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81.
Empirical relationships between land use/cover and estuarine condition in the Northeastern United States 总被引:1,自引:0,他引:1
Wilfrid Rodriguez Peter V. August Yeqiao Wang John F. Paul Arthur Gold Norman Rubinstein 《Landscape Ecology》2007,22(3):403-417
Land–water interactions were examined in three regions in the Virginian Biogeographic Province; the southern shore of Cape
Cod, Massachusetts; the Hudson/Raritan region of New York; and the eastern shore of the Delmarva (Delaware/Maryland/Virginia)
Peninsula. Cumulative distribution functions were used to evaluate similarity in environmental condition among estuaries.
Spatial-setting variables (location in a river, coastal lagoon, or in open waters) were associated with variation for some
measures of estuarine condition. Patterns of coastal urban and agriculture gradients were measured and their relationship
with indicators of estuarine condition was modeled statistically. When estuaries were pooled, the highest variation explained
by spatial-setting variables was found for dissolved oxygen (DO, R
2 = 0.44) and salinity (R
2 = 0.58), with DO decreasing in river locations and salinity decreasing with rainfall and sampling locations near rivers.
The explanatory power for the other indicator variables was low and varied from 6% to 27%. Rainfall explained some of the
variation (R
2 = 0.23) in total suspended solids. Moderate (0.4 < | r | < 0.7) to strong (| r | ≥ 0.7) linear associations were found between total urban area and measures of estuarine condition. Within regions, total
urban area was positively associated with Silver (r = 0.59), Cadmium (r = 0.65), and Mercury (r = 0.47) in Cape Cod, and inversely related to DO (r = −0.65) in the Hudson/Raritan region. No associations were found in the Delmarva Peninsula study area. Total area of agriculture
showed a moderate association with Arsenic in Cape Cod, but no other associations were found in the other two regions. Our
analyses show a measurable impact of urban land use on coastal ecosystem condition over large areas of the northeastern United
States. This pattern was most evident when many different landscapes were considered simultaneously. The relationship between
urban development and estuarine condition were weaker within the individual regions studied. The use of land use/cover models
for predicting estuarine condition is a challenging task that warrants enhancements in the type, quantity, and quality of
data to improve our ability to discern relationships between anthropogenic activities on land and the condition of coastal
environments. 相似文献
82.
In cereals, chromosome doubling of microspore-derived haploid plants is a critical step in producing doubled haploid plants.
This investigation was undertaken to study the effect of incorporation of colchicine in the induction medium for anther culture,
and the effect of colchicine on anther culture-derived plants of triticale grown under controlled greenhouse conditions. In
the latter case, chromosome doubling of adult sterile plants derived from anther culture of fourteen triticale populations
was attempted, where androgenetic plants with non-dehiscent anthers were cloned and subjected to the colchicine treatment,
and then grown with the aid of hydroponics. The hydroponic system provided optimal conditions for recovery of the affected
haploids from the toxic effects of colchicine treatment and all colchicine-treated plants survived. A topcross-F1 (TC1F1) population with timopheevii cytoplasm produced the highest percentage of plants with seed-set either due to chromosome doubling
by colchicine (98%) or spontaneous doubling of chromosome number (15%). Colchicine-treated anthers performed inferior than
control in both induction and regeneration phases. One of the key observation of this study was the reversal from reproductive
stage back to the vegetative stage which in turn enabled further cloning of haploid plants under hydroponic conditions once
they were identified as sterile. The one hundred percent survival rate of in vitro-derived plants, 100% survival rate of colchicine treated haploid plants and the high chromosome doubling success rate (X
= 82.3) observed in this study imply that a temperature-controlled greenhouse with an hydroponic system provides an efficient
environment for inducing chromosome doubling of haploid plants in cereals.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
83.
84.
