scholarly journals A Comparison of the Arithmetic and Geometric Means in Estimating Stump Diameter, Basal Area, and Volume in Appalachian Hardwoods

2007 ◽  
Vol 24 (1) ◽  
pp. 71-73 ◽  
Author(s):  
Harry V. Wiant ◽  
John R. Brooks
Keyword(s):  
Geometric Mean ◽  
Basal Area ◽  
Cross Sectional Area ◽  
Practical Significance ◽  
Sectional Area ◽  
Cross Sectional ◽  
Geometric Means ◽  
The Difference ◽  
Appalachian Hardwoods ◽  
Stump Diameter

Abstract The difference between the use of the arithmetic and geometric means for estimation of average stump diameter, stump cross-sectional area and estimated tree volume was investigated using measurements from 739 stumps from an Appalachian hardwood stand located in central West Virginia. Although average stump diameter, cross-sectional area, and tree volumes were statistically different between estimates based on the arithmetic and geometric mean diameter, these differences were of little practical significance. The difference in average stem diameter, cross-sectional area, tree cubic volume, and board foot volume were 0.05 in, 0.01 ft2, 0.45 ft3, and 2.41 bd ft, respectively.

scholarly journals Comparison of Muscle Cross-sectional Area and Lumbar Muscle Strength According to Degenerative Spinal Diseases

2020 ◽  
Vol 22 (2) ◽  
pp. 1-10
Author(s):  
Ji-Hoon Cho ◽  
Ki-Hyuk Lee ◽  
Seung-Taek Lim ◽  
Buong-O Chun
Keyword(s):  
Muscle Strength ◽  
Cross Sectional Area ◽  
Spinal Diseases ◽  
Sectional Area ◽  
Multifidus Muscle ◽  
Cross Sectional ◽  
Total Group ◽  
Male Group ◽  
The Difference ◽  
Lumbar Extension

OBJECTIVES The purpose of this study was to investigate the difference in the cross - sectional area (CSA) of multifidus and Iliopsoas muscles and the lumbar extension muscle strength according to degenerative spinal diseases (LHI; lumbar herniation of intervertebral disc group, SS; spinal stenosis group, S; spondylolisthesis group).METHODS The CSA of multifidus and Iliopsoas muscles size were measured by PACS(Picture Achiving and Communication System) using MRI at the L4/5 level and lumbar extension muscle strength (72˚, 60˚, 48˚, 36˚, 24˚, 12˚, 0˚) was measured using lumbar extension machine(MedX) in 97 patients of degenerative spinal diseases(male: 57, female: 40). The collected data were analyzed by one-way ANOVA using the SPSS program.RESULTS The results of this study showed that the CSA of total and right multifidus muscle in the LHI was significantly higher than that of the S (p <.05; p <.05) in the male group. The difference between the left and right CSA of multifidus in the LHI group was significantly higher than that of the SS (p <.05) in the male group (p <.05) and total group (p <.05). The CSA of iliopsoas muscle in the S was significantly higher than that of the LHI in the male and total group (p <.05; p <.05). In case of lumbar extension muscle strength, the S showed significantly higher muscle strength at 36 and 48 degrees than that of the SS in the male group. In the total group, LHI showed significantly higher muscle strength at 60 degrees of lumbar extension muscle strength than that of the S.CONCLUSION Multifidus muscle appears to be a key factor in prevention and treatment intervention in low back pain patients. In particular, in the case of S group, exercise therapy for strengthening the multifidus muscle is need for the rehabilitation.

INVESTIGATION OF MAINGATES STABILITY IN STEEP COAL SEAMS AT EXTRACTION LAYOUTS OF DEEP MINE

2020 ◽  
pp. 89-100
Author(s):  
Leonid Bachurin ◽  
◽  
Yuliia Novikova ◽  
Yuliia Simonova ◽  
Vytalyi Dovhal ◽  
...  
Keyword(s):  
Hanging Wall ◽  
Cross Sectional Area ◽  
Practical Significance ◽  
Sectional Area ◽  
Coal Seams ◽  
Cross Sectional ◽  
Deep Mine ◽  
Secondary Support ◽  
The Cross ◽  
Mining Face

