Mappings of the plane that simulate prey-predator systems

A prey-predator system that is spatially dependent is built around the familiar logistic equation. The result is a set of coupled integro-differential equations. If at least one of the populations reproduces periodically in a time that is short to other characteristic times, these equations can be transformed to a set of coupled maps, each map representing a spatial point. Various models are developed that include predator ranging as well predator migration via diffusion. In two dimensions the coupling among the spatial points will have the symmetry of the regular polyhedra if the infinite plane is viewed in polar coordinates, or toroidal symmetry if periodic boundary conditions are imposed. Numerical examples are given. Depending on the value of the parameters and on the initial conditions the system can oscillate in a variety of different spatial modes, giving rise to unusual bifurcation portraits, or it can behave chaotically. The solutions show that a patchy distribution of population is more stable against the influences of environmental noise than is a smoothly distributed population. The numerical results in two dimensions are in constrast with the results of a previous study in one dimension.     

Characterization and cloning of extrachromosomal DNA from filamentous cyanobacteria

Abstract Physical maps of cryptic plasmids from the filamentous cyanobacteria Anabaena variabilis PCC7118 (pGL1: 3.6 MDa), Nostoc PCC6705 (pGL2: 2.6 MDa) and Plectonema PCC6306 (pGL3: 0.95 MDa) were generated. Selectable markers were introduced onto pGL2 and pGL3 by fusing them to the vector pBR328, using their single restriction sites for Cla I. The recombinant plasmids generated were characterised with respect to the orientation of the insert and the single sites for restriction endonucleases which they possess. The stability of pGL1 and of the two recombinant plasmids in culture was investigated and a method for isolating larger cyanobacterial plasmids (> 20 MDa) was devised.     

The mosquitoes of Finland: updated distributions and bionomics

Mosquitoes (Diptera: Culicidae) were collected in Finland between 2012 and 2018 to determine the species present and their distributions. In total, 52 466 specimens from 1031 collections formed the basis for the preparation of distribution maps for each of the 40 species that were collected. Anopheles maculipennis s.s., An. claviger, Aedes geminus and Ochlerotatus sticticus are confirmed on mainland Finland after previous records were uncertain or absent. Coquillettidia richiardii, Culiseta morsitans, Cs. ochroptera, Culex territans, Cx. torrentium, Oc. leucomelas, Oc. nigrinus, Oc. pullatus and Oc. punctodes occur more widely than previously reported. Three species, Ae. rossicus, Cs. subochrea and Oc. cyprius were not collected, although Ae. rossicus was subsequently found in Lapland by another researcher. No invasive species were collected. Ochlerotatus communis, an aggressive biter, was the most commonly encountered species. Larval collection data suggest that several species may have up to three generations per year in Finland, with Cx. torrentium and Cx. pipiens having at least two, and Oc. communis and Oc. punctor regularly found as larvae across the summer. These data, especially when coupled with historical records, are vital for monitoring species which have significant vector potential, particularly when faced with a warming climate.     

Physical molecular maps of wheat chromosomes

In bread wheat, a set of 527 simple sequence repeats (SSRs) were tried on 164 deletion lines, leading to a successful mapping of 270 SSRs on 313 loci covering all 21 chromosomes. A maximum of 119 loci (38%) were located on B subgenome, and a minimum of 90 loci (29%) mapped on D subgenome. Similarly, homoeologous group 7 carried a maximum of 61 loci (19%), and group 4 carried a minimum of 22 loci (7%). Of the cited 270 SSRs, 39 had multiple loci, but only eight of these detected homoeologous loci. Linear order of loci in physical maps largely corresponded with those in the genetic maps. Apparently, distances between each of only 26 pairs of loci significantly differed from the corresponding distances on genetic maps. Some loci, which were genetically mapped close to the centromere, were physically located distally, while other loci that were mapped distally in the genetic maps were located in the proximal bins in the physical maps. This suggested that although the linear order of the loci was largely conserved, variation does exist between genetic and physical distances.Electronic Supplementary Material Supplementary material is available for this article at .     

