bluuebunny/crossref_metadata_2025 huggingface dataset:
SOIL MANAGEMENT AND VEGETATION EFFECTS ON MEASURED AND ESTIMATED SOIL THERMAL REGIMES IN CANADA
Authors: HAYHOE H. N. , TARNOCAI C. , DWYER L. M.
Published: March 2010

Observations at sites in British Columbia, the Yukon, Manitoba and Nova Scotia over a range of soils, managements and vegetation were used to assess variation in soil temperature. The annual soil temperature regime was compared with estimates derived from a macroclimate model which was developed for mineral soils that are level, well to moderately well drained, and covered by short grass. In general, this study showed the dampening effect of vegetation cover on soil temperature and suggested the further dampening effect of an organic layer on the soil surface. However, soil temperatures for cultivated and grass sites were not significantly different (P ≥ 0.05) from the estimates made using the macroclimate model. In contrast, forested sites had significantly (P ≤ 0.05) colder soil temperatures than those estimated by the model. The mean annual and mean summer 0.50 m soil temperatures were, respectively, 1.3 and 3.2 °C colder than the corresponding estimates. Key words: Soil thermal regimes, estimation of soil temperature, mean annual soil temperature
COMPARISON OF NITROGEN MINERALIZATION IN FOREST FLOOR MATERIALS USING AEROBIC AND ANAEROBIC INCUBATION AND BIOASSAY TECHNIQUES
Authors: FYLES J. W. , FYLES I. H. , FELLER M. C.
Published: March 2010

Nitrogen mineralization in five forest floors of differing morphological characteristics was compared using a greenhouse plant bioassay and laboratory aerobic and anaerobic incubations. Forest floors dominated by F materials mineralized more N and had higher k values than those dominated by H. Plant N uptake in the bioassay was highly correlated with N mineralized during the laboratory incubations across all forest floors but was 50–80% lower than predictions based on first-order kinetic parameters derived from the aerobic incubation. The relationship between bioassay plant uptake and predicted N mineralization differed among forest floors, indicating that the effect of plants on dynamics of the mineralizable N pool differs among organic matter types. Differences in N mineralization characteristics between forest floor materials suggest that forest floor morphology may provide a basis for assessing site quality. Key words: Nitrogen, anaerobic mineralization, aerobic mineralization, bioassay, forest floor
THE CHARACTERIZATION OF SOIL MACROPOROSITY OF A CLAY SOIL UNDER TEN GRASSES USING IMAGE ANALYSIS
Authors: GREVERS M. C. J. , JONG E. DE
Published: March 2010

The structure of a clay soil was characterized following the growing of 10 grasses continuously for 11 yr. There were no significant differences in bulk density, total porosity, and air-filled porosity amongst the grass plots. Differences in soil aggregate size were limited to a group of five grasses, where Russian wild ryegrass resulted in larger aggregates in the 0- to 15-cm depth than smooth bromegrass, meadow bromegrass, crested wheatgrass (Fairway) and slender wheatgrass. There were significant differences in soil air-permeability in the 0- to 15-cm depth among all 10 grasses, which were confirmed by differences in the porosity of planar macropores as were measured with image analysis using difference imagery of stereo photographs. The aboveground yield of grass over a 9-yr period was related to the area and length of the macropores, of the planar macropores, and of the intermediate macropores. The greater the yield of the grasses, and therefore the greater the amount of soil-water depletion by grass roots, the greater the resulting area and length of the different kinds of macropores. Differences in yield explained up to 50% of the variation in the macropores in the 0- to 30-cm depth, and up to 35% of the variation in the macropores in the 30- to 60-cm depth. Analysis of the root systems of the grasses by image analysis revealed significant differences in the top 45 cm of the soil profile. However, there were no apparent relationships between the characteristics of the root systems of the grasses and the resulting characteristics of the soil macropores, or in the pattern of soil-water depletion with respect to depth amongst the grass plots. The majority of grasses depleted moisture mainly from the top 70 cm of soil. Key words: Grass species, soil structure, image analysis, difference imagery, soil macroporosity, planar voids, water uptake
A TENSION APPARATUS FOR MONITORING WEIGHT LOSS FROM A SINGLE CORE
Authors: RODD A. V. , WEBSTER D. H.
Published: March 2010

A top loading balance can be used to monitor and record drainage from a soil core. Possible applications of the apparatus are discussed. Key words: Tension apparatus, real-time weight loss, soil core
SOIL TEMPERATURE UNDER CONVENTIONAL AND MINIMUM TILLAGE: SIMULATION AND EXPERIMENTAL VERIFICATION
Authors: GRANT R. F. , IZAURRALDE R. C. , CHANASYK D. S.
Published: March 2010

