428 research outputs found
Educational Assessment Reassessed
For decades, the assessment of educational entities--school systems, individual schools, and teachers--has evoked strong and sometimes violent emotions from the educational community, the general public, and their legislative representatives. In spite of attempts to codify standards for the evaluation of these entities, assessment experts remain denominationalized--often religiously so. Methods of assessment based on the use of standardized tests have come under intense fire in recent years with some critics going so far as to call for their complete elimination. Those who advocate alternative methods of assessment have become increasingly outspoken in establishing exclusive rights to the legitimate assessment paradigm. However, some of the most respected advocates of alternative assessment have taken a more moderate view, warning against an "either-or" mentality (Brandt, 1992, p. 35). Reflecting this more moderate perspective, this paper strongly advocates the use of multiple indicators of student learning, including those provided by standardized tests
Why Developers Participate in Open Source Software Projects: An Empirical Investigation
Our goal in this study is to provide insight into the motivational profiles of open source contributors. Adopting a functionalist view of motivation, we identify five functional dimensions from the literature on volunteerism that are relevant to the open source context and three functional dimensions from the literature on open source development. To assess the salience and relative strength of each functional explanation for open source participation, we conducted secure Web-based surveys of developers who participated in three large Apache open source projects. Applying exploratory factor analytic techniques to analyze the survey data collected from 122 Apache participants, we found 5 distinct factors underlying the motivation to participate in open source projects. We then used conjoint analysis to assess the relative importance of these underlying motivations. Results from the conjoint analysis indicate that while several dimensions are significant in explaining the motivation to participate in open source projects, the dominant motivations include increasing the contributor’s use value of the software (27 percent) followed by the recreational value of the task (19 percent) and the potential career impacts from participation (12 percent). This study contributes to the growing literature on open source software development by providing insight into the underlying motivational profiles of open source participation and by identifying the relative importance of different motivations within those profiles
Economic Incentives for Participating in Open Source Software Projects
Using the Internet as a basis for communication, collaboration, and storage of artifacts, the open source community is producing software of a quality that was previously thought to be achievable only by professional engineers following strict software development paradigms. This accomplishment is even more astounding as developers contribute to the source code without any remuneration. Open source leaders as well as academics have proposed theories about the motivation of open source developers that are rooted in diverse fields such as social psychology and anthropology. However, Lerner and Tirole (2000) argue that developer participation in open source projects may, in part, be explained by existing economic theory regarding career concerns. This research seeks to confirm or disconfirm the existence of economic returns to participation in open source development. Our findings suggest that greater open source participation per se, as measured in contributions made, is not associated with wage increases. However, a higher status in a merit-based ranking within the Apache Project is associated with significantly higher wages. This suggests that employers do not reward the gain in experience through open source participation as an increase in human capital. The results are also consistent with the notion that a high rank within the Apache Software Foundation is a credible signal of the productive capacity of a programmer
Copper in Wood Preservatives Delayed Wood Decomposition and Shifted Soil Fungal but Not Bacterial Community Composition
Copper-based fungicides are routinely used for wood and plant protection, which can lead to an enrichment of copper-tolerant microbial communities in soil. To investigate the effect of such wood preservatives on the soil fungal and bacterial community compositions, five different vineyard and fruit-growing soil environments were evaluated using incubation studies over time. Pine sapwood specimens were impregnated with either water or different biocide treatment solutions containing a mixture of copper, triazoles, and quaternary ammonium compounds (CuTriQAC), a mixture of triazoles and quaternary ammonium compounds (TriQAC), or copper alone (Cu). Specimens were incubated in soil from each sample site for 8, 16, 24, and 32 weeks. The effects of preservative treatment on the modulus of elasticity (MOE) of the wood specimens and on the soil fungal as well as bacterial community composition at the soil-wood interface were assessed by quantitative PCR and amplicon sequencing of the fungal internal transcribed spacer (ITS) region and bacterial 16S rRNA gene. Specimens impregnated with CuTriQAC and Cu showed decreased MOE and reduced fungal and bacterial copy numbers over time compared to those impregnated with water and TriQAC. Fungal but not bacterial community composition was significantly affected by wood preservative treatment. The relative abundance of members of the family Trichocomaceae compared to other genera increased in the presence of the Cu and CuTriQAC treatments at three sites, suggesting these to be Cu-tolerant fungi. In conclusion, the copper-containing treatments resulted in marginally increased MOE, lowered microbial gene copy numbers compared to those in the TriQAC and water treatments, and thus enhanced wood protection against soil microbial wood degradation
Resolving the Troubled IT-Business Relationship from a Cultural Perspective
This research investigates the effects of the culture of the information technology (IT) group on the relationship between business and IT professionals within two Australian organisations, one a public sector organisation, and the other a private company. The IT groups in these two organisations had many similar themes of culture. Both organisations reported a troubled IT-business relationship. This research investigates the effects of the themes of IT culture that surfaced in each organisation on six essential ingredients of an effective IT-business relationship, providing some suggestions for management to consider to improve their troubled IT-business business relationship
