Search Results - (Author, Cooperation:Küppers)

Müller-Küppers, Manfred

Unknown

288 S. : Ill.

3466301084

German

Dress, Andreas; Hendrichs, H.; Küppers, Günter

Unknown

234 S.

3-492-03077-7

Küppers, Bernd-Olaf

Unknown

283 S.

3492107435

Küppers-Hellmann, Barbara; Hemker, Maria; Eissing, Günter

Unknown

114 S.

3544601761

Krohn, Wolfgang; Küppers, Günter

Unknown

414 S.

1. Aufl.

3-518-28584-X

1365-3040

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Abstract The lignotuberous mallee Eucalyptus behriana F. Muell, had much lower predawn leaf water potentials (not higher than – 1.2MPa) than other eucalypts (as high as – 0.2MPa), even after extended rain. This led to the expectation that the lignotuber of E. behriana might have specific hydraulic characteristics. Keeping the soil around partially defoliated mallces for several days underwater did not raise the water status above the maximum leaf water potential observed under natural conditions. Digging a plant out and placing its roots in water after removal of the soil rapidly increased the water status to a level consistant with other eucalypts. This indicated that the major impedance to water uptake was a component of the soil rather than in the roots or in the lignotuber.Some of the individual mallces had only two major stems or branches. One stem or branch was kept covered throughout the experiments to prevent transpiration. The other stem was subjected to a variety of different conditions in order to modify water loss from it. The transpiring branch affected the water status of the non-transpiring plant parts. Hydraulic resistances in the shoot and root/lignotuber were determined from differences in the leaf water potential of covered and uncovered branches, at high water flow rates through the plant. Resistances in branches, including the liquid phase component of the leaf, were significantly larger than in root or lignotuber.The total plant hydraulic resistance of E. behriana was similar to that of other eucalypts, such as E. pauciflora Sieb. ex Spreng. or E. delegatensis R. T. Bak., even though its growth form was different and its natural leaf water potentials were much lower. An osmotic adjustment at the leaf level was observed in the mallee, keeping its bulk leaf turgor in the same range as compared to the other eucalypt species.

Electronic Resource

1365-3040

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Abstract. Seedlings of Pinus radiata D. Don were grown in growth chambers for 22 weeks with two levels of phosphorus, under either well-watered or water-stressed conditions at CO2 concentrations of either 330 or 660mm3 dm−3. Plant growth, water use efficiency and conductance were measured and the relationship between these and needle photosynthetic capacity, water use efficiency and conductance was determined by gas exchange at week 22. Phosphorus deficiency decreased growth and foliar surface area at both CO2concentrations; however, it only reduced the maximum photosynthetic rates of the needles at 660 mm3 CO2 dm−3 (plants grown and measured at the same CO2 concentration). Water stress reduced growth and foliar surface area at both CO2 concentrations. Increases in needle photosynthetic rates appeared to be partly responsible for the increased growth at high CO2 where phosphorus was adequate. This effect was amplified by accompanying increases in needle production. Phosphorus deficiency inhibited these responses because it severely impaired needle photosynthetic function. The relative increase in growth in response to high CO2 was higher in the periodically water-stressed plants. This was not due to the maintenance of cell volume during drought. Plant water use efficiency was increased by CO2 enrichment due to an increase in dry weight rather than a decrease in shoot conductance and, therefore, transpirational water loss. Changes in needle conductance and water use efficiency in response to high CO2 were generally in the same direction as those at the whole plant level. If the atmospheric CO2 level reaches the predicted concentration of 660 mm3 dm−3 by the end of next Century, then the growth of P. radiata will only be increased in areas where phosphorus nutrition is adequate. Growth will be increased in drought-affected regions but total water use is unlikely to be reduced.

