3,367 research outputs found
Gapless Hamiltonians for the toric code using the PEPS formalism
We study Hamiltonians which have Kitaev's toric code as a ground state, and
show how to construct a Hamiltonian which shares the ground space of the toric
code, but which has gapless excitations with a continuous spectrum in the
thermodynamic limit. Our construction is based on the framework of Projected
Entangled Pair States (PEPS), and can be applied to a large class of
two-dimensional systems to obtain gapless "uncle Hamiltonians".Comment: 8 pages, 2 figure
Recovering and harmonizing research cruises information
The IEO has maintained since late 60s, a local database with basic information on oceanographic campaigns, formerly known as ROSCOF reports, which were established in the framework of IODE initiatives, as a low-level inventory for future access to data. Technological advances in recent decades and different coordination activities between NODCs have favored the implementation of these reports in standardized digital formats (Cruise Summary Reports, CSR) that allow their integration in international repositories as SeaDataNet or POGO.
However, this inventory and cataloging activity has suffered ups and downs over 40 years of activity, changes in storage criteria and periods of less activity. In the search for a unique criterion that can last over time and that unifies this information as much as possible with the data generated in these campaigns, an exhaustive review of the existing information has been carried out
Electromyography: a simple and accessible tool to assess physical performance and health during hypoxia training. A systematic review
Hypoxia causes reduced partial pressure of oxygen in arterial blood and induces
adaptations in skeletal muscle that may affect individuals’ physical performance and muscular
health. These muscular changes are detectable and quantifiable by electromyography (EMG),
an instrument that assesses electrical activity during active contraction at rest. EMG is a relatively
simple and accessible technique for all patients, one that can show the degree of the sensory and
motor functions because it provides information about the status of the peripheral nerves and muscles.
The main goal of this review is to evaluate the scientific evidence of EMG as an instrument for
monitoring different responses of skeletal muscles subjected to external stimuli such as hypoxia and
physical activity. A structured search was conducted following the Preferred Reporting Items for
Systematic Review and Meta-Analyses (PRISMA) guidelines in Medline/PubMed, Scielo, Google
Scholar, Web of Science, and Cochrane Library Plus. The search included articles published in the last
25 years until May 2020 and was restricted to English- and Spanish-language publications. As such,
investigators identified nine articles that met the search criteria. The results determined that EMG
was able to detect muscle fatigue from changes in the frequency spectrum. When a muscle was
fatigued, high frequency components decreased and low frequency components increased. In other
studies, EMG determined muscle activation increased during exercise by recruiting motor units and
by increasing the intensity of muscle contractions. Finally, it was also possible to calculate the mean
quadriceps quadratic activity used to obtain an image of muscle activation. In conclusion, EMG offers
a suitable tool for monitoring the different skeletal muscle responses and has sufficient sensitivity to
detect hypoxia-induced muscle changes produced by hypoxic stimuli. Moreover, EMG enhances an
extension of physical examination and tests motor-system integrity
Recovering and harmonizing research cruises information
The IEO has maintained since late 60s, a local database with basic information on oceanographic campaigns, formerly known as ROSCOF reports, which were established in the framework of IODE initiatives, as a low-level inventory for future access to data. Technological advances in recent decades and different coordination activities between NODCs have favored the implementation of these reports in standardized digital formats (Cruise Summary Reports, CSR) that allow their integration in international repositories as SeaDataNet or POGO.
However, this inventory and cataloging activity has suffered ups and downs over 40 years of activity, changes in storage criteria and periods of less activity. In the search for a unique criterion that can last over time and that unifies this information as much as possible with the data generated in these campaigns, an exhaustive review of the existing information has been carried out.
The result has been the retrieval of information from short-term campaigns carried out on smaller vessels with great coastal activity, as well as updating information regarding old campaigns performed on the first half of the 20th century onboard of decommissioned
vessels. All this is completed with the systematic campaigns carried out by INTECMAR in the Galician rias, research vessels operated by the national Fisheries Administration, and information on research surveys carried out by foreign ships in national waters, forming a catalog of more than 4000 entries.
This approach is also followed by the UTM-CSIC, on its own-managed vessels and campaigns carried out since 1991. The common approach allows a unified response to the governmental needs for the planning of future campaigns, and in successive improvements in data recovering, archiving and accessing at NODC/CEDO
Strain-balanced type-II superlattices for efficient multi-junction solar cells
Multi-junction solar cells made by assembling semiconductor materials with different bandgap energies have hold the record conversion efficiencies for many years and are currently approaching 50%. Theoretical efficiency limits make use of optimum designs with the right lattice constant-bandgap energy combination, which requires a 1.0–1.15 eV material lattice-matched to GaAs/Ge. Nevertheless, the lack of suitable semiconductor materials is hindering the achievement of the predicted efficiencies, since the only candidates were up to now complex quaternary and quinary alloys with inherent epitaxial growth problems that degrade carrier dynamics. Here we show how the use of strain-balanced GaAsSb/GaAsN superlattices might solve this problem. We demonstrate that the spatial separation of Sb and N atoms avoids the ubiquitous growth problems and improves crystal quality. Moreover, these new structures allow for additional control of the effective bandgap through the period thickness and provide a type-II band alignment with long carrier lifetimes. All this leads to a strong enhancement of the external quantum efficiency under photovoltaic conditions with respect to bulk layers of equivalent thickness. Our results show that GaAsSb/GaAsN superlattices with short periods are the ideal (pseudo)material to be integrated in new GaAs/Ge-based multi-junction solar cells that could approach the theoretical efficiency limit
Ear, nose and throat manifestations in pemphigus vulgaris
Pemphigus vulgaris (PV) is an autoimmune disease characterized by mucocutaneous intraepithelial blisters and pathogenic autoantibodies against desmoglein 3. There are two clinical forms: mucosal (MPV) and mucocutaneous (MCPV). The frequency of ear, nose and throat (ENT) involvement in PV is not clearly defined. Only a few isolated individual cases have been reported.
