断根和覆草旱作条件下水稻的产量效应

通过大田对比试验研究了常规水稻与覆草旱作水稻的产量构成、根系呼吸强度以及断根对产量的影响。 结果表明,覆草旱作水稻籽粒产量(5850.9 kg/hm[sup]2[/sup])明显低于常规水稻（6685.7 kg/hm[sup]2[/sup]）,但前者的秸秆产量(5735.5 kg/hm[sup]2[/sup])高于常规水稻(5489.5 kg/hm[sup]2[/sup])。常规水稻实粒占平均单蘖总量的百分数远大于覆草旱作水稻,覆草旱作水稻叶、鞘、秕粒的比例大于常规水稻。覆草旱作的根冠比（0.116）显著大于常规水稻（0.087）,前者的根系呼吸强度是常规水稻的2.7倍。旱作水稻断根后普遍有增产的趋势,而常规水稻则有减产的趋势。常规水稻断1/4、2/4和3/4根系时,平均每穴籽粒产量较不断根的分别下降23％、15％和20％。然而,旱作条件下,断1/4、2/4和3/4根系的水稻较全根的分别增产20％、7％和3％。由此可见,水稻旱作抑制了同化产物向籽粒的转运,叶和鞘中积累了较多的同化产物;旱作水稻根系冗余生长,消耗了大量碳水化合物,可能导致水稻籽粒产量下降。     

Analysis of Local Sales Taxation in Rural Areas: An Oklahoma Case Study

This study examines the impact of tax rates and tax rate differentials in a trade area on local sales tax revenues. Sales data for FY 1986 were analyzed for the 75 nonmetropolitan communities in Oklahoma with populations between 2,500 and 50,000. Multiple regression techniques were used to estimate local tax revenues as a function of tax rates, tax rate differential and local community economic and locational attributes. The results indicate that the tax rate differential was not significantly related to local revenue collection in the overall sample, but that the differential was significant for rural communities with relatively higher tax rates. Tax rate, income, service sector employment and a gravity factor were also significant influences on local sales tax revenues. These results imply that, because of the unique characteristics of rural retail markets and the dominance of rural trade centers, these rural trade center cities are able to raise local tax rates and effectively export tax burden to nonresidents without significantly affecting their retail sales when the tax differential is not a large one.     

Simulation of insecticide influences on the population dynamics of the Colorado beetle

A weather-based simulation model of population development of Leptinotarsa decemlineata (Colorado beetle) has been extended to include the effects of insecticides. The dynamics of larvae (1st to 4th instar) and the resulting abundance of the adult summer generation has been simulated under the influence of insecticide applications. To describe the mortality caused by different insecticides on the stages of development of L. decemlineata, detailed experimental data are necessary. In this paper, preliminary experience to adapt the SIMLEP computer model to simulate insecticide action on L. decemlineata populations are published for the first time. These investigations aim at developing a more complete model which will be applicable to agricultural practice, not only to predict the dates of density maxima of the developmental stages of L. decemlineata, but also to estimate the need for and the required extent of insecticide applications, i.e. to guarantee optimum results from pesticide treatments.     

Changes in Cardiopulmonary Variables and Platelet Count During Anesthesia for Total Hip Replacement in Dogs

Changes in cardiopulmonary function and platelet count were determined in 22 dogs of various breeds that underwent total hip replacement with cemented femoral prostheses. In 11 dogs (group I) polymethylmethacrylate (PMMA) was inserted without venting the reamed and lavaged femoral canal. In a second group of 11 dogs (group II) a urethral catheter (ID: approximately 2.7 mm) was placed into the medullary cavity before the insertion of PMMA. The application of PMMA resulted in a decrease in end-tidal carbon dioxide tension (PETco₂) until 5 minutes after insertion of bone cement. Increases in arterial to end-tidal pCO₂ gradient [P(a-ET)co₂] and physiological dead space (V_D/V_T) were recorded between 2 minutes before and 5 minutes after insertion of PMMA in 12 dogs. A significant decrease in platelet count occurred in both groups of dogs. Decreases in arterial pO₂ (Pao₂), arterial/alveolar oxygen tension ratio (Pao₂/PAo₂), and percent O₂ saturation of hemoglobin in arterial blood (Sao₂) were not statistically significant. No significant differences could be detected between data obtained from both groups of dogs. An increase in femoral intramedullary pressure caused by the insertion of PMMA and subsequent pulmonary microembolism by medullary contents has been considered the most likely cause for changes in pulmonary function. The lack of statistically significant differences in cardiopulmonary variables and platelet count between the two groups of dogs could have been related to inefficient pressure reduction by the method used.     

