1,538 research outputs found
Breeding against osteochondrosis : phenotypic and genetic analyses in horses and pigs
No full text Osteochondrosis (OC) is a disturbance in the process of endochondral ossification during skeletal growth. The objectives of this thesis were to assess the prevalence and genetic parameters of OC, and to facilitate optimization of breeding against OC in horses and pigs. In the Dutch warm blood horse, 70% of individuals showed joint abnormalities in at least one of the 28 locations examined. Joint abnormalities were divided into flattened bone contours and bone fragments. Genetic parameters were estimated for flattened bone contours, fragments and overall OC. Heritability was 0.08 for flattened bone contours, 0.22 for fragments, and 0.23 for overall OC. In fattening pigs, the prevalence of OC was 41%, and 12% of the individuals had severe OC. The prevalence was highest for individuals kept on a concrete, partially slatted floor with ad libitum feeding (58%), and lowest for individuals kept on a deep litter floor with restricted feeding (34%). These results demonstrate that the prevalence of OC can be reduced by applying deep litter floors and restricted feeding. The differences in growth patterns between pigs with and without OC were investigated also. After 28 days of age, piglets with severe OC at slaughter started to grow faster, and were significantly heavier after 70 days of age than pigs without OC at slaughter. These results suggest that OC might be related to high growth rates during a specific time period. To evaluate prospects for breeding against OC, selection responses were compared between breeding schemes using phenotypic selection based on own performance or progeny testing and genomic selection. The results show that, when genomic information has an equal accuracy as phenotypic information before selection, it will have a lower equilibrium response to selection because it has a larger Bulmer effect. Especially for low heritable traits, genomic selection was of additional value over traditional selection. The general discussion argues that OC has both economical and practical relevance for the current horse industry. Simulations showed potential for genomic selection compared to the current breeding program in the Dutch warmblood horse (KWPN), even with small reference populations. In pigs, OC is a more serious problem in sows than in fattening pigs, because sows live longer. A decrease in OC prevalence will, therefore, yield larger economic and welfare benefits then apparent from results on fattening pigs. Also for pigs, simulations indicated possibilities for genomic selection. The final section of the general discussion proposes directions for future research.</p
THE MICROWAVE SPECTRA OF THE LINEAR OC HCCCN, OC DCCCN, AND THE T-SHAPED HCCCN CO COMPLEXES
No full textAuthor Institution: Department of Natural Sciences, Union College, Barbourville, KY 40906; Department of Chemistry, Wesleyan University, Middletown, CT 06459The rotational spectra of OC HCCCN, OC DCCCN, and HCCCN CO have been recorded using pulsed-jet Fourier transform microwave spectroscopy. Accurate molecular constants have been obtained and agree with the results from IR spectroscopy.} \textbf{204}, 145-151 (1993)} } \textbf{180}, 1-6 (1996)} The OC HCCCN is hydrogen-bonded in a linear configuration, and the HCCCN CO is T-shaped with the CO molecule at the nitrogen end of the cyanoacetylene. The C, the N, and the O isotopologues for both the OC HCCCN and OC DCCCN complexes have been observed in natural abundance. The fully substituted molecular structure of the OC HCCCN complex has been determined. The results will be compared with those of the corresponding complexes of HCN
Sensitivity Analysis and Validation of Advanced Soil Model for OC Clays
No full textThis research has shed light on the capability of the HASP model in reproducing the dilatant behaviour of OC clays in drained and undrained conditions. The model is formulated by employing a combined hardening rule and uses the void ratio as a state variable while maintaining the simplicity of the MCC model. However, a sensitivity analysis has revealed that the model is sensitive to some input parameters which when varied slightly can largely affect the outcome of an analysis.This has led to the formulation of the PLAXIS OC clay model while maintaining the framework of the HASP model but replacing the void ratio with volumetric strain as the state variable. Thus resulting in the use of the modified compression (λ*) and swelling (κ*) indexes which are used in obtaining the soil stiffness parameters used as model inputs. The PLAXIS OC clay model features the use of real soil stiffness