24,608 research outputs found
Genetic diversity and relationships among Nguni cattle populations in three Southern African countries
No full textMSCAGR (Animal Science)Department of Animal ScienceThe Nguni is a transboundary indigenous Southern African cattle breed. The breed has distinct populations that are adapted to the different ecological zones of Southern Africa. Previous work on characterising the Nguni has been limited to within-country studies. Thus, the aim of the current study was to genetically characterise South African (SA) Nguni, Mozambican Nguni (Landim) and Swazi Nguni populations across Southern African region using a panel of 25 microsatellite markers, recommended by FAO and ISAG for genetic diversity studies. Genotypic data were generated from 90 unrelated autosomal DNA samples of the three cattle populations (SA Nguni n=30, Mozambican Nguni (Landim) n=30 and Swazi Nguni n=30) collected from government research stations and stud herds. Five South African beef cattle breeds’ DNA profiles were obtained from the ARC-DNA database and used as reference populations. A majority of the microsatellite markers were highly polymorphic across the studied populations. High genetic diversity was detected and expected heterozygosity varied from 71% (Landim) to 75% (SA Nguni) with a higher mean number of alleles (MNA) in the SA Nguni (7.52±0.42) compared to the Swazi Nguni (6.92±0.40) and Landim (7.16±0.43) populations. Observed heterozygosity (Ho) (0.597±0.046) compared to expected heterozygosity (He) (0.719±0.022) was lowest for the Swazi Nguni, confirming a relatively high level of inbreeding (FIS=0.158) in that population. An analysis of molecular variance (AMOVA) revealed that 9.61% of the total variation occurred among populations, while 90.39% occurred within populations. Short genetic distance (29.9%) was observed between Landim and Swazi Nguni, with the SA Nguni (>50%) being the most genetically distant population. The distant relationship between SA Nguni and the other two Nguni cattle populations was further confirmed by neighbor-joining (NJ) tree, Principal Coordinates Analyses (PCoA) and Factorial Corresponding Analysis (FCA). The structure of the three Nguni cattle populations clustered independently, despite some evidence of admixture. Additionally, genetic differentiation and population structure within four Mozambican indigenous cattle populations were investigated using the same panel of microsatellite markers. The analysis of unrelated autosomal DNA was performed on 120 animals (Angone n=30, Bovine de Tete n=30, Landim n=30 and Namaacha Nguni n=30), which presented sufficient genetic diversity across all populations. Estimates of mean number of alleles, observed and expected heterozygosities were 6.920±0.20, 0.68±0.02 and 0.71±0.01, respectively. Genetic differentiation among the populations accounted for 8.02% of total genetic variability. Negative (-0.025±0.029) to low positive (0.073±0.050) levels of inbreeding were observed within the four populations. The genetic distance, NJ tree, PCoA and FCA revealed a
close relationship between Bovine de Tete and Landim as opposed to Angone and Namaacha Nguni. STRUCTURE analysis assigned the four Mozambican populations independently; however Bovine de Tete and Landim showed relatively higher levels of admixture with each other than Angone and Namaacha Nguni. It can be concluded that SA Nguni, Landim and Swazi Nguni populations accomplish high genetic diversity and they are genetically distant; however, the two latter populations are closely related. These results present useful informationNR
Genetic analysis of calving difficulty in South African Holstein cattle
No full textNo keywordsCalving difficulty is an economically important welfare-related trait in dairy cattle and,
therefore, should be included in breeding objectives of South African Holstein dairy cattle.
