bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitrous Oxide Emissions from a Northern Great Plains Soil as Influenced by Nitrogen Management and Cropping Systems
Authors: Dusenbury M. P. , Engel R. E. , Miller P. R. , Lemke R. L. , Wallander R. 
Published: February 2008

AbstractField measurements of N2O emissions from soils are limited for cropping systems in the semiarid northern Great Plains (NGP). The objectives were to develop N2O emission‐time profiles for cropping systems in the semiarid NGP, define important periods of loss, determine the impact of best management practices on N2O losses, and estimate direct N fertilizer‐induced emissions (FIE). No‐till (NT) wheat (Triticum Aestivum L.)‐fallow, wheat‐wheat, and wheat‐pea (Pisum sativum), and conventional till (CT) wheat‐fallow, all with three N regimes (200 and 100 kg N ha−1 available N, unfertilized control); plus a perennial grass‐alfalfa (Medicago sativa L.) system were sampled over 2 yr using vented chambers. Cumulative 2‐yr N2O emissions were modest in contrast to reports from more humid regions. Greatest N2O flux activity occurred following urea‐N fertilization (10‐wk) and during freeze–thaw cycles. Together these periods comprised up to 84% of the 2‐yr total. Nitrification was probably the dominant process responsible for N2O emissions during the post‐N fertilization period, while denitrification was more important during freeze–thaw cycles. Cumulative 2‐yr N2O‐N losses from fertilized regimes were greater for wheat‐wheat (1.31 kg N ha−1) than wheat‐fallow (CT and NT) (0.48 kg N ha−1), and wheat‐pea (0.71 kg N ha−1) due to an additional N fertilization event. Cumulative losses from unfertilized cropping systems were not different from perennial grass‐alfalfa (0.28 kg N ha−1). Tillage did not affect N2O losses for the wheat‐fallow systems. Mean FIE level was equivalent to 0.26% of applied N, and considerably below the Intergovernmental Panel on Climate Change mean default value (1.25%).
The Impact of Agricultural Runoff on the Quality of Two Streams in Vegetable Farm Areas in Ghana
Authors: Ntow William J. , Drechsel Pay , Botwe Benjamin Osei , Kelderman Peter , Gijzen Huub J. 
Published: February 2008

AbstractA study of two small streams at Akumadan and Tono, Ghana, was undertaken during the rain and dry season periods between February 2005 and January 2006 to investigate the impact of vegetable field runoff on their quality. In each stream we compared the concentration of current‐use pesticides in one site immediately upstream of a vegetable field with a second site immediately downstream. Only trace concentrations of endosulfan and chlorpyrifos were detected at both sites in both streams in the dry season. In the wet season, rain‐induced runoff transported pesticides into downstream stretches of the streams. Average peak levels in the streams themselves were 0.07 μg L−1 endosulfan, 0.02 μg L−1 chlorpyrifos (the Akumadan stream); 0.04 μg L−1 endosulfan, 0.02 μg L−1 chlorpyrifos (the Tono stream). Respective average pesticide levels associated with streambed sediment were 1.34 and 0.32 μg kg−1 (the Akumadan stream), and 0.92 and 0.84 μg kg−1 (the Tono stream). Further investigations are needed to establish the potential endosulfan and chlorpyrifos effects on aquatic invertebrate and fish in these streams. Meanwhile measures should be undertaken to reduce the input of these chemicals via runoff.
Managing Broiler Litter Application Rate and Grazing to Decrease Watershed Runoff Losses
Authors: Sistani K. R. , Brink G. E. , Oldham J. L. 
Published: February 2008

AbstractPasture management and broiler litter application rate are critical factors influencing the magnitude of nutrients being transported by runoff from fields. We investigated the impact of pasture management and broiler litter application rate on nutrient runoff from bermudagrass (Cynodon dactylon) pastures. The experiment was conducted on a Ruston fine sandy loam with a factorial arrangement on 21 large paddocks. Runoff water was collected from natural rainfall events from 2001 to 2003. Runoff water and soil samples were analyzed for nutrients and sediments. Runoff was generally greater (29%) from grazed than hayed pastures regardless of the litter application rate. There was greater inorganic N in the runoff from grazed paddocks when litter rate was based on N rather than P. The mean total P loss per runoff event for all treatments ranged from 7 to 45 g ha−1 and the grazed treatment with litter applied on N basis had the greatest total P loss. Total dissolved P was the dominant P fraction in the runoff, ranging from 85% to 93% of the total P. The soluble reactive P was greater for treatments with litter applied on N basis regardless of pasture management. Runoff total sediments were greater for N‐based litter application compared to those which received litter on P basis. Our results indicate that litter may be applied on N basis if the pasture is hayed and the soil P is low. In contrast, litter rates should be based on a P‐basis if pasture is grazed.
The Locus for Hypoglycemic Detection Shifts With the Rate of Fall in Glycemia
Authors: Saberi Maziyar , Bohland MaryAnn , Donovan Casey M. 
Published: February 2008