The current knowledge on centipedes (Chilopoda) in Slovenia: faunistic and ecological records from a national database

In spite of Slovenia’s very high biodiversity, it has only a few animal groups that have been significantly investigated and are well known in this area. Slovenian researchers have studied only about half of the species known to be living in the country (Mršić 1997), but among well investigated species are centipedes. All available data about centipedes in Slovenia collected from 1921 to 2014 have been consolidated and constitute a general electronic database called “CHILOBIO”, which was created to provide an easy overview of the Slovenian centipede fauna and to allow entry and interpretation of new data collected in future research. The level of investigation has been studied with this database, in conjunction with a geographic information system (GIS). In the study period, 109 species were identified from 350 localities in 109 of the 236 UTM 10 × 10 km quadrants which cover the study area. The south-central part of the country has been the subject of the best investigations, whereas there is an absence of data from the south-eastern, eastern and north-eastern regions The highest number of species (52) has been recorded near the Iška valley (Central Slovenia, quadrant VL68). In 48% of the UTM quadrants investigated fewer than 10 species were recorded and just 5 species were found in one locality. Seventeen species were reported only in the Dinaric region, 4 in the Prealpine-subpannonian region and 7 in the Primorska-submediterranean region.     

Proteomic analysis of anti-angiogenic effects by a combined treatment with vinblastine and rapamycin in an endothelial cell line

Angiogenesis controls the new blood supply routes into the tumor mass via the host endothelial cells (ECs). In this study, the EA.hy926 endothelial cell line has been treated with vinblastine (VBL) and rapamycin (RAP), both separately and in combination at low doses. Recently, we demonstrated the synergistic antiangiogenic effects of a combination of VBL and RAP at very low doses in vitro and in vivo. Herein, we confirm the ability of this combined treatment to statistically inhibit the proliferation of ECs, in a synergistic manner, by inducing apoptosis. The aim of this study was to substantiate these findings at the protein level. Differential proteomic analysis was performed on untreated control cells, treated with VBL, incubated with RAP, or subjected to a drug combination. Differentially expressed 113 polypeptide chains were visualized and 65 were identified via MALDI-TOF analysis. Some of the regulated proteins are involved in the processes of angiogenesis, proliferation, migration, and apoptosis. The down-modulation of ATP synthase, annexin A2, heat shock p70, glucose-6-phosphate dehydrogenase, vasodilator-stimulated phosphoprotein, proteasome 26S, tryptophanyl-tRNA synthetase, and stathmin/OP18, as well as the up-modulation of carbonyl reductase, Rho-GDI, and histone H1.0 correlates with the synergistic antiangiogenic activity of VBL and RAP.     

RFLP-based genetic map of the homoeologous group 3 chromosomes of wheat and rye

Summary Genetic maps of chromosomes 3A, 3B and 3D of wheat and 3R of rye were developed using 22 DNA probes and two isozyme marker systems. Analysis of the 49 loci mapped showed extreme clustering around the centromere in all four maps, with large gaps in the distal chromosome regions, which is interpreted as being due to strong localisation of recombination towards the ends of the wheat and rye chromosomes. In the centromeric regions gene orders are highly conserved between the three wheat genomes and the rye genome. However, the unpredictable behaviour of the DNA clones that map in distal chromosome locations may indicate that the genomes are diverging most rapidly in the regions of higher recombination. A comparison of cDNA and genomic probes showed the latter to be much more efficient for revealing RFLP. Some classes of gDNA clones, i.e. chromosome-specific sequences and those hybridizing in a non-homoeologous manner, were seen to be most polymorphic. Correlations between map locations and RFLP levels showed no clear relationship. In addition to anonymous DNA clones, the locations of known function clones, sedoheptulose-1,7-bisphosphatase (XSbp), carboxypeptidase I (XCxp1) and a bZIP protein (XEmbp), were ascertained along with those for two isozyme loci, Mal-1 and Est-5.     

