4,764 research outputs found
OPTIMIST: A new conflict resolution algorithm for ACT-R.
Several studies have suggested recently that a more dynamic conflict resolution mechanism in the ACT-R cognitive architecture (Anderson & Lebiere, 1998) could improve the decision-making behaviour of cognitive models. This part of ACT-R theory is revisited and a new solution is proposed. The new algorithm (OPTIMIST) has been implemented as an overlay to the ACT-R architecture, and can be used as an alternative mechanism. The operation of the new algorithm is tested in a model of the classical Yerkes and Dodson experiement of animals' learning. When OPTIMIST is used, the resulting model fits the data better than the previous model (e.g. R2 (R squared) increases from .85 to .93 in one example)
Potential of the TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor for the monitoring of terrestrial chlorophyll fluorescence
Global monitoring of sun-induced chlorophyll fluorescence (SIF) is improving our knowledge about the photosynthetic functioning of terrestrial ecosystems. The feasibility of SIF retrievals from spaceborne atmospheric spectrometers has been demonstrated by a number of studies in the last years. In this work, we investigate the potential of the upcoming TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor satellite mission for SIF retrieval. TROPOMI will sample the 675–775 nm spectral window with a spectral resolution of 0.5 nm and a pixel size of 7 km × 7 km. We use an extensive set of simulated TROPOMI data in order to assess the uncertainty of single SIF retrievals and subsequent spatio-temporal composites. Our results illustrate the enormous improvement in SIF monitoring achievable with TROPOMI with respect to comparable spectrometers currently in-flight, such as the Global Ozone Monitoring Experiment-2 (GOME-2) instrument. We find that TROPOMI can reduce global uncertainties in SIF mapping by more than a factor of 2 with respect to GOME-2, which comes together with an approximately 5-fold improvement in spatial sampling. Finally, we discuss the potential of TROPOMI to map other important vegetation parameters at a global scale with moderate spatial resolution and short revisit time. Those include leaf photosynthetic pigments and proxies for canopy structure, which will complement SIF retrievals for a self-contained description of vegetation condition and functioning
Estudo preliminar do vermicomposto produzido a partir de lodo de esgoto doméstico e solo
O lodo de esgoto doméstico é um resÃduo gerado durante os processos de tratamento de esgoto, podendo ser estabilizado por diversos processos quÃmicos, fÃsicos e biológicos. O lodo de esgoto estabilizado (biossólido) não possui um destino final adequado e gera diversos problemas no sentido de sua disposição final. Dentre os muitos processos que visam à disposição do biossólido, destaca-se a reciclagem agrÃcola. A utilização da vermicompostagem como meio de estabilização do lodo de esgoto mostra-se como uma ferramenta útil na estabilização deste resÃduo. O processo de vermicompostagem apresentou caracterÃsticas fÃsico-quÃmicas satisfatórias para ser utilizado como técnica de estabilização do lodo de esgoto doméstico. O produto final apresentou potencial para ser utilizado na agricultura como fertilizante ou condicionador de solos.Domestic waste, a residue generated during sewage treatments, can be stabilized by many chemical, physical and biological processes. However, the stabilized waste (biosoil) currently lacks proper disposal alternatives. A new and promising disposal method is called farm recycling. The use of vermicomposting has shown to be useful as a mean to stabilize domestic waste. The biosoil achieved through this method exhibits high humidity-retaining capacity, good C/N relationship, as well as a satisfactory percentage of humic acid, thus being able to be incorporated into the soil as a conditioner and fertilizer
Intranasally Applied Neuropeptide S Shifts a High-Anxiety Electrophysiological Endophenotype in the Ventral Hippocampus towards a "Normal"-Anxiety One
The neurobiological basis of pathological anxiety and the improvement of its pharmacological treatment are a matter of intensive investigation. Here, using electrophysiological techniques in brain slices from animals of the high anxiety-related behavior (HAB) and normal anxiety-related behavior (NAB) mouse model, we show that basal neurotransmission at ventral hippocampal CA3-CA1 synapses is weaker in HAB compared to NAB mice. We further demonstrate that paired-pulse facilitation (PPF) and long-term potentiation (LTP) at these synapses are more pronounced in slices from HAB animals. Based on previous findings, we also examined whether intranasal delivery of neuropeptide S (NPS), which increasingly emerges as a potential novel treatment option for anxiety symptoms occurring in a variety of diseases like anxiety disorders, posttraumatic stress disorder, and major depression, impacts on the high-anxiety electrophysiological endophenotype in HAB mice. Strikingly, we detected enhanced basal neurotransmission and reduced PPF and LTP in slices from NPS-treated HAB animals. Collectively, our study uncovers a multifaceted high-anxiety neurophysiological endophenotype in the murine ventral hippocampus and provides the first evidence that an intranasally applied neuropeptide can shift such an endophenotype in an anxiety-regulating brain structure towards a "normal"-anxiety one
Double Spin Asymmetries A_NN and A_SS at sqrt{s}=200 GeV in Polarized Proton-Proton Elastic Scattering at RHIC
We present the first measurements of the double spin asymmetries A_NN and
A_SS at sqrt{s}=200 GeV, obtained by the pp2pp experiment using polarized
proton beams at the Relativistic Heavy Ion Collider (RHIC). The data were
collected in the four momentum transfer t range 0.01<|t|<0.03 (GeV/c)^2. The
measured asymmetries, which are consistent with zero, allow us to estimate
upper limits on the double helicity-flip amplitudes phi_2 and phi_4 at small t
as well as on the difference Delta(sigma_T) between the total cross sections
for transversely polarized protons with antiparallel or parallel spin
orientations.Comment: 13 pages with 3 figures. Final version accepted by Phys. Lett.
