Perennial forages in rotation with annual crops can improve agricultural resilience by increasing soil organic carbon. However, how nitrogen (N) sources interact with rotation diversity to influence soil nitrous oxide (N2O) emissions is not well understood. During three snow-free seasons, N2O emissions, crop yields, and ancillary variables were measured at three experimental sites with contrasting soil textures (silty clay and sandy loam) in eastern Canada. Using a split-plot design, we compared a corn (Zea mays L.)-soybean (Glycine max [L.] Merr.)-corn rotation and a mixed perennial grass sward receiving N via: i) mineral fertilizer (MIN), ii) liquid dairy manure (LDM), and iii) inclusion of alfalfa (Medicago sativa L.) to the perennial forages with no additional N (LEG). When summed across sites over all three years, cumulative N2O emissions were greater for LDM than MIN in annual crops (8.75 ± 1.63 and 5.15 ± 0.96 kg N2O-N ha–1, respectively), but not in perennial grasses (2.95 ± 0.55 and 3.76 ± 0.70 kg N2O-N ha–1, respectively). When comparing N sources within each crop type over the three years, MIN generated greater yields than LDM in annual and perennial crops, but lower yield-scaled N2O emissions than LDM in annual crops only. During forages post-seeding years, area- and yield-scaled N2O emissions induced by LDM and LEG were lower than MIN. Our results suggest that for a cool humid climate using LDM or LEG in perennial forages and MIN on annual crops can reduce overall N2O emissions, while generating similar or lower yield-scaled emissions.

Although much of the manure in Canada is surface-applied to forages, little research exists evaluating time of year (Time) and rate (Rate) of application on forage yield and nutrient uptake. Field trials (10 yr) on two soils (sandy loam upland and silty clay loam dykeland) investigated this. Experimental arrangement was a factorial [Time (spring, summer, early, and late fall manure applications)] plus a control [spring-applied ammonium nitrate fertilizer (ANF)] in a Latinized split plot. ANF at 0, 25, 50, 100 and 200 kg N·ha−1; 0, 75, 150, and 300 as semi-solid beef (SSM) and 150 kg N·ha−1 as liquid dairy manure (LDM), constituted respective splits. The Time × Rate interaction, later in the trial on the upland soil, showed higher yields and nutrient uptakes with fall manure application. There was little interaction on the dykeland soil; summer application resulted in higher yields at times. For both soils, the optimal long-term application rate of SSM was approximately 150 kg N·ha−1 while that of ANF was approximately 100 kg N·ha−1. Inherent fertility of dykelands resulted in lesser responses to manure addition. Negligible and significant residual N occurred with fertilizer and manure, respectively. Nitrogen, phosphorus, potassium, calcium, magnesium, manganese, copper, zinc, and boron uptakes were due to amendment impact on yield. The recommended rate is 150 kg N·ha−1 of SSM or LDM applied in fall and summer to Maritime grasslands grown on upland and dykeland soils, respectively. Yield differences may not warrant producers adjusting timing of in-season manure application.

Two surface flow constructed wetland systems used to treat agricultural wastewater for over a decade were evaluated for their overall on-going treatment performance and future restoration need. Many on-farm constructed wetlands used for wastewater treatment in Atlantic Canada are now beginning to reach their saturation point and are no longer performing to their full operational potential. This study is an example of the process of evaluating when these systems are no longer viable; or are no longer functioning properly for wastewater treatment and outlines the steps necessary to restore their overall treatment capacities. On-farm constructed wetland restoration has been identified as a best management practice and can be accomplished successfully when important factors such as; landscape, hydrology, function, and the long-term farming goals are considered.

Abstract: Nitrogen (N) losses from agricultural tile drainage systems are environmental and economic losses for producers. This field study quantified N losses from three reps of shallow (SD), deep/conventional (DD), and controlled drainage (CD) on farmland in Nova Scotia. Drainage systems were under corn and alfalfa–oats–clover production. Outflow water and gas samples were obtained and analyzed for nitrate and nitrous oxide. Nitrate-N loads were 5.0, 11.1, and 6.4 kg ha-1 in 2015; 1.8, 6.7, and 2.8 kg ha-1 in 2016; and 0.74, 1.8, and 1.6 kg ha-1 in 2017 for SD, DD, and CD, respectively. Controlled drainage reduced NO3 --N loading by 42.3%–58.2% when compared with the conventional/DD in 2 of 3 yr of study, whereas SD was found to reduce NO3 --N loading by 54.9%–73.1% compared with DD in all years studied. Total NO3 --N losses in this study were measured during the growing season (1 Apr. to 31 Oct.); the magnitude of NO3 --N losses and treatment effects may vary if studied year-round. Nitrous oxide fluxes were variable and low in magnitude throughout the study. Cumulated N2O losses were <1% of the applied N for all drainage types. Controlled drainage increased yields compared with SD and DD. The use of CD in the region could aid in reducing climate stresses, as well as overall NO3 --N loads exiting drainage systems and may enhance crop yields compared with conventional systems. Future studies on dissolved N2O losses from drainage water may provide important insight into whether dissolved N2O losses exceed surface emissions.