parameters instead of soil indexes, the addition of small stain stiffness by T. Benz to improve model prediction in the small strain region and the elimination of the sensitivity issues noticed when using the HASP model.The PLAXIS OC clay model is validated for boom clay (BC) at single stress points by simulating CU test and comparing with the available experimental data for the BC. Good agreement is found with experimental data as shown in the stress strain, pore water pressure and stress path plots obtained from the analysis.Furthermore, the model is used to simulate boom clay in a trial excavation. Piezometers and extensometers are installed into the BC layer prior to the excavation to monitor the changes in porewater pressure and vertical displacement (heave) on the BC during the excavation. A comparison of the numerical and experimental data shows that good agreement is observed in porewater pressures and vertical displacement in the BC layer
INFRARED SPECTROSCOPY AUTO MOLECULAR DYNAMICS IN OC-HI
No full textAuthor Institution: Department of Chemistry, Texas A\&M UniversityThe rovibrational analysts of the , HI stretching vibration in OC-HI has been completed giving the following molecular constants: MHz and kHz. Hot bands and combination, bands associated with both the previously assigned , OC stretching vibration and the vibration have also been analysed. These results will also be presented and interpeted in terms of the molecular and associated tunneling dynamics of this complex
FREE JET ABSORPTION SPECTRA OF THE VAN DER WAALS COMPLEX
No full textAuthor Institution: Department of Chemistry, University of Southern CaliforniaThe van der Waals complex was observed in a 5''-pulsed-slit free jet expansion. The complex was detected by the IR absorption in the vicinity of 1-0 vibrational transition of C-O. Four isotopic progressions were recorded in the spectra. The rotational structure was consistent with a linear . The spectra were well-fitted by semirigid-rotor linear molecule model, the rotational constants for and isotopomers were obtained. The band origins of were found to be 2152.83836(17), 2152.83929(16), 2152.84117(15) and for the isotopomers of and , respectively. From the isotope substituted rotational constants, the distances of the centers-of-mass of CO and were calculated to be 4.864 {\AA} and 4.875 {\AA} for the excited and ground state, respectively. The van der Waals bond formation siginficantly perturbed both the CO and bond lengths. In the ground state, the bond of the complex was 0.027 {\AA} shorter than that of the uncomplexed CO, while the Br-Br distance of the complex was 0.037 {\AA} longer than the bond length of free
ISOTOPE EFFECTS IN THE HIGH RESOLUTION INFRARED SPECTRA OF OC-HF
No full text E.K. Kyro, P. Shoja-Chaghervand, K. McMillan, M. Eliades, D. Danzeiser, and J.W. Bevan, J. Chem. Phys. 79, 78 (1983). K.W. Jucks and R.E. Miller, J. Chem. Phys. (to be published).Author Institution: Molecular Spectroscopy Division, National Bureau of StandardsInfrared spectra of OC-HF, , and have been observed in the vicinity of the HF stretching fundamental using a difference frequency laser spectrometer and a long pathlength thermal equilibrium White cell. The results on the OC-HF isotopic form extend previous White cell and molecular beam measurements by Kyro and Jucks . The band origins for the complexes: for OC-HF, for , and for , are all red shifted from the fundamental of uncomplexed HF and do not exhibit a systematic trend with CO stretching or bending frequency. The observed positive are consistent with the increased van der Waals binding in the excited state. The homogeneous linewidths for the transitions are large (HWHM * 180 MHz with roughly equal contributions from pressure broadening and vibrational predissociation) and essentially isotope independent. Local perturbations are observed for OC-HF and , but not for
A STUDY OF THE INTERMOLECULAR VIBRATION IN OC- BASED ON NEAR INFRARED SPECTROSCOPY
No full textAuthor Institution: Department of Chemistry, Texas A\&M University; Steacie Institute, National Research CouncilThe near infrared combination bands of and have been recorded using a high frequency wavelength modulation diode laser supersonic jet spectrometer. In addition, the static gas phase spectra of the associated and hot bands in have been recorded using Fourier transform infrared absorption spectroscopy. The combined results permit evaluation of rovibrational constants for the low frequency intermolecular bending vibration of the isotopomer (in and
Freeze-thaw lysates of Plasmodium falciparum-infected red blood cells induce differentiation of functionally competent regulatory T cells from memory T cells.
