82 research outputs found
Retrieval of atmospheric static stability from MST radar return signal power
International audienceAn empirical technique for retrieving profiles of the square of the Brunt-VÀisÀlÀ frequency, ?B2, from MST radar return signal power is presented. The validity of the technique, which is applied over the altitude range 1.0-15.7km, is limited to those altitudes at which the humidity contributions to the mean vertical gradient of generalised potential refractive index, M, can be ignored. Although this is commonly assumed to be the case above the first few kilometres of the atmosphere, it is shown that humidity contributions can be significant right up to the tropopause level. In specific circumstances, however, the technique is valid over large sections of the troposphere. Comparisons of radar- and (balloon-borne) radiosonde-derived ?B2 profiles are typically quantitatively and qualitatively well matched. However, the horizontal separation between the radar and the radiosondes (which were launched at the radar site) increases with increasing altitude. Under conditions of mountain wave activity, which can be highly localised, large discrepancies can occur at lower-stratospheric altitudes. This demonstrates the fact that radiosonde observations cannot necessarily be assumed to be representative of the atmosphere above the launch site
Genetic evaluation of behaviour in dogs
A dog's behavioural characteristics are important for the dog, for the dog owner and for society as a whole. Behavioural traits can be changed by breeding, but to be effective when selecting breeding animals, good methods for measuring behaviour are essential. The aim of this thesis was to provide information on a number of dog behavioural measurement methods regarding their potential to be used for genetic evaluation: the Herding Trait Characterisation, the Swedish and Norwegian English Setter field trials, the Swedish Armed Forces temperament test, the Dog Mentality Assessment (DMA), and an extended version of the Canine Behavioral Assessment and Research Questionnaire. The aim was also to advance our understanding of factors affecting the usefulness of behavioural measurements for breeding purposes.
Average heritabilities for behavioural variables (items) within measurement method ranged from 0.1 to 0.3, and the items were markedly influenced by systematic environ-mental effects. All studied measurement methods can be used for selection of breeding animals, but selection based on individual performance is suboptimal. Using BLUP breeding values would substantially increase accuracy of selection and the potential genetic progress and is therefore recommended. Rough Collie results from DMA showed strong genetic correlations with important everyday life traits as described by dog owners in the questionnaire. Therefore, in order to improve everyday life behaviour in Rough Collie, DMA breeding values for relevant traits should be used for selection.
The results indicated that from a heritability perspective, behavioural measurements should be objective rather than subjective, and neutral rather than passing value judgments. Collaboration between countries within breed is also advised because a joint genetic evaluation increases the number of selection candidates, and may also increase breeding value accuracies rather dramatically, as was shown for the English Setter field trial results from Sweden and Norway.
For half of the studied methods, the measured items were summarized into composite traits. Heritability estimates for composite traits were higher than the average of the items used for creating these traits. Because the composite traits also can be expected to be more stable over time and between situations, it would be advisable to use them as selection traits
Analyser av MT frÄn ett avelsperspektiv
I denna rapport redovisas genetiska analyser av SBKs nya mentaltest (MT), det vill sÀga den version av MT som varit i bruk sedan 2007, och av gamla MT (den version som gÀllde till och med 2006) och MH (den version som gÀllt sedan 1997) för raserna schÀfer, rottweiler, boxer och hovawart.
Av de 33 beteendemÄtten frÄn MH kan 22 sammanfattas i de fem underliggande egenskaperna Lekfullhet, Nyfikenhet/OrÀdsla, Jaktintresse, Socialitet och Aggressivitet. Fem av de tio mÄtten i gamla MT gÄr att sammanfatta i de tvÄ underliggande egenskaperna SjÀlvtillit och Aggressivitet. För nya MT gÄr 20 av de 24 mÄtten att sammanfatta i sex underliggande egenskaper: Gripa-hÄlla-dra, SjÀlvtillit, Engagemang, Jaktlust, Samarbetsvilja och Socialitet.
