共查询到20条相似文献,搜索用时 31 毫秒
1.
保护区的分类系统与标准 总被引:6,自引:1,他引:5
王献溥 《植物资源与环境学报》1992,(3)
保护区是一个泛称,根据建立的目的和本身的特点可以划分不同的类型,以利于管理工作的开展。每一个国家都应制订一个与本国资源和要求相适应的保护区分类系统。本文着重讨论按保护对象和保护区性质划分的保护区类型,以供判断每一个保护区的归属和管理重点。 相似文献
2.
《Anthrozo?s》2013,26(2):77-92
AbstractThis paper characterizes the portrayal of animals and human-animal relations in one genre of American popular culture—the “supermarket” tabloid press. A total of 789 animal-related stories and photographs in 82 issues of four tabloid magazines were analyzed according to theme. The items fell into nine categories in which animals were portrayed as objects of affection, saviors, threats, victims, things to be used, sex objects, imaginary and mythological beings, surrogate humans, and objects of wonder. It is argued that these themes represent archetypes reflecting the roles that animals have had in human cultural and psychological life since the historical origins of our species. 相似文献
3.
While it is generally agreed that culture and biology are both relevant to an understanding of human behavior, there is little consensus about the appropriate use of reductionist procedures. Disagreement abounds concerning the nature of the interaction and the relative contribution of distal and proximal mechanisms. An understanding of such issues may emerge only with long study of the interaction of variables at different conceptual levels of organization that intervene between the genes and culture. It is toward this larger end that the limited efforts of this paper are directed. Two cultural phenomena are considered: Murdoch's "social laws of sexual choice," and aspects of human ritual behavior. Although these constitute a unique organization of cultural items, I attempt to show how they are influenced by underlying biopsychological processes. I specifically reject, however, the view that cultural phenomena are isomorphic with, or can be completely reduced to, such processes. Emergent novelty and multiple possibilities are always present at more inclusive levels of organization. I argue that the relationship between the different sets of system variables is based on homologous functions and not merely on analogies.
SEYMOUR PARKER is Professor, Department of Anthropology, University of Utah, Salt Lake City. UT 84112 相似文献
SEYMOUR PARKER is Professor, Department of Anthropology, University of Utah, Salt Lake City. UT 84112 相似文献
4.
Gerhard Tutz 《Biometrical journal. Biometrische Zeitschrift》1989,31(3):259-272
A general class of sequential models for the analysis of ordered categorical variables is developed and discussed. The models apply if the ordinal response may be subdivided into two or more meaningful sets of response categories. The parametrization explicitly makes use of this subdivision. The models furnish a linear alternative to non-linear models which incorporate a scale parameter. They are shown to be special cases of multivariate generalized linear models. Applications are discussed with the use of several examples. 相似文献
5.
To cope with poor quality in cryo-electron tomography images, electron-dense markers, such as colloidal goldbeads, are often used to assist image registration and analysis algorithms. However, these markers can create artifacts that occlude a specimen due to their high contrast, which can also cause failure of some image processing algorithms. One way of reducing these artifacts is to replace high contrast objects with pixel densities that blend into the surroundings in the projection domain before volume reconstruction. In this paper, we propose digital inpainting via compressed sensing (CS) as a new method to achieve this goal. We show that cryo-ET projections are sparse in the discrete cosine transform (DCT) domain, and, by finding the sparsest DCT domain decompositions given uncorrupted pixels, we can fill in the missing pixel values that are occluded by high contrast objects without discontinuities. Our method reduces visual artifacts both in projections and in tomograms better than conventional algorithms, such as polynomial interpolation and random noise inpainting. 相似文献
6.
Biochemical and molecular species identification techniques have a broad range of applications in the management and conservation of marine organisms. While species boundaries are not always clearly defined, phylogeneticists utilise autapomorphic characters to distinguish phylogenetic species. Genetic markers discriminate between marine taxa when traditional morphological distinctions are unclear. The applications of these techniques can be divided into four general categories. Firstly, compliance enforcement, which often depends on genetic identification techniques to enable officials to identify the species to which regulations pertain. Secondly, quality control applications, to allow for the testing of marine products to guard against fraudulent substitution with less valuable species, which is particularly pertinent since processing often obliterates identifiable features. Thirdly, a variety of applications to ecological and life-history studies and conservation management are reported. Here, the genetic identification techniques of species from cryptic life-cycle stages or of morphologically indistinct species are an indispensable tool for marine scientists, conservators and managers. Lastly, the application of genetic techniques for sourcing population origin is briefly discussed. The biochemical and molecular techniques applied to species identification all exploit phenotypic or genotypic polymorphisms that are sampled using either tertiary level protein based methods or primary level DNA based methods. In this review, examples of the applications along with the total protein, allozyme, serological, PCR and other DNA based methodologies are briefly described and some generalities with regard to their use are presented. 相似文献
7.