Electronic Resource

1365-3040

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Abstract A field portable system is described which measures the response of gas exchange of one leaf to changes in environmental parameters under controlled conditions, and which simultaneously measures the gas exchange of another leaf as the climatic parameters vary naturally. The system consists of two independently operating cuvettes. It enables detailed studies of photosynthesis and stomata/transpiration of leaves attached to the plant in their natural position. It provides control of temperature, humidity, CO2 and oxygen concentration (or, alternatively, of other gases) as well as of light. Infrared gas analyzers for CO2 and H2O are used which allow similar time constants for the measurement of the two gases.Examples of a diurnal course of gas exchange of a leaf in its natural exposition and of experiments with steady-state responses of gas exchange are presented. In Eucalyptus pauciflora Sieb. ex Spreng. ssp. pauciflora, a set of response curves of CO, assimilation (A) to CO2, as measured at various leaf temperatures and light levels, shows carboxylation efficiency to be light saturated at the lower photon irradiances the lower the leaf temperature is. Carboxylation efficiency is maximal at 25°C. At ambient CO, partial pressure stomata open in a way that CO2 assimilation occurs at a rate found within the curvature region of the CO2 response function of A. The light-independent CO2 compensation point as a function of temperature is presented.Applying a combined heat/low humidity pulse (15 or 60 min) on leaves of Eucalyptus behriana F. Muell. or Pinus radiata R. Don, respectively, leads to a lower level of intercellular carbon dioxide partial pressure (Ci) during the decline in A and leaf conductance to water vapour (g). A lower Ci level is maintained during recovery of A and g, A almost reaching the pre-pulse level but not g. The existence of an after-effect indicates that the response to the combined high temperature/low humidity pulse is a multi-step process.

Electronic Resource

1437-1596

Springer Online Journal Archives 1860-2000

Medicine

Law

Electronic Resource

1432-2285

Amyema miquelii ; Daily carbon balance ; Daily water balance ; Eucalyptus behriana ; Photosynthesis ; Water-use efficiency ; Xylem pressure ; Heterotrophy

Springer Online Journal Archives 1860-2000

Biology

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Summary Leaf gas exchange and xylem pressures of the xylem-tapping mistletoe, Amyema miquelii (Lehm. ex Miq.) Tiegh., and its host, Eucalyptus behriana F. Muell., both growing under permanently low plant water status, are studied under controlled and naturally fluctuating field conditions. Stomata of both plants regulate transpiration with respect to light and air humidity, but leaf conductances and total daily transpiration are up to 7.3 times higher in the host. Despite this, water-use efficiency in the mistletoe is lower than in the host. In the light of the mistletoe's low transpiration rates observed in spring, a commonly accepted pattern of higher water losses from parasites is likely to be inconsistent over a season. The role of partial parasitic carbon heterotrophy is discussed.

Electronic Resource

1432-2285

Amyema miquelii ; Eucalyptus behriana ; Leaf conductance ; Porometry ; Xylem pressure

Springer Online Journal Archives 1860-2000

Biology

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Summary Over several days at permanently low plant water status in the field, where predawn xylem pressures (Ψ) were never higher (less negative) than −1.2 MPa even after extended rain, leaf conductances (g) and transpiration rates of host trees, Eucalyptus behriana F. Muell., were higher than in mistletoes, Amyema miquelii (Lehm. ex Miq.) Tiegh., which contrasts with most studies known from the literature. Mistletoes influenced Ψ but not g of host leaves distal to the haustorium. Releasing xylem tension by cutting a host stem under water raised Ψ from about −3.5 MPa to about −0.5 MPa in both plants indicating that factors in the root zone were responsible for the low Ψ in the host. In all cases, with a freely transpiring or non-transpiring parasite at low and at artificially raised Ψ, mistletoe xylem pressure was lower than that of the host. Possible reasons are discussed.

Electronic Resource

1432-1939

Photosynthetic capacity ; Stomata ; Carboxylation efficiency ; Eucalyptus ; Acacia

Springer Online Journal Archives 1860-2000

Biology

Summary The rate of CO2 assimilation at light saturation and an intercellular CO2 concentration of 350 μl l-1 (photosynthetic capacity), measured in leaves of Eucalyptus pauciflora, E. behriana, E. delegatensis and Acacia melanoxylon, declined over the course of cloudless days under naturally varying environmental conditions as well as under constant optimal conditions for high CO2 uptake. Since the capacity did not recover during the light period, it was different from the “midday depression” of gas exchange. The change appeared to be caused neither by the diurnal variation of total leaf water potential, by photoinhibition of redox-reaction centres in photosystems nor by changes in the intrinsic properties of Ribulose-bisphosphate carboxylase-oxygenase. The decline was more pronounced in winter than in summer. It was related to the duration of illumination or the cumulative carbon gain. It was reversible in the following dark phase, and it did not occur on changeable days with short peaks of high light. Despite the decline in photosynthetic capacity, the initial slope of the CO2 response of net photosynthesis, as obtained at low intercellular CO2 concentrations, remained constant during the day, but declined at night when photosynthetic capacity recovered. In all cases stomatal conductance varied in parallel with photosynthetic capacity. The relevance of changes in photosynthetic capacity for the intercellular CO2 concentration is discussed.

