29,806 research outputs found
Ethnography, ethics and ownership of data
© The Author(s) 2019. Establishing trust and obtaining informed consent with participants is reliant upon on a process whereby unequally positioned agents constantly re-negotiate (mis)trust and consent during ethnographic encounters. All research has been increasingly subject to an intensification in ethical regulation, within a context whereby Eurocentric norms and ethical guidelines arguably diminish individual accountability under the guise of quasi-contractual relationships. This phenomenon has particular implications for ethnography and its management of ethics, given its intimate, longitudinal and receptive nature. Two expert ethnographers working with children and young people draw upon their work to reveal how issues of informed consent and data ownership can shift and be a source of tension and unequal power dynamics. The ethnographer requires autonomy while managing ethics soundly in situ to work within the messiness and unpredictability of participants’ everyday lives
Invariant states and rates of Convergence for a critical fluid model of a processor sharing queue
This paper contains an asymptotic analysis of a fluid model for a heavily
loaded processor sharing queue. Specifically, we consider the behavior of
solutions of critical fluid models as time approaches \infty. The main theorems
of the paper provide sufficient conditions for a fluid model solution to
converge to an invariant state and, under slightly more restrictive
assumptions, provide a rate of convergence. These results are used in a related
work by Gromoll for establishing a heavy traffic diffusion approximation for a
processor sharing queue
Effect of Carex rostrata on seasonal and interannual variability in peatland methane emissions
Peatlands are a large natural source of atmospheric methane (CH4), and the sedge Carex rostrata plays a critical role in the production, oxidation, and transport of CH4 in these systems. This 4 year clipping experiment examined the changes in CH4 emissions from a temperate peatland after removing all aboveground C. rostrata biomass. Methane fluxes, dissolved CH4, and environmental variables were measured during spring, summer, and fall from 2008 to 2011. Clipping and removing the C. rostrata leaves and stems caused an immediate decrease in CH4 emissions that persisted over 4 years of this study. There was a strong seasonal trend in CH4 flux, with the largest treatment effects occurring during the fall months when the sedges were senescing. As expected, there was a strong positive correlation between C. rostrata green-leaf area and CH4 flux, implying that the presence of C. rostrata increases CH4 emissions from this peatland. Large interannual variability in vegetation distribution and biomass, water table depth, and temperature was observed in this study, indicating the importance of multiyear studies for understanding the interactions among these factors to determine how they could be incorporated into biogeochemical models to predict CH4 emissions under changing environmental conditions
Determination of silicate liquid thermal expansivity using dilatometry and calorimetry
A method for the determination of relaxed silicate liquid molar volume and expansivity at temperatures just above the glass transition is discussed. The method involves the comparison of heat capacity and molar expansivity in the glass transition region. Glassy and liquid heat-capacity data are obtained using differential scanning calorimetry, and glassy thermal expansion data are obtained using scanning dilatometry. The molar expansivity of the liquid is calculated by a fictive temperature normalization of the relaxation behavior of both the heat capacity and the molar expansivity in the glass transition region, with the normalized heat capacity curve being used to extend the dilatometric data into the liquid temperature range. This comparison is based upon the assumed equivalence of the parameters describing the relaxation of volume and enthalpy. The molar expansivity of relaxed sodium trisilicate (Na2Si3O7) has been determined in this manner at temperatures above the glass transition temperature. This low-temperature determination of liquid molar expansivity has been tested against high-temperature liquid expansivity data obtained from high temperature Pt double bob Archimedean buoyancy measurements. The low-temperature molar expansivity (26.43±0.83xl0~4 cm3 mole"lßC_1 at 540°C) determined in this manner agrees within error with the high-temperature molar expansivity (23.29±1.39xl0~4 cm3 mole^ºC1 at 1400°C). This dilatometric/calorimetric method of liquid molar expansivity determination greatly increases the temperature range accessible for thermal expansion measurements. A weighted linear fit to the combined low and high temperature volume data gives a molar expansivity of 23.0010.25x10^ cm3 mole^ºC"1. The volume-temperature relationship thus derived reproduces the measured volumes from both dilatometry and densitometry with a RMSD value of 0.033 cm3 mole"1 or 0.14%. This represents a substantial increase in precision, which is especially important for liquids whose high liquidus temperatures restrict the temperature range accessible to liquid volume determinations
A volume temperature relationship for liquid GeO2 and some geophysically relevant derived parameters for network liquids
The thermal expansivity of liquid GeO2 at temperatures just above the glass transition has been obtained using a combination of scanning calorimetry and dilatometry. The calorimetric and dilatometric curves of c p and dV/dT are normalized to the temperature derivative of fictive temperature versus temperature using the method of Webb et al. (1992). This normalization, based on the equivalence of relaxation parameters for volume and enthalpy, allows the completion of the dilatometric trace across the glass transition to yield liquid expansivity and volume. The values of liquid volume and expansivity obtained in this study are combined with high temperature densitometry determinations of the liquid volume of GeO2 by Sekiya et al. (1980) to yield a temperature-volume relation for GeO2 melt from 660 to 1400 °C. Liquid GeO2 shows a strongly temperature-dependent liquid molar expansivity, decreasing from 20.27 × 10–4 cm3 mol–1°C–1 to 1.97 × 10–4cm3 mol–1 °C–1 with increasing temperature. The coefficient of volume thermal expansion ( v ) decreases from 76.33 × 10–6 °C–1 to 2.46 × 10–6 °C–1 with increasing temperature. A qualitatively similar volume-temperature relationship, with v decreasing from 335 × 10–6 °C–1 to 33 × 10–6 °C–1 with increasing temperature, has been observed previously in liquid B2O3. The determination of the glass transition temperature, liquid volume, liquid and glassy expansivities and heat capacities in this study, combined with compressibility data for glassy and liquid GeO2 from the literature (Soga 1969; Kurkjian et al. 1972; Scarfe et al. 1987) allows the calculation of the Prigogine-Defay ratio (), c p -c v and the thermal Grüneisen parameter ( th) for GeO2. From available data on liquid SiO2 it is concluded that liquid GeO2 is not a good analog for the low pressure properties of liquid SiO2
Temperature-dependent thermal expansivities of silicate melts: The system anorthite-diopside
The temperature-dependent thermal expansivities of melts along the join anorthite-diopside have been determined on glassy and liquid samples using a combination of calorimetry, dilatometry, and Pt double bob Archimedean densitometry.
