Bead method for measuring the root surface area in conifers

A method of determining the surface area of mycorrhizous conifer roots is described. The roots are cleaned from soil particles by washing, slightly dried and covered with a monolayer of plastic beads. The surface area is estimated on the basis of the weight of adhered beads.The method has been tested against the surface area measurements by a photographic-planimetric method. The estimates of the surface area by both methods compare fairly well.An analysis of model root systems shows that the accuracy of the method for measuring the roots of 0.3mm diameter is about 5%.     

A method for determining the surface area of corals

Although there are several techniques available that can accurately determine the surface area of simple branching corals, there is an absence of techniques that can be applied to finely branching species like Pocillopora damicornis. This paper describes a rapid, spectrophotometer-based technique that can accurately determine the surface area of a range of coral species, including P. damicornis. The technique involves dipping corals coated with plastic varnish into a solution that contains a small amount of detergent and the dye Methylene Blue. The amount of dye solution clinging to the surfaces (as a thinlayer) is proportional to the total surface area.     

New method for determining surface roughness of tongue

doi: 10.1111/j.1741‐2358.2011.00509.x New method for determining surface roughness of tongue Objective: The degree of atrophy of the lingual papillae in elderly individuals was evaluated using a quantitative method. Subjects and methods: One hundred and eighty‐two subjects living in nursing homes and 20 healthy adults as controls were studied. To express the degree of atrophy of the lingual papillae quantitatively, lingual surface roughness was determined by taking an impression with silicone dental material. Based on the impressions obtained from the elderly subjects, they were classified by three expert dentists into three groups: Normal, Smooth and Rough. The same determinations were also performed in the 20 healthy controls and compared with 38 of the elderly subjects who had agreement from all of the experts and without the presence of fissures (Normal, n = 6; Smooth, n = 12; Rough, n = 20). Results: The roughness average value for the controls was 65.0 μm, while that for the elderly subjects in the Normal, Smooth and Rough groups was 73.9 μm, 42.2 μm and 94.1 μm, respectively, which were significantly different. Conclusion: The present results indicate that the present technique of obtaining an impression of the tongue surface is simple and reliable for routine evaluation and quantification of the degree of atrophy as well as morphology of the lingual papillae.     

Measurement of surface area of stones

The surface area of stones can be quickly, accurately, and precisely estimated from linear regression equations of area on a two-dimensional term of the form (xy + yz + zx) where x, y, and z are either the axial dimensions or the axial perimeters of stones. Dimension measurements are made with calipers, and perimeters are measured with a tape measure or a mapping wheel. The best fit slopes for the equations are determined from a representative sample of stones whose surface areas are measured by mapping. Estimates of surface areas of river-worn cobbles by these methods had mean percentage absolute errors of about 4%, considerably better than other methods examined.     

A method to separate plant roots from soil and analyze root surface area

Analysis of the effects of soil management practices on crop production requires knowledge of these effects on plant roots. Much time is required to wash plant roots from soil and separate the living plant roots from organic debris and previous years’ roots. We developed a root washer that can accommodate relatively large soil samples for washing. The root washer has a rotary design and will accommodate up to 24 samples (100 mm diam. by 240 mm long) at one time. We used a flat-bed scanner to digitize an image of the roots from each sample and used a grid system with commercially-available image analysis software to analyze each sample for root surface area. Sensitivity analysis and subsequent comparisons of ‘dirty’ samples containing the roots and all the organic debris contained in the sample and ‘clean’ samples where the organic debris was manually removed from each sample showed that up to 15% of the projected image could be coveredwith debris without affecting accuracy and precision of root surface area measurements. Samples containing a large amount of debris may need to be partitioned into more than one scanning tray to allow accurate measurements of the root surface area. Sample processing time was reduced from 20 h, when hand separation of roots from debris was used, to about 0.5 h, when analyzing the image from an uncleaned sample. The method minimizes the need for preprocessing steps such as dying the roots to get better image contrast for image analysis. Some information, such as root length, root diameter classes and root weights, is not obtained when using this technique. Root length measurements, if needed, could be made by hand on the digital images. Root weight measurement would require sample cleaning and the advantage of less processing time per sample with this method would be lost. The significance of the tradeoff between information not obtained using this technique and the ability to process a greater number of samples with the time and personnel resources available must be determined by the individual researcher and research objectives.     

