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We study spin-wave excitations in multilayered magnetic nanograins composed of a stack of planes with perpendicular magnetic anisotropy. The inhomogeneity is modeled through the multiple repetition of a unit cell composed of layers of two different magnetic materials. The magnetic inhomogeneity along the central axis is found to split the frequency spectrum of magnetostatic excitations into two bands, while into the number of bands in the spectrum of exchange spin waves. We show that this difference in behavior is a result of the underlying long- and short-range interactions, respectively. We describe a way of increasing the role of the dipolar interactions in the formation of magnonic bands in patterned magnetic multilayers with perpendicular anisotropy, which can allow one to obtain ferromagnetic resonance spectra with two strong absorption peaks in low and high frequencies up to the sub-THz range. Our findings open a new area for modeling the spin-wave spectra of patterned magnetic multilayers with potential applications, and for studying the role of the microscopic magnetic structure in forming spin-wave spectra. [ABSTRACT FROM AUTHOR]

There is a growing interest in the field of acoustic metamaterials. These materials use periodic structures to exhibit properties not usually found in nature, such as negative mass or negative compressibility. The physics supporting these devices might seem counterintuitive at first, necessitating additional educational resources in this area. A leaky wave antenna (LWA) is a good example of a practical device that can be implemented as a standard material and a metamaterial. As the latter, the device extends its operational range, linking concepts related to both versions. This work presents an experimental open source kit designed for teaching the basic notions, including a computational routine for testing its analytical performance. The kit shown in this work has interchangeable units to experiment with several configurations (slit, axisymmetric, periodic hole, and membrane based metamaterial) and parameters of the antenna's design. The kit provides an opportunity to get hands-on experience on the real-life performance of LWAs, thanks to the use of low-cost materials, minimal equipment, and the practical nature of the antenna.

Sub-wavelength gratings (SWG) have shown much promise for applications such as lightweight high bandwidth reflectors, polarising filters and focusing lenses. Unfortunately, grating performance may be rapidly degraded through variability in grating dimensions. We demonstrate, in particular, how an error in depth of etch can be detrimental to the performance of zero contrast grating reflectors. We mitigate the impact of this fabrication error through the introduction of an etch stop layer and in so doing we experimentally realise a high bandwidth reflector based on this modified structure. Another common fabrication error is variation in the duty-cycle of fabricated gratings. This duty-cycle variation can weaken grating performance, however we demonstrate that grating designs that exhibit tolerance to duty-cycle fluctuation can be identified through simulation. Finally, we discuss the impact of lateral etching and the resulting sidewall concavity. We present our approach for numerically predicting the spectral response from such a grating and also for convenience we outline an approach for quickly approximating grating performance. Good agreement is observed between these numerical predictions and measurements made on a HCG with concave sidewalls.

Recurrences of Clostridium difficile infections lead to hospital readmissions and high costs, in addition to the suffering and frustration for the patients. Fidaxomicin has recently been introduced as a new antibiotic that has been shown to significantly reduce the recurrence of this infection. Despite this superiority, its high cost has led to very restrictive policies in its use, as such that many institutions only use it in patients with multiple recurrences. While waiting for new predictive clinical tools, we propose the development of scoring systems that allow the more high-risk patients to be treated earlier., (Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.)

We present a new material pairing that can be used to realize high-contrast gratings at wavelengths of 10 μm and greater. Using only optical lithography, the material pair solves the absorption issue limiting the popular Si/SiO 2 pairing from operation above 6 μm. We describe the obstacles that exist with the currently used grating materials for this wavelength range and outline why our chosen materials overcome this obstacle. We numerically demonstrate that gratings utilizing these materials are capable of wideband high reflectivity. We experimentally show that the spectral response of gratings that are fabricated using such a process show good agreement with theoretically predicted performance.

We propose an approach for the design of resonant cavities employed in magnetophotonic crystal (MPC) circulators and isolators. Starting from the analysis of a model circularly symmetric cavity, we show how to obtain a significant splitting of the eigenfrequencies of the two counterrotating cavity modes without introducing subdomains magnetized in opposite directions. Using the multiple-scattering method extended to handle uniaxial gyrotropic materials, we demonstrate numerically an MPC circulator working in a uniform external magnetic field.