Supercooled liquid volumes and molar thermal expansivities were determined using scanning calorimetric and dilatometric measurements of properties in the glass region and their behavior at the glass transition. The extraction of low-temperature liquid molar expansivities from dilatometry /calorimetry is based on an assumed equivalence of the relaxation of volume and enthalpy at the glass transition using a method developed and tested by Webb et al. (1992). This method corrects for transient effects at the glass transition which can lead to serious overestimates of liquid thermal expansivity from “peak” values. Superliquidus volumes were determined using double Pt bob Archimedean densitometry at temperatures up to 1650°C.
The resulting data for liquid volumes near glass transition temperatures (810–920°C) and at superliquidus temperatures (1400–1650°C) are combined to yield thermal expansivities over the entire supercooled and stable liquid range. The molar expansivities are, in general, temperature dependent. The temperature-dependence of thermal expansivity increases from anorthite to diopside composition. The thermal expansivity of anorthite is essentially temperature independent, whereas that of diopside decreases by 50% between 800 and 1500°C, with the consequence that the thermal expansivities of the liquids in the anorthite-diopside system converge at high temperature
The effect of P2O5 on the viscosity of haplogranitic liquid
The effect of P2O5 on the viscosity of a haplogranitic (K2O-Na2O-Al2O3-SiO2) liquid has been determined at 1 atm pressure in the temperature interval of 700 - 1650°C. Viscosity measurements of a haplogranite, haplogranite + 5.1 wt.% P2O5 and haplogranite + 9.5 wt.% P2O5 have been performed using the concentric cylinder and micropenetration methods. The viscosity of haplogranite liquid decreases with the addition of P2O5 at all temperatures investigated. The viscosity decrease is nonlinear, with the strongest decrease exhibited at low P2O5 concentration. The temperature-dependence of the viscosity of all the investigated liquids is Arrhenian, as is the case for P2O5 liquid. The Arrhenian activation energy is slightly lower in the P2O5-bearing liquids than in the P2O5-free haplogranite with the result that the effect of P2O5 on viscosity is a (weak) function of temperature. At temperatures corresponding to the crystallization of phosphorus-rich granitic and pegmatitic systems the addition of 1 wt.% of P2O5 decreases the viscosity 0.2 log10 units. The effect of P2O5 on haplogranitic melt viscosity is much less than that for B2O3, F2O−1 on the same melt composition (Dingwell et al., 1992 and this study). This implies that P2O5 concentration gradients in high-silica melts during, for example, phosphate mineral growth or dissolution in granitic magmas, will not significantly influence melt viscosity
Effectiveness of Home Care Nursing Program (HCNP) on The activities of daily living of stroke patients
Home Care Nursing Program (HCNP) at HUKM was started in 1998 and
evaluation of the program was required. The objective of this study is to evaluate the
effectiveness of HCNP on stroke rehabilitation at HUKM. A retrospective study using a
matched pair design involving 69 stroke patients admitted to HUKM from August 1998 to
December 2000 was carried out. The participants of this study were the HCNP group
(n=35), and Non- HCNP (n=34). The matching was based on five criteria; age, sex,race, data of admission and severity of disability. The HCNP group was identified through
data at the HCNP unit and their medical reports were traced. For the Non-HCNP group,
the participants were identified based on criteria which were similar to that of the HCNP
group. Based on the criteria identified, there was no significant difference between the two
groups. The Activities of Daily Living was measured using the Modified Barthel Index twice;
once on admission (based on record) and one post stroke. The t-test was applied to
parametric data and non-parametric data; Chi-square was used to detect any significant
relationships between the scores of the two groups. Results showed no significant
difference (p=0.1990) in ADL on admission and ADL post stroke patients between the two groups. However, there were significant difference (HCNP p=0.000 and Non-HCNP p=0.000) in ADL on admission and post stroke for stroke patients who sought alternative treatment compared to those who had no
A new paradigm for SpeckNets:inspiration from fungal colonies
In this position paper, we propose the development of a new biologically inspired paradigm based on fungal colonies, for the application to pervasive adaptive systems. Fungal colonies have a number of properties that make them an excellent candidate for inspiration for engineered systems. Here we propose the application of such inspiration to a speckled computing platform. We argue that properties from fungal colonies map well to properties and requirements for controlling SpeckNets and suggest that an existing mathematical model of a fungal colony can developed into a new computational paradigm
Review of research in primary reading at Boston University: 1954-1959.
Thesis (Ed.M.)--Boston Universit
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