121 research outputs found
A model-based approach to adjust microwave observations for operational applications: results of a campaign at Munich Airport in winter 2011/2012
In the frame of the project "LuFo iPort VIS" which focuses on the implementation of a site-specific visibility forecast, a field campaign was organised to offer detailed information to a numerical fog model. As part of additional observing activities, a 22-channel microwave radiometer profiler (MWRP) was operating at the Munich Airport site in Germany from October 2011 to February 2012 in order to provide vertical temperature and humidity profiles as well as cloud liquid water information. Independently from the model-related aims of the campaign, the MWRP observations were used to study their capabilities to work in operational meteorological networks. Over the past decade a growing quantity of MWRP has been introduced and a user community (MWRnet) was established to encourage activities directed at the set up of an operational network. On that account, the comparability of observations from different network sites plays a fundamental role for any applications in climatology and numerical weather forecast. <br><br> In practice, however, systematic temperature and humidity differences (bias) between MWRP retrievals and co-located radiosonde profiles were observed and reported by several authors. This bias can be caused by instrumental offsets and by the absorption model used in the retrieval algorithms as well as by applying a non-representative training data set. At the Lindenberg observatory, besides a neural network provided by the manufacturer, a measurement-based regression method was developed to reduce the bias. These regression operators are calculated on the basis of coincident radiosonde observations and MWRP brightness temperature (TB) measurements. However, MWRP applications in a network require comparable results at just any site, even if no radiosondes are available. <br><br> The motivation of this work is directed to a verification of the suitability of the operational local forecast model COSMO-EU of the Deutscher Wetterdienst (DWD) for the calculation of model-based regression operators in order to provide unbiased vertical profiles during the campaign at Munich Airport. The results of this algorithm and the retrievals of a neural network, specially developed for the site, are compared with radiosondes from Oberschleißheim located about 10 km apart from the MWRP site. Outstanding deviations for the lowest levels between 50 and 100 m are discussed. Analogously to the airport experiment, a model-based regression operator was calculated for Lindenberg and compared with both radiosondes and operational results of observation-based methods. <br><br> The bias of the retrievals could be considerably reduced and the accuracy, which has been assessed for the airport site, is quite similar to those of the operational radiometer site at Lindenberg above 1 km height. Additional investigations are made to determine the length of the training period necessary for generating best estimates. Thereby three months have proven to be adequate. The results of the study show that on the basis of numerical weather prediction (NWP) model data, available everywhere at any time, the model-based regression method is capable of providing comparable results at a multitude of sites. Furthermore, the approach offers auspicious conditions for automation and continuous updating
Forecast indices from a ground-based microwave radiometer for operational meteorology
Abstract. Today, commercial microwave radiometer profilers (MWRPs) are robust and unattended instruments providing real-time, accurate atmospheric observations at ~ 1 min temporal resolution under nearly all weather conditions. Common commercial units operate in the 20–60 GHz frequency range and are able to retrieve profiles of temperature, vapour density, and relative humidity. Temperature and humidity profiles retrieved from MWRP data are used here to feed tools developed for processing radiosonde observations to obtain values of forecast indices (FIs) commonly used in operational meteorology. The FIs considered here include K index, total totals, KO index, Showalter index, T1 gust, fog threat, lifted index, S index (STT), Jefferson index, microburst day potential index (MDPI), Thompson index, TQ index, and CAPE (convective available potential energy). Values of FIs computed from radiosonde and MWRP-retrieved temperature and humidity profiles are compared in order to quantitatively demonstrate the level of agreement and the value of continuous FI updates. This analysis is repeated for two sites at midlatitude, the first one located at low altitude in central Europe (Lindenberg, Germany) and the second one located at high altitude in North America (Whistler, Canada). It is demonstrated that FIs computed from MWRPs well correlate with those computed from radiosondes, with the additional advantage of nearly continuous updates. The accuracy of MWRP-derived FIs is tested against radiosondes, taken as a reference, showing different performances depending upon index and environmental situation. Overall, FIs computed from MWRP retrievals agree well with radiosonde values, with correlation coefficients usually above 0.8 (with few exceptions). We conclude that MWRP retrievals can be used to produce meaningful FIs, with the advantage (with respect to radiosondes) of nearly continuous updates
Forecast indices from a ground-based microwave radiometer for operational meteorology
Today, commercial microwave radiometer profilers (MWRPs) are robust and
unattended instruments providing real-time, accurate atmospheric observations
at ~ 1 min temporal resolution under nearly all weather
conditions. Common commercial units operate in the 20–60 GHz frequency range
and are able to retrieve profiles of temperature, vapour density, and
relative humidity. Temperature and humidity profiles retrieved from MWRP
data are used here to feed tools developed for processing radiosonde
observations to obtain values of forecast indices (FIs) commonly used in
operational meteorology. The FIs considered here include K index, total
totals, KO index, Showalter index, T1 gust, fog threat, lifted index, S index (STT), Jefferson index, microburst day potential index (MDPI), Thompson index, TQ index, and CAPE (convective available potential energy).