Purpose of work. Investigation of maingates stability in different methods of protection on the extraction layouts of a deep coal mine, which develops steeply inclined coal seams. Methods. To achieve this goal, mine experimental observation of maingates stability performed. Conditions for their maintenance are evaluated by the magnitude of the convergence of the side rocks on the contour and changes in the cross-sectional area of the gateroads. Results. As a result of the research the conditions of maingates stability in steep coal seams in protection by pillars or timber sets are substantiated. It is recorded that in the zone of influence of extraction operations, at a distance of l <60 m behind the mining face with the considered methods of protection, the support of the maingates is deformed within the yielding limits and has characteristic flexures the side of hanging wall. At a distance of l≥60 m, the cross-sectional area of the maingates is reduced to 50% of the initial values, and the amount of roof to floor convergence exceeds the flexibility of the support. The increase displacement of rock mass on the contour of the supported roadway behind the mining face depends on the strength and geometry of the secondary support structures above the maingate. Novelty. It is experimentally established that the change in the cross-sectional area of the maingate during protection by timber sets occurs linearly with increasing length of the extraction layout. Practical significance. To ensure the maingates stability, it is advisable to use non-pillar methods of protection, when using yielding secondary support systemsabove the roadway, or backfilling.

Maintenance of myonuclear domain size in rat soleus after overload and growth hormone/IGF-I treatment

1998 ◽  
Vol 84 (4) ◽  
pp. 1407-1412 ◽  
Author(s):  
G. E. McCall ◽  
D. L. Allen ◽  
J. K. Linderman ◽  
R. E. Grindeland ◽  
R. R. Roy ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Domain Size ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Muscle Weight ◽  
Cross Sectional ◽  
Igf I ◽  
Myonuclear Domain ◽  
The Difference ◽  
Saline Vehicle

The purpose of this study was to determine the effects of functional overload (FO) combined with growth hormone/insulin-like growth factor I (GH/IGF-I) administration on myonuclear number and domain size in rat soleus muscle fibers. Adult female rats underwent bilateral ablation of the plantaris and gastrocnemius muscles and, after 7 days of recovery, were injected three times daily for 14 days with GH/IGF-I (1 mg/kg each; FO + GH/IGF-I group) or saline vehicle (FO group). Intact rats receiving saline vehicle served as controls (Con group). Muscle wet weight was 32% greater in the FO than in the Con group: 162 ± 8 vs. 123 ± 16 mg. Muscle weight in the FO + GH/IGF-I group (196 ± 14 mg) was 59 and 21% larger than in the Con and FO groups, respectively. Mean soleus fiber cross-sectional area of the FO + GH/IGF-I group (2,826 ± 445 μm2) was increased compared with the Con (2,044 ± 108 μm2) and FO (2,267 ± 301 μm2) groups. The difference in fiber size between the FO and Con groups was not significant. Mean myonuclear number increased in FO (187 ± 15 myonuclei/mm) and FO + GH/IGF-I (217 ± 23 myonuclei/mm) rats compared with Con (155 ± 12 myonuclei/mm) rats, although the difference between FO and FO + GH/IGF-I animals was not significant. The mean cytoplasmic volume per myonucleus (myonuclear domain) was similar across groups. These results demonstrate that the larger mean muscle weight and fiber cross-sectional area occurred when FO was combined with GH/IGF-I administration and that myonuclear number increased concomitantly with fiber volume. Thus there appears to be some mechanism(s) that maintains the myonuclear domain when a fiber hypertrophies.

scholarly journals Use of computer-assisted analysis for myofiber size measurements of rat soleus muscles from photographed images.

1994 ◽  
Vol 42 (3) ◽  
pp. 377-382 ◽  
Author(s):  
G R Miller ◽  
W T Stauber
Keyword(s):  
Cross Sectional Area ◽  
Area Measurement ◽  
Practical Significance ◽  
Computer Assisted ◽  
Sectional Area ◽  
Image Capture ◽  
Cross Sectional ◽  
Atrophic Muscle ◽  
Reproducible Method ◽  
Assisted Analysis

Since myofiber cross-sectional area measurements are important in describing myofiber adaptations to physiological and pathological changes, we developed a reproducible method for measuring myofiber size using fluorescent stains. Several 35-mm slides of dystrophin-, laminin-, and concanavalin A (ConA)-stained muscle sections were used to calculate myofiber cross-sectional areas and to compare different techniques and settings of an image capture system. Although variation in equipment settings did result in variation in myofiber area, the overall effect was of little practical significance (< 6%). Using midrange values for the settings of illumination, black level, and gain, reproducible quantitative data were collected and analyzed from 35-mm slides of FITC-labeled conA taken from atrophic, normal, and hypertrophic muscle samples. As expected, the atrophic muscle fibers were smaller. However, in hypertrophic muscle from compensatory overload, the fibers were composed of both large and small fibers. We found it important that the myofiber cross-sectional area measurements be expressed both in terms of average fiber areas and as frequency distribution histograms. In addition, detailed methodology of fiber area measurement must be provided.

scholarly journals Comparison of the Arithmetic and Geometric Means in Estimating Crown Diameter and Crown Cross-Sectional Area

