299 research outputs found
Environmental and personality determinants of adolescents' evaluations of rewarding, neutral, and punishing power figures.
Thesis (Ph.D.)--Boston UniversityWithin the present research framework, some important determinants of an individual's responses to various types or power figures have been studied. On the basis of the Lewinian thesis that individual behavior is a product or the interaction between environmental and personality determinants, both these classes of variables were included in the investigation.
In the present research, power was defined as the ability of one person to reward or punish another person in a particular situation. However, it was theorized that the specific type of power possessed by a given power figure, i.e., power to reward or power to punish, would influence an individual's responses to that power figure. [TRUNCATED
ABIOTIC DEGRADATION OF IODOSULFURON-METHYL-ESTER IN AQUEOUS SOLUTION
The abiotic degradation of iodosulfuron-methyl-ester was investigated under both alkaline and acidic
pH conditions in the dark, and results showed it to be a rather stable molecule in neutral or slightly
alkaline environments. Photochemical reactions were studied using a high-pressure mercury arc lamp,
and results showed that direct phototransformation is possible under normal environmental conditions
(ì > 290 nm). High-performance liquid chromatography (HPLC-UV and HPLC-MS) analyses were
used to identify the degradates and to study the kinetics of photodecomposition and hydrolysis. Five
main products of iodosulfuron-methyl-ester degradation were tentatively identified, and one of them
(4-methoxy-6-methyl-1,3,5-triazin-2-amine) was confirmed using an authentic standard. Among the
phototransformation mechanisms, photosubstitution of the iodide atom by a hydroxyl group,
photodissociation of the N-S bond, and photoassisted hydrolysis were observed. The quantum
efficiencies (multiwavelength quantum yield) of the photodegradation under different conditions were
determined, and values of 0.054 ( 0.02 (pH 9.6), 0.08 ( 0.02 (pH 7), and 0.044 ( 0.008 (pH 5.3)
were obtained
Higher Derivative Corrections to Locally Black Brane Metrics
In this paper we generalize the construction of locally boosted black brane
space time to higher derivative gravities. We consider the Gauss-Bonnet term
(with coefficient ) as a toy example. We find the solution to the
corrected Einstein equations to first order in the boundary
derivative expansion. This allows us to find the corrections to the
boundary stress tensor in the presence of the Gauss-Bonnet term in the bulk
action. We therefore obtain the ratio of shear viscosity to entropy which
agrees with other methods of computation in the literature.Comment: 0+17 page
Multiple algebraisations of an elliptic Calogero-Sutherland model
Recently, Gomez-Ullate et al. (1) have studied a particular N-particle
quantum problem with an elliptic function potential supplemented by an external
field. They have shown that the Hamiltonian operator preserves a finite
dimensional space of functions and as such is quasi exactly solvable (QES). In
this paper we show that other types of invariant function spaces exist, which
are in close relation to the algebraic properties of the elliptic functions.
Accordingly, series of new algebraic eigenfunctions can be constructed.Comment: 9 Revtex pages, 3 PS-figures; Summary, abstract and conclusions
extende
FRCM retrofitting techniques for masonry walls: a literature review and some laboratory tests
The experimental characterisation of externally bonded composite materials as strengthening solutions for masonry structures, such as basalt textile reinforced mortar (BTRM) or fiber reinforced concrete (FRC), has been receiving increasing attention due to their outstanding mechanical performance. Several studies have been demonstrated the efficiency of this retrofitting solution for increasing the mechanical strength and the displacement capacity of masonry material. In this paper the state-of-art of the most relevant achievements in the experimental investigations and numerical analysis of retrofitted masonry wall have been critically reviewed. Firstly, a detailed collection of several experimental tests using different textile reinforced mortar and/or fiber reinforced mortar has been conducted. Special focus has been given to the test set-up and load configuration type adopted for experiments. Subsequently, several modelling techniques have been treated in order to detect the best approach simulating the interaction between reinforcement system and masonry ranging from macro and micro modelling, concentrated and diffused plasticity model and diverse constitutive laws. Finally, an overview of some original experimental outcomes from laboratory tests is presented. This results will play a major role in for the validation of the numerical models for the prediction of the shear strength and the ductile behavior of reinforced masonry that will be developed in a further step of this research
the tempio della consolazione in todi integrated geomatictechniques for a monument description including structuraldamage evolution in time
