Compressional and shear body waves generated by a seismic source can be analyzed using vertical seismic profiling (VSP) data-acquisition procedures. If a goal of exploration geophysics is to study the physics and exploration applications of shear waves, it is important to know how much S-wave energy a source puts into the earth. To maximize S-wave created by a source, considerable effort has been expended to create surface sources that apply horizontally directed impulses to the earth (horizontal vibrators and horizontal impacts). In my project, radial shear (SR) and transverse shear (ST) waves generated by different types of sources and recorded by multicomponent receivers in a VSP well are examined and compared. The research question is ‘can a vertical-impact source create shear wave energy equivalent to the S-wave energy produced by standard horizontal-force shear-wave sources?’ To quantify the energy of shear-wave modes produced by different kinds of seismic sources, a VSP field test program was conducted at the Devine Test Site owned by The University of Texas at Austin. In the VSP data acquisition phase, the orientation of horizontal geophones is unknown because a borehole geophone rotates as it is lowered into a well, causing the horizontal geophones at each receiver station to be oriented in different azimuths. To study body waves, it is essential that all geophones in a vertical VSP array be oriented in a consistent azimuth. I mathematically rotated multi-component VSP sensors systems to change them from the inconsistent orientation they had at the time of data recording to a user-defined consistent-azimuth coordinate system. This rotation allowed ST and SR wave modes to be identified. After geophone rotation, direct-S wavelet amplitudes were analyzed in 90-ms windows starting at the first-break times of each arriving mode. Analysis of the rotated data showed that SR energy created by a vertical-impact source, a shot-hole explosive, and an inclined-impact source differ only slightly, and that there is essentially no difference in ST energy among these sources. Also, the signal frequency of SR and ST wave modes produced by horizontal-force shear wave sources are essentially the same as the frequency of SR and ST wave modes generated by a vertical-impact source. These test data show that vertical and horizontal vibrator sources produce shear wave modes having amplitudes 1000 times stronger than the other energy sources we tested. Considering the cost of using inclined-impact sources which is relatively expensive compared to using a vertical-impact source, and the difficulty of applying inclined-impacts in some land conditions, it is possible to obtain direct-S data of the same quality by using only a vertical-impact source or a shot-hole explosive. The arguments given above demonstrate that it is not necessary to use inclined-impact sources or horizontal vibrators to produce shear-wave data. S-wave data of the same quality produced by a horizontal-force source are provided by simple vertical-impact sources and shot-hole explosives. / text

I analyse an x-ray selected sample of 128 late-type (F-M) stars. These stars were identified as optical counterparts to serendipitous x-ray detections made by the Einstein Observatory Extended Medium Sensitivity Survey. Once identified as x-ray sources, the stars were reobserved with an extensive program of optical observations consisting of high- and low-resolution spectroscopy and photometry. Spectral types, luminosity classes, absolute magnitudes, distances, x-ray luminosities, projected rotation rates (v sin i), radial velocities, and binary status have been determined for the sample. I find that Lₓ is correlated with v sin i for single stars. However, Lₓ does not correlate with Ω sin i, which leads me to believe that the correlation seen with v sin i is actually a correlation with radius. Indeed, Lₓ correlates strongly with radius (color, mass) for main sequence stars. This result provides a plausibility argument for rotational saturation in the coronae of late-type stars. Since this sample is flux limited, I use sky coverage and sensitivity information from the Einstein Observatory to calculate the bright end of the x-ray luminosity function for late-type stars. It appears that previously calculated luminosity functions from optically selected samples have underestimated the number of x-ray bright F and G dwarfs. I have also discovered 8 previously uncatalogued M dwarfs within 25 pc of the sun. My sample includes only M dwarfs of spectral type M5 and earlier, 93% of which are "emission" stars (i.e. type Me V), as well as two pre-main sequence M stars. Arguments involving kinematics and stellar rotational velocities are used to estimate the age of these x-ray "bright" M dwarfs; they appear to be quite young (≤ 1-3 x 10⁹ yrs). Since the local space density of x-ray "bright" M dwarfs increases with mass, I infer a longer activity timescale for lower masses. M dwarfs later than M5 lie below the sample's x-ray sensitivity limit. An upper limit of log Lₓ = 27.45 is put on their coronal emission. I also present H(α) and Ca II K line fluxes for most members of the M dwarf sample and show that the H(α) and Ca II K luminosities do indeed correlate with Lₓ. However, these chromospheric luminosities are weaker functions of rotation than Lₓ and may, in fact, represent saturated levels of activity. My results are consistent with the hypothesis that the chromosphere is heated by x-rays from the overlying corona. Finally, I discuss two unusual members of the sample which are attractive candidates for the recently proposed class of FK Comae stars.