In South Africa, however, calving performance traits are not included in the national
genetic evaluation programme. The present study was therefore carried out to estimate
environmental and genetic influences on maternal calving difficulty in South African
Holstein cattle, to develop models for genetic prediction of the trait. The final data set
comprised of 14 250 calving records of 8 832 cows, from 14 herds, participating in the
National Dairy Animal Recording and Improvement Scheme during the period 2009 to
2018. General Linear Models (GLM) technique was used to investigate environmental
influences (SAS 2016) version 9.4. Sex of calf, parity, herd-year-season, and age of dam
at calving had significant effects (P <0.05) on maternal calving difficulty. Variance
components and for computing genetic parameters were estimated by the Restricted
Maximum Likelihood (REML) approach using ASReml program., for variance component
estimation, were included in the model. Estimates of maternal heritability effects from the
linear animal model were 0.10±0.04, 0.04±0.09 and 0.12±0.10 for parities 1, 2 and 3,
respectively. The estimate across all heritability were 0.04±0.04, with a repeatability
model of 0.04±0.04 respectively. These estimates indicate low accuracy of selection for
calving difficulty in the South African Holstein cattle population. However, these results provide the basis for computing estimated breeding values (EBVs), which will enable the
reduction of calving difficulty in the South African Holstein cattle population; thus, genetic
gain and performance improvement were slow.M. Sc. (Life Sciences)Life and Consumer Science
On Some Optimization Problems that Can Be Solved in O(n) Time
No full textWe consider nine elementary problems in optimization. We simply explore the conditions for optimality as known from the duality theory for convex optimization. This yields a quite straightforward solution method for each of these problems. The main contribution of this paper is that we show that even in the harder cases the solution needs only O(n) time.Accepted author manuscriptDiscrete Mathematics and Optimizatio
The farm gate carbon and water footprint of diverse beef cattle genotypes in South Africa and its environmental impact
No full textAbstracts in English and TsongaThe aim of this study is to estimate the current farm-gate carbon and blue water footprint of the major beef breeds in South Africa that is representative of the different breed types e.g. Sanga (indigenous), Sanga derived, Zebu, Zebu derived, British and European breeds. A simulation programme was used to simulate the methane production (expressed as methane intensity) and blue water footprint of a weaner calf production system for 9 diverse beef cattle genotypes. The chosen genotypes were based on the number of animals and the availability of data. The breeds involved were: Afrikaner, Nguni, Bonsmara, Angus, Hereford, Brahman, Brangus, Charolais and Simmentaler. The simulation study also involved a farm size of 1200 hectares (ha), with a carrying capacity of 6 hectares per Large Stock Unit (LSU) which could carry 200 LSU’s. Frame size specific equations were used to estimate cow LSU units. The Tier 2 Intergovernmental Panel on Climate Change (IPCC) approach for the methane (CH4) emission values, as already published in the literature was used. Through this approach it was estimated that the enteric methane emissions factor (MEFenteric) of a LSU was equivalent/equal to 94kg methane/year. Furthermore, a 15% replacement rate, 2% pre-weaning mortality, 2% post weaning mortality and a 4% use of breeding bulls were assumed. The blue water use intensity can be estimated in the same way, and it was assumed that for every kg of dry matter intake, a ruminant animal needs 4 litres (L) of water, but it can be increased by 50 % when it is hot. Therefore, an average of 5 litres water intake was used. A LSU needs 9kg dry matter per day and therefore 45 litres of water per day. It was thus estimated that the litres of blue water consumed on the farm was 16 425 litres/year/LSU multiplied by 200 LSU’s which was equal to 3 285 kilolitres. Actual published production values (weaning weight, cow weight, fertility) for each breed was used. For the small frame Afrikaner and Nguni breeds, it was estimated that the methane intensity (kg methane per kg live weight leaving the farm) was 0.60kg and 0.68 kg, respectively. For the medium frame Bonsmara, Angus, Hereford, Brahman and Brangus, the methane intensity was 0.59kg, 0.59kg, 0.64kg, 0.61kg and 0.62kg, respectively. Lastly, for the large frame Charolais and Simmentaler, the methane intensity was 0.85kg and 0.73kg, respectively. The methane intensity varied from 0.59kg CH4 to 0.85kg CH4, which represents a 44% difference. However, when comparing different size breeds, assuming a 10% improvement in each trait, the methane intensity varied from 0.55kg to 0.75kg,