Electronic Resource

1432-1939

CO2 assimilation ; stomatal responses ; soil drying rate ; cowpea

Springer Online Journal Archives 1860-2000

Biology

Summary Well watered plants of Vigna unguiculata (L.) Walp cv. California Blackeye No. 5 had maximum photosynthetic rates of 16 μmol m-2 s-1 (at ambient CO2 concentration and environmental parameters optimal for high CO2 uptake). Leaf conductance declined with increasing water vapour concentration difference between leaf and air (Δw), but it increased with increasing leaf temperature at a constant small Δw. When light was varied, CO2 assimilation and leaf conductance were correlated linearly. We tested the hypothesis that g was controlled by photosynthesis via intercellular CO2 concentration (c i). No unique relationship between (1) c i, (2) the difference between ambient CO2 concentration (c a) and c i, namely c a-c i, or (3) the c i/c a ratio and g was found. g and A appeared to respond to environmental factors fairly independently of each other. The effects of different rates of soil drying on leaf gas exchange were studied. At unchanged air humidity, different rates of soil drying were produced by using (a) different soils, (b) different irrigation schemes and (c) different soil volumes per plant. Although the soil dried to wilting point the relative leaf water content was little affected. Different soil drying rates always resulted in the same response of photosynthetic capacity (A max) and corresponding leaf conductance (g(Amax)) when plotted against percent relative plant-extractable soil water content (W e %) but the relationship with relative soil water content (W e ) was less clear. Above a range of W e of 15%–25%, A max and g(Amax) were both high and responded little to decreasing W e . As soon as W e fell below this range, A max and g(Amax) declined. The data suggest root-to-leaf communication not mediated via relative leaf water content. However, g(Amax) was initially more affected than A max.

Electronic Resource

2018-07-27

Es wird über Erfahrungen berichtet, die mit einem gruppentherapeutischen Programm gesammelt wurden, das für bosnische Kinder, die mit ihren Eltern nach Deutschland geflüchtet waren und die in Jugoslawien den Krieg am eigenen Leib erfahren hatten, gesammelt wurden. Diese Erlebnisse führen dazu, dass solche Kinder unter Alpträumen, Angstgefühlen, Einsamkeit, Verwirrung und Niedergeschlagenheit leiden und mit Aggressionen gegen sich und andere reagieren. Das Programm wurde erstmals im Sommer und Herbst 1995 eingesetzt und evaluiert. Das Programm und die Ergebnisse der Evaluation werden beschrieben.

Psychology ; Psychologie ; Childhood ; Kindesalter ; 3313 Group & Family Therapy ; 3215 Neuroses & Anxiety Disorders ; 3313 Gruppen-, Familien- und Partnertherapie ; 3215 Neurosen und Angststörungen ; Posttraumatische Stressreaktionen ; Kinderpsychotherapie ; Emotionales Trauma ; Psychotherapeutische Techniken ; Psychotherapeutische Prozesse ; Kinder ; Posttraumatic Stress Disorder ; War ; Child Psychotherapy ; Emotional Trauma ; Psychotherapeutic Techniques ; Psychotherapeutic Processes ; Children ; Group Psychotherapy ; Victimization ; Gruppenpsychotherapie ; 1040 experience report/case study ; development & evaluation of group therapy program for Bosniac children with war experiences, emotional trauma & victimization & coping behavior ; Psychological Disorders, Mental Health Treatment and Prevention ; psychische Störungen, Behandlung und Prävention ; war ; victimization ; Viktimisierung ; Krieg

journal article, Zeitschriftenartikel

2024-09-19

Soziologie, Anthropologie ; Sociology & anthropology ; Soziologie von Gesamtgesellschaften ; Macrosociology, Analysis of Whole Societies ; Bundesrepublik Deutschland ; bürgerschaftliches Engagement ; Federal Republic of Germany ; citizens' involvement