Residue management may affect soil temperature, and consequently soil biological processes, by influencing energy exchange fluxes at the soil surface. Simulation models in which these fluxes are estimated allow the investigation of hypotheses concerning the effect of residue management on soil thermal regimes. The simulation technique used here involves a finite difference approximation to the estimation of hourly water and heat fluxes through a one-dimensional, layered soil medium, with boundary conditions determined at the surface from surface energy exchange processes, and below the profile from source/sink dynamics. Crop and residue cover are considered as they influence radiative fluxes at the soil surface. Estimated soil temperatures were compared to recorded soil temperatures at 0.05- and 0.15-m depths in plots of barley grown under conventional (CT) and minimum (MT) tillage which left 90% and 30% of the soil surface exposed, respectively. Although diurnal trends in soil temperature were consistent with those recorded, the amplitude of diurnal variation was overstimated by the model under CT, and underestimated under MT. Standard differences between recorded and estimated hourly-averaged temperatures were about 2.5 °C at 0.05 m, and half as much at 0.15 m. The model failed to simulate the consistently lower soil temperatures recorded under MT during the early part of the growing season that may have been caused by longer term tillage effects, such as the persistence of ice lower in the soil profile. Examination of early season temperature effects will require longer term simulations in which the hydrologic and thermal implications of snow and ice are considered. Key words: Soil water flux, soil heat flux, surface energy exchange, soil temperature
STUDIES ON THE ADSORPTION OF BORON ON HUMIC ACIDS
Authors: GU BAOHUA , LOWE L. E.
Published: March 2010

The adsorption of B, in the form of boric acid, was studied on three precipitated humic acids (HA), representing three distinct soil types. B adsorption by HA was strongly pH-dependent, being low and relatively constant in the pH range 3.0–6.5, increasing markedly up to a peak at near pH 9.5, and then decreasing at still higher pH values. Adsorption isotherms for pH values near 6.7 and 8.8 conformed well to the Langmuir equation. The adsorption maxima (b values), as calculated with the Langmuir equation, ranged from 73 to 207 mmol kg−1 HA at a pH near 8.8, and from 10 to 42 mmol kg−1 at a pH near 6.7. The considerable variation in B adsorption by these HA samples was attributed to "Fe + Al" contents present as contaminants in the HA. The role of HA in B adsorption is expected to be minor in most acid and near neutral soils, but may be of greater significance in soils of high pH and above average organic matter content. Key words: Boron adsorption, boric acid, humic acid, Langmuir adsorption isotherm.
RATES OF SOIL REDISTRIBUTION ASSOCIATED WITH SOIL ZONES AND SLOPE CLASSES IN SOUTHERN SASKATCHEWAN
Authors: PENNOCK D. J. , JONG E. de
Published: March 2010

The usefulness of the average slope measurements available from soil surveys in the development of regional erosional inventories depends on the relationship between the average slope measurements of the mapped area and the mean rates of soil redistribution within the areas. Using 137Cs redistribution techniques we examined the relationship between mean rates of soil redistribution and average slope characteristics at 21 areas in the Brown, Dark Brown, and Black Chernozem soil zones of southern Saskatchewan. Net soil losses averaged 5.8 t ha−1 yr−1 for areas with mean gradients between 0 and 1.5°, 7.8 t ha−1 yr−1 for areas with mean gradients between 1.0 and 3°, and 11.3 t ha−1 yr−1 for areas with mean gradients between 3.5 and 8.5°. For all three slope classes, the highest rates of soil loss were found in the Dark Brown soil zone and the lowest rates in the Black soil zone. Net soil loss alone was, however, an inadequate indicator of the rate of loss within the areas because a considerable proportion of eroded soil was deposited within the confines of the study areas. Our results indicate that a distinct rate of soil loss was associated with the average slope characteriestics of the study area, but that both net soil loss from the field and mean soil loss within the field need to be considered together if a complete erosional assessment is to be made of an area. Key words: Soil erosion, soil deposition, 137Cs redistribution, slope gradient, Saskatchewan
DISTRIBUTION OF ZINC FRACTIONS IN PRAIRIE SOILS
Authors: LIANG J. , STEWART J. W. B. , KARAMANOS R. E.
Published: March 2010

The distribution of Zn in soil fractions was determined for 27 representative prairie soils from Saskatchewan. Total Zn in the 27 soils under study ranged from 19.0 to 106.6 μg g−1 with an average of 62.0 μg g−1. A sequential fractionation showed that 0.2–2.4% of total Zn was exchangeable, 0.4–8.1% was Pb-displaceable, 0.4–4.3% was acid soluble, 1.6–9.7% was associated with Mn oxides, 0.6–4.4% was associated with organic matter and 0.9–5.1% was associated with Fe + Al oxides. Most of the total Zn was present in residual form (66.9–91.0%). Amounts of Zn in exchangeable and Pb-displaceable fractions varied inversely with soil pH and extractable P. DTPA-extractable Zn was correlated with Zn in most of the fractions, except Fe oxide-Zn, residual-Zn and total Zn. This result indicates that DTPA extractable-Zn contains Zn from Mn oxides and organic matter associations in addition to the exchangeable and adsorbed forms. The amount of total Zn was correlated with clay content and cation exchange capacity thus reflecting differences in parent materials. Key words: Soil Zn, Zn fractions, Prairie soils, pH, clay content
EFFECT OF ROOT EXUDATES FROM CORN AND BROMEGRASS ON SOIL STRUCTURAL STABILITY
Authors: POJASOK T. , KAY B. D.
Published: March 2010

