Rain, winds and haze during the Huygens probe's descent to Titan's surface.

The irreversible conversion of methane into higher hydrocarbons in Titan's stratosphere implies a surface or subsurface methane reservoir. Recent measurements from the cameras aboard the Cassini orbiter fail to see a global reservoir, but the methane and smog in Titan's atmosphere impedes the search for hydrocarbons on the surface. Here we report spectra and high-resolution images obtained by the Huygens Probe Descent Imager/Spectral Radiometer instrument in Titan's atmosphere. Although these images do not show liquid hydrocarbon pools on the surface, they do reveal the traces of once flowing liquid. Surprisingly like Earth, the brighter highland regions show complex systems draining into flat, dark lowlands. Images taken after landing are of a dry riverbed. The infrared reflectance spectrum measured for the surface is unlike any other in the Solar System; there is a red slope in the optical range that is consistent with an organic material such as tholins, and absorption from water ice is seen. However, a blue slope in the near-infrared suggests another, unknown constituent. The number density of haze particles increases by a factor of just a few from an altitude of 150 km to the surface, with no clear space below the tropopause. The methane relative humidity near the surface is 50 per cent.

Optical observations of comet Hale-Bopp (C/1995 O1) at large heliocentric distances before perihelion.

The activity of comet Hale-Bopp (C/1995 O1) was monitored monthly by optical imaging and long-slit spectroscopy of its dust and gas distribution over heliocentric distances of 4.6 to 2.9 astronomical units. The observed band intensities of the NH2 radical and the H2O+ ion cannot be explained by existing models of fluorescence excitation, warranting a reexamination of the corresponding production rates, at least at large heliocentric distances. Comparing the production rate of the CN radical to its proposed parent, HCN, shows no evidence for the need of a major additional source for CN in Hale-Bopp at large heliocentric distances. The dust and CN production rates are consistent with a significant amount of sublimation occurring from icy dust grains surrounding Hale-Bopp.

Surface changes on comet 67P/Churyumov-Gerasimenko suggest a more active past.

The Rosetta spacecraft spent ~2 years orbiting comet 67P/Churyumov-Gerasimenko, most of it at distances that allowed surface characterization and monitoring at submeter scales. From December 2014 to June 2016, numerous localized changes were observed, which we attribute to cometary-specific weathering, erosion, and transient events driven by exposure to sunlight and other processes. While the localized changes suggest compositional or physical heterogeneity, their scale has not resulted in substantial alterations to the comet's landscape. This suggests that most of the major landforms were created early in the comet's current orbital configuration. They may even date from earlier if the comet had a larger volatile inventory, particularly of CO or CO2 ices, or contained amorphous ice, which could have triggered activity at greater distances from the Sun.

Rosetta's comet 67P/Churyumov-Gerasimenko sheds its dusty mantle to reveal its icy nature.

The Rosetta spacecraft has investigated comet 67P/Churyumov-Gerasimenko from large heliocentric distances to its perihelion passage and beyond. We trace the seasonal and diurnal evolution of the colors of the 67P nucleus, finding changes driven by sublimation and recondensation of water ice. The whole nucleus became relatively bluer near perihelion, as increasing activity removed the surface dust, implying that water ice is widespread underneath the surface. We identified large (1500 square meters) ice-rich patches appearing and then vanishing in about 10 days, indicating small-scale heterogeneities on the nucleus. Thin frosts sublimating in a few minutes are observed close to receding shadows, and rapid variations in color are seen on extended areas close to the terminator. These cyclic processes are widespread and lead to continuously, slightly varying surface properties.

Hydraulic flow characteristics in the lignotuberous mallee Eucalyptus behriana F. Muell. in the field.

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.

Carbon relations and competition between woody species in a Central European hedgerow : I. Photosynthetic characteristics.

