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  • 1
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 64 (1994), S. 3389-3391 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Submicron-period gratings have been formed in polyethylene terephthalate and polyimide films using a KrF laser irradiated, zero suppressed, phase mask with a period d=533 nm. The imprinted grating has a dominant period of d rather than d/2, a result which is shown to be due to recording the pattern by a threshold surface ablation process.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 17 (1994), S. 0 
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Using two ecotypes of Stellaria longipes an alpine form with low plasticity and a prairie form with high plasticity, we investigated whether ethylene was involved in the response to wind stress and might be important in controlling plasticity of stem elongation. Stem growth inhibition was positively correlated with concentration of ethephon application and elevation in ambient ethylene in alpine ecotypes, whereas stem growth in prairie plants was stimulated by low ethephon concentrations. When treated with high AVG, the effects were reversed: alpine plant growth was promoted and prairie plant growth was inhibited. Prairie plants exhibited a daily rhythm in ethylene evolution which increased and peaked at 1500 h, and which was absent in alpine plants. Ethylene evolution did not change significantly during the first 2 weeks of growth in alpine plants, whereas ethylene in prairie plants increased significantly during periods of rapid stem elongation. Wind treatment inhibited growth in both ecotypes, but only alpine plants showed a recovery of growth to control levels when wind stressed plants were pretreated with STS. In addition, only alpine plants showed an increase in ethylene evolution in response to wind simulation, whereas prairie plant ethylene evolution did not deviate from rhythms observed in unstressed plants. We concluded that ethylene dwarfs stems in alpine S. longipes in response to wind stress. However, low levels of ethylene may stimulate growth in prairie ecotypes and act independently of wind stress intensity. The contrasting ability to synthesize and respond to ethylene can account for part of the difference in plasticity documented between the two ecotypes.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 13 (1990), S. 0 
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract. Gravistimulation was investigated as a potential and unwanted component in the interpretation of physiological investigations on plants. Using both seedlings and mature sunflower plants, two situations are described where gravistimulation contributes significantly to the outcome of an experiment not initially designed to include this parameter. The number of adventitious roots formed in derooted seedings decreased when the tops of the plants were allowed to bend over under their own weight, and the effect correlated positively with the rate of ethylene production by non-vertical stems. In droughted mature plants, and increase in leaf and stem ethylene caused by water stress was supplemented by additional ethylene produced in the lower halves of stems. Drought had caused these stem tissues to wilt, become gravistimulated, and thus produce more ethylene. Other situations in which gravistimulated ethylene production and its physiological consequences are likely to be complicating factors in experiments are discussed. It is concluded that procedures that unnecessarily place experimental material in non-vertical orientations should be avoided.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 30 (1974), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Kharkov 22 M.C. winter wheat was grown continuously from seed under four temperature regimens; 2°C; 2°C then transferred to 20°C; 6°C, and 20°C. Plants were harvested at the 4-leaf stage (except the 2°C plants which were harvested at the 3-leaf stage) and the levels of endogenous gibberellins (GAs) were measured and their cold hardiness determined. The GA content of 20°C and the 6°C seedlings were about equal and greater (by 4- to 30-fold) than the GA content of 2°C seedlings that had been transferred to 20°C (i.e. vernalized). The GA content of the 2°C seedlings was least of all, being 28- to 320-fold less than the 20°C seedlings. At harvest the leaves of the 20°C seedlings were somewhat larger than those of the seedlings grown at 2°C and transferred to 20°C. The leaves of the 6°C seedlings were very much smaller and the leaves of the 2°C seedlings were smallest of all.It is concluded that while GAs may play a role in controlling leaf size and level of cold hardiness of wheat, they are not the most important factor.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Planta 111 (1973), S. 261-266 