Normalizing the thermal effects of radiofrequency radiation: body mass versus total body surface area

The current guideline for exposure to radiofrequency radiation (RFR) was developed through assessment of the biological effects data collected primarily from the rat. The consensus that a lack of hazardous biological effects occurred below a whole-body-averaged specific absorption rate (SAR) of 4.0 W/kg led to the proposition of a 0.4 W/kg guideline with a built-in safety factor of 10. This paper demonstrates that if the RFR absorption rate in the rat had been normalized with respect to total body surface area rather than body mass, the exposure guideline would be 2.3 W/m2, which translates to an SAR of approximately 0.06 W/kg for an adult human. It is further shown that a given RFR absorption rate, normalized as a fraction of a species' heat loss per unit of surface area, is independent of body mass over a range of 0.03-100 kg; however, a normalization of the RFR absorption rate to heat loss per unit of body mass is highly dependent on the species' mass. Normalizing the rate of RFR absorption to the surface area of the rat indicates that the current RFR exposure guideline of 0.4 W/kg may be too high.     

城镇化对钱塘江中游支流水质和底栖动物群落结构的影响

于2010年4月调查了浙江省钱塘江中游流域受不同城镇化强度影响的59条1～3级支流的水体理化、底栖动物群落及所在流域的土地利用,分析作为流域城镇化强度指标的不渗水地表面积比(PIA)与溪流水质和生物群落的关系.Spearman秩相关分析表明,TN、NH4+-N、PO43--P、TP、CODMn、电导率、水面宽、水深、细沙淤泥比(％)与PIA呈显著正相关,与林地(％)呈显著负相关.底栖动物指标与PIA的拟合曲线表明它们之间存在显著的非线性关系.其中总分类单元数、Shannon多样性指数、丰富度指数、EPT(％)及捕食者(％)、撕食者(％)、滤食者(％)、刮食者(％)与PIA呈显著负相关,与林地(％)呈显著正相关,但BI指数、集食者(％)、耐污类群(％)、寡毛纲(％)与PIA呈显著正相关.表明研究区域内随着城镇化强度的提高,城镇溪流表现出高氮、磷营养盐水平、物理生境退化、敏感底栖动物物种消失、耐污物种个体数量急剧上升等城镇溪流退化的共性现象.     

The effect of patch disturbance on stream invertebrate community structure: the influence of disturbance history

The effect of disturbance history on the recovery of benthic invertebrate communities following disturbance was investigated in four streams in the Southern Alps of New Zealand. Two of the streams had a history of fluctuating discharge and temperature while the others did not. Recovery from disturbance was tested experimentally using baskets of cobbles, a third of which were disturbed every week for 9 weeks, a further third every 3 weeks and the final third left undisturbed. Algal biiomass, number of invertebrate taxa and total number of invertebrates all declined in baskets disturbed more frequently. Although the relative abundance of some taxa declined with time since the last disturbance, no taxa showed a significant decline in absolute abundance. However, several taxa showed marked increases in relative abundance in the less disturbed treatments particularly at the more stable sites. In contrast to the predictions of ecological theory, numbers of taxa and total invertebrates appeared to recover more quickly in the more complex communities at the stable sites. However, if these communities are considered to represent only stable communities, they do support the view that more complex communities will be more resilient. Community structure at the stable sites was also more similar between baskets in the undisturbed treatment than at the unstable sites, suggesting communities had reached a constant state more quickly. The more rapid recovery of communities measured at the stable sites may have been a consequence of experimental scale; disturbed patches were only 0.045 m² in area and the higher densities of invertebrates at the stable sites meant a larger pool of colonists was available following each experimental disturbance. Nevertheless, ideas of stability in ecological theory and the scale of most spate events suggest this is the appropriate scale for examining community recovery. Furthermore, the larger pool of available colonists could not explain all the differences in community response, as patterns of change in community structure at the stable sites differed considerably more from those expected by purely random colonisation processes than at the unstable sites.     

A rapid method for the estimation of rock surface areas

A method is described for estimating the surface area of irregular-shaped objects, specifically river rocks in the weight range 150–450 g, using a surface coating material and image analysis. The objects are dipped in molten Gelflex®, a PVC resin, which when hardened is peeled off in sections and scanned using a lightbox, camera and appropriate image analysis software. The method is quick, inexpensive, non-destructive, precise and reasonably accurate (within 3.4%) where large numbers of objects are involved.     

Assessing changes in the surface area of the non-cellulose fraction of lignocellulosics

Cholic acid, which preferentially associates with the non- cellulose component of lignocellulosics, is used as a probe to monitor changes in the relative surface area of this fraction of lignocellulosic biomass-to-ethanol substrates. The method is experimentally demonstrated in a traditional enzyme-catalyzed lignocellulosic saccharification experiment.     

The sterologic method of determining the surface area of the mammalian neocortex]

A method for calculation of the square surface area of the cerebral cortex is proposed which represents a combination of the method of averaged reconstruction after a continuous series of histological sections and the stereological method of determination of the length of any curve disposed on the surface. A comparative analysis of the proposed method with curvometrical and stereological (after Hennig's formula) method used earlier for this purpose is made taking as an example the calculation of the neocortex square surface area of some mammals. The results of calculation of the surface by the proposed method were found to coincide with curvometrical data within the range of 5% while the data obtained by stereological method of determination of the absolute square surface area differ from curvometrical data by more than 22%. The proposed method is very convenient and allows considerable acceleration in obtaining results.     