The CO2 uptake capacity of leaves of five competing woody species in an undisturbed developing Central European hedgerow was investigated for possible factors determining competitive ability in the field. Light-saturated maximal CO2 uptake (A max) showed species-specific seasonal variations in Prunus spinosa, a bushlike pioneer on fallow land, in Crataegusxmacrocarpa and Acer campestre, two treelike species dominating the canopy, in Rubus corylifolius, a pioneer liane, and in Ribes uva-crispa, a shrubby undergrowth species. In fully-expanded sun leaves of Prunus, Crataegus and Acer A max ranged from 8 to 12 µmol m-2 s-1 while it ranged from 6 to 15 µmol m-2 s-1 in Rubus and Ribes. The temperature responses showed no difference among species. Neither leaf photosynthetic capacity nor nutrient use of carbon fixation determined competitive ability. Differences between species in the capacity of leaves to adapt to shade resulted in differences in species' establishment in the understory and demonstrated the importance of growth in order to escape light-limiting conditions. A specific sequence of species was found for the range of A max in sun leaves. It was highest in an early pioneer of low competitive ability (Rubus), medium in a later pioneer (Prunus) and in successional plants (Crataegus, Acer), and lowest in the climax species of high competitive ability, Fagus silvatica, (3-4 µmol m-2 s-1; Schulze 1970).

Carbon relations and competition between woody species in a Central European hedgerow : II. Stomatal responses, water use, and hydraulic conductivity in the root/leaf pathway.

Responses of stomata to humidity, light intensity, and leaf water status were investigated throughout a growth season under field conditions for five competing woody species dominating in various stages of a Central European hedgerow. Humidity sensitivity of stomata varied between species. Leaf conductance to H2O, g, as measured in steady-state humidity response curves under constant climatic conditions, remained on high summer levels in Prunus and Crataegus, and on a lower level in Acer, but fell from a high spring level to a low summer level in Ribes and Rubus. The effect of partial stomatal closure in dry air on CO2 uptake, A, varied seasonally and between species. Responses of stomata to light, measured by tracking gas exchange in the field but for controlled climatic conditions, were hyperbolic, similar to CO2 assimilation. The relationship between g and A at variable irradiance was always linear and depended on the species investigated and on the leaf age. In no case did stomata respond to short-term (hourly) changes in leaf water potential (up to 13.5 bar).A low leaf conductance level appeared to be correlated with low hydraulic conductivity in the plant, G, whereas high G in most cases coincided with high stomatal conductances. In Ribes and Rubus G and stomatal opening at maximum CO2 uptake varied in parallel during the season at high soil water content, suggesting a root/stomata interaction independent of plant water status. Water use efficiency (WUE, at certain leaf/air water vapour concentration differences), as determined from light and humidity responses of stomata and CO2 assimilation, was high in species of low G (Ribes, Rubus), and low in species of high G (Prunus, Crataegus). Surprisingly, species of low WUE optimized gas exchange in the sense of Cowan and Farquhar's (1977) theory, where stomata maximized CO2 uptake at a certain water loss within a certain period, while species of high WUE did not optimize in this sense. Other control mechanisms at the leaf level independent from optimization may be involved.It appeared that low G and loss of humidity sensitivity of stomata in Ribes limited distribution of this species outside the half shade of the hedgerow, as exposed plant parts desiccated on dry days. However, water use efficiency per se did not determine species-specific competitive ability, as it was highest in species of low competitive strength.

Carbon relations and competition between woody species in a Central European hedgerow : III. Carbon and water balance on the leaf level.

Annual carbon and water balances of sun leaves were measured in the field for five competing woody hedgerow species of different successional stages. They were compared with carbon and water budgets of climax species from the literature. Climatic limitation of primary production, the effectiveness of leaf photosynthetic capacity in relation to actual carbon gain, costs and time of leaf formation and amortization, and net dry matter gain from the leaf were determined. Their relevance for a species' position during a natural succession from pioneer-invaded fallow land to a climax beech forest in Central Europe is discussed.

Effects of day-to-day changes in root temperature on leaf conductance to water vapour and CO2 assimilation rates of Vigna unguiculata L. Walp.

Leaf gas exchange of Vigna unguiculata was influenced by short-term (day-to-day) changes in soil temperature and the response depended upon the aerial environment. When aerial conditions were constant at 30° C leaf temperature, high air humidity and moderate quantum flux, CO2 assimilation rate and leaf conductance increased with increases in soil temperature from 20 to 35° C, and this response was reversible. Decreases in CO2 assimilation rate and leaf conductance were observed at root temperatures above 30° C when root temperatures were increased from 20° C to 40° C and when air humidity was decreased in steps during the day. In contrast, varying soil temperatures between 20 to 35° C had no influence on gas exchange when shoots were subjected to a wide range of temperatures during each day.The gain ratio ∂A/τE remained constant at different air humidities when root temperature was less than or equal to 30° C indicating optimal gas exchange regulation, but changed with humidity at higher root temperatures. Leaf conductance responded independently from leaf water potential which remained relatively constant during individual experiments.The results indicate that plant responses to high root temperatures may have relevance to plant performance in semi-arid environments. They also illustrate the importance of controlling soil temperatures when studying the responses of potted plants in controlled aerial environments.

