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1.
Appl Opt ; 63(10): 2737-2745, 2024 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-38568559

RESUMEN

We investigate the generation of an elliptical perfect optical vortex (EPOV) beam through the optical Fourier transformation of an elliptical Bessel-Gaussian beam and derive an analytical expression for its complex field amplitude. Our analysis includes the examination of the beam's propagation in free-space and the influence of topological charge on its transmission. The EPOV beam's propagation in free-space can be categorized into non-diffracting and diffracting stages. During the non-diffracting stage, the beam intensity and profile size are effectively preserved over a short transmission distance. Subsequently, in the diffracting stage, the beam profile initially contracts and then expands with a change in the beam intensity. Notably, the impact of topological charge on the beam intensity and profile size varies across different stages of propagation. We compare our results with those of the circular perfect optical vortex beam propagating in free-space, observing that the EPOV beam exhibits non-diffracting behavior for short propagation distances compared to its circular counterpart. The signature of the focusing behavior of the EPOV beam is observed at a relatively small propagation distance compared to the circular case.

2.
J Phys Chem Lett ; 14(26): 6061-6070, 2023 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-37358397

RESUMEN

XUV photoelectron spectroscopy (XPS) is a powerful method for investigating the electronic structures of molecules. However, the correct interpretation of results in the condensed phase requires theoretical models that account for solvation. Here we present experimental aqueous-phase XPS of two organic biomimetic molecular switches, NAIP and p-HDIOP. These switches are structurally similar, but have opposite charges and thus present a stringent benchmark for solvation models which need to reproduce the observed ΔeBE = 1.1 eV difference in electron binding energy compared to the 8 eV difference predicted in the gas phase. We present calculations using implicit and explicit solvent models. The latter employs the average solvent electrostatic configuration and free energy gradient (ASEC-FEG) approach. Both nonequilibrium polarizable continuum models and ASEC-FEG calculations give vertical binding energies in good agreement with the experiment for three different computational protocols. Counterions, explicitly accounted for in ASEC-FEG, contribute to the stabilization of molecular states and reduction of ΔeBE upon solvation.

3.
Ecol Appl ; 32(8): e2707, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-35808937

RESUMEN

Arthropod biomass is a key element in ecosystem functionality and a basic food item for many species. It must be estimated through traditional costly field sampling, normally at just a few sampling points. Arthropod biomass and plant productivity should be narrowly related because a large majority of arthropods are herbivorous, and others depend on these. Quantifying plant productivity with satellite or aerial vehicle imagery is an easy and fast procedure already tested and implemented in agriculture and field ecology. However, the capability of satellite or aerial vehicle imagery for quantifying arthropod biomass and its relationship with plant productivity has been scarcely addressed. Here, we used unmanned aerial vehicle (UAV) and satellite Sentinel-2 (S2) imagery to establish a relationship between plant productivity and arthropod biomass estimated through ground-truth field sampling in shrub steppes. We UAV-sampled seven plots of 47.6-72.3 ha at a 4-cm pixel resolution, subsequently downscaling spatial resolution to 50 cm resolution. In parallel, we used S2 imagery from the same and other dates and locations at 10-m spatial resolution. We related several vegetation indices (VIs) with arthropod biomass (epigeous, coprophagous, and four functional consumer groups: predatory, detritivore, phytophagous, and diverse) estimated at 41-48 sampling stations for UAV flying plots and in 67-79 sampling stations for S2. VIs derived from UAV were consistently and positively related to all arthropod biomass groups. Three out of seven and six out of seven S2-derived VIs were positively related to epigeous and coprophagous arthropod biomass, respectively. The blue normalized difference VI (BNDVI) and enhanced normalized difference VI (ENDVI) showed consistent and positive relationships with arthropod biomass, regardless of the arthropod group or spatial resolution. Our results showed that UAV and S2-VI imagery data may be viable and cost-efficient alternatives for quantifying arthropod biomass at large scales in shrub steppes. The relationship between VI and arthropod biomass is probably habitat-dependent, so future research should address this relationship and include several habitats to validate VIs as proxies of arthropod biomass.