No full textIn addition to naturally occurring regulatory T (nTreg) cells derived from the thymus, functionally competent Treg cells can be induced in vitro from peripheral blood lymphocytes in response to TCR stimulation with cytokine costimulation. Using these artificial stimulation conditions, both naïve as well as memory CD4(+) T cells can be converted into induced Treg (iTreg) cells, but the cellular origin of such iTreg cells in vivo or in response to more physiologic stimulation with pathogen-derived antigens is less clear. Here, we demonstrate that a freeze/thaw lysate of Plasmodium falciparum schizont extract (PfSE) can induce functionally competent Treg cells from peripheral lymphocytes in a time- and dose-dependent manner without the addition of exogenous costimulatory factors. The PfSE-mediated induction of Treg cells required the presence of nTreg cells in the starting culture. Further experiments mixing either memory or naïve T cells with antigen presenting cells and CFSE-labeled Treg cells identified CD4(+) CD45RO(+) CD25(-) memory T cells rather than Treg cells as the primary source of PfSE-induced Treg cells. Taken together, these data suggest that in the presence of nTreg cells, PfSE induces memory T cells to convert into iTreg cells that subsequently expand alongside PfSE-induced effector T cells
Astroenzymology – the environmental limits of enzyme activity
No full textUsing organisms from extreme terrestrial environments as models for extraterrestrial life may lead us to underestimate the range of environments that life may inhabit. An alternative approach is to inspect the range of conditions over which crucial biomolecules might function. Recent investigations of enzyme activity suggest that they have the potential to function over a wider range of environmental conditions than expected. Although the upper temperature limit for enzyme stability is unclear, some enzymes are active up to 130°C. The evidence is that the instability of enzymes is a functional requirement, rather then because of any restraint on achieving higher stability. There is no evidence that enzyme activity ceases at low temperatures; it declines in a predictable manner to the lowest temperature at which it has been possible to make measurements, -100°C. It has been generally accepted that dehydration stops enzyme activity but this acceptance may have arisen partly from the technical difficulty of assessing enzyme activity without a fluid medium for diffusion. Experiments using anhydrous organic solvents or gas phase substrates suggest activity occurs in enzymes at very low hydration
Management styles and their impact on employee motivation in organization “OC Vision”.
No full textBakalaura darba tēma ir “Vadības stili un to ietekme uz darbinieku motivāciju organizācijā “OC Vision””. Organizācijā ir svarīgi uzņēmumā katram vadītājam izvēlēties pareizo vadības stilu. Pareiza stila izvēle sekmē organizācijas darbību un ļauj vadītājam ar savu komandu ātrāk sasniegt rezultātus un tuvoties mērķu izpildei. Bakalaura darba mērķis ir izpētīt, izanalizēt un salīdzināt kādi vadības stili ir vadītājiem, kuri strādā uzņēmumā “OC Vision” un kā viņu vadības stils ietekmē darbinieku motivāciju, izstrādāt priekšlikumus vadības stila izvēlei šajā uzņēmumā, lai to darbinieki būtu pēc iespējas motivētāki. Darbs sastāv no 3 nodaļām. Pirmajā nodaļā darba autors sniedz ieskatu darba teorijā par vadītāju lomu organizācijā, vadības stiliem, kā arī vadītāja un darbinieka attiecībām. Otrajā nodaļā darba autors sniedz ieskatu darba teorijā par motivāciju un motivācijas teorijām. Trešajā nodaļā darba autors apkopo datus no aptaujā iegūtajiem rezultātiem. Nobeigumā ir izstrādāti secinājumi un sniegti priekšlikumi, izmantotās literatūras saraksts un pielikumi. Bakalaura darbs sastāv no 63 lappusēm, kurās ir 13 attēli, 21 tabula un 1 pielikums.The theme of the Bachelor`s thesis is “Management styles and their impact on employee motivation in organization “OC Vision””. In an organization, it is important for each manager to choose the right management style. Choosing the right style facilitates the operation of the organization and allows the manager with his team to achieve results faster and approach goals. The aim of the bachelor's thesis is to study, analyze and compare which management styles are for managers working in the company "OC Vision" and how their management style affects employee motivation, develop proposals for the choice of management style in this company so that their employees would be as motivated as possible. The Bachelor’s thesis consists of three chapters. In the first chapter, the author provides an insight into the theory of work on the role of managers in the organization, management styles, and the relationship between manager and employee. In the second chapter, the author provides an insight into work theory on motivation and motivation theories. In the third chapter, the author summarizes the data from the results of the survey. In the end are conclusions and proposals, a list of references and appendix The Bachelor`s thesis consists of 63 pages, 13 photos, 21 tables and 1 appendix
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