The supply of nitrogen to ecosystems has surpassed the Earth's Planetary Boundary and its input to the marine environment has caused estuarine waters to become eutrophic. Excessive supply of nitrogen to salt marshes has been associated with shifts in species' distribution and production, as well as marsh degradation and loss. Our study of salt marshes in agriculturally intensive watersheds shows that coastal eutrophication can have an additional impact. We measured gas fluxes from marsh soils and verified emissions of nitrous oxide (N2O) in nitrogen-loaded marshes while the reference marsh was a sink for this gas. Salt marsh soils are extremely efficient carbon sinks, but emissions of N2O, a greenhouse gas 298 times more potent than CO2, reduces the value of the carbon sink, and in some marshes, may counterbalance any value of stored carbon towards mitigation of climate change. Although more research is merited on the nitrogen transformations and carbon storage in eutrophic marshes, the possibility of significant N2O emissions should be considered when evaluating the market value of carbon in salt marshes subject to high levels of nitrogen loading.

Whereas much scholarship in writing studies has concentrated on what students need to know in a global, media-rich writing environment, this dissertation considers the stakes for teachers, including the nature and kind of expertise that may be necessary to teach effectively and ethically with new digital technologies. An examination of existing instantiations of digital composition instructor expertise shows that the field should embrace a more complex notion of pedagogy that includes the production expertise needed to approach digital texts in a sophisticated way. Currently prevailing models of instructor expertise privilege a pedagogy that remediates print-based standards and rewards traditional discipline-specific analytical skills.By drawing on concepts from expertise theory and elaborating on the rhetorical richness that digital production aptitude provides, this dissertation shows that currently prevailing notions of expertise are too limited to enable the sophisticated analysis and production of digital texts. Developing transformed expansive notions of expertise more responsive to the rich interworkings of pedagogical and professional needs, this dissertation argues, involves embracing a notion of deliberate practice fostered by theorizing and practicing style as a complex adaptive system. Ultimately, developing an effective and ethical pedagogy for digital technologies requires us to question calcified assumptions within digital composition pedagogy and to adopt a stance that allows for mutability and reflective nostalgia (Boym, 2002) instead of fixity.

Given the patrilineal and patriarchal structure of traditional Albanian society, solidarity networks between married Albanian women and their family of origin have until recently been limited. This paper presents data from a multi-sited study of rural Albanian migrants and non-migrants. It shows how the experience of migration has led in some cases to a loosening or renegotiation of male solidarity behaviour towards ageing parents and patrilineal kin (although the expectations of non-migrant patrilineal kin do not seem to be changing with the same rapidity), and also to a widening of transnational and local female solidary behaviour towards their own kin (not always patrilateral). The paper discusses in what cases this solidarity is most commonly produced or expected, what form it takes, and how it is interpreted by actors of local and diaspora society. When the expectations of non-migrant kin are not fulfilled by male migrant/non-migrant kin solidary behaviour, can female kin solidarity 'fill the gap', or is it interpreted as being of another nature?

This chapter is presented in two sections. The first by Bright and Tarrant describes visitor preferences and examines users' perceptions of encountering other visitors in outdoor recreation settings. The second by Tarrant and others reviews visitor preferences for, and satisfactions with, outdoor recreation experiences. Outdoor recreation experiences are investigated by means of an in-depth review of the published literature since 1986, focusing upon (1) measurement and application of the Recreation Experience Preference (REP) scales developed to measure user motives for outdoor recreation involvement, and (2) user attitudes toward social encounter levels. Encounter levels were examined because of the vast amount of literature in the past 10 years devoted to determining recreation use carrying capacities. The second part of the chapter is an analysis and summary of data from the Customer Use and Survey Techniques for Operations, Management, Evaluation, and Research (CUSTOMER) study, which resulted in interviews of over ll,OOO visitors to 31 outdoor recreation sites across the country between 1990 to 1994. Using the framework of importance and performance, this section explores visitor preferences for, and satisfactions with, site attributes for six types of outdoor recreation settings (general, developed, dispersed, water, roaded, and winter).

