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1.
Front Psychol ; 13: 910206, 2022.
Article in English | MEDLINE | ID: mdl-35769731

ABSTRACT

Employee attitudes to change are key predictors of organizational change success. In this article, change engagement is defined as the extent to which employees are enthusiastic about change, and willing to actively involve themselves in ongoing organizational change. A model is tested showing how change-related organizational resources (e.g., senior leader support for change and organizational change climate) influence change engagement, in part through their influence on change-related job resources. Confirmatory Factor Analysis (CFA) and Structural Equations Modeling (SEM) results yielded good fit to the data in two independent samples: 225 Australian working professionals, and 201 employees from a Prolific sample. As proposed, change-related organizational resources (modeled as a higher order construct) were positively associated with higher order change-related job resources. Change-related job resources were positively associated with change engagement. In contrast to expectations, organizational resources were not directly associated with change engagement. Instead, change-related job resources fully mediated the relationship. Overall, the study provides empirical support for new measures of organizational change resources and employee change engagement. By drawing from well-established models in the change and engagement literatures, the study provides a promising research direction for those interested in further understanding positive employee attitudes to organizational change. Practical implications and future research opportunities are discussed.

2.
Front Psychol ; 11: 531944, 2020.
Article in English | MEDLINE | ID: mdl-33240144

ABSTRACT

The purpose of this conceptual article is to introduce the construct of change engagement and a model that also consists of change-related organizational resources, change-related job resources and demands, and change-related personal resources. We propose that change engagement is a construct that is theoretically and practically useful for understanding employee reactions to and adoption of organizational change. Drawing from existing models of employee engagement, we add to the change literature by identifying salient change-related organizational resources, job resources, job demands, and personal resources in a previously validated framework that brings together the literature on both engagement and change. By using the proposed change engagement framework, practitioners and researchers will potentially be able to effectively diagnose, manage, and optimize employee change readiness and enthusiasm for ongoing change. Furthermore, the change engagement model (CEM) provides practitioners and researchers with a comprehensive and practically useful model that will be easy to comprehend and communicate. The model can be applied to the planning, implementation, and evaluation of discrete change initiatives, as well as to ongoing change. The model is therefore well-suited to contemporary organizational contexts where change is widely recognized to be a constant.

3.
PLoS One ; 13(2): e0193166, 2018.
Article in English | MEDLINE | ID: mdl-29474448

ABSTRACT

Ancestral Polynesian society is the formative base for development of the Polynesian cultural template and proto-Polynesian linguistic stage. Emerging in western Polynesia ca 2700 cal BP, it is correlated in the archaeological record of Tonga with the Polynesian Plainware ceramic phase presently thought to be of approximately 800 years duration or longer. Here we re-establish the upper boundary for this phase to no more than 2350 cal BP employing a suite of 44 new and existing radiocarbon dates from 13 Polynesian Plainware site occupations across the extent of Tonga. The implications of this boundary, the abruptness of ceramic loss, and the shortening of duration to 350 years have substantive implications for archaeological interpretations in the ancestral Polynesian homeland.


Subject(s)
Archaeology , Ceramics/history , Culture , History, Ancient , History, Medieval , Humans , Polynesia
4.
Water Res ; 40(13): 2503-10, 2006 Jul.
Article in English | MEDLINE | ID: mdl-16814840

ABSTRACT

Two expanded granular sludge bed-anaerobic filter (EGSB-AF) bioreactors (3.38 l active volume) were used to directly compare psychrophilic (15 degrees C), anaerobic digestion (PAD) to mesophilic (37 degrees C) anaerobic digestion (MAD) for the treatment of a brewery wastewater (chemical oxygen demand (COD) concentration of 3,136+/-891 mg l(-1)). Bioreactor performance was evaluated by COD removal efficiency and biogas yields at a range of hydraulic and organic loading rates. Specific methanogenic activity (SMA) assays were also employed to investigate the activity of the biomass in the bioreactors. No significant difference in the COD removal efficiencies (which ranged from 85-93%) were recorded between PAD and MAD during the 194-d trial at maximum organic and hydraulic loading rates of 4.47 kg m(-3) day(-1) and 1.33 m(3) m(-3) day(-1), respectively. In addition, the methane content (%) of the biogas was very similar. The volumetric biogas yield from the PAD bioreactor was approximately 50% of that from the MAD bioreactor at an organic loading rate of 4.47 kg COD m(-3) day(-3) and an applied liquid up-flow velocity (V(up)) of 2.5 m h(-1). Increasing the V(up) in the PAD bioreactor to 5 m h(-1) resulted in a volumetric biogas production rate of approximately 4.1 l d(-1) and a methane yield of 0.28 l CH(4) g(-1) COD d(-1), which were very similar to the MAD bioreactor. Significant and negligible biomass washout was observed in the mesophilic and psychrophilic systems, respectively, thus increasing the sludge loading rate applied to the former and underlining the robustness of the latter, which appeared underloaded. A psychrotolerant mesophilic, but not truly psychrophilic, biomass developed in the PAD bioreactor biomass, with comparable maximum SMA values to the MAD bioreactor biomass. PAD, therefore, was shown to be favourably comparable to MAD for brewery wastewater treatment and biogas generation.


