors, and antibiotic resistance genes indicate prior occurrences of genetic exchange. Altogether, the genome of EA-CB0015 supports its function as a biocontrol agent against phytopathogens and suggest it has adapted to thrive within phyllosphere environments

Europium luminescence from amorphous yttrium alumina films on fused silica substrates

In this work, we investigate photoluminescence of sol-gel derived films corresponding to yttrium alumina garnet Y3Al5O12 doped with trivalent europium. The films with three concentrations of europium 0,02; 0,025; 0,03 M with the thickness 210-220 nm were deposited on fused silica substrates by the corresponding sols’ spinning followed by drying and high temperature annealing at 1000 °С for 30 min. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive Х-ray (EDX) analysis as well as ellipsometry, photoluminescence (PL) and photoluminescence excitation spectroscopy (PLE). All of the fabricated samples were amorphous and revealed room-temperature luminescence bands within the range of 550 – 750 nm corresponding to 5D0 → 7Fj (j=0,..,4) transitions of trivalent europium ions with the most intensive bands at 610 – 630 nm and 680 – 710 nm. The intensity of europium luminescence increases with europium concentration. The photoluminescence excitation spectra measured at the emission wavelength 710 nm exhibit strong bands at 220 nm, which could be associated with absorption of exciting light within Eu3+ - O2-bands. Practical application of the obtained films transforming ultraviolet irradiation into visible is discussed