Soil drying and its effect on leaf conductance and CO2 assimilation of Vigna unguiculata (L.) Walp : I. The response to climatic factors and to the rate of soil drying in young plants.

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.

Carbon fixation in eucalypts in the field : Analysis of diurnal variations in photosynthetic capacity.

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.

Compensating effects to growth of carbon partitioning changes in response to SO2-induced photosynthetic reduction in radish.

Exposure of plants to SO2 reduced their photosynthetic performance due tio reductions in carboxylating capacity. Although the reduced carbon gain resulted in a lower growth rate of SO2-exposed plants over that of controls, their loss of potential growth was minimized because of proportional increases in allocation to new leaf material.

[The beginnings of child analysis]. / Aus den Anfängen der Kinderanalyse.

The notions hitherto existing of the beginnings of child analysis have to be rectified. The meaning of childhood neuroses within the scope of scientific theory, i.e. the sexual genesis of the neuroses can no longer be maintained. The approach of distinguishing between the latent period and the Oedipus complex as the two phases of sexual development can nowadays be considered to be refuted. The personality of the first children's analyst--Hermine Hug-Hellmuth--needs to be redescribed. She fell victim to her father-transference and deceased murdered by her nephew with the help of whom she had satisfied her own scientific ambitions.

[Course and prognosis of anorexia nervosa: catamnesis of 41 patients]. / Zu Verlauf und Prognose der Anorexia nervosa: Katamnese von 41 Patienten.

The purpose of the following study was a multidimensional assessment of the course of anorexia nervosa. In our follow-up-study we were able to examine 41 out of 51 patients meeting DMS-111 R criteria for anorexia nervosa in our department at a mean follow-up of 5.3 years. At the first evaluation the patients were characterized by an early age of onset (mean 14.2 years), no or very little previous psychiatric treatment, and restrictive eating habits (72.5%); the mean age was 15.2 years. At the time of follow-up, the physical outcome was unfavourable for 50% of the patients; one patient had died. The psychosocial outcome was less favourable for 60%. Against the background of a neurotic structure, social and sexual disturbances were found although the patient's weight was often normal. Depressive symptoms and a "slimness ideal" were found among a large number of patients, just as much as the fear of gaining weight--which prove to be a reliable indicator for the continuation of an eating disorder. A multidimensional evaluation facilitates an assessment of the determinants of prognosis. Previous psychiatric treatment and low body weight were associated with an unfavourable, mention of problems/disturbances in the family environment with a good somatic outcome. Outpatient treatment indicates a favourable psychosocial outcome.

Images of asteroid 21 Lutetia: a remnant planetesimal from the early Solar System.

Images obtained by the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) cameras onboard the Rosetta spacecraft reveal that asteroid 21 Lutetia has a complex geology and one of the highest asteroid densities measured so far, 3.4 ± 0.3 grams per cubic centimeter. The north pole region is covered by a thick layer of regolith, which is seen to flow in major landslides associated with albedo variation. Its geologically complex surface, ancient surface age, and high density suggest that Lutetia is most likely a primordial planetesimal. This contrasts with smaller asteroids visited by previous spacecraft, which are probably shattered bodies, fragments of larger parents, or reaccumulated rubble piles.

E-type asteroid (2867) Steins as imaged by OSIRIS on board Rosetta.

The European Space Agency's Rosetta mission encountered the main-belt asteroid (2867) Steins while on its way to rendezvous with comet 67P/Churyumov-Gerasimenko. Images taken with the OSIRIS (optical, spectroscopic, and infrared remote( )imaging system) cameras on board Rosetta show that Steins is an oblate body with an effective spherical diameter of 5.3 kilometers. Its surface does not show color variations. The morphology of Steins is dominated by linear faults and a large 2.1-kilometer-diameter crater near its south pole. Crater counts reveal a distinct lack of small craters. Steins is not solid rock but a rubble pile and has a conical appearance that is probably the result of reshaping due to Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) spin-up. The OSIRIS images constitute direct evidence for the YORP effect on a main-belt asteroid.