The Medial Saphenous Fasciocutaneous Free Flap in Dogs

The purpose of this study was to identify the angiosome of the medial saphenous artery and vein and to evaluate the use of this cutaneous angiosome as a free skin flap in the dog. In phase 1 of this study, selective angiography of the medial saphenous artery performed in six canine cadavers showed that the skin covering the entire medial femorotibial area, the distal half of the caudal head of the sartorius muscle, and the gracilis muscle were perfused by the medial saphenous artery. In phase 2, a medial saphenous fasciocutaneous island flap was raised and sutured back to the skin edges of the donor wound in three dogs. One hundred percent survival of all of the flaps occurred. In phase 3, a medial saphenous fasciocutaneous microvascular free flap was transferred to a wound that was created over the dorsal metacarpal (n = 3) or metatarsal region (n = 3). The mean length ± SD of the medial saphenous vascular pedicle was 80 ± 13 mm (n = 5); the mean diameter ± SD of the medial saphenous artery was 2.8 ± 0.2 mm (n = 5) and the mean diameter ± SD of the medial saphenous vein was 4.2 ± 0.2 mm (n = 5). One hundred percent of all flaps survived (n = 6). Selective angiography of the distal cranial tibial artery (metatarsal wounds, n = 3) and the median artery (metacarpal wound, n = 3) was performed 3 weeks after surgery. All of the vascular anastomoses were patent and neovascularization of the wound beds was present. This free flap was found to be acceptable for cosmetic reconstruction of wounds located on the distal extremity.     

Oceanographic influences on the distribution of Baltic cod, Gadus morhua, during spawning in the Bornholm Basin of the Baltic Sea

The Baltic Sea is a stratified, semienclosed sea typified by a low-salinity surface layer and a deep saline layer of varying volume, salinity, temperature and oxygen concentration. The relationships between these oceanographic factors and the distribution of Baltic cod are presented, utilizing results from a survey carried out during the 1995 spawning period in the Bornholm Basin, at present the main spawning area of this stock. Cod distribution, abundance and population structure were estimated from hydroacoustic and trawl data and related to hydrographic parameters as well as to bottom depth. In the central basin, cod were aggregated in an intermediate layer about 15 m thick. This area of peak abundance was defined at its upper limit by the halocline and at the lower limit by oxygen content. The majority of individuals caught in the basin centre were in spawning or pre-spawning condition with a high proportion of males to females. On the basin slopes, aggregations of cod were found near the bottom. These individuals were mainly immature and maturing stages with an increasing proportion of females to males with size. Salinity and oxygen conditions were found to be the major factors influencing the vertical and horizontal distribution of adult cod. Abundance of immature cod was also positively related to decreasing bottom depths. The effect of temperature was minor. The observed size- and sex-dependent spawning aggregation patterns, in association with habitat volume and stock size, may influence cod catchability and thereby the assessment and exploitation patterns of this stock.     

Myoperitoneal Microvascular Free Flaps in Dogs: An Anatomical Study and a Clinical Case Report

The purpose of the anatomical study was to identify potential myoperitoneal microvascular free flaps, in dogs, that are based on a single artery and vein. The angiosomes of the right deep circumflex iliac artery and left phrenicoabdominal (cranial abdominal) artery were evaluated in six medium-sized canine cadavers. The right deep circumflex iliac artery and left phrenicoabdominal (cranial abdominal) artery were injected with a mixture of barium and latex (equal parts). The entire right and left transversus abdominis muscles were dissected from the abdominal wall and radiographed. The angiograms of the deep circumflex iliac artery showed poor arborization of the vessels within the transversus abdominis muscle in all six cadavers. The angiograms of the phrenicoabdominal (cranial abdominal) artery showed consistent filling of the vascular bed of the cranial half of the transversus abdominis muscle flap in all six dogs. The vascular pedicle lengths and the diameter of the arteries and veins of both the deep circumflex iliac and phrenicoabdominal (cranial abdominal) myoperitoneal free flaps were found to be acceptable for microvascular anastomosis. The deep circumflex iliac flap was unacceptable because of inadequate vascular perfusion. The cranial abdominal artery had a consistent, large branch that supplied the cranial half of the transversus abdominis muscle, thereby making a myoperitoneal flap supplied by this vessel a potentially useful free flap. An 8-year-old male, neutered, mixed-breed dog was evaluated for possible repair of a large defect of the hard palate. Previous operations, using local tissue flaps, had been unsuccessful. A myoperitoneal free flap, based on the right cranial abdominal artery, and consisting of the cranial portion of the transversus abdominis muscle, was used successfully to reconstruct the hard palate. Migrating epithelium from the edges of the wound covered the myoperitoneal flap by 10 weeks after surgery. Therefore, the cranial abdominal myoperitoneal free flap can be considered for reconstruction of intra-oral defects that cannot be repaired using conventional local flap techniques.     

RADIOGRAPHIC ASSESSMENT OF PULMONARY FLUID CLEARANCE IN HEALTHY NEONATAL FOALS

We characterized the kinetics of postnatal equine lung using sequential thoracic radiography. The aim was to establish the earliest time when normal foals have clear, radiolucent lung fields, and to characterize the pattern of this clearance. Both right-to-left and left-to-right thoracic radiographs were acquired in lateral recumbency at peak inspiration within the first 30 min after birth and thereafter at 1, 2, 3, 4, 6, 8, 12, 24, 48, and 72 h. Radiographs were interpreted by three observers. The overall assessment of radiographic lung clearance was followed by the evaluation of individual lung quadrants to document changes in pulmonary radiographic patterns over time. We concluded that thoracic images in a healthy foal older than 4 h should be characterized by clear lungfields and that after this time distinctions between physiologic and pathologic conditions can be made. The ventral lung cleared first, presumably due to the greater flexibility of the thoracic wall in this anatomic region.