Arvbarheterna för de 33, 10 respektive 24 beteendemÄtten frÄn MH och gamla och nya MT varierar frÄn ungefÀr 5-30 procent, och för de underliggande egenskaperna frÄn 10-40 procent. RÀknat som genomsnitt över alla beteendemÄtt inom respektive testform visar gamla MT högre arvbarheter Àn MH, och nya MT visar i sin tur högre arvbarheter Àn gamla MT. I de flesta fall Àr arvbarheterna för lÄga för att selektion av avelsdjur baserad pÄ fenotyp (sÄ kallad individselektion) ska vara effektiv. För att komma rimligt snabbt framÄt i avelsarbetet mÄste man dÀrför börja anvÀnda insamlade testdata frÄn MH och MT för att skatta sÄ kallade avelsvÀrden eller mentalindex att basera selektionen av avelsdjur pÄ.
De genetiska korrelationerna mellan de olika testformerna visar att nya MT rent genetiskt tycks fÄnga "allt" som mÀttes/mÀts i gamla MT och MH, och i tillÀgg ytterligare nÄgra egenskaper (de underliggande egenskaperna Gripa-HÄlla-Dra och Samarbetsvilja frÄn nya MT mÀttes inte i gamla MT, och beteendemÄttet Socialt samspel frÄn nya MT mÀts inte i MH). I kombination med det faktum att arvbarheterna i de flesta fall Àr likvÀrdiga eller nÄgot högre i nya MT jÀmfört med MH och gamla MT tyder detta pÄ att nya MT ur ett avelsperspektiv Àr en minst lika bra testform.
Det kan mycket vÀl hÀnda att förÀndringar behöver göras i nya MT (detta Àr inget som studerats inom ramen för denna rapport). Vad de redovisade analyserna emellertid visar Àr att nya MT jÀmfört med MH och gamla MT Àr ett vÀl sÄ bra avelsverktyg och att arbarheterna Àr tillrÀckligt höga för att testen ska kunna anvÀndas för avelsÀndamÄl. DÀrför Àr det viktigt att innan annat Àn mindre justeringar genomförs göra ordentliga analyser av nya MT. Om man kommer fram till att mer genomgripande förÀndringar Àr nödvÀndiga mÄste sÀkerstÀllas att dessa genomförs pÄ ett genomtÀnkt och kvalitetssÀkrat sÀtt
Genetisk och etologisk analys av vallningsbeteende hos border collie
The ability of a dog to perform some kind of practical work, for example hunting or herding, depends among other things on its behavioural characteristics. In animal breeding it is not always easy though to select for behavioural traits. It may, for example, be difficult to identify traits that are not only heritable but also of importance for the dogs' ability to perform the practical work of interest. Moreover, it is often difficult to accomplish accurate measurements of behavioural traits. When selecting dogs for breeding, it is usually preferable to evaluate them using an objective and standardized bahavioural test, rather than results from field trials. The Swedish Herding Dogs Club (Svenska Vallhundsklubben, SVaK) use a standardized method, here named AHC, to assess the herding characteristics of dogs, especially border collies. The dogs' typical behaviour, mainly towards sheep, is described using predefined scales. The AHC has existed in two versions, and since the start in 1989 almost 2700 border collies have participated.
In this study close to 2700 AHC-results, together with pedigree information, have been used to estimate breeding values for the participating dogs and heritabilities for the traits assessed in the AHC. Using factor analysis the herding traits of the AHC have been combined to broader traits. Breeding values, heritabilities and genetic correlations were estimated for the broader traits.
Heritabilities for the 17 traits of the earlier version of the AHC were estimated to between 0.14 and 0.50. All traits but two showed medium to high heritabilities. Standard errors varied between 0.043 and 0.060. Heritabilities of the 19 traits of the later version of the AHC varied between 0.03 and 0.41 with standard errors 0.041-0.074. All traits but one showed low to medium heritabilities. There are several possible explanations for the lower heritabilities in the later version. For example the scales, i.e. the way the traits are measured, might have a less appropriate construction. Also, the traits seem to be less well defined, maybe resulting in confusion among judges.