High resolution rotational spectra of ¹⁰BH₃CO, ¹¹BH₃CO, ¹¹BD₃CO, PH₂D and CD₃CN were studied to obtain information concerning the electronic and magnetic properties of these molecules. From the analysis of the hyperfine structure of the rotational spectra of the molecules the following constants were determined: rotational constants (B₀), nuclear quadrupole coupling constants (eOq [x], spin-spin constants D (X-Y) and spin rotation constants (C[x]). The two instruments used in these experiments were a Stark modulated microwave spectrometer and a molecular beam maser spectrometer. The J = 0 to 1, F₁ = 3 to 3 and F₁ = 3 to 4 transitions of ¹⁰BH₃CO were studied. The molecular constants in KHz which were derived from the spectral analysis were: B(,0) = 8980060.3 (+/-) 1.0, eQqₐₐ (¹⁰B) = 3463.- (+/-) 8.0, C(¹⁰B) = .2 (+/-) .2, D(¹⁰B-H) = -2.8 (+/-) .2, D(H-H) = -7.2 (+/-) .5 and C(H) = 0.0 (+/-) .7. All three of the F₁ components of the J = 0 to 1 rotational transition of ¹¹BH₃CO were observed. The molecular constants in KHz which were obtained from the data analysis were: B₀ = 8657333.8 (+/-) .6, eQqₐₐ (¹¹B) = 1661.9 (+/-) 2.3, C(¹¹B) = .7 (+/-) .3, D(¹¹B-H) = 8.3 (+/-) .4, D(H-H) = -6.8 (+/-) .2 and C(H) = .4 (+/-) .4. Only spectra of the J = 0 to 1, F₁ = 3/2 to 3/2 transition of ¹¹BD₃CO were obtained. From the analysis of the spectra the following molecular constants were derived: eQqₐₐ (D) = -48.5 (+/-) 2.3, eQq(,zz)(D) = 116.9 (+/-) 5.4, C(D) = 0.0 (+/-) .8 and D(¹¹B-H) = -1.2 (+OR-) .3. The investigation of the 4₀₄ to 4₁₄ and 1₁₁ to 1₀₁ rotational transitions of PH₂D was unsuccessful in determining any molecular parameters. The spectra of the 4₀₄ to 4₁₄ rotational transition were not amenable to analysis and no spectra were obtained for the 1₁₁ to 1₀₁ rotational transitions. The three components of the J = 0 to 1 rotational transitions of CD₃CN were studied with the maser in the two cavity configuration. The constants in KHz which were determined were: B₀ = 7857978.7 (+/-) .1, eQqₐₐ(N) = -4229.2 (+/-) .6, eQqₐₐ(D) = -55.1 (+/-) .4, eQq(,zz)(D) = 165.5 (+/-) 5.0, C(,N) = 1.7 (+/-) .1 and C(,D) = 0.0 (+/-) .03.

