Shape transition of germanium nanocrystals on a silicon (001) surface from pyramids to domes

Chemical vapor deposition of germanium onto the silicon (001) surface at atmospheric pressure and 600 degrees Celsius has previously been shown to produce distinct families of smaller (up to 6 nanometers high) and larger (all approximately 15 nanometers high) nanocrystals. Under ultrahigh-vacuum conditions, physical vapor deposition at approximately the same substrate temperature and growth rate produced a similar bimodal size distribution. In situ scanning tunneling microscopy revealed that the smaller square-based pyramids transform abruptly during growth to significantly larger multifaceted domes, and that few structures with intermediate size and shape remain. Both nanocrystal shapes have size-dependent energy minima that result from the interplay between strain relaxation at the facets and stress concentration at the edges. A thermodynamic model similar to a phase transition accounts for this abrupt morphology change.     

A kuroko-type polymetallic sulfide deposit in a submarine silicic caldera

Manned submersible studies have delineated a large and actively growing Kuroko-type volcanogenic massive sulfide deposit 400 kilometers south of Tokyo in Myojin Knoll submarine caldera. The sulfide body is located on the caldera floor at a depth of 1210 to 1360 meters, has an area of 400 by 400 by 30 meters, and is notably rich in gold and silver. The discovery of a large Kuroko-type polymetallic sulfide deposit in this arc-front caldera raises the possibility that the numerous unexplored submarine silicic calderas elsewhere might have similar deposits.     

Effects of organic manure and chemical fertilizer on soil fertility and productivity of plant and ratoon crops of sugarcane

A long-term field experiment was initiated in November, 1967 at Research Area of Department of Soil Science to study the response of nitrogen to pearl millet-wheat cropping system at various doses and modes of farmyard manure application. The soil organic carbon increased with farmyard manure application and ranged from 0.68% in control to 1.82% in the plot receiving the highest annual dose (90 Mg ha^?1) of farmyard manure. To study the contribution of farmyard manure on the productivity of pearl millet and wheat crops, the constants (intercept and slope) were determined between the grain yield of pearl millet and wheat crops with increasing dose of fertilizer nitrogen. Another linear regression was fitted between the intercept of the linear model and the soil organic carbon content. It has been observed that with each unit increase in the soil organic carbon, the productivity of pearl millet increased by 273 kg ha^?1 and that of wheat by 1591 kg ha^?1. The regression between the slope and soil organic carbon was linear in case of pearl millet (R² 0.49) but in case of wheat there was no relationship.     

An integrative insight into the synsacral canal of fossil and extant Antarctic penguins

The lumbosacral-canal system in birds most likely operates as a sense organ involved in the control of balanced walking and perching, but our knowledge of it is superficial. Penguins constitute interesting objects for the study of this system due to their upright walking, but only the Humboldt penguin, Spheniscus humboldti, and some incomplete fossil penguin synsacra have been studied in this respect. Here, we give an integrative comparative insight into the synsacral canal of extant Emperor penguin, Aptenodytes forsteri, Adelie penguin, Pygoscelis adeliae, and Eocene giant Anthropornis and/or Palaeeudyptes Antarctic penguins, using computed tomography imaging and associated data-extraction methodologies, complemented by analytical approaches ranging from geometric morphometrics to modularity, curvature, and wavelet analyses. We document that the variability in the number of synsacro-lumbar vertebrae is evolutionarily conserved, and all studied synsacra possess osteological correlates of the lumbosacral-canal system. We also found that Eocene and extant Antarctic penguins were separable on the basis of the main direction of the shape-related (size-independent) variability within said system, and A. forsteri was unique in the entire studied set in terms of the relative cranial shift of this compound structure. Moreover, we suggest that the evolutionary processes, shaping both the terrestrial posture and gait, were responsible, in extant penguins, for the increased simplicity and stability of the synsacral canal cross-sectional periodic patterns, as well as pave the way for the lumbosacral-canal system modularity characterized by reduced atomization/complexity.     

Therapeutic percutaneous ultrasound-guided cholecystocentesis in three dogs with extrahepatic biliary obstruction and pancreatitis

Three dogs were examined because of acute pancreatitis. In all 3, distension of the gallbladder was seen ultrasonographically, and extrahepatic biliary tract obstruction (EHBO) was diagnosed on the basis of ultrasonographic findings and serum biochemical abnormalities (i.e., high serum bilirubin and cholesterol concentrations and increased hepatic enzyme activities). In all 3 dogs, percutaneous ultrasound-guided cholecystocentesis (PUCC) was used to decompress the gallbladder, with cholecystocentesis performed multiple times in 1 dog. Serum bilirubin concentration was substantially decreased following the procedure in all 3 dogs. Two of the 3 dogs did not require surgery to resolve the obstruction. In the third dog, an exploratory laparotomy was performed because of concerns about development of abdominal effusion following the procedure. Bile staining of the mesenteric fat was seen during the laparotomy, but no defect in the gallbladder wall could be identified. In most dogs with EHBO secondary to pancreatitis, the obstruction resolves spontaneously as the acute pancreatitis improves so that surgery is not required. In those few dogs in which EHBO does not resolve or in which EHBO results in complications, therapeutic PUCC may be useful in relieving gallbladder distension.     