Values of FIs computed from radiosonde and MWRP-retrieved temperature and
humidity profiles are compared in order to quantitatively demonstrate the
level of agreement and the value of continuous FI updates. This analysis is
repeated for two sites at midlatitude, the first one located at low altitude
in central Europe (Lindenberg, Germany) and the second one located at
high altitude in North America (Whistler, Canada). It is demonstrated that
FIs computed from MWRPs well correlate with those computed from radiosondes,
with the additional advantage of nearly continuous updates. The accuracy of
MWRP-derived FIs is tested against radiosondes, taken as a reference, showing
different performances depending upon index and environmental situation.
Overall, FIs computed from MWRP retrievals agree well with radiosonde values,
with correlation coefficients usually above 0.8 (with few exceptions). We
conclude that MWRP retrievals can be used to produce meaningful FIs, with the
advantage (with respect to radiosondes) of nearly continuous updates
Possibilità di differenziazione degli elettrodi cocleari nelle misurazioni radiologiche della posizione intracocleare e dell'angolo cordo-facciale
Con l'incremento del numero di impianti cocleari effettuati, il controllo di qualità è divenuto sempre più importante. Oltre alle misurazioni biofisiche intraoperatorie ci si può avvalere dell'imaging radiologico. Una nuova tecnica utilizzata in questo campo è il Cone Beam CT (CBCT). Nel presente studio sono stati valutati 65 casi (35 Nucleus Contour AdvanceCochlear; 30 Flex SoftMedEl) studiati mediante CBCT (Accu-I-tomo F17, Morita, Kyoto, Japan). Nello specifico sono stati rilevati: l'angolo di inserzione, l'altezza dell'impianto, la distanza dell'elettrodo dalla parete mediale o laterale, l'angolo tra la corda del timpano e il nervo facciale e la posizione precisa del filo dell'elettrodo nell'angolo cordo-facciale. È stato inoltre possibile valutare la differenza tra il decorso peri-modiolare e laterale degli elettrodi. I dati presentati dimostrano l'accuratezza e il vantaggio della CBCT nella visualizzazione di piccole strutture grazie al ridotto numero di artefatti da indurimento del fascio. Inoltre nel 75% dei pazienti è stato possibile visualizzare l'angolo tra la corda del timpano e il nervo facciale. È stato possibile notare differenze significative fra i vari tipi di elettrodo in funzione del tipo di rapporto con il nervo facciale. In conclusione mediante la CBCT è possibile ottenere una visualizzazione precisa e dettagliate misurazioni della posizione intracocleare dei diversi elettrodi. È persino possibile la corretta valutazione della posizione dell'elettrodo rispetto all'angolo cordo- facciale. La CBCT è quindi, dal nostro punto di vista, un utile strumento per il controllo intra e post-operatorio degli impianti cocleari
Diagnosing selective mutism: a critical review of measures for clinical practice and research
Education and Child Studie
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Protective intraoperative ventilation with higher versus lower levels of positive end-expiratory pressure in obese patients (PROBESE): study protocol for a randomized controlled trial
Background: Postoperative pulmonary complications (PPCs) increase the morbidity and mortality of surgery in obese patients. High levels of positive end-expiratory pressure (PEEP) with lung recruitment maneuvers may improve intraoperative respiratory function, but they can also compromise hemodynamics, and the effects on PPCs are uncertain. We hypothesized that intraoperative mechanical ventilation using high PEEP with periodic recruitment maneuvers, as compared with low PEEP without recruitment maneuvers, prevents PPCs in obese patients. Methods/design The PRotective Ventilation with Higher versus Lower PEEP during General Anesthesia for Surgery in OBESE Patients (PROBESE) study is a multicenter, two-arm, international randomized controlled trial. In total, 2013 obese patients with body mass index ≥35 kg/m2 scheduled for at least 2 h of surgery under general anesthesia and at intermediate to high risk for PPCs will be included. Patients are ventilated intraoperatively with a low tidal volume of 7 ml/kg (predicted body weight) and randomly assigned to PEEP of 12 cmH2O with lung recruitment maneuvers (high PEEP) or PEEP of 4 cmH2O without recruitment maneuvers (low PEEP). The occurrence of PPCs will be recorded as collapsed composite of single adverse pulmonary events and represents the primary endpoint. Discussion To our knowledge, the PROBESE trial is the first multicenter, international randomized controlled trial to compare the effects of two different levels of intraoperative PEEP during protective low tidal volume ventilation on PPCs in obese patients. The results of the PROBESE trial will support anesthesiologists in their decision to choose a certain PEEP level during general anesthesia for surgery in obese patients in an attempt to prevent PPCs. Trial registration ClinicalTrials.gov identifier: NCT02148692. Registered on 23 May 2014; last updated 7 June 2016. Electronic supplementary material The online version of this article (doi:10.1186/s13063-017-1929-0) contains supplementary material, which is available to authorized users
Abstracts from the 8th International Conference on cGMP Generators, Effectors and Therapeutic Implications
This work was supported by a restricted research grant of Bayer AG
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