中国上石炭统滑石板阶层型剖面的蜓

本文详细研究了贵州盘县滑石板村滑石板阶层型剖面的蜓?C0喽锶海?属26种及亚种,其中1未定种。滑石板阶包含2个蜓?B4籔seudostaffella antiqua-P．antiqua posterior带及Pseudostaffella composita-P．paracompressa带。滑石板阶底界以蜓?BB疎ostaffellina protvae—Pseudostaffella antiqua演化系列中Pseudostaffella antiqua首次出现为标志,具体位置在层型剖面的层1,层型点置于层1之底AAK56点上;顶界止于筵化石Profuslinella priscoidea带之底。滑石板阶的Pseudostaffella antiqua-P．antiqua posterior带可以和俄罗斯下巴什基尔阶Severoketmensky层的Pseudostaffella antiqua带对比;滑石板阶的Pseudostaffella composita—P．paracompressa带大致与俄罗斯下巴什基尔阶Prikamsky层的Pseudostaffella praegorski—Profusulinella staffellaeformis带的一部分对比。滑石板阶大致相当于国际地层表中的巴什基尔阶(Bashkirian)中部。     

越南下龙湾石炭纪巴什基尔期Pseudostaffella(筵)类动物群

作者报道了越南下龙湾地区的一个(筵)类动物群,该动物群产于下龙湾吉婆岛东的一个小岛的石灰岩地层中,其中以Pseudostaffella为主,Eostaffella次之.文中描述7个种,即:Pseudostaffella composita,P.subquadrata vozhgalica,P.antiqua,P.antiqua grandis,Eostaffella postmosquensis,E.mosquensis及E.galinae,其中以Pseudostaffella composita最为丰富,可称之为Pseudostaffella动物群.该动物群层位高于下龙湾地区Bacson组中的Millerella-Eostaffella带,相当于宾夕法尼亚系巴什基尔阶上部,中国贵州盘县滑石板阶层型剖面的Pseudostaffella composita-P.paracompressa带,俄罗斯下巴什基尔阶Prikamsky层的Pseudostaffella prae-gorskyi-Profusulinella staffellaeformis带的一部分,以及北美宾夕法尼亚系莫洛阶Millerella带与阿托克阶Profusulinella组合带之间的Pseudostaffella和Eostaffella的化石层.下龙湾Pseudostaffella(筵)类动物群的发现具有重要的地层学和古生物学意义,它对于进一步认识该地区地质演化及古生物地理变迁均有裨益.     

Cell Growth and the Structure and Mechanical Properties of the Wall in Internodal Cells of Nitella opaca: II. MECHANICAL PROPERTIES OF THE WALLS

The internodal cells of Nitella opaca L. have been used in anattempt to assess the part which mechanical properties of thewall may play in the control of cell growth. It is shown thatthe wall is mechanically anisotropic in both its plastic andelastic properties, and evidence is presented which indicatesthat this arises from its anisotropy of structure. The degreeof anisotropy is greater in cells with a high growth-rate thanin those with a low growth-rate. Evidence is presented thatthis variation in properties with growth-rate is due wholly,or in part, to changes in the orientation of the crystallinecomponent, in the relative proportion of wall constituents,and in the condition of active groups of the wall components.The findings are in harmony with the theory that extension growthof the cell wall is due to ‘creep’, i.e. disturbancesof the molecular forces within the wall leading to a slow plasticyielding to turgor pressure.     

The epigenetic mechanism of the effect of mildly deleterious mutations on the viability of the progeny and their correction in meiosis

Data supporting the hypothesis about the epigenetic nature of deleterious mutations leading to the death of a part of the progeny are presented. It is assumed that during the life cycle “mutant” variants of formation of structural-functional loop domains occur in chromosomes that normally are corrected during meiosis. An abnormal loop changes the activity of many tens of genes, both increasing (+) and decresing (−) it, which affects the viability of homozygotes and to a lesser extent the viability of heterozygotes. Hybrids with chromosomes containing independently accumulated deleterious mutations partly restore their viability due to the complementary interactions of + and − genes.     

