Ozenda,Paul, und Clauzade,Georges: Les Lichens. Etude biologique et flore illustrée. Verlag Masson & Cie., Paris, 1970. 801 Seiten (zweispaltig bedruckt), 676 Makroaufnahmen von Flechten und viele hundert Strichzeichnungen (beide zu 642 Abbildungen zusammengefaßt). Format 22,5 × 28 cm. Ganzleinen. Preis: NF 400,—     

H. Hertel 《植物养料与土壤学杂志》1971,129(2):148-149

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Association of brook trout and Oncorhynchus spp. with large wood jams in a Lake Superior tributary in a northern old‐growth watershed     

Arthur E. L. Morris  Lance R. Williams  P. Charles Goebel  Eugene C. Braig IV 《Ecology of Freshwater Fish》2012,21(4):597-608

Wood in streams functions as fish habitat, but relationships between fish abundance (or size) and large wood in streams are not consistent. One possible reason for variable relationships between fish and wood in streams is that the association of fish with wood habitat may depend on ecological context such as large‐scale geomorphology. We studied the relationship between salmonid assemblages and large wood jams (LWJ) in four settings that differed geomorphically at the scale of the stream corridor along a tributary to Lake Superior in old‐growth conifer–hardwood forest in northern Michigan. The focal fish species of this study were brook trout (Salvelinus fontinalis), which were wild in the stream. Relocation efforts for coaster brook trout (an adfluvial life history variant of brook trout) were ongoing in the study stream. We measured fish abundance and length in pairs of pools of similar size and substrate, but varying in the presence of LWJ; this allowed us to evaluate associations of fish simply with the presence of LWJ rather than with other channel or flow‐shaping functions of LWJ. The length of Oncorhynchus spp. and young introduced brook trout was not strongly correlated with LWJ presence; however, the presence of LWJ in pools was positively correlated with larger wild brook trout. We also found that the correspondence of LWJ with the abundance of salmonids appears to be moderated by the presence of alternative habitat in this relatively natural, old‐growth forest stream.  相似文献   

Soil nutrient supply and biomass production in a mixed forest on a skeleton‐rich soil and an adjacent beech forest     

Dirk Hlscher  Dietrich Hertel  Horst Koenies 《植物养料与土壤学杂志》2002,165(6):668-674

In the natural forest communities of Central Europe, beech (Fagus sylvatica L.) predominates in the tree layer over a wide range of soil conditions. An exception with respect to the dominance of beech are skeleton‐rich soils such as screes where up to 10 broad‐leaved trees co‐exist. In such a Tilia‐Fagus‐Fraxinus‐Acer‐Ulmus forest and an adjacent mono‐specific beech forest we compared (1) soil nutrient pools and net nitrogen mineralization rates, (2) leaf nutrient levels, and (3) leaf litter production and stem increment rates in order to evaluate the relationship between soil conditions and tree species composition. In the mixed forest only a small quantity of fine earth was present (35 g l^—1) which was distributed in patches between basalt stones; whereas a significantly higher (P < 0.05) soil quantity (182 g l^—1) was found in the beech forest. In the soil patches of the mixed forest C and N concentrations and also concentrations of exchangeable nutrients (K, Ca, Mg) were significantly higher than in the beech forest. Net N mineralization rates on soil dry weight basis in the mixed forest exceeded those in the beech forest by a factor of 2.6. Due to differences in fine earth and stone contents, the volume related soil K pool and the N mineralization rate were lower in the mixed forest (52 kg N ha^—1 yr^—1, 0—10 cm depth) than in the beech forest (105 kg N ha^—1 yr^—1). The leaf N and K concentrations of the beech trees did not differ significantly between the stands, which suggests that plant nutrition was not impaired. In the mixed forest leaf litter fall (11 %) and the increment rate of stem basal area (52 %) were lower than in the beech forest. Thus, compared with the adjacent beech forest, the mixed forest stand was characterized by a low volume of patchy distributed nutrient‐rich soil, a lower volume related K pool and N mineralization rate, and low rates of stem increment. Together with other factors such as water availability these patterns may contribute to an explanation of the diverse tree species composition on Central European screes.  相似文献   

Jejunal Intussusception: A Complication of Functional End-to-End Stapled Anastomoses in Two Ponies     

REBECCA L. FRANKENY VMD    DAVID A. WILSON DVM  MS  Diplomate ACVS    NAT T. MESSER IV DVM  Diplomate ABVP  CYNTHIA CAMPBELL-BEGGS DVM 《Veterinary surgery : VS》1995,24(6):515-517

Jejunojejunal intussusception occurred after jejunal resection and stapled functional end-to-end anastomosis in two pony mares. In both mares, the lead point of the intussusception was the stapled functional end-to-end (FEE) anastomosis. The stapled free ends of jejunum were oversewn with an inverting suture pattern. A possible explanation for development of the intussusception was the acute angle created in the intestine by the FEE anastomsis. This angulation may have impaired flow of ingesta causing motility changes that predisposed the site to intussusception. Because the oversewn blind intestinal ends acted as the lead point for formation of the intussusception, it may be inadvisable to oversew the stapled anastomotic ends.  相似文献   