Variation of folded polypeptide surface area with probe size

Three types of polypeptide surface area (contact, accessible, and molecular) have been studied as a function of the radius of a probe sphere used to map the surface. The surfaces are: (1) three alpha-helices, the H-helix of myoglobin, the E-helix of leghemoglobin, and an artificial polyalanine helix, each with 26 residues; (2) two globins, myoglobin and leghemoglobin, each with 153 residues; and (3) a two-center model system for which the three types of surface area have been calculated analytically. The two globin helices have almost identical surface areas as a function of probe size as do the two globins. The polyalanine helix surface area is smaller but similar in shape to the globin helix areas. All three helix contact areas tend to the same limit as the probe size increases, and the globin contact areas behave similarly. Fractal dimensions were calculated for the helix and globin contact and molecular surfaces. All fractal dimensions showed strong dependence on probe size. The contact fractal dimension peaks at larger values for both the helices and globins. Most residues do not make contact with large probes (15 A).     

On the removal and quantification of algal aufwuchs from macrophyte hosts

Accurate population density measurements of algal aufwuchs associated with macrophyte hosts appears to be fraught with uncertainties. This account details a procedure involving aufwuchs removal by agitation and acid hydrolysis with subsequent quantification by a special Sedgwick-Rafter cell counting technique. The aufwuchs removal efficiency from five hosts of widely differing morphology was calculated to be 98.0% (95% confidence limits: 96.3%, 99.7%) after five 45 second agitation cycles.     

A critical examination of four methods of estimating the surface area of stone substrate from streams in relation to sampling Simuliidae (Diptera)

Four methods of calculating stone surface area are examined for their value in estimating simuliid larval density. All methods produced area estimates highly correlated with each other. Stone surface area poorly correlated with simuliid abundance, which we concluded was the result of a highly variable microhabitat and the inability to estimate the surface area actually occupied by larvae. Therefore, if an estimate of stone surface area is required, the simplest methods are sufficient (e.g., maximum length × 90° maximum width).     

利用数码相机和Photoshop软件非破坏性测定叶面积的简便方法

采用数码相机获取叶片的数字图像,用Photoshop图像处理软件计算叶面积,并与目前常用的剪纸法和叶面积仪测定法进行比较分析。结果表明,本方法和上述传统测定方法测定结果存在极显著线性相关;不同拍摄分辨率、单位叶面积存贮像素个数和拍摄角度对测定结果无显著影响。和其它方法相比,本方法具有准确、快速、成本低廉、适合非破坏性动态连续观测等优点,适用于植物生理生态学研究中叶面积的测定。     

一类阔叶树叶面积的通用公式测算法

本文在观察和测算的基础上,提出了一类阔叶树的叶形方程,并对方程进行积分,求出了计算这类阔叶树叶面积的通用公式。从1980年应用至今证明,用这个通用公式计算这类阔叶树的面积,方便、简捷、精度高,现介绍如下。     

A colorimetric method for measuring the surface area of aquatic plants

A procedure is described that allows the determination of the surface area of aquatic plants by dipping them in a surfactant (Liquinox) dye (acridine orange) mixture and measuring the dye retained colimetrically. The method was applied to Vallisneria sp., Elodea canadensis Michx, Potamogeton richardsonii (A. Benn.) Rydb. and Myriophyllum spicatum L. For each species good relationships (0.91 < r² < 0.99) between computed area and dye retention capacity were found.     

A new method for determining cross-sectional shape and area of soft tissues

Assessment of the mechanical properties of soft tissues requires accurate measurement of the cross-sectional area. To date, techniques for determining cross-sectional areas of ligaments and tendons have been less than ideal due to the tissues' complex geometries and the fact that they deform easily under an applied external load. A new procedure has been developed for determining the cross-sectional area by means of an image reconstruction technique based on measurements from collimated laser beams. Using this procedure, the actual shape of the specimen cross-section can also be determined. The results are demonstrated to be highly accurate, and this methodology does not require mechanical contact with the specimen.     

The determination of limestone surface area by linear regression

An accurate procedure is described to determine rapidly and conveniently the surface area of individual pieces of limestone when estimating benthic macroinvertebrate densities. Based on population samples of 60 limestone and 60 traprock fragments, the authors derived r² values in their regressions of volume and weight against surface area of 0.909 and 0.939 and 0.84 and 0.76, respectively. Estimates of limestone surface area by these methods yielded error estimates of 4.2% and 3.6%, equal to or superior to any method reviewed.