Origin of the Coleorhiza in Cycad Seedlings and its Structural Homology with That of the Poaceae

In the literature there is disagreement about the existence of a coleorhiza in cycad embryos. In this paper the terminology of the cycad ovule, seed and embryo is revised. It was confirmed that the cycad ovule and seed are pachychalazal and that the seed coat is exclusively formed by the pachychalaza. The term ‘pleurotesta’ as a substitute for the so-called ‘endotesta’ is suggested to describe the inner, membranous part of the seed coat. The anatomy of the cycad embryo was studied in comparison with the grass embryo and it was found that a coleorhiza does exist in cycad embryos and derives from the distal part of the suspensor. It is postulated that the coleorhiza in grasses also derives from the distal part of the suspensor and that the two structures are therefore structurally homologous.     

Structure of the bank vole (<Emphasis Type="Italic">Myodes glareolus</Emphasis>) population cycles in the core and periphery of its species area

The results of long-term studies of two bank vole (Myodes glareolus) populations in stationary sites in the central part and periphery of its species area are described. Four phases of a multiannual population cycle and two of its structural parts have been detected for both populations. The first part of the cycle is “determined,” with the “peak” phase passing into a “depression” (population collapse). This transition is mainly determined by intrapopulation processes and is weakly dependent on the external conditions of each individual year. The second part is “stochastic,” starting from a stable point in the cycle in the depression phase. The duration of the second part is determined by the state of the population and its ability to increase its size, as well as by the weather and food factors, predation pressure, and location of the population within the species area. The transition from the peak phase to the depression phase (the determined part) for both populations takes place during one fall-winter-spring season and has no effect on the cycle duration. The duration of the stochastic part in the core of the species area (the period from depression phase to peak phase) is 1–3 years and in the periphery, 2–4 years.     

Stimulation of trophoblastic giant cell differentiation in the homozygousYellow mouse embryo

Escape from pre-implantation lethality by homozygousyellow embryos depends on differentiation of trophoblastic cells. The evidence presented herein suggests that progesterone stimulated differentiation of trophoblastic giant cells in some homozygousyellow blastocysts and thereby increased the percentage ofA ^y/A^y “escaper” embryos. This work was supported in part by funds from research grant HDOOO36, National Institute of Child Health and Development, National Institutes of Health, U.S.A.     

Is there a Real Nexus Between Ethics and Aesthetics?

Aesthetics is a vexed topic in philosophy, with a long history. For my purposes, an aesthetic experience is a foundational affective response to an object, to which terms such as “ugly”, “beautiful”, “pretty” or “harmonious” are applied. These terms are derived from a Discourse of aesthetics; some remain constant, others change from generation to generation. Aesthetics and ethics have been linked in Western thought since the days of Plato and Aristotle. This essay examines what is happening to that link in contemporary experience. It emphasises the ways in which the popular media exploit aesthetic appeal to penetrate their market, and to exploit and frame intuitive responses to current and past events. Production values, the artfulness of editors and the financial interests of producers and directors thus do much to determine contemporary aesthetic and ethical judgements. That which is beautifully presented invites the ethical involvement of the audience. Events whose images are beautifully presented constitute “hyperevidence”, a pre-judged, reinforced and amplified illusion of reality and participation. Understanding how aesthetic excellence draws audiences into ethical relationship with what is presented becomes an important part of education in ethics, including bioethics.     

Structure of the school of sock-eyed salmon <Emphasis Type="Italic">Oncorhynchus nerka</Emphasis> from the Apuka River (the Northeastern Kamchatka)

Results of study of sock-eyed salmon Oncorhynchus nerka from the Apuka River—the largest river of the northeast of Kamchatka—inflowing Olyutorskii Bay of the Bering Sea are presented. It is established that the school of the Apuka River is represented by the early-run sock-eyed salmon that spawns in Lake Vatyg-Gytkhyn located in the lower part of the basin and by individuals of the later run that spawn in the upper reaches of the river. Early-run sock-eyed salmon appears in the river with signs of spawning changes and a high value of gonadosomatic index (GSI). Late-run sock-eyed salmon migrates to the river without signs of spawning changes and with a relatively low GSI. The age composition of spawners of the early- and late-run sock-eyed salmon is different.     