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respectively and a 55% difference was then observed. Moreover, when estimating the water use intensity, it varied from 103 to 148 kilolitres from small to large frame breeds and when a 10% improvement was applied it then ranged from 96 to 131 kilolitres per kg live weight leaving the farm. It was surprising that the Nguni had a medium methane and water intensity, since it is the most fertile breed. However, it should be taken into account that the Nguni was the smallest breed and 147 cows with calves could be kept on the 1 200ha farm. These cows and calves produce large quantities of methane and utilizes large/high water quantities as compared to some of the other breeds. The Afrikaner, Bonsmara, Angus, Brahman and Brangus breeds have low methane and water use intensities and can be regarded as environmentally friendly. The Nguni and Hereford breeds have medium methane and water use intensities while the Charolais and Simmentaler breeds have higher methane and water use intensities. This information can be used to develop a model that can estimate the farm-gate methane emission and water use intensity for different breed types, production levels and systems. Such a model will be valuable in the event that carbon taxes are introduced and total life cycle of water use can be fully analysed.Xikongomelo xa phurojeke leyi i ku pima khaboni ya sweswi ya farm-gate na mati ya blue water footprint ya tinxaka letikulu ta nyama ya homu e Afrika Dzonga leswi yimelaka tinxaka to hambana ta tinxaka xikombiso Sanga (indigenous), Sanga derived, Zebu, Zebu derived, British na Tinxaka ta le Yuropa. Dyondzo yitirhisiwile ku tekelela vuhumelerisi bya methane (leswi kombisiwaka tani hi matimba ya methane) na blue water footprint ya weaner calf production system eka 9 wa ti genotypes to hambana hambana ta tihomu ta homu. Ti genotypes leti hlawuriweke ati seketeriwile eka nhlayo ya swifuwo xikan’we naku kumeka ka data. Tinxaka leti katsekaka akuri: Afrikaner, Nguni, Bonsmara, Angus, Hereford, Brahman, Brangus, Charolais na Simmentaler. Dyondzo ya simulation yitlhele yi katsa vukulu bya purasi ra 1200 wa ti hectares (ha), laha kungana vuswikoti byo rhwala bya 6 wa ti hectares hi Large Stock Unit (LSU) leyinga rhwala 200 wa ti LSU’s. Kutani ku tirhisiwile ti equations to hlawuleka ta vukulu bya furemu ku ringanyeta tiyuniti ta LSU ta tihomu. Endlelo ra Tier 2 ra Phanele ya le Xikarhi ka Mfumo eka ku Cinca ka Maxelo (IPCC) eka mimpimo ya ku humesiwa ka methane (CH4), tanihilaha se swi kandziyisiweke hakona eka matsalwa. Hiku tirhisa endlelo leri ku ringanyetiwe leswaku enteric methane emissions factor (MEFenteric) ya LSU ayi ringana/ringana na 94kg methane/lembe. Kuya emahlweni, 15% wa nhlayo ya ku cinciwa, 2% wa ku fa ka le mahlweni ka ku lumuriwa, 2% wa ku fa endzhaku ka ku lumuriwa na 4% wa ku tirhisiwa ka tinkunzi leti fuyiwaka swi tekiwile. Kutala ka matirhiselo ya mati ya wasi yanga ringanyetiwa hindlela leyi fanaka, naswona aku ehleketiwile leswaku eka kg yin’wana na yin’wana ya swakudya swo oma leswi dyiwaka xifuwo lexi dyaka swilava 4 wa tilitara (L) ta mati, kambe xinga engeteriwa hi 50 % loko xi hisa. Hikokwalaho, ku tirhisiwile xiringaniso xa 5 wa tilitara ta mati lawa ya dyiwaka. LSU yilava 9kg ya swakudya swo oma hi siku naswona hikokwalaho ka sweswo 45 wa tilitara ta mati hi siku. Xisweswo swiringanyetiwile leswaku tilitara ta mati ya wasi lawa ya tirhisiwaka e purasini akuri 16 425 wa tilitara/lembe/LSU ku andzisiwa hi 200 wa ti LSU leswi ringanaka na 3 285 wa tikhilolitara. Mimpimo ya xiviri ya vuhumelerisi leyi kandziyisiweke (ndzilo wa ku lumuriwa, ntiko wa tihomu, ku veleka) eka muxaka wun’wana na wun’wana wutirhisiwile. Eka tinxaka letintsongo ta frame, Afrikaner na Nguni, aku ringanyetiwa leswaku matimba ya methane (kg methane hi kg ya ntiko lowu hanyaka lowu humaka
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e purasini) akuri 0.60kg na 0.68 kg, hiku landzelelana. Eka furemu yale xikarhi, ya Bonsmara, Angus, Hereford, Brahman, Brangus, matimba ya methane akuri 0.59kg, 0.59kg, 0.64kg, 0.61kg, 0.62kg, hiku landzelelana. Naswona eka furemu leyikulu, Charolais na Simmentaler, matimba ya methane akuri 0.85kg na 0.73kg, hiku landzelelana. Nhlayo ya methane ayi hambana kusuka eka 0.59kg CH4 kuya eka 0.85kg CH4, leswi yimelaka ku hambana ka 44%. Hambiswiritano, loko ku pimanyisiwa tinxaka tohambana hambana ta vukulu, hiku tekela enhlokweni ku cinca ka 10% eka mfanelo yin’wana na yin’wana, matimba ya methane ya hambana kusuka eka 0.55kg kuya eka 0.75kg, hiku landzelelana. Naswona kwalomu ka 55% wa ku hambana ku tlhele ku voniwa. Ku tlula kwalaho, loko ku ringanyetiwa matimba ya matirhiselo ya mati, ya hambana kusuka eka 103 kuya eka 148 kilolitres kusuka eka tinxaka letintsongo kuya eka letikulu ta furemu naswona loko 10% wa ku cinca ku cheriwa kutani akuri kusuka eka 96 kuya eka 131 kilolitres hi ntiko lowu hanyaka lowu humaka e purasini. A swi hlamarisa kuva va Nguni ayiri na methane yale xikarhi xikan’we na mati yotala, tani hileswi kunga muxaka lowu noneke swinene. Hambiswiritano, swifanele ku tekeriwa enhlokweni leswaku Nguni akuri muxaka lowuntsongo swinene naswona 147 wa tihomu letingana