OBJECTIVE—To ascertain whether portal glucose sensing extends beyond the portal vein to the superior mesenteric vein and then test whether the role of portal–superior mesenteric glucose sensors varies with the rate of fall in glycemia.
RESEARCH DESIGN AND METHODS—Chronically cannulated rats underwent afferent ablation of the portal vein (PV) or portal and superior mesenteric veins (PMV) or sham operation (control). One week later, animals underwent hyperinsulinemic-hypoglycemic clamps in which the hypoglycemic nadir, 2.48 ± 0.06 mmol/l, was reached at a rate of decline in glucose of −0.09 or −0.21 mmol · l−1 · min−1 (PMV and control only). Additional PMV and control animals received an intravenous injection of the glucopenic agent 2-deoxyglucose.
RESULTS—Inducing hypoglycemia slowly, at a rate of −0.09 mmol · l−1 · min−1, resulted in a 26-fold increase in epinephrine (23.39 ± 0.62 nmol/l) and 12-fold increase in norepinephrine (11.42 ± 0.92 nmol/l) for controls (P &lt; 0.001). The epinephrine response to hypoglycemia was suppressed by 91% in PMV (2.09 ± 0.07 nmol/l) vs. 61% in PV (9.05 ± 1.59 nmol/l) (P &lt; 0.001). The norepinephrine response to hypoglycemia was suppressed by 94 and 80% in PMV and PV, respectively, compared with that in controls. In contrast, when arterial glucose was lowered to 2.49 ± 0.06 mmol/l within 20 min, no significant differences were observed in the catecholamine responses for PMV and controls over the first 45 min of hypoglycemia (20–65 min). Only at min 105 were catecholamines significantly lower for PMV vs. controls. Injection of 2-deoxyglucose induced a very rapid sympathoadrenal response with no significant differences between PMV and controls.
CONCLUSIONS—The critical locus for hypoglycemic detection shifts away from the portal-mesenteric vein to some other loci (e.g., the brain) when hypoglycemia develops rapidly.
Association of IL-1ra and Adiponectin With C-Peptide and Remission in Patients With Type 1 Diabetes
Authors: Pfleger Christian , Mortensen Henrik B. , Hansen Lars , Herder Christian , Roep Bart O. , Hoey Hillary , Aanstoot Henk-Jan , Kocova Mirjana , Schloot Nanette C. ,   on behalf of the Hvidøre Study Group on Childhood Diabetes
Published: February 2008

OBJECTIVE—We investigated the association of anti-inflammatory cytokine interleukin (IL)-1 receptor antagonist (IL-1ra), adiponectin, proinflammatory cytokines IL-1β, IL-6, and CCL2, and tumor necrosis factor-α with β-cell function, metabolic status, and clinical remission in patients with recent-onset type 1 diabetes.RESEARCH DESIGN AND METHODS—Serum was obtained from 256 newly diagnosed patients (122 males and 134 females, median age 9.6 years). Stimulated C-peptide, blood glucose, and A1C were determined in addition to circulating concentration of cytokines at 1, 6, and 12 months after diagnosis. Analyses were adjusted for sex, age, and BMI percentile.RESULTS—Anti-inflammatory IL-1ra was positively associated with C-peptide after 6 (P = 0.0009) and 12 (P = 0.009) months. The beneficial association of IL-1ra on β-cell function was complemented by the negative association of IL-1β with C-peptide after 1 month (P = 0.009). In contrast, anti-inflammatory adiponectin was elevated in patients with poor metabolic control after 6 and 12 months (P &lt; 0.05) and positively correlated with A1C after 1 month (P = 0.0004). Proinflammatory IL-6 was elevated in patients with good metabolic control after 1 month (P = 0.009) and showed a positive association with blood glucose disposal after 12 months (P = 0.047).CONCLUSIONS—IL-1ra is associated with preserved β-cell capacity in type 1 diabetes. This novel finding indicates that administration of IL-1ra, successfully improving β-cell function in type 2 diabetes, may also be a new therapeutic approach in type 1 diabetes. The relation of adiponectin and IL-6 with remission and metabolic status transfers observations from in vitro and animal models into the human situation in vivo.
Ventromedial Hypothalamic Glucokinase Is an Important Mediator of the Counterregulatory Response to Insulin-Induced Hypoglycemia
Authors: Levin Barry E. , Becker Thomas C. , Eiki Jun-ichi , Zhang Bei B. , Dunn-Meynell Ambrose A. 
Published: February 2008

