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1.
In designing a yard layout for a container terminal several decisions have to be made. In this paper we propose a model which provides decision support for the design of yard layouts of terminals at which straddle carrier are used. We assume that straddle carriers are used for the horizontal transport and the stacking of containers. For the proposed model we develop estimates for the expected cycle distances of straddle carriers. In this case, we distinguish between cycles to landside facilities and to the quay. Numerical results are presented for several parameter settings. For instance, we present results for a comparison of layouts where the rows in the block are orientated parallel with layouts where the rows are orientated perpendicularly to the quay.  相似文献   

2.
In a series of previous studies, it has been shown that populations of the common morning glory Ipomoea purpurea are typically polymorphic for flower-color genes that bias pollinator service and, hence, the rate of outcrossing. In this study, we show that the rate of outcrossing for the white flower-color morph depends on its frequency in experimental populations of the morning glory. White flowers are visited less often by the primary pollinator, bumblebees, and have lower outcrossing rates than colored flowers when they are in the minority. In contrast, blue or pink flower morphs are not undervisited and do not have lowered outcrossing rates when they are rare. In plant populations where genes that increase selling are selectively favored due to their transmission bias, undervisitation of rare morphs may act to stabilize genetic variation for outcrossing rates.  相似文献   

3.
4.
Holm's (1979) step-down multiple-testing procedure (MTP) is appealing for its flexibility, transparency, and general validity, but the derivation of corresponding simultaneous confidence regions has remained an unsolved problem. This article provides such confidence regions. In fact, simultanenous confidence regions are provided for any MTP in the class of short-cut consonant closed-testing procedures based on marginal p -values and weighted Bonferroni tests for intersection hypotheses considered by Hommel, Bretz and Maurer (2007). In addition to Holm's MTP, this class includes the fixed-sequence MTP, recently proposed gatekeeping MTPs, and the fallback MTP. The simultaneous confidence regions are generally valid if underlying marginal p -values and corresponding marginal confidence regions (assumed to be available) are valid. The marginal confidence regions and estimated quantities are not assumed to be of any particular kinds/dimensions. Compared to the rejections made by the MTP for the family of null hypotheses H under consideration, the proposed confidence regions provide extra free information. In particular, with Holm's MTP, such extra information is provided: for all nonrejected H s, in case not all H s are rejected; or for certain (possibly all) H s, in case all H s are rejected. In case not all H s are rejected, no extra information is provided for rejected H s. This drawback seems however difficult to overcome. Illustrations concerning clinical studies are given.  相似文献   

5.
In the majority of natural situations in which bacteria are found, they are associated with and attached to surfaces. In the presence of moisture and nutrients, they grow to form extensive bacterial films which are often enveloped within copius exopolymeric matrices. Biofilms are ubiquitous to many different situations in industry, the environment and medicine. Their presence can be either beneficial or more commonly detrimental to such systems. In this respect, biofilm populations possess physiological properties distinct from those of unattached, planktonic bacteria. Moreover, it is generally accepted that bacteria growing within a biofilm are more resistant to antimicrobial agents than their planktonic counterparts. However, although the consequences of attachment to antimicrobial resistance have been known for many years, the mechanistic bases for such effects have still to be fully elucidated. In this article the nature of different resistance mechanisms, including those of the exopolymeric matrix, environmental modulation, attachment-specific physiologies and quorum sensing are reviewed.  相似文献   

6.
杨磊  张春明  王德芝 《生物磁学》2009,(13):2590-2593
体外展示技术包括核糖体展示技术、mRNA展示技术、DNA展示技术,是在无细胞蛋白质表达体系内将基因型和表型通过一定的方法连接在一起,体外高通量的筛选多肽和蛋白质的技术。抗体的产生是一个不断选择的过程,利用体外展示技术在体外选择针对某一抗原的抗体分子,并结合基因工程技术对抗体进行改造,以产生高亲和力、高特异性的抗体。体外展示技术的研究和应用已越来越广泛,有望成为下一代的抗体制备技术。  相似文献   

7.
本文报道中国假尾孢属的24个种,其中有2个新种:杨桐假尾孢(Pseudocercospora adinandrae Guo&Liu),钟萼假尾孢(Pseudocercospora bretschneiderae Liu&Guo),10个新组合,1个新名称:木豆假尾孢(Pseudoeercospora cajani-flavi Guo&Liu)和11个中国新记录。文中对2个新种提供了拉丁文简介、描述及图。所研究的标本全部保存在中国科学院微生物研究所真菌标本室(HMAS)。  相似文献   