Subject(s)
Bacteria, Anaerobic/metabolism , Biodegradation, Environmental , Industrial Microbiology/methods , Waste Disposal, Fluid/methods , Water Purification/methods , Biomass , Bioreactors/microbiology , Efficiency
5.
Article in English | MEDLINE | ID: mdl-16702065

ABSTRACT

Low-temperature or psychrophilic (<20 degrees C) anaerobic biological treatment of simple industrial wastewaters has recently been proven feasible as an alternative to more expensive mesophilic (ca. 37 degrees C) technology. We implemented novel expanded granular sludge bed (EGSB)-based bioreactor designs for 27 psychrophilic anaerobic digestion (PAD) trials for the treatment of a broad range of simple and complex synthetic wastewaters representing dairy, food-processing and pharmaceutical sector effluents. A variety of operating parameters, such as hydraulic retention time, organic and volumetric loading rates and upflow velocity, were tested. Chemical oxygen demand (COD) removal efficiencies were recorded, which were comparable to previous mesophilic trials. Specific methanogenic activity, toxicity and biodegradability batch assays were employed to monitor the metabolic capabilities of microbial consortia in anaerobic reactors. The prevalence of psychrotolerant communities was observed and psychrophilic populations were detected in two of the reactors. The potential of PAD with respect to global sustainable development is discussed.


Subject(s)
Bioreactors , Cold Temperature , Industrial Microbiology/methods , Sewage/microbiology , Waste Disposal, Fluid/methods , Anaerobiosis , Biodegradation, Environmental , Biomass , Methane/chemistry , Methane/metabolism , Oxygen/chemistry , Oxygen/metabolism , Sewage/chemistry , Time Factors
6.
Article in English | MEDLINE | ID: mdl-16702066

ABSTRACT

The microbial ecology of a range of anaerobic biological assemblages (granular sludge) from full- and laboratory-scale wastewater treatment bioreactors, and of crop-growing and peat soils, was determined using a variety of 16S rRNA gene-based techniques, including clone library, terminal restriction fragment length polymorphism (TRFLP) and denaturing gradient gel electrophoresis (DGGE) analyses. Fluorescent in situ hybridization (FISH) using 16S rRNA gene-targeted probes was employed to complete a "full-cycle rRNA approach" with selected biomass. Genetic fingerprinting (TRFLP and DGGE) was effectively used to elucidate community structure-crop relationships, and to detect and monitor trends in bioreactor sludge and specific enrichment cultures of peat soil. Greater diversity was resolved within bacterial than within archaeal communities, and unexpected reservoirs of uncultured Crenarchaeota were detected in sludge granules. Advanced radiotracer incubations and micro-beta imaging were employed in conjunction with FISH to elucidate the eco-functionalism of these organisms. Crenarchaeota clusters were identified in close associated with methanogenic Archaea and both were localised with acetate uptake in biofilm structure.


Subject(s)
Ecosystem , RNA, Ribosomal, 16S/genetics , Sewage/microbiology , Soil Microbiology , Waste Disposal, Fluid/methods , Archaea/classification , Archaea/genetics , Archaea/isolation & purification , Archaea/metabolism , Bacteria/classification , Bacteria/genetics , Bacteria/isolation & purification , Bacteria/metabolism , Base Sequence , Biofilms , Biomass , Bioreactors/microbiology , Crenarchaeota/genetics , Crenarchaeota/isolation & purification , Crenarchaeota/metabolism , DNA, Archaeal/analysis , DNA, Archaeal/genetics , DNA, Bacterial/analysis , DNA, Bacterial/genetics , Electrophoresis, Agar Gel , Methane/chemistry , Methane/metabolism , Phylogeny , RNA, Ribosomal, 16S/analysis
7.
Water Res ; 40(5): 1009-17, 2006 Mar.
Article in English | MEDLINE | ID: mdl-16488461

ABSTRACT

Anaerobic digestion in the psychrophilic (< 20 degrees C) or sub-mesophilic temperature range has recently been proven as an effective treatment option for the mineralization of a wide variety of problematic wastewaters. In this study, an expanded granular sludge bed-anaerobic filter (EGSB-AF) bioreactor was seeded with a full-scale, mesophilic sludge and employed to evaluate the long-term operational potential, and underlying microbial ecology, of this approach for the treatment of a medium-strength (5 g chemical oxygen demand [COD] l(-1)), synthetic, volatile fatty acid-based wastewater. Throughout the trial period of 625 days, extended intervals of consistently stable and efficient wastewater treatment were sustained. These results were highlighted by a short start-up period (21 d), low hydraulic retention times (4.88h), high organic (up to 24.64kg CODm(-3)d(-1)), and volumetric loading rates (up to 4.92 m3 m(-3) d(-1)). A stable, well-settling granular sludge bed was maintained in the bioreactor for the majority of the trial; however, reduced treatment efficiency and biomass washout were observed at an imposed OLR of 36.96 kg COD m(-3) d(-1). The microbial biomass in the bioreactor was investigated using maximum specific methanogenic activity assays and polymerase chain reaction-denaturing gradient gel electrophoresis. A temporal succession of both the bacterial and archaeal populations was noted during the trial, compared to the seed sludge, in response to bioreactor operation at lower temperatures, loading rate increases and to VFA accumulation in the bioreactor. During the trial, an increased contribution of hydrogenotrophic methanogenesis as a pathway of methane production was observed, along with the overall emergence of a highly active psychrotolerent-though still mesophilic biomass.


Subject(s)
Archaea/metabolism , Bacteria/metabolism , Bioreactors , Temperature , Anaerobiosis , Archaea/genetics , Bacteria/genetics , DNA, Bacterial/genetics , Methane/metabolism , Phylogeny , RNA, Bacterial/genetics , RNA, Ribosomal, 16S/genetics , Sewage , Time Factors
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