486 research outputs found
Lichenum Helveticorum Spicilegium
No full textPars prima (1823-1836. - IV, 380 S.) Continens sectiones I - VII, illustrantes lichenum exsiccatorum fasciculos I - XIIPars secunda (1839-1842. - S. 381-632) Continens sectiones VIII - XII, illustrantes lichenum exsiccatorum fasciculos XIII - XVIIIauctore Ludov. Eman. Schaerer ..
New insights on Flavescence dorée phytoplasma ecology in the vineyard agro-ecosystem in southern Switzerland
No full textPhytoplasmas associated with Flavescence dorée (FDp) grapevine disease are quarantine pathogens controlled through mandatory measures including the prompt eradication and destruction of diseased plants, and the insecticide treatments against the insect vector, the ampelophagous leafhopper Scaphoideus titanus. In the present study, a multidisciplinary approach has been applied to investigate the FDp ecological cycle in a test vineyard agro-ecosystem in Canton Ticino, south Switzerland. Despite the scarce population density of S. titanus, a regular trend of new infections (3.4% of the total vines) through the years was observed. The leafhopper Orientus ishidae was found as the most abundant among the captured insect species known as phytoplasma vectors (245 out of 315 specimens). The population of O. ishidae was evidenced prevalently (167 specimens) in the south-western side of the vineyard and within the neighbouring forest constituted mainly by hazel (Corylus avellana) and willow (Salix spp.). These plant species were found infected by FDp related strains (30% of analysed trees) for the first time in this study. Interestingly, O. ishidae was found to harbour FDp related strains in high percentage (26% of the analysed pools). In addition, 16SrV phytoplasma group was detected for the first time in the insect Hyalesthes obsoletus and a FDp related strain in Thamnotettix dilutior, present in low populations within the test vineyard. Molecular characterisation and phylogenetic analyses of methionine aminopeptidase (map) gene sequences of FDp and related strains, here identified, revealed the great prevalence of the map-type FD2 in grapevines (97%) and in O. ishidae pools (72%). Such a map-type was found also in hazel and in T. dilutior, but not in S. titanus. Moreover, map-types FD1 and FD3 were identified for the first time in Switzerland in several host plants and phytoplasma vectors, including grapevine (FD1), S. titanus (FD1) and O. ishidae (FD1 and FD3). Based on the data obtained in this study, it is reasonable to hypothesise that the ecological cycle of FDp could be related not exclusively to the grapevine-specific feeding diet of S. titanus, but it could include other insect vector(s) and/or plant host(s). Further studies will be needed to prove the role of O. ishidae as vector able to transmit FDp from wild plants (e.g. hazel) to grapevine
Realistic ionizing fluxes for young stellar populations from 0.05 to 2 ZÔ
No full textWe present a new grid of ionizing fluxes for O and Wolf–Rayet (W–R) stars for use with evolutionary synthesis codes and single-star H ii region analyses. A total of 230 expanding, non-LTE, line-blanketed model atmospheres have been calculated for five metallicities (0.05, 0.2, 0.4, 1 and 2 Z⊙) using the wm-basic code of Pauldrach, Hoffmann & Lennon for O stars and the cmfgen code of Hillier & Miller for W–R stars. The stellar wind parameters are scaled with metallicity for both O and W–R stars. We compare the ionizing fluxes of the new models with the CoStar models of Schaerer & de Koter and the pure helium W–R models of Schmutz, Leitherer & Gruenwald. We find significant differences, particularly above 54 eV, where the emergent flux is determined by the wind density as a function of metallicity. The new models have lower ionizing fluxes in the He i continuum with important implications for nebular line ratios. We incorporate the new models into the evolutionary synthesis code starburst99 and compare the ionizing outputs for an instantaneous burst and continuous star formation with the work of Schaerer & Vacca (SV98), and Leitherer et al. The changes in the output ionizing fluxes as a function of age are dramatic. We find that, in contrast to previous studies, nebular He ii λ4686 will be at, or just below, the detection limit in low metallicity starbursts during the W–R phase. The new models have lower fluxes in the He i continuum for Z≥ 0.4 Z⊙ and ages ≤7 Myr because of the increased line blanketing. We test the accuracy of the new model atmosphere grid by constructing photoionization models for simple H ii regions, and assessing the impact of the new ionizing fluxes on important nebular diagnostic line ratios. For the case of an H ii region where the ionizing flux is given by the WM-basic dwarf O star grid, we