Asunto(s)
Artrópodos , Animales , Biomasa , Ecosistema , Pradera , Dispositivos Aéreos No Tripulados , Plantas
4.
Phys Rev Lett ; 127(19): 192501, 2021 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-34797155

RESUMEN

The changes in the mean-square charge radius (relative to ^{209}Bi), magnetic dipole, and electric quadrupole moments of ^{187,188,189,191}Bi were measured using the in-source resonance-ionization spectroscopy technique at ISOLDE (CERN). A large staggering in radii was found in ^{187,188,189}Bi^{g}, manifested by a sharp radius increase for the ground state of ^{188}Bi relative to the neighboring ^{187,189}Bi^{g}. A large isomer shift was also observed for ^{188}Bi^{m}. Both effects happen at the same neutron number, N=105, where the shape staggering and a similar isomer shift were observed in the mercury isotopes. Experimental results are reproduced by mean-field calculations where the ground or isomeric states were identified by the blocked quasiparticle configuration compatible with the observed spin, parity, and magnetic moment.

5.
Rev Sci Instrum ; 91(10): 103002, 2020 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-33138596

RESUMEN

The In-Gas-jet Laser Ionization and Spectroscopy (IGLIS) technique relies on narrow-bandwidth, high-peak-power, short-pulse-length (≈10 ns), and high-repetition-rate laser pulses to probe, precisely and efficiently, the hyperfine structure of medium-heavy and heavy isotopes, embedded in a supersonic jet. The power and repetition rate requirements of the laser system are met by combining ≈100 W, 8 ns pulse width, 10 kHz commercial Nd:YAG pump lasers with a single-mode continuous wave seeded Pulsed Dye Amplifier (PDA). The common multi-longitudinal-mode operation of these Nd:YAG pump lasers causes, however, undesirable frequency sidebands in the output spectrum of the PDA system, hindering the attainable spectral resolution, a correct interpretation, and an accurate analysis of the hyperfine spectra. In this article, a new prototype Nd:YAG laser is presented, which combined with the PDA system is capable of providing quasi-transform-limited laser pulses at 10 kHz, with only limited losses in laser power. This system reduces any spectral sideband amplitude below a proven upper limit of 0.2% with one order of magnitude extra reduction expected based on simulations. A full characterization of both the Nd:YAG and PDA laser systems is done by studying the temporal and frequency behavior in detail. This study is finalized by a performance benchmark of this combined laser system in the hyperfine spectroscopy of copper isotopes, showcasing its applicability for future IGLIS studies.

6.
Rev. esp. anestesiol. reanim ; 67(9): 511-515, nov. 2020. ilus
Artículo en Español | IBECS | ID: ibc-194384

RESUMEN

Describimos el caso de una gestante de 24 años de edad, sin enfermedades previas, que fue ingresada con diagnóstico de neumonía bilateral por el nuevo coronavirus 2. Por empeoramiento clínico precisó cesárea urgente con anestesia general e intubación orotraqueal por intolerancia al decúbito. Tras la extubación desarrolló un cuadro de obnubilación que obligó al diagnóstico diferencial de encefalitis/meningitis por SARS-CoV-2, con tomografía computarizada (TC) y angioTC normales, bioquímica del líquido cefalorraquídeo (LCR) inespecífica y resonancia magnética informada como «síndrome de encefalopatía posterior reversible» (al presentar características radiológicas sugestivas de edema vasogénico con alteraciones en la sustancia blanca de localización parieto-temporo-occipital, junto con alteración de nivel de conciencia) secundaria a cuadro hipertensivo del embarazo. La paciente 11 días después de la cesárea comenzó a desarrollar un cuadro hipertensivo que requirió tratamiento. La encefalopatía posterior reversible (PRES) asocia un conjunto de características clínicas (cefalea, alteración del nivel de conciencia, alteraciones visuales y convulsiones) y radiológicas (alteraciones reversibles en la sustancia blanca fundamentalmente en regiones parieto-temporo-occipitales) sugestivas de edema vasogénico. En pacientes gestantes SARS-CoV-2, el diagnóstico diferencial de la patología hipertensiva y las alteraciones de nivel de conciencia puede ser extremadamente complicado, al encontrarnos pruebas complementarias normales y ausencia de hipertensión arterial (HTA) en el periparto inmediato. Tal vez la secuenciación del genoma del SARS-CoV-2 en el LCR nos hubiera permitido un diagnóstico de certeza, aunque el tratamiento no hubiera variado