The effect of root exudates on structural stability and the hypothesis that the growing roots of corn (Zea mays L.) can destabilize soil structure by chelating Fe and Al involved in mineral-metal-organic matter linkages were investigated. Exudates were removed from 14C-labelled corn and bromegrass (Bromus inermis Leyss.) plants grown in sand using sequential leaching with water and acetone. The exudates were concentrated by flash evaporation and incubated with 1–2 mm aggregates of a calcareous silt loam soil for up to 240 h. Aggregates to which exudates from bromegrass were added had a higher wet aggregate stability (WAS) and lower dispersible clay content (DC) than aggregates to which exudates from corn were added. The greatest increase in stability occurred on addition of the water-extracted exudates (9.6% for WAS, 27.1% for DC). The increase in stability correlated positively with a release into solution of Ca and Mg from the soil solids. Addition of CaCl2 to the aggregates, to give corresponding amounts of Ca and Mg in solution, had similar effects on stability suggesting that the ions released by the exudates were not in a chelated form. The quantity of carbon added in the exudates and the mineralization of this carbon were positively and negatively correlated with stability, respectively. There was little evidence that corn exudates caused a destabilization of structure. Key words: Wet aggregate stability, dispersible clay, corn, bromegrass, flocculation, calcium
EFFECT OF pH ON PLANT UPTAKE AND SOIL ADSORPTION OF 14C-FLURIDONE
Authors: MALIK N. , DRENNAN D. S. H.
Published: March 2010

Experiments were conducted to obtain a better understanding of the role of pH on the availability of fluridone (1-methyl-3-phenyl-5-[3-(trifluoromethyl) phenyl]-4(1 H)-pyridinone) in soil solution when used as a selective herbicide and the partitioning into aqueous and sediment phases when employed for aquatic plant control. Phytotoxicity of fluridone to seedling sorghum (Sorghum bicolor L.) plants increased with increasing pH of the sand-nutrient solution medium. Since stability and plant uptake of fluridone by bioassay plants were not affected by solution pH, the increasing phytotoxicity at basic pH was attributed to less adsorption and hence higher availability of the herbicide in solution. Soil adsorption studies with 14C-fluridone confirmed this trend, as the soil solution concentration at equilibrium increased from 0.091 to 0.258 μg mL−1 and from 0.216 to 0.354 μg mL−1, respectively, as pH of a sandy loam and silty clay loam increased from 3 to 9. In contrast, adsorption on the sandy loam and silty clay loam for the same pH range decreased from 4.108 to 2.435 μg g−1 and from 2.850 to 1.484 μg g−1, respectively. Smaller but significant changes in adsorption were also observed for an organic soil over this range. Key words: Herbicide, fluridone, pH, uptake, soil adsorption
SOIL PERSISTENCE OF THIAMETURON (DPX M6316) AND PHYTOTOXICITY OF THE MAJOR DEGRADATION PRODUCT
Authors: SMITH A. E. , AUBIN A. J. , SHARMA M. P.
Published: March 2010

The persistence of the herbicidal ester (14C)thiameturon was studied at different temperature and moisture conditions in three Saskatchewan soils. In all soils at 20 °C and 85% field capacity, the (14C)ester underwent rapid hydrolysis to (14C)thiameturon acid. The hydrolysis was over 85% complete in 1 week, and more than 95% complete after 2 wk. The soil degradation of (14C)thiameturon acid was considerably slower than that of the parent ester. Transformation of (14C)thiameturon to acid in all soils at 85% field capacity was temperature dependent, being slowest at 10 °C, and fastest at 30 °C. Conversion to the acid was also moisture dependent. There was no hydrolysis in air-dry soils after 10 wk. At 50% field capacity 22% of the ester remained after 1 wk, and at field capacity less than 2% of the applied ester was recoverable after 1 wk. Soils treated with thiameturon acid at rates up to 500 μg g−1 exhibited no phytotoxicity to canola, lentil, or sugarbeet seedlings. Key words: Herbicide, thiameturon, persistence, phytotoxicity
PREDICTING UREA HYDROLYSIS AT LOW TEMPERATURES IN BRITISH COLUMBIA FOREST SOILS
Authors: MARSHALL V. G. , REYNOLDS S. , DANGERFIELD J. A.
Published: March 2010

Urease activity in 14 sites, representing a wide range of forest and soil types, was determined by a non-buffer method. Urease activity in L-H horizons ranged from 23–203 μg N hydrolyzed (g soil)−1 h−1 at 40 °C. In all soils, urease activity decreased dramatically with depth. At 0 °C, hydrolysis was estimated at 26.8 and 1.9 μg N g−1 h−1 for L-H and Bf horizons, respectively, for one site. Theoretical estimation of hydrolysis at 0 °C for the site with the lowest activity suggested that an operational application of urea (200 kg N ha−1) applied to snow could be hydrolyzed within 6 days in the rooting zone of all the soils studied. Key words: Urease activity, energy of activation, forest fertilization, Brunisols, Luvisols, Podzols
ALTERNATIVE METHOD FOR CARBOXYL GROUP DETERMINATION IN HUMIC SUBSTANCES
Authors: NOBILI M. De , CONTIN M. , LEITA L.
Published: March 2010

A new precipitation titration method, employing cetyltrimethylammonium (CTA+), is proposed for analysis of carboxyl groups of humic substances in solution. The method was tested with polyphenol-polycarboxylic acids standard solutions: recovery factors ranged from 0.94 to 1.09. Results obtained by performing precipitation of humic acids samples at pH = 9.8 and at 7.0 are compared with those obtained by the Ca-acetate method. The difference between the number of COOH per unit weight of humic preparation calculated by precipitation with CTA+ at pH = 7.0 and by the Ca-acetate exchange reaction ranged between 1 and 45%. In most samples overestimation of COOH groups by the Ca-acetate method appears to be higher than the mean relative error of the CTA+ precipitation method (5%). Key words: Carboxylic group determination, humic substances, cetyltrimethylammonium
FIELD SCALE PATTERNS OF SOIL WATER STORAGE FROM NON-CONTACTING MEASUREMENTS OF BULK ELECTRICAL CONDUCTIVITY
Authors: KACHANOSKI R. G. , WESENBEECK I. J. VAN , JONG E. De
Published: March 2010

