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1.
香菇Lentinula edodes质地是影响其食味品质和货架期的一系列重要品质指标.本研究首次基于质构仪质地多面分析法(TPA),结合传统感官评级对ZX6(浙香6号)和Lsm9两个香菇亲本及其2个杂交菌株(L1*11和L4*6)子实体的不同部位(菌柄P1、菌盖顶部P2、菌盖中心P3和菌盖侧边P4)的7个质地指标和2个...  相似文献   

2.
Forum     
Bioturbate texture is still the venerable senior synonym of ‘ichno‐fabric’  相似文献   

3.
The occurrence of selected plant-parasitic nematodes in the hemlock-hardwood-white pine, boreal forest, tundra, and oak-hickory associations in some northern states was compared. Helicotylenchus platyurus and Xiphinema americanum were not found in the boreal forest and tundra, and occurred infrequently in the hemlock-hardwood-white pine areas. They were found frequently, however, in the oak-hickory forest of Iowa. It is questioned that vegetational differences among the areas account directly for the major differences in nematode occurrence. Presence and absence of nematodes and their numbers in the oak-hickory association were clustered by similarity coefficients by sites and correlated with soil pH, percentage organic matter, percentage sand-silt-clay, and field capacity. Of the soil factors measured, pH gave the strongest correlations with nematode numbers. Xiphinema chambersi was found only in soils with a pH between 4.5 and 6.4 while the largest numbers of H. platyurus, H. pseudorobustus, and X. americanum occurred in soil above pH 6.0.  相似文献   

4.
Why do the equally spaced dots in figure 1 appear regularly spaced? The answer ‘because they are’ is naive and ignores the existence of sensory noise, which is known to limit the accuracy of positional localization. Actually, all the dots in figure 1 have been physically perturbed, but in the case of the apparently regular patterns to an extent that is below threshold for reliable detection. Only when retinal pathology causes severe distortions do regular grids appear perturbed. Here, we present evidence that low-level sensory noise does indeed corrupt the encoding of relative spatial position, and limits the accuracy with which observers can detect real distortions. The noise is equivalent to a Gaussian random variable with a standard deviation of approximately 5 per cent of the inter-element spacing. The just-noticeable difference in positional distortion between two patterns is smallest when neither of them is perfectly regular. The computation of variance is statistically inefficient, typically using only five or six of the available dots.  相似文献   

5.
Measuring the fine-scale heterogeneity of stones and other substrates is a challenge for benthic ecologists. I describe a method for measuring the roughness of stones that is based on the ratio of two surface area measurements: one that follows substrate contours and one based on a similar-sized modified spheroid. This roughness index is easily measured, assesses the entire surface of stones, and enables the measurement of replicate stones. Roughness measurements of 14 rock types demonstrated that values obtained were consistent with perceived roughness and porosity. Application of the roughness index to a published data set produced a curvilinear relationship between stone roughness and the biomass of algae in roughness-associated crevices.  相似文献   

6.
The movement of water from moist to dry soil layers through the root systems of plants, referred to as hydraulic redistribution (HR), occurs throughout the world and is thought to influence carbon and water budgets and ecosystem functioning. The realized hydrologic, biogeochemical and ecological consequences of HR depend on the amount of redistributed water, whereas the ability to assess these impacts requires models that correctly capture HR magnitude and timing. Using several soil types and two ecotypes of sunflower (Helianthus annuus L.) in split‐pot experiments, we examined how well the widely used HR modelling formulation developed by Ryel et al. matched experimental determination of HR across a range of water potential driving gradients. H. annuus carries out extensive night‐time transpiration, and although over the last decade it has become more widely recognized that night‐time transpiration occurs in multiple species and many ecosystems, the original Ryel et al. formulation does not include the effect of night‐time transpiration on HR. We developed and added a representation of night‐time transpiration into the formulation, and only then was the model able to capture the dynamics and magnitude of HR we observed as soils dried and night‐time stomatal behaviour changed, both influencing HR.  相似文献   

7.
Abstract

Purpose: Skin contributes to joint position sense (JPS) at multiple joints. Altered cutaneous input at the foot can modulate gait and balance and kinesiology tape can enhance proprioception at the knee, but its effect may be dependent on existing capacity. The effect of texture at the knee, particularly in those with poor proprioception, is unknown. The aim of this study was to determine the effect of textured panels on JPS about the knee.

Materials and methods: Eighteen healthy females were seated in an adjustable chair. Their left leg (target limb) moved passively from 65° to a target of flexion (115° or 90°) or extension (40°). Their right leg (matching limb) was passively moved towards this target angle and participants indicated when their limbs felt aligned. We tested three textured panels over the knee of the matching limb and two control conditions. The target limb maintained a control panel. Directional error, absolute error and variable error in matching between limbs were calculated.