Diet of the Oligocene anthropoidsAegyptopithecus andApidium

Diets of the Oligocene anthropoidsAegyptopithecus zeuxis andApidium phiomense are inferred from measurements of the anterior and posterior dentition of these species. Ideas are presented which can be checked as the hypodigms expand. Comparisons with extant anthropoids demonstrate a probably frugivorous diet forA. zeuxis, while the diet ofA. phiomense was not characterized by a high degree of frugivory requiring extensive incisal preparation of food. Additional inferences about the diet ofA. phiomense might be gleaned from future examination of incisor morphology, implantation and occlusion. Even when allowance is made for the presence of P2 inA. phiomense, the dietary position of this species with respect to extant anthropoids is equivocal, and it is possible that the normal anthropoid relationship between anterior and posterior dentitions, with a small incisor span correlating with a great amount of mastication, had yet to be developed. This report is based in part on an invited paper “Function in primate masticatory musculature as demonstrated by muscle weights” delivered at the symposium “The Behavioral and Morphological Adaptations to Diet Among Primates,” 46th Annual Meeting, American Association of Physical Anthropologists, Seattle, Washington, April 13–16, 1977.     

Ramp edges,Mach bands,and the functional significance of the simple cell assembly

The responses of “complex” simple cells to sharp and blurred ramp edges were studied. These responses are quite similar to those in the case of lines, which implies that phase information cannot be used to discriminate between ramp edges and lines. Furthermore, if the maximum of the modulus is used as a position estimate, a systematic bias toward the ramp side results, and this bias increases with edge blur. In contrast, a local extremum in the real part of the cell responses provides a precise position estimate, even for strongly blurred edges. Possible multiscale detection strategies are discussed in the context of a syntactical visual reconstruction. This is illustrated by an explanation of Mach bands as perceived at trapezoidal edges, including Ratliff’s Mach-band cancellation stimulus, and criteria for local probability summation in the prediction of Mach-band detection thresholds are presented. Received: 10 December 1992/Accepted in revised form: 6 August 1993     

Sexual discrimination in the hermit crabPagurus geminus

Factors concerning sexual discrimination and related sensory receptors were investigated on the hermit crabPagurus geminus. In the breeding season, male crabs of this species were observed to hold receptive females but to reject males. By using this behavior, it was examined whether males on which some operation on the sensory receptors was performed could discriminate between presented male of female crabs. Test males could not discriminate sexes of the presented crabs only when antennules were removed bilaterally. On the other hand, intact test males reacted positively to an empty shell from which “female water” exuded after passing through the chamber containing females. Thus, the factor by which the hermit crab discriminates sexes was indicated to be a water-borne chemical and that the sensory receptor related to sex-discrimination appeared to exist on the antennules. Discussions are made with respect to predicted substances taking part in sexual discrimination of this hermit crab.     

A multidimensional birth process and its application to some problems in the dynamics of biological populations

This paper is a sequel to a paper by the author entitled “Restricted Transition Probabilities and Their Applications to Some Problems in the Dynamics of Biological Populations” (Bull. Math. Biophysics, 1966,28, 315–331). The paper is divided into two parts. In part one some aspects of the maximum size attained by the population during a finite time interval are studied for the case the stochastic process underlying the evolution of the population is a birth process. Two interesting by-products emerge from the study presented in part one; namely a combinatorial method of finding solutions to the Kolmogorov differential equations in special cases, and secondly, a set of criteria for the optimum allocation of genotypes in the host population of a host-pathogen system. The optimum allocation of genotypes in the host population is a problem of practical importance in controlling plant pathogens. In part two the theory of restricted transition probabilities developed in the companion paper is applied in finding the distribution of the time to the appearance of the first mutation for the case of a two dimensional birth process. The distribution of the time to the appearance of the first mutation is of importance in understanding the role mutation plays in the evolution of a population, particularly in the pathogen population of a host-pathogen system. The research reported in this paper was supported by the United States Atomic Energy Commission, Division of Biology and Medicine Project AT(45-1)-1729.     

Studies of Human Olfaction from the University of Pennsylvania Smell and Taste Center

This paper, presented in part as an invited lecture on the occasionof Professor E.P. Köster's retirement from Utrecht University,summarizes a large body of human studies performed at the Universityof Pennsylvania Smell and Taste Center during the last 17 years.Details of the development of standardized olfactory tests areprovided, including their validation and application in a widevariety of clinical and laboratory settings. Included are studiesrelated to transduction mechanisms in olfactory coding and factorsthat adversely influence olfactory function (e.g. age, gender,smoking, exposure to environmental chemicals, numerous diseases).A brief discussion of the strengths and weaknesses of the olfactoryvector hypothesis for neurodegenerative diseases is also presented.Chem. Senses 22: 565–586, 1997.     