Potential of the TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor for the monitoring of terrestrial chlorophyll fluorescence
Global monitoring of sun-induced chlorophyll fluorescence (SIF) is improving our knowledge about the photosynthetic functioning of terrestrial ecosystems. The feasibility of SIF retrievals from spaceborne atmospheric spectrometers has been demonstrated by a number of studies in the last years. In this work, we investigate the potential of the upcoming TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor satellite mission for SIF retrieval. TROPOMI will sample the 675–775 nm spectral window with a spectral resolution of 0.5 nm and a pixel size of 7 km × 7 km. We use an extensive set of simulated TROPOMI data in order to assess the uncertainty of single SIF retrievals and subsequent spatio-temporal composites. Our results illustrate the enormous improvement in SIF monitoring achievable with TROPOMI with respect to comparable spectrometers currently in-flight, such as the Global Ozone Monitoring Experiment-2 (GOME-2) instrument. We find that TROPOMI can reduce global uncertainties in SIF mapping by more than a factor of 2 with respect to GOME-2, which comes together with an approximately 5-fold improvement in spatial sampling. Finally, we discuss the potential of TROPOMI to map other important vegetation parameters at a global scale with moderate spatial resolution and short revisit time. Those include leaf photosynthetic pigments and proxies for canopy structure, which will complement SIF retrievals for a self-contained description of vegetation condition and functioning
Quality of life in Type 1 (insulin-dependent) diabetic patients prior to and after pancreas and kidney transplantation in relation to organ function
Improvement of the quality of life in Type 1 (insulin-dependent) diabetic patients with severe late complications is one of the main goals of pancreas and/or kidney grafting. To assess the influences of these treatment modalities on the different aspects of the quality of life a cross-sectional study in 157 patients was conducted. They were categorized into patients pre-transplant without dialysis (n=29; Group A), pre-transplant under dialysis (n=44; Group B), post-transplant with pancreas and kidney functioning (n=31; Group C), post-transplant with functioning kidney, but insulin therapy (n=29; Group D), post-transplant under dialysis and insulin therapy again (n=15; Group E) and patients after single pancreas transplantation and rejection, with good renal function, but insulin therapy (n=9; Group F). All patients answered a mailed, self-administered questionnaire (217 questions) consisting of a broad spectrum of rehabilitation criteria. The results indicate a better quality of life in Groups C and D as compared to the other groups. In general the scores are highest in C, but without any significant difference to D. Impressive significant differences between C or D and the other groups were found especially in their satisfaction with physical capacity, leisure-time activities or the overall quality of life. The satisfaction with the latter is highest in C (mean±SEM: 4.0±0.2 on a 1 to 5-rating scale; significantly different from A: 3.1±0.1, B: 2.7±0.2 and E: 2.6±0.3; p<0.01), followed by D (3.8±0.2; significantly different from B and E; p<0.01). Group F shows a mean of 3.1±0.4, which is not significantly different from C. The percentages of patients in each group, who are not working: A: 38 %, B: 64 %, C: 74 %, D: 66 %, E: 87 % and F: 78 % indicate that there is no marked improvement in the vocational situation after successful grafting
Four years of Ulysses dust data: 1996 to 1999
The Ulysses spacecraft is orbiting the Sun on a highly inclined ellipse (, perihelion distance 1.3 AU, aphelion distance 5.4 AU). Between
January 1996 and December 1999 the spacecraft was beyond 3 AU from the Sun and
crossed the ecliptic plane at aphelion in May 1998. In this four-year period
218 dust impacts were recorded with the dust detector on board. We publish and
analyse the complete data set of both raw and reduced data for particles with
masses to g. Together with 1477 dust impacts
recorded between launch of Ulysses and the end of 1995 published earlier
\cite{gruen1995c,krueger1999b}, a data set of 1695 dust impacts detected with
the Ulysses sensor between October 1990 and December 1999 is now available. The
impact rate measured between 1996 and 1999 was relatively constant with about
0.2 impacts per day. The impact direction of the majority of the impacts is
compatible with particles of interstellar origin, the rest are most likely
interplanetary particles. The observed impact rate is compared with a model for
the flux of interstellar dust particles. The flux of particles several
micrometers in size is compared with the measurements of the dust instruments
on board Pioneer 10 and Pioneer 11 beyond 3 AU (Humes 1980, JGR, 85,
5841--5852, 1980). Between 3 and 5 AU, Pioneer results predict that Ulysses
should have seen five times more ( sized) particles than
actually detected.Comment: accepted by Planetary and Space Science, 22 pages, 8 figures (1
colour figure
Antimicrobial resistance of H. influenzae
Abstract From 1989 to 1995, a total of 391 Haemophilus influenzae isolates were recovered from the cerebrospinal fluid (CSF) of hospitalized patients in São Paulo, Brazil. The majority of strains were isolated from infants aged less than 5 years. Strains belonging to biotype I (64.7%), biotype II (34.5%) and biotype IV (0.76%) were detected. Ninety-nine percent of these strains were serotype b. Minimal inhibitory concentration (MIC) was determined for ampicillin, chloramphenicol and ceftriaxone. The ß-lactamase assay was performed for all strains. The rate of ß-lactamase producer strains ranged from 10 to 21.4% during a period of 7 years, with an overall rate of 13.8%. Of the 391 strains analyzed, none was ß-lactamase negative ampicillin resistant (BLNAR). A total of 9.7% of strains showed resistance to both ampicillin and chloramphenicol; however, 4% of them were resistant to ampicillin only and 2% to chloramphenicol. All strains were susceptible to ceftriaxone and the MIC 90 was 0.007 µg/ml, suggesting that ceftriaxone could be an option for the treatment of bacterial meningitis in pediatric patients who have not been screened for drug sensitivity
- …