OBJECTIVE—The counterregulatory response to insulin-induced hypoglycemia is mediated by the ventromedial hypothalamus (VMH), which contains specialized glucosensing neurons, many of which use glucokinase (GK) as the rate-limiting step in glucose's regulation of neuronal activity. Since conditions associated with increased VMH GK expression are associated with a blunted counterregulatory response, we tested the hypothesis that increasing VMH GK activity would similarly attenuate, while decreasing GK activity would enhance the counterregulatory response to insulin-induced hypoglycemia.
RESEARCH DESIGN AND METHODS—The counterregulatory response to insulin-induced hypoglycemia was evaluated in Sprague-Dawley rats after bilateral VMH injections of 1) a GK activator drug (compound A) to increase VMH GK activity, 2) low-dose alloxan (4 μg) to acutely inhibit GK activity, 3) high-dose alloxan (24 μg), or 4) an adenovirus expressing GK short hairpin RNA (shRNA) to chronically reduce GK expression and activity.
RESULTS—Compound A increased VMH GK activity sixfold in vitro and reduced the epinephrine, norepinephrine, and glucagon responses to insulin-induced hypoglycemia by 40–62% when injected into the VMH in vivo. On the other hand, acute and chronic reductions of VMH GK mRNA or activity had a lesser and more selective effect on increasing primarily the epinephrine response to insulin-induced hypoglycemia by 23–50%.
CONCLUSIONS—These studies suggest that VMH GK activity is an important regulator of the counterregulatory response to insulin-induced hypoglycemia and that a drug that specifically inhibited the rise in hypothalamic GK activity after insulin-induced hypoglycemia might improve the dampened counterregulatory response seen in tightly controlled diabetic subjects.
Persistence of Altered Movement Patterns During a Sit-to-Stand Task 1 Year Following Unilateral Total Knee Arthroplasty
Authors: Farquhar Sara J , Reisman Darcy S , Snyder-Mackler Lynn 
Published: February 2008

Background and PurposeFollowing total knee arthroplasty (TKA), quadriceps femoris muscle strength (force-generating capacity) and functional test scores improve but continue to be lower than those in people without injury. Analysis of the sit-to-stand (STS) task demonstrated side-to-side differences in subjects with TKA, as well as differences between subjects with TKA and control subjects. It was hypothesized that, when using a self-selected starting position, subjects 1 year following TKA would show improvements in strength and movement patterns but would continue to show asymmetries of angles and moments at the hips and knees.Subjects and MethodsTwenty-four subjects (12 subjects with unilateral TKA and 12 control subjects) were recruited; those with TKA were tested 3 months and 1 year following surgery. Motion analysis of an STS task was synchronized with 2 force platforms and electromyography. Outcome measures included joint angles and moments, electromyography, vertical ground reaction forces, muscle strength, and functional performance tests.ResultsSubjects with TKA showed improvements in symmetry of motion, strength, and functional performance from 3 months to 1 year following TKA. Compared with control subjects, subjects with TKA relied on increased hip flexion and a larger hip extensor moment to perform the STS task.Discussion and ConclusionThe increased hip extensor moment demonstrated that subjects adopted a strategy to avoid the use of the quadriceps femoris muscle, yet this strategy persisted as quadriceps femoris muscle strength improved. This pattern may be a learned movement pattern that may not resolve without retraining.
Usefulness of the Berg Balance Scale in Stroke Rehabilitation: A Systematic Review
Authors: Blum Lisa , Korner-Bitensky Nicol 
Published: February 2008

