5,799 research outputs found
Post-Processing Precise Point Positioning Solutions with Parameter Optimization
Precise Point Positioning (PPP) technique can offer position solutions with centimeter-level accuracy by fusing precise satellite orbits and clocks with un-differenced, dual-frequency, pseudo-range, and carrier-phase observables. PPP presents a compelling alternative to Differential Global Positioning Systems, with the benefit that it only requires a single receiver and does not require simultaneous observations from many stations, making it appealing for ongoing research on hydro-graphic survey applications. The National Oceanic and Atmospheric Administration has been working on a buoy system tracked with a Global Positioning Systems receiver and Inertial Measurement Unit sensor using the PPP technique. In the interest of obtaining accurate measurements, this data is post-processed using a software package for position navigation with tight Inertial Navigation System capabilities developed by the Jet Propulsion Laboratory, this is GNSS Inferred Positioning Systems (GIPSYx). GIPSYx Software allows finely controllable user inputs for selectable models and configurations. This flexibility allows fitting the right models for different data sources but requires a tuning process to find suitable configurations. A processing strategy for buoy data with GIPSYx positioning software is described and a method to assess solutions to automatically optimize the process of finding these manually tuned model parameters is provided. Other data sources are considered to generalize this method and prove the concept of optimizing positioning software configurations from output solution evaluation using black-box optimization
XMM-Newton and Deep Optical Observations of the OTELO fields: the Groth-Westphal Strip
OTELO (OSIRIS Tunable Emission Line Object Survey) will be carried out with
the OSIRIS instrument at the 10 m GTC telescope at La Palma, and is aimed to be
the deepest and richest survey of emission line objects to date. The deep
narrow-band optical data from OSIRIS will be complemented by means of
additional observations that include: (i) an exploratory broad-band survey that
is already being carried out in the optical domain, (ii) FIR and sub-mm
observations to be carried with the Herschel space telescope and the GTM, and
(iii) deep X-Ray observations from XMM-Newton and Chandra.Here we present a
preliminary analysis of public EPIC data of one of the OTELO targets,the
Groth-Westphal strip, gathered from the XMM-Newton Science Archive (XSA). EPIC
images are combined with optical BVRI data from our broadband survey carried
out with the 4.2m WHT at La Palma. Distance-independent diagnostics (involving
X/O ratio, hardness ratios, B/T ratio) are tested.Comment: 2 pages, 2 figures, uses graphicx package. To appear in proceedings
of "The X-Ray Universe 2005", San Lorenzo del Escorial, Spain, September
26-30, 200
TRADE-OFFS BETWEEN ECONOMIC EFFICIENCY AND CONTAMINATION BY COFFEE PROCESSING A BIOECONOMIC MODEL AT THE WATERSHED LEVEL IN HONDURAS
In Honduras, traditional coffee processing is the cause of two major problems: poor coffee quality and contaminated water. In this paper we present a method that determines the trade-off between economic efficiency and contamination in a Honduran sub-watershed. The method is a bioeconomic model based on mathematical programming that stimulates the functioning of the interlinked economic and ecological processes in the sub-watershed. We compare various scenarii where the model is given the possibility of replacing traditional coffee processing plants with a network of improved ecological plants. For different levels of contamination the model determines the optimal location and size of new coffee processing plants along river streams by minimizing transport, variable and fixed costs. The restrictions of the system are the volume of wet coffee to be processed, the available stream water, and in the alternative scenarii, investment capital and contaminant concentration in the river. We apply the method to a typical sub-watershed in the hillsides of western Honduras and show that coffee quality can be improved and contamination can be reduced substantially at a relatively low cost.coffee, environment, water quality, mathematical programming, transport cost, spatial analysis, watershed, Honduras., Environmental Economics and Policy,
Effects of regional climate model spatial resolution on hydrological modelling of summer-fall floods in southern Quebec
This study aims to evaluate the effects of the Canadian Regional Climate Model’s (CRCM) spatial resolution on summer-fall floods simulation. Seven different climate simulations issued from the fourth and the fifth version of the CRCM are employed. Four different climate simulations issued from the fourth version of the CRCM (CRCM4) are compared. They are composed of two simulations driven by the Canadian General Circulation Model (CGCM) and two driven by the ERA-40c reanalysis using grid meshes of 15 km and 45 km resolutions for each driver. Three climate simulations issued from the fifth version of the CRCM (CRCM5) driven by the ERA-Interim at 0.44° (≈ 48 km), 0.22° (≈ 24 km) and 0.11° (≈ 12 km) spatial resolutions are used. All comparisons are evaluated on a daily time-step for the 1961-1990 period (for CRCM4) and for the 1981-2010 period (for CRCM5).
