986 resultados para 2nd Regiment of the Lincoln Militia
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Poplars consist of all species of the genus Populus, including cottonwoods, aspens, and the many interspecies hybrids in common use (Dickmann and Stuart 1983). Our working group focused on the fungal pathogens, arthropod herbivores, and weed competitors of Populus in the United States. However, bacterial and viral diseases of Populus are significant in Europe, and genetic engineering approaches toward their control or management are being studied. The key aspects of poplar biology important to understanding the use of pest resistance genes are described below.
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Blackwell Publishing Ltd. A linkage map of the Ixodes scapularis genome was constructed, based upon segregation amongst 127 loci. These included 84 random amplified polymorphic DNA (RAPD) markers, 32 Sequence-Tagged RAPD (STAR) markers, 5 cDNAs, and 5 microsatellites in 232 F1 intercross progeny from a single, field-collected P1 female. A preliminary linkage map of 616 cM was generated across 14 linkage groups with one marker every 10.8 cM. Assuming a genome size of ~ 10 9 bp, the relationship of physical to genetic distance was found to be ~ 300 kb/cM in the I. scapularis genome.
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A linkage map of the Ixodes scapularis genome was constructed based upon segregation amongst 127 loci. These included 84 random amplified polymorphic DNA (RAPD) markers, 32 Sequence-Tagged RAPD (STAR) markers, 5 cDNAs, and 5 microsatellites in 232 F1 intercross progeny from a single, field-collected P1 female. A preliminary linkage map of 616 cM was generated across 14 linkage groups with one marker every 10.8 cM. Assuming a genome size of ∼109 bp, the relationship of physical to genetic distance is ∼300 kb/cM in the I. scapularis genome.
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Covers the physical attributes (physiography, climate and vegetation) of the Brooks Range, Alaska, as well as the Numamuit Eskimo people who lived there in the 1940s and before (including information about their livelihood, history, dwellings, clothing, food, transportation and hunting implements), and includes a list and description of the mammals that lived there (including shrews, grizzly bears, foxes, wolves, martens, ermines, weasels, minks, wolverines, otters, lynxes, hares, marmots, ground squirrels, red squirrels, lemmings, voles, beavers, porcupines, moose, caribou and sheep).
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This paper investigates postgraduate students' perceptions of the Internet as an enabler of scholarship.The specific objectives of the study are: to ascertain the perception held by the postgraduate students on the Internet usage as an enabler of scholarship, and to determine what interventions are necessary to facilitate postgraduate students' adoption of the Internet as a tool for learning and research. The subjects of study are the postgraduate students of the University of Ibadan, Nigeria. A random sample of 100 students was selected with representation from each faculty of the university. A questionnaire instrument with a 12-item scale was designed and administered. Data analysis was done using the chi-square statistical method. The results show that majority of the postgraduate students have positive perceptions of the Internet as an enabler of information sourcing for learning and research. However some of these students have low self-efficacy in Internet use for information sourcing.
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In this action research study of my sixth grade mathematics class, I investigated the influence a change in my questioning tactics would have on students’ ability to determine answer reasonability to mathematics problems. During the course of my research, students were asked to explain their problem solving and solutions. Students, amongst themselves, discussed solutions given by their peers and the reasonability of those solutions. They also completed daily questionnaires that inquired about my questioning practices, and 10 students were randomly chosen to be interviewed regarding their problem solving strategies. I discovered that by placing more emphasis on the process rather than the product, students became used to questioning problem solving strategies and explaining their reasoning. I plan to maintain this practice in the future while incorporating more visual and textual explanations to support verbal explanations.