We describe the case of a 24-year-old pregnant woman with no history of note who was admitted with a diagnosis of bilateral pneumonia caused by the new coronavirus. Due to clinical worsening, she required urgent cesarean section with general anaesthesia and intubation for decubitus intolerance. After extubation, she presented altered mental state that required a differential diagnosis of encephalitis/meningitis secondary to SARS-CoV-2. CT and CT-angiography were normal, spinal fluid tests were non-specific, and magnetic resonance imaging reported posterior reversible encephalopathy syndrome (PRES) (due to radiological features suggestive of white matter vasogenic edema affecting the parietal, temporal and occipital lobes, along with altered mental state) secondary to gestational hypertension. Eleven days after the cesarean section the patient began to develop hypertension that required treatment. PRES is associated with certain clinical (headache, altered mental state, visual disturbances and convulsions) and radiological (reversible changes in white substance mainly affecting the parietal, temporal, and occipital lobes) characteristics suggestive of vasogenic oedema In pregnant SARS-CoV-2 patients, the differential diagnosis of hypertension and altered mental state is often extremely complicated because complementary tests can be normal and there is no immediate sign of peripartum hypertension. SARS-CoV-2 genome sequencing in spinal fluid could have provided a definitive diagnosis, but the treatment would not have differed


Asunto(s)
Humanos , Femenino , Embarazo , Adulto Joven , Encefalopatías/virología , Infecciones por Coronavirus/complicaciones , Coronavirus Relacionado al Síndrome Respiratorio Agudo Severo/patogenicidad , Trastornos de la Conciencia/virología , Neumonía Viral/complicaciones , Trastornos Puerperales/virología , Factores de Riesgo , Complicaciones Infecciosas del Embarazo/virología , Diagnóstico Diferencial , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
7.
Rev Esp Anestesiol Reanim (Engl Ed) ; 67(9): 511-515, 2020 Nov.
Artículo en Inglés, Español | MEDLINE | ID: mdl-33036761

RESUMEN

We describe the case of a 24-year-old pregnant woman with no history of note who was admitted with a diagnosis of bilateral pneumonia caused by the new coronavirus. Due to clinical worsening, she required urgent cesarean section with general anaesthesia and intubation for decubitus intolerance. After extubation, she presented altered mental state that required a differential diagnosis of encephalitis/meningitis secondary to SARS-CoV-2. CT and CT-angiography were normal, spinal fluid tests were non-specific, and magnetic resonance imaging reported posterior reversible encephalopathy syndrome (PRES) (due to radiological features suggestive of white matter vasogenic edema affecting the parietal, temporal and occipital lobes, along with altered mental state) secondary to gestational hypertension. Eleven days after the cesarean section the patient began to develop hypertension that required treatment. PRES is associated with certain clinical (headache, altered mental state, visual disturbances and convulsions) and radiological (reversible changes in white substance mainly affecting the parietal, temporal, and occipital lobes) characteristics suggestive of vasogenic oedema In pregnant SARS-CoV-2 patients, the differential diagnosis of hypertension and altered mental state is often extremely complicated because complementary tests can be normal and there is no immediate sign of peripartum hypertension. SARS-CoV-2 genome sequencing in spinal fluid could have provided a definitive diagnosis, but the treatment would not have differed.


Asunto(s)
Betacoronavirus , Infecciones por Coronavirus/complicaciones , Neumonía Viral/complicaciones , Síndrome de Leucoencefalopatía Posterior/etiología , Complicaciones Infecciosas del Embarazo , Trastornos Puerperales/etiología , COVID-19 , Prueba de COVID-19 , Técnicas de Laboratorio Clínico , Trastornos de la Conciencia/diagnóstico por imagen , Trastornos de la Conciencia/etiología , Infecciones por Coronavirus/diagnóstico , Infecciones por Coronavirus/diagnóstico por imagen , Diagnóstico Diferencial , Femenino , Humanos , Imagen por Resonancia Magnética , Pandemias , Neumonía Viral/diagnóstico por imagen , Síndrome de Leucoencefalopatía Posterior/diagnóstico por imagen , Embarazo , Trastornos Puerperales/diagnóstico por imagen , SARS-CoV-2 , Adulto Joven
8.
Rev Calid Asist ; 32(5): 248-254, 2017.
Artículo en Español | MEDLINE | ID: mdl-28863966