Soil water storage (0–1.7 m) was measured every 10 m in a 660-m-long transect using a neutron probe and compared to bulk electrical conductivity, ECA, measurements obtained using noncontacting electomagnetic induction meters. Coherency analysis indicated a lack of correlation at scales less than 40 m. At scales greater than 40 m, ECA explained more than 80% of the variation of soil water storage. Measurement of ECA should be a simple and fast method of determining general field patterns of soil water storage. Key words: Spatial variability, soil water, coherency, electromagnetic induction
GRAZING IMPACTS ON INFILTRATION IN MIXED PRAIRIE AND FESCUE GRASSLAND ECOSYSTEMS OF ALBERTA
Authors: NAETH M. A. , ROTHWELL R. L. , CHANASYK D. S. , BAILEY A. W.
Published: March 2010

Infiltration capacity is generally reduced with increased grazing intensity and reduced range condition, mainly through vegetation and litter removal, soil structure deterioration, and compaction. Only one study has documented the effect of grazing on Canadian rangelands, necessitating further investigation. In this study, impacts of long-term grazing on infiltration were assessed in mixed prairie and fescue grassland ecosystems of southern and central Alberta, Canada. Grazing regimes were of light to very heavy intensities, grazed early, late, and continuously during the growing season. Ungrazed controls were evaluated at each site. Infiltration was measured with double ring infiltrometers. Heavy intensity and/or early season grazing had greater impact on infiltration than light intensity and/or late season grazing. In mixed prairie, initial and steady state infiltration rates in the control were 1.5 and 1.7 times higher, respectively, than those in the early season grazed treatment. In parkland fescue, initial rates were lowest in June grazed treatments and steady state rates were highest in light autumn grazed and control treatments. Initial infiltration rates in foothills fescue control and light grazed treatments were 1.5–2.3 times those in heavy and very heavy grazed treatments. Steady state rates were 1.5–2 times higher in light grazed and control treatments than in moderate, heavy, and very heavy grazed treatments. Key words: Infiltration, infiltration rate, grazing, rangelands
THE EFFECT OF DEEP BANDING N AND P FERTILIZER ON THE YIELD OF CANOLA (Brassica napus L.) AND SPRING WHEAT (Triticum aestivum L.)
Authors: NUTTALL W. F. , BUTTON R. G.
Published: March 2010

This study was conducted to determine if deep banding of P fertilizer was as efficient as placing P in a band with the seed. Phosphorus fertilizer (MAP) was deep banded at rates of 0, 10, 20, and 30 kg of P ha−1 which was compared with equal rates applied with the seed, and with one-half seed placed, one-half deep banded. The P rates were applied onto the same plots each year in a cropping sequence of canola (Brassica napus L.), four crops of wheat (Triticum aestivum L.) and then canola. Plots were located on a Melfort silty clay soil (Orthic Black Chernozem). In combination with MAP treatments, ammonium nitrate was applied by deep banding and by broadcast-incorporation to bring the total N application rate to 75 kg ha−1. Control treatments of 0–0 and 11–20 kg of N-P, respectively, were also included. In the first year of the experiment, when soil moisture conditions were dry, seed placement of the P fertilizer, on average, resulted in a significantly higher grain yield (1.01 t ha−1) of canola than deep banding (0.88 t ha−1). In the last year of the experiment, canola grain yields for the two placements were not significantly different (1.87 vs. 1.83 t ha−1). Over the 4 yr that wheat was grown there was no significant difference in grain yield between seed placed P and deep banding (2.97 vs. 2.95 t ha−1). Seed placement of P resulted in a higher grain yield (3.05 t ha−1) with N broadcast than with N deep banded (2.90 t ha−1), but with half-seed plus half-deep-banded P the yield was higher with N deep banded (3.08 t ha−1) than with broadcast-incorporated (2.87 t ha−1). The application of N and P over the 6 yr increased the available P in the soil from 7.5 (control) to 12.9 μg of P g−1 soil (N P treatments with 75 kg N ha−1). In general the application of P fertilizer either by deep banding or placement with the seed of the crop gave similar yields with the exception that at the low rates of P, seed placement was better for canola in the first year of the crop sequence. Key words: Deep banding, N, P, canola, wheat, placement
COMPARISON OF ION-SELECTIVE ELECTRODE METHODS FOR DETERMINING POTASSIUM Q/I RELATIONSHIPS
Authors: WANG JIAN , FARRELL RICHARD E. , SCOTT A. DUNCAN
Published: March 2010