These seven simulations (four from CRCM4 and three from CRCM5) are used as input for two hydrological models of varying complexity (HSAMI and MOHYSE). Each model is calibrated using three different objective functions based on the Kling-Gupta Efficiency criteria (KGE) to target the summer-fall floods. Three seasonal indices are used to evaluate the CRCM outputs: bias (temperature), relative bias (precipitation) and variances ratio (temperature and precipitation). In an attempt to evaluate the effects of the spatial resolution on the hydrological modelling of summer-fall floods, streamflow simulations are generated using the seven climate datasets. The generated climate-driven streamflow simulations are analysed by two performance statistics: the seasonal values of KGE and the seasonal relative biases. Summer-fall floods are evaluated through the use of four flood indicators, the 2-year, 5-year, 10-year and 20-year return periods.
The results revealed an impact of spatial resolution on climate model outputs (temperature and precipitation) and on summer-fall floods simulation by the two hydrological models and the three different calibration approaches, although this can be due to other elements such as domain size and climate model driver. The flood indicators demonstrate an increase on the summer-fall floods return periods with increasing resolution from both hydrological models. On the other hand the hydrological models structure and the calibration approaches did not show significant impacts on the summer-fall floods. The results highlight the need for further research to assess the additional uncertainty due to the impacts of the climate simulations spatial resolution on hydrological studies
Biosimilars in rheumatology: what the clinician should know
Biosimilars are now a reality in rheumatology. Although analytical and non-clinical procedures to establish similarity have evolved significantly, clinical trials demonstrating equivalent efficacy and safety are absolutely required for all biosimilars. The design of such trials, including equivalence and non-inferiority statistical approaches, are discussed. Clinical evidence on biosimilars that have been approved recently or are presently being developed for use in rheumatology is also reviewed and contrasted with that available for biomimics (or intended copies), which are non-innovator biologics that are marketed in several countries but have not undergone review according to a regulatory pathway for biosimilars
Social Inclusion: The Higher Education Sector in Chile and in the United Kingdom
The Higher Education (HE) systems of Chile and the UK are compared in terms of the
‘massification’ (Altbach, 1989) and the relevance and adequacy of the private-public
provision mix. Dissimilar, each country has tried to build social inclusion into HE
outreach at the same time as allowing participation of the private sector. Also
included in the research are a) the role of social capital as a positive contribution for
the social and economic development; b) the current state of social inequality in
access to HE; and c) an in-depth analysis of the implications of both state and private
roles over social inclusion in HE. Outreach programmes from each country, the
Propedeutico in Chile and Aimhigher in the UK, are also analysed for lessons learned
OSIRIS Software: The Mask Designer Tool
OSIRIS is a Day One instrument that will be available at the 10m GTC
telescope which is being built at La Palma observatory in the Canary Islands.
This optical instrument is designed to obtain wide-field narrow-band images
using tunable filters and to do low-resolution spectroscopy in both long-slit
and multislit modes. For the multislit spectroscopy mode, we have developed a
software to assist the observers to design focal plane masks. In this paper we
describe the characteristics of this Mask Designer tool. We discuss the main
design concepts, the functionality and particular features of the software.Comment: 6 figures; accepted for publication in Experimental Astronom
Atypical Klebsiella Species in a Third Level Hospital as Cause of Neonatal Infection
Aportamos una propuesta para analizar la agresividad de un patógeno en relación a la resistencia y sensibilidad antimicrobianas encontradas.Background: The opportunistic pathogen Klebsiella pneumoniae is one of the main causes of pediatric bacterial blood stream infections (BSI), which is complicated with sepsis and high mortality. Objectives: To identify atypical Klebsiella species affecting a sample of infected neonates with low antimicrobial response. Methods: Multidrug resistant blood cultures for Klebsiella from a Neonatal Service, were submitted to molecular identification by sequencing analysis of 16S ribosomal RNA. Results: Themean age of the newborns was 14.7±5.6 days. A total of 6 out of 8 cases were sepsis, 1 case of pneumonia, and 1 a catheterrelated infection. The molecular identification showed 3 cases of K. pneumoniae subsp. ozaenae, 2 of K. pneumoniae and K. variicola, and 1 case of K. oxytoca. The highest antimicrobial resistance was against cephalosporins and Trimethoprim/sulfamethoxazole. Conclusions: Klebsiella pneumoniae subsp. ozaenae was responsible for multidrug resistant strains of Klebsiella even in 37.5% of cases. In our clinical setting, the use of Amikacin and carbapenems are still useful to treat neonatal infections by Klebsiella even against K. variicola, which is the most resistantCiprés Grupo Médico S.C. (CGM)
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