BackgroundIn a recent study of 655 physical therapists working with a stroke population, the Berg Balance Scale (BBS) was identified as the most commonly used assessment tool across the continuum of stroke rehabilitation. Given the widespread popularity of the BBS, it is important to critically appraise the BBS for its use with a stroke population.ObjectiveThe purposes of this study were to conduct a systematic review of the psychometric properties of the BBS specific to stroke and to identify strengths and weaknesses in its usefulness for stroke rehabilitation.ResultsTwenty-one studies examining the psychometric properties of the BBS with a stroke population were retrieved. Internal consistency was excellent (Cronbach alpha=.92–.98) as was interrater reliability (intraclass correlation coefficients [ICCs]=.95–.98), intrarater reliability (ICC=.97), and test-retest reliability (ICC=.98). Sixteen studies focused on validity and generally found excellent correlations with the Barthel Index, the Postural Assessment Scale for Stroke Patients, Functional Reach Test, the balance subscale of Fugl-Meyer Assessment, the Functional Independence Measure, the Rivermead Mobility Index (except for weight shift and step-up items), and gait speed. Berg Balance Scale scores predicted length of stay, discharge destination, motor ability at 180 days poststroke, and disability level at 90 days, but these scores were not predictive of falls. Eight studies focused on responsiveness; all reported moderate to excellent sensitivity. Three studies found floor or ceiling effects.Discussion and ConclusionThe BBS is a psychometrically sound measure of balance impairment for use in poststroke assessment. Given the floor and ceiling effects, clinicians may want to use the BBS in conjunction with other balance measures.
The influence of exercise during growth on ultrasonographic parameters of the superficial digital flexor tendon of young Thoroughbred horses
Authors: MOFFAT P. A. , FIRTH E. C. , ROGERS C. W. , SMITH R. K. W. , BARNEVELD A. , GOODSHIP A. E. , KAWCAK C. E. , McILWRAITH C. W. , van WEEREN P. R. 
Published: February 2008

SummaryReasons for performing study: Conditioning by early training may influence the composition of certain musculoskeletal tissues, but very few data exist on its effect during growth on tendon structure and function.Objectives: To investigate whether conditioning exercise in young foals would lead to any ultrasonographically detectable damage to the superficial digital flexor tendon or an increase in cross‐sectional area (CSA).Methods: Thirty‐three Thoroughbred foals reared at pasture were allocated to 2 groups: control (PASTEX) allowed exercise freely at pasture; andCONDEX, also at pasture, began conditioning exercise from mean age 21 days over 1030 m on a purpose‐built oval grass track, for 5 days/week until mean age 18 months. Foals were observed daily, and underwent orthopaedic examination monthly. Ultrasonographic images of the superficial digital flexor tendon (SDFT) at the mid‐metacarpal level of both forelimbs were obtained in all foals at ages 5, 8, 12, 15 and 18 months. CSA was validated (r2= 0.89) by determining CSA from digital photographs of the transected SDFT surface from 12 of the horses necropsied at age 17.1 months.Results: There was no clinical or ultrasonographic evidence of tendonopathy in either group and the greatest increase in mean CSA in both groups occurred between age 5 and 8 months. Across all age categories, there was no significant difference in mean CSA between the left and right limbs, or colts and fillies; there was a trend towards a larger CSA in theCONDEXgroup (P = 0.058).Conclusions: There was no conclusive evidence for a structural adaptive hypertrophy of the SDFT, probably because the regimen was insufficiently rigorous or because spontaneous pasture exercise may induce maximal development of energy storing tendons.Potential relevance: A moderate amount of early conditioning exercise against a background of constant exercise at pasture is not harmful to the development of the flexor tendons.
Ocular penetration of intravenously administered enrofloxacin in the horse
Authors: DIVERS T. J. , IRBY N. L. , MOHAMMED H. O. , SCHWARK W. S. 
Published: February 2008

SummaryReason for performing study: Information on antibiotic concentrations in the equine eye following systemic therapy is limited. Reports thatLeptospiraspp. are frequently present in the eyes of horses with recurrent uveitis, emphasises a need for studies on ocular concentrations of specific antibiotics.Hypotheses: 1) Enrofloxacin, administered i.v. at 7.5 mg/kg bwt q. 24 h, results in aqueous humour concentrations greater than the reported minimum inhibitory concentration (MIC) forLeptospira pomona.2) Aqueous humour paracentesis sufficiently disrupts the blood‐aqueous humour barrier (BAB) to cause an increase in aqueous humour protein and enrofloxacin concentrations.Methods: Aqueous humour enrofloxacin and total protein concentrations were determined in 6 healthy, mature horses after i.v. administration of enrofloxacin. Paracentesis was performed on the left eye on Days 3 and 4, one hour following enrofloxacin administration, to determine enrofloxacin concentrations in healthy eyes and in eyes with mechanical disruption of the BAB. Paracentesis was also performed on the right eye 23 h after enrofloxacin administration. Blood samples were collected from the horses at identical times to determine enrofloxacin aqueous humour:plasma ratios.Results: Mean ± s.d. enrofloxacin concentration in the aqueous humour one hour post administration on Day 3 was 0.32 ± 0.10 mg/l (range 0.18‐0.47); and aqueous humour enrofloxacin, total protein and aqueous humour:plasma enrofloxacin ratios were higher on Day 4 than Day 3.Conclusions and potential relevance: Following disruption of the BAB, enrofloxacin concentrations were above the reported MIC forLeptospira pomona.
Evaluation of a new strategy to modulate skeletal development in racehorses by imposing track‐based exercise during growth: The effects on 2‐ and 3‐year‐old racing careers
Authors: ROGERS C. W. , FIRTH E. C. , McILWRAITH C. W. , BARNEVELD A. , GOODSHIP A. E. , KAWCAK C. E. , SMITH R. K. W. , van WEEREN P. R. 
Published: February 2008