show that He iλ5786/Hβ decreases between 1 and 2 Z⊙ in a similar manner to observations. We find that this decline is caused by the increased effect of line blanketing above solar metallicity. We therefore suggest that a lowering of the upper mass limit at high abundances is not required to explain the diminishing strength of He iλ5786/Hβ , as has been suggested in the past. For an H ii region where the ionizing flux is provided by an instantaneous burst of total mass 106 M⊙ , we plot the softness parameter η' against the abundance indicator R23 for ages of 1–5 Myr. The new models are coincident with the observational data of Bresolin et al., particularly during the W–R phase, unlike the previous models of SV98 which generally over-predict the hardness of the ionizing radiation
Systematische Ganzheitlichkeit : eine methodologische Vermittlung zwischen Perspektivität und Universalität
No full textZusammenfassung:
Diese Untersuchung ist das Ergebnis einer langjährigen Entwicklung, motiviert durch die Erfahrung von Widersprüchen und Zwängen in der internationalen beruflichen Praxis, die eine gründliche Auseinandersetzung mit den Möglichkeiten einer ganzheitlichen Erfassung von Situationen und Zusammenhängen nahe legten. Das Selbstverständnis von Philosophie hat sich dahin gehend entwickelt, Strukturen von Aussagen zu entwerfen und zu debattieren über Dinge und Zustände der Welt. Weil keine der daraus hervorgegangenen Positionen universelle Geltung beanspruchen kann, rivalisiert eine Unzahl von Versuchen, ohne daß eine wirklich ganzheitlich zielführend werden könnte. Im hier vorgelegten Ansatz ist die Grundidee, nicht wie üblich sofort über weltliche Dinge zu urteilen – was prinzipiell zu blinden Flecken und unvollständigen Welt¬bildern führen muß – sondern erst das Instrumentarium des Begrifflichen in seiner Eigendynamik kompromißlos auszuloten, durch welches jede Prädikation erfolgt. Für diese Klärung setzt der hier vorgeschlagene Ansatz beim Gesamtzusammenhang aller potentiellen Begrifflichkeit an, der die streng universell gültigen Ordnungen in der Wirklichkeit zugänglich macht und auch die Basis für die Grundgesetze der Logik bildet.
In der hier vorgelegten Darstellung der Zusammenhänge umfaßt das Vorwort die Bezüge zwischen subjektiver Erfahrung und objektiver Problematik (Kapitel 1). Das Anliegen als solches wird in der einführenden Diskussion diskutiert (Kapitel 2). Die Darstellung erfolgt in sieben Stufen bzw. Unterkapiteln: in 2.1 das Thema ergreifend, um die Basis für die Untersuchung zu legen; 2.2 die Probleme untersuchend zwischen rationalem Zugang und ganzheitlicher Erfassung, dadurch die Lösungsidee grob umreißend; 2.3 die Ursache von Behinderung im ganzheitlichen Erfassenwollen aufgreifend: 'Eingreifen statt Einfühlungsvermögen'; 2.4 die durch diese mentale Attitüde real erzeugte Selbstbegrenzungen auslotend; 2.5 die prinzipielle Vermeidbarkeit von solchen Grenzen erörternd, wie auch deren Auflösbarkeit; 2.6 eine naturgegebene inhalslogische Gesetzmäßigkeit aufspürend, welche im Begrifflichen erfüllt sein muß, wenn lückenlose Begreif¬barkeit erreichbar werden soll; 2.7 den Bezug zum Gesamtzusammenhang als Verbund aller Inhalte umreißend.
Dieser Denkpfad des reinen 'Horchens' kommt ohne jede Voraus-Setzung aus (es müssen aber bestimmte Vor-Bedingungen erfüllt sein); ihn beschreitend, wird die Qualität des vorgeschlagenen Lösungsansatzes – 'systematische Aufmerksamkeit' – allmählich erkennbar. Die ganzheitliche Auslotung der Eigengesetzlichkeit von perspektivischem Denken läßt eine Universalität erreichbar werden, die – im Gegensatz zu den üblichen philosophischen und wissenschaftlichen Methoden – allgemein die Brücke zwischen Perspektivität und Universalität zu schlagen erlaubt. Das Mittel dafür liegt in den grundbegrifflichen Strukturen, welche aus den rein logischen Implikationen eines Frage-Inhalts heraus entfaltet werden können und dann als kategoriale Ganzheit angewendet werden sollten. Die Methode im Vorgehen ist, den Inhalt einer Fragerichtung ganz auf sich selbst anzuwenden (vollständige Selbstbezüglichkeit – die in traditionellen Ansätzen begrenzt ist, aber in rein inhaltslogischem Vorgehen erreichbar). Es kommen die je entsprechenden rein inhaltlich bestimmten und streng polaren Grundbegrifflichkeiten zum Tragen, und das Ergebnis ist die je relevante Vierheit ('Tetrade') von konjugierten Kategorien. Es sind begriffliche Kontinua, welche heuristisch relevant und auf schlechthin alle Strukturen für die phänomenologische Erfassung anwendbar sind, nunmehr mit einer präzisen Ausrichtung. Deshalb bestehen im vorgeschlagenen Ansatz – als 'systematische Aufmerksamkeit' bezeichnet – keine disziplinären Grenzen; im Gegenteil erlaubt er eine prinzipiell unbegrenzte Inter- und Transdiziplinarität.