The Tempio della Consolazione in Todi (16th cent.) has always been one of the most significant symbols of the Umbrian landscape. Since the first times after its completion (1606) the structure has exhibited evidences of instability, due to foundation subsiding and/or seismic activity. Structural and geotechnical countermeasures have been undertaken on the Tempio and its surroundings from the 17th century until recent times. Until now a truly satisfactory analysis of the overall deformation and attitude of the building has not been performed, since the existing surveys record the overhangs of the pillars, the crack pattern or the subsidence over limited time spans. Describing the attitude of the whole church is in fact a complex operation due to the architectural character of the building, consisting of four apses (three polygonal and one semicircular) covered with half domes, which surround the central area with the large dome. The present research aims to fill the gap of knowledge with a global study based on geomatic techniques for an accurate 3D reconstruction of geometry and attitude, integrated with a historical research on damage and interventions and a geotechnical analysis. The geomatic survey results from the integration of different techniques: GPS-GNSS for global georeferencing, laser scanning and digital photogrammetry for an accurate 3D reconstruction, high precision total station and geometric leveling for a direct survey of deformations and cracks, and for the alignment of the laser scans. The above analysis allowed to assess the dynamics of the cracks occurred in the last 25 years by a comparison with a previous survey. From the photographic colour associated to the point cloud was also possible to map the damp patches showing on the domes intrados, mapping their evolution over the last years
Drug susceptibility testing of clinical isolates of streptococci and enterococci by the Phoenix automated microbiology system
<p>Abstract</p> <p>Background</p> <p>Drug resistance is an emerging problem among streptococcal and enterococcal species. Automated diagnostic systems for species identification and antimicrobial susceptibility testing (AST) have become recently available. We evaluated drug susceptibility of clinical isolates of streptococci and enterococci using the recent Phoenix system (BD, Sparks, MD). Diagnostic tools included the new SMIC/ID-2 panel for streptococci, and the PMIC/ID-14 for enterococci. Two-hundred and fifty isolates have been investigated: β-hemolytic streptococci (n = 65), <it>Streptococcus pneumoniae </it>(n = 50), viridans group streptococci (n = 32), <it>Enterococcus faecium </it>(n = 40), <it>Enterococcus faecalis </it>(n = 43), other catalase-negative cocci (n = 20). When needed, species ID was determined using molecular methods. Test bacterial strains were chosen among those carrying clinically-relevant resistance determinants (penicillin, macrolides, fluoroquinolones, glycopeptides). AST results of the Phoenix system were compared to minimal inhibitory concentration (MIC) values measured by the Etest method (AB Biodisk, Solna, Sweden).</p> <p>Results</p> <p>Streptococci: essential agreement (EA) and categorical agreement (CA) were 91.9% and 98.8%, respectively. Major (ME) and minor errors (mE) accounted for 0.1% and 1.1% of isolates, respectively. No very major errors (VME) were produced. Enterococci: EA was 97%, CA 96%. Small numbers of VME (0.9%), ME (1.4%) and mE (2.8%) were obtained. Overall, EA and CA rates for most drugs were above 90% for both genera. A few VME were found: a) teicoplanin and high-level streptomycin for <it>E. faecalis</it>, b) high-level gentamicin for <it>E. faecium</it>. The mean time to results (± SD) was 11.8 ± 0.9 h, with minor differences between streptococci and enterococci.</p> <p>Conclusion</p> <p>The Phoenix system emerged as an effective tool for quantitative AST. Panels based on dilution tests provided rapid and accurate MIC values with regard to clinically-relevant streptococcal and enterococcal species.</p
Recommended from our members
Impact of the COVID-19 pandemic on midwifery-led service provision in the United Kingdom in 2020-21: Findings of three national surveys
Background
The COVID-19 pandemic required all healthcare systems to adapt quickly. There is some evidence about the impact of the pandemic on United Kingdom maternity services overall, but little is known about the impact on midwifery-led services, including midwifery units and home birth services.
Objective
To describe changes to midwifery-led service provision in the United Kingdom and the Channel Islands during the COVID-19 pandemic.
Design
Three national surveys were circulated using the United Kingdom Midwifery Study System (UKMidSS) and the Royal College of Midwives (RCM) Heads and Directors of Midwifery Network. The UKMidSS surveys took place in wave 1 (April to June 2020) and in wave 2 (February to March 2021). The RCM survey was conducted in April 2020.
Findings
The response rate to the UKMidSS surveys was 84% in wave 1 and 70% in wave 2, while 48% of Heads and Directors of Midwifery responded to the RCM survey. Around 60% of midwifery units reported being open as usual in wave 1, with the remainder affected by closures. Fewer unit closures (15%) were reported in the wave 2 survey. Around 40% of services reported some reduction in home birth services in wave 1, compared with 15% in wave 2. The apparent impact of the pandemic varied widely across the four nations of the United Kingdom and within the English regions.
Conclusions
The pandemic led to increased centralisation of maternity care and the disruption of midwifery-led services, especially in the first wave. Further research should focus on the reasons behind closures, the regional variation and the impact on maternity care experience and outcomes
AdS_7/CFT_6, Gauss-Bonnet Gravity, and Viscosity Bound
We study the relation between the causality and the positivity of energy
bounds in Gauss-Bonnet gravity in AdS_7 background and find a precise
agreement. Requiring the group velocity of metastable states to be bounded by
the speed of light places a bound on the value of Gauss-Bonnet coupling. To
find the positivity of energy constraints we compute the parameters which
determine the angular distribution of the energy flux in terms of three
independent coefficients specifying the three-point function of the
stress-energy tensor. We then relate the latter to the Weyl anomaly of the
six-dimensional CFT and compute the anomaly holographically. The resulting
upper bound on the Gauss-Bonnet coupling coincides with that from causality and
results in a new bound on viscosity/entropy ratio.Comment: 21 page, harvmac; v2: reference adde
- …