358 research outputs found
Terahertz echoes reveal the inhomogeneity of aqueous salt solutions
The structural and dynamical properties of water are known to be affected by ion solvation. However, a consistent molecular picture that describes how and to what extent ions perturb the water structure is still missing. Here we apply 2D Ramanâterahertz spectroscopy to investigate the impact of monatomic cations on the relaxation dynamics of the hydrogen-bond network in aqueous salt solutions. The inherent ability of multidimensional spectroscopy to deconvolute heterogeneous relaxation dynamics is used to reveal the correlation between the inhomogeneity of the collective intermolecular hydrogen-bond modes and the viscosity of a salt solution. Specifically, we demonstrate that the relaxation time along the echo direction t1â=ât2 correlates with the capability of a given cation to âstructureâ water. Moreover, we provide evidence that the echo originates from the waterâwater modes, and not the waterâcation modes, which implies that cations can structure the hydrogen-bond network to a certain extent
A tool for sustainability impact assessment (ToSIA)of forest-wood chains linked with a database of sustainability indicators collected within the EFORWOOD project
Within the EFORWOOD project new approaches to assess the sustainability impacts of forest-wood chains (FWC) using indicators of environmental, social and economic sustainability were developed
14-06 Development of Safety Performance Functions and Other Decision Support Tools to Assess Pedestrian and Bicycle Safety
A field study was performed at 40 uncontrolled midblock crosswalks and 26 signalized intersections on low-speed roadways selected from the areas surrounding three major urban college campuses across lower Michigan. An array of existing traffic control devices existed at the study sites, including various crosswalk marking strategies, along with additional treatments, such as pedestrian hybrid beacons (PHBs), rectangular rapid-flashing beacons (RRFBs) and single in-street R1-6 signs. The sites also collectively included a diverse set of roadway and traffic characteristics, including crossing widths, number of lanes, and median presence, along with vehicular, pedestrian, and bicyclist volumes. Three primary evaluations were performed for the midblock segments and signalized intersection study sites, including: driver yielding compliance, vehicle-pedestrian conflicts, and non-motorized traffic crash data. The yielding compliance study found that the type of crosswalk treatment has a strong influence over driver yielding compliance. While yielding compliance improves substantially when crosswalk markings are utilized, the highest compliance rates are achieved when an additional enhancement device (i.e., RRFB, PHB, or R1-6 sign), is also provided. To supplement small crash sample sizes at the study sites, Michigan statewide pedestrian and bicyclist crash data were collected and utilized to develop safety performance functions (SPFs) and other methods for predicting pedestrian and bicyclist crashes at road segments and intersections. Because pedestrian and bicyclist volumes were not available statewide, each model was developed for pedestrian and bicycle crashes based solely on vehicular AADT. In general, the models showed that pedestrian and bicycle crashes tend to increase with increasing traffic volumes. However, even in the highest volume cases, only a fraction of crashes involved a pedestrian or bicyclist. Pedestrian and bicycle crashes were further estimated based on the respective proportion of the Michigan specific SPF models for total crashes. The primary limitation towards prediction of pedestrian and bicycle crashes is the lack of a reliable exposure data to represent the amount of pedestrian or bicyclist activity on a given segment or intersection
Narrow genetic basis for the Australian dingo confirmed through analysis of paternal ancestry
The dingo (Canis lupus dingo) is an iconic animal in the native culture of Australia, but archaeological and molecular records indicate a relatively recent history on the continent. Studies of mitochondrial DNA (mtDNA) imply that the current dingo population was founded by a small population of already tamed dogs from Southeast Asia. However, the maternal genetic data might give a unilateral picture, and the gene pool has yet to be screened for paternal ancestry. We sequenced 14,437Â bp of the Y-chromosome (Y-chr) from two dingoes and one New Guinea Singing Dog (NGSD). This positioned dingo and NGSD within the domestic dog Y-chr phylogeny, and produced one haplotype not detected before. With this data, we characterized 47 male dingoes in 30 Y-chr single-nucleotide polymorphism sites using protease-mediated allele-specific extension technology. Only two haplotypes, H3 and H60, were found among the dingoes, at frequencies of 68.1 and 31.9Â %, respectively, compared to 27 haplotypes previously established in the domestic dog. While H3 is common among Southeast Asian dogs, H60 was specifically found in dingoes and the NGSD, but was related to Southeast Asian dog Y-chr haplotypes. H3 and H60 were observed exclusively in the western and eastern parts of Australia, respectively, but had a common range in Southeast. Thus, the Y-chr diversity was very low, similar to previous observations for d-loop mtDNA. Overall genetic evidence suggests a very restricted introduction of the first dingoes into Australia, possibly from New Guinea. This study further confirms the dingo as an isolated feral dog. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10709-012-9658-5) contains supplementary material, which is available to authorized users
