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1.
Phys Rev Lett ; 118(14): 144503, 2017 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-28430520

RESUMEN

We investigate experimentally the statistical properties of a wind-generated wave field and the spontaneous formation of rogue waves in an annular flume. Unlike many experiments on rogue waves where waves are mechanically generated, here the wave field is forced naturally by wind as it is in the ocean. What is unique about the present experiment is that the annular geometry of the tank makes waves propagating circularly in an unlimited-fetch condition. Within this peculiar framework, we discuss the temporal evolution of the statistical properties of the surface elevation. We show that rogue waves and heavy-tail statistics may develop naturally during the growth of the waves just before the wave height reaches a stationary condition. Our results shed new light on the formation of rogue waves in a natural environment.

2.
Data Brief ; 48: 109105, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37095754

RESUMEN

The data presented in this article are related to the research paper entitled "Observation of night-time emissions of the Earth in the near UV range from the International Space Station with the Mini-EUSO detector" (Remote Sensing of Environment, Volume 284, January 2023, 113336, https://doi.org/10.1016/j.rse.2022.113336). The data have been acquired with the Mini-EUSO detector, an UV telescope operating in the range 290-430 nm and located inside the International Space Station. The detector was launched in August 2019, and it has started operations from the nadir-facing UV-transparent window in the Russian Zvezda module in October 2019. The data presented here refer to 32 sessions acquired between 2019-11-19 and 2021-05-06. The instrument consists of a Fresnel-lens optical system and a focal surface composed of 36 multi-anode photomultiplier tubes, each with 64 channels, for a total of 2304 channels with single photon counting sensitivity. The telescope, with a square field-of-view of 44°, has a spatial resolution on the Earth surface of 6.3 km and saves triggered transient phenomena with a temporal resolution of 2.5 µs and 320 µs. The telescope also operates in continuous acquisition at a 40.96 ms scale. In this article, large-area night-time UV maps obtained processing the 40.96 ms data, taking averages over regions of some specific geographical areas (e.g., Europe, North America) and over the entire globe, are presented. Data are binned into 0.1° × 0.1° or 0.05° × 0.05° cells (depending on the scale of the map) over the Earth's surface. Raw data are made available in the form of tables (latitude, longitude, counts) and .kmz files (containing the .png images). These are - to the best of our knowledge - the highest sensitivity data in this wavelength range and can be of use to various disciplines.

3.
Space Sci Rev ; 218(1): 3, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35153338

RESUMEN

EUSO-Balloon is a pathfinder for JEM-EUSO, the mission concept of a spaceborne observatory which is designed to observe Ultra-High Energy Cosmic Ray (UHECR)-induced Extensive Air Showers (EAS) by detecting their UltraViolet (UV) light tracks "from above." On August 25, 2014, EUSO-Balloon was launched from Timmins Stratospheric Balloon Base (Ontario, Canada) by the balloon division of the French Space Agency CNES. After reaching a floating altitude of 38 km, EUSO-Balloon imaged the UV light in the wavelength range ∼290-500 nm for more than 5 hours using the key technologies of JEM-EUSO. The flight allowed a good understanding of the performance of the detector to be developed, giving insights into possible improvements to be applied to future missions. A detailed measurement of the photoelectron counts in different atmospheric and ground conditions was achieved. By means of the simulation of the instrument response and by assuming atmospheric models, the absolute intensity of diffuse light was estimated. The instrument detected hundreds of laser tracks with similar characteristics to EASs shot by a helicopter flying underneath. These are the first recorded laser tracks measured from a fluorescence detector looking down on the atmosphere. The reconstruction of the direction of the laser tracks was performed. In this work, a review of the main results obtained by EUSO-Balloon is presented as well as implications for future space-based observations of UHECRs.

4.
Science ; 189(4206): 852-6, 1975 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-17812518

RESUMEN

The basic concepts for direct and catalyzed photodissociation of water have been summarized. Water dissociation in closed-cycle processes based on endothermic photochemical reactions offers a potential solution to the solar energy conversion problem. Transition metal complexes, whose excited state chemistry is extremely rich (23, 24) although mostly unexplored, are, in principle, suitable "catalysts" for cycles of this type. The most interesting cycles are those involving metal hydrido complexes or binuclear complexes in which the two metal atoms are bound into a macrocyclic ligand. Systematic investigations of the photochemistry of transition metal complexes with the aim of designing suitable systems for solar energy conversion have long-range promise and merit further consideration.