Methods of characterizing the K + status of soils in terms of quantity-intensity (Q/I) relationships usually entail lengthy equilibration periods, filtrations, and multiple analyses of the filtrates. It has been established, however, that simpler and less time-consuming methods of determining Q/I parameters can be devised with ion-selective electrodes (ISEs). To this end, different ISE methods were developed and evaluated with suspensions of three Iowa soils and a successive-additions method of varying the added K+. The ISE methods, which were categorized on the basis of the electrochemical cell involved, were tested for their applicability to soil suspensions. Specifically, single-ISE (K- and Ca-ISEs vs. a double-junction reference electrode assembly with a 10 M LiOAc salt bridge), dual-ISE (K-ISE vs. Ca-ISE), and triple-ISE (K- and Ca-ISEs vs. Cl-ISE) methods were compared to ascertain the best means of determining the ΔK (gain or loss of dissolved K) and CR [concentration ratio: CK/(CCa+Mg)1/2] terms of the Q/I relationships. The Q/I curves for the three soils and the specific parameters of Q/I relationships were also determined with the different ISE methods. It was concluded that the combined approach of using the triple-ISE method with soil suspensions offers the best means of carrying out simple, rapid, and liquid junction free determinations of potassium Q/I relationships. Key words: Electrochemical cell, liquid junction, concentration ratio, potential buffering capacity
IRRIGATION SUITABILITY OF SOLONETZIC SOILS IN THE COUNTY OF NEWELL, ALBERTA
Authors: BENNETT D. R. , ENTZ T.
Published: March 2010

A 5-yr study was conducted in the County of Newell to monitor soil salinity and sodicity, water-table levels and crop production on Solonetzic soil associations under normal irrigation management practices. All soil associations consisted of at least 50 percent Solonetzic Order soils, with Brown Solod as the dominant subgroup at all but one site. Changes in soil quality were monitored through regular measurements of water-table levels, annual fall sampling and chemical analysis of soils. Irrigation practises used by farmers did not permanently raise water-table levels at any of the sites irrigated by center pivots. Changes in soil salinity or sodicity as a result of irrigation were generally not statistically significant, suggesting that the salt status of soils at most sites did not change appreciably over the 5-yr period. The relatively low productive capability of land units dominated by Solonetzic soils was evident in the low yield and by a high degree of variability in yield within individual sites. Careful irrigation management partially compensated for some of the soil limitations in these Solonetzic soil landscapes; however, due to the low productivity observed, modification of existing land classification standards to allow irrigation of Solonetzic soils is not presently recommended. Key words: Irrigation suitability, Solonetzic soils, productive capability
Use of a Standardized Patient Exercise to Assess Core Competencies During Fellowship Training
Authors: Barry Curtis T. , Avissar Uri , Asebrook Maureen , Sostok Michael A. , Sherman Kenneth E. , Zucker Stephen D.
Published: March 2010

Background

The Accreditation Council for Graduate Medical Education requires fellows in many specialties to demonstrate attainment of 6 core competencies, yet relatively few validated assessment tools currently exist. We present our initial experience with the design and implementation of a standardized patient (SP) exercise during gastroenterology fellowship that facilitates appraisal of all core clinical competencies.

Methods

Fellows evaluated an SP trained to portray an individual referred for evaluation of abnormal liver tests. The encounters were independently graded by the SP and a faculty preceptor for patient care, professionalism, and interpersonal and communication skills using quantitative checklist tools. Trainees' consultation notes were scored using predefined key elements (medical knowledge) and subjected to a coding audit (systems-based practice). Practice-based learning and improvement was addressed via verbal feedback from the SP and self-assessment of the videotaped encounter.

Results

Six trainees completed the exercise. Second-year fellows received significantly higher scores in medical knowledge (55.0 ± 4.2 [standard deviation], P  =  .05) and patient care skills (19.5 ± 0.7, P  =  .04) by a faculty evaluator as compared with first-year trainees (46.2 ± 2.3 and 14.7 ± 1.5, respectively). Scores correlated by Spearman rank (0.82, P  =  .03) with the results of the Gastroenterology Training Examination. Ratings of the fellows by the SP did not differ by level of training, nor did they correlate with faculty scores. Fellows viewed the exercise favorably, with most indicating they would alter their practice based on the experience.

Conclusions

An SP exercise is an efficient and effective tool for assessing core clinical competencies during fellowship training.
Strategies for Effective On-Call Supervision for Internal Medicine Residents: The Superb/Safety Model
Authors: Farnan Jeanne M. , Johnson Julie K. , Meltzer David O. , Harris Ilene , Humphrey Holly J. , Schwartz Alan , Arora Vineet M.
Published: March 2010

Background

Supervision is central to resident education and patient safety, yet there is little published evidence to describe a framework for clinical supervision. The aim of this study was to describe supervision strategies for on-call internal medicine residents.

Methods

Between January and November 2006, internal medicine residents and attending physicians at a single hospital were interviewed within 1 week of their final call on the general medicine rotation. Appreciative inquiry and critical incident technique were used to elicit perspectives on ideal and suboptimal supervision practices. A representative portion of transcripts were analyzed using an inductive approach to develop a coding scheme that was then applied to the entire set of transcripts. All discrepancies were resolved via discussion until consensus was achieved.

Results

Forty-four of 50 (88%) attending physicians and 46 of 50 (92%) eligible residents completed an interview. Qualitative analysis revealed a bidirectional model of suggested supervisory strategies, the “SUPERB/SAFETY” model; an interrater reliability of 0.70 was achieved. Suggestions for attending physicians providing supervision included setting expectations, recognizing uncertainty, planning communication, having easy availability, reassuring residents, balancing supervision, and having autonomy. Suggested resident strategies for seeking supervision from attending physicians included seeking input early, contacting for active clinical decisions or feeling uncertain, end of life issues, transitions in care, or help with systems issues. Common themes suggested by trainees and attending physicians included easy availability and preservation of resident decision-making autonomy.