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Child maltreatment has been linked to a myriad of long-term difficulties, including trauma symptomatology. However, not all victims experience long-term distress. Thus, a burgeoning area of research focuses on factors that may impede or facilitate resiliency to the psychological correlates of child maltreatment. Specifically, the severity of the abusive acts may be associated with greater long-term difficulties. To date, however, with the exception of child sexual abuse, few studies have examined the severity of maltreatment as a risk factor in the development of trauma symptoms. In contrast, social support has been theorized to contribute to resiliency following abuse. However, to date, the majority of studies examining positive social support as a protective factor have relied on self-report measures of perceived social support, rather than observational measures of received social support. Moreover, no study to date has examined the role that negative social support (i.e, blaming, criticizing) may play in potentiating trauma symptoms among victims of child maltreatment. Because child maltreatment involves serious boundary violations by a trusted person, a marital relationship is an important domain in which to examine these constructs. That is, it may serve as an arena for the manifestation of psychological disturbances related to maltreatment. Thus, the present study examined whether observationally measured positive and negative spousal social support moderated the relationship between child maltreatment severity (i.e., sexual, physical, psychological abuse; neglect) and trauma symptomatology in women and men. Results indicated that the severity of each type of child maltreatment significantly predicted increased adult trauma symptomatology. Contrary to hypothesized outcomes, positive spousal social support did not predict decreased trauma symptomatology. However, negative spousal social support generally did predict increased trauma symptomatology. There were no consistent patterns of interactions between child maltreatment severity and either type of social support. Future directions for research will be discussed and clinical implications with regard to the intrapersonal and interpersonal functioning of child maltreatment victims will be highlighted.
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1. The crabeater seal Lobodon carcinophaga is considered to be a key species in the krill-based food web of the Southern Ocean. Reliable estimates of the abundance of this species are necessary to allow the development of multispecies, predator–prey models as a basis for management of the krill fishery in the Southern Ocean. 2. A survey of crabeater seal abundance was undertaken in 1500 000 km2 of pack-ice off east Antarctica between longitudes 64–150° E during the austral summer of 1999/2000. Sighting surveys, using double observer line transect methods, were conducted from an icebreaker and two helicopters to estimate the density of seals hauled out on the ice in survey strips. Satellite-linked dive recorders were deployed on a sample of seals to estimate the probability of seals being hauled out on the ice at the times of day when sighting surveys were conducted. Model-based inference, involving fitting a density surface, was used to infer densities in the entire survey region from estimates in the surveyed areas. 3. Crabeater seal abundance was estimated to be between 0.7 and 1.4 million animals (with 95% confidence), with the most likely estimate slightly less than 1 million. 4. Synthesis and applications. The estimation of crabeater seal abundance in Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR) management areas off east Antarctic where krill biomass has also been estimated recently provides the data necessary to begin extending from single-species to multispecies management of the krill fishery. Incorporation of all major sources of uncertainty allows a precautionary interpretation of crabeater abundance and demand for krill in keeping with CCAMLR’s precautionary approach to management. While this study focuses on the crabeater seal and management of living resources in the Southern Ocean, it has also led to technical and theoretical developments in survey methodology that have widespread potential application in ecological and resource management studies, and will contribute to a more fundamental understanding of the structure and function of the Southern Ocean ecosystem.
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Killer whale (Orcinus orca Linnaeus, 1758) abundance in the North Pacific is known only for a few populations for which extensive longitudinal data are available, with little quantitative data from more remote regions. Line-transect ship surveys were conducted in July and August of 2001–2003 in coastal waters of the western Gulf of Alaska and the Aleutian Islands. Conventional and Multiple Covariate Distance Sampling methods were used to estimate the abundance of different killer whale ecotypes, which were distinguished based upon morphological and genetic data. Abundance was calculated separately for two data sets that differed in the method by which killer whale group size data were obtained. Initial group size (IGS) data corresponded to estimates of group size at the time of first sighting, and post-encounter group size (PEGS) corresponded to estimates made after closely approaching sighted groups.
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Introduction to Biology of the Acanthocephala, edited by D.W.T. Crompton and Brent B. Nickol; Cambridge University Press, 1985.
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In practice, epizootiology deals with how parasites spread through host populations, how rapidly the spread occurs and whether or not epizootics result. Prevalence, incidence, factors that permit establishment of infection, host response to infection, parasite fecundity and methods of transfer are, therefore, aspects of epizootiology. Indeed, most aspects of a parasite could be related in sorne way to epizootiology, but many of these topics are best considered in other contexts. General patterns of transmission, adaptations that facilitate transmission, establishment of infection and occurrence of epizootics are discussed in this chapter. When life cycles are unknown, little progress can be made in understanding the epizootiological aspects of any group of parasites. At the time Meyer's monograph was completed (1933), intermediate hosts were known for only 17 species of Acanthocephala, and existing descriptions are not sufficient to permit identification of two of those. Laboratory infections of intermediate hosts had apparently been produced for only two species. Study at that time was primarily devoted to species descriptions, host and geographical distribution, structure and ontogeny. Little or nothing was known about adaptations that promote transmission and the concept of paratenic hosts was unclear. In spite of the paucity of information, Meyer (1932) summarized pathways of transmission among principal groups of hosts, visualized the relationships among life cycle patterns for the major groups of Acanthocephala, and devised models for the hypothetical origin of terrestrial life cycles from aquatic ones. Nevertheless, most of our knowledge regarding epizootiology has been recently acquired.