ABSTRACT Legumes are becoming increasingly important in cropping systems due to their beneficial effects on soil nutrient availability. Including legumes into a cropping system not only positively affect many soil physical properties and increases soil nitrogen (N) supply, but is also reported to have a positive impact on soil phosphorus (P) availability. Although a series of studies have examined the effect of grain legumes in rotation on increasing soil N and P fertility after several years, the effect of forage legumes like alfalfa (Medicago sativa L.) and red clover (Trifolium pratense L.) on soil P availability, the yield and P uptake of subsequently grown crops remain unknown in Western Canada. To address this gap, a four year field experiment was conducted in four soil zones of Saskatchewan: Dark Brown soil zone (Saskatoon), thin Black soil zone (Lanigan), Brown soil zone (Swift Current), and Gray soil zone (Melfort). The objectives of this study were (i) to evaluate the impact of including a two-year period of forage legumes alfalfa (Medicago sativa L.) and red clover (Trifolium pratense L.) along with annual crops on soil P forms, amounts and availability and uptake of P by the crops in rotation and (ii) to evaluate the effect of the different crop rotations over the four years on soil P dynamics and P balance. After two years of forage legume and annual crop rotations, it was observed that alfalfa and red clover removed more P from the soil in the hay harvest as compared to the amount of P removed in grain in the barley (Hordeum vulgare L.) - pea (Pisum sativum L.) and barley (Hordeum vulgare L.) - flax (Linum usitatissimum L.) rotations at all four sites (P < 0.10). However, the four crop rotations did not significantly affect the amount of soil available P and P supply rate at all four sites (P > 0.10) despite greater P uptake and removal by forage legumes relative to annual crops in 2010 and 2011 growing seasons. Also, similar amounts of labile and stable P were measured in the different sequentially extracted chemical fractions after two years of different crop rotations at all sites (P > 0.10). Grain yields of wheat (Triticum aestivum L.) and canola (Brassica napus L.) crops grown following two years of forage legume and annual crop rotations were positively affected by forage legume rotations at Saskatoon, Lanigan and Melfort (P < 0.10). Wheat P uptake was improved significantly by two years of red clover at Lanigan, Swift Current and Melfort (P < 0.10) but canola P uptake was not affected by different crop rotations at all locations (P > 0.10). The amount of soil available P and P supply rate measured after wheat and canola harvest were not affected by different crop rotations at all sites (P > 0.10) despite the greater P removal by forage legumes during the first two years of the four year crop rotation period at all sites and the enhanced P removal by wheat and canola crops following forage legume rotations at Lanigan and Melfort. This suggests that forage legumes are able to maintain soil P fertility in the face of greater P removal by crops in rotation, at least in the short-term. Four years of continuous cropping with the minimum amount of fertilizer P addition resulted in a significant reduction of soil P fertility over time at all locations (P < 0.10). The lack of a significant effect of rotation treatment on available P levels in the soil does not rule out that there is an effect but variability prevented its detection. Further research is needed to evaluate the effects of several cycles of this rotation over a number of years on soil P availability and the P uptake of crops in rotation.

Previous investigations comparing direct versus indirectly cued movements have consistently shown that indirectly cued movements take longer to prepare (Neely and Heath, 2010) and involve the recruitment of additional brain areas (Connolly et al., 2000). This increase in processing time has been associated with the additional cognitive transformations required of the task (Neely and Heath, 2010). In the present study we investigated whether differences between direct versus indirectly cued movements are also reflected in the time course of motor preparation. Participants performed a targeting task, moving directly to the location of a visual cue (i.e., directly cued movement) or to a location that differed by 60˚, 90˚, or 120˚ with respect to the visual cue provided (i.e., indirectly cued movements). Participants were instructed to initiate their movements concurrently with an anticipated go-signal. To examine the time course of motor preparation, a startling acoustic stimulus (SAS, 124dB) was randomly presented 150 ms, 500 ms, or 1000 ms prior to the go-signal. Results from the startle trials revealed that the time course of motor preparation was similar regardless of the angle of rotation required and hence whether it was a direct or indirectly cued trial. Specifically, motor preparation was delayed until less than 500 ms prior to movement initiation for both direct and indirectly cued movements. These findings indicate that similar motor preparation strategies are engaged for both types of cued movements, suggesting that the time to prepare a motor response may be similar regardless of whether a cognitive transformation is required.

