Control of macrophytes by grass carp (ctenopharyngodon idella) in a Waikato drain, New Zealand

Hornwort (Ceratophyllum demersum L.) and other aquatic macrophytes have historically been mechanically removed from the Rangiriri drain and Churchill East drain to maintain drain efficiency. As an alternative control method for the high plant biomass that accumulates at the end of summer, the effect of stocking diploid grass carp (Ctenopharyngodon idella L.) on the aquatic vegetation was evaluated in these Waikato drainage systems. At the start of the trial, both drains had a low diversity of aquatic macrophytes, and of the nine species (including the emergents), seven were exotic. Two months after grass carp were released to Churchill East drain (the treated drain) the four submerged and floating macrophyte species became scarce in the main drain. Over the same period, these species increased in biomass in Rangiriri drain (the untreated drain), where hornwort became dense and surface-reaching and remained so for the duration of the trial. However, grass carp did not control submerged vegetation in smaller side drains or the shallow, upper parts of the main drain, or the marginal sprawling species and emergent species. The cost of leasing the grass carp was similar to the cost of clearing the drains mechanically, but grass carp provided continuous weed control. However, subsequent to this trial, 62 dead grass carp were found in Churchill East drain in February 2001, and weed cover subsequently increased. This illustrates that grass carp management in New Zealand agricultural drains can be problematic due to periodic fish kills

Fish and macroinvertebrates in lowland drainage canals with and without grass carp

Diploid grass carp (Ctenopharyngodon idella L.) were introduced to a lowland Waikato drainage canal at an initial density of 40-80 kg ha -1(83-167 fish ha -1) to control aquatic macrophytes and improve water flow. A near-by canal was left without grass carp to act as an untreated control. After 7 months, macrophytes occupied 17% of the water column in the treated canal compared to 78% in the untreated canal. Fish and macroinvertebrates in both canals were examined before and after the release of grass carp by sampling with replacement by fyke netting on seven occasions. Brown bullhead catfish (Ameiurus nebulosus (Lesueur)) and shortfinned eels (Anguilla australis Richardson) comprised most of the resident fish biomass in both canals; however, before grass carp stocking, eels were more abundant than catfish in the treated canal. There was no change in the abundance of resident fish after stocking, but young-of-the-year catfish had greater mortality and grew faster in the treated canal than in the untreated canal. Macroinvertebrates were primarily associated with aquatic macrophytes. Grass carp reduced aquatic macrophyte abundance in the treated canal by about 80%, which by inference reduced the abundance of associated macroinvertebrates, but there was no observed impact of grass carp stocking on the resident fish assemblage. We examined the relationship between head width and fish length, and from this determined that 70% of the grass carp could have escaped through the downstream retention screen. Despite this possibility, grass carp remained in the canal and effectively controlled aquatic macrophytes for 18 months

Predicting employees' commitment to and support for organisational change

This study aimed to identify factors that predict employees' commitment to and support for organisational change. The three components of Herscovitch and Meyer's (2002) commitment to organisational change model were hypothesised to mediate the relationship between organisational climate and behavioural support for organisational change. Data were collected from a Queensland government department (N = 342). Analysis of correlations revealed that organisational climate, commitment to change, and behavioural support for change variables were all significantly related. Structural equation modelling demonstrated that affective, normative, and continuance commitment to change were all predictors of behavioural support for organisational change. Positive work climate also contributed directly to the prediction of behavioural support for change over and above the indirect influence through commitment to organisational change, indicating a partial mediation effect. These findings support Herscovitch and Meyer's (2002) three-component model of commitment to organisational change and extend their nomological network by showing the relevance of two types of organisational climate to the core components of the model. Affective commitment to organisational change is a positive influence on employees' behavioural support for change and also reflects healthy aspects of the organisational climate. However, continuance commitment to organisational change is detrimental influence on employees' behavioural support for change and is linked with unhealthy dimensions of the organisational climate

Community Technology? Issues in Computer-Supported Work

In this paper I wish to discuss a number of issues concerning work practices, especially communication and cooperation among people, and examine how we can use the computer as a tool and/or medium for supporting such group activities. The intent is not to substitute computer-mediated for face to-face or other forms of communication, but rather to discover if there are additional possibilities that may be afforded us through use of computing technology. My emphasis is not with the technology per se, but with people, their needs and activities. My focus is on how we can augment human capabilities through use of the technology, rather than on how to simulate or replace labour processes with machines. I believe, along with Rosenbrock and many others, that our present-day utilization of information technology in work has tended to restrict, rather than expand human potential. This is not due solely to the nature of the technology itself, although it is not a neutral element, but also to the organization of work around the technology, and the general socio-economic and political rationale within our society which develops these machines and industrial systems. The paper does not present a carefully compiled rationale for an alternative technology, or an argument for the construction of new ''widgets'', but consists of a number of observations, reviews of rcsearch, experiences with current technologies, and speculations about possible future uses of technology in promoting communication between people. The intent is to sharpen our understanding of everyday activities, and open up alternative paths for future design of support technology. Reaction in the form of supportive or negative examples of technology use in group settings is particularly welcome from readers

Alien Registration- Bannon, William J. (Bar Harbor, Hancock County)

https://digitalmaine.com/alien_docs/19926/thumbnail.jp

Discovering the Human Actors in Human Factors

This essay discusses some problems and prospects for the field of human factors or ergonomics, specifically the more recent, and diversified field of human-computer interaction. Its main aim is to develop awareness of how an often unarticulated, though dominant perspective in the field can blind us to other more fruitful conceptions of human-computer interactions, and to emphasize the importance of shifting perspectives in the design process

Improving child protection : a systematic review of training and procedural interventions

Aim: To synthesise published evidence regarding the effectiveness of training and procedural interventions aimed at improving the identification and management of child abuse and neglect by health professionals. Methods: Systematic review for the period 1994 to 2005 of studies that evaluated child protection training and procedural interventions. Main outcome measures were learning achievement, attitudinal change, and clinical behaviour. Results: Seven papers that examined the effectiveness of procedural interventions and 15 papers that evaluated training programmes met the inclusion criteria. Critical appraisal showed that evaluation of interventions was on the whole poor. It was found that certain procedural interventions (such as the use of checklists and structured forms) can result in improved recording of important clinical information and may also alert clinical staff to the possibility of abuse. While a variety of innovative training programmes were identified, there was an absence of rigorous evaluation of their impact. However a small number of onegroup pre- and post-studies suggest improvements in a range of attitudes necessary for successful engagement in the child protection process. Conclusion: Current evidence supports the use of procedural changes that improve the documentation of suspected child maltreatment and that enhance professional awareness. The lack of an evidence based approach to the implementation of child protection training may restrict the ability of all health professionals to fulfil their role in the child protection process. Formal evaluation of a variety of models for the delivery of this training is urgently needed with subsequent dissemination of results that highlight those found to be most effective

CSCW - Four Characters in Search of a Context

The title of this paper was chosen to highlight the fact that the label CSCW, although widely adopted as the acronym for the field of Computer Supported Cooperative Work, has been applied to computer applications of very different ilk. It is not at all clear what are the unique identifying elements of this research area. This paper provides a framework for approaching the issue of cooperative work and its possible computer support. The core issues are identified and prospects for the field are outlined