Four years of performance data from a free-water surface constructed wetland receiving dairy wastewater in Nova Scotia was used to compute first order reaction rate constants (Ka) for several parameters including BOD5, TP, TKN, NH4+-N, FC, and TSS. Flow rates at the inlet and outlet of the 5 m wide × 20 m long wetland were continuously measured to assess how external hydrologic influences affected the water budget of the wetland and the system treatment performance. The Ka values were calculated using inlet and outlet concentrations and an assumption of plug flow hydraulics. Adjusted rate constants (Kac) were also computed, in which the effects of dilution and concentration on pollutant concentrations were considered. Precipitation, runoff, and evapotranspiration had a large influence on the wetland water budget. Values of Ka were higher than Kac for all wastewater parameters, illustrating the effects of dilution on outlet pollutant concentrations and the importance of accurately characterizing wetland hydrology when determining or using rate constants. The Kac values did not appear to be influenced by temperature or solar radiation, but were positively correlated with the hydraulic loading rate for most parameters. Rate constants were lower than those reported in the literature for livestock wastewater treatment wetlands operating in warmer climates. This could be due to differences in climate, but could also be attributed to the relatively high strength wastewater and low hydraulic loading rate (0.1 m month–1) used in this study. Key words: treatment wetlands, cold climate, agricultural wastewater, design, rate constants.

Constructed wetlands are used throughout North America to treat various types of wastewater in warm climates; however, little has been documented about their treatment processes and efficiencies during winter periods in Atlantic Canada. Two small-scale constructed wetlands (100 m2) of differing operational depth (wetland 1: 0.15 m shallow zone depth and wetland 2: managed water level) were designed to treat agricultural wastewater at the Bio-Environmental Engineering Center of the Nova Scotia Agricultural College. Both wetlands were monitored from November 2000 through March 2002 to evaluate treatment efficiencies and mass reductions of five-day biological oxygen demand (BOD5), total suspended solids (TSS), total phosphorus (TP), and ammonia-nitrogen (NH3-N). An average loading rate of 44.7 kg BOD ha−1 d−1 was loaded into each wetland, even during winter months. Percent removal and mass reductions for BOD5, TSS, TP, and NH3-N in both wetlands, irrespective of water levels, ranged from 62 to 99%. The treatment of TP was not found to be as effective as the other parameters, especially during high loading periods. Results show promise for the operation of constructed wetlands on a year-round basis in Atlantic Canada.

In an increasingly global and post-modern world marked by rapid technological, political, and social change, teachers at all levels face the difficult if not impossible challenge of preparing a coming generation for a world that they, themselves, have never seen or experienced (Mead, 1970). Within this context, Donna Haraway’s “Manifesto for Cyborgs” has offered a broad range of humanist teachers and scholars a challenge and the possibility of hope. In part, it is Haraway’s interdisciplinary background in philosophy, biology, and English that has made her work so important to such a wide range of scholars. She earned her Ph.D. in biology from Yale in 1976 and has since helped to articulate and explore the interconnections among language, science, and technology both as a scholar and as a teacher in the History of Consciousness program at the University of California Santa Cruz. Her major works include Crystals, Fabrics and Fields: Metaphors of Organicism in Twentieth-Century Developmental Biology (1976), Primate Visions: Gender, Race, and Nature in the World of Modern Science (1989/1992), Simians, Cyborgs, and Women: The Reinvention of Nature (1991a), and Modest Witness@Second Millennium.FemaleMan©MeetsOncoMouseTM (1997). Haraway’s theory of “situated knowledges” (1991b), however, has also proven instrumental to feminist, post-colonial, and technology studies, emphasizing an approach to scientific inquiry that assigns agency to our “objects of knowledge” and refuses to view them as “a screen or ground or a resource, never finally as slave to the master that closes off the dialectic” (1991b: 198). Her critique of objectivity has extended to Marxist/socialist feminist and cultural theories that provide totalizing or essentializing explanations of self and society. For Haraway, “partiality” as opposed to “universality” (1991b: 195), ambiguity as opposed to certainty, provide more productive ground for both feminist theory and epistemology.

The purpose of this study was to design thermoreversible biomaterials for enhanced adhesion of bone morphogenetic protein-2 (BMP-2)-responsive cells. Peptides containing the arginine–glycine–aspartic acid (RGD) sequence were conjugated to N-isopropylacrylamide (NiPAM) polymers via amine-reactive N-acryloxysuccinimide (NASI) groups. In monolayer cultures, the adhesion of BMP-2-responsive C2C12 cells to RGD-grafted NiPAM/NASI surfaces was significantly higher than adhesion on ungrafted NiPAM/NASI surfaces. Although the morphology of cells adhered to RGD-grafted NiPAM/NASI surfaces was comparable to cells adhered on tissue culture polystyrene (TCPS), long-term cell growth was limited on the NiPAM/NASI surfaces, even for RGD-grafted surfaces. Treatment of C2C12 cells with recombinant BMP-2 induced dose-dependent osteoblastic differentiation as assessed by alkaline phosphatase (ALP) activity. In the absence of BMP-2, cells cultured on NiPAM/NASI polymers (either grafted with RGD peptide or not) expressed significantly higher levels of ALP activity than the cells cultured on TCPS, indicating that the polymer surfaces induced some osteoblastic activity in C2C12 cells without the need for BMP-2. We conclude that NiPAM-based thermoreversible biomaterials, despite their limited ability to support cell growth, allowed an enhanced expression of the chosen osteogenic marker (ALP) by C2C12 cells in vitro.