Summary Reasons for performing study: No data exist on the effects of conditioning exercise at foal age on workload and subsequent clinical injury rate during their 2‐ and 3‐year‐old racing careers. Objectives: To investigate the effects of subjecting TB foals to conditioning exercise prior to the start of race training on: the workload required to reach a level of fitness sufficient to compete; and the prevalence of orthopaedic injury during the first 2 seasons of their racing careers. Methods: Twenty 18‐month‐old TBs, 12 subjected to conditioning exercise at foal age (CONDEX) and 8 exercised spontaneously at pasture only (PASTEX) were trained and entered in competitive events. Workload was quantified using the cumulative workload index (the product of average velocity and distance at a specific gait) and the animals were monitored clinically and radiographically for signs of musculoskeletal disorders. Results: Workload to reach the desired fitness level was similar for CONDEX and PASTEX. CONDEX performed more prerace training sessions as 2‐year‐olds (P<0.05). The incidence of orthopaedic injuries was low in both groups and there were no differences in the occurrence of orthopaedic ailments. PASTEX animals tended to show signs of musculoskeletal disorders earlier than CONDEX animals. This time difference was significant for metacarpophalangeal joint pain on flexion, reduced carpal flexion and hindlimb lameness (P<0.05). Conclusions: Subjecting TB foals to conditioning exercise early in life does not have adverse effects on racing careers at ages 2 and 3 years, and does not influence the workload needed to reach a fitness level that is sufficient for racing. Potential relevance: The lack of negative effects and the indications of some positive effects of early conditioning exercise in the Thoroughbred encourage further large‐scale comparative studies.
Effects of exercise on tenocyte cellularity and tenocyte nuclear morphology in immature and mature equine digital tendons
Authors: STANLEY R. L. , EDWARDS L. J. , GOODSHIP A. E. , FIRTH E. C. , PATTERSON‐KANE J. C. 
Published: February 2008

Summary Reasons for performing study: The injury‐prone, energy‐storing equine superficial digital flexor tendon (SDFT) of the mature performance horse has a limited ability to respond to exercise in contrast with the noninjury‐prone, anatomically opposing common digital extensor tendon (CDET). Previous studies have indicated low levels of cellular activity in the mature SDFT, but in foal tendons the tenocytes may still have the ability to adapt positively to increased exercise. Objectives: To measure tenocyte densities and types in histological sections from the SDFT and CDET of horses from controlled long‐term, short‐term and foal exercise studies. Methods: Specimens were collected from mid‐metacarpal segments of the CDET and SDFT for each horse and processed for histology; central and peripheral regions of the SDFT cross‐section were analysed separately (SDFTc, SDFTp). Tenocyte nuclei were counted in a total area of 1.59 mm2 for each tendon region in each horse. Each nucleus was classified as type 1 (elongate and thin), type 2 (ovoid and plump) or type 3 (chondrocyte‐like); type 1 cells are proposed to be less synthetically active than type 2 cells. Results: No significant differences were noted between exercise and control groups in any of the studies, with the exception of an exercise‐related reduction in the proportion of type 1 tenocytes for all tendons combined in the long‐term study. There were tendon‐ and site‐specific differences in tenocyte densities and proportions of type 1 and 2 cells in all 3 studies. Conclusions and potential relevance: There was no indication that exercise increased tenocyte density or proportions of the (theoretically) more active type 2 cells in immature horses (short‐term and foal studies), perhaps because the training regimens did not achieve certain threshold strain levels. In the foal study these findings can still be interpreted positively as evidence that the training regimen did not induce subclinical damage.