RESUMEN

BACKGROUND AND OBJECTIVES: It has been shown that patients admitted to hospital during the weekends tend to have less favourable outcomes, including higher mortality rates, compared with those admitted during weekdays. The main objective of this study is to evaluate the impact of on the health outcomes of patients admitted during the weekend. MATERIAL AND METHODS: A retrospective observational study was conducted on all patients admitted to Montilla Hospital (Córdoba).. All hospitalised patients were attended to daily, including weekends and holidays. An analysis was performed on the epidemiological variables and health outcomes (total mortality). RESULTS: The study included a total of 2,565 hospital admissions, of whom 653 (25.6%) were discharged during the weekend. Patients discharged during the weekend were significantly younger [53 (27) versus 56 (27) years, P<.002], had fewer diagnoses on discharge [6.2 (3.7) versus 6.7 (3.9), P<.003], and had fewer procedures performed [(3 (1.9) versus 3.2 (1.8), P<.005]. The mean length of stay was shorter for weekend discharges than the weekday discharges [3 (2.6) days versus 3.7 (3.9) days, P<.001). The total mortality was 4%, and there were no differences between weekday and weekend admissions (4.3% versus 3.7%). Home discharges on the weekend were related to a reduction in the mean length of stay by 0.3 days (from 3.6 to 3.9 days, P<.001). CONCLUSIONS: Hospitalised patient care has led to the disappearance of increased mortality during weekends.


Asunto(s)
Vacaciones y Feriados , Mortalidad Hospitalaria , Hospitalización/estadística & datos numéricos , Adulto , Anciano , Áreas de Influencia de Salud , Grupos Diagnósticos Relacionados , Femenino , Vacaciones y Feriados/estadística & datos numéricos , Departamentos de Hospitales , Hospitales Públicos/estadística & datos numéricos , Humanos , Tiempo de Internación/estadística & datos numéricos , Masculino , Persona de Mediana Edad , Admisión del Paciente/estadística & datos numéricos , Alta del Paciente/estadística & datos numéricos , Estudios Retrospectivos , España , Factores de Tiempo , Resultado del Tratamiento
9.
Nat Commun ; 8: 14520, 2017 02 22.
Artículo en Inglés | MEDLINE | ID: mdl-28224987

RESUMEN

Resonant laser ionization and spectroscopy are widely used techniques at radioactive ion beam facilities to produce pure beams of exotic nuclei and measure the shape, size, spin and electromagnetic multipole moments of these nuclei. However, in such measurements it is difficult to combine a high efficiency with a high spectral resolution. Here we demonstrate the on-line application of atomic laser ionization spectroscopy in a supersonic gas jet, a technique suited for high-precision studies of the ground- and isomeric-state properties of nuclei located at the extremes of stability. The technique is characterized in a measurement on actinium isotopes around the N=126 neutron shell closure. A significant improvement in the spectral resolution by more than one order of magnitude is achieved in these experiments without loss in efficiency.

10.
Spinal Cord ; 54(12): 1152-1157, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27401127

RESUMEN

STUDY DESIGN: This is a comparative study between players with and without spinal cord injury (SCI) during a training task. OBJECTIVE: This study examined physiological responses in commonly used small-sided games (SSGs) in well-experienced wheelchair basketball (WB) players with SCI and without SCI (Non-SCI). SETTING: The study was conducted with a WB team in Vitoria-Gasteiz, Spain (2014). METHODS: The team was divided into an SCI group (n=6) and a Non-SCI group (n=6). Absolute and relative heart rate (HR) along with tympanic temperature and perceived exertion (RPE) were recorded for both groups. RESULTS: The two groups attained different absolute HR values for the same SSG. However, no significant differences were observed in relative HR between groups (%HRmean, %HRpeak and the percentage of the time spent in each HR zone: low, moderate, high and maximal) nor in tympanic temperature. Moreover, in relation to the bout evolution analysis (4 repetitions of 4 min), the Non-SCI group significantly increased (P<0.05) absolute HRmean and HRpeak during bouts, whereas the SCI group maintained them constant. Furthermore, the variations in the percentage of the time spent in each HR zone only were observed in the Non-SCI group. CONCLUSION: In spite of the Non-SCI group attaining higher absolute HR values, the SCI and Non-SCI groups may have similar HR relative values during a specific WB training task. However, the SCI group reported significantly higher values in respiratory RPE in the last bout than the Non-SCI group for the same SSG.


