Assessing Allowable Take of Migratory Birds

ABSTRACT Legal removal of migratory birds from the wild occurs for several reasons, including subsistence, sport harvest, damage control, and the pet trade. We argue that harvest theory provides the basis for assessing the impact of authorized take, advance a simplified rendering of harvest theory known as potential biological removal as a useful starting point for assessing take, and demonstrate this approach with a case study of depredation control of black vultures (Coragyps atratus) in Virginia, USA. Based on data from the North American Breeding Bird Survey and other sources, we estimated that the black vulture population in Virginia was 91,190 (95% credible interval = 44,520-212,100) in 2006. Using a simple population model and available estimates of life-history parameters, we estimated the intrinsic rate of growth (r_max) to be in the range 7–14%, with 10.6% a plausible point estimate. For a take program to seek an equilibrium population size on the conservative side of the yield curve, the rate of take needs to be less than that which achieves a maximum sustained yield (0.5 × r_max). Based on the point estimate for r_max and using the lower 60% credible interval for population size to account for uncertainty, these conditions would be met if the take of black vultures in Virginia in 2006 was <3,533 birds. Based on regular monitoring data, allowable harvest should be adjusted annually to reflect changes in population size. To initiate discussion about how this assessment framework could be related to the laws and regulations that govern authorization of such take, we suggest that the Migratory Bird Treaty Act requires only that take of native migratory birds be sustainable in the long-term, that is, sustained harvest rate should be <r_max. Further, the ratio of desired harvest rate to 0.5 X r_max may be a useful metric for ascertaining the applicability of specific requirements of the National Environmental Protection Act.     

New theory of uterovaginal embryogenesis

Background: The explanation of uterine and vaginal embryogenesis in humans still poses many controversies, because it is difficult to assess early stages of an embryo. The literature review revealed many disagreements in Mullerian theory, inciting some authors to propose new embryological hypotheses. In the original Mullerian theory: the paramesonephral ducts form the Fallopian tubes, uterus and vagina; the mesonephral ducts regress in female embryos. Aims: The aim of this article is to investigate the development of Mullerian ducts in humans, using comparative analysis of fundamental embryological theory and various utero-vaginal anomalies. Material and methods: Between 1998 and 2015, 434 patients with various uterovaginal malformations had been operated on at the Scientific Centre of Obstetrics Gynaecology and Perynatology in Moscow. The anatomies of the uterovaginal malformations in these patients were diagnosed with ultrasound and MRI and then verified during surgical correction by laparoscopy. Results: A systematic comparison of uterovaginal malformations to those in the literature has allowed us to formulate a new theory of embryonic morphogenesis. The new theory is significantly different: ovary, ovarian ligamentum proprium, and ligamentum teres uteri derive from gonadal ridges; Fallopian tubes and vagina completely develop from mesonephral ducts. The uterus develops in the area of intersection between the mesonephral ducts with gonadal ridges by the fusion of the two. Conclusions: The new theory may to induce future embryological studies. The hypothetic possibility that the ovary and endometrium derive from the gonadal ridges could be the key to understanding the enigmatic aetiologies of extragenital and ovarian endometriosis.     

The resonance approach to the formation and structure of atoms and molecules

As shown recently, the set of electronic configurations of all chemical elements in the subshell partitioning has a four-dimensional structure. Hence, all elements can be subdivided into cycles and supercycles rather than into periods of the conventional Periodic Table. Moreover, in the plane of the principal and orbital quantum numbers there is an obvious symmetry between the hydrogen-atom spectrum (one-electron problem) and the electronic configurations of all atoms (multi-electron problem). In order to explain these phenomena, it is hypothesized that between shell electrons and nuclei protons there exists a reversible quantum-field interaction (electron + proton ↔ neutron + neutrino resonance). Even if this interaction were a rare event, it can explain the existence of 4D symmetries mentioned above. However, the model considered here is based on frequent epn interactions, taking place more often than 10¹⁵ times per second. In this case, epn resonance and resonance between such resonances are supposed to underlie the structure of all atoms and molecules. In particular, the functioning of all biological molecules, including electron transfer and enzymatic activity, is determined by resonance, resonance between resonances, hierarchy of resonances, and networks of resonances. The text was submittred by the author in english.     

On adaptation: A reduction of the Kauffman-Levin model to a problem in graph theory and its consequences

It is shown that complex adaptations are best modelled as discrete processes represented on directed weighted graphs. Such a representation captures the idea that problems of adaptation in evolutionary biology are problems in a discrete space, something that the conventional representations using continuous adaptive landscapes does not. Further, this representation allows the utilization of well-known algorithms for the computation of several biologically interesting results such as the accessibility of one allele from another by a specified number of point mutations, the accessibility of alleles at a local maximum of fitness, the accessibility of the allele with the globally maximum fitness, etc. A reduction of a model due to Kauffman and Levin to such a representation is explicitly carried out and it is shown how this reduction clarifies the biological questions that are of interest.Thanks are due to William Wimsatt, James F. Crow, and the referees for Biology and Philosophy for comments on an earlier version of this paper. Remarks by members of the audience, especially Abner Shimony, of a seminar at Boston University, February 19, 1988, were also very helpful. The diagrams were prepared with the assistance of Tracy Lubas.     