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The Neotropical genus Coprophanaeus Olsoufieff (1924), as classified here, comprises 38 species distributed among three subgenera (Megaphanaeus Olsoufieff, Metallophanaeus Olsoufieff, and Coprophanaeus s. str. ) and eight species groups. Keys presented help to identify supraspecific and species taxa, all of which are illustrated and diagnosed. Lectotypes are designated for Phanaeus ignecinctus Felsche and Phanaeus ohausi Felsche. Coprophanaeus corythus (Harold), formerly regarded as a subspecies of C. telamon (Erichson), assumes species status. Coprophanaeus magnoi Arnaud, described as a subspecies of C. milon (Blanchard), is raised to species status. New taxonomic interpretations result in 10 new subjective synonymies (junior synonym listed first): Phanaeus machadoi Pereira and d’Andretta = Coprophanaeus saphirinus (Perty); Phanaeus costatus Olsoufieff = Coprophanaeus cyanescens (Olsoufieff); Phanaeus worontzowi Pessôa and Lane = Coprophanaeus cyanescens (Olsoufieff); Coprophanaeus kohlmanni Arnaud = Coprophanaeus morenoi Arnaud; Coprophanaeus pluto nogueirai Arnaud = Coprophanaeus pluto (Harold); Coprophanaeus edmondsi Arnaud = Coprophanaeus conocephalus (Olsoufieff); Coprophanaeus uhleri Malý and Pokorný = Coprophanaeus chiriquensis (Olsoufieff); Coprophanaeus henryi Malý and Pokorný = Coprophanaeus gilli Arnaud; Phanaeus perseus Harold = Coprophanaeus corythus (Harold); Coprophanaeus telamon nevinsoni Arnaud and Gámez = Coprophanaeus corythus; and Coprophanaeus florenti Arnaud = Coprophanaeus ohausi (Felsche). The status of the following names remains unresolved: Phanaeus strandi Balthasar; Coprophanaeus rigoutorum Arnaud; C. terrali Arnaud; C. lichyi Arnaud; C. lecromi Arnaud; C. larseni Arnaud; and C. vazdemeloi Arnaud.
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During DNA replication the helicase (DnaB) recruits the primase (DnaG) in the replisome to initiate the polymerization of new DNA strands. DnaB is attached to the τ subunit of the clamp-loader that loads the β clamp and interconnects the core polymerases on the leading and lagging strands. The τ–DnaB−DnaG ternary complex is at the heart of the replisome and its function is likely to be modulated by a complex network of allosteric interactions. Using a stable ternary complex comprising the primase and helicase from Geobacillus stearothermophilus and the τ subunit of the clamp-loader from Bacillus subtilis we show that changes in the DnaB–τ interaction can stimulate allosterically primer synthesis by DnaG in vitro. The A550V τ mutant stimulates the primase activity more efficiently than the native protein. Truncation of the last 18 C-terminal residues of τ elicits a DnaG-stimulatory effect in vitro that appears to be suppressed in the native τ protein. Thus changes in the τ–DnaB interaction allosterically affect primer synthesis. Although these C-terminal residues of τ are not involved directly in the interaction with DnaB, they may act as a functional gateway for regulation of primer synthesis by τ-interacting components of the replisome through the τ–DnaB−DnaG pathway.
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1. The genus Echinococcus Rudolphi, 1801, is reviewed. The recorded measurements of all species are shown in tables, and their taxonomic status is discussed. 2. Three species of Echinococcus can be distinguished by morphological criteria and are considered valid: E. granulosus, E. multilocularis and E. oligarthrus. The status of E. felidis and E. patagonicus is uncertain, but both may be conspecific with E. granulosus. Six species are considered synonyms of E. granulosus: E. cameroni, E. intermedius, E. longimanubrius, E. lycaontis, E. minimus and E. ortleppi.
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A review of the distribution of Holarctic Recent mammals.