Asunto(s)
Baloncesto/fisiología , Traumatismos de la Médula Espinal/fisiopatología , Silla de Ruedas , Adolescente , Adulto , Temperatura Corporal/fisiología , Frecuencia Cardíaca/fisiología , Humanos , Percepción , Respiración , Membrana Timpánica/fisiopatología
11.
Int J Sports Med ; 37(7): 539-46, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-27116348

RESUMEN

This study aimed to predict the velocity corresponding to the maximal lactate steady state (MLSSV) from non-invasive variables obtained during a maximal multistage running field test (modified University of Montreal Track Test, UMTT), and to determine whether a single constant velocity test (CVT), performed several days after the UMTT, could estimate the MLSSV. Within 4-5 weeks, 20 male runners performed: 1) a modified UMTT, and 2) several 30 min CVTs to determine MLSSV to a precision of 0.25 km·h(-1). Maximal aerobic velocity (MAV) was the best predictor of MLSSV. A regression equation was obtained: MLSSV=1.425+(0.756·MAV); R(2)=0.63. Running velocity during the CVT (VCVT) and blood lactate at 6 (La6) and 30 (La30) min further improved the MLSSV prediction: MLSSV=VCVT+0.503 - (0.266·ΔLa30-6); R(2)=0.66. MLSSV can be estimated from MAV during a single maximal multistage running field test among a homogeneous group of trained runners. This estimation can be further improved by performing an additional CVT. In terms of accuracy, simplicity and cost-effectiveness, the reported regression equations can be used for the assessment and training prescription of endurance runners.


Asunto(s)
Ácido Láctico/sangre , Carrera/fisiología , Adulto , Prueba de Esfuerzo , Frecuencia Cardíaca , Humanos , Masculino , Resistencia Física
12.
Anim Reprod Sci ; 168: 50-56, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-26949140

RESUMEN

Artificial lights are essential for controlling the reproductive tract development of birds during puberty and therefore influence reproductive quality. The aim of this study was to evaluate the effect of different light sources on reproductive anatomic and physiological characteristics of female Japanese quail (Coturnix coturnix japonica). A total of 270 birds from one day of age were housed in a masonry shed divided into six rooms with light isolation. Each room was equipped with a different type of light bulb and contained seven cages with five birds in each. The light bulbs tested were: incandescent; compact fluorescent; and light-emitting diode (LED) in the colors white, blue, red and green. The experimental design was completely randomized with six treatments and seven replications of individual birds each. The anatomic and physiological condition of the birds was evaluated at four, eight and 12 weeks of age. The white LED bulb advanced (P<0.05) the sexual maturity by one week, resulted (P<0.05) in higher live weights and greater weight and relative percentage of ovarian stroma, oviduct and ovarian tissue at eight weeks of age. Higher plasma concentrations of estradiol and lipids were also observed (P<0.05) at eight weeks under the white LED bulb. At 12 weeks of age, the magnum and isthmus folding characteristics were better (P<0.05) with the red LED bulb. In conclusion, the photostimulation with the white LED bulb was more efficient at activating the reproductive cycle, hastening the onset of sexual maturity and increasing the development of reproductive organs after puberty.


Asunto(s)
Coturnix/anatomía & histología , Luz , Animales , Color , Coturnix/fisiología , Femenino , Genitales Femeninos/anatomía & histología , Genitales Femeninos/crecimiento & desarrollo , Genitales Femeninos/fisiología , Genitales Femeninos/efectos de la radiación , Ovario/crecimiento & desarrollo , Ovario/efectos de la radiación , Oviductos/crecimiento & desarrollo , Oviductos/efectos de la radiación , Maduración Sexual/efectos de la radiación
13.
Biol Sport ; 32(1): 71-8, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25729153

RESUMEN

The aims of the present study were, firstly, to determine the reliability and reproducibility of an agility T-test and Yo-Yo 10 m recovery test; and secondly, to analyse the physical characteristics measured by sprint, agility, strength and endurance field tests in wheelchair basketball (WB) players. 16 WB players (33.06 ± 7.36 years, 71.89 ± 21.71 kg and sitting body height 86.07 ± 6.82 cm) belonging to the national WB league participated in this study. Wheelchair sprint (5 and 20 m without ball, and 5 and 20 m with ball) agility (T-test and pick-up test) strength (handgrip and maximal pass) and endurance (Yo-Yo 10 m recovery test) were performed. T-test and Yo-Yo 10 m recovery test showed good reproducibility values (intraclass correlation coefficient, ICC = 0.74-0.94). The WB players' results in 5 and 20 m sprints without a ball were 1.87 ± 0.21 s and 5.70 ± 0.43 s and with a ball 2.10 ± 0.30 s and 6.59 ± 0.61 s, being better than those reported in the literature. Regarding the pick-up test results (16.05 ± 0.52 s) and maximal pass (8.39 ± 1.77 m), players showed worse values than those obtained in elite players. The main contribution of the present study is the characterization of the physical performance profile of WB players using a field test battery. Furthermore, we demonstrated that the agility T-test and the aerobic Yo-Yo 10 m recovery test are reliable; consequently they may be appropriate instruments for measuring physical fitness in WB.

