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Diameter Greater (diameter + greater)
Selected AbstractsGeomorphic and riparian forest influences on characteristics of large wood and large-wood jams in old-growth and second-growth forests in Northern Michigan, USAEARTH SURFACE PROCESSES AND LANDFORMS, Issue 8 2007Arthur E. L. Morris Abstract Large wood (LW; pieces with diameter greater than 10 cm and length greater than 1 m) and large-wood jams (LWJs; two or more pieces of LW in contact with each other) are important components of stream ecosystems that are often distributed along stream channels in response to geomorphic and riparian forest factors that interact hierarchically. As a result, information on these relationships is valuable for predicting patterns of wood accumulation and characteristics of individual pieces of wood. We studied relationships between geomorphic and riparian factors and LW and LWJ structure in different geomorphic settings associated with old-growth and second-growth settings in Upper Michigan. We used redundancy analysis (RDA) and regression tree analysis to evaluate changes in LW and LWJ structural characteristics among geomorphic and riparian forest settings. Geomorphic factors explained 38·5% of the variability in LW and LWJ characteristics, riparian forest factors uniquely explained 18·4% of the variance and the intersection of the two categories of environmental factors (i.e. the redundant portion) was 29·8%. At the landscape scale, our multivariate analyses suggest that the presence of rock-plane bedding was an important predictor of the number of LWJs and the percent of channel spanned by LWJs. Our analyses suggest differences in relationships between geomorphic factors and LW and LWJ structure. Channel width, distance from headwaters, gradient and sinuosity were identified by regression tree analyses as the most important variables for predicting LW characteristics, while channel width and confinement were the most important variables for predicting LWJ characteristics. Old-growth settings generally contained a higher proportion of conifer and LW (both in and out of LWJs) with greater diameter and volume than in second-growth settings. Our study supports the view that restoration of wood to streams will benefit from considering the associations of wood structure with landscape and reach-scale geomorphology. Copyright © 2007 John Wiley & Sons, Ltd. [source] Prospective Study of Accuracy and Outcome of Emergency Ultrasound for Abdominal Aortic Aneurysm over Two YearsACADEMIC EMERGENCY MEDICINE, Issue 8 2003Vivek S. Tayal MD Abstract Determination of the presence of an abdominal aortic aneurysm (AAA) is essential in the management of the symptomatic emergency department (ED) patient. Objectives: To identify whether emergency ultrasound of the abdominal aorta (EUS-AA) by emergency physicians could accurately determine the presence of AAA and guide ED disposition. Methods: This was a prospective, observational study at an urban ED with more than 100,000 annual patient visits with consecutive patients enrolled over a two-year period. All patients suspected to have AAA underwent standard ED evaluation consisting of EUS-AA, followed by a confirmatory imaging study or laparotomy. AAA was defined as any measured diameter greater than 3 cm. Demographic data, results of confirmatory testing, and patient outcome were collected by retrospective review. Results: A total of 125 patients had EUS-AA performed over a two-year period. The patient population had the following characteristics: average age 66 years, male 54%, hypertension 56%, coronary artery disease 39%, diabetes 22%, and peripheral vascular disease 14%. Confirmatory tests included radiology ultrasound, 28/125 (22%); abdominal computed tomography, 95/125 (76%); abdominal magnetic resonance imaging, 1/125 (1%); and laparotomy, 1/125 (1%). AAA was diagnosed in 29/125 (23%); of those, 27/29 patients had AAA on confirmatory testing. EUS-AA had 100% sensitivity (95% CI = 89.5 to 100), 98% specificity (95% CI = 92.8 to 99.8), 93% positive predictive value (27/29), and 100% negative predictive value (96/96). Admission rate for the study group overall was 70%. Immediate operative management was considered in 17 of 27 (63%) patients with AAA; ten patients were taken to the operating room. Conclusions: EUS-AA in a symptomatic population for AAA is sensitive and specific. These data suggest that the presence of AAA on EUS-AA should guide urgent consultation. Emergency physicians were able to exclude AAA regardless of disposition from the ED. [source] Handheld ultrasound device for detection of non-opaque and semi-opaque foreign bodies in soft tissues,JOURNAL OF CLINICAL ULTRASOUND, Issue 4 2003Angela D. Levy MD Abstract Purpose The aim of this study was to determine whether a portable handheld ultrasound device can be used to visualize non-opaque and semi-opaque foreign bodies in soft tissues and to characterize their sonographic appearance. Methods Twenty-two fragments composed of various natural and man-made materials and ranging from 4 to 20 mm in the maximum longitudinal dimension were embedded into 2 thawed turkey breasts. Two sonographers who were unaware of the number, dimensions, and locations of the fragments used a handheld ultrasound device to detect and characterize the fragments on the basis of their surface echogenicity and acoustic shadowing. The sonographic appearance of each fragment was compared with its actual characteristics. Results All 22 embedded fragments were successfully identified and localized on sonography. Surface echogenicity and acoustic shadowing varied among the fragments. For some fragments, the sonographically measured maximum longitudinal dimension differed substantially from the actual dimension. Conclusions Use of a portable handheld ultrasound device is effective for the detection of foreign bodies with a diameter greater than 4 mm in soft tissues. The sonographic appearances of non-opaque and semi-opaque foreign bodies vary in their patterns of surface echogenicity and acoustic shadowing. