Some Results On Normal Homogeneous Ideals

In this article we investigate when a homogeneous ideal in a graded ring is normal, that is, when all positive powers of the ideal are integrally closed. We are particularly interested in homogeneous ideals in an N-graded ring generated by all homogeneous elements of degree at least m and monomial ideals in a polynomial ring over a field. For ideals of the first trype we generalize a recent result of S. Faridi. We prove that a monomial ideal in a polynomial ring in n indeterminates over a field is normal if and only if the first n-1 positive powers of the ideal are integrally closed. We then specialize to the case of ideals obtained by taking integral closures of m-primary ideals generated by powers of the variables. We obtain classes of normal monomial ideals and arithmetic critera for deciding when the monomial ideal is not normal.Comment: 19 page

How can technology make this work? Preservice teachers, off-campus learning and digital portfolios

Utilising appropriate Information Communication Technologies (ICT) as instructional tools in teacher education can be a challenging yet worthwhile endeavour. This paper reports the difficulties and benefits of a recent inter-university project requiring preservice primary teachers to construct professional digital portfolios using the support of ICT. Challenges with regard to communication and learning were numerous as 34 preservice teachers (PSTs) from three universities in NSW (situated in country towns, and in Sydney) worked together as a collaborative learning community. Meeting regularly face-to-face during the 12-month process was not always possible and so ICT resources were employed to facilitate instruction and communication. An action research methodology generated a data set of surveys, observational field notes, and student assessment artefacts. We share the findings in this paper so that others may learn from our experiences in using free access software and commonplace hardware when constructing digital portfolios with students who are some distance from campus

Opportunities for Public Aquariums to Increase the Sustainability of the Aquatic Animal Trade

The global aquatic pet trade encompasses a wide diversity of freshwater and marine organisms. While relying on a continual supply of healthy, vibrant aquatic animals, few sustainability initiatives exist within this sector. Public aquariums overlap this industry by acquiring many of the same species through the same sources. End users are also similar, as many aquarium visitors are home aquarists. Here we posit that this overlap with the pet trade gives aquariums significant opportunity to increase the sustainability of the trade in aquarium fishes and invertebrates. Improving the sustainability ethos and practices of the aquatic pet trade can carry a conservation benefit in terms of less waste, and protection of intact functioning ecosystems, at the same time as maintaining its economic and educational benefits and impacts. The relationship would also move forward the goal of public aquariums to advance aquatic conservation in a broad sense. For example, many public aquariums in North America have been instrumental in working with the seafood industry to enact positive change toward increased sustainability. The actions include being good consumers themselves, providing technical knowledge, and providing educational and outreach opportunities. These same opportunities exist for public aquariums to partner with the ornamental fish trade, which will serve to improve business, create new, more ethical and more dependable sources of aquatic animals for public aquariums, and perhaps most important, possibly transform the home aquarium industry from a threat, into a positive force for aquatic conservation. Zoo Biol. 32:1-12, 2013. © 2012 Wiley Periodicals, Inc

Process eco-innovation: assessing meso-level eco-efficiency in industrial water-service systems

Eco-innovation combines economic advantage with lower ecological-resource burdens. Eco-innovation has been generally directed at energy input-substitutes, component recycling, etc. Some companies have made investments reducing resource burdens in the production process. This study investigated options for eco-efficiency improvement in two large manufacturing companies, Volvo and Arla Foods. Their impetus for eco-innovation comes from the companies' environmental policies, as well as from external drivers such as future higher costs and resource scarcity. Relative to their respective industrial sector, these companies represent strong prospects for reducing resource burdens in water-service processes, especially from chemical inputs and wastewater. Such eco-innovations involve more complex interactions beyond the production site, so the options warrant a whole-system comparative assessment. The EcoWater project has analysed the entire water-service value chain through meso-level interactions among heterogeneous actors (process-water users, providers and wastewater treatment companies). The project has developed a methodology to obtain the necessary information, to involve stakeholders in the assessment and to facilitate their discussion on alternative options. Each study stimulated internal company discussions on the need and means to evaluate whole-system effects of investment decisions. Inter-organisational cooperation helped to anticipate how meso-level resource efficiency relates to lower burdens in wastewater treatment. The assessment method can be extended to any water-service system. By comparing options, the method can facilitate better decisions improving meso-level resource efficiency. As wider implications, some improvement options may complicate ‘eco-innovation’ as double-eco benefits: win-win for whom, where and what level

Biological flora of Central europe: Baldellia ranunculoides (Alismataceae)

Baldellia ranunculoides (L.) Parl. (Alismataceae) is a taxonomically problematic aquatic plant with an historically ill-defined distribution and global conservation status. This paper finds morphological, ecological and molecular evidence for two distinct taxa, probably best described as subspecies: (1) B. ranunculoides subsp. ranunculoides and (2) B. ranunculoides subsp. repens and provides detailed distribution data on their overlapping range, in different habitats, across the cool, high rainfall areas of western Europe and west Mediterranean. The two subspecies are amongst the relatively large number of threatened European and north Africa aquatic plants and this paper provides a systematic review of their relative conservation pressures and management needs, with particular emphasis on the status of both taxa in central Europe. Other observations indicate probable evolutionary relationships within B. ranunculoides s.l. and its associated taxa and the review points out where these and other research topics could potentially be pursued

Importance of geographic origin for invasion success: A case study of the North and Baltic Seas versus the Great Lakes-St. Lawrence River region

Recently, several studies indicated that species from the Ponto-Caspian region may be evolutionarily predisposed to become nonindigenous species (NIS); however, origin of NIS established in different regions has rarely been compared to confirm these statements. More importantly, if species from certain area/s are proven to be better colonizers, management strategies to control transport vectors coming from those areas must be more stringent, as prevention of new introductions is a cheaper and more effective strategy than eradication or control of established NIS populations. To determine whether species evolved in certain areas have inherent advantages over other species in colonizing new habitats, we explored NIS established in the North and Baltic Seas and Great Lakes–St. Lawrence River regions—two areas intensively studied in concern to NIS, highly invaded by Ponto-Caspian species and with different salinity patterns (marine vs. freshwater). We compared observed numbers of NIS in these two regions to expected numbers of NIS from major donor regions. The expected numbers were calculated based on the available species pool from donor regions, frequency of shipping transit, and an environmental match between donor and recipient regions. A total of 281 NIS established in the North and Baltic Seas and 188 in the Great Lakes–St. Lawrence River. Ponto-Caspian taxa colonized both types of habitats, saltwater areas of the North and Baltic Seas and freshwater of the Great Lakes–St. Lawrence River, in much higher numbers than expected. Propagule pressure (i.e., number of introduced individuals or introduction effort) is of great importance for establishment success of NIS; however in our study, either shipping vector or environmental match between regions did not clarify the high numbers of Ponto-Caspian taxa in our study areas. Although we cannot exclude the influence of other transport vectors, our findings suggest that the origin of the species plays an important role for the predisposition of successful invaders