14.
J Sports Med Phys Fitness ; 54(5): 553-8, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25270774

RESUMEN

AIM: The main purpose of this study was to investigate if the lactate threshold estimated by the maximal deviation method (LTDmax) and the onset of blood lactate accumulation speed (LTOBLA) are good correlates of middle- and long-distance running performance in well-trained endurance runners. METHODS: Eleven long- and eleven middle-distance runners participated in this study. All participants completed a maximal incremental running test on a treadmill to determine maximal physiological variables and velocities corresponding to LTDmax and LTOBLA (4 mmol·L-1 of lactate concentration). The relationships between LTDmax, LTOBLA and the best 10-km (S10km) and 3-km (S3km) race pace were analyzed in the long- and middle distance runners, respectively. RESULTS: The velocities for LTDmax and LTOBLA were 17.0±0.7 km·h-1 and 17.5±1.3 km·h-1 for the long-distance runners and 16.9±1.1 km·h-1 and 17.4±1.3 km·h-1 for the middle-distance runners. A positive linear relationship was found between LTDmax and S10km (r=0.873, P<0.001), as well as between LTOBLA and S10km (r=0.919, P<0.001) in the long-distance runners. Similarly, LTDmax and LTOBLA were significantly correlated with S3km in the middle-distance runners (r=0.825, P<0.01 and r=0.849, P<0.001, respectively). CONCLUSION: These results indicate that both LTOBLA and LTDmax are highly associated to running performance according to S10km and S3km in well-trained long- and middle-distance runners. Thus, we conclude that competitive middle- and long-distance athletes may find these measures useful to monitor running performance within 3 weeks of laboratory testing.


Asunto(s)
Ácido Láctico/sangre , Resistencia Física/fisiología , Carrera/fisiología , Adulto , Umbral Anaerobio/fisiología , Femenino , Humanos , Masculino , Consumo de Oxígeno/fisiología , Educación y Entrenamiento Físico
15.
Int J Sports Med ; 35(13): 1118-23, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24977947

RESUMEN

This study aimed to investigate the relationship between stride angle and running economy (RE) in athletes with different foot strike patterns. 30 male runners completed 4 min running stages on a treadmill at different velocities. During the test, biomechanical variables such as stride angle, swing time, contact time, stride length and frequency were recorded using an optical measurement system. Their foot strike pattern was determined, and VO2 at velocities below the lactate threshold were measured to calculate RE. Midfoot/forefoot strikers had better RE than rearfoot strikers (201.5±5.6 ml · kg(-1) · km(-1) vs. 213.5±4.2 ml · kg(-1) · km(-1)respectively; p=0.019). Additionally, midfoot/fore-foot strikers presented higher stride angles than rearfoot strikers (p=0.043). Linear modelling analysis showed that stride angle is closely related to RE (r=0.62, p<0.001) and that the effect of stride angle on RE was different in the 2 groups. From an arbitrary value of 4°, a rearfoot strike pattern is likely to be more economical, whereas at any lower degree, the midfoot/forefoot strike pattern appears to be more desirable. A biomechanical running technique characterised by high stride angles and a midfoot/forefoot strike pattern is advantageous for a better RE. Athletes may find stride angle useful for improving RE.


Asunto(s)
Pie/fisiología , Marcha/fisiología , Carrera/fisiología , Adulto , Umbral Anaerobio , Fenómenos Biomecánicos , Humanos , Masculino
16.
Biol Sport ; 30(3): 181-7, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24744486

