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  • 1
    ISSN: 0931-1890
    Keywords: Key words Wind ; Acidic mist ; Foliar injury ; Cuticular integrity ; Gas exchange
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  This research demonstrates that a leaf’s response to acid mist is dependent on the integrity of the leaf cuticle and that significant differences in the structural and physiological disturbances in leaves can be attributable to different types of wind action. Betula pubescens Ehrh. plants were located at adjacent, but contrasting, sites to create different wind treatments: (i) direct wind action, (ii) indirect wind action and (iii) shelter from wind action (control). In combination with the wind treatments, acidic (pHs 5 and 3) or neutral (pH 7) mists were applied weekly. Wind action significantly increased visible leaf injury, microscopic cuticular lesions and cuticular conductance (g c ), but reduced photosynthetic rate (P N ) and stomatal conductance (g s ) compared to shelter. Wind action combined with acid mist was more injurious than wind action alone, but leaves sheltered from wind action were highly resistant to the damaging effects of acid mist. Direct wind action combined with pH 3 mist resulted in the highest values of g c and the greatest number of cuticular lesions. By contrast, indirect wind action combined with pH 3 mist induced most visible injury, but relatively low values of g c and few microscopic cuticular lesions. Acid mist reduced P N only when leaves had been damaged by wind action. Higher values of g c were associated both with increases in the area of visible leaf injury and with the number of cuticular lesions. Compensatory increase in P N of healthy tissue was evident in leaves exposed to combinations of wind action and acid mist.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1438-1168
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Zusammenfassung Ca-reiche Pyroxene von basischen und sauren Gesteinen der Cameroon Volcanic Line (Westafrika): Kristallchemie und petrologische Beziehungen C2/c Pyroxenphänokristalle aus basischen Gesteinen (Basanit–Trachyphonolith-Suite und Alkalibasalte) und differenzierte CIPW Ne- und Q-normative Trachyte und Rhyolithe, die im kontinentalen Sektor der Cameroon Volcanic Line auftreten, wurden mittels Einkristall-Röntgendiffraktion, ergänzt durch Elektronenmikrosonden-Analyse, untersucht. Diese Technik ermöglicht genaue Angaben zur Besetzung der Gitterpositionen und der geometrischen Variationen. Der untersuchte Klinopyroxen ist die einzige kristallisierende Ca-reiche Liquidusphase, sowohl in den basischen als auch in den differenzierten Vulkaniten. Klinopyroxene aus alkalischen Gesteinen sind durch große VT, als Folge von niedrigem Si(T) und von Si-AlVI Substitution, charakterisiert, was wiederum hohe R3+(AlVI + Fe3+ + Cr3+ + Ti4+) in der M1 Position erforderlich macht. Klinopyroxene aus differenzierten sauren Vulkaniten haben ein großes VM1. Dies steht mit hohen Fe2+ (M1) Gehalten in Beziehung, da Klinopyroxen aus MgO-armen (〈 0.5 Gew.%) Schmelzen bei relativ niedrigem fO2 (QFM Buffer) auskristallisierte. Die hohen Fe2+-Gehalte in M1 verursachen eine Verlängerung der 〈M1-O〉 Abstände, was wiederum eine Verkürzung der T-O1 und T-O2 Abstände (i.e. hohes Si) erforderlich macht, ungeachtet der magmatischen Affinität des Klinopyroxens in SiO2-untersättigten oder -übersättigten Bedingungen. Daher haben Klinopyroxene aus sauren Gesteinen ähnliche (Ca + Na)- Gehalte wie jene aus basischen; aber ihr 〈M2-O3〉 ist, als Folge der 〈T-O3〉 Verkürzung, relativ länger. Daraus folgt, daß Klinopyroxene, die aus silikatischen Schmelzen auskristallisieren eine relativ große Zunahme in VM2 zeigen, die aber nicht mit einer Zunahme von (Ca + Na) in Beziehung steht. Die β-ΔM2 (Verzerrungsparameter) Beziehung zeigt, daß die basischen Magmen, die Stammagmen der Q-normativen Gesteine, leicht bis mäßig alkalische Basalte waren und nicht SiO2-untersättigte oder -übersättigte. Jene der Trachyphonolithe und Ne-Trachyte waren deutlicher SiO2-untersättigt (z.B. die basanitischen Magmen). Die Beziehungen von Vcell-VM1 bestätigen, daß die Klinopyroxenphänokristalle in der Kruste bei relativ niedrigen Drucken (ca. 1–5 kbar) kristallisierten.