Dog Y chromosomal DNA sequence: identification, sequencing and SNP discovery
BACKGROUND: Population genetic studies of dogs have so far mainly been based on analysis of mitochondrial DNA, describing only the history of female dogs. To get a picture of the male history, as well as a second independent marker, there is a need for studies of biallelic Y-chromosome polymorphisms. However, there are no biallelic polymorphisms reported, and only 3200 bp of non-repetitive dog Y-chromosome sequence deposited in GenBank, necessitating the identification of dog Y chromosome sequence and the search for polymorphisms therein. The genome has been only partially sequenced for one male dog, disallowing mapping of the sequence into specific chromosomes. However, by comparing the male genome sequence to the complete female dog genome sequence, candidate Y-chromosome sequence may be identified by exclusion. RESULTS: The male dog genome sequence was analysed by Blast search against the human genome to identify sequences with a best match to the human Y chromosome and to the female dog genome to identify those absent in the female genome. Candidate sequences were then tested for male specificity by PCR of five male and five female dogs. 32 sequences from the male genome, with a total length of 24 kbp, were identified as male specific, based on a match to the human Y chromosome, absence in the female dog genome and male specific PCR results. 14437 bp were then sequenced for 10 male dogs originating from Europe, Southwest Asia, Siberia, East Asia, Africa and America. Nine haplotypes were found, which were defined by 14 substitutions. The genetic distance between the haplotypes indicates that they originate from at least five wolf haplotypes. There was no obvious trend in the geographic distribution of the haplotypes. CONCLUSION: We have identified 24159 bp of dog Y-chromosome sequence to be used for population genetic studies. We sequenced 14437 bp in a worldwide collection of dogs, identifying 14 SNPs for future SNP analyses, and giving a first description of the dog Y-chromosome phylogeny
Genetic relationship between Kangal, Akbash and other dog populations
Kangal and Akbash dogs are the two well-known shepherd dog breeds in Turkey. In order to contribute to the understanding of the genetic relationship between Kangal dogs, Akbash dogs and the dogs from different regions of Eurasia, 585 base pair (bp) segment of mitochondrial DNA (mtDNA) control region was sequenced from Kangals and Akbashes. Sequences of the Kangal and Akbash dogs examined in the present study were comparatively examined with those of previous studies on dogs. Consensus neighbour-joining tree with bootstrapping, which is constructed based on pairwise Fst values between populations, indicated that Kangal dogs and Akbash dogs are on different branches of the tree. Furthermore, the nodes of these branches were supported with high bootstrap values. In conclusion, the present study indicated that Kangal and Akbash dogs might have descended maternally from different origins along the evolutionary history of domestic dogs
Transportation Safety Performance of US Bus Transit Agencies and Population Density: A Cross-Sectional Analysis (2008-2014)
The paper examines the transportation safety performance of transit agencies providing public bus service in the US by using data from the National Transit Database (NTD)
Uses NTD data for a seven-year period from 2008 to 2014 âą 3,853 observations for 651 public transportation agencies in 50 states
Seven types of bus transit fatalities and injuries (including passengers, operators, pedestrians, bicyclists)
Main explanatory variable: urban density obtained from the US Census figures
Other explanatory variables: total agency revenue miles, unlinked passenger trips, agency fleet size, and urban populatio
Phylogeny of Iridaceae Subfamily Crocoideae Based on a Combined Multigene Plastid DNA Analysis
The phylogeny of Crocoideae, the largest of four subfamilies currently recognized in Tridaceae, has eluded resolution until sequences of two more plastid DNA regions were added here to a previously published matrix containing sequences from four DNA plastid regions. Sister to the core Nivenioideae, the woody Klattia, Nivenia, and Witsenia, Crocoideae are a climax group in lridaceae, comprising some 995 species, slightly more than half of the total in the family. Synapomorphies of Crocoideae include pollen exine perforate, pollen aperture operculate, ovule campylotropous (or hypotropous), root xylem vessels with simple perforations, cormous rootstock, inflorescence a spike, and plants deciduous. The six DNA region analysis here that includes examples of 27 of the 28 genera of the subfamily shows the southern African Tritoniopsis sister to the remaining genera, which resolve into four well-supported clusters (bootstrap support \u3e85%). Each of these major clades is treated as a tribe, the synapomorphies of which are discussed in light of the molecular phylogenetic analyses. Original embryological and seed developmental studies largely support the tribal classification. Tritoniopsideae alone has the inner floral bracts not forked apically, and a hypotropous ovule, while this tribe and Watsonieae have axillary corm development. The remaining three tribes have apical corm development, and together with Watsonieae have a campylotropous ovule, and the inner layer of the inner integument crushed at maturity
