Aerodynamic Design of Integrated Propulsion-Airframe Configuration of the Hybrid Wing-Body Aircraft

Hybrid Wing Body (HWB) aircraft is characterized by a flattened and airfoil-shaped body, which produces a substantial portion of the total lift. The body form is composed of distinct and separate wing structures, though the wings are smoothly blended into the body. This concept has been studied widely and results suggest remarkable performance improvements over the conventional tube and wing transport1,2. HWB incorporates design features from both a futuristic fuselage and flying wing design, which houses most of the crew, payload and equipment inside the main centerbody structure

Diurnal Variation in Martian Dust Devil Activity

We show that the dust devil parameterisation in use in most Mars Global Circulation Models (MGCMs) results in an unexpectedly high level of dust devil activity during morning hours. Prior expectations of the diurnal variation of Martian dust devils are based mainly upon the observed behaviour of terrestrial dust devils: i.e. that the majority occur during the afternoon. We instead find that large areas of the Martian surface experience dust devil activity during the morning in our MGCM, and that many locations experience a peak in dust devil activity before mid-sol. We find that the diurnal variation in dust devil activity is governed by near-surface wind speeds. Within the range of daylight hours, higher wind speeds tend to produce higher levels of dust devil activity, rather than the activity simply being governed by the availability of heat at the planet's surface, which peaks in early afternoon. Evidence for whether the phenomenon we observe is real or an artefact of the parameterisation is inconclusive. We compare our results with surface-based observations of Martian dust devil timings and obtain a good match with the majority of surveys. We do not find a good match with orbital observations, which identify a diurnal distribution more closely matching that of terrestrial dust devils, but orbital observations have limited temporal coverage, biased towards the early afternoon. We propose that the generally accepted description of dust devil behaviour on Mars is incomplete, and that theories of dust devil formation may need to be modified specifically for the Martian environment. Further surveys of dust devil observations are required to support any such modifications. These surveys should include both surface and orbital observations, and the range of observations must encompass the full diurnal period and consider the wider meteorological context surrounding the observations

Orbital Observations of Dust Lofted by Daytime Convective Turbulence

Over the past several decades, orbital observations of lofted dust have revealed the importance of mineral aerosols as a climate forcing mechanism on both Earth and Mars. Increasingly detailed and diverse data sets have provided an ever-improving understanding of dust sources, transport pathways, and sinks on both planets, but the role of dust in modulating atmospheric processes is complex and not always well understood. We present a review of orbital observations of entrained dust on Earth and Mars, particularly that produced by the dust-laden structures produced by daytime convective turbulence called “dust devils”. On Earth, dust devils are thought to contribute only a small fraction of the atmospheric dust budget; accordingly, there are not yet any published accounts of their occurrence from orbit. In contrast, dust devils on Mars are thought to account for several tens of percent of the planet’s atmospheric dust budget; the literature regarding martian dust devils is quite rich. Because terrestrial dust devils may temporarily contribute significantly to local dust loading and lowered air quality, we suggest that martian dust devil studies may inform future studies of convectively-lofted dust on Earth

Development and evaluation of a calibrator material for nucleic acid-based assays for diagnosing aspergillosis.

Contains fulltext : 185003.pdf (publisher's version ) (Closed access)Twelve laboratories evaluated candidate material for an Aspergillus DNA calibrator. The DNA material was quantified using limiting-dilution analysis; the mean concentration was determined to be 1.73 x 10(10) units/ml. The calibrator can be used to standardize aspergillosis diagnostic assays which detect and/or quantify nucleic acid.1 juli 201

A nonparametric feature for neonatal EEG seizure detection based on a representation of pseudo-periodicity

The NFM is a new method of signal representation that can be used to detecting pseudo-periodicity in the neonatal EEG, using data-driven TF path integration to compress a TFD into a representation of nonstationary signal component power and mean frequency. (Additional details can be found in the comprehensive book on Time-Frequency Signal Analysis and Processing (see http://www.elsevier.com/locate/isbn/0080443354). In addition, the most recent upgrade of the original software package that calculates Time-Frequency Distributions and Instantaneous Frequency estimators can be downloaded from the web site: www.time-frequency.net. This was the first software developed in the field, and it was first released publicly in 1987 at the 1st ISSPA conference held in Brisbane, Australia, and then continuously updated).Automated methods of neonatal EEG seizure detection attempt to highlight the evolving, stereotypical, pseudo-periodic, nature of EEG seizure while rejecting the nonstationary, modulated, coloured stochastic background in the presence of various EEG artefacts. An important aspect of neonatal seizure detection is, therefore, the accurate representation and detection of pseudo-periodicity in the neonatal EEG. This paper describes a method of detecting pseudo-periodic components associated with neonatal EEG seizure based on a novel signal representation; the nonstationary frequency marginal (NFM). The NFM can be considered as an alternative time-frequency distribution (TFD) frequency marginal. This method integrates the TFD along data-dependent, time-frequency paths that are automatically extracted from the TFD using an edge linking procedure and has the advantage of reducing the dimension of a TFD. The reduction in dimension simplifies the process of estimating a decision statistic designed for the detection of the pseudo-periodicity associated with neonatal EEG seizure. The use of the NFM resulted in a significant detection improvement compared to existing stationary and nonstationary methods. The decision statistic estimated using the NFM was then combined with a measurement of EEG amplitude and nominal pre- and post-processing stages to form a seizure detection algorithm. This algorithm was tested on a neonatal EEG database of 18 neonates, 826 h in length with 1389 seizures, and achieved comparable performance to existing second generation algorithms (a median receiver operating characteristic area of 0.902; IQR 0.835–0.943 across 18 neonates)

Determination of Cryptosporidium Parvum Oocyst viability by fluorescence in situ hybridization (FISH) using a ribosomal RNA-directed probes

Free to read from publisher website AIMS: Fluorescence in situ hybridization (FISH) has been proposed for species-specific detection, and viability determination of Cryptosporidium parvum oocysts. FISH-based viability determination depends on rRNA decay after loss of viability. We examined the effects of RNase(s) and RNase inhibitors on FISH of C. parvum. METHODS AND RESULTS: FISH was performed using a 5'-Texas red-labelled DNA oligonucleotide probe at 1 pM microl(-1). Intact and heat-permeabilized oocysts were treated with 1-100 microg ml(-1) RNase. FISH of intact oocysts appeared unaffected by exogenous RNase if this was neutralized before permeabilization. FISH fluorescence of heat-killed oocysts stored in phosphate-buffered saline at room temperature decayed by 1/2 after 55 h, but remained detectable after 6 days. Addition of vanadyl ribonucleoside complex (VRC) extended rRNA half-life of heat-permeabilized oocysts to 155 h. CONCLUSIONS: Extended rRNA half-life may result in viability overestimation using FISH. RNase pretreatment before FISH is recommended to destroy residual rRNA in recently killed oocysts. Incorporation of 1-10 mM l(-1) VRC before FISH permeabilization steps should neutralize RNase activity. SIGNIFICANCE AND IMPACT OF THE STUDY: Elimination of FISH fluorescence of nonviable C. parvum is desirable. Use of RNase and VRC is suggested to reduce numbers of false-positive 'viable' oocysts