Discussion

Residents and attending physicians have explicit expectations for optimal supervision. The SUPERB/SAFETY model of supervision may be an effective resource to enhance the clinical supervision of residents.
Implementation and Initial Evaluation of an Academic Career Development Curriculum for Fellows
Authors: Domino Steven E. , Reynolds R. Kevin
Published: March 2010

Objective

To develop and evaluate an academic career development curriculum.

Methods

We anonymously surveyed 25 fellows and advanced trainees in 9 obstetrics and gynecology subspecialty fellowships prior to the start of an academic career development common curriculum in 2007. Results were compared with responses from the same survey given at the completion of the 2-year program to guide and improve the curriculum. Fourteen surveys were completed for both administrations.

Results

Most fellows expressed the desire to pursue academic careers and planned to present and publish research from their fellowship in both surveys. After completing the curriculum, fellows reported overall improvement in self-appraised confidence for speaking at national meetings and preparing a research grant. The most substantial change in self-assessment was increased awareness and utilization of departmental research support personnel. Elements of training that showed improvement but were not main topics of core sessions included the frequency of constructive feedback from mentors and peers, and frequency of discussion of research ethics.

Conclusion

Instituting an academic career development curriculum for obstetrics and gynecology fellows was associated with increased self-appraised confidence in specific academic skills as assessed by anonymous survey.
Developing a Predictive Model to Assess Applicants to an Internal Medicine Residency
Authors: Neely David , Feinglass Joseph , Wallace Warren H.
Published: March 2010

Background

Residency programs strive to accurately assess applicants' qualifications and predict future performance. However, there is little evidence-based guidance on how to do this. The aim of this study was to design an algorithm for ranking applicants to an internal medicine residency program.

Methods

Ratings of overall performance in residency were compared to application characteristics of 230 graduating residents from 2000–2005. We analyzed 5 characteristics of the application: medical school, overall medical school performance, performance in junior medicine clerkship, United States Medical Licensing Examination (USMLE) Step 1 score, and interview ratings. Using bivariate correlations and multiple regression analysis, we calculated the association of each characteristic with mean performance ratings during residency.

Results

In multiple regression analysis, the most significant application factors (r2  =  0.22) were the quality of the medical school and the applicant's overall performance in medical school (P < .001).

Conclusion

This data has allowed the creation of a weighted algorithm to rank applicants that uses 4 application factors—school quality, overall medical school performance, medicine performance, and USMLE Step 1 score.
The Associations Between Residents' Behavior and the Thomas-Kilmann Conflict MODE Instrument
Authors: Ogunyemi Dotun , Fong Susie , Elmore Geoff , Korwin Devra , Azziz Ricardo
Published: March 2010

Objective

To assess if the Thomas-Kilmann Conflict MODE Instrument predicts residents’ performance.

Study Design

Nineteen residents were assessed on the Thomas-Kilmann conflict modes of competing, collaborating, compromising, accommodating, and avoiding. Residents were classified as contributors (n  =  6) if they had administrative duties or as concerning (n  =  6) if they were on remediation for academic performance and/or professionalism. Data were compared to faculty evaluations on the Accreditation Council for Graduate Medical Education (ACGME) competencies. P value of < .05 was considered significant.

Results

Contributors had significantly higher competing scores (58% versus 17%; P  =  .01), with lower accommodating (50% versus 81%; P 5 .01) and avoiding (32% versus 84%; P  =  .01) scores; while concerning residents had significantly lower collaborating scores (10% versus 31%; P  =  .01), with higher avoiding (90% versus 57%; P  =  .006) and accommodating (86% versus 65%; P  =  .03) scores.

There were significant positive correlations between residents’ collaborating scores with faculty ACGME competency evaluations of medical knowledge, communication skills, problem-based learning, system-based practice, and professionalism. There were also positive significant correlations between compromising scores and faculty evaluations of problem-based learning and professionalism with negative significant correlations between avoiding scores and faculty evaluations of problem-based learning, communication skills and professionalism.

Conclusions

Residents who successfully execute administrative duties are likely to have a Thomas-Kilmann profile high in collaborating and competing but low in avoiding and accommodating. Residents who have problems adjusting are likely to have the opposite profile. The profile seems to predict faculty evaluation on the ACGME competencies.
An Assessment Tool for Aseptic Technique in Resident Physicians: A Journey Towards Validation in the Real World of Limited Supervision
Authors: Lypson Monica L. , Hamstra Stanley J. , Ross Paula T. , Gruppen Larry D. , Colletti Lisa M.
Published: March 2010

Purpose

The purpose of this study was to describe the validation process for assessing an instrument to assess residents' aseptic technique skills.

Methods

The validation study entailed comparisons of the performance of aseptic technique procedures between postgraduate year–1 (PGY-1) surgical residents and PGY-2/3 surgical residents. We also compared the performance of PGY-1 surgical residents from 2 different academic years for the same procedures. Finally, we compared the performance of novices (medical students) and experts (operating room nurses) in an effort to determine validity.