marhole tinga hlayisiwa eka purasi ra 1 200ha. Tihomu leti na marhole ya humesa nhlayo leyikulu ya methane naswona ya tirhisa mati lamakulu/yale henhla loko ku pimanyisiwa na tinxaka ta Afrikaner, Bonsmara, Angus, Brahman na Brangus. Tinxaka ta Afrikaner, Bonsmara, Angus, Brahman na Brangus tina methane yale hansi na matirhiselo ya mati naswona tinga tekiwa tani hi letinga onhi mbango. Tinxaka ta Nguni na Hereford tina methane yale xikarhi xikan’we na matirhiselo ya mati kasi tinxaka ta Charolais na Simmentaler tina methane yale henhla xikan’we na matirhiselo ya mati. Mahungu lawa yanga tirhisiwa ku tumbuluxa modele lowu nga ringanyetaka ku humesiwa ka methane ya le purasini xikan’we na matimba ya matirhiselo ya mati eka tinxaka tohambana hambana ta tinxaka, swiyimo swa vuhumelerisi na tisisiteme. Modele wo tano wu ta va wa nkoka loko ko tshuka ku nghenisiwa swibalo swa khaboni naswona xirhendzevutani xa vutomi hinkwabyo xa matirhiselo ya mati xi ta xopaxopiwa hi ku hetiseka.M. Sc. (Agriculture)College of Agriculture and Environmental Science
An O(n log n) algorithm for finding dissimilar strings
No full textLet be a finite alphabet and . A string is said to be -dissimilar to , if no length substring of is equal to any length substring of . We present an algorithm which on input and an integer outputs an integer and such that:
- is -dissimilar to .
- There does not exist a string of length which is dissimilar to .Technical report LCSR-TR-26
Tricritical O(n) models in two dimensions
No full textWe show that the exactly solved low-temperature branch of the two-dimensional O(n) model is equivalent to an O(n) model with vacancies and a different value of n. We present analytic results for several universal parameters of the latter model, which is identified as a tricritical point. These results apply to the range n ?3/2 and include the exact tricritical point, the conformal anomaly, and a number of scaling dimensions, among which are the thermal and magnetic exponents, and the exponent associated with the crossover to ordinary critical behavior and to tricritical behavior with cubic symmetry. We describe the translation of the tricritical model in a Coulomb gas. The results are verified numerically by means of transfer-matrix calculations. We use a generalized ADE model as an intermediary and present the expression of the one-point distribution function in that language. The analytic calculations are done both for the square and the honeycomb lattice.Kavli Institute of NanoscienceApplied Science
O. N. Malmquist
No full textO. N. Malmquist was a political editor for the Salt Lake Tribune, and author of "First One Hundred Years; A History of the Salt Lake Tribune 1871-1971.
FUNDAMENTAL AND TORSIONAL COMBINATION BANDS OF NO-CH AND NO-CD IN THE NO REGION
No full textAuthor Institution: Department of Physics and Astronomy, University of Calgary; Calgary, AB T2N 1N4, CANADA; Steacie Institute for Molecular Sciences, National Research; Council of Canada, Ottawa, ON K1A 0R6, CANADASpectra of the weakly-bound NO-CH and NO-CD complexes in the region of the NO fundamental band (~2224 cm) are observed in a pulsed supersonic slit jet expansion probed with a tunable diode laser. Two bands are analyzed for each complex: the fundamental (N-N stretch), and a combination involving the intermolecular torsional (out-of-plane bend) vibration. The resulting torsional frequencies are 44.37 and 40.01 cm for the CH and CD complexes, respectively. This represents the first observation of the NO-CD isotopomer, and the first direct determination of an intermolecular frequency for nitrous oxide - acetylene
Multicritical points of the O(N) scalar theory in 2 < d < 4 for large N
No full textWe solve analytically the renormalization-group equation for the potential of the O(N)-symmetric scalar theory in the large-N limit and in dimensions 2<d<4, in order to look for nonperturbative fixed points that were found numerically in a recent study. We find new real solutions with singularities in the higher derivatives of the potential at its minimum, and complex solutions with branch cuts along the negative real axis. © 2018 The Author
Self-archiving practice and the influence of publisher policies in the social sciences
No full textAuthors in different disciplines exhibit very different behaviours on the so-called ‘green’ road to open access, i.e. self-archiving. This study looks at the self-archiving behaviour of authors publishing in leading journals in six social science disciplines. It tests the hypothesis that authors are self-archiving according to the norms of their respective disciplines rather than following self-archiving policies of publishers, and that, as a result, they are self-archiving significant numbers of publisher PDF versions. It finds significant levels of
self-archiving, as well as significant self-archiving of
the publisher PDF version, in all the disciplines
investigated. Publishers’ self-archiving policies have
no influence on author self-archiving practice
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