500 research outputs found
Ten Years of Airbnb Phenomenon Research: A Bibliometric Approach (2010–2019)
The interest in the Airbnb phenomenon is represented in the fast growth of publications indexed in the Web of Science (WoS) since the research inception of this topic in 2010. However, there are no studies that analyze the incidence of this phenomenon from a bibliometric approach using WoS. Therefore, this paper aims to quantify the incidence and composition of the Airbnb phenomenon through bibliometrics taken it as a data source. To achieve this aim, the WoS statistical instruments and the bibliometric tool VOSviewer are used. The results obtained, such as the number of articles and citations per year, the main categories of these articles, the nationalities of the authors, the most productive institutions, the sources and authors in terms of publications, and the H-Core of the most cited articles, are presented. Finally, concept maps are exposed, representing the relatedness of co-authorship and co-citation among authors, as well as the co-occurrence of the keywords in the articles analyzed. Satisfaction, trust, and innovation appear as the main research lines. This paper can be useful for academics and professionals, giving them a holistic overview of the topic, identifying new research areas, or as an objective manner to literary review approaches
Antibacterial activity in three Chaetoceros microalgae species cultures by using antibiotics
Diatoms, such as Chaetoceros, grow in a mutualistic relationship with bacteria. However, in some cases, it is necessary to grow them in bacteria-free cultures. To reduce bacterial load, antibiotics are used, and on certain occasions it is necessary to use a mixture with more than one antibiotic. This work aimed to obtain a quick and effective protocol to reduce the bacterial load and evaluate the response of three Chaetoceros species with aquacultural importance. Single and mix antibiotics were used. Microalgal and bacterial growth was measured. The growth parameters for diatoms showed that the significantly highest cell concentration was for C. muelleri (3.15 x106 cells mL-1) and the lowest values to C. calcitrans (2.98 x106 cells mL-1). The significantly highest growth rate was for C. calcitrans (0.77 divisions per day), and the lowest values for Chaetoceros sp. (0.60 divisions per day). The growth parameters for heterotrophic bacteria showed that the significantly highest bacterial load was for Chaetoceros sp. (19.16 x106 CFU (Colony-Forming Units) mL-1) and the lowest values were for C. calcitrans (12.23 x106 CFU mL-1). The growth rate of the heterotrophic bacteria present in Chaetoceros cultures was similar among the three studied species. Streptomycin® and sulfate G41® produced a partial reduction of bacterial load. The most effective treatment for all three species was the use of an antibiotic mix composed of ampicillin® (250 μg mL-1), kanamycin® (200 μg mL-1), neomycin® (50 μg mL-1), and streptomycin® (100 μg mL-1) for three days. The mix prepared with the highest antibiotic concentration produced a reduction of bacteria (100%) for three days; however, it also induced a significant reduction of the growth of the three Chaetoceros species
Deconvolution problems in x-ray absorption fine structure
A Bayesian method application to the deconvolution of EXAFS spectra is
considered. It is shown that for purposes of EXAFS spectroscopy, from the
infinitely large number of Bayesian solutions it is possible to determine an
optimal range of solutions, any one from which is appropriate. Since this
removes the requirement for the uniqueness of solution, it becomes possible to
exclude the instrumental broadening and the lifetime broadening from EXAFS
spectra. In addition, we propose several approaches to the determination of
optimal Bayesian regularization parameter. The Bayesian deconvolution is
compared with the deconvolution which uses the Fourier transform and optimal
Wiener filtering. It is shown that XPS spectra could be in principle used for
extraction of a one-electron absorptance. The amplitude correction factors
obtained after deconvolution are considered and discussed.Comment: 6 two-column pages, 5 eps figures; submitted to J. Phys.: Appl. Phy
Geochemical study of products associated with spontaneous oxidation of coal in the Cerro Pelado Formation, Venezuela