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Treatment of waterlogged tomato plants with benzyladenine relieved most of the symptoms of flooding injury. The effects of benzyladenine included maintenance of chlorophyll levels, reduced epinastic curvature of petioles, absence of adventitious roots, and stem growth greater than that of waterlogged control plants.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Field and experimental studies were conducted to determine the incidence of chela loss and its effect on mating success in a population of the shore crab Carcinus maenas (Linnaeus, 1758) inhabiting the Menai Straits, North Wales. The study was performed between 1989 and 1993. Male crabs showed a higher degree of chela loss (12.5%) than females (7.9%). In males, frequencies ranged from ∼10% at sizes 50 mm CW (carapace width) up to ∼30% in the largest crabs of 70 to 80 mm CW. The percentage of females with missing chelae appears to be unrelated to size. The most common type of chela loss in the population studied was of a missing crusher chela of right-handed crabs. Red crabs, which are assumed to be in prolonged intermoult, had a much higher degree of chela loss (20.5%) than the green, early intermoult crabs (9.7%). The proportion of red crabs with chela losses increased with size, possibly reflecting an increase in intermoult duration with size. In green crabs, there was no such increase. The proportion of male crabs with missing chelae found in mating pairs in the field was much lower than that found in the adult unpaired population, suggesting that the loss of a chela constitutes a handicap to a male crab when trying to mate. Also, by studying the relative frequencies of different categories of chela loss, it is suggested that the loss of a crusher chela exerts a more deleterious effect than the loss of a cutter. Experiments were performed in the laboratory where pairs in pre-copula were confronted with an additional single male in various combinations of sizes and patten of chela loss. These showed that the loss of a chela constitutes a handicap for a male crab when either competing for or defending a paired pre-moult female. This handicap was estimated to be equivalent to a reduction in size of 7 to 8 mm CW relative to the size of the competitor.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1433-2965
    Keywords: Body weight ; Non-attendance ; Osteoporosis ; Response bias ; Risk factors ; Screening
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Poor compliance may be detrimental to the effectiveness of a screening programme if those at greatest risk of the disease do not attend. Therefore we undertook a study to test whether non-attenders to a screening programme for low bone density, a risk factor for osteoporosis, were at a differential risk of low bone density compared with attenders. Seven hundred and eighty-nine women aged 45–49 years living within 32 km of Aberdeen were selected at random from the Community Health Index and invited to attend for screening for low bone density as a risk of factor for osteoporosis. Attenders and non-attenders were surveyed regarding their risk factors for osteoporosis. Non-attenders were significantly heavier than attenders. In addition, 6 non-attenders who subsequently chose to attend had significantly higher body weight and bone mineral density, at Ward's triangle, than initial attenders. Non-attenders to a screening service for bone density may be at lower risk of developing osteoporosis. Non-attendance, therefore, would not be detrimental to the cost-effectiveness of a screening service for bone density. However, this study indicates there is a potential for response bias in studies of bone density and osteoporosis.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-0827
    Keywords: Osteoporosis ; Ultrasound ; Hip fractures ; Bone density ; DXA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract There is considerable interest in predicting risk of hip fracture in order to allow targeting of preventive care. This study aimed to determine which of two methods best discriminates a hip fracture population from controls. Fifty women with fractured neck of femur, and 50 control subjects were scanned using dual energy X-ray absorptiometry (DXA) of the spine and hip and broadband ultrasound attenuation (BUA) of the os calcis. Significant differences between the two populations could be found for both DXA and BUA, with BUA showing the largest percentage difference (27%). The mean z-scores showed that BUA had the lowest, with the exception of DXA trochanter. However, no significant difference between BUA and DXA trochanter Z-scores was found. A receiver operator characteristic (ROC) analysis showed that BUA has a superior sensitivity and specificity compared with DXA measurements, with DXA of the hip being better than the spine. This retrospective study shows that BUA is a better discriminator of hip fracture than DXA lumbar spine of DXA hip, which may have important implications for predicting those at risk of future hip fracture.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 12 (1973), S. 101-112 