5.
Acta Otorhinolaryngol Ital ; 38(3): 251-256, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29984791

RESUMEN

SUMMARY: The aim of the present study was to assess the feasibility and utility of 3D printing technology in surgical planning of a transcutaneous bone-conduction hearing device (Bonebridge®) (BB), focusing on the identification of the proper location and placement of the transducer. 3D printed (3DP) models of three human cadaveric temporal bones, previously submitted to CT scan, were created with the representation of a topographic bone thickness map and the sinus pathway on the outer surface. The 3DP model was used to detect the most suitable location for the BB. A 3DP transparent mask that faithfully reproduced the surface of both the temporal bone and the 3DP model was also developed to correctly transfer the designated BB area. The accuracy of the procedure was verified by CT scan: a radiological marker was used to evaluate the degree of correspondence of the transducer site between the 3DP model and the human temporal bone. The BB positioning was successfully performed on all human temporal bones, with no difficulties in finding the proper location of the transducer. A mean error of 0.13 mm was found when the transducer site of the 3DP model was compared to that of the human temporal bone. The employment of 3D printing technology in surgical planning of BB positioning showed feasible results. Further studies will be required to evaluate its clinical applicability.


Asunto(s)
Audífonos , Planificación de Atención al Paciente , Impresión Tridimensional , Prótesis e Implantes , Tomografía Computarizada por Rayos X , Conducción Ósea , Cadáver , Diseño de Equipo , Estudios de Factibilidad , Humanos , Periodo Preoperatorio , Cirugía Asistida por Computador
6.
Acta Otorhinolaryngol Ital ; 37(4): 328-335, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28872163

RESUMEN

Benign paroxysmal positional vertigo (BPPV) is the most common type of peripheral vertigo. BPPV often relapses after the first episode, with a recurrence rate between 15% and 50%. To date both the aetiopathogenetic processes that lead to otoconia detachment and the factors that make BPPV a relapsing disease are still unclear, but recent epidemiological studies have shown a possible association with cardiovascular risk factors. The aim of the present study (Sesto Senso Survey) was to evaluate in the Italian population through an observational survey, the main demographic and clinical characteristics of patients with BPPV (first episode or recurrent) with particular focus on the potential cardiovascular risk factors. The survey was conducted in 158 vestibology centres across Italy on 2,682 patients (mean age 59.3 ± 15.0 years; 39.1% males and 60.9% females) suffering from BPPV, from January 2013 to December 2014. The results showed a high prevalence of cardiovascular risk factors such as high blood pressure (55.8%), hypercholesterolaemia (38.6%) and diabetes (17.7%), as well as a family history of cardiovascular disease (49.4%). A high percentage of patients also had hearing loss (42.9%), tinnitus (41.2%), or both (26.8%). The presence of hypertension, dyslipidaemia and pre-existing cardiovascular comorbidities were significantly related to recurrent BPPV episodes (OR range between 1.84 and 2.31). In addition, the association with diabetes and thyroid/autoimmune disease (OR range between 1.73 and 1.89) was relevant. The survey results confirm the significant association between cardiovascular comorbidities and recurrent BPPV and identify them as a potential important risk factor for recurrence of BPPV in the Italian population, paving the way for the evaluation of new therapeutic strategies in the treatment of this disease.


Asunto(s)
Vértigo Posicional Paroxístico Benigno , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Vértigo Posicional Paroxístico Benigno/complicaciones , Vértigo Posicional Paroxístico Benigno/diagnóstico , Vértigo Posicional Paroxístico Benigno/epidemiología , Enfermedades Cardiovasculares/complicaciones , Femenino , Encuestas Epidemiológicas , Humanos , Italia/epidemiología , Masculino , Persona de Mediana Edad , Registros , Adulto Joven
7.
Neotrop Entomol ; 46(5): 537-545, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-28144910

RESUMEN

The species of the Drosophila fasciola subgroup Wasserman represent the dominant section of the Drosophila repleta group Wasserman in the American rainforests and have a broad geographical distribution in the New World. However, despite of its wide range, the D. fasciola subgroup is one of the most overlooked D. repleta subgroups. Here, we report a molecular phylogenetic analysis focused on the D. fasciola subgroup using two mitochondrial [cytochrome oxidase subunit I (COI), cytochrome oxidase subunit II (COII)] and two nuclear [elongation factor-1alpha F1 (EF-alphaF1) and transformer (tra)] genes. Overall, we found that this subgroup is a monophyletic taxon, subdivided into two main internal branches: named Fas1 and Fas2 clades. The diversification of these clades is estimated to have begun in the middle Miocene, around 12 Ma [95% high posterior density (HPD) 9.0-15 Ma], and might be associated with the colonization of South America by Central America populations after the closure of Isthmus of Panama due to the temporal congruence between these events. The terminal branches had their origins estimated to be in the Pliocene or the Plio-Pleistocene transition. For the later estimates, both the geomorphological influences and the climatic oscillations of the Pleistocene may have played a role in shaping the diversification of the D. fasciola group.


