Exploration in the Rukwa rift, using gravity and seismic reflection surveys, fieldwork, and drilling has defined the structure and stratigraphy of the basin in greater detail than any other part of the Western rift. The stratigraphy comprises Precambrian basement, Karroo sandstones, shales and coals, upper Miocene red beds, and Miocene‐Recent lacustrine and fluvial sediments. During Miocene‐Recent rifting the greatest sediment input apparently came from axial fluvial systems flowing from the northwest and southeast. The southwestern area experienced alternating shallow lacustrine and fluviodeltaic conditions during the Miocene‐Recent. Cenozoic age rift structures have a dominant NW‐SE and a subordinate N‐S trend. The NW‐SE trend tends to follow a Precambrian basement and later Karroo structural trend. NE‐SW seismic lines indicate up to 10 km extension of the Tertiary section in a direction oblique to the probable E‐W regional extension direction. In the southeastern portion of the basin both Karroo and Tertiary‐Quaternary sediments expand into the Lupa fault zone, reaching thicknesses of up to 3 and 7 km, respectively. Tertiary‐Quaternary sediment thicknesses decrease northwestward, accompanied by a decrease in the amount of extension and a broadening of the basin as extension is transferred to the Lake Tanganyika rift.

Phosphorus and K fertilization increases alfalfa (Medicago sativa L.) yield and stand persistence, but the changes in yield components as affected by P and K fertility level are not known. Our hypothesis is that P and (or) K fertilization will increase one or more alfalfa yield components, and those component responses may change with stand age. The objectives of this field study were to determine the impact of P and K fertilization on alfalfa forage yield and yield components during the initial 3 yr after establishment. Treatments were the factorial combinations of four P rates (0, 25, 50, and 75 kg P ha−1) and five K rates (0, 100, 200, 300, and 400 kg K ha−1) arranged in a randomized complete block design with four replications. Forage harvests occurred four times annually, and yield, mass shoot−1, and shoots area−1 were determined. Plant populations were determined in early December and late May each year. Incremental additions of P and K increased alfalfa yield in each year. Potassium fertilization did not influence plant population, while robust P‐responsive alfalfa plants apparently crowded out smaller, less vigorous plants thus decreasing plants m−2 Stand assessments based on shoot counts, or aboveground plant counts may not accurately indicate alfalfa yield potential. Shoots plant−1 was not affected by application of either nutrient, while shoots m−2 generally declined with increased P and K fertilization. Improved forage yield of P‐ and K‐fertilized plots was consistently associated with greater mass shoot−1 Because fertilizer‐responsiveness is closely associated with greater mass shoot−1, cultivars possessing this trait may be relatively more productive under well‐fertilized conditions.

Cold hardiness among zoysiagrass (Zoysia spp.) genotypes varies, but the physiological basis for cold hardiness is not completely understood. The objective of this study was to determine the relationship of carbohydrate (starch, total soluble sugars, total reducing sugars, sucrose, glucose, and raffinose family oligosaccharides) and proline concentrations with the cold acclimation of zoysiagrass and the lethal temperature killing 50% of the plants (LT50). Thirteen genotypes of zoysiagrass were selected with contrasting levels of winter hardiness. Plants were grown for 4 wk of 8/2°C day/night cycles and a 10‐h photoperiod of 300 μmol m−2 s−1 to induce cold acclimation. Rhizomes and stolons were sampled from nonacclimated and cold‐acclimated plants and used for carbohydrate and proline analysis. Concentrations of soluble sugars and proline increased during cold acclimation, while starch concentrations decreased. Starch, sugar/starch ratio, glucose, total reducing sugars, and proline in cold‐acclimated plants were correlated (r = 0.61, −0.67, −0.73, −0.62, and −0.62, respectively) with LT50 These correlations indicate that higher concentrations of total reducing sugars, glucose, and proline are positively associated with zoysiagrass freeze tolerance, whereas higher concentrations of starch appeared detrimental to freeze tolerance.

Fall dormancy is correlated with improved winter survival in alfalfa (Medicago sativa L.), but the physiological basis for this association is not understood. Our objectives were to determine how selection for contrasting fall dormancy influenced (i) fall height and winter survival, (it) crown bud development, and (iii) sugar, starch, protein concentration and composition of roots and crown buds. Three cycles of selection for contrasting fall dormancy were conducted in Davis, CA using ‘Norseman’, ‘Lahontan’, ‘CUF 101’, and ‘Wadi Qurayat’ as parental sources. Seed of parental cultivars and seed of progeny from the third cycle of selection were planted in rows in the field (Starks‐Fincastle, fine‐silty, mixed, mesic Aerie Ochraqualf) West Lafayette, IN, in May 1993 and 1994, and roots and crown buds were sampled at approximately monthly intervals between September and December. Plant survival was determined in March of the year following seeding. Parental cultivar differences in fall dormancy and winter survival were associated with changes in crown bud development, elevated total nonstructural carbohydrate and sugar concentrations in buds, and sugar and protein accumulation in roots. Cultivar differences in fall dormancy also influenced polypeptide composition of green buds and roots. Selection for greater fall dormancy reduced the height of CUF 101 and markedly improved its winter survival. Concentrations of sugars and proteins in buds and roots of the dormant selection of CUF 101 increased to values similar to those observed for the fall‐dormant, winter‐hardy Norseman. Selection solely for contrasting fall dormancy can alter cold acclimation in buds and roots and winter survival of alfalfa.

Background: The United States Food and Drug Administration is investigating possible diet-associated dilated cardiomyopathy (DCM) in dogs and cats. Objectives: To retrospectively review DCM cases for signalment, diet information, echocardiographic changes, and survival.