Use of Si-Phytoliths in depollution of mining areas in the Cerrado-Caatinga region, MG, Brazil
International audienceTreating of metal contaminated areas became a very important problem with increasing industrial and agricultural activities. Many of the used methods are very expensive, need intensive human interaction or have a very negative influence on the cleaned regions. The use of Si-Phytolites is a simple, low cost and a very effective way to obtain good results in low contaminated or as the final process in highly contaminated places. The method is based on the fact that a lot of plants produce Si-Phytolits and trap significant quantities of heavy metals in these amorphous to microcrystalline structures. The solubility of the Si-Phytolits under Brazilian soil conditions is lower than that of the heavy elements brought directly in the soil by the wash or fall out, or by degrading of organic parts of the plants at the upper part of surface. In this way, it is possible to retain liberation to the environment from short to longer periods and attend environmental laws and norms.Initial tests with different plants like Ricinus comunis L., Andropogon arundinaceus Willd., Zea Mays L., Brachiaria sp. L. and Saccharum officinarum L. planted on substrates with metal concentrations (Al, Fe, Mn, Ti, Zn, Cu, Pb, Cd, Ba, Hg, S) have shown that the plants absorbed elements and quantities in the different parts like leaves, roots, stems, flowers and fruits. This allows a selective use due to contamination varieties and a possible economic use of parts of the plants and an effective planning of the decontamination conditions
Control-oriented modeling of a LiBr/H2O absorption heat pumping device and experimental validation
Absorption heat pumping devices (AHPDs, comprising absorption heat pumps and
chillers) are devices that use thermal energy instead of electricity to
generate heating and cooling, thereby facilitating the use of waste heat and
renewable energy sources such as solar or geothermal energy. Despite this
benefit, widespread use of AHPDs is still limited. One reason for this is
partly unsatisfactory control performance under varying operating conditions,
which can result in poor modulation and part load capability. A promising
approach to tackle this issue is using dynamic, model-based control strategies,
whose effectiveness, however, strongly depend on the model being used. This
paper therefore focuses on the derivation of a viable dynamic model to be used
for such model-based control strategies for AHPDs such as state feedback or
model-predictive control. The derived model is experimentally validated,
showing good modeling accuracy. Its modeling accuracy is also compared to
alternative model versions, that contain other heat transfer correlations, as a
benchmark. Although the derived model is mathematically simple, it does have
the structure of a nonlinear differential-algebraic system of equations. To
obtain an even simpler model structure, linearization at an operating point is
discussed to derive a model in linear state space representation. The
experimental validation shows that the linear model does have slightly worse
steady-state accuracy, but that the dynamic accuracy seems to be almost
unaffected by the linearization. The presented new modeling approach is
considered suitable to be used as a basis for the design of advanced,
model-based control strategies, ultimately aiming to improve the modulation and
part load capability of AHPDs
Effect of induced hypothermia on respiratory parameters in mechanically ventilated patients
Aim: Mild hypothermia is increasingly applied in the intensive care unit. Knowledge on the effects of hypothermia on respiratory parameters during mechanical ventilation is limited. In this retrospective study, we describe the effect of hypothermia on gas exchange in patients cooled for 24 h after a cardiac arrest. Methods: Respiratory parameters were derived from electronic patient files from 65 patients at the start and end of the hypothermic phase and at every centigrade increase in body temperature until normo-temperature, including tidal volume, positive end expiratory pressure (PEEP), plateau pressure, respiratory rate, exhaled CO2 concentrations (etCO(2)) and FIO2. Static compliance was calculated as V-T/P-plateau - PEEP. Dead space ventilation was calculated as (PaCO2-etCO(2))/PaCO2. Results: During hypothermia, PaCO2 decreased, at unchanged PaCO2-etCO(2) gap and minute ventilation. During rewarming, PaCO2 did not change, while etCO(2) increased at unchanged minute ventilation. Dead space ventilation did not change during hypothermia, but lowered during rewarming. During hypothermia, PaO2/FIO2 ratio increased at unchanged PEEP levels. Respiratory static compliance did not change during hypothermia, nor during rewarming. Conclusion: Hypothermia possibly improves oxygenation and ventilation in mechanically ventilated patients. Results may accord with the hypothesis that reducing metabolism with applied hypothermia may be beneficial in patients with acute lung injury, in whom low minute ventilation results in severe hypercapnia. (C) 2010 Elsevier Ireland Ltd. All rights reserve
Workforce Characteristics, Perceptions, Stress, and Satisfaction among Staff in Green House and Other Nursing Homes
OBJECTIVE: To compare workforce characteristics and staff perceptions of safety, satisfaction, and stress between Green House (GH) and comparison nursing homes (CNHs).
DATA SOURCES/STUDY SETTING: Primary data on staff perceptions of safety, stress, and satisfaction from 13 GHs and 8 comparison NHs in 11 states; secondary data from human resources records on workforce characteristics, turnover, and staffing from 01/01/2011-06/30/2012.
STUDY DESIGN: Observational study.
DATA COLLECTION METHODS: Workforce data were from human resources offices; staff perceptions were from surveys.
PRINCIPAL FINDINGS: Few significant differences were found between GH and CNHs. Exceptions were GH direct caregivers were older, provided twice the normalized hours per week budgeted per resident than CNAs in CNHs or Legacy NHs, and trended toward lower turnover.
CONCLUSIONS: GH environment may promote staff longevity and does not negatively affect worker's stress, safety perceptions, or satisfaction. Larger studies are needed to confirm findings
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