RESUMEN

The purpose of this study was to investigate the relationship between biomechanical variables and running economy in North African and European runners. Eight North African and 13 European male runners of the same athletic level ran 4-minute stages on a treadmill at varying set velocities. During the test, biomechanical variables such as ground contact time, swing time, stride length, stride frequency, stride angle and the different sub-phases of ground contact were recorded using an optical measurement system. Additionally, oxygen uptake was measured to calculate running economy. The European runners were more economical than the North African runners at 19.5 km · h(-1), presented lower ground contact time at 18 km · h(-1) and 19.5 km · h(-1) and experienced later propulsion sub-phase at 10.5 km · h(-1),12 km · h(-1), 15 km · h(-1), 16.5 km · h(-1) and 19.5 km · h(-1) than the European runners (P < 0.05). Running economy at 19.5 km · h(-1) was negatively correlated with swing time (r = -0.53) and stride angle (r = -0.52), whereas it was positively correlated with ground contact time (r = 0.53). Within the constraints of extrapolating these findings, the less efficient running economy in North African runners may imply that their outstanding performance at international athletic events appears not to be linked to running efficiency. Further, the differences in metabolic demand seem to be associated with differing biomechanical characteristics during ground contact, including longer contact times.

17.
Int J Sports Med ; 30(8): 614-23, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19382055

RESUMEN

This study examined the effects of heavy resistance training on dynamic exercise-induced fatigue task (5 x 10RM leg-press) after two loading protocols with the same relative intensity (%) (5 x 10RM(Rel)) and the same absolute load (kg) (5 x 10RM(Abs)) as in pretraining in men (n=12). Maximal strength and muscle power, surface EMG changes [amplitude and spectral indices of muscle fatigue], and metabolic responses (i.e.blood lactate and ammonia concentrations) were measured before and after exercise. After training, when the relative intensity of the fatiguing dynamic protocol was kept the same, the magnitude of exercise-induced loss in maximal strength was greater than that observed before training. The peak power lost after 5 x 10RM(Rel) (58-62%, pre-post training) was greater than the corresponding exercise-induced decline observed in isometric strength (12-17%). Similar neural adjustments, but higher accumulated fatigue and metabolic demand were observed after 5 x 10RM(Rel). This study therefore supports the notion that similar changes are observable in the EMG signal pre- and post-training at fatigue when exercising with the same relative load. However, after training the muscle is relatively able to work more and accumulate more metabolites before task failure. This result may indicate that rate of fatigue development (i.e. power and MVC) was faster and more profound after training despite using the same relative intensity.


Asunto(s)
Adaptación Fisiológica/fisiología , Tolerancia al Ejercicio/fisiología , Contracción Isométrica/fisiología , Fatiga Muscular/fisiología , Músculo Esquelético/fisiología , Entrenamiento de Fuerza , Adulto , Amoníaco/sangre , Análisis de Varianza , Demografía , Electromiografía , Potenciales Evocados Motores , Humanos , Ácido Láctico/sangre , Estudios Longitudinales , Masculino , Fuerza Muscular , Músculo Esquelético/inervación , Factores de Tiempo
18.
Mol Phylogenet Evol ; 49(2): 554-60, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-18725307

RESUMEN

Phylogenetic relationships of symbiotic dinoflagellate lineages, distributed in all tropical and subtropical seas, suggest strategies for long distance dispersal but at the same time strong host specialization. Zooxanthellae (Symbiodinium: Dinophyta), which are associated to diverse shallow-water cnidarians, also engage in symbioses with some sponge species of the genus Cliona. In the Caribbean, zooxanthellae-bearing Cliona has recently become abundant due to global warming, overfishing, and algae abundance. Using molecular techniques, the symbionts from five excavating species (Clionacaribbaea, C. tenuis, C. varians, C. aprica and C. laticavicola) from the southern and southwestern Caribbean were surveyed. Several DNA sequence regions were used in order to confirm zooxanthellae identity; 18S rDNA, domain V of chloroplast large subunit (cp23S), internal transcribed spacer 2 (ITS2), and ITS2 secondary structure. Sequence analyses corroborated the presence of three zooxanthellae clades: A, B, and G. Presence of clades A and B in common boring sponges of the Caribbean fit with the general pattern of the province. The discovery of clade G for the first time in any organism of the Atlantic Ocean leads us to consider this unusual finding as a phylogenetic relict through common ancestors of sponge clades or an invasion of the sponge from the Indo-Pacific.