Differential gene expression in femoral bone from red junglefowl and domestic chicken, differing for bone phenotypic traits
<p>Abstract</p> <p>Background</p> <p>Osteoporosis is frequently observed among aging hens from egg-producing strains (layers) of domestic chicken. White Leghorn (WL) has been intensively selected for egg production and it manifests striking phenotypic differences for a number of traits including several bone phenotypes in comparison with the wild ancestor of chicken, the red junglefowl (RJ). Previously, we have identified four Quantitative Trait Loci (QTL) affecting bone mineral density and bone strength in an intercross between RJ and WL. With the aim of further elucidating the genetic basis of bone traits in chicken, we have now utilized cDNA-microarray technology in order to compare global RNA-expression in femoral bone from adult RJ and WL (five of each sex and population).</p> <p>Results</p> <p>When contrasting microarray data for all WL-individuals to that of all RJ-individuals we observed differential expression (False discovery rate adjusted p-values < 0.015) for 604 microarray probes. In corresponding male and female contrasts, differential expression was observed for 410 and 270 probes, respectively. Altogether, the three contrasts between WL and RJ revealed differential expression of 779 unique transcripts, 57 of which are located to previously identified QTL-regions for bone traits. Some differentially expressed genes have previously been attributed roles in bone metabolism and these were: WNT inhibitory factor 1 (WIF1), WD repeat-containing protein 5 (WDR5) and Syndecan 3 (SDC3). Among differentially expressed transcripts, those encoding structural ribosomal proteins were highly enriched and all 15 had lower expression in WL.</p> <p>Conclusion</p> <p>We report the identification of 779 differentially expressed transcripts, several residing within QTL-regions for bone traits. Among differentially expressed transcripts, those encoding structural ribosomal proteins were highly enriched and all had lower expression levels in WL. In addition, transcripts encoding four translation initiation and translation elongation factor proteins also had lower expression levels in WL, possibly indicating perturbation of protein biosynthesis pathways between the two populations. Information derived from this study could be relevant to the bone research field and may also aid in further inference of genetic changes accompanying animal domestication.</p
Origin of mitochondrial DNA diversity of domestic yaks
BACKGROUND: The domestication of plants and animals was extremely important anthropologically. Previous studies have revealed a general tendency for populations of livestock species to include deeply divergent maternal lineages, indicating that they were domesticated in multiple, independent events from genetically discrete wild populations. However, in water buffalo, there are suggestions that a similar deep maternal bifurcation may have originated from a single population. These hypotheses have rarely been rigorously tested because of a lack of sufficient wild samples. To investigate the origin of the domestic yak (Poephagus grunnies), we analyzed 637 bp of maternal inherited mtDNA from 13 wild yaks (including eight wild yaks from a small population in west Qinghai) and 250 domesticated yaks from major herding regions. RESULTS: The domestic yak populations had two deeply divergent phylogenetic groups with a divergence time of > 100,000 yrs BP. We here show that haplotypes clustering with two deeply divergent maternal lineages in domesticated yaks occur in a single, small, wild population. This finding suggests that all domestic yaks are derived from a single wild gene pool. However, there is no clear correlation of the mtDNA phylogenetic clades and the 10 morphological types of sampled yaks indicating that the latter diversified recently. Relatively high diversity was found in Qinghai and Tibet around the current wild distribution, in accordance with previous suggestions that the earliest domestications occurred in this region. Conventional molecular clock estimation led to an unrealistic early dating of the start of the domestication. However, Bayesian estimation of the coalescence time allowing a relaxation of the mutation rate are better in agreement with a domestication during the Holocene as supported by archeological records. CONCLUSION: The information gathered here and the previous studies of other animals show that the demographic histories of domestication of livestock species were highly diverse despite the common general feature of deeply divergent maternal lineages. The results further suggest that domestication of local wild prey ungulate animals was a common occurrence during the development of human civilization following the postglacial colonization in different locations of the world, including the high, arid Qinghai-Tibetan Plateau
- âŠ