Sanders, Donald W. The University of Manitoba, March, 2017. The effect of preceding crop on soybean (Glycine max) grain yield, mycorrhizal colonization, and biological nitrogen fixation. Major Professor:Yvonne Lawley. Manitoba has seen a twenty-fold increase in soybean acres seeded since 2000, with over 1.6 million acres seeded in 2016. This change presents unique opportunities and challenges to improve crop rotations in Manitoba. This experiment studied the effect of four crop sequences on soybean yield, mycorrhizal colonization, and biological nitrogen fixation. In the first year of this experiment, spring wheat, canola, corn and soybeans were grown at three sites in Manitoba (Carman, Portage la Prairie, and Kelburn). In the second year, soybeans were grown on these same plots as a test crop. This two-year sequence of crops was done twice at each site, in 2012-13 and 2013-14. To determine mycorrhizal colonization, root samples were collected at the V3 stage and then analyzed microscopically for mycorrhizal infection. Nitrogen fixation was estimated using the natural abundance method using soybeans collected at the R5 and R6 stage and canola as a reference crop. Soybean following soybean had significantly higher grain yield than all other crop sequences at one site year, and significantly lower grain yield than all other crop sequences at another site year. There were no other differences in soybean test crop yield between crop sequences. Crop sequence significantly affected mycorrhizal colonization. Soybean following canola had significantly lower mycorrhizal colonization than soybean following soybean or corn. Soybean following spring wheat also had significantly lower mycorrhizal colonization than soybean following soybean or corn. Soil test phosphorus levels also significantly affected mycorrhizal colonization, with increasing soil phosphorus resulting in decreased mycorrhizal colonization. Crop sequence significantly affected biological nitrogen fixation. Soybean following soybean or corn often had significantly greater biological nitrogen fixation than soybean following spring wheat or canola. Soil test nitrate levels affected biological nitrogen fixation, with increasing soil nitrate resulting in decreased biological nitrogen fixation. Soil test nitrate levels were affected by the carbon to nitrogen ratio of the preceding crop, with a higher carbon to nitrogen ratio associated with decreased soil nitrate. These results indicate that although there is often not a yield penalty associated with specific rotations, crop sequence has a strong impact on mycorrhizal colonization and biological nitrogen fixation. The soil organisms associated with those processes affect soil phosphorus uptake and nitrogen fixation. Producers should consider the importance of crop rotation when seeking to maximize productivity through symbiotic processes with mycorrhizae and nodule forming bacteria. / May 2017

Molecular rotational motions are known to influence both Raman scattering of light and nuclear spin relaxation. Therefore, the application of Raman bandshape analysis and NMR relaxation time measurements to probe molecular dynamics in liquids will provide us with a deeper understanding of the dynamical behavior and structure of molecules in the liquid phase. Presented here are (i) studies of molecular reorientation of acetonitrile in the neat liquid phase and in solution by Raman bandshape analysis and NMR relaxation; (ii) studies of reorientational dynamics and internal rotation in transition metal clusters by NMR relaxation.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

No description available.