Asunto(s)
Dinoflagelados/clasificación , Dinoflagelados/genética , Filogenia , Poríferos/fisiología , Simbiosis , Animales , Teorema de Bayes , Región del Caribe , ADN de Cloroplastos/genética , ADN Protozoario/genética , ADN Espaciador Ribosómico/genética , Evolución Molecular , Funciones de Verosimilitud , ARN Ribosómico 18S/genética , Alineación de Secuencia , Análisis de Secuencia de ADN
19.
Int J Sports Med ; 28(10): 860-7, 2007 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-17497580

RESUMEN

This study compared physical characteristics (body height [BH], body mass [BM], body fat [BF], and fat free mass [FFM]), one repetition maximum bench press (1RM (BP)), jumping explosive power (VJ), handball throwing velocity, power-load relationship of the leg and arm extensor muscles, 5- and 15-m sprint running time, and running endurance in elite (n = 16; EF) and amateur (n = 15; AF) female handball players aged 17 - 38. Results revealed that, compared to AF, EF players presented similar values in body mass and percent body fat, but higher values (p < 0.001 - 0.05) in BH (6 %), FFM (10 %), 1RM (BP) (23 %), VJ (10 %), handball throwing velocity (11 %), power-load relationship of the arm (25 %) and leg (12 %) extensors, as well as 5- and 15-m sprint (3 - 4 %) and endurance running velocities (13 %). Univariate regression analyses showed that 1RM (BP) was associated with throwing velocity (R (2) = 0.64). The higher absolute values of maximal strength and muscle power, although explained by the differences in fat free mass, will give EF an advantage to sustain certain handball game actions. The association between 1RM (BP) and throwing velocity suggests that throwing velocity values in female handball players depend more on maximal strength than on the capacity to move low loads at high velocities, during elbow extension actions.


Asunto(s)
Antropometría , Aptitud Física/fisiología , Deportes/fisiología , Adolescente , Adulto , Índice de Masa Corporal , Prueba de Esfuerzo , Femenino , Humanos , Fuerza Muscular , Resistencia Física , Carrera , España
20.
Cochrane Database Syst Rev ; (2): CD004979, 2006 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-16625618

RESUMEN

BACKGROUND: Acute respiratory infection (ARI) is one of the leading causes of morbidity and mortality in children under five years of age in developing countries. When hospitalisation is required, the usual practice includes administering parenteral antibiotics if a bacterial infection is suspected. This has disadvantages as it causes pain and discomfort to the children, which may lead to treatment refusal or reduced compliance. It is also associated with needle-related complications. In some settings this equipment is in short supply or unavailable necessitating transfer of the child, which increases risks and healthcare costs. OBJECTIVES: To determine the equivalence in effectiveness and safety of oral antibiotic compared to parenteral antibiotic therapies in the treatment of severe pneumonia in children between three months and five years of age. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2005); MEDLINE (January 1966 to July 2005); EMBASE (January 1990 to July 2005) and LILACS (February 2005). SELECTION CRITERIA: The review included published or unpublished randomised controlled trials (RCTs) and quasi-RCTs comparing any oral antibiotic therapy with any parenteral antibiotic therapy for the treatment of severe pneumonia in children from three months to five years of age. DATA COLLECTION AND ANALYSIS: The search yielded more than 1300 titles. Only three studies met all criteria for eligibility. One of the identified trials is yet to publish its results. We did not perform a meta-analysis because of clinical heterogeneity of therapies compared in the included trials. MAIN RESULTS: Campbell 1988 compared oral co-trimoxazole versus intramuscular procaine penicillin followed by oral ampicillin in 134 children. At the seventh day of follow up, treatment failure occurred in 6/66 (9.1%) in the oral co-trimoxazole group and 7/68 (10.2%) in the combined-treatment group. The risk difference was -0.01% (95% confidence interval (CI) -0.11 to 0.09). The APPIS Group 2004 evaluated 1702 patients comparing oral amoxicillin versus intravenous penicillin for two days followed by oral amoxicillin. After 48 hours, treatment failure occurred in 161/845 (19%) in the amoxicillin group and 167/857 (19%) in the parenteral penicillin group. The risk difference was -0.4% (95% CI -4.2 to 3.3). The authors reported similar recovery in both groups at 5 and 14 days. AUTHORS' CONCLUSIONS: Oral therapy appears to be an effective and safe alternative to parenteral antibiotics in hospitalised children with severe pneumonia who do not have any serious signs or symptoms.


Asunto(s)
Antibacterianos/administración & dosificación , Neumonía/tratamiento farmacológico , Administración Oral , Ampicilina/administración & dosificación , Preescolar , Humanos , Lactante , Inyecciones Intramusculares , Penicilina G Procaína/administración & dosificación , Ensayos Clínicos Controlados Aleatorios como Asunto , Combinación Trimetoprim y Sulfametoxazol/administración & dosificación
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