    ISSN: 1432-0827
    Keywords: Ageing ; Osteoporosis ; Bone ; Muscle ; Fat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des mesures radiologiques de la masse minérale osseuse de la partie proximale du radius et l'épaisseur du muscle et du tissu graisseux sous-cutané de l'avant-bras ont été relevées chez l'homme et la femme adultes normaux. La masse minérale osseuse ne montre pas de modification significative jusqu'à 60 ans chez l'homme et 50 ans chez la femme, puis on observe une chute. L'épaisseur musculaire décroit, chez l'homme, à partir de 30 ans, alors que chez la femme on n'observe aucune modification significative avant 60 ans. Les corrélations entre ces variables diffèrent selon le sexe. Alors que la masse minérale et l'épaisseur musculaire varient positivement chez l'homme en fonction de l'âge, il n'y a pas de rapport significatif chez la femme, après 60 ans. Cependant, chez ces dernières, la masse osseuse et le tissu graisseux sous-cutané sont en corrélation nette après 60 ans, bien qu'aucun rapport significatif ne soit noté chez l'homme quel que soit le groupe d'âge. Chez des sujets ostéoporotiques, la masse minérale osseuse et l'épaisseur musculaire sont plus faibles chez les hommes par rapport à des sujets normaux du même âge. Chez des femmes ostéoporotiques, cependant, bien que la masse minérale osseuse et le tissu graisseux sous-cutané soient inférieures par rapport à des sujets normaux, l'épaisseur du muscle n'est pas modifiée.
    Abstract: Zusammenfassung Es wurden bei gesunden erwachsenen Männern und Frauen radiologische Messungen der Knochenmineralmasse im proximalen Radius, der Dicke des Muskels und des subkutanen Fettes des Vorderarmes durch die ganze Altersspanne durchgeführt. Die Knochenmineralmasse zeigte keine signifikante Veränderung bis zum 60. Altersjahr bei den Männern und bis zum 50. Altersjahr bei den Frauen; dann jedoch sank sie ab. Die Muskeldicke nahm bei den Männern über 30 Jahren ab, bei den Frauen konnte jedoch eine signifikante Abnahme erst ab 60 Jahren festgestellt werden. Die Korrelation zwischen diesen beiden Werten war bei Männern und Frauen ebenfalls verschieden. Während bei den Männern Knochenmineralmasse und Muskeldicke in jedem Alter meistens eine positive Korrelation zeigte, konnte bei den Frauen nach dem 60. Altersjahr keine signifikante Korrelation gefunden werden. Bei den Frauen zeigten hingegen Knochenmasse und subkutanes Fett eine deutliche Korrelation in der Gruppe nach dem 60. Altersjahr, während bei den Männern in keiner Altersgruppe eine signifikante Korrelation gefunden werden konnte. In einer osteoporotischen Gruppe waren Knochenmineralmasse und Muskeldicke niedriger bei Männern, verglichen mit Kontrollen bei Gesunden desselben Alters. Bei weiblichen osteoporotischen Patienten hingegen zeigte die Muskeldicke keinen Unterschied, während Knochenmineralmasse und subkutanes Fett niedriger waren als bei Gesunden.
    Notes: Abstract Radiologic measurements of bone mineral mass in the proximal radius, muscle width and thickness of the subcutaneous fat of the forearm were studied in normal men and women throughout the adult age range. Bone mineral mass showed no significant change to age 60 in men and age 50 in women, but fell thereafter. Muscle width declined from age 30 in the male population, though no significant reduction was found in women before age 60. The correlations between these variables also differed between males and females. While bone mineral mass and muscle width tended, in males, to be positively correlated at all ages, in females no significant correlation was found after age 60. In females, however, bone mass and subcutaneous fat were distinctly correlated in the over 60 age group, though no significant correlation was found in males in any age group. In an osteoporotic group, bone mineral mass and muscle width were lower in male patients than in normals of similar age. In female osteoporotic patients, however, while bone mineral mass and subcutaneous fat were less than in normals, muscle width showed no difference.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 47 (1991), S. 759-761 
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
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