Water Retention, Bulk Density, Particle Size, and Thermal and Hydraulic Conductivity of Arable Soils in Interior Alaska

The relative proportion of liquid, gas, and solid as constituents of soil depends on factors such as climate, biological activity, and management practices. Therefore, the physical state of soil is a dynamic process, changing with time and position in the profile. Temperature, thermal and hydraulic conductivity, density, and water content are some quantitative properties characterizing the physical state of soil. These properties are important in describing soil processes such as water and heat flow, movement of chemicals, biological activity, and erosion. Water in the soil is subject to a number of forces resulting from the attraction of the soil matrix for water and presence of solutes and gravity. The energy status of water-the sum of these forces-is termed water potential. Processes such as evaporation and plant water uptake are governed by the gradient in water potential in the soil and across the root-soil interface, respectively. The term water potential is more descriptive of the soil water status than water content as movement of water is in response to differences in water potential

Migration of Water During Winter in West Central Minnesota Soils

Soil freezing influences the amount and quality of our water resources, yet, little is known concerning the impacts of soil texture and water content before freezing on water migration in frozen soils. Columns of Hamerly clay loam and Sioux loam at 3 initial water contents were subjected to the vagaries of the field environment at Morris, Minnesota during the winter of 1993-1994 and then sectioned to determine changes in soil water content. Redistribution of water in the frozen soil layer became more apparent with an increase in initial water content. Little movement of water occurred at the lowest initial water content of 0.21 g g-1 (45% pore saturation). Soil water redistribution was more pronounced for the. Sioux loam, but only at the highest initial water content of 0.38 g g-1 (8QO;O pore saturation). Upward water movement appeared greatest when the rate of descent of the freezing front was slowest. Initial water content had a larger effect on water movement in frozen soil profiles than soil texture. Therefore, soil water content at the time of freeze-up in the fall will determine, to a large extent, the rate of water (and consequently solute) movement in soil profiles during winter

Dissipation of Bromide and Metribuzin Affected by Tillage and Crop Residue Management in Subarctic Alaska

Prudent use of agricultural fertilizers and herbicides is paramount for sustaining or improving surface and ground water quality in Subarctic regions, but little information is available that documents the loss of chemicals from agricultural lands in the Subarctic. This study aimed to ascertain more clearly how time of application and land management practices affect the loss of bromide and metribuzin in a Subarctic soil. Potassium bromide (KBr), a surrogate for nitrate, and metribuzin, commonly used to control broadleaf weeds, were applied in the autumn of 1996 and the spring of 1997 to a silt loam that had been subjected to conventional tillage (CT), minimum tillage (disk once [DO]), and no tillage (NT) since 1983. Superimposed on the tillage treatments were the removal or retention of barley (Hordeum vulgare L.) stubble and loose straw. Loss of these chemicals was ascertained by sampling the soil profile at the time of heading of barley, before freeze-up of the soil in autumn, and after spring thaw until September 1998. Tillage and residue treatments did not influence the recovery of autumn-applied or spring-applied Br. However, recovery of Br diminished with time: about 30% of the Br applied in autumn and 45% of that applied in spring remained in the soil profile by September 1998. Tillage, but not residue, treatments influenced the recovery of metribuzin. Recovery of metribuzin at the termination of this study was 6% or more in NT soil and 2% or less in CT and DO soil; greater recovery in NT soil was presumably a result of slower degradation in NT than in CT and DO. This study suggests that bromide (and thus nitrate) and metribuzin are more prone to leaching when applied in autumn and that tillage practices affect retention of metribuzin, but not nitrate, in the soil of Subarctic Alaska.Une utilisation prudente des engrais et des herbicides est cruciale au maintien ou à l’amélioration de la qualité de l’eau de surface et de l’eau souterraine dans les régions subarctiques, mais il existe peu de documentation sur la déperdition des produits chimiques dans le sol des terres agricoles du Subarctique. Cette étude vise à établir avec plus de précision la façon dont le moment de l’application et les pratiques de gestion des terres affectent la déperdition du bromure et de la métribuzine dans un sol subarctique. Le bromure de potassium (KBr), un substitut du nitrate, et la métribuzine, couramment utilisée pour lutter contre les dicotylédones, ont été appliqués en automne 1996 et au printemps 1997 sur un loam limoneux qui avait subi un travail du sol classique (TC), un travail minimum (un seul passage du cultivateur à disque [TM]) et aucun travail (AT) depuis 1983. On a ajouté au travail du sol le déchaumage de l’orge (Hordeum vulgare L.) ou le maintien du chaume et de la paille. On a vérifié la déperdition de ces produits chimiques jusqu’en septembre 1998 en analysant le profil pédologique au moment de l’épiaison de l’orge, avant que le sol gèle à l’automne et après le dégel printanier. Le travail du sol et le traitement des résidus n’ont pas influencé la récupération du Br appliqué en automne ou au printemps. La récupération du Br a cependant diminué avec le temps: en septembre 1998, environ 30 % du Br appliqué à l’automne et 45 % de celui appliqué au printemps persistaient dans le profil pédologique. Le travail du sol, mais pas le traitement des résidus, influençait la récupération de la métribuzine. À la fin de l’étude, la récupération de la métribuzine était de 6 % ou plus dans le sol AT, et de 2 % ou moins dans les sols TC et TM; une récupération plus importante dans le sol AT résultait probablement d’une dégradation plus lente dans le AT que dans le TC et le TM. Cette étude suggère que le bromure (et, par conséquent, le nitrate) et la métribuzine sont plus sujets au lessivage quand ils sont appliqués en automne, et que les pratiques de travail du sol affectent la rétention de la métribuzine, mais pas celle du nitrate, dans le sol de l’Alaska subarctique