8.
In many regions in the Netherlands the care for stroke patients is organised in a coordinated stroke service. Within these stroke services, each year more patients are referred to nursing homes for a period of rehabilitation. A stroke leads to lasting cognitive and emotional consequences in more than half of the stroke patients. These consequences interfere with the daily life of the patients and their caregivers. Due to the nature and severity of these problems specific care is needed in the nursing home. In the present article a procedure for cognitive screening in a nursing home is described and data of a large group of patients are presented. These data clearly show the magnitude of the cognitive problems: high percentages of impairments are found in many cognitive domains. In the discussion therefore arguments are given for specialised care - assessment as well as treatment - in the nursing home for stroke patients with cognitive deficits.  相似文献   

9.
Weakly electric fish produce electric signals with a specialised organ in their tail. In addition, they are electrosensitive and can perceive their self-generated signals (for electrolocation) and electric signals of other electric fishes (for electrocommunication). Mormyrids possess three types of peripheral electroreceptor organs, one used for electrocommunication and two types involved in electolocation. They are innervated by afferent fibres, which project to different zones in the electrosensory lateral line lobe (ELL) in the medulla. Brain circuits for electrolocation and electrocommunication are separated almost throughout the whole brain. Electrolocation pathways run from the ELL-cortex to the torus semicircularis of the midbrain and then via the valvula cerebelli towards the telencephalon. Pathways involved in electrocommunication run from the nucleus of the ELL to another part of the torus and from there through the isthmic granule nucleus to the valvula. In addition, a pathway via the preglomerular complex to the telencephalon might exist. In both the electrolocation and the electrocommunication circuits, prominent recurrent pathways are present.  相似文献   

10.
11.
Microarrays: technologies overview and data analysis   总被引:2,自引:0,他引:2  
DNA microarrays are a powerful tool to investigate differential gene expression for thousands of genes simultaneously. In this review, recent advances in DNA microarray technologies and their applications are examined. Various DNA microarray platforms are described along with their methods for fabrication and their use. In addition some algorithms and tools for the analysis of microarray expression data, including clustering methods, partitioning and machine learning methods are discussed.  相似文献   

12.
Common marmosets are suitable non-human primate models for many human diseases. Standard values for blood parameters are required to evaluate physiological and pathological situations. Two studies were conducted: study I to determine standard values and study II to examine these under changed housing conditions. In study I, all parameters for clinical chemistry were similar in range for both genders with these specifics: male marmosets had significantly higher total and LDL cholesterol levels than females, whereas the mean corpuscular volume and the mean corpuscular haemoglobin were significantly lower than in females. In study II, glucose, lymphocytes and salivary cortisol were significantly lower, and faecal cortisol was increased during the change of housing conditions. In conclusion, standard values for haematology and clinical chemistry for the common marmoset were determined. Further on, parameters that are influenced by relocation stress and its importance for experimental results are described.  相似文献   

13.
An attempt has been made to use some structures of the external genitalia in the taxonomy of termites. Twenty-five species of four largest families were examined. Only the female external genitalia appeared to be suitable for identification of species, with some genital structures (medisternite, basivalvae, parasternites, etc.) being most important for these purposes. The taxonomic suitability of these structures is different in different families. In the family Kalotermitidae, the medisternite and spermathecal opening are strongly sclerotized and suitable for the species identification, whereas the basivalvae are reduced or lost. In Hodotermitidae, the basivalvae are well-developed and their shape is different in different species. Structural features of the basivalvae and spermathecal opening are species-specific in Rhinotermitidae, the shape of the basivalvae and position of the spermathecal opening, in Termitidae. In addition, species of Termitidae have a characteristic strigation of the basivalvae. In Macrotermitinae and Nasutitermitinae, the anterior margins of sternite IX are well sclerotized and form parasternites. The structures proposed by us as diagnostic vary only within species.  相似文献   

14.
We present data on the frequencies of nucleotides and nucleotide substitutions in conservative DNA regions involved in the regulation of gene expression. Data on prokaryotes and eukaryotes are considered separately. In both cases DNA strands complementary to those which serve as templates for RNA-polymerase have low frequencies of cytosine. The most conservative positions also have an increased frequency of adenine. Various substitutions in the series of homologous regulatory DNA sequences, as compared to their consensuses, have different frequencies. In prokaryotes guanine in a consensus sequence is substituted for at the lowest and adenine at the highest frequency, whereas in eukaryotes cytosine is substituted for at the lowest and guanine at the highest frequency. In both cases the nucleotides substituted for are most frequently replaced with cytosine. Deviations from consensus sequences tend to cluster in adjacent positions. The more pronounced the consequences of a nucleotide substitution are the higher is the frequency of substitutions in adjacent positions. Possible explanations for these phenomena are discussed.  相似文献   