Zeitschriftenartikel, journal article

2024-08-29

Friederike Schmidt / Anne-Christin Schondelmayer / Ute B. Schröder (Hrsg.): Selbstbestimmung und Anerkennung sexueller und geschlechtlicher Vielfalt: Lebenswirklichkeiten, Forschungsergebnisse und Bildungsbausteine. Wiesbaden: Springer VS 2015. 9783658022518

Sozialwissenschaften, Soziologie ; Social sciences, sociology, anthropology ; Familie / Jugend / Alter; Gender / Körper; Kultur & Medien ; Sozialwissenschaften ; Social Sciences

Rezension, review

2024-10-22

Conspiracy theories gained considerable attention during the Covid-19 pandemic. Although studies have extensively explored their (mostly) negative impacts on various political and social aspects, like participation, health-related behavior, and violence, their influence on support for democracy remains relatively unexplored. The few existing studies offer conflicting findings, prompting my focus to shift from assessing generic support for democracy to examining preferences for alternative decision-making models. To address some limitations of prior research on alternative models of decision-making, I combine a trade-off item with a ranking methodology: respondents were prompted to indicate their first and second preferences for different democratic and non-democratic models over representative democracy. The study is based on data from a representative survey in Germany (July/August 2022; N = 2,536). My findings confirm that the belief in conspiracy theories is positively associated with a preference for direct democratic decision-making. However, conspiracy believers also favor expert-based decision-making over elected politicians - but direct democracy would be their primary choice. Although the evidence for a preference for autocracy over representative democracy is associated with a higher degree of uncertainty, it does suggest that conspiracy believers tend to favor "anything but" representative democracy. These findings contribute to the broader discourse on the impact of conspiracy beliefs on democratic systems.

Politikwissenschaft ; Political science ; conspiracy belief; conspiracy theories ; politische Willensbildung, politische Soziologie, politische Kultur ; Political Process, Elections, Political Sociology, Political Culture ; Technokratie ; direkte Demokratie ; repräsentative Demokratie ; politische Partizipation ; technocracy ; direct democracy ; representative democracy ; political participation

Zeitschriftenartikel, journal article

article

1997

Pädagogik ; Konzept

Klein & groß, Bd. 50 (1997) H. 11/12, S. 20-23, 0863-4386

German

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

Hydrogen containing carbon (C:H) films have been prepared by ion beam deposition of 160 eV ethane ions on a carrier consisting of a Pt(111) single crystal surface covered with a monolayer of graphite. Several monolayers thick films deposited at 350 K contain hydrogen bound to sp, sp2, and sp3 hybridized carbon. Vibrational spectroscopy reveals that thermal D(H) atoms directed to the C:H film surface hydrogenate unsaturated CH groups at the surface and transform sp and sp2 hybridized carbon to sp3. The observed reaction mechanism explains the microscopic processes in chemical erosion of graphite by hydrogen atoms which is a crucial reaction step in the low pressure synthesis of diamondlike carbon.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

The presented work pioneers the embryonic Drosophila CNS for studies of the developmental regulation and function of γ-amino butyric acid (GABA). We describe for the first time the developmental pattern of GABA in Drosophila and address underlying regulatory mechanisms. Surprisingly, and in contrast to vertebrates, detectable levels of GABA occur late during Drosophila neurogenesis, after essential neuronal proliferation and growth have taken place and synaptogenesis has been initiated. This timeline is almost unchanged when the GABA synthetase glutamate decarboxylase (GAD) is strongly misexpressed throughout the nervous system suggesting a tight post-translational regulation of GABA expression. We confirmed such GABA control mechanisms in an independent model system, i.e. primary Drosophila cell cultures raised in elevated [K+]. The data suggest that, in both systems, GABA suppression occurs via control of GAD activity. Using developing embryos and cell cultures as parallel assay systems for pharmacological and genetic studies we show that the negative regulation of GAD can be overridden by drugs known to elevate intracellular free [Ca2+]. Our results provide the basis for investigations of genetic mechanisms underlying the observed phenomenon, and we discuss the potential implications of this work for Drosophila neurogenesis but also for a general understanding of GAD regulation.

Electronic Resource