This paper aims at detecting the relationships between phytogeographical patterns of genera of Chinese endemic seed plants and latitude or climatic factors. The landmass of China was divided into four latitudinal zones, each of c. 8°. Based on a total of 1664 indigenous genera of Chinese endemic seed plants which were grouped into fifteen geographical elements, belonging to three major categories (cosmopolitan, tropical and temperate) and which were absent or present in 28 provinces in China, we analyzed the phytogeographical patterns of genera of Chinese endemic seed plants and detected the relationships between them and main climatic factors. Our results showed that the proportion of tropical genera decreases with the increase in latitude; the proportion of temperate genera increases with the increase in latitude; and the proportion of cosmopolitan genera increased gradually increased gradually with latitude. There are a slow decrease in the proportion of tropical genera and slow increase in the proportion of temperate genera at latitudes 35°–40°. Alternatively, the tropical genera and the temperate genera have the same proportion at latitude c. 25°. These changes and issues about the different genera also appeared in main climate factors. In general, the genera present in a more northerly flora are a subset of the genera present in a more southerly flora. In summary, the large-scale patterns of phytogeography of endemic flora in China are strongly related to latitude, which covary with several climatic variables such as temperature. 相似文献
8.
Bias in random forest variable importance measures: Illustrations,sources and a solution 总被引:6,自引:0,他引:6
Background
Variable importance measures for random forests have been receiving increased attention as a means of variable selection in many classification tasks in bioinformatics and related scientific fields, for instance to select a subset of genetic markers relevant for the prediction of a certain disease. We show that random forest variable importance measures are a sensible means for variable selection in many applications, but are not reliable in situations where potential predictor variables vary in their scale of measurement or their number of categories. This is particularly important in genomics and computational biology, where predictors often include variables of different types, for example when predictors include both sequence data and continuous variables such as folding energy, or when amino acid sequence data show different numbers of categories. 相似文献9.
D Kersten 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》1997,352(1358):1155
The central problems of vision are often divided into object identification and localization. Object identification, at least at fine levels of discrimination, may require the application of top-down knowledge to resolve ambiguous image information. Utilizing top-down knowledge, however, may require the initial rapid access of abstract object categories based on low-level image cues. Does object localization require a different set of operating principles than object identification or is category determination also part of the perception of depth and spatial layout? Three-dimensional graphics movies of objects and their cast shadows are used to argue that identifying perceptual categories is important for determining the relative depths of objects. Processes that can identify the causal class (e.g. the kind of material) that generates the image data can provide information to determine the spatial relationships between surfaces. Changes in the blurriness of an edge may be characteristically associated with shadows caused by relative motion between two surfaces. The early identification of abstract events such as moving object/shadow pairs may also be important for depth from shadows. Knowledge of how correlated motion in the image relates to an object and its shadow may provide a reliable cue to access such event categories. 相似文献
10.
R. H. Allen 《CMAJ》1965,93(14):760-761
Many new types of laboratory equipment are appearing on the market, as well as a large number of reagent sets or kits. The importance of adequate evaluation of the reliability of such new products cannot be overemphasized.Commercially prepared reagent sets or kits fall into two categories. In the one, a set of reagents is offered for use in performance of a particular conventional procedure; this type of prepared reagent should present no problem, provided that the reagents are stable. In the other category, a reagent kit or set is offered which has been designed to simplify the performance of a laboratory analysis, often by combining reagents and reducing the number of steps and the time required. Such a kit should be evaluated carefully in order to determine its efficiency and limitations. In general it is difficult to simplify greatly a laboratory procedure without sacrificing its accuracy. 相似文献
11.
Azole antifungals are used to treat a myriad of fungal infections in diverse patient populations. As a result, it becomes clear that use of one size fits all azole dosing regimens is illogical. Three general variable categories are essential to consider when developing an approach the management of fungal infections with the azoles. These categories are the pharmacological, microbiological, and host. In the clinical setting information regarding microbiological variables if often lacking; however, host and pharmacological data are abundant. Unfortunately, these available data are not always used to construct individualized dosing strategies. In this review, host and pharmacological factors that can influence azole activity will be presented. Additionally, recommendations will be provided to help the clinician optimize azole dosing regimens based on these variables. 相似文献
12.