Climate change and heat-related mortality in six cities Part 1: model construction and validation

Heat waves are expected to increase in frequency and magnitude with climate change. The first part of a study to produce projections of the effect of future climate change on heat-related mortality is presented. Separate city-specific empirical statistical models that quantify significant relationships between summer daily maximum temperature (T _max) and daily heat-related deaths are constructed from historical data for six cities: Boston, Budapest, Dallas, Lisbon, London, and Sydney. ‘Threshold temperatures’ above which heat-related deaths begin to occur are identified. The results demonstrate significantly lower thresholds in ‘cooler’ cities exhibiting lower mean summer temperatures than in ‘warmer’ cities exhibiting higher mean summer temperatures. Analysis of individual ‘heat waves’ illustrates that a greater proportion of mortality is due to mortality displacement in cities with less sensitive temperature–mortality relationships than in those with more sensitive relationships, and that mortality displacement is no longer a feature more than 12 days after the end of the heat wave. Validation techniques through residual and correlation analyses of modelled and observed values and comparisons with other studies indicate that the observed temperature–mortality relationships are represented well by each of the models. The models can therefore be used with confidence to examine future heat-related deaths under various climate change scenarios for the respective cities (presented in Part 2).     

The components of the proteasome system and their role in MHC class I antigen processing

By generating peptides from intracellular antigens which are then presented to T cells, the ubiquitin/26S proteasome system plays a central role in the cellular immune response. The proteolytic properties of the proteasome are adapted to the requirements of the immune system by proteasome components whose synthesis is under the control of interferon-γ. Among these are three subunits with catalytic sites that are incorporated into the enzyme complex during its de novo synthesis. Thus, the proteasome assembly pathway and the formation of immunoproteasomes play a critical regulatory role in the regulation of the proteasome's catalytic properties. In addition, interferon-γ also induces the synthesis of the proteasome activator PA28 which, as part of the so-called hybrid proteasome, exerts a more selective function in antigen presentation. Consequently, the combination of a number of regulatory events tunes the proteasome system to gain maximal efficiency in the generation of peptides with regard to their quality and quantity.     

Oligocene cold-seep carbonates from the Carpathians and their inferred relation to gas hydrates

The Krosno Formation of the Outer Carpathians is composed of synorogenic deposits laid down in the Silesian foredeep basin in front of an accretionary prism. The Oligocene shales of the Krosno Formation from Świątkowa Wielka (the Polish part of the Outer Carpathians) contain numerous authigenic carbonate rocks: concretions, a laminated limestone bed, and a carbonate build-up consisting of intraformational breccia. The application of stable carbon isotope analysis revealed that the formation of these carbonates was induced by methane oxidation. The presence of fossilized giant Beggiatoa-like filaments and large quantities of framboidal pyrite indicate that methane oxidation was microbially driven and coupled with sulfate reduction. A model of origin of these cold-seep carbonates in relation to hydrocarbon seepage is herein presented. Characteristic druses with clast-like appearance are thought to inherit their outlines from former clasts of gas hydrate that had been present within the build-up. It is proposed that thick gas hydrate deposits existed in the southern part of the Silesian basin at that time. This theory is consistent with regional, geotectonic, and palaeobathymetric data and provides a ready explanation of the major phenomena that have been recorded in the Krosno Formation.     

The importance of stroma in morphogenesis and functional activity of urogenital epithelium

Summary Urogenital morphogenesis and cytodifferentiation are presented in the context of the epithelial-stromal interaction. The essential role of stroma in these processes is reviewed. Presented in the formal symposium on Sexual Differentiation in Vitro and in Vivo at the 29th Annual Meeting of the Tissue Culture Association, Denver, Colorado, June 4–8, 1978. The study was supported in part by Grant No. PDT-8 from the American Cancer Society, and Contract Grants N01-CP-55649 and N01-CP-75875 from the National Cancer Institute.