Exploring the challenges and potentialities of the database of religious history for cognitive historiography

This article explores the potential impact and contribution of the Database of Religious History (DRH) project within the field of Cognitive Historiography. The DRH aims to bring together, in a systematic and open-access format, data on religious groups from across the globe and throughout history. By utilizing robust, open-source technologies and best-practice software principles, the DRH constitutes a novel and innovative approach to historical and cultural studies. As a contribution to the scientific study of both religion and history, the DRH offers data amenable to statistical analyses, thus providing tools for assessing diachronic cultural innovation and adaptation, the testing of grand narrative theories of religious change, and for enriching and revitalizing traditional fields such as comparative religions, history of religion(s), and anthropology of religion. In this article we explore the methods employed in collecting and digitizing historical data, identify our unit of analysis, outline the challenges of recruiting historians of various fields, and highlight the DRH’s methodological potential for both Religious Studies and Cognitive Historiography

The Treatment of Nature in the Poetry of Coleridge

The treatment of nature by the English Romantic poets of the nineteenth century is commonly thought to be confined to the poetry of Wordsworth. Although the bulk of Wordsworth\u27s poetry is concerned with nature, a study of the poetry of the period reveals that the other great Romanticists were also interested in nature. This thesis is written to show how great a factor the treatment of nature is in the poetry of Samuel Taylor Coleridge

Termite resistance of DMDHEU-treated wood.

Four field trials were conducted with wood modified with dimethyloldihydroxy-ethyleneurea (DMDHEU) in contact with subterranean termites. Trials 1 to 3 were conducted with Coptotermes acinaciformis (Froggatt); 1 and 2 in south-east Queensland, and 3 in northern Queensland, Australia. Trial 4 was conducted in northern Queensland with Mastotermes darwiniensis (Froggatt). Four timber species (Scots pine, beech, Slash pine and Spotted gum) and two levels (1.3 M and 2.3 M) of DMDHEU were used. The tests were validated. DMDHEU successfully prevented damage by C. acinaciformis in south-east Queensland, but not in northern Queensland. It also did not protect the wood against M. darwiniensis. Except for beech in trial 4, DMDHEU led to reduced mass losses caused by termite attack compared to the unmodified feeder stakes. Slash pine (in trials 1 and 3) and Spotted gum (in trial 1) presented low mass losses. Modification of Scots pine was more effective against termite damage than the modification of beech

Are foot and ankle characteristics associated with falls in people with rheumatoid arthritis? A prospective study.