The aim of this research work is a geochemical, mineralogical, and textural characterization of spontaneously smouldered coal-derived products in northwestern Venezuela (Cerro Pelado Formation, some
10 km from Pedregal city). Several solid samples were collected from this formation, six of unweathering
coal, an other six of resulting unmelted rocks forming on a surface coal bed, and the last four of mineralizations found accumulating around gas vents. The fresh coal and the unmelted material were analysed
by scanning electron microscopy, X-ray diffraction, and proximate techniques. Products such as magnetite and chabazite-K were identified in the alteration rocks. Likewise, both materials were also studied in
order to determine the mobilization of 17 elements into the environment; such elements were analysed
through inductively coupled plasma atomic emission spectroscopy on extracts obtained by a sequential
extraction method: each sample was firstly extracted with MilliQ water and then the resultant residue
was washed. This and the subsequently resulting residues are extracted according to the mentioned procedure by using, respectively, ammonium acetate, chlorhydric acid, peroxide and chlorhydric acid, nitric
acid and fluorhydric acid, and nitric acid. The studied elements are classified as highly mobile (Na, Ni, ...),
nearly immobile (Ti, P) and partially mobile (Mg, Fe, K,...). In regards to mineralizations around fumaroles
associated with smoldering coal seams, Fourier-transform infrared spectroscopy and X-ray diffraction
analyses have revealed the presence of salammoniac, mascagnite and other solid combustion compounds
formed by reaction of gas emitted from coal oxidation, in addition to previously non-reported sulfur-rich
by-products associated with gas fissures, particularly ammonium thiosulfate, a phase first obtained only
synthetically in the laboratory. Another objective of the research was to collect and analyse gases escaping from surficial vents. Relatively high concentrations of several aromatic compounds were detected in
the gas collected at the studied coal outcrop, as well as aliphatic hydrocarbons including ethane, propane,
butanes, among others. High contents of carbon monoxide, methane and carbon dioxide were also measured for gas samples
Eosinophilic esophagitis, celiac disease, and immunoglobulin E–mediated allergy in a 2-year-old child
This communication was presented at XXVI National
Congress of SEAIC, Spanish Society of Allergology and
Clinical Immunology, Bilbao, Spain, 2008Celiac disease, eosinophilic esophagitis, and urticaria are 3 manifestations of food allergy with different pathogenic mechanisms. We report
the case of a 2-year-old child with digestive symptoms, slow growth, and severe asthma. The results of skin prick tests were positive to
several foods. Endoscopy revealed eosinophilic esophagitis and celiac disease. Treatment consisted of a gluten-free diet and a 1-month
course of oral corticosteroids. Endoscopy and biopsy fi ndings were normal at 5 years of age.
A gluten-free diet is the basis of treatment of celiac disease, but the role of an elimination diet in eosinophilic esophagitis is not well
established. Our patient also developed urticaria when exposed to milk and egg. We present, to our knowledge, the fi rst report of a patient
with celiac disease, eosinophilic esophagitis, and immediate-type immunoglobulin E–mediated food allergyEnfermedad celíaca, esofagitis eosinofílica y urticaria son tres manifestaciones clínicas de alergia a alimentos con diferente etiopatogénesis.
Describimos el caso de una niña de 2 años de edad con síntomas digestivos, retraso del desarrollo póndero-estatural y asma persistente.
Las pruebas cutáneas fueron positivas a varios alimentos. La endoscopia digestiva y biopsias mostraron signos de esofagitis eosinofílica y
enfermedad celíaca. Realizó dieta exenta de gluten y de los alimentos a los que estaba sensibilizada y siguió tratamiento con corticoides
orales un mes. A los 5 años de edad, la endoscopia digestiva alta y biopsias esofágicas fueron normales.
Una dieta exenta de gluten es la base del tratamiento de la enfermedad celiaca. Sin embargo, el papel de las dietas de eliminación en
la esofagitis eosinofílica no ha sido totalmente establecido. La paciente desarrolló además urticaria tras contacto con leche y huevo.