OBJECTIVES: The objective of our study was to determine the incidence of ENT involvement in patients with PV.
PATIENTS: We studied prospectively all 16 patients diagnosed with PV and treated in the Department of Dermatology of the University Clinic of Navarra between 2001 and 2005. They were 10 cases of MPV and six cases of MCPV. All patients were evaluated for ENT manifestations by endoscopic examination.
RESULTS: Of the 16 patients, 13 presented with throat symptoms (81%), 12 pharyngeal (75%) and seven laryngeal symptoms (44%). Fourteen patients (88%) had active PV lesions on endoscopic evaluation (eight patients had active lesions on both pharyngeal and laryngeal mucosa, four had PV lesions only on laryngeal mucosa and two had PV lesions on pharyngeal mucosa). Laryngeal lesions were most commonly present in MPV patients. The frequency of nasal symptoms (38%) was lower than active PV lesions (62%) found on ENT examination. Oral symptoms and oral active PV lesions were the most frequent findings (94%). Only three patients with MCPV showed erosions on the external auditory canal.
CONCLUSIONS: As ENT endoscopy allows more extensive areas of mucosa to be examined than simple visual inspection, we recommend that it be included in the examination of all patients with PV. By obtaining more complete information concerning the extent of the disease, a more accurate diagnosis can be made, better choice of drug and dose may be decided and, ultimately, response to treatment may be improved
SAFARI optical system architecture and design concept
SpicA FAR infrared Instrument, SAFARI, is one of the instruments planned for the SPICA mission. The SPICA mission is the next great leap forward in space-based far-infrared astronomy and will study the evolution of galaxies, stars and planetary systems. SPICA will utilize a deeply cooled 2.5m-class telescope, provided by European industry, to realize zodiacal background limited performance, and high spatial resolution. The instrument SAFARI is a cryogenic grating-based point source spectrometer working in the wavelength domain 34 to 230 ÎĽm, providing spectral resolving power from 300 to at least 2000. The instrument shall provide low and high resolution spectroscopy in four spectral bands. Low Resolution mode is the native instrument mode, while the high Resolution mode is achieved by means of a Martin-Pupplet interferometer. The optical system is all-reflective and consists of three main modules; an input optics module, followed by the Band and Mode Distributing Optics and the grating Modules. The instrument utilizes Nyquist sampled filled linear arrays of very sensitive TES detectors. The work presented in this paper describes the optical design architecture and design concept compatible with the current instrument performance and volume design drivers
Voz del anciano
La vejez es en sĂ un fenĂłmeno biolĂłgico que no implica necesariamente
una enfermedad. Los fenĂłmenos biolĂłgicos del envejecimiento se inician
en edades muy tempranas y tiene la capacidad de modificarse,
preveerse y compensarse.
La educaciĂłn y la preparaciĂłn para posibles deterioros debe de ser contemplada
desde un plano preventivo. En el ser humano la apariciĂłn del
lenguaje y su vehĂculo habitual, la voz; representĂł la posibilidad de
aumentar su longevidad.
El deterioro vocal del anciano se conoce como presbifonĂa y en ocasiones
interfiere significativamente en la capacidad de comunicaciĂłn y en
la calidad de vida de las personas ancianas. Al considerar la presbifonĂa
o voz senil hay que distinguir dos situaciones clĂnicas distintas desde el
punto de vista conceptual: la disfonĂa del anciano y la disfonĂa en el
anciano.
Se comentan los aspectos del envejecimiento en relaciĂłn con la voz, la
valoraciĂłn y la caracterizaciĂłn de la voz en el anciano y las estrategias
para prevenir el deterioro y tratar los trastornos especĂficos de la voz en
las personas mayores, bien sea desde el punto de vista funcional o
rehabilitaciĂłn o bien mediante cirugĂa
Adherence to treatment and related factors among patients with chronic conditions in primary care: a cross-sectional study
Background: Adherence to treatment, a public health issue, is of particular importance in chronic disease therapies. Primary care practices offer ideal venues for the effective care and management of these conditions. The aim of this study is to assess adherence to treatment and related-factors among patients with chronic conditions in primary care settings.
Methods: A cross-sectional study was conducted among 299 adult patients with ≥1 chronic condition(s) and prescribed medication in primary healthcare centers of Spain. The Morisky-Green-Levine questionnaire was used to assess medication adherence via face-to-face interviews. Crude and adjusted multivariable logistic regression models were used to analyze factors associated with adherence using the Multidimensional Model proposed by the World Health Organization — social and economic, healthcare team and system-related, condition-related, therapy-related, and patient-related factors.
Results: The proportion of adherent patients to treatment was 55.5%. Older age (adjusted odds ratio 1.31 per 10- year increment, 95% CI 1.01–1.70), lower number of pharmacies used for medication refills (0.65, 95% CI 0.47– 0.90), having received complete treatment information (3.89, 95% CI 2.09–7.21), having adequate knowledge about medication regimen (4.17, 95% CI 2.23–7.80), and self-perception of a good quality of life (2.17, 95% CI 1.18–4.02) were independent factors associated with adherence.
Conclusions: Adherence to treatment for chronic conditions remained low in primary care. Optimal achievement of appropriate levels of adherence through tailored multifaceted interventions will require attention to the multidimensional factors found in this study, particularly those related to patients’ education and their information needs
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