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:183,188, 2003 [source] Brittle-Ductile Transitions in Sucrose and the Influence of Lateral Stresses During CompactionJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 2 2000R. J. ROBERTS Sucrose, in a range of particle sizes, has been compacted to investigate both the effect of brittle-ductile transition and the effect of lateral stresses on the deformation stress as measured using Heckel plots. All particles with a diameter greater than 30 ,m exhibited cracking in line with both theoretical predictions and literature data from hammer and ball milling. In addition, crack lengths in compressed particles examined microscopically were very similar to those predicted from the deformation stress, confirming the applicability of the model. [source] Reversal of Atrial Remodeling after Cardioversion of Persistent Atrial Fibrillation Measured with MagnetocardiographyPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2 2009MIKA LEHTO M.D. Background: Atrial fibrillation (AF) causes electrical, functional, and structural changes in the atria. We examined electrophysiologic remodeling caused by AF and its reversal noninvasively by applying a new atrial signal analysis based on magnetocardiography (MCG). Methods: In 26 patients with persistent AF, MCG, signal-averaged electrocardiography (SAECG), and echocardiography were performed immediately after electrical cardioversion (CV), and repeated after 1 month in 15 patients who remained in sinus rhythm (SR). Twenty-four matched subjects without history of AF served as controls. P-wave duration (Pd) and dispersion (standard deviation of Pd values in individual channels) and root mean square amplitudes of the P wave over the last 40 ms portions (RMS40) were determined. Results: In MCG Pd was longer (122.8 ± 18.2 ms vs 101.5 ± 14.6 ms, P < 0.01) and RMS40 was higher (60.4 ± 28.2 vs 46.9 ± 19.1 fT) in AF patients immediately after CV as compared to the controls. In SAECG Pd dispersion was increased in AF patients. Mitral A-wave velocity and left atrial (LA) contraction were decreased and LA diameter was increased (all P < 0.01). After 1 month, Pd in MCG still remained longer and LA diameter greater (both P < 0.05), while RMS40 in MCG, Pd dispersion in SAECG, mitral A-wave velocity, and LA contraction were recovered. Conclusions: Magnetocardiographically detected atrial electrophysiologic alterations in persistent AF diminish rapidly although incompletely during maintained SR after CV. This might be related to the known early high and late lower, but still existent tendency to AF relapses. [source] Posterior fossa malformation in fetuses: a report of 56 further cases and a review of the literaturePRENATAL DIAGNOSIS, Issue 6 2007F. Forzano Abstract Objective The purposes of this study were to determine the outcome of fetuses diagnosed as having a posterior fossa abnormality (PFA) and to find out if there are associated features helpful in determining the prognosis. Methods This is a retrospective study of all posterior fossa abnormalities detected prenatally in our Units within the last 10 years. Fifty six patients were selected. Outcome data was collected from the Clinical Genetics Department records and the attending obstetrician or pediatrician. Results An enlarged cisterna magna (ECM, diameter greater than 10 mm at 18,23 gw) was detected in 22 fetuses, which was isolated in 14 cases. All the patients followed-up (n = 11) with isolated ECM were normal at birth (100%). Non-isolated ECM was present in 8 cases. Further information was available in 7, 5 (71%) of whom had a poor outcome. A Dandy Walker complex abnormality (DWC) was detected in 34 patients. The majority of them had a poor prognosis, 54% if isolated and 84% if non-isolated. Conclusions Isolated ECM detected on prenatal scans has a favourable outcome, while DWC is associated with a very high chance of a poor prognosis. Copyright © 2007 John Wiley & Sons, Ltd. [source] Allometry and biomass distribution in replanted mangrove plantations at Gazi Bay, KenyaAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue S1 2009J. G. Kairo Abstract 1.This study reports above-ground biomass of 5 and 8 years old mangrove plantations in Kenya. Trees with stem diameter greater than 5.0,cm inside 100,m2 sample plots were harvested, and then separated into stems (trunks), branches, leaves and prop roots. 2.Mean above-ground biomass was calculated at 20.25 t dry matter ha,1 for Rhizophora mucronata Lam., 11.7 t dry matter ha,1 for Avicennia marina (Forsk.) Vierh., 6.7 t dry matter ha,1 for Sonneratia alba Sm. and 3.7 t dry matter ha,1 for Ceriops tagal (Perr.) C. B. Robinson. In A. marina and R. mucronata, stems (52.19%) and prop-roots (30.28%), respectively, accounted for the highest proportion of the above-ground dry weight. While in S. alba and C. tagal, branch biomass represented the highest percentage of biomass, 48.20% and 43.62%, respectively. 