构建分子标记连锁图谱的图论构图方法

结合统计学、遗传学和图论原理,建立了一种新的分子标记连锁图谱构建的方法,即图论构图法．应用这种方法,从７７个家蚕ＲＡＰＤ标记位点中构建了７个标记位点的两个连锁群．与ＭＡＰＭＡＲＫＥＲ程序所构建的结果相比表明,图论构图法具有更为可靠的构图效果．     

自然哺乳长颈鹿的幼仔行为研究

对成都动物园2005年和2008年出生长颈鹿幼仔在母兽哺乳情况下的1月龄内幼仔行为进行了观察和分析.发现幼长颈鹿的主要行为有卧、走、站、吃奶、跑等,其中卧和站的行为分别占全天时间的61.7%和32.3%;幼长颈鹿在10 d左右开始学习采食青草,4周龄时明显能吃到一些青草.     

Animal Life in Caves

This is an interdisciplinary lesson designed for middle school students studying landforms and geological processes. Students create a two-dimensional topographic map from a three-dimensional landform that they create using clay. Students then use other groups’ topographic maps to re-create landforms. Following this, students explore some basic ideas about how landforms take shape and how they can change over time. As students work through three distinct learning-cycle phases of concept exploration, introduction, and application, they use art, language arts, and mathematical skills to strengthen or form new science and social studies concepts.     

概念图在医学微生物学教学中的应用

概念图已成为各种教育背景下的学习工具,通过概念图可以构建学生的知识结构、促进学生批判性思维的发展和对知识的理解。本文初步探讨了概念图在医学微生物学教学准备、教学实施及教学评价等方面的有效应用。     

A simulation study on Nei and Li's model for estimating DNA divergence from restriction enzyme maps

Summary A simulation study has been conducted to check the accuracy of Nei and Li's (1979) formulas for the mean and variance of the proportion (S) of identical restriction sites between two DNA sequences and for estimating the mean and variance of the number () of base substitutions per nucleotide site between two DNA sequences. The results show that these formulas are quite accurate as long as the probability of S becoming zero is negligibly small. In addition to the simulation, approximate formulas have also been obtained for the probability for S to become zero at time t and for the contribution to S due to parallel mutation.     

Optogenetic fUSI for brain-wide mapping of neural activity mediating collicular-dependent behaviors

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Homoeologous relationships of rice, wheat and maize chromosomes

A set of cDNA clones, which had previously been mapped onto wheat chromosomes, was genetically mapped onto the chromosomes of rice. The resulting comparative maps make it possible to estimate the degree of linkage conservation between these two species. A number of chromosomal rearrangements, some of which must have involved interchromosomal translocations, differentiate the rice and wheat genomes. However, synteny of a large proportion of the loci appears to be conserved between the two species. The results of this study, combined with those from a recently published comparative map of the rice and maize genomes, suggest that rice, wheat and maize share extensive homoeologies in a number of regions in their genomes. Some chromosomes (e.g. chromosome 4 in rice, chromosomes 2 and 2S in wheat and maize, respectively) may have escaped major rearrangement since the divergence of these species from their last common ancestor. Comparative maps for rice, wheat and maize should make it possible to begin uniting the genetics of these species and allow for transfer of mapping information (including centromere positions) and molecular marker resources (e.g. RFLP probes) between species. In addition, such maps should shed light on the nature of chromosome evolution that accompanied the radiation of grasses in the early stages of plant diversification.     

Effects of visitors and cage changes on the behaviors of mangabeys

Three groups of golden-bellied mangabeys were studied to determine the effects of visitors and cage changes on their aggressive displays, grooming and sexual behavior, and play. Assessments of changes in behavior were made by comparing categorized observer comments. Animals moved to cages having more visitors increased their aggressive displays toward people, decreased their aggressive displays toward other species in neighboring cages, and increased their withingroup aggression. On the other hand, grooming, sexual behavior, and play increased after cage changes regardless of numbers of visitors. The view that it is the pattern of behavior changes in enrichment that is important in assessment of attempted enrichment was supported. Aggressive and affiliative behaviors are affected quite differently by different environmental stimuli in the zoo.     