Presentamos el primer caso de enfermedad celiaca, esofagitis eosinofi lica y alergia alimentaria mediada por IgE en el mismo pacient
Control de calidad del seguimiento del embarazo normal en atención primaria
ObjetivosGeneral: aumentar la calidad de la atención maternoinfantil en nuestra población.Específicomejorar al menos un 10% el registro de las actividades con peor cumplimiento en la primera evaluación del ciclo de calidad.DiseñoCiclo de calidad del programa de seguimiento de embarazo normal en atención primaria (AP).Dimensión de calidad estudiadacientífico-técnica. Evaluación retrospectiva, cruzada, por iniciativa interna y sobre las historias clínicas de las gestantes. Marco temporal: primera evaluación sobre gestaciones de 1994-1995; aplicación de medidas correctoras durante 1996; segunda evaluación sobre gestaciones de 1997-1998.ÁmbitoAtención primaria.SujetosTodas las gestaciones seguidas en nuestro equipo de AP durante los períodos descritos.Mediciones y resultados principalesCriterios evaluados: actividades asistenciales del programa de seguimiento del embarazo normal del Área 10.Primera evaluación (n = 54)incumplimiento global del 11,5%; los criterios con cumplimiento inferior al 80% fueron suplemento con ácido fólico, consejos a la gestante, detección de diabetes gestacional y visita al mes posparto Segunda evaluación (n = 69) incumplimiento global del 6,3%; todas las actividades superaron el 80% excepto la exploración obstétrica en la primera visita, la visita a la semana posparto y la visita al mes posparto.ConclusionesTras la introducción de unas medidas correctoras sencillas, logramos una mejoría global superior al 40% y un aumento en el cumplimiento de la mayor parte de las actividades, excepto en las visitas posparto y la exploración obstétrica en la primera visita. Creemos que es necesario mantener un ciclo continuo de mejora de calidad para conseguir una adecuada asistencia maternoinfantil.ObjectivesGeneral: to increase the quality of mother-baby care in our population. Specific: to improve by at least 10% the record of activities with poorest compliance at the first evaluation on the quality cycle.DesignQuality cycle of the normal pregnancy monitoring programme in primary care (PC). The scientific-technical dimension of quality was the one studied. There was a retrospective, crossed evaluation, on internal initiative, about the clinical records of the pregnant women. Sequence: first evaluation of pregnancies in 1994-95; application of corrective measures in 1996; second evaluation of pregnancies in 1997-98.SettingPrimary care.PatientsAll the pregnancies monitored by our PC team during the periods described.Measurements and main resultsCriteria evaluated: care activities of the programme for monitoring normal pregnancies in Area 10. First evaluation (n = 54): 11.5% overall non-compliance. The criteria with under 80% compliance were: folic acid supplement, counselling, diagnosis of pregnancy diabetes and attendance in the month after delivery. Second evaluation (n = 69): 6.3% overall non-compliance. All activities surpassed 80% compliance except obstetric examination on the first visit, attendance a week after delivery and attendance a month after delivery.ConclusionsAfter introducing certain simple corrective measures, we achieved overall improvement of over 40% and increased compliance in most activities, except for attendance after delivery and obstetric examination on the first visit. We think a continuous cycle of quality improvement needs to be maintained in order to achieve adequate mother-baby care
Body composition and somatotype in professional men's handball according to playing positions
Se realizó un estudio descriptivo transversal en 19 jugadores profesionales
del Club Balonmano Valladolid. Las mediciones antropométricas fueron
realizadas según el protocolo estándar. Se estimaron la masa grasa y ósea, se
calculó el somatotipo y se analizaron las diferencias entre las variables en
función de la posición.
Como resultados, se obtuvo que los pivotes fueron los jugadores más
pesados (con mayor porcentaje de masa grasa); los extremos, los más ligeros y
los laterales, junto con los pivotes, los más altos. No se observaron diferencias
en el IMC en los grupos. En la somatocarta los centrales y laterales se situaron
en la zona central; los extremos y los pivotes en la endomorfa-mesomorfa y los
porteros en la ecto-endomorfa.
Así se evidenció que las variables antropométricas, los datos de
composición corporal y la somatocarta de los deportistas confirman las
características morfológicas básicas de los jugadores para la posición para la
que son más aptosA cross-sectional descriptive study was accomplished in 19 professional players
from Valladolid Handball Club. Anthropometric measurements were performed
according to standard protocol. Body fat and bone mass were estimated, and
the somatotype was calculated.