3.The total above-ground biomass of R. mucronata was best estimated from regression equations using a combination of height and diameter above stilt root as the independent variables. For A. marina, C. tagal and S. alba there was no simple correlation found between the above-ground biomass and tree height or stem diameter. 4.Comparison of the regression models with those developed elsewhere gave different biomass values in these plots, further reinforcing the need for the use of site-specific allometric equations for biomass estimation. Copyright © 2009 John Wiley & Sons, Ltd. [source] Axillary staging during surgery for breast cancerBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 3 2007C. K. Axelsson Background: Axillary lymph node status remains the single most important prognostic parameter in patients with breast cancer. In approximately half of operations sentinel lymph node biopsy cannot be employed and axillary dissection is indicated. Retrieval of ten nodes has hitherto been considered sufficient, but it remains questionable whether the removal of more lymph nodes might improve staging. Methods: Data from 31 679 breast cancer operations in Denmark were analysed. Results: The number of axillary lymph nodes retrieved was an independent and strong predictor of node positivity. The more lymph nodes retrieved, the better the staging of the disease; this was evident for all sizes of tumour. Dissection of 20 or more nodes rather than ten to 14 increased the probability of node positivity from 14·2 to 25·9 per cent for 1,5-mm tumours, from 38·6 to 47·9 per cent for 11,20-mm tumours, and from 80·6 to 90·0 per cent for tumours with diameter greater than 50 mm. Conclusion: The number of metastatic lymph nodes increased as more nodes were retrieved. These findings underline the need for high-quality specialist surgical and pathological services in breast cancer treatment. Copyright © 2007 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source] A single ultrasonographic scan at age 65 years excludes 95 per cent of men from future aneurysm riskBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 4 2001P. Crow Background: In 1988, 236 men, then aged 65 or 66 years, underwent an abdominal ultrasonographic scan as part of a pilot study for an aneurysm screening programme; 223 (95 per cent) had an aortic diameter of 25 mm or less, and form the main study group. Methods: This group was followed with repeat ultrasonography in 1993 and 2000. Eight men (4 per cent) were lost to follow-up or refused further scanning, but all are known to be still alive. Eighty-six men (39 per cent) died during the 12-year follow-up. Causes of death were investigated. None was related to abdominal aortic aneurysm (AAA). Some 129 men (58 per cent) had all three ultrasonographic scans, including some arranged in other hospitals or performed with a portable scanner at a home visit. Mean(s.e.m.) aortic diameter for this group was 18·9(2·3) mm in 1988, 19·0(2·6) mm in 1993 and 20·2(3·8) mm in 2000. Results: At the scan in 2000, four men had an aortic diameter greater than 30 mm (32, 34, 34 and 36 mm respectively). In contrast, of the 13 men with an aortic diameter greater than 25 mm in 1988, three have undergone elective aneurysm repair, eight have died from causes unrelated to AAA and two remain under ultrasonographic surveillance. Conclusion: Using an aortic diameter threshold of 25 mm, a single ultrasonographic scan at the age of 65 years is able to exclude 95 per cent of men who appear extremely unlikely ever to develop a clinically significant aortic aneurysm and to identify the 5 per cent who require further follow-up. © 2001 British Journal of Surgery Society Ltd [source] A biomechanical study on flexible intramedullary nails used to treat pediatric femoral fracturesJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 6 2005Jason K. Green Abstract Flexible intramedullary nails have been indicated to treat femoral fractures in pediatric patients. The purpose of this study was to examine the stability of simulated transverse fractures after retrograde intramedullary flexible nail fixation. Various nail diameter combinations were tested using composite femurs in bending, torsion, and a combined axial/bending test where a vertical compressive force was applied to the femoral head. The cross-sectional percent area fill of the nails within the femurs was also determined. In 4 point bending, the greatest repair stiffness was 12% of the intact stiffness. In torsion, the greatest stiffness was 1% of the intact stiffness for either internal or external rotation. The greatest repair stiffness was 80% of the intact stiffness for a compressive load applied to the femoral head. Nail combinations with single nail diameters greater than 40% of the mid-shaft canal width, as measured from an AP radiograph, prevented the fracture from being reduced and left a posterior gap. Flexible intramedullary nails may be of value in the treatment of pediatric femoral fractures, but care must be taken to insert nails that are correctly sized for the canal and to protect the healing fracture from high torsional and bending loads. © 2005 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] | |||||||||||||