In the earlier version of the AHC there were 12 traits describing the dogs' behaviour towards the herd. The factor analyses suggest that these can be explained by four overall traits, which I have chosen to call Authority/Concentration, Distance to herd, Speed and Tendency to bite. The heritabilities for each overall trait are higher than for any of that trait's component traits (with the exception of Tendency to bite, which corresponds to a single original trait). The higher heritabilities are probably due to rather high genetic correlations between the component (original) traits. A secondary factor analysis revealed that nine of the twelve traits could be explained by one broad trait, which I have called Herding characteristic. The heritability for Herding characteristic was estimated to 0.55 with standard error 0.055.
To try to explain the outcome of the factor analyses, I have discussed two different models. According to the first model, equivalences to the overall herding traits can be found in the wolf's hunting sequence. The second model explains the overall traits as being expressions for the personality traits Extraversion and Neuroticism. The first model does not exclude the second or vice versa. But even though there is no question that a herding border collie uses hunting behaviours, it is also reasonable to assume that the purpose of these behaviours differs between the hunting wolf and the herding border collie. Therefore I find it easier to understand herding behaviour by applying a personality perspective.
When compared to other studies where estimates of heritability of different hunting or herding traits in dogs have been made, the results in the present study show very high heritabilities, especially for the earlier version of the AHC. For several of the traits it is even possible to select animals for breeding using only the phenotypic records. The overall traits are all possible to select for in this way. In other words, there are several possibilities to accomplish effective selection for most of the traits in the earlier version of the AHC.En hunds förmÄga att utföra nÄgot slag av praktiskt arbete, till exempel grytjakt, vallning
eller bruksarbete, Àr bland annat beroende av dess beteendeegenskaper. Det Àr emellertid
inte alldeles enkelt att bedriva systematisk avel för beteendeegenskaper. Problemen
bestÄr bland annat i att lyckas identifiera egenskaper som dels Àr av betydelse för den
praktiska arbetsprestationen, dels Àr Àrftliga. Vidare Àr det mÄnga gÄnger svÄrt att mÀta de
egenskaper man Àr intresserad av pÄ ett tillförlitligt sÀtt. DÄ hundar skall avelsvÀrderas Àr
en objektiv och standardiserad egenskapsbeskrivning oftast att föredra framför
traditionella tÀvlingar. Svenska Vallhundsklubben (SVaK) har utarbetat en metod för att
beskriva en hunds vallningsegenskaper som kallas arbetsbeskrivning. En
arbetsbeskrivning genomförs genom att hunden iakttas i samband med vallhundstrÀning,
varvid en bedömning görs av pÄ vilket sÀtt egenskaperna kommer till uttryck.
Bedömingen görs utifrÄn en standardiserad skala med olika beteendealternativ.
Arbetsbeskrivningen har funnits i tvÄ versioner och sedan starten 1989 har sammanlagt
nÀrmare 2700 hundar, nÀstan alla border collier, blivit beskrivna.
I denna studie har resultaten frÄn de arbetsbeskrivningar som genomförts av border
collier, tillsammans med slÀktskapsinformation, anvÀnts för att skatta avelsvÀrden för de
deltagande hundarna och arvbarheter för de ingÄende egenskaperna.
Vallningsegenskaperna i arbetsbeskrivningen har kombinerats till övergripande
egenskaper med hjÀlp av faktorsanalys, dels med avelsvÀrdena som utgÄngspunkt, dels
med fenotypvÀrdena. För de övergripande egenskaperna har avelsvÀrden, arvbarheter och
genetiska korrelationer skattats.
Arvbarheterna för de 17 egenskaperna i den tidigare av de tvÄ versionerna av
arbetsbeskrivningen kunde skattas till mellan 0,14 och 0,50 och alla utom tvÄ visar
medelhöga eller höga arvbarheter. Medelfelen varierar mellan 0,043 och 0,060. För den
senare beskrivningen Àr arvbarheterna mellan 0,03 och 0,41 med medelfel 0,041-0,074.