15.
In a recent review article by Mani published in 1990, it was shown that the changes in the frequency of the morph carbonaria can be explained through a migration-selection model and the model is capable of reproducing the decrease in the carbonaria frequency since the enactment of Clean Air Acts. In this paper new data both for carbonaria and for insularia up to 1990 for West Kirby in NW England and for Cambridge are presented. In the earlier review, the data for West Kirby extended to 1987 and for Cambridge to 1985. Data not previously published for the carbonaria and the insularia frequencies at sites in Northwood in Middlesex, Egham in Surrey and Ringwood in Hampshire are also presented. A migration-selection model was used to predict the change in the frequencies of the melanic morphs up to the year 2010. All the data are compared with the predictions of the model. It is encouraging that the data follow the theoretical predictions.  相似文献   

16.
17.
Overview of mycotoxin methods, present status and future needs   总被引:2,自引:0,他引:2  
Gilbert J 《Natural toxins》1999,7(6):347-352
This article reviews current requirements for the analysis for mycotoxins in foods and identifies legislative as well as other factors that are driving development and validation of new methods. New regulatory limits for mycotoxins and analytical quality assurance requirements for laboratories to only use validated methods are seen as major factors driving developments. Three major classes of methods are identified which serve different purposes and can be categorized as screening, official and research. In each case the present status and future needs are assessed. In addition to an overview of trends in analytical methods, some other areas of analytical quality assurance such as participation in proficiency testing and reference materials are identified.  相似文献   

18.
R J Tallarida 《Life sciences》1988,43(26):2169-2176
Determinations of apparent equilibrium dissociation constants of drug-receptor interactions are made from both functional and radioligand binding studies. In each type of study, reversible reactions are assumed and the mass action law is applied. Functional studies are frequently used to determine the dissociation constant of a competitive antagonist but are less frequently used to obtain this constant for agonist compounds since the latter determination requires an experimental procedure that irreversibly inactivates a fraction of the receptors. In the present report, values of dissociation constant for prototype agonists and antagonists, determined from binding and from functional studies, are examined in two classical isolated preparations, rabbit aorta and guinea-pig ileum. In each preparation the dissociation constants from binding and functional experiments agree well for the antagonists but differ markedly for the agonists. Further, the dissociation constant values from binding are seen to be greater for the agonists than for the antagonists. When a chronic treatment regimen in the rabbit resulted in a pronounced change in the functional dissociation constant of subsequently administered norepinephrine, there was no significant change in either the binding constant of this agonist or in the pA2 value of the alpha antagonist, phentolamine. These, and the previously described results, are shown to be compatible with a simple two-state receptor model in which agonists bind with high and low affinity to each state while antagonists do not distinguish between the states. In this model, the ratio of low to high affinity states accounts for the failure of the binding procedure to detect changes in the agonists dissociation constant that are highly significant in the functional study. Whereas the model is based on data for these two classical preparations only, and may not be more generally applicable, the findings demonstrate the necessity for employing both functional and radioligand binding experiments when characterizing drug receptors.  相似文献   

19.
In this paper two staining methods for automatic assessment of nucleolar profile area in paraffin sections of breast carcinomas using the IBAS 2000 image analyzer are reported. In the first method, the nucleolar proteins are stained with phloxine B, in the second the nucleolar RNA is stained with methyl green-pyronin. Both methods are fully reproducible. Statistically, the profile areas observed for the same patient by the two methods were found not to differ significantly. Because of their rigidity and their size in relation to section thickness, nucleoli are particularly attractive cell structures for quantitation, for instance in studies of variables that might be useful in establishing the prognosis for carcinoma patients.  相似文献   

20.
In this paper two staining methods for automatic assessment of nucleolar profile area in paraffin sections of breast carcinomas using the IBAS 2000 image analyzer are reported. In the first method, the nucleolar proteins are stained with phloxine B, in the second the nucleolar RNA is stained with methyl green-pyronin. Both methods are fully reproducible. Statistically, the profile areas observed for the same patient by the two methods were found not to differ significantly. Because of their rigidity and their size in relation to section thickness, nucleoli are particularly attractive cell structures for quantitation, for instance in studies of variables that might be useful in establishing the prognosis for carcinoma patients.  相似文献   

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