Results: On average textured panels over the knee increased JPS error compared to control pants for participants with poor JPS. These participants undershot the target at 90° of flexion significantly more with textured panels (?11°?±?3°) versus control (?7°?±?3°, p?=?0.04).

Conclusions: For participants with poor JPS accuracy, increased JPS error at 90° with a textured panel suggests these individuals utilised altered cutaneous information to adjust joint position. We propose increased error results from enhanced skin input at the knee leading to the perception of increased flexion.  相似文献   

8.
本文探讨了牙周病摄片数字化分析,即纹理分析技术,应用于牙周病诊断的可能性。数字化分析能提供牙槽骨图象的细部特征特征描述和定量表达的形式,将为牙周病提供一种新的诊断方法。  相似文献   

9.
It has been suggested that numerosity is an elementary quality of perception, similar to colour. If so (and despite considerable investigation), its mechanism remains unknown. Here, we show that observers require on average a massive difference of approximately 40% to detect a change in the number of objects that vary irrelevantly in blur, contrast and spatial separation, and that some naive observers require even more than this. We suggest that relative numerosity is a type of texture discrimination and that a simple model computing the contrast energy at fine spatial scales in the image can perform at least as well as human observers. Like some human observers, this mechanism finds it harder to discriminate relative numerosity in two patterns with different degrees of blur, but it still outpaces the human. We propose energy discrimination as a benchmark model against which more complex models and new data can be tested.  相似文献   

10.
梨果实肉质遗传模式的探讨   总被引:5,自引:0,他引:5  
根据3种类型梨杂交组合后代的遗传表现,提出梨果实肉质遗传模式为:梨果实肉质的脆软肉遗传为质量性状遗传,由A、B两对基因控制。软肉对脆肉为显性,只有两对基因同时隐性纯合时才表现为脆肉。脆肉基因型为aa bb,软肉基因型为A_ _ _、_ _B_,该模式可解释前人的部分研究成果。 Abstract:The crispness and softness of flesh texture in pear are qualitative characters,controlled by two genes A,B.The softness is dominant to crispness,only when two genes are recessive homozygous,the phenotype is crispness.The genotype of crispness is aabb,the genotypes of softness are A_ _ _,_ _ B_,Some factors may affect flesh also.  相似文献   

11.
Longidorus breviannulatus n. sp. was associated with stunted corn in Iowa. The nematode has wide bilobed amphidial pouches, a guiding ring 21-26 μm from the anterior end of the body, an odontostyle 81-88 μm long, and a spear extension 28-45 μm long. The most frequent collections and the greatest numbers of the nematode in the field occurred in sandy soils. Nematodes increased in greenhouse culture from an initial population of 100 to 4,120 individuals in 322 days.  相似文献   

12.
该研究以12个葡萄品种成熟期果实为材料,采用质地剖面分析(TAP)法测定其果肉硬度、弹性、黏着度、胶着度、咀嚼性和回复性等TAP质构参数,对其果实口感质地进行分级评价;测定葡萄果肉细胞壁组成物质(水溶性果胶、原果胶、纤维素)的含量以及PG、PEP、PL、CE等关键酶活性;采用组织切片法观察了葡萄果肉组织细胞的显微结构,测定其细胞面积、周长、长度、宽度等细胞结构参数和纵横比、圆度等细胞形状参数,以探讨各指标在不同品种间的差异以及细胞壁组成物质、关键酶活性和细胞形态参数与果肉质地的关系,为葡萄果肉质地品质调控提供依据。结果显示:(1)12个葡萄品种果实果肉可评为脆、酥脆、硬、中等、软5种口感质地类型等级。(2)葡萄果实质构参数以及果肉细胞壁组成物质含量、关键酶活性、细胞形态参数和显微结构在各质地类型品种间存在明显差异;质构参数中果实去皮TPA硬度、胶着度和咀嚼性等指标差异最大,变异系数分别达到75.16%、65.57%和65.25%;细胞壁组成物质及关键酶活性指标中纤维素含量及水溶性果胶/原果胶差异最大,变异系数分别达到38.12%和37.59%;细胞结构指标中细胞面积差异最大,变异系数达到64.91%。(3)葡萄果肉质地评级分数与果实带皮和去皮测定的质构参数均达到显著或极显著相关关系,其中与带皮TPA硬度、胶着度和咀嚼性的相关系数最高,分别为0.578*、0.751**和0.789**;果肉质地评分与果肉细胞壁组成物质原果胶含量呈显著正相关关系(0.679*),与水溶性果胶/原果胶比值呈极显著负相关关系(-0.860**),而与其余的果肉细胞壁组成物质含量和4种关键酶活性均无显著相关性;果肉细胞结构参数、形状参数与果肉质地评分及质构参数的相关性均未达到显著水平,但酥脆果肉品种果肉细胞面积显著大于其他品种,软肉品种果肉细胞解体,细胞壁边界不清。研究表明,葡萄果肉硬度主要受果肉细胞降解影响,水溶性果胶/原果胶比值越高,果肉质地越软,水溶性果胶/原果胶比值以及带皮测定TPA硬度、胶着度和咀嚼性等指标可作为葡萄果肉质地的量化评价指标。  相似文献   