Objective: The aim of the study was to ascertain the clinical and epidemiologic characteristics of patients with nosocomial or community-acquired Staphylococcus aureus bacteremic pneumonia., Methods: A prospective study of 134 cases diagnosed between January 1990 and December 1995 was performed., Results: Fifty cases involved primary bacteremic pneumonias, of which 80% were nosocomial (the majority, 72%, in intensive care unit patients, of whom 57% were post-surgery). Of the 84 cases of secondary pneumonia, 36 were non-intravenous drug users (78% nosocomial, of whom 43% were in the intensive care unit), and 48 cases were intravenous drug users (98% community-acquired)., Conclusions: Nosocomial S. aureus bacteremic pneumonia was especially frequent in intensive care unit patients (68.1%), and community-acquired pneumonia in intravenous drug users (72.3%). In non-intravenous drug users, clinical outcome and mortality were similar for nosocomial and community-acquired pneumonia.

Background: Respiratory infections are the most frequent reason for primary health care consultation. Although generally not severe, they are responsible for a large number of days of laboral and scholar absenteeism and an excessive use of antibiotics., Methods: The clinical and epidemiologic data of extrahospitalary infections in primary health care centers throughout Spain were collected according to the one day cut off system repeated trimestrally over one year., Results: Data of 3,732 days of consultation were collected in which a total of 144,608 patients were attended. Of these, 20,614 had respiratory infections and 11,684 extrarespiratory infections. The most frequent processes were pharyngitis (33.7%), common cold (31.7%) followed by bronchitis (18.7%), otitis (11%), influenza (4.6%), laryngitis (4%), sinusitis (3.6%) and pneumonia (1.8%). Antibiotic treatment was prescribed in 13,488 patients (65%). The type of antibiotic was analyzed in the 11,977 patients treated for only one infection. Penicillins were the antibiotics most used followed by cephalosporins. The antibiotic prescribed was considered adequate in 70% of the 8,484 patients treated for potentially bacterial infection. A total of 3,493 patients had infection considered to be of viral etiology., Conclusions: Twenty-two percent of the patients attending a primary health care center presented infection and of these two out of three cases had respiratory infection. Pharyngitis and common cold were the most frequent processes observed. Two thirds of the patients consulting for respiratory infection received antibiotic treatment, with 29.2% being diagnosed with infections considered to be of viral etiology. The empiric treatment chosen for the two thirds of the potentially bacterial infections was considered as adequate.

Objective: To determine the prevalence and causes of meningitis in patients with human immunodeficiency virus (HIV) infection., Design: A prospective study of HIV-associated neurologic complications carried out from 1988 to 1992., Setting: A tertiary care university hospital in Madrid, Spain. PATIENTS. A total of 142 patients, 65% of whom were injecting drug users., Results: Thirty-six episodes of meningitis were diagnosed in 33 patients (23%). Of these, 17 cases (47%) were tuberculous meningitis (5 definite and 12 probable) and 7 (19%) corresponded to cryptococcal meningitis. Comparative studies of the tuberculous and cryptococcal meningitis cases showed injecting drug use as the most common form of HIV transmission in the tuberculous meningitis (P = .03) and a lower mean CD4+ cell count in the cryptococcal meningitis group (P = .02)., Conclusions: Tuberculous meningitis was the prime type of meningitis, which was associated with HIV transmission by injecting drug use. Cryptococcal meningitis appears in more advanced stages of HIV infection, which determines its characteristic presentation.

Background: Production of beta-lactamase by normal pharyngeal flora could account for penicillin treatment failure in patients with acute streptococcal pharyngitis. The aim of the present investigation was to study the beta-lactamase-producing bacteria (BLPB) in 58 patients with acute pharyngitis, and to investigate the impact of two antibiotics, amoxycillin vs amoxycillin/clavulanic acid in the pharyngeal microflora., Methods: Rapid antigen detection tests for S. pyogenes and standard microbiologic cultures were performed on simultaneously obtained throat swabs from each enrolled patient. Patients with group A streptococcal pharyngitis (GASP) were randomized in two groups: patients treated with 10 days of oral amoxycillin (group I), and patients treated with 10 days of oral amoxicyllin/clavulanic acid (group II). Patients without GASP and without antibiotic treatment were considered as controls (group III). Cultures were repeated 15 days following the first culture. All of them were processed for aerobic and anaerobic organisms., Results: S. pyogenes was recovered in 25 patients (43.1%) and BLPB were isolated in 64% of the treated patients and in 78% of the non-treated control patients. We observed that the number of patients harboring BLPB did not change significantly in the untreated control group. After treatment we detected a similar increase in the number of patients harboring BLPB in groups I and II. In the present study BLPB were found in more than 70% of the patients and the failure rate was less than 10%., Conclusions: The results of this study indicate that production of beta-lactamase by pharyngeal organisms does not fully explain the failures of penicillin therapy for acute streptococcal pharyngitis.