Um die streng allgemeine Anwendbarkeit dieses Ansatzes nachzuweisen, wird er in Kapitel 3 auf die Geowissenschaften angewandt. Diese Disziplin ist dafür besonders geeignet, weil sie in einem homogenen begrifflichen Instrumentarium die gesamte Spannweite vom Mineralischen über das Vegetabile und Sinnesorientierte bis zum Mentalen und Sozialen klar erfaßbar machen sollte. Just dies ist eine der Stärken des vorgeschlagenen Denkansatzes. Die Problematik wird im Unterkapitel 3.1 angegangen durch eine Erörterung der methodologischen Desiderate, dabei die Mathematik und Thermodynamik erörternd als eine Art von lingua franca zwischen heutigen wissenschaftlichen Disziplinen allgemein. Anschließend werden in Unterkapitel 3.2 die Bereiche in den Geowissenschaften kurz im Lichte der 'systematischen Aufmerksamkeit' beleuchtet: (1) physische Geographie als 'Speicher', 'Regler' und 'Prozeß', (2) Klimakunde / Meteorologie als 'Energie' und 'Information', (3) Bodenkunde als Verbindungsort von Anorganik und Organik, (4) Geoökologie mit den 'homogenen Einheiten' der naturräumlichen Gliederung, (5) Biogeographie mit den Biozönosen, Biotopen, und den Stufen des Organischen, (6) Humangeographie mit der Autonomie und Heteronomie des Menschen in seiner individuellen und sozialen Organisation, (7) theoretische Geowissenschaft als Ort der prinzipiellen Integration aller Seinsebenen. In Unterkapitel 3.3 wird noch kurz die Eigengesetzlichkeit der Einwirkung des Menschen auf die Natur umrissen.
Kapitel 4 versammelt kurze Kommentare zu den akkumulierten Publikationen. Nach Glossar und Literatur folgen in einem Quasi-Kapitel 5 die neun akkumulierten Publikationen selbst. Die Untersuchung als Ganze ist durchgehend paginiert.
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Summary:
In my professional life, partly in international planning and urban design, I experienced massive contradictions in the official line of thought, producing unnecessary conflict. Philosophy has developed a self-concept of devising and debating structures of statements and states of worldly affairs. Since no attempt of this sort can ever achieve a strictly complete grasp and universal validity, myriads of them are rivaling, but ultimately all have some flaw. This complex of problems motivated me to go back to university for meditating on integral ways of thinking. The presented investigation is the end result, now molded into a methodological system. The basic idea in the presented approach is not, as usual, to predicate immediately on worldly objects – which inevitably leads to blind spots and incomplete world-views – but to fathom first of all the instrumentation in the conceptual realm with its inherent self-dynamics that underlies all forms of predication. For achieving this objective, the proposed approach sets out on the characteristics of interconnectedness in all potential conceptuality, which allows the universally valid form of order securely to be approached that constitutes also the matrix for the fundamental laws of logic.
In the presented investigation, 'Vorwort' means Preface and covers as chapter 1 the relation between subjective authorship and objective questions as implied by the chosen topic. 'Einleitung' means Introduction and features as chapter 1 the issues that follow objectively from the discussed subject matter, namely integral ways of understanding and being, which determine therefore the approach and the method. This chapter offers also an overview over the structure of the problem and possible remedies, working through it in seven steps: in subchapter (2.1) taking hold of its meaning, its intrinsic content, (2.2) outlining a rational approach to this content, and discovering that problems in integral understanding are not imposed by nature, but man-made, (2.3) revealing how habitual approaches manifest – even in pure brain work – not empathy, but a powerful intervention, by setting out on basic assumptions, fundamental beliefs, (2.4) showing the actual results of such interventions, thereby disclosing the type of initiative that allows the problems to be dissolved, (2.5) actually possible procedures for avoiding on principle the occurrence of such discontinuities, (2.6) finding a law of content logic that determines the conceptual conditions for intelligibility and is at the root of the basic laws of formal logic, thereby warranting the general resolvability of the approached complex of problems, (2.7) outlining the bearings of the proposed approach (dubbed 'systematic attentiveness') in the overall interrelations, which the proposed approach allows to be viewed as an ordered complex.