Type II Supernova Matter in a Silicon Carbide Grain from the Murchison Meteorite

The circumstellar silicon carbide (SiC) grain X57 from the Murchison meteorite contains large amounts of radiogenic calcium-44 (20 times its solar system abundance) and has an anomalous silicon isotopic composition, different from other circumstellar SiC grains. Its inferred initial 44Ti/Si and 44Ti/48Ti ratios are 1.6 x 10(-4) and 0.37. In addition, it contains radiogenic magnesium-26; the inferred initial 26Al/27Al ratio is 0.11. The isotopic and elemental data of X57 can be explained by selective mixing of matter from different zones of a typical type II supernova of 25 solar masses during its explosion. The high 44Ti/Si ratio requires contributions from the innermost nickel zone of the supernova to the SiC condensation site, as similarly suggested by astronomical observations.     

Profiling the New Zealand Thoroughbred racing industry. 2. Conditions interfering with training and racing

AIM: To describe and enumerate conditions that interrupted training and racing in a population of Thoroughbred racehorses in New Zealand.

METHODS: A longitudinal study design was used to collect data on horses training under the care of 20 licensed racehorse trainers from venues in the mid to lower regions of the North Island between October 1997 and July 2000. Incidence rates were reported for first and second occurrences for different categories of musculoskeletal injury (MSI), and first occurrences of upper and lower respiratory tract disease, using training days as time-at-risk. The proportion of horses that retired or died due to MSI, respiratory tract or miscellaneous conditions was used to estimate risk of exit for each type of event. Duration of training preparation, starts per 100 training days, and proportion of starts that ended in first, second or third place, were calculated for horses at risk for first MSI, and all subsequent MSIs. In training preparations that had at least one start and that ended in MSI, the cumulative percentage of MSIs by day of diagnosis was reported for 0–21 days after the last start in the preparation.

RESULTS: Horses (n=1,571) were followed during 3,333 training preparations and 392,290 training days. Events associated with the end of a training preparation or spell period included MSI (n=834), respiratory event (RE; n=165), miscellaneous event (ME; n=58), and voluntary retirements (n=360). Causes of MSI included lameness (n=400), shin soreness (n=207), tendon and ligament conditions (n=98), injury or laceration (n=56), fractures (n=55), and back disorders (n=18). MSIs involved the limbs in 97% of cases, and the lower limbs up to the carpus or hock in the fore- and hindlimbs, respectively, in 81% of cases. Most (93%) lower limb conditions involved a forelimb while 70% of MSIs that involved structures above the carpus or hock involved a hindlimb. Incidence rates (IRs) are reported for each age group for first and second occurrences of MSI, and first occurrence of upper and lower respiratory tract disease. The risk of MSI was higher in horses that had incurred one previous MSI (RR 1.4, 95% CI=1.2–1.7; p>0.001) than in horses without any previous MSI. The proportion of horses that exited due to death or retirement varied with the type of injury, and the highest proportion was associated with recurrent fractures, and tendon and ligament injuries (46.2 and 44.4%, respectively). The overall IR of horses exiting the study due to retirement or death increased with increasing age, and was higher in females than males for horses aged 2, 3, 4, and ≥5 years. A reduction in the number of starts per 100 training days was observed in horses aged ≥5 years when returning to training after an initial MSI (p=0.004). Male horses of all age groups and females younger than 4 years had shorter median training preparations (p>0.05) when returning to training after an initial MSI compared with preparations at risk for a first occurrence of MSI. Between 27 and 62% of cases of MSI that occurred in training preparations after at least one start were reported on the day of the last start, and the remainder were reported in the days to weeks following the last start of that preparation.

CONCLUSION: Incidence rates, and proportions of affected horses that retired or died as a result of injury or disorder varied with type of injury and age of horse. Horses returning to training after an initial MSI were at higher risk of subsequent MSIs and showed changes in duration of training preparations, but little change in starts per 100 training days or probability of placing in each start. MSIs in racing horses were less likely to be reported on the day of a race than at other times in the training preparation for all ages except 2-year-olds.