2010 ◽  
Vol 34 (4) ◽  
pp. 186-189
Author(s):  
KaDonna C. Randolph
Keyword(s):  
Arithmetic Mean ◽  
Cross Sectional Area ◽  
Practical Significance ◽  
Sectional Area ◽  
Average Difference ◽  
Arithmetic Means ◽  
Cross Sectional ◽  
Absolute Value ◽  
Crown Diameter ◽  
The Mean

Abstract The use of the geometric and arithmetic means for estimating tree crown diameter and crown cross-sectional area were examined for trees with crown width measurements taken at the widest point of the crown and perpendicular to the widest point of the crown. The average difference between the geometric and arithmetic mean crown diameters was less than 0.2 ft in absolute value. The mean difference between crown cross-sectional areas based on the geometric and arithmetic mean crown diameters was less than 6.0 ft2 in absolute value. At the plot level, the average difference between cumulative crown cross-sectional areas based on the geometric and arithmetic mean crown diameters amounted to less than 2.5% of the total plot area. The practical significance of these differences will depend on the final application in which the mean crown diameters are used.

scholarly journals On a method of determining the viscosity of gases, especially those available only in small quantities

1910 ◽  
Vol 83 (562) ◽  
pp. 265-276 ◽  
Keyword(s):  
Volume Content ◽  
Capillary Tube ◽  
Cross Sectional Area ◽  
The Other ◽  
Sectional Area ◽  
Cross Sectional ◽  
Fine Capillary ◽  
The Difference ◽  
Absolute Measurements ◽  
Unlimited Amount

The apparatus about to be described was designed for the purpose of comparing the viscosities of neon, xenon, and krypton—the loan of which Sir William Ramsay kindly offered the author—with that of air. With such small quantities of gas available, the volume content of the apparatus must obviously be correspondingly small, and therefore, it would seem, unsuitable for absolute measurements. The object of the present paper is to show that this is by no means the case. As will be seen later, the method is actually restricted to small quantities by the conditions of the experiments, but there is no reason why it should not be used even when the gas under test may be obtained in practically unlimited amount. Theory of the Method . Consider a closed glass vessel (as in fig. 1) consisting of two connected limbs, one a fine capillary tube and the other of much greater cross-sectional area, yet sufficiently narrow for a pellet of mercury to remain intact in it. Let V be the volume unoccupied by mercury (the volume of the capillary tube being considered negligible). Let P denote the steady pressure of the gas in the tube when the latter is held horizontally, and let p be the difference of pressure caused by the mercury pellet when the apparatus is vertical. Let p 1 be the pressure and v 1 the volume at any time above the mercury, and p 2 , v 2 , the corresponding quantities below the mercury. Then V = v 1 + v 2 , and p 2 - p 1 = p .

The Skeleton of Giraffes

2021 ◽  
pp. 342-381
Author(s):  
Graham Mitchell
Keyword(s):  
Cervical Vertebrae ◽  
Lumbar Vertebrae ◽  
Average Density ◽  
Cross Sectional Area ◽  
Thoracic Vertebrae ◽  
Sectional Area ◽  
Average Chemical Composition ◽  
Cross Sectional ◽  
Limb Bones ◽  
The Difference

The giraffe skeleton consists of ~170 bones. The dry mass of the skeleton is 70 g.kg-1 body mass. The average chemical composition of their bones is 33% minerals (mainly calcium and phosphorus in a ratio of 2:1), 34% collagen, and 33% water. The skull contributes ~10%, the vertebrae ~25% and the limb bones ~65% to skeleton mass. The average density of all bones is 1.6 g cm-3, ranging from 0.8 g cm-3 (cervical vertebrae) to 2.0 g cm-3 (limb bones). Resistance to fracture by vertebrae depends on their cross-sectional area, and is greatest in cervical and the first few thoracic vertebrae. Resistance to fracture by limb bones depends on wall thickness (the difference between inner and outer diameter), which is uniquely thick. The growth of all limb bones except the humerus follows a geometric pattern (length and diameter increase at the same rate) which confers resistance to compression stress. The humerus follows an elastic pattern (diameter increases faster than length) a pattern that resists bending stress. Giraffes bones are exceptionally straight which further reduces bending stresses. The torque generated by the mass of the head and neck is resisted by the ligamentum nuchae which is exceptionally well-developed in giraffes, extends from the lumbar vertebrae to the occipital crest, can have a diameter of ~10 cm, and can support loads of ~1.8 tonnes before rupturing. As a giraffe grows muscle cross-sectional area (and contraction strength) declines and the duty factor reduces, both of which reduce the risk of fracture.