Asunto(s)
Drosophila/clasificación , Filogenia , Animales , Evolución Biológica , América Central , Proteínas de Drosophila , Complejo IV de Transporte de Electrones/genética , Genes de Insecto , Proteínas Nucleares/genética , Factor 1 de Elongación Peptídica/genética , América del Sur
8.
Acta Otorhinolaryngol Ital ; 36(6): 506-512, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28177334

RESUMEN

In recent years the increasing development of hearing devices has led to a critical analysis of the standard methods employed to evaluate hearing function. Being too far from reality, conventional investigation of hearing loss based on pure-tone threshold audiometry and on mono/disyllabic word lists, presented in quiet conditions, has been shown to be inadequate. A speech-in-noise test using a roving-level adaptive method employs target and competing signals varying in level in order to reproduce everyday life speaking conditions and explore a more complete sound range. Up to now, only few roving-level adaptive tests have been published in the literature. We conducted a rovinglevel adaptive test in healthy Italian adults to produce new normative data on a language of Latin origin.


Asunto(s)
Pruebas Auditivas , Lenguaje , Ruido , Percepción del Habla , Adulto , Femenino , Humanos , Italia , Masculino , Persona de Mediana Edad , Valores de Referencia , Adulto Joven
9.
J Atr Fibrillation ; 8(6): 1397, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27909502

RESUMEN

In this study we wanted to verify the diagnostic value of tilt table test (TTT) to predict the efficacy of cardiac pacing (PM) for preventing recurrences of neurally mediated reflex syncope (NMS) in patients with cardioinhibitory activity (CI) documented by implantable loop recorder (ILR). Among patients selected by ILR in the context of severe clinical presentation of NMS, we analysed those who underwent PM implantation. In this observational and retrospective study we wanted to verify the results of TTT in the groups of treated patients with and without recurrences. We analysed 24 patients treated using a PM (10 male and 14 female, mean age 70 years). During an average follow-up period of 35 months the recurrence of syncope occurred in 7 patients (29%). 17 patients (71%) had not recurrences. TTT was negative in 15 patients out of 17 without recurrences (88%). Among the 7 patients with recurrences TTT was positive in 4 patients (57%). In conclusion, in this selected group of patients, a positive response to TTT is more likely correlated with a higher frequency of recurrences of syncope, while a negative response seems to predict the success of the pacing therapy. Consequently, PM could be insufficient to prevent the recurrences in the group of patients with positive TTT.

10.
J Atr Fibrillation ; 9(2): 1398, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27909530

RESUMEN

Through a retrospective study concerning the experience of our center in patients affected by Neurally Mediated reflex Syncope (NMS) we wanted to verify not only the diagnostic yield of the Implantable Loop Recorder (ILR) but its possible placebo therapeutic effect. In the context of patients affected by a severe clinical presentation of NMS identified through a careful clinical evaluation, we selected those who followed a diagnostic iter using the ILR. We analysed 84 patients (39 male and 45 female, mean age 71 years), during the period 2009-2013. 34 patients (40.5%) had no recurrences after a mean follow-up (FU) of 35 months, among these 17 concluded a FU of 4 years. 50 patients (59.5%) had recurrences and a specific diagnosis after an average period of 7 months. We found an important number of patients who showed a disappearance of syncope during an observation period of 2-3 and 4 years. At first glance this results could be explained considering the possible placebo therapeutic effect of ILR.

11.
Acta Otorhinolaryngol Ital ; 36(5): 415-420, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27958602

RESUMEN

MYH9-related disease (MYH9-RD) is a rare genetic syndromic disorder characterised by congenital thrombocytopenia and is associated with the risk of developing progressive sensorineural hearing loss, nephropathy and presenile cataracts during childhood or adult life. All consecutive patients enrolled in the Italian Registry for MYH9-RD with severe to profound deafness were included in a retrospective study. The study population involved 147 Italian patients with MYH9-RD: hearing loss was identified in 52% of cases and only 4 patients (6%) presented severe to profound deafness at a mean age of 33 years. Deafness was associated with mild spontaneous bleeding in all patients and with kidney involvement in 3 cases. Cochlear implantation was carried out in 3 cases with benefit, and no major complications were observed. Diagnosis was performed about 28 years after the first clinical manifestation of MYH9-RD, which was never suspected by an otolaryngologist. The clinical and diagnostic aspects of 4 patients with severe to profound deafness are discussed with a focus on therapeutic implications.