OBJECTIVE: To determine whether foot and ankle characteristics are associated with falls in people with rheumatoid arthritis (RA). METHODS: Two hundred and one adults with RA were recruited from rheumatology outpatient clinics in Auckland, New Zealand. Clinical characteristics, common fall risk factors, and foot and ankle variables were measured. Participants were prospectively studied for 12 months, to record the occurrence of falls using falls diaries. Logistic regression analysis identified baseline variables which were independent predictors of falls over the 12 months. RESULTS: Eighty-four (42%) participants fell at least once and 39 (19%) experienced multiple (>1) falls over the 12-month follow-up period. In logistic regression analysis, including age and significant baseline variables in bivariate analysis but not baseline fall history, presence of foot or ankle tender joints (odds ratio (OR) 1.95, P=0.034) and psychotropic medication (OR 2.35, P=0.025) were independent predictors of prospective falls. However, when baseline fall history was included in the analysis, psychotropic medication (OR 2.34, P=0.025) and baseline fall history (over the preceding 12 months) (OR 2.27, P=0.008) were independent predictors of prospective falls. CONCLUSION: Foot and ankle characteristics are not associated with falls in people with RA, independent of prior falls. Enquiry about prior falls and psychotropic medications may assist in identifying patients with RA who are at high risk of future falls. This article is protected by copyright. All rights reserved

Analysis of iteration schemes for deterministic transport in binary Markovian mixtures

The Adams-Larsen-Pomraning coupled transport model has been used to describe neutral particle transport in binary stochastic mixtures. Here, the mixing statistics are considered to be homogeneous Markovian processes. While the model is robust, the convergence behavior and efficiency of this coupled model have not been addressed. Countless iterative methods could be employed to solve the coupled model. In this study, three candidate iterative schemes are analyzed with the Fourier analysis technique. The schemes are tested and implemented with a variety of material data to observe the convergence behaviors. While two schemes appear to be stable and convergent, both can converge slowly in the presence of scattering. We develop a two-grid acceleration scheme to improve the convergence rate of the fully-implicit iteration scheme. A shape function from the high-order coupled transport equations (fine-grid) is used to collapse cross-sections for an effectively-mixed one-material transport approximation (coarse-grid). In turn, diffusion synthetic acceleration is applied to the coarse-grid transport operator in the event that the effective scattering ratio is near unity. Theoretical and computational results indicate that this two-grid acceleration technique is highly efficient and effective for improving the convergence rate

PPE – Can you have too much of a good thing?

PresentationSpecifying Personal Protective Equipment (PPE) after a hazard has been identified is a critical aspect of a facility’s ability to protect their workers. In a chemical manufacturing facility, manual operations and maintenance activities have the potential to expose workers to hazardous chemicals and flammable atmospheres. Even though it is generally recognized to be one of the least effective safeguards in the hierarchy of controls, PPE is often the last line of defense, and sometimes the only feasible defense, that isolates workers from potential hazards. As a result, companies may lean toward putting workers in higher levels of PPE to provide additional protection. However, in many cases higher levels of PPE may introduce new hazards associated with limited worker mobility, fatigue, unreliable job performance, or limited egress. Therefore, PPE specification should focus not only on what is necessary to protect the worker, but also what is appropriate for a given job task. In this paper, a risk-based approach to PPE selection, specification, and use will be presented. Discussion will focus on potential hazards that can be inadvertently introduced because of PPE over-specification. Studies related to the impact of PPE on worker performance will be presented to help demonstrate the potential negative impacts of over specifying PPE. Lastly, a case study will be presented where a PPE specification was questioned, and the impact of increasing the PPE specification for a job task was evaluated

Frozen Soils: A Perspective On Past And Future Research For Promoting Sustainable Agricultural Systems

Frozen soils impact many industries which rely· on soil, water, and .air resources in developing and manufacturing products. Most noteworthy is the agricultural industry in the northern United States where soils, which sustain food and fiber production, are subjected to frequent freezing and thawing. Soil freezing and thawing influences soil erodibility, surface and ground water quality, air quality, and biological activity. Many strides toward understanding frozen soil processes and managing lands to minimize the adverse effects of freezing and thawing have been made over the last two decades. Yet, further efforts to identify frozen soil processes which influence wind and water erosion, soil faunal adaptation, soil quality, movement of agricultural chemicals,· and rural and urban water supplies will aid industry and society in meeting future needs for food and water