    Notes: Summary C2/c pyroxene (Cpx) phenocrysts from basic rocks (basanite-trachyphonolite suite and alkali basalts) and differentiated CIPW Ne- and Q-normative trachytes and rhyolites occurring in the continental sector of the Cameroon Volcanic Line were investigated by single-crystal X-ray diffraction combined with electron probe microanalysis. This technique provides accurate data on site occupancy and geometric variations. The investigated Cpx is the only liquidus Ca-rich crystallizing phase from both basic and differentiated volcanics. Cpx from basic alkaline rocks are characterized by large VT owing to their low Si(T), which requires high R3+ (AlVI + Fe3+ + Cr3+ + Ti4+) in M1 site, due to Si-AlIV substitution. High Ca content allows the appropriate netcharge for the overbonded O3 oxygens. Cpx from differentiated silicic volcanics have large VM1 related to high Fe2+ (M1), since Cpx crystallized from MgO-poor (〈 0.5 wt%) melts at relatively low fO2 (QFM buffer). The high Fe2+ (M1) causes lengthening of 〈M1-O〉, which requires shortening of T-O1 and T-O2 (i.e. high Si), irrespective of the magmatic affinity of the Cpx in SiO2-undersaturated or oversaturated conditions. Therefore, Cpx from silicic rocks have similar (Ca + Na) contents to those formed from basic rocks, but their 〈M2-O3〉 is relatively longer, owing to the shortening of 〈T-O3〉. It follows that Cpx crystallizing from silicic melts show a relatively large VM2 increase, which is not related to an increase in (Ca + Na). The β-ΔM2 (distortion parameter) relationship of Cpx indicates that the basic magmas parental to Q-normative rocks were slightly to moderately alkaline basalts and not SiO2-undersaturated or oversaturated, while those from trachyphonolite and Ne-trachyte were distinctly more SiO2-undersaturated (e.g. basanitic magmas). Vcell–VM1 relationships confirmed that the investigated Cpx phenocrysts crystallized in the crust at relatively low pressure (ca. 1–5 kbar).
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Pediatric radiology 23 (1993), S. 202-203 
    ISSN: 1432-1998
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A case of vein of Galen aneurysm, studied with a fast gradient refocusing pulse MRI sequence, is presented. Fast MRI sequences allowed the acquisition of additional hemodynamic information that was not available with either routine MRI or angiography.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1998
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Cranial CT and/or MRI imaging of 8 patients with mucopolysaccharidosis (MPS) was retrospectively evaluated. Two patients had MPS IH, 1 had MPS IS, 1 had MPS IVA and 4 had MPS IV. CT and MRI showed thickening of dura mater at the cranio-cervical junction, causing narrowing of the subarachnoid space, in all the patients examined. Spinal cord compression was detected in 4 patients. Other findings were: white matter alterations, mild to severe hydrocephalus, skull dysplasia and odontoid dysplasia. White matter alterations were evident as large areas and as multiple dispersed spots of prolonged T1 and T2 value. Reduced gray/white matter contrast was demonstrated on T2-weighted MRI images. It is important to examine the cranio-cervical junction carefully for thickening of dura mater in all patients with mucopolysaccharidosis examined by CT or MRI, because of the generally progressive clinical course of MPS. In patients with symptomatic cord compression, surgical intervention should be considered.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1998
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We report on a 8-month-old boy with AIDS, born of an asymptomatic mother with positive HTLV-III serology. He was hospitalized in the Intensive Care Unit because of anemia, fever and hepatosplenomegaly. Chest X-ray showed pneumonia and subsequent blood cultures were positive for Candida albicans. After 3 days of Amphotericine B treatment, the patient was transferred to Infectious Disease Department. After 30 days of hospitalization, the patient developed a rapid neurological impairment evolving into coma. CT scan showed a round, ringshaped low density lesion with hypershaped low density lesion with hyper-dense and enhancing haemorragic centre in the left basal ganglia and a smaller hypodense lesion on the right. There was also evidence of cortical atrophy and mild ventricular dilatation. Such lesions are more commonly described in children with AIDS and congenital cytomegalic inclusion virus (CMV) encephalitis. In this case toxoplasma cysts were shown microscopically reinforcing the contention that in patients with AIDS, toxoplasma gondii infection may occur with atypical manifestation.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-1998
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In this study of 14 patients with anorectal anomalies CT and MRI were employed for preoperative assessment. The use of a pressure enhanced water soluble enema via the colostomy proved to be an extremely efficient method for showing a fistula. MRI studies were enhanced by the use of vaseline oil and in one case this technique was used prior to surgery to provide important information by injecting through a perineal fistula. CT and axial MRI proved to be more valuable than sagittal MRI which is only useful for the length of the atretic segment. The authors consider that a combined approach using pressure enhanced water soluble enema and MRI will provide the most valuable preoperative information to plan a successful operative approach and enable an accurate prognostic evaluation of continence in these difficult and complex patients.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-1998
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Intraabdominal calcifications are an unusual radiographic finding in the newborn and can easily be misinterpreted as meconium peritonitis. The authors refer to a patient with anorectal malformation (ARM), intraluminal calcifications and other anomalies. Careful differentiation of the type of intraabdominal calcifications can suggest the possibility of other initially unsuspected anomalies.
    Type of Medium: Electronic Resource
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