Smith, E., Gordon, R., Madani, A. and Stratton, G. 2005. Cold climate hydrological flow characteristics of constructed wetlands. Canadian Biosystems Engineering/Le genie des biosystemes au Canada 47: 1.11.7. Hydraulic tracers provide a means of estimating retention times (RTs) of constructed wetlands. The removal of pollutants by these systems is closely associated with their RTs. Better understanding RTs under a range of conditions should therefore help to provide insight into the overall treatment efficiencies offered by on-farm wetlands. The objective of this investigation was to estimate RTs in two similar surface flow agricultural constructed wetlands during high flow periods (i.e. April and January) and compare them to their theoretical retention times (TRT) based on plug flow hydraulics. Two side-by-side wetlands were evaluated and operated at different depths. Both systems were loaded with dairy wastewater at a rate of 50 kg of BOD5 had. Bromide was used as the tracing element and was pulse injected into each wetland. Results demonstrated that RTs were 50 to 60% of the TRT. Bromide appears to be a suitable ionic tracer for non-growing season wetland studies. Mass recoveries of the tracer ranged from 72 to 81%. Only 50 to 65% of the volume in these systems was considered to be active, indicating that there needs to be more uniform mixing. Flow conditions however, appeared to be good in both ice covered and unfrozen conditions.

Thermoreversible polymeric biomaterials are finding increased acceptance in tissue engineering applications. One drawback of the polymers is their synthetic nature, which does not allow direct interaction of mammalian cells with the polymers. This limitation may be alleviated by grafting arginine-glycine-aspartic acid (RGD) containing peptides onto the polymer backbone to facilitate interactions with cell-surface integrins. Toward this goal, N-isopropylacrylamide (NiPAM)-based thermoreversible polymers containing amine-reactive N-acryloxysuccinimide (NASI) groups were synthesized. Conjugation of RGD-containing peptides to polymers was demonstrated with H-1 NMR spectroscopy and reverse-phase high-pressure liquid chromatography. The conjugation reaction was optimal at 4 degreesC and pH of 8.0, and increased with the increasing NASI content of polymers. With a peptide grafting ratio of 0.25 mol %, there was no significant change in the lower critical solution temperature of the polymers. Finally, the NASI-containing polymers, cast as films, on tissue culture polystyrene, were shown to conjugate to RGD-containing peptides and support C2C12 cell attachment. We conclude that NASI-containing thermoreversible polymers are amenable for grafting biomimetic peptides to impart cell adhesiveness to the polymers. (C) 2003 Wiley Periodicals, Inc.

A modified version of the importance-performance (I-P) framework that includes a measure of statistical variance (in addition to mean values) is compared to the traditional I-P model (that includes only mean values). The I-P framework is used to evaluate customer satisfaction with outdoor recreation settings and to identify specific attributes that managers should target their marketing efforts toward. Results are displayed in a four-quadrant grid based on how customers rate the attributes along a scale from low to high importance and low to high performance. The modified I-P approach is demonstrated using different sample sizes (ranging from small to large) and a diverse array of outdoor recreation settings (ranging from the primitive to the developed). Over 11,000 visitors to 31 outdoor recreation sites across the US completed a mail-back survey that measured importance and performance characteristics of multiple setting attributes for one of five specific outdoor recreation settings (developed, dispersed, water, roaded or winter). Results show that the traditional I-P model works well for very large samples (e.g., in excess of 1000 respondents), but not as well for smaller samples (e.g., less than 400). In the modified model, the number of attributes that fell fully within one of the four I-P quadrants varied from an average (across all recreation settings) of 57.9% for large sample sizes to 48.1% for small sample sizes. Only one attribute (hazards) consistently fill within the 'concentrate here' quadrant. Adaptations and considerations of the I-P framework for future research are proposed, along with implications for using the approach in recreation planning models.

The subclass of Near-Contact Binary stars (NCB) was defined by Shaw (1990). They are eclipsing binaries which 1) have periods of less than one day, 2) exhibit strong tidal actions, 3) are less than 0.1 orbital radius apart at their facing surfaces, but they are not in contact. They also have an A- or F- type primary component and a much cooler (by one or two spectral types) secondary, and most have at least one component filling its Roche lobe. There is evidence that they are evolutionary precursors to A-type UMa sources and that they are in the early stages of mass transfer.