As results, the line players were significantly the heaviest players; the wings
were lightest and the backs, with the line players, the tallest. Nevertheless, no
significant differences in BMI were observed. Regarding the body composition,
the line players showed the highest values of fat-mass. No differences in BMI
were observed in the groups. With respect to the somatochart, the center backs
and backs were in the central area; wings and line players showed an
endomorph-mesomorph development, and goalkeepers were in the ectoendomorph
area.
As conclusions, anthropometric variables, body composition data and the
somatochart of the athletes evaluated confirm the basic morphological
characteristics of the players for the position for which they are best suite
CEPA: A LaBr3(Ce)/LaCl3(Ce) phoswich array for simultaneous detection of protons and gamma radiation emitted in reactions at relativistic energies
4 pags.; 3 figs. ; this is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0This work was supported by the Spanish CICYT under the project numbers FPA2009-07387 andFPA2012-32443. J. Sánchez del Río thanks the ERANET NUPNET for the financial support via theproject GANAS.Peer Reviewe
The suppression of fluorescence peaks in energy-dispersive X-ray diffraction
A novel method to separate diffraction and fluorescence peaks in energy-
dispersive X-ray diffraction (EDXRD) is described. By tuning the excitation energy of an X-ray tube source to just below an elemental absorption edge, the corresponding fluorescence peaks of that element are completely suppressed in the resulting spectrum. Since Bremsstrahlung photons are present in the source spectrum up to the excitation energy, any diffraction peaks that lie at similar energies to the suppressed fluorescence peaks are uncovered. This technique is an alternative to the more usual method in EDXRD of altering the scattering angle in order to shift the energies of the diffraction peaks. However, in the back-reflection EDXRD technique [Hansford (2011). J. Appl. Cryst. 44, 514–525] changing the scattering angle would lose the unique property of insensitivity to sample morphology and is therefore an unattractive option. The use of fluorescence suppression to reveal diffraction peaks is demonstrated experimentally by suppressing the Ca K fluorescence peaks in the back-reflection EDXRD spectra of several limestones and dolomites. Three substantial benefits are derived: uncovering of diffraction peak(s) that are otherwise obscured by fluorescence; suppression of the Ca K escape peaks; and an increase in the signal-to-background ratio. The improvement in the quality of the EDXRD spectrum allows the identification of a secondary mineral in the samples, where present. The results for a pressed-powder pellet of the geological standard JDo-1 (dolomite) show the presence of crystallite preferred orientation in this prepared sample. Preferred orientation is absent in several unprepared limestone and dolomite rock specimens, illustrating an advantage of the observation of rocks in their natural state enabled by back-reflection EDXRD
Multiple high-risk HPV genotypes are grouped by type and are associated with viral load and risk factors
Investigating whether high-risk human papillomavirus (HR-HPV) types tend to become grouped in a particular way and whether factors are associated with such grouping is important for measuring the real impact of vaccination. In total, 219 women proving positive for HPV as detected by real-time PCR were included in the study. Each sample was analysed for detecting and quantifying six viral types and the hydroxymethylbilane synthase gene. Multiple correspondence analysis led to determining grouping patterns for six HR-HPV types and simultaneous association with multiple variables and whether viral load was related to the coexistence of other viral types. Two grouping profiles were identified: the first included HPV-16 and HPV-45 and the second profile was represented by HPV-31, HPV-33 and HPV-58. Variables such as origin, contraceptive method, births and pregnancies, educational level, healthcare affiliation regime, atypical squamous cells of undetermined significance and viral load were associated with these grouping profiles. Different socio-demographic characteristics were found when coinfection occurred by phylogenetically related HPV types and when coinfection was due to non-related types. Biological characteristics, the number of viral copies, temporality regarding acquiring infection and competition between viral types could influence the configuration of grouping patterns. Characteristics related to women and HPV, influence such interactions between coexisting HPV types reflecting the importance of their evaluation. Copyright © Cambridge University Press 2017
- …