Asunto(s)
Sordera/etiología , Pérdida Auditiva Sensorineural/complicaciones , Trombocitopenia/congénito , Adulto , Sordera/diagnóstico , Femenino , Humanos , Masculino , Estudios Retrospectivos , Índice de Severidad de la Enfermedad , Trombocitopenia/complicaciones
12.
Acta Otorhinolaryngol Ital ; 36(3): 215-9, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-27214833

RESUMEN

Vertigo and dizziness are common symptoms in the general population, with an estimated prevalence between 20% and 56%. The aim of our work was to assess the point prevalence of these symptoms in a population of 2672 subjects. Patients were asked to answer a questionnaire; in the first part they were asked about demographic data and previous vertigo and or dizziness. Mean age of the sample was 48.3 ± 15 years, and 46.7% were males. A total of 1077 (40.3%) subjects referred vertigo/dizziness during their lifetime, and the mean age of the first vertigo attack was 39.2 ± 15.4 years; in the second part they were asked about the characteristics of vertigo (age of first episode, rotational vertigo, relapsing episodes, positional exacerbation, presence of cochlear symptoms) and lifetime presence of moderate to severe headache and its clinical features (hemicranial, pulsatile, associated with phono and photophobia, worse on effort). An age and sex effect was demonstrated, with symptoms 4.4 times more elevated in females and 1.8 times in people over 50 years. In the total sample of 2672 responders, 13.7% referred a sensation of spinning, 26.3% relapsing episodes, 12.9% positional exacerbation and 4.8% cochlear symptoms; 34.8% referred headache during their lifetime. Subjects suffering from headache presented an increased rate of relapsing episodes, positional exacerbation, cochlear symptoms and a lower age of occurrence of the first vertigo/dizziness episode. In the discussion, our data are compared with those of previous studies, and we underline the relationship between vertigo/dizziness from one side and headache with migrainous features on the other.


Asunto(s)
Mareo/complicaciones , Mareo/epidemiología , Cefalea/complicaciones , Vértigo/complicaciones , Vértigo/epidemiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Estudios Prospectivos , Autoinforme , Adulto Joven
13.
Clin Pharmacokinet ; 1(5): 373-84, 1976.
Artículo en Inglés | MEDLINE | ID: mdl-1017154

RESUMEN

Propranolol blood and plasma levels were measured after a single oral dose of 40 mg in patients with chronic renal failure, in patients undergoing regular dialysis treatment, and in healthy volunteers. Peak levels were observed in all cases within 1.5 to 3 hours. However, peak blood and plasma concentrations of propranolol in the chronic renal failure group were 2- to 3-fold higher (161 +/- 41 ng/ml) than those observed in the dialysis patients (47 +/- 9 ng/ml) and in the healthy volunteers (26 +/- 1 ng/ml). The apparent plasma clearance was also significantly reduced in the patients with chronic renal failure. The data suggest a reduced hepatic extraction in chronic renal failure patients. A significant increase in the fraction of the dose available to the systemic circulation was also found, together with a modification of apparent plasma half-life and volume of distribution in regular dialysis patients during the dialysis day as compared with the after-dialysis day. No extraction of propranolol by the dialyzer was noticed. Marked fluctuations in propranolol blood concentrations were also observed in patients on regular dialysis following continuous propranolol treatment. The suppressive effect of propranolol on plasma renin activity did not fully correlate with the hypotensive effect of the drug. On the basis of the reported data, propranolol should be used with great caution and at low doses in chronic renal failure.