The outlined procedure of pure 'listening' can do without any kind of presupposition (while certain preconditions must be fulfilled) and gradually makes intelligible the integral quality of the proposed approach. Fathoming perspectivity in this way fosters a universality that allows – in contrast to usual procedures in philosophy and science – the gap between the two aspects to be bridged. The means for this conciliation reside in the fundamental conceptual structures that can be unfolded out of the purely logical implications of any given query content and should then be applied as a categorial wholeness. The method in proceeding is to apply the given query content onto itself (complete self-referentiality – which is limited in traditional approaches, but attainable in pure content logic). The fundamental conceptual structures that follow in pure content logic from the chosen or given query content can then take effect, and the end result is the respective fourness ('tetrad') of conjugated categories. These constitute conceptual continua that are relevant on the heuristic level and applicable to all structures in phenomenological observation, now in a precise alignment. Due to this quality, the proposed approach – dubbed 'systematic attentiveness' – has no disciplinary limits; on the contrary it allows an inter- and trans-disciplinarity that is on principle unlimited.
For verifying the general applicability of 'systematic attentiveness', this approach is applied in chapter (3) to the geosciences because this discipline should cover the full scope from mineral existence to vegetal, sensory and mental life, up to social organization, including all interactions, in a conceptually homogenous way. Subchapter (3.1) contains some general considerations on the theoretical level, broaching the issue of mathematics as lingua franca in the sciences, as well as problems in interpreting thermodynamics, for indicating in (3.2) the applicability of the proposed approach in pivotal sub-disciplines of the geosciences: physical geography (with its categories of 'accumulator', 'regulator' and 'process'), climate studies ('energy' and 'information'), lithosphere (the locus of interlacing inert and alive structures), geoecology, biogeography, human geography, and purely theoretical geosciences, concluding (3.3) with issues of human action on nature.
Chapter (4) consists of brief comments to the accumulated articles that follow as such in the fifth and last part of this study. These nine publications reveal other aspects of applicability. They contain some redundancies due to a need of exposing my critique and approach again and again. Most of the papers are written in English, so for Anglophone readers they are self-explanatory
An optical and infrared analysis of blue compact dwarf galaxies
No full textAn understanding of Blue Compact Dwarf galaxies (BCDs) and the processes occurring within
their chemically un-evolved environments is fundamental in our understanding of the early universe.
This thesis presents an investigation into their physical conditions, kinematics, chemical
abundances and dust compositions.
An optical integral field spectroscopy investigation of two perturbed BCDs, UM420 and UM462,
is presented. Emission line maps show that both galaxies display signs of ongoing perturbation
and/or interaction. Electron temperatures, densities and chemical abundances are computed from
spectra integrated over the whole galaxies and for each area of star formation.
A similar yet more complicated analysis is undertaken of the BCD Mrk996, which displays
multi-component emission lines. The high excitation energy [O III] \lambda4363 and [N II] \lambda5755 lines
are detected only in the inner regions and purely in broad component form, implying unusual
excitation conditions. A separate physical analysis of the broad and narrow emission line regions
is undertaken, yielding a revised metallicity and N/O ratio typical for the galaxy’s metallicity.
The mid-IR properties of 19 BCDs are studied through Spitzer spectral and imaging data. The
depeletion of PAH emission in BCDs is investigated and found to be due to formation and destruction
effects. The [S III] flux ratio is used as a density diagnostic, showing typically low-densities.
Maps of PAH emission and radiation field hardness are derived from IRS spectral mapping data.
Blackbody fits to IR photometric SEDs typically reveal two dust components.
The observed physical and chemical properties of Mrk 996 are successfully reproduced using
the photoionisation code MOCASSIN. The best-fit model involved the inclusion of a filling factor
and an amorphous carbon dust component with a two-zone dust distribution. A STARBURST99
input spectrum was used, yielding ages consistent with the known young WR stars and old super
star clusters within Mrk 996
Schaerer, Richard R. (Death, 1898-03-07)
No full textAddress: 1802 Denham St.Age at death: 2mo.Pg 23/1898/123/MW S/City/Theo./Bange/P. Rebold/Walnut HillsOriginal record filed in drawer labeled 'SCHAD-SHAW'
The role of background movement in goldfish vision.