Resistance properties of the diluting segment ofAmphiuma kidney: Influence of potassium adaptation

Summary Chronic exposure to high potassium stimulates K⁺-secretory mechanisms in the diluting segment of the amphibian kidney (K⁺ adaptation). Since K⁺ net flux depends critically on the passive cell membrane permeabilities for K⁺ ions, cable analysis and K⁺-concentration step changes were applied in this nephron segment to assess the individual resistances of the epithelium and the K⁺ conductance of the luminal cell membrane. Experiments were performed in the isolated, doubly-perfused kidney of both control and K⁺-adaptedAmphiuma. In control animals transepithelial resistance was 290±27 cm², which decreased significantly to 199±17 cm² after K⁺ adaptation. The resistance in parallel of the luminal and peritubular cell membrane decreased from a control value of 157±14 to 108±6 cm² after chronic K⁺ treatment. This was paralleled by a decrease of the ratio of the luminal to peritubular cell membrane resistance from 2.5±0.1 to 1.9±0.1, respectively. Estimation of the individual cell membrane resistances reveals that the combined resistance of the luminal and peritubular cell membrane is in the same order of magnitude as the paracellular shunt resistance in diluting segments of both control and K⁺-adapted animals. The luminal cell membrane is K⁺ selective under both conditions, but the absolute luminal K⁺ conductance increases by some 60% with K⁺ adaptation. This leads to an increased back-leak of K⁺ from cell to lumen and may explain stimulated K⁺ net secretion found after chronic K⁺ loading.     

Asbestos-Mediated transfection of mammalian cell cultures

Summary The capacity of asbestos to mediate transfection was tested in a rapid and relatively simple system: picornavirus RNAs and mammalian cells in vitro. Thirteen asbestos samples, including amosite, anthophyllite, chrysotile, and crocidolite, 4 picornaviruses (poliovirus 1 and 2, echovirus 7, and encephalomyocarditis virus), and 4 cell lines (CLI, chimpanzee liver; KB, human carcinoma eta, monkey kidney; NIH 3T3, mouse embryo) were tested. The results showed that all asbestos samples mediated transfection and that all cell lines were transfectible by viral RNA with asbestos. Transfection was much greater with asbestos added to the viral RNA inoculum than to the cells before or after the RNA. Transfection was directly proportional to asbestos concentration. Initiation of transfection events was rapid, with half becoming irreversible by washing 2 min postinoculation. DNA in the inoculum strongly interfered with asbestos-mediated transfection by the RNA but was ineffective when added, with or without asbestos, to the cells before or after the inoculum. Asbestos compared with six classical “insoluble” facilitators (bentonite, calcium phosphate, chromic oxide, ferric oxide, kaolin, talc) was of intermediate rank in transfection mediation. It is hypothesized that the prominence of asbestos in carcinogenesis is due to a combination of properties, including transfection mediation as well as chromosome mutagenicity, fiber dimensions, biological durability, hydrocarbon transport, and prevalence.     

Compositional patterns in vertebrate genomes: Conservation and change in evolution

Summary The evolution of vertebrate genomes can be investigated by analyzing their regional compositional patterns, namely the compositional distributions of large DNA fragments (in the 30–100-kb size range), of coding sequences, and of their different codon positions. This approach has shown the existence of two evolutionary modes. In the conservative mode, compositional patterns are maintained over long times (many million years), in spite of the accumulation of enormous numbers of base substitutions. In the transitional, or shifting, mode, compositional patterns change into new ones over much shorter times.The conservation of compositional patterns, which has been investigated in mammalian genomes, appears to be due in part to some measure of compositional conservation in the base substitution process, and in part to negative selection acting at regional (isochore) levels in the genome and eliminating deviations from a narrow range of values, presumably corresponding to optimal functional properties. On the other hand, shifts of compositional patterns, such as those that occurred between cold-blooded and warm-blooded vertebrates, appear to be due essentially to both negative and positive selection again operating at the isochore level, largely under the influence of changes in environmental conditions, and possibly taking advantage of mutational biases in the replication/repair enzymes and/or in the enzyme make-up of nucleotide precursor pools. Other events (like translocations and changes in chromosomal structure) also play a role in the transitional mode of genome evolution.The present findings (1) indicate that isochores, which correspond to the DNA segments of individual or contiguous chromatin domains, represent selection units in the vertebrate genome; and (2) shed new light on the selectionist-neutralist controversy.This work was presented at the EMBO Workshop on Evolution (Cambridge, UK, 4–6 July 1988) and at the 16th International Congress of Genetics (Toronto, Canada, 20–27 August 1988)     

数学模型与自然保护科学

日益加剧的人类干扰和景观破碎化已危及全球的生物多样性。自然保护成为人类所面临的最重要也最富有挑战性的任务。指导这一实践的理论和原则极为需要。本文试图综述与自然保护科学有关的几个学科在理论和实际研究(尤其是模型)方面的近期成果以及发展趋势,从而提出自然保护模型的发展方向。文中涉猎基于不同方法论、不同组织水平的模型,并对数学模型在自然保护科学中的作用和实用性加以讨论。     

Does biocatalysis involve inhomogeneous kinetics?

Biocatalytic reactions can occur according to two very different mechanisms: homogeneous, which is described by standard transition state theory (TST) and its modifications, and inhomogeneous (polychromatic), which is characteristic for some of the charge-transfer reactions in liquids and amorphous solids. While most data published on enzyme reactions are interpreted on the basis of homogeneous kinetics, the important recent findings suggest the involvement of inhomogeneous kinetics mechanism.