Background
The most popular methods for significance analysis on microarray data are well suited to find genes differentially expressed across predefined categories. However, identification of features that correlate with continuous dependent variables is more difficult using these methods, and long lists of significant genes returned are not easily probed for co-regulations and dependencies. Dimension reduction methods are much used in the microarray literature for classification or for obtaining low-dimensional representations of data sets. These methods have an additional interpretation strength that is often not fully exploited when expression data are analysed. In addition, significance analysis may be performed directly on the model parameters to find genes that are important for any number of categorical or continuous responses. We introduce a general scheme for analysis of expression data that combines significance testing with the interpretative advantages of the dimension reduction methods. This approach is applicable both for explorative analysis and for classification and regression problems. 相似文献13.
The utility of a relatively new multivariate method, bi-linear modelling by cross-validated partial least squares regression (PLSR), was investigated in the analysis of QTL. The distinguishing feature of PLSR is to reveal reliable covariance structures in data of different types with regard to the same set objects. Two matrices X (here: genetic markers) and Y (here: phenotypes) are interactively decomposed into latent variables (PLS components, or PCs) in a way which facilitates statistically reliable and graphically interpretable model building. Natural collinearities between input variables are utilized actively to stabilise the modelling, instead of being treated as a statistical problem. The importance of cross-validation/jack-knifing as an intuitively appealing way to avoid overfitting, is emphasized. Two datasets from chromosomal mapping studies of different complexity were chosen for illustration (QTL for tomato yield and for oat heading date). Results from PLSR analysis were compared to published results and to results using the package PLABQTL in these data sets. In all cases PLSR gave at least similar explained validation variances as the reported studies. An attractive feature is that PLSR allows the analysis of several traits/replicates in one analysis, and the direct visual identification of individuals with desirable marker genotypes. It is suggested that PLSR may be useful in structural and functional genomics and in marker assisted selection, particularly in cases with limited number of objects. 相似文献
14.
van Hintum TJ 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,115(3):343-349
The results of genetic diversity studies using molecular markers not only depend on the biology of the studied objects but
also on the quality of the marker data. Poor data quality may hamper the correct answering of biological questions. A new
statistic is proposed to estimate the quality of a marker data set with regard to its ability to describe the structure of
the biological material under study. This statistic is called data resolution (DR). It is calculated by splitting a marker
data set at random into two sets each with half the number of markers. In each set, similarities between all pairs of objects
are calculated. Subsequently, the similarities obtained for the two sets are correlated. This process is repeated a large
number of times. The average of the correlation coefficients obtained in this way is the DR of the dataset. In the present
paper, the DR statistic is applied to four studies involving amplified fragment length polymorphism as well as micro-satellite
markers. In addition, some properties and possible applications of DR are discussed, including the prediction of the added
value of scoring additional markers, and the determination of which similarity measure is, apart from genetical considerations,
most appropriate for analyzing the data. 相似文献
15.
Porzelius C Johannes M Binder H Beissbarth T 《Biometrical journal. Biometrische Zeitschrift》2011,53(2):190-201
Classification of patients based on molecular markers, for example into different risk groups, is a modern field in medical research. The aim of this classification is often a better diagnosis or individualized therapy. The search for molecular markers often utilizes extremely high-dimensional data sets (e.g. gene-expression microarrays). However, in situations where the number of measured markers (genes) is intrinsically higher than the number of available patients, standard methods from statistical learning fail to deal correctly with this so-called "curse of dimensionality". Also feature or dimension reduction techniques based on statistical models promise only limited success. Several recent methods explore ideas of how to quantify and incorporate biological prior knowledge of molecular interactions and known cellular processes into the feature selection process. This article aims to give an overview of such current methods as well as the databases, where this external knowledge can be obtained from. For illustration, two recent methods are compared in detail, a feature selection approach for support vector machines as well as a boosting approach for regression models. As a practical example, data on patients with acute lymphoblastic leukemia are considered, where the binary endpoint "relapse within first year" should be predicted. 相似文献
16.
C R Guglielmino G Zei L L Cavalli-Sforza 《Human biology; an international record of research》1991,63(5):607-627
The study of names as cultural characters and of surnames, which behave like genetic markers, is useful for comparing cultural and genetic transmission. Genetic transmission has a unique vertical component, which also can be present in the transmission of cultural traits associated with a horizontal (or epidemic) component resulting from local customs or fashion. Our aims in this study are to infer genetic patterns in Sicily from surnames and names and to evaluate and compare the consequences of vertical versus horizontal transmission of cultural markers. Names and surnames of 88,383 consanguineous spouses collected in 16 dioceses of Sicily were analyzed by multivariate analysis to reveal and compare the geographic clusters obtained from both sets of data. As a result, both data sets indicate a major separation between the eastern and the western region of Sicily. Also, distance matrices obtained from names are highly correlated with those from surnames. But names seem to form fewer and larger geographic clusters, whereas surnames are more greatly subdivided into smaller clusters. The most common male names present a different pattern from surnames. Vertical transmission is the cause of the similarity of the main geographic patterns of names and surnames and their correspondence with findings from geography of genes, and horizontal cultural transmission explains the major differences. Furthermore, the genetic and cultural affinities can be correlated with the historical background of Sicily. 相似文献
17.