13.
1IntroductionIris identification is reputed to be one of the mostreliable biometric identification technologies.Wavelettheory has been widely used in feature analysis of the irisimage-the key to this technology.The classical irisrecognition algorithms were developed by Daugman[1]and Wildes[2].Zero-crossings of the wavelet transformwas presented by Boles[3].Gabor filter optimizationdesign for iris texture analysis and a multi-matchingsystem based on a simplified deformable model of thehuman i…  相似文献   

14.

[Purpose]

Efficacy and comparative characteristics of fine powdered whole soybean curd.

[Methods]

Ground dried soybean to a fine powder (700 mesh) containing bean components in its entirety, and then produced whole soybean curd. Analysed its nutritive components, bioactive substances, antioxidant activities and texture compared with pressed soybean curd.

[Results]

Compared with pressed soybean curd, the nutrients and isoflavone in whole soybean curd were slightly decreased, but antioxidant activities, dietary fibers and moisture content were increased. Also, the yield rate of the total process was improved 1.9 times.

[Conclusion]

Fine powdered whole bean curd has antioxidant effects, contains dietary fiber and possesses soft characteristics, hence has development potential in the diet market and as food for patients.  相似文献   

15.
In the late Middle and early Late Pleistocene, Neandertals inhabited a wide variety of ecological zones across western Eurasia during both glacial and interglacial times. To elucidate the still poorly understood effects of climatic change on Neandertal subsistence patterns, this study employs dental microwear texture analysis to reconstruct the diets of Neandertal individuals from various sites across their wide temporal and geographic ranges. The results of this study reveal environmentally-driven differences in the diets of Neandertal groups. Significant differences in microwear signatures, correlated with paleoecological conditions, were found among Neandertal groups that lived in open, mixed, and wooded environments. In comparison to recent hunter-gatherer populations with known, yet diverse diets, the occlusal molar microwear signatures of all the Neandertal groups indicate that their diet consisted predominantly of meat. However, the results of this study suggest that plant foods did form an important part of the diet of at least some Neandertal groups (i.e., those that lived in mixed and wooded habitats). Overall, the proportion of plant foods in the Neandertal diet appears to have increased with the increase in tree cover.  相似文献   

16.
Adult sea lamprey Petromyzon marinus attachment strength by the oral sucker was quantified. Surfaces with shallow, rounded discontinuities into which the oral fimbriae could be folded yielded the strongest seal and some fish could control their mouths to improve ‘suction’. Narrow grooves of 1 mm width and 3 mm depth prevented P. marinus from creating a lasting attachment.  相似文献   

17.
不同质地土壤的水热状况及其对冬小麦产量形成的影响   总被引:4,自引:0,他引:4  
对豫东平原3种质地土壤的水热状况和冬小麦籽粒生长特征进行了研究.结果表明,冬小麦籽粒生长阶段,粘壤土5cm处的日平均温度最低,为18.3℃,砂壤土最高,为19.5℃,中壤居中,为19.1℃.3种土壤的含水量大小顺序为粘壤>中壤>砂壤,粘壤土上小麦籽粒灌浆时间最长,千粒重最高,分别为38d和45.5g,砂壤土小麦籽粒灌浆时间最短,千粒重最低,分别为33d和42.4g,中壤土小麦2项指标居中,分别为36d和43.1g.高产栽培条件下,粘壤土冬小麦产量最高,为8253kg·hm-2,中壤次之,为7980kg·hm-2,砂壤最低,为7617kg·hm-2  相似文献   

18.
19.
N2O-loss rates from two soils were measured over a continuous observation period of 2 years. The two soils, differing in texture (sandy loam and silty loam), are frequently used for intensive crop production. Rates were estimated using a closed soil cover box technique. N2O-losses obtained were scrutinised with physical, chemical and microbiological properties of the soils as well as with climatic data.Large temporal changes in N2O-emission rates were found. The data were approximately log-normal distributed. In spring maximal values of 20 g N2O-N ha-1 d-1 were observed. According to this observation, two situations associated with high flux rates could be distinguished; 1. N2O- production by soil at spring thaw and 2. N2O-production within one week after N-fertilizer application. For both soils equal N2O-losses were found, which are adequate to 1 kg N2O-N ha-1 per year. From this data was calculated that N2O-losses ranged from 0.8–1.5% of the applied fertilizer N.  相似文献   

20.
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