PULMONARY MINERALIZATION IN FOUR DOGS WITH CUSHING'S SYNDROME 总被引:1,自引:0,他引:1
Clifford R. Berry DVM Norman Ackerman DVM Kevin Monce DVM 《Veterinary radiology & ultrasound》1994,35(1):10-16
The clinical and imaging features of four dogs with Cushing's syndrome and pulmonary mineralization are reviewed. Three dogs presented with a primary complaint of respiratory distress/dyspnea. Three dogs had pituitary dependent Cushing's syndrome, while the remaining one dog had iatrogenic Cushing's syndrome. Each dog had clinical features typical for Cushing's syndrome. Two of the dogs were euthanized due to progressive hypoxemia. In each dog, the serum calcium, phosphorous, blood urea nitrogen and creatinine were normal.
A generalized increase in unstructured interstitial pulmonary opacity with diffuse mineralization was noted on thoracic radiographs of all dogs. In one dog, an ill-defined nodular interstitial pattern of mineralization was present. Delayed bone phase scintigraphy using99m Technetium methylene diphosphonate documented generalized pulmonary uptake in two dogs. 99m Technetium labeled microaggregated albumin lung perfusion scans were normal in these two dogs. 99m Tc-MDP scintigraphy can provide useful information in diagnosing pulmonary mineralization in Cushingoid dogs. 相似文献
A generalized increase in unstructured interstitial pulmonary opacity with diffuse mineralization was noted on thoracic radiographs of all dogs. In one dog, an ill-defined nodular interstitial pattern of mineralization was present. Delayed bone phase scintigraphy using
85.
Norman C 《Science (New York, N.Y.)》1985,228(4704):1180
86.
87.
Norman C 《Science (New York, N.Y.)》1986,233(4767):934-935
88.
Nepalese porters routinely carry head-supported loads equal to 100 to 200% of their body weight (Mb) for many days up and down steep mountain footpaths at high altitudes. Previous studies have shown that African women carry head-supported loads of up to 60% of their Mb far more economically than army recruits carrying equivalent loads in backpacks. Here we show that Nepalese porters carry heavier loads even more economically than African women. Female Nepalese porters, for example, carry on average loads that are 10% of their Mb heavier than the maximum loads carried by the African women, yet do so at a 25% smaller metabolic cost. 相似文献
89.
Armstead I Donnison I Aubry S Harper J Hörtensteiner S James C Mani J Moffet M Ougham H Roberts L Thomas A Weeden N Thomas H King I 《Science (New York, N.Y.)》2007,315(5808):73
A key gene involved in plant senescence, mutations of which partially disable chlorophyll catabolism and confer stay-green leaf and cotyledon phenotypes, has been identified in Pisum sativum, Arabidopsis thaliana, and Festuca pratensis by using classical and molecular genetics and comparative genomics. A stay-green locus in F. pratensis is syntenically equivalent to a similar stay-green locus on rice chromosome 9. Functional testing in Arabidopsis of a homolog of the rice candidate gene revealed (i) senescence-associated gene expression and (ii) a stay-green phenotype after RNA interference silencing. Genetic mapping in pea demonstrated cosegregation with the yellow/green cotyledon polymorphism (I/i) first reported by Gregor Mendel in 1866. 相似文献
90.
Jonathan H. Foreman D.V.M. Stephen M. Reed D.V.M. Norman W. Rantanen D.V.M. M.S. Richard M. DeBowes D.V.M. M.S. Pamela C. Wagner D.V.M. M.S. 《Journal of Equine Veterinary Science》1983,3(5):154-164
Since the normal absorption of CSF occurs in the cerebral veins and venous sinuses, any obstruction to the normal flow and absorption of CSF will result in accumulation of CSF central to the site of obstruction. Such accumulation within the cranium is defined as hydrocephalus.A foal was presented with an enlarged and an abnormally-shaped skull, but with normal behavior. The filly's condition deteriorated. Radiographs showed a domeshaped cranial vault with compression of the frontal sinus region. Massive hydrocephalus with little normal cerebral tissue left was diagnosed with ultrasound.Surgery was attempted to relieve the pressure. Eventually the foal was euthanized. Post-mortem confirmed the radiographic and ultrasound diagnosis. Since there was a lack of demonstrable obstruction, the authors suspected the foal had suffered from the Arnold-Chiari syndrome. 相似文献