Results

Our initial analysis found no significant difference between the performance of PGY-1 (mean score, 75.8) and PGY-2/3 (mean score, 75.6) surgical residents for aseptic technique (t(55)  =  0.84, P  =  0.404). Further investigation of validity was obtained to determine whether the no difference results reflected a lack of reliability or validity or a true equivalence between the 2 cohorts. The comparison of novices and experts produced the following findings. For reliability, the internal consistency of the checklist for each of the 2 raters was 0.87 and 0.71 (Cronbach α), interrater reliability was 0.74, with P < 0.001 (intraclass correlation coefficient) for the global scale. (Internal consistency was done within instrument, ie, between items not between raters.) For validity, operating room nurses outperformed students on the global scale (t14  =  7.47, P < 0.0001 and t(14)  =  10.66, P < 0.0001 for the 2 raters, respectively) and on several checklist items. The effect size values for raters were large (Cohen d  =  3.0 and 4.4), providing validity evidence for the ability of this assessment to detect difference in performance on this task.

Conclusion

The validation study showed that the instrument exhibited reliability and evidence for validity, making it useful for the assesment of aseptic technique skills in different specialties. Programs may want to consider using a validated instrument to check competence given that appropriate use of sterile technique frequently occurs in the context of unsupervised activities. Further work is needed to enhance resident skills in the area of aspectic technique because of limited improvement despite additional clinical experience.
How Residents View Their Clinical Supervision: A Reanalysis of Classic National Survey Data
Authors: Baldwin De Witt C. , Daugherty Steven R. , Ryan Patrick M.
Published: March 2010

Background

Concerns over patient safety have made adequacy of clinical supervision an important component of care in teaching settings. Yet, few studies have examined residents' perceptions about the quality and adequacy of their supervision. We reanalyzed data from a survey conducted in 1999 to explore residents' perspectives on their supervision.

Methods

A national, multispecialty survey was distributed in 1999 to a 14.5% random sample of postgraduate year 2 (PGY-2) and PGY-3 residents. The response rate was 64.4%. Residents (n  =  3604) were queried about how often they had cared for patients “without adequate supervision” during their preceding year of training.

Results

Of responding residents, 21% (n  =  737) reported having seen patients without adequate supervision at least once a week, with 4.5% saying this occurred almost daily. Differences were found across specialties, with 45% of residents in ophthalmology, 46% in neurology, and 44% in neurosurgery stating that they had experienced inadequate supervision at least once a week throughout the year, compared with 1.5% of residents in pathology and 3% in dermatology. Inadequate supervision was found to be inversely correlated with residents' positive ratings of their learning, time with attendings, and overall residency experience (P < .001 for all), and positively correlated with negative features of training, including medical errors, sleep deprivation, stress, conflict with other medical personnel, falsifying patient records, and working while impaired (P < .001).

Conclusions

In residents' self-report, inadequate clinical supervision correlates with other reported negative aspects of training. Collectively, this may detrimentally affect resident learning and patient safety.
A Strategy to Reduce Interruptions at Hospital Morning Report
Authors: Wieland Mark L. , Loertscher Laura L. , Nelson Darlene R. , Szostek Jason H. , Ficalora Robert D.
Published: March 2010

Background

The learning atmosphere of hospital morning report is frequently interrupted by nonurgent beeper pages to participating residents.

Intervention

During 176 consecutive internal medicine morning reports, 1 of the 4 chief residents at a single academic medical center collected and answered house staff pages during the 30-minute conference.

Results

A total of 884 pages were answered during this period. Of these, 743 could wait until after the end of morning report, resulting in more than 4 interruptions averted per session. Over half of the pages were from nursing personnel. There was no significant decrease in the total number of pages or nurse pages during the observation period.

Discussion

In summary, our simple system of holding intern pages resulted in a dramatic reduction in interruptions during hospital morning report.
Disparity Between Resident and Attending Physician Perceptions of Intraoperative Supervision and Education
Authors: Levinson Kimberly L. , Barlin Joyce N. , Altman Kristiina , Satin Andrew J.
Published: March 2010

Background

As part of an ongoing evaluation of our residency program, a needs assessment was performed to assess resident and attending perspectives on current methods of surgical skills training in the operating room.

Methods

Participants included obstetrics-gynecology residents and faculty at a university program. Two surveys were developed and validated. Results were analyzed with 2-sample t tests, comparing Likert scores. Findings were significant if the difference between means was >1.

Results

Thirty of 31 residents and 40 of 60 attending physicians responded to the survey. Residents and attending physicians agreed that the surgical skills training program needs improvement (difference in mean, −0.39; confidence interval [CI]: −0.98 to 0.20). The areas of most disagreement were regarding feedback on surgical skills and instrument handling (difference in mean, 2.53; CI: 1.81–3.26, and difference in mean, 2.24; CI: 1.44–3.05).

Conclusions

A significant proportion of surgical skills training during residency occurs as on-the-job training, and operating room time provides a key learning opportunity. This report demonstrates that there is a noteworthy difference in the perception of attending physicians and residents about the quality of teaching and feedback that is currently occurring in the operating room. The difference in perspectives among residents and attending physicians reported in this survey suggests a need for improved communication and systematic feedback in order to capitalize on operating room time as a critical surgical skills training arena.
Algal Indicators of Trophic Lake Types
Authors: RAWSON D.S.
Published: March 2010

The dominant species of algae in the Great Lakes and in the large oligotrophic lakes of western Canada are not those commonly quoted as oligotrophic indicators. It is suggested that this apparent discrepancy may be due to the lack of sufficiently detailed taxonomic information, to the non‐existence of oligotrophic indicators, or to the fact that oligotrophy of these lakes is essentially morphometric rather than edaphic. The utility of phytoplankton quotients and the problem of numbers of species versus dominant species are discussed.
Population Dynamics of the Marine Clam, Mya arenaria1
Authors: AYERS JOHN C.
Published: March 2010