Assessing temporal scales and patterns in time series: Comparing methods based on redundancy analysis

Time-series modelling techniques are powerful tools for studying temporal scaling structures and dynamics present in ecological and other complex systems and are gaining popularity for assessing resilience quantitatively. Among other methods, canonical ordinations based on redundancy analysis are increasingly used for determining temporal scaling patterns that are inherent in ecological data. However, modelling outcomes and thus inference about ecological dynamics and resilience may vary depending on the approaches used. In this study, we compare the statistical performance, logical consistency and information content of two approaches: (i) asymmetric eigenvector maps (AEM) that account for linear trends and (ii) symmetric distance-based Moran's eigenvector maps (MEM), which requires detrending of raw data to remove linear trends prior to analysis. Our comparison is done using long-term water quality data (25 years) from three Swedish lakes. This data set therefore provides the opportunity for assessing how the modelling approach used affects performance and inference in time series modelling. We found that AEM models had consistently more explanatory power than MEM, and in two out of three lakes AEM extracted one more temporal scale than MEM. The scale-specific patterns detected by AEM and MEM were uncorrelated. Also individual water quality variables explaining these patterns differed between methods, suggesting that inferences about systems dynamics are dependent on modelling approach. These findings suggest that AEM might be more suitable for assessing dynamics in time series analysis compared to MEM when temporal trends are relevant. The AEM approach is logically consistent with temporal autocorrelation where earlier conditions can influence later conditions but not vice versa. The symmetric MEM approach, which ignores the asymmetric nature of time, might be suitable for addressing specific questions about the importance of correlations in fluctuation patterns where there are no confounding elements of linear trends or a need to assess causality.     

人乙型肝炎病毒(HBV)adr亚型基因组的多态性

由乙型肝炎adr亚型病毒(HBVadr)携带者26人的混合血清,得到了HBVadr基因组克隆株(PADR)158株,对这些克隆株进行四种限制性内切酶(BglⅡ,HindⅢ,PstⅠ,XhoⅠ)切点测定,并对其中S株的13种限制性内切酶图谱进行比较研究,发现同为adr亚型病毒,其基因组的限制性酶切图谱存在差异。另外,通过HindⅢ)切点得到的12个克隆株(PADR-H),也进行了酶切图谱分析。在这170个克隆株中,已经发现了5种类型的HBVadr基因组限制性酶切图谱,其中有6种酶(AvaⅠ,EglⅠ,BglⅡ,HincⅡ,HindⅢ,HpaⅠ)的7个变异点。本文报道了HBVadr基因组的多态性现象。     

An RFLP-based genetic map of pearl millet (Pennisetum glaucum)

Analysis of a sample of diverse pearl millet genotypes with 200 genomic DNA probes revealed this crop species to be extremely polymorphic. Among these genotypes, 85% of probes detected polymorphism using only two restriction enzymes, with an average pair-wise polymorphism between all of the probe-enzyme combinations of 56%. Two crosses were employed to construct an RFLP-based genetic map. In an intervarietal F₂ population, derived from a single F₁ plant, 181 loci were placed on a linkage map. The total length of this map, which comprised seven linkage groups, was 303 cM and the average map distance between loci was about 2 cM, although a few intervals in excess of 10 cM were present at the ends of a few linkage groups. Very few clones, including those which hybridized to more than one copy, detected more than one locus in the pearl millet genome. The analysis was complicated initially because 83 of the 181 loci mapped to a single linkage group. Analysis of a second cross identified a probable translocation breakpoint in the middle of this large linkage group.     

Coarse analysis of collective motion with different communication mechanisms

We study the effects of a signalling constraint on an individual-based model of self-organizing group formation using a coarse analysis framework. This involves using an automated data-driven technique which defines a diffusion process on the graph of a sample dataset formed from a representative stationary simulation. The eigenvectors of the graph Laplacian are used to construct 'diffusion-map' coordinates which provide a geometrically meaningful low-dimensional representation of the dataset. We show that, for the parameter regime studied, the second principal eigenvector provides a sufficient representation of the dataset and use it as a coarse observable. This allows the computation of coarse bifurcation diagrams, which are used to compare the effects of the signalling constraint on the population-level behavior of the model.