No cenário olerícola nacional, a produção de batata está em crescimento. Nas áreas produtoras de batata das regiões Sul e Sudeste é comum encontrar essa cultura em rotação com milho e trigo. O uso de alguns herbicidas do grupo químico das sulfoniluréias nas culturas anteriores tem causado sintomas de fitointoxicação nas lavouras de batata. As deformações dos tubérculos ocorrem no inicio da fase de tuberização, quando se nota numerosas rachaduras relacionadas à contaminação por sulfoniluréias. O objetivo deste trabalho de pesquisa foi avaliar a resposta de plantas de batata das cultivares Atlantic e Lady Rosetta, quanto à produtividade e qualidade dos tubérculos, submetidas a aplicação de subdoses dos herbicidas metsulfuron-methyl e nicosulfuron, utilizados nas culturas do trigo e milho respectivamente. O experimento foi instalado em condições de campo. Os herbicidas foram aplicados nas plantas de batata no início da fase de tuberização. A fitointoxicação causada pelos herbicidas foi avaliada na parte aérea, na produtividade e qualidade dos tubérculos. Ambas as sulfoniluréias, metsulfuron-methyl e nicosulfuron, causaram injúrias foliares nas cultivares de batata, sendo que na cultivar Atlantic esses sintomas não predizem os danos nos tubérculos, que foram inferiores aos esperados. As sulfoniluréias reduziram a produção de tubérculos de maior diâmetro em ambas as cultivares. A cultivar Atlantic teve redução na produção e produtividade causadas pela pulverização de nicosulfuron na dose recomendada para a cultura do milho, e não foi afetada pelas pulverizações de metsulfuron-methyl. A cultivar Lady Rosetta foi afetada por ambas as sulfoniluréias nas maiores doses e pelo nicosulfuron também em dose 10 vezes menor àquela recomendada para a cultura do milho. A produção de tubérculos inviáveis na cultivar Atlantic foi devido à incidência de rachaduras, podendo chegar a 16,11% com a pulverização de metsulfuron-methyl e até 91,33% com nicosulfuron. Na cultivar Lady Rosetta a produção de tubérculos inviáveis caracterizou-se por sintomas de distúrbios fisiológicos, chegando até 78,26% e 88,44% com pulverização de metsulfuron-methyl e nicosulfuron respectivamente. As cultivares Atlantic e Lady Rosetta não perderam produtividade nem qualidade dos tubérculos após aplicação de metsulfuron-methyl ou nicosulfuron nas subdoses testadas. / Potato production increases in the brazilian horticultural scene. Its common to find this crop in rotation with wheat and maize in the south and southeast production areas in Brazil. The use of some sulfonylureas herbicides in previous crops might cause phytotoxicity symptoms in potato. Tuber malformation take place in the beginning of tuberization, when can be noted tuber cracking related to sulfonylureas contamination. This trial aimed to assess the tuber quality and productivity of potato cultivars Atlantic and Lady Rosetta, subjected a application of low ates of metsulfuron-methyl and nicosulfuron, used previously in wheat and maize crops respectively. The trial was carried out in field conditions. The herbicides were sprayed in potato plants in the beginning of the tuberization phase in different rates. The sulfonylureas phytotoxicity was evaluated in the vegetative part and in the tuber quality and yield. Sulfonylureas, metsulfuron-methyl and nicosulfuron, caused foliar injuries in the potato cultivars, being that in Atlantic cultivar these symptoms do not predict tuber damages, that was below expectations. The sulfonylureas also reduced the production of tubers with larger caliber. The Atlantic cultivar decreased the production and the yield because of the nicosulfuron sprayed in maize recommended dose but was not affected by metsulfuronmethyl treatments. The Lady Rosetta cultivar was affected by both of sulfonylureas in the highest doses, such recommended for other crops, and also by nicosulfuron ten times diluted. The production of tuber unachievable for commercialization by the Atlantic cultivar was due to cracking, leading to 16.11% of cracked tubers after metsulfuronmethyl spray and 91.33% with nicosulfuron. In the Lady Rosetta cultivar it was characterized by malformation and second growth, achieving 78.26% and 88.44% of deformed tubers after metsulfuron-methyl and nicosulfuron sprays respectively. Both of the cultivars did not reduce tuber quality and yield after pulverization of metsulfuronmethyl or nicosulfuron in those low rates tested.