Alla egenskaper utom en visar lÄg eller medelhög arvbarhet. Det finns flera möjliga
orsaker till de lÀgre arvbarheterna i den senare versionen, till exempel att
bedömningsskalorna, det vill sÀga sÀttet att mÀta egenskaperna, har en för de statistiska
analyserna mindre lÀmplig konstruktion. Egenskaperna förefaller ocksÄ vara nÄgot mer
svÄrdefinierade, och dÀrför kan det vara sÄ att beskrivarna inte alltid bedömt samma
saker.
Faktorsanalyserna tyder pÄ att de tolv egenskaper i den tidigare beskrivningen som
beskriver hundens agerande mot djuren i en vallningssituation, kan sammanfattas i fyra
övergripande egenskaper. UtifrÄn vad jag uppfattar att dessa övergripande egenskaper
beskriver, har jag valt att kalla dem för Pondus/Koncentration, DjuravstÄnd, Tempo och
BitbenÀgenhet. Med undantag för BitbenÀgenhet, som bestÄr av endast en av de
ursprungliga egenskaperna, har samtliga övergripande egenskaper högre arvbarheter
(0,31-0,55) Àn nÄgon av de ursprungliga egenskaper som ingÄr i respektive övergripande
egenskap. De högre arvbarheterna beror sannolikt pÄ att de ursprungliga egenskaper som
bygger upp respektive övergripande egenskap Àr genetiskt korrelerade till varandra. Med
utgÄngspunkt frÄn de fyra faktorerna som föll ut i den primÀra faktorsanalysen kunde, i en sekundÀr analys, konstateras att nio av de tolv vallningsegenskaperna kan
sammanfattas i en bred övergripande egenskap som jag kallat VallningskaraktÀr.
Arvbarheten för VallningskaraktÀr skattades till 0,55 med medelfelet 0,055.
Jag har diskuterat tvÄ alternativa modeller som förklaring till varför
vallningsegenskaperna grupperar sig som de gör i faktorsanalyserna. Enligt den ena
modellen kan de övergripande vallningsegenskaperna hÀnföras till olika delbeteenden i
vargens jaktbeteende. Enligt den andra modellen Àr de övergripande
vallningsegenskaperna uttryck för de breda personlighetsegenskaperna Extraversion och
Neuroticism. Den ena modellen utesluter inte pÄ nÄgot sÀtt den andra, utan de kan ses
som tvÄ olika sÀtt att pÄ olika nivÄer förklara samma sak. Men Àven om den vallande
border collien anvÀnder vargjaktbeteenden har den inte samma syfte med dessa som en
jagande varg har. DÀrför finner jag det lÀttare att förstÄ vallningsbeteendet utifrÄn ett
personlighetsperspektiv Àn ur ett vargjaktperspektiv.
JÀmfört med andra liknande arvbarhetsskattningar visar egenskaperna i SVaK:s
arbetsbeskrivningar, i synnerhet den tidigare versionen, mycket höga arvbarheter. För
mÄnga av egenskaperna Àr det till och med möjligt att avelsvÀrdera hundarna utifrÄn
deras egna resultat, sÄ kallad individprövning. Detta gÀller i Àn högre grad de
övergripande egenskaperna. Det finns med andra ord mycket goda förutsÀttningar för att
bedriva effektiv selektion för avel för flertalet egenskaper i den första versionen av
arbetsbeskrivningen
Von gesellschaftlichen GesprĂ€chen ĂŒber politische GegenstĂ€nde : eine Einladungs-Schrift zur Feier des hohen Geburts-Festes Ihro KĂ€iserlichen MajestĂ€t Catharina Alexiewna Selbstherscherinn von ganz Russland : Reval am 20sten April 1793
http://tartu.ester.ee/record=b1655911~S1*es
Genome-wide association studies for canine hip dysplasia in single and multiple populations â implications and potential novel risk loci
Background Association mapping studies of quantitative trait loci (QTL) for canine hip dysplasia (CHD) can contribute to the understanding of the genetic background of this common and debilitating disease and might contribute to its genetic improvement. The power of association studies for CHD is limited by relatively small sample numbers for CHD records within countries, suggesting potential benefits of joining data across countries. However, this is complicated due to the use of different scoring systems across countries. In this study, we incorporated routinely assessed CHD records and genotype data of German Shepherd dogs from two countries (UK and Sweden) to perform genome-wide association studies (GWAS) within populations using different variations of CHD phenotypes. As phenotypes, dogs were either classified into cases and controls based on the Federation Cynologique Internationale (FCI) five-level grading of the worst hip or the FCI grade was treated as an ordinal trait. In a subsequent meta-analysis, we added publicly available data from a Finnish population and performed the GWAS across all