An antithetic variate to facilitate upper-stem height measurements for critical height sampling with importance sampling

2013 ◽  
Vol 43 (12) ◽  
pp. 1151-1161 ◽  
Author(s):  
Thomas B. Lynch ◽  
Jeffrey H. Gove
Keyword(s):  
Importance Sampling ◽  
Basal Area ◽  
Cross Sectional Area ◽  
Sample Point ◽  
Sectional Area ◽  
Critical Height ◽  
Cross Sectional ◽  
Individual Tree ◽  
Sample Tree ◽  
The Cross

Critical height sampling (CHS) estimates cubic volume per unit area by multiplying the sum of critical heights measured on trees tallied in a horizontal point sample (HPS) by the HPS basal area factor. One of the barriers to practical application of CHS is the fact that trees near the field location of the point-sampling sample point have critical heights that occur quite high on the stem, making them difficult to view from the sample point. To surmount this difficulty, use of the “antithetic variate” associated with the critical height together with importance sampling from the cylindrical shells integral is proposed. This antithetic variate will be u = (1 − b/B), where b is the cross-sectional area at “borderline” condition and B is the tree’s basal area. The cross-sectional area at borderline condition b can be determined with knowledge of the HPS gauge angle by measuring the distance to the sample tree. When the antithetic variate u is used in importance sampling, the upper-stem measurement will be low on tree stems close to the sample point and high on tree stems distant from the sample point, enhancing visibility and ease of measurement from the sample point. Computer simulations compared HPS, CHS, CHS with importance sampling (ICHS), ICHS and an antithetic variate (AICHS), and CHS with paired antithetic varariates (PAICHS) and found that HPS, ICHS, AICHS, and PAICHS were very nearly equally precise and were more precise than CHS. These results are favorable to AICHS, since it should require less time than either PAICHS or ICHS and is not subject to individual-tree volume equation bias.

scholarly journals The comparative study of analyzing the T-shaped and square-shaped concrete columns

2021 ◽  
Vol 331 ◽  
pp. 05005
Author(s):  
Ade Sri Wahyuni ◽  
Mukhlis Islam ◽  
Rizky Arian Putra
Keyword(s):  
Concrete Columns ◽  
Cross Sectional Area ◽  
Shape Effect ◽  
Strain Diagram ◽  
Sectional Area ◽  
Cross Sectional ◽  
Three Samples ◽  
The Difference ◽  
The Comparative Study ◽  
Calculation Analysis

This study aims to analyze how much changes in column shape effect have on the strength of the column structure. This calculation is comparing a square-shaped concrete column with two different axis of a T-shaped column. Each sample is compared in terms of 6 different column dimensions, however, the cross-sectional area within the three samples ( Square, T-shaped axis1 and 2) has remained constant. The concrete quality (fc') is kept at 30 MPa while the reinforcement area used 1% and 5%. Column calculation analysis is using Hognestad stress-strain diagram relationship and finite difference method. The result shows, the greater the reinforcement ratio, the greater the difference of Mn value and the smaller the difference of Pn value, of T-shaped and square column for each area. The same cross-sectional area does not necessarily lead to the same behavior of a T-shaped column with a different axis

scholarly journals (323) Alternate Approaches for Evaluating Horticultural Efficiency

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1038C-1038
Author(s):  
Timothy L. Righetti ◽  
Carmo Vasconcelos ◽  
David R. Sandrock ◽  
Samuel Ortega ◽  
Yerko Moreno
Keyword(s):  
Leaf Area ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Improvement Potential ◽  
Canopy Area ◽  
Alternate Assessments ◽  
Physiological Differences ◽  
The Difference ◽  
The Relationship

Four ratio-based efficiency expressions (yield/trunk cross-sectional area, yield/canopy area, yield/pruning weight, CO2 assimilation/leaf area) were evaluated. These expressions depend on the size of the denominator if the function describing the relationship between the denominator and the numerator has a non-zero intercept. When this occurs, it is difficult to determine if statistically different efficiency expressions reflect physiological differences or are caused by comparing expressions with different sized denominators. When denominators and numerators of efficiency expressions are plotted, the edge of the data cloud can often be statistically identified. The function describing the edge of the data cloud defines the maximum possible value (MPV) obtainable for a given value of the denominator. The percentage of MPV (%MPV) is an alternate efficiency expression that is not influenced by differing trunk cross-sectional area, canopy area, pruning weight, or leaf area. The difference between MPV and observed performance can be used to define improvement potential (IP). These alternate assessments can supplement traditional efficiency expressions. It is also possible to determine if statistical differences in traditional efficiency expressions are caused by differences in potential, differences in a plant or leaf's ability to achieve its potential, or differences in the size of the efficiency expression denominators.

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