Computational Comparison of Stand-Centered Versus Cover-Constraint Formulations     

Joseph H. Wilck IV  Steven D. Mills  Marc E. McDill 《Journal of Sustainable Forestry》2013,32(1):33-45

The area restriction model for harvest scheduling problems can be formulated using mixed integer programs. The three different formulation types are cluster packing, cell aggregation, and the assignment formulation. Within the cell aggregation subgroup there is an exact formulation, the cover constraint (CC) approach; and an inexact formulation, the stand-centered approach. The cover constraint formulation has significantly more constraints than the stand-centered formulation. A computational comparison between these two methods is completed using cutting planes and constraint combinations using the CPLEX solver package. The CC approach as cutting planes was superior based on solution time. If formulation time were included with solution time, then the CC approach remains superior. The maximum harvest area is a significant factor of solution time. In addition, the percentage of total cutting planes used to solve the problem was examined.  相似文献   

The influence of site factors on the composition and structure of semi-natural mixed-species stands of beech (Fagus sylvatica), silver fir (Abies alba) and Norway spruce (Picea abies) in the Upper Draganul Watershed of North-West Romania     

Abrudan  IV; Mather  RA 《Forestry》1999,72(2):87-94

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Long-term EKG in dogs: comparison between a computerized system and visual arrhythmia analysis]     

M Hertel  U Kersten  R Mischke  I Nolte 《Berliner und Münchener tier?rztliche Wochenschrift》1999,112(6-7):239-242

Based on results of holter ecg recordings taken from 38 dogs the computerized analyses system turned out as method not exactly valuing the frequency and sensitivity of arrhythmias. Despite there was a significant correlation between the computerized and visual arrhythmia analysis for ventricular respectively supraventricular premature beats, in individual cases there was an important aberration between the particular values.  相似文献   

Effect of pH on Structural Changes in Perch Hemoglobin that Can Alter Redox Stability and Heme Affinity     

Mark P. Richards  Roman Aranda IV  Cai He  George N. Phillips Jr. 《Journal Of Aquatic Food Product Technology》2013,22(4):416-423

pH can be manipulated to alter the oxidative stability of fish-based foods during storage. X-ray diffraction was used to investigate the ability of reduced pH to cause structural changes in fish hemoglobins that lead to enhanced oxidative degradation. Decreasing pH from 8.0 to 6.3 and 5.7 created a large channel for solvent entry into the heme crevice of perch hemoglobin beta chains. The proton-induced opening of this channel occurred between site CD3 and the heme-6-propionate. Solvent entry into the heme crevice can enhance metHb formation and hemin loss, processes that accelerate lipid oxidation. Reduced pH also decreased the distance between Ile at E11 in one of the alpha chains and the ligand above the heme iron atom. This sterically displaces O₂ and protonated O₂ which increases metHb formation. These studies demonstrate that pH reduction causes structural changes in perch hemoglobin which increase oxidative degradation of the heme pigment.  相似文献   

Laminitis and the Equine Metabolic Syndrome     

Philip J. Johnson  Charles E. Wiedmeyer  Alison LaCarrubba  V.K. Ganjam  Nat T. Messer IV 《Veterinary Clinics of North America: Equine Practice》2010

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Response of cocoa trees (<Emphasis Type="Italic">Theobroma cacao</Emphasis>) to a 13-month desiccation period in Sulawesi,Indonesia     

G. Moser  C. Leuschner  D. Hertel  D. Hölscher  M. Köhler  D. Leitner  B. Michalzik  E. Prihastanti  S. Tjitrosemito  L. Schwendenmann 《Agroforestry Systems》2010,79(2):171-187

In South-east Asia, ENSO-related droughts represent irregularly occurring hazards for agroforestry systems containing cocoa which are predicted to increase in severity with expected climate warming. To characterize the drought response of mature cocoa trees, we conducted the Sulawesi Throughfall Displacement Experiment in a shaded (Gliricidia sepium) cocoa agroforestry system in Central Sulawesi, Indonesia. Three large sub-canopy roofs were installed to reduce throughfall by about 80% over a 13-month period to test the hypotheses that (i) cocoa trees are sensitive to drought due to their shallow fine root system, and (ii) bean yield is more sensitive to drought than leaf or stem growth. As 83% of fine root (diameter <2 mm) and 86% of coarse root biomass (>2 mm) was located in the upper 40 cm of the soil, the cocoa trees examined had a very shallow root system. Cocoa and Gliricidia differed in their vertical rooting patterns, thereby reducing competition for water. Despite being exposed for several months to soil water contents close to the conventional wilting point, cocoa trees showed no significant decreases in leaf biomass, stem and branch wood production or fine root biomass. Possible causes are active osmotic adjustment in roots, mitigation of drought stress by shading from Gliricidia or other factors. By contrast, production of cocoa beans was significantly reduced in the roof plots, supporting reports of substantial reductions in bean yields during ENSO-related drought events in the region. We conclude that cocoa possesses traits related to drought tolerance which enable it to maintain biomass production during extended dry periods, whereas bean yield appears to be particularly drought sensitive.  相似文献