From present spawning and survival data, it is calculated that stable local populations of Mya require an average annual production, per spawning pair, of 40 spat which both survive and remain in the spawning area. The sizes of larva populations which survive and remain in the area under various flushing rates and mortalities are calculated. From this and the 40 spat/pair/year level the suitability of estuaries or embayments as sites for Mya cultivation may be judged when local flushing rates and mortality coefficients are known. A formula for estimating the harvestable fraction of the existing population under local flushing rate and mortality conditions has been derived. The method, combined with the local oceanography, adequately explains the anomalous history of Mya production in the harbor of Barnstable, Massachusetts.
Artificial Eutrophication of Lake Washington1
Authors: EDMONDSON W. T. , ANDERSON G. C. , PETERSON DONALD R.
Published: March 2010

Lake Washington has been receiving increasing amounts of treated sewage, and appears to be responding by changes in kind and quantity of biota. In 1933 and 1950 the dominant phytoplankton organisms were Anabaena and various diatoms and dinoflagellates, but in 1955, apparently for the first time, there was a large population of the blue‐green alga, Oscillatoria rubescens, a species which makes nuisance blooms in a number of lakes. A great increase in the hypolimnetic oxygen deficit is taken as evidence of increased productivity; the deficit was 1.18 mg/cm2/month in 1933, 2.00 in 1950, and 3.13 in 1955. There is a fairly close relation between the decrease of oxygen and increase in phosphate concentration in the hypolimnion between measurements, a much less close relation with the chlorophyll concentration in the epilimnion.
The Measurement of Primary Production1
Authors: RYTHER JOHN H.
Published: March 2010

A discussion is presented of the measurement of primary production by short‐term experimental methods and by measurement of in situ environmental changes occurring over longer periods of time. The methods described include the measurement of photosynthesis by oxygen production, carbon dioxide assimilation and the associated pH change, and uptake of radioactive carbon (C14). In situ changes in the standing crop and the concentration of inorganic plant nutrients are also discussed, and the possibility explored of relating the rate of uptake of radioactive inorganic tracers to primary production. The relationship between chlorophyll and photosynthesis is reviewed and some new experimental evidence is presented which indicates the possibility of using chlorophyll concentration as an index of primary production. In the discussions of each method emphasis is placed on sensitivity, reliability, and the interpretation of the data.
Primary Production in Flowing Waters1
Authors: ODUM HOWARD T.
Published: March 2010

Respiration, photosynthetic production, and diffusion interact to produce the daily curve of oxygen change in a segment of flowing water. Conversely, the observed curves of oxygen in streams can be used to calculate the component rates of production, respiration, and diffusion. New production values obtained with these analyses of oxygen curves from various sources, as well as a few previously existing estimates of primary production, indicate a generally higher rate of production in flowing waters than in other types of aquatic environments.

The ratio of total primary production to total community respiration is used to classify communities quantitatively according to their predominantly heterotrophic or autotrophic characteristics. Longitudinal succession within a stream tends to modify the ratio towards unity from higher values for autotrophic and from lower values for heterotrophic communities. The behavior of this ratio is described for the annual cycle in a stream, for the sequence of pollution recovery, and for diverse types of communities.
Body Size and Number of Eggs in Diaptomids, as Related to Water Renewal in Mountain Lakes
Authors: RAVERA OSCAR , TONOLLI VITTORIO
Published: March 2010

The study of 32 populations of Arctodiaptomus bacillifer and of 14 populations of Acanthodiaptomus denticornis has shown a good correlation between the body size of egg‐carrying females and the number of eggs actually carried by the same. Furthermore, these characters are correlated with the extent of the water renewal of each fake, based upon the ratio: area of drainage basin/area of lake. It is suggested that in any population, selection may favor females able to produce a number of eggs correlated with and balanced against the losses which outflowing waters induce in the pelagic stages of the population.
The Accumulation and Exchange of Strontium by Marine Planktonic Algae1
Authors: RICE T. R.
Published: March 2010

The radioactivity taken up by each of twelve species of algae, grown in a mixture of radioactive strontium and yttrium, was separated into that due to each isotope. This was accomplished by following the decay curve of the activity in the algae. The uptake of radioactive strontium and yttrium was followed at frequent intervals in Carteria cells grown in medium containing these two isotopes. The removal of yttrium from the medium by Carteria was shown to be due to adsorption on the surface, whereas strontium was taken into the cells.

It was found that Carteria could not divide in the absence of calcium in the medium. Neither could strontium be substituted for calcium in the metabolism of Carteria cells. When other factors were kept constant, the amount of strontium removed by the cells was dependent upon the strontium concentration in the medium.

With the radioisotopic dilution technique, the number of times strontium is concentrated by Carteria and Nitzschia over the amount occurring in sea water was determined. It was demonstrated that the division rate, the age of the culture, and the hydrogen ion concentration all influenced the number of times strontium was concentrated in Carteria cells.

Exchange experiments showed that radioactive strontium was not lost from Carteria cells unless the medium contained a chelating compound. Some loss of radioactive strontium from Carteria cells occurred when the cells were filter‐washed with several different types of solutions.