Asunto(s)
Propranolol/sangre , Diálisis Renal , Uremia/sangre , Adulto , Femenino , Humanos , Cinética , Masculino , Persona de Mediana Edad , Propranolol/administración & dosificación , Propranolol/farmacología , Renina/sangre , Factores de Tiempo , Uremia/fisiopatología , Uremia/terapia
14.
Clin Neurophysiol ; 111(8): 1337-9, 2000 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10904212

RESUMEN

OBJECTIVE: Periodic alternating nystagmus has been associated with the instability of the velocity storage mechanism, which is known to play an important role in both the vestibulo-oculomotor and the optokinetic systems. In the present study we looked for a possible spinal equivalent to PAN. METHODS AND RESULTS: In 3 PAN patients, the H-reflex amplitude proved to be slightly but significantly influenced by nystagmus direction, in that it was greater when the nystagmus was beating toward the stimulation side. CONCLUSIONS: This finding suggests that projections from velocity storage may play a role not only in the ocular motor but also in assisting postural stability through the vestibulo-spinal system.


Asunto(s)
Nistagmo Patológico/fisiopatología , Médula Espinal/fisiopatología , Vestíbulo del Laberinto/fisiopatología , Adolescente , Anciano , Análisis de Varianza , Estimulación Eléctrica , Femenino , Reflejo H/fisiología , Humanos , Masculino , Persona de Mediana Edad
15.
J Am Soc Echocardiogr ; 9(3): 241-50, 1996.
Artículo en Inglés | MEDLINE | ID: mdl-8736006

RESUMEN

Pulmonary venous flow velocity recordings have been found to be useful in complementing the information obtained from the mitral flow velocity and improving the assessment of left ventricular diastolic pressures. This study was undertaken to evaluate the accuracy of mitral flow and pulmonary venous flow variables, recorded by transthoracic Doppler echocardiography, in estimating left ventricular end-diastolic pressure (LVEDP) in 101 consecutive patients with coronary artery disease undergoing diagnostic left-sided heart catheterization. Patients were assigned to three groups according to the values of LVEDP (group 1, < or = 12 mm Hg; group 2, between 13 and 19 mm Hg; and group 3, > or = 20 mm Hg). LVEDP correlated most strongly with systolic fraction of pulmonary venous flow (r = -0.76), isovolumic relaxation time (r = -0.76), E/A ratio (r = 0.74), deceleration time of early mitral flow (r = -0.74), and mitral A wave duration/pulmonary venous A wave duration (AD/PVAD) ratio (r = -0.70) (p < 0.01 for each correlation). Discriminant analysis demonstrated that deceleration time, AD/PVAD ratio, and isovolumic relaxation time were major determinants of LVEDP, with 87.1% of patients correctly assigned to study groups; 97% of patients of group 1 and 95% of patients of group 3 were identified, whereas the accuracy in identifying the patients of group 2 was lower (41%). Deceleration times of 140 msec or less and AD/PVAD ratios of 0.9 or less were the best cutoff points in predicting an LVEDP of 20 mm Hg or greater. Multiple linear regression analysis demonstrated that the combination of mitral flow and pulmonary venous flow velocity variables provided a better estimation of LVEDP compared with that obtained from mitral flow velocity recordings alone (r = 0.88 versus 0.79; F test, 20.6). We conclude that combined analysis of mitral flow and pulmonary venous flow velocity provides, in patients with coronary artery disease, a noninvasive estimation of LVEDP with an accurate prediction of pressures of 12 mm Hg or less and 20 mm Hg or greater and less accurate prediction of intermediate values.


Asunto(s)
Presión Sanguínea/fisiología , Enfermedad Coronaria/diagnóstico por imagen , Ecocardiografía Doppler de Pulso , Volumen Sistólico/fisiología , Función Ventricular Izquierda/fisiología , Adulto , Anciano , Anciano de 80 o más Años , Velocidad del Flujo Sanguíneo/fisiología , Cateterismo Cardíaco , Enfermedad Coronaria/fisiopatología , Diástole/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Válvula Mitral/diagnóstico por imagen , Válvula Mitral/fisiopatología , Contracción Miocárdica/fisiología , Venas Pulmonares/diagnóstico por imagen , Venas Pulmonares/fisiopatología , Valores de Referencia
16.
Acta Otolaryngol ; 115(1): 34-9, 1995 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-7762382

RESUMEN

The effects of hypotonic and hypertonic solutions (the normal value was 240 mOsm) on posterior canal resting and evoked discharge were studied in isolated labyrinth preparations. Hypotonic solutions (60-180 mOsm) were obtained by reducing the perilymphatic NaCl content. Hypertonic solutions (300-420 mOsm) were obtained by adding to normal perilymphatic solutions suitable amounts of NaCl, glucose, sucrose, glycerol, mannitol and urea. The results demonstrated that any kind of receptor activity was inhibited by hypotonic solutions. On the contrary, hypertonic solutions produced different effects on resting and evoked activity. The resting discharge was, with the exception of urea, constantly increased whereas the evoked responses were constantly decreased by all the hypertonic solutions tested. The possible effects of media with changed osmolarity in Meniere's patients is also discussed.