populations. Genetic associations for the CHD phenotypes were evaluated in a linear mixed model using 62,089 SNPs. Results Multiple SNPs with genome-wide significant and suggestive associations were detected in single-population GWAS and the meta-analysis. Few of these SNPs overlapped between populations or between single-population GWAS and the meta-analysis, suggesting that many CHD-related QTL are population-specific. More significant or suggestive SNPs were identified when FCI grades were used as phenotypes in comparison to the case-control approach. MED13 (Chr 9) and PLEKHA7 (Chr 21) emerged as novel positional candidate genes associated with hip dysplasia. Conclusions Our findings confirm the complex genetic nature of hip dysplasia in dogs, with multiple loci associated with the trait, most of which are population-specific. Routinely assessed CHD information collected across countries provide an opportunity to increase sample sizes and statistical power for association studies. While the lack of standardisation of CHD assessment schemes across countries poses a challenge, we showed that conversion of traits can be utilised to overcome this obstacle
Unravelling selection signatures in a single dog breed suggests recent selection for morphological and behavioural traits
Strong selection has resulted in substantial morphological and behavioral diversity across modern dog breeds, which makes dogs interesting model animals to study the underlying genetic architecture of these traits. However, results from between-breed analyses may confound selection signatures for behavior and morphological features that were coselected during breed development. In this study, we assess population genetic differences in a unique resource of dogs of the same breed but with systematic behavioral selection in only one population. We exploit these different breeding backgrounds to identify signatures of recent selection. Selection signatures within populations were found on chromosomes 4 and 19, with the strongest signals in behavior-related genes. Regions showing strong signals of divergent selection were located on chromosomes 1, 24, and 32, and include candidate genes for both physical features and behavior. Some of the selection signatures appear to be driven by loci associated with coat color (Chr 24; ASIP) and length (Chr 32; FGF5), while others showed evidence of association with behavior. Our findings suggest that signatures of selection within dog breeds have been driven by selection for morphology and behavior. Furthermore, we demonstrate that combining selection scans with association analyses is effective for dissecting the traits under selection
Centrifugal acceleration in the magnetotail lobes
Combined Cluster EFW and EDI measurements have shown that cold ion outflow in the magnetospheric lobes dominates the hydrogen ion outflow from the Earth's atmosphere. The ions have too low kinetic energy to be measurable with particle instruments, at least for the typical spacecraft potential of a sunlit spacecraft in the tenuous lobe plasmas outside a few <I>R</I><sub>E</sub>. The measurement technique yields both density and bulk velocity, which can be combined with magnetic field measurements to estimate the centrifugal acceleration experienced by these particles. We present a quantitative estimate of the centrifugal acceleration, and the velocity change with distance which we would expect due to centrifugal acceleration. It is found that the centrifugal acceleration is on average outward with an average value of about of 5 m s<sup>&minus;2</sup>. This is small, but acting during long transport times and over long distances the cumulative effect is significant, while still consistent with the relatively low velocities estimated using the combination of EFW and EDI data. The centrifugal acceleration should accelerate any oxygen ions in the lobes to energies observable by particle spectrometers. The data set also put constraints on the effectiveness of any other acceleration mechanisms acting in the lobes, where the total velocity increase between 5 and 19 <I>R</I><sub>E</sub> geocentric distance is less than 5 km s<sup>&minus;1</sup>
Observation of MeV-Gamma-Rays from relativistic electron precipitation with Balloon Borne Experiment around the Northern Polar Cap
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