No full textIn experiments described in the literature objects presented to restrained goldfish failed to induce eye movements like fixation and/or tracking. We show here that eye movements can be induced only if the background (visual surround) is not stationary relative to the fish but moving. We investigated the influence of background motion on eye movements in the range of angular velocities of 5-20 degrees s(-1). The response to presentation of an object is a transient shift in mean horizontal eye position which lasts for some 10 s. If an object is presented in front of the fish the eyes move in a direction such that it is seen more or less symmetrically by both eyes. If it is presented at +/- 70 degrees from the fish's long axis the eye on the side of the object moves in the direction that the object falls more centrally on its retina. During these object induced eye responses the typical optokinetic nystagmus of amplitude of some 5 degrees with alternating fast and slow phases is maintained, and the eye velocity during the slow phase is not modified by presentation of the object. Presenting an object in front of stationary or moving backgrounds leads to transient suppression of respiration which shows habituation to repeated object presentations
The brightest Ly alpha emitter : Pop III or black hole?
No full textCR7 is the brightest z = 6.6 Ly alpha emitter (LAE) known to date, and spectroscopic follow-up by Sobral et al. suggests that CR7 might host Population (Pop) III stars. We examine this interpretation using cosmological hydrodynamical simulations. Several simulated galaxies show the same 'Pop III wave' pattern observed in CR7. However, to reproduce the extreme CR7 Ly alpha/He II1640 line luminosities (L-alpha/He II) a top-heavy initial mass function and a massive (greater than or similar to 10(7)M(circle dot)) Pop III burst with age less than or similar to 2 Myr are required. Assuming that the observed properties of Ly alpha and He II emission are typical for Pop III, we predict that in the COSMOS/UDS/SA22 fields, 14 out of the 30 LAEs at z = 6.6 with L-alpha > 10(43.3) erg s(-1) should also host Pop III stars producing an observable L-He II greater than or similar to 10(42.7) erg s(-1). As an alternate explanation, we explore the possibility that CR7 is instead powered by accretion on to a direct collapse black hole. Our model predicts L-alpha, L-He II, and X-ray luminosities that are in agreement with the observations. In any case, the observed properties of CR7 indicate that this galaxy is most likely powered by sources formed from pristine gas. We propose that further X-ray observations can distinguish between the two above scenarios
The formation history of the Galactic bulge
No full textThe distributions of the stellar metallicities of K giant stars in several fields of the Galactic bulge, taken from the literature and probing projected Galactocentric distances of similar to500 pc to similar to3 kpc, are compared with a simple model of star formation and chemical evolution. Our model assumes a Schmidt law of star formation and is described by only a few parameters that control the infall and outflow of gas and the star formation efficiency. Exploring a large volume of parameter space, we find that very short infall time-scales are needed (less than or similar to0.5 Gyr), with durations of infall and star formation greater than 1 Gyr being ruled out at the 90 per cent confidence level. The metallicity distributions are compatible with an important amount of gas and metals being ejected in outflows, although a detailed quantification of the ejected gas fraction is strongly dependent on a precise determination of the absolute stellar metallicities. We find a systematic difference between the samples of Ibata & Gilmore, at projected distances of 1-3 kpc, and the sample in Baade's window (Sadler et al.). This could be caused either by a true metallicity gradient in the bulge or by a systematic offset in the calibration of [Fe/H] between these two samples. This offset does not play an important role in the estimate of infall and formation time-scales, which are mostly dependent on the width of the distributions. The recent bulge data from Zoccali et al. are also analysed, and the subsample with subsolar metallicities still rules out infall time-scales greater than or similar to1 Gyr at the 90 per cent confidence level. Hence, the short time-scales we derive based on the observed distribution of metallicities are robust and should be taken as stringent constraints on bulge formation models
Low-redshift Lyman continuum leaking galaxies with high [O iii]/[O ii] ratios
No full textWe present observations with the Cosmic Origins Spectrograph (COS) onboard the Hubble Space Telescope of five star-forming galaxies at redshifts z in the range 0.2993-0.4317 and with high emission-line flux ratios O-32 = [O III]lambda 5007/[O II]lambda 3727 similar to 8-27 aiming to detect the Lyman continuum (LyC) emission. We detect LyC emission in all galaxies with the escape fractions f(esc)(LyC) in a range of 2-72 per cent. A narrow Ly alpha emission line with two peaks in four galaxies and with three peaks in one object is seen in medium-resolution COS spectra with a velocity separation between the peaks V-sep varying from similar to 153 to similar to 345 km s(-1). We find a general increase of the LyC escape fraction with increasing O-32 and decreasing stellar mass M-star, but with a large scatter of f(esc)(LyC). A tight anticorrelation is found between f(esc)(LyC) and V-sep making V-sep a good parameter for the indirect determination of the LyC escape fraction. We argue that one possible source driving the escape of ionizing radiation is stellar winds and radiation from hot massive stars
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