Asunto(s)
Conducción Nerviosa/efectos de los fármacos , Concentración Osmolar , Ranidae , Vestíbulo del Laberinto/efectos de los fármacos , Animales , Técnicas de Cultivo , Hidropesía Endolinfática/metabolismo , Soluciones Hipertónicas/farmacocinética , Soluciones Hipertónicas/farmacología , Soluciones Hipotónicas/farmacocinética , Soluciones Hipotónicas/farmacología , Perilinfa/efectos de los fármacos
17.
Acta Otolaryngol ; 111(5): 820-6, 1991.
Artículo en Inglés | MEDLINE | ID: mdl-1759566

RESUMEN

The effects of endolymphatic and perilymphatic pressure changes on resting and mechanically evoked responses were studied in isolated posterior semicircular canals of the frog. The results demonstrated that ampullar receptors are extremely sensitive to hydrostatic pressure changes (0.25 mm H2O were sufficient to produce distinct changes), being inhibited by endolymphatic pressure increases and facilitated by perilymphatic ones. Intracellular recordings from single afferent axons showed that the effects of hydrostatic pressure result from a modified transmitter release from the synaptic pole of the hair cells. Unlike resting activity, mechanically evoked activity was always depressed in the presence of a hydrostatic pressure. This indicates that the sensitivity of ampullar receptors to mechanical stimuli, i.e. the gain of the conversion process, is maximal when no pressure is present between the inner and the outer fluid. The possible action of hydrostatic pressure on vestibular receptors is discussed.


Asunto(s)
Canales Semicirculares/fisiología , Nervio Vestibular/fisiología , Vías Aferentes/fisiología , Animales , Axones/fisiología , Endolinfa/fisiología , Potenciales Evocados Auditivos , Presión Hidrostática , Rana esculenta
18.
Neotrop Entomol ; 42(4): 384-92, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23949858

RESUMEN

In this work, we investigated the morphological variation of the intromittent male copulatory organ (aedeagus) of specimens from natural populations of two cactophilic Drosophila species distributed in the southeast region of Brazil, Drosophila gouveai Tidon-Sklorz & Sene and Drosophila antonietae Tidon-Sklorz & Sene. It was explored how the within-species variability is arranged for both species, considering their historical and ecological features. Our results showed two distinct aedeagal morphologies for these species, and differences within species were observed only in D. gouveai as specimens could be distinguished by their population origin. In contrast, after size discrepancies correction, this feature was not detected in D. antonietae. The contrasting patterns of intraspecific variation, together with the other features exhibited by these two species, are most likely to be explained by differences in the historical host plant association and distribution and in demographic events, which determined the evolutionary history of these two South American cactophilic Drosophila species.


Asunto(s)
Drosophila/anatomía & histología , Drosophila/clasificación , Animales , Brasil
20.
Environ Entomol ; 39(3): 865-73, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20550800

RESUMEN

Cactophilic Drosophila flies are excellent models to study adaptation to a relatively narrow spectrum of potential host plants and host-driven evolutionary diversification. Previous studies suggested a complex genetic architecture of wing and male genital morphology in phylogenetically basal species of the D. buzzatii cluster. In this work, we investigate the effect of experimental hybridization and host plant shifts on male genital and wing morphology in D. gouveai Tidon-Sklorz and Sene and D. antonietae Tidon-Sklorz and Sene, a pair of more recently derived species. We explicitly tested the hypotheses that wing and male genital morphology in interspecific hybrids depend on the host plant in which flies were grown. Our study shows that cactus hosts exert a strong effect on genital and wing morphology and that hybrids can be clearly differentiated on the basis of wing and genital morphology from both parental species. However, the extent of morphological differentiation between hybrids and pure species as well as plasticity patterns varied across organs, suggesting a complex genetic architecture for the studied traits.


Asunto(s)
Cactaceae , Drosophila/anatomía & histología , Genitales Masculinos/anatomía & histología , Hibridación Genética , Alas de Animales/anatomía & histología , Adaptación Biológica , Animales , Drosophila/genética , Drosophila/crecimiento & desarrollo , Femenino , Genitales Masculinos/crecimiento & desarrollo , Masculino , Especificidad de la Especie , Alas de Animales/crecimiento & desarrollo
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