The Conditional Distribution of Excess Returns: An Empirical Analysis

econometrics ; evaluation

Indications for flexible fiberoptic bronchoscopy and its safety in the very elderly

Aim. To evaluate the indications and the safety of fiberoptic bronchoscopy (FOB) with bronchoalveolar lavage (BAL), protected specimen brushing (PSB), endobronchial biopsy (EBB), and transbronchial biopsy (TBB) in a population of very elderly patients. Methods. We performed a retrospective study of all adult patients, aged 50 years or older, who underwent FOB in the Bronchology Unit of the University of Parma Hospital between 1 January, 2003 and 31 April, 2005. Bronchoscopy records of 436 consecutive patients, including 191 patients, 75 yrs of age and older ("very elderly"; =>75 yrs), were reviewed. Results. Patients aged 75 years were no different with regard to gender, BMI, baseline FEV1/FVC ratio, baseline SaO2, and blood pressure. The primary indication in patients aged <75 years, was to assist in the diagnosis of a pulmonary mass of unknown aetiology (33%) and to remove secretions in the very elderly patients (31%). Indications for FOB and sampling procedures in the two groups were similar. Approximately 30% of patients in each group required supplemental oxygen during the procedure and fever occurred in 9.2% and 10.3% of patients, respectively.Hypertension and bleeding were relatively rare and did not occur more often in the very elderly. Conclusions. Indication for FOB did not vary with age and adverse events in both groups were uncommon and generally not severe

Nanobeam photonic crystal cavity quantum dot laser

The lasing behavior of one dimensional GaAs nanobeam cavities with embedded InAs quantum dots is studied at room temperature. Lasing is observed throughout the quantum dot PL spectrum, and the wavelength dependence of the threshold is calculated. We study the cavity lasers under both 780 nm and 980 nm pump, finding thresholds as low as 0.3 uW and 19 uW for the two pump wavelengths, respectively. Finally, the nanobeam cavity laser wavelengths are tuned by up to 7 nm by employing a fiber taper in near proximity to the cavities. The fiber taper is used both to efficiently pump the cavity and collect the cavity emission.Comment: 8 pages; 6 figure

Modelling of photonic wire Bragg Gratings

Some important properties of photonic wire Bragg grating structures have been investigate. The design, obtained as a generalisation of the full-width gap grating, has been modelled using 3D finite-difference time-domain simulations. Different types of stop-band have been observed. The impact of the grating geometry on the lowest order (longest wavelength) stop-band has been investigated - and has identified deeply indented configurations where reduction of the stop-bandwidth and of the reflectivity occurred. Our computational results have been substantially validated by an experimental demonstration of the fundamental stop-band of photonic wire Bragg gratings fabricated on silicon-on-insulator material. The accuracy of two distinct 2D computational models based on the effective index method has also been studied - because of their inherently much greater rapidity and consequent utility for approximate initial designs. A 2D plan-view model has been found to reproduce a large part of the essential features of the spectral response of full 3D models

Toward an Astrochronology-Based Age-Model for a Messinian Pre-Evaporitic Succession: The Example of Torrente Vaccarizzo Section in Sicily (Italy)

Tectonic, paleoenvironmental, and paleoclimatic unstable conditions preceding the onset of the Messinian Salinity Crisis (MSC) highly affected marine life. Changes in calcareous plankton association are overall registered in the Mediterranean. They consist of a general transition from abundant and well-diversified planktonic associations to strictly oligotypic assemblages that precede their total disappearance at the onset of evaporitic precipitation. In this work, an accurate quantitative analysis of calcareous plankton, both foraminifers and nannofossils, has been carried out in the Torrente Vaccarizzo Section of Sicily (southern Italy). The aim is to independently define a chronostratigraphic pattern of bioevents preceding the MSC in the absence of magnetostratigraphic or radiometric constraints. The fluctuating abundance of the genus Orbulina fits well with the 100 ky Eccentricity maxima, and it is successfully applied to build an astronomically calibrated age-model for the section. On this basis, all the biohorizons have been recalibrated and discussed with regard to the previous literature. Abundant influxes of selected species demonstrated to be of local significance since they are highly affected by paleoenvironmental and paleoclimatic conditions. A chronological sequence of foraminifer and nannofossil events marks the onset of the MSC with a derived age of 5.957 My, which agrees well with previous findings from other Mediterranean sections. This methodology and the new biostratigraphic events may be useful for future studies on pre-evaporitic successions of the Mediterranean

Extracellular ATP-induced NO production and its dependence on membrane Ca2+ flux in Salvia miltiorrhiza hairy roots