Microfilaments and actin-associated proteins at sites of membrane-substrate attachment within acetylcholine receptor clusters 总被引:4,自引:0,他引:4
Robert J. Bloch Marisela Velez Jacqueline G. Krikorian Daniel Axelrod 《Experimental cell research》1989,182(2):583-596
Rat myotubes in tissue culture form broad areas of close contact with the substrate. These areas often display two distinct, interdigitating sets of membrane domains. One, the "contact domain", is close to the substrate; the other, termed the "AChR domain", is further from the substrate and is rich in acetylcholine receptors (AChR). We have used fluorescence techniques to study the organization of the cytoskeleton in these areas. Substrate-apposed membrane of the myotubes was exposed either by shearing or by permeabilizing the cells with a neutral detergent. Phalloidin derivatives and affinity-purified polyclonal or monoclonal antibodies specific for cytoskeletal proteins were then applied to the samples. Sheared samples were observed by epifluorescence microscopy; detergent-permeabilized samples were observed by total internal reflection fluorescence microscopy. We found that, like antivinculin, fluorescent phalloidin derivatives and antibodies to alpha-actinin, filamin, and talin preferentially labeled the contact domains. This suggests that bundles of microfilaments associate with the membrane at sites of myotube-substrate attachment. In contrast, a 43K protein, closely associated with AChR, was present only at AChR domains. A monoclonal antibody to actin labeled both AChR and contact domains, suggesting that actin is enriched over both regions. Our results suggest that, like the plasma membrane of AChR clusters, the underlying membrane skeleton is organized into at least two distinct domains. 相似文献
18.
This article examines the development of the ‘cultural competition’ as a site for the production of multiple identities by Indian American youths on American college campuses. Through the examination of two categories of folk dance competitions (bhangra and raas-garba) at a private university in Washington, DC, we argue that these competitions appear to resist hybridity and produce rhetoric that marginalizes diasporic culture in favour of the ‘pure’ and ‘authentic’ culture of the homeland. However, the goal of expressing uncontaminated ‘authentic’ culture is not realized as diasporic identities and cultures consistently interrupt and undermine homogenizing narratives of ‘tradition’ and ‘authenticity’. We also demonstrate that these folk dance groups often reinforce an ethno-regional distinctiveness rather than a hybrid or pan-Indian identity. 相似文献
19.
Pacquiao D 《Bioethics forum》2001,17(1):27-31
Shared meanings and socially constructed realities have great significance to individuals and families facing critical illness, pain, suffering, or death. Actions are often based on the context of the professional and dominant societal culture. The concept of Advance Directives is consistent with the dominant value orientation in the American culture of self-reliance and individualism, which places a high premium on self-determination and control of one's own destiny. However, this value is not always consistent with the dominant cultural views of particular sick or dying individuals. Thus, at a time when individuals and their families need the most support, institutionalized care often creates incongruities and meaninglessness. 相似文献
20.
Richmond SR Godard MP 《Journal of strength and conditioning research / National Strength & Conditioning Association》2004,18(4):846-849
The purpose of this study was to determine the rate of recovery for recreational weight trainers between 2 sets of bench press to volitional exhaustion. Twenty-eight men performed 2 sets of the bench press at 75% of their previously determined 1 repetition maximum (1RM) to volitional exhaustion. Rest periods of 1, 3, or 5 minutes between sets were utilized on the 3 separate testing days. There was a significant decrease in the number of repetitions performed between the second sets at all rest periods. There were no significant differences in work performed (repetitions x weight) during the second set with the 3- and 5-minute rest periods, but the total work with a 1-minute rest period (1,389.1 +/- 529.9) was significantly less than both the 3- (1,494.9 +/- 451.0) and 5-minute (1,711.4 +/- 478.0) rest period. The data indicated that subjects were unable to fully recover between the first and second sets of maximal resistance exercise, regardless of the rest period. However, subjects were able to maintain a performance level of 8-12 repetitions and sustain the total work performed per set with as little as 3 minutes rest between sets. 相似文献