Extracellular ATP (eATP) is a novel signalling agent, and nitric oxide (NO) is a well-established signal molecule with diverse functions in plant growth and development. This study characterizes NO production induced by exogenous ATP and examines its relationship with other important signalling agents, Ca2+ and H2O2 in Salvia miltiorrhiza hairy root culture. Exogenous ATP was applied at 10–500 μM to the hairy root cultures and stimulated NO production was detectable within 30 min. The NO level increased with ATP dose from 10–100 μM but decreased from 100–200 μM or higher. The ATP-induced NO production was mimicked by a non-hydrolysable ATP analogue ATPγS, but only weakly by ADP, AMP or adenosine. The ATP-induced NO production was blocked by Ca2+ antagonists, but not affected by a protein kinase inhibitor. ATP also induced H2O2 production, which was dependent on both Ca2+ and protein kinases, and also on NO biosynthesis. On the other hand, ATP induced a rapid increase in the intracellular Ca2+ level, which was dependent on NO but not H2O2. The results suggest that NO is implicated in ATP-induced responses and signal transduction in plant cells, and ATP signalling is closely related to Ca2+ and ROS signalling

Broadband Reconfiguration of OptoMechanical Filters

We demonstrate broad-band reconfiguration of coupled photonic crystal nanobeam cavities by using optical gradient force induced mechanical actuation. Propagating waveguide modes that exist over wide wavelength range are used to actuate the structures and in that way control the resonance of localized cavity mode. Using this all-optical approach, more than 18 linewidths of tuning range is demonstrated. Using on-chip temperature self-referencing method that we developed, we determined that 20 % of the total tuning was due to optomechanical reconfiguration and the rest due to thermo-optic effects. Independent control of mechanical and optical resonances of our structures, by means of optical stiffening, is also demonstrated

Chronic productive cough in young adults is very often due to chronic rhino-sinusitis

Background. Chronic productive cough is a common clinical problem; often potential causes outside the lower respiratory tract are forgotten or ignored. The aim of this study was to make a precise etiopathogenetic diagnosis of chronic productive cough in young adults. Methods. In a clinical setting, 212 subjects (mean age 41±5 years) who had reported chronic productive cough in a previous postal survey of a young adult population underwent within two years clinical and functional investigations following a rational diagnostic approach. Two pulmonologists independently established the diagnosis using a clinically structured interview on nasal and respiratory symptoms, spirometry and other tests when appropriate (bronchodilator test or methacholine bronchial challenge, chest radiography); if rhino-sinusitis was suspected, subjects underwent an ENT examination with nasal endoscopy and/or sinus computed tomography. Results. At the end of the diagnostic procedure, 87 subjects (41%) no longer had chronic productive cough and had normal function. Fifty-eight subjects (27%) had chronic rhino-sinusitis; seventeen subjects (8%) had asthma, and of these fourteen also had chronic rhino-sinusitis; 50 subjects (24%) had COPD stage 0+, of these seven also had chronic rhino-sinusitis. Chronic rhino-sinusitis was more frequent in females than in males (p<0.05). Conclusions. Both in clinical practice and in epidemiological studies, it is important to consider that the origin of chronic productive cough could be frequently outside the lower respiratory tract; a consistent percentage of young adults with persistent productive cough has indeed chronic rhino-sinusitis

Effects of controlled diesel exhaust exposure on apoptosis and proliferation markers in bronchial epithelium – an in vivo bronchoscopy study on asthmatics, rhinitics and healthy subjects

BackgroundEpidemiological evidence demonstrates that exposure to traffic-derived pollution worsens respiratory symptoms in asthmatics, but controlled human exposure studies have failed to provide a mechanism for this effect. Here we investigated whether diesel exhaust (DE) would induce apoptosis or proliferation in the bronchial epithelium in vivo and thus contribute to respiratory symptoms.MethodsModerate (n?=?16) and mild (n?=?16) asthmatics, atopic non-asthmatic controls (rhinitics) (n?=?13) and healthy controls (n?=?21) were exposed to filtered air or DE (100 ?g/m 3 ) for 2 h, on two separate occasions. Bronchial biopsies were taken 18 h post-exposure and immunohistochemically analysed for pro-apoptotic and anti-apoptotic proteins (Bad, Bak, p85 PARP, Fas, Bcl-2) and a marker of proliferation (Ki67). Positive staining was assessed within the epithelium using computerized image analysis.ResultsNo evidence of epithelial apoptosis or proliferation was observed in healthy, allergic or asthmatic airways following DE challenge.ConclusionIn the present study, we investigated whether DE exposure would affect markers of proliferation and apoptosis in the bronchial epithelium of asthmatics, rhinitics and healthy controls, providing a mechanistic basis for the reported increased airway sensitivity in asthmatics to air pollutants. In this first in vivo exposure investigation, we found no evidence of diesel exhaust-induced effects on these processes in the subject groups investigated