92,780 research outputs found
Kundgebung des neuen Reichskanzlers Ebert 9. 11. 1918
No full textFriedrich Ebert (geb. 1871), der Vorsitzende der SPD, hat am 9. November das Reichskanzleramt nur widerstrebend angenommen. Als sein Parteifreund Philipp Scheidemann am selben Tag die Republik ausruft und die Abdankung des Kaisers bekanntgibt, ist er ungehalten.Digital imag
Zuverläßige Nachricht von der letzten Staatsveränderung in Dänemark von Jhro Majestät der Königin Caroline Mathilde ...
No full textHrsg. ist der Unterzeichner (handschr.) des Textes auf Bogen A3Zuverläßige Nachricht von der letzten Staatsveränderung in Dänemark von Jhro Majestät der Königin Caroline MathildeVorlageform des Erscheinungsvermerks: A Rotterdam, Chez J. F. Ebert, Libraire sur le Steiger. M D C C L X X I I.Text franz. und dt. - Dt. Text in Fraktu
"Presupuestos participativos en Chile: Experiencias y aprendizajes"
No full textelab. por César Pagliai F. ; Egon Montecinos M.Electronic ed.: Santiago ; Bonn : Friedrich-Ebert-Stiftung, 200
Warum sozio-ökonomische Bildung Teil des Kanons sein sollte
No full textHedtke R. Warum sozio-ökonomische Bildung Teil des Kanons sein sollte. In: Ebert-Stiftung F-, ed. Bildungskanon heute. Berlin: Friedrich-Ebert-Stiftung; 2012: 86-91
AN EBERT SPECTROMETER FOR THE FAR INFRARED
No full textAuthor Institution: Department of Chemistry, The Johns Hopkins UniversityThe design, construction, and performance to date of a 10 in. grating; f/4, vacuum Ebert spectrometer will be described. The wavenumber region between 500 and is currently available using the first and second orders of a 74 grating. The resolution over this region is fairly constant at better than
Agile collaboration for distributed teams
No full textToday software engineering is characterized by two strong trends: agile and distributed. Both together are increasingly demanded and challenge teams and projects due to lack of discipline, insufficient transparency, agile "ping pong" and thus overheads and rework. Authors Fabio Calefato and I describe current technologies and tools for agile collaboration. I look forward to hearing from both readers and prospective column authors about this column and the technologies you want to know more about
Edmund F. Ebert, and S. Sloan Colt, both of New York
No full textBankers See Airport - S. Sloan Colt, right, president of the Bankers Trust Company of New York and a commissioner of the Port of New York Authority, looks over Greater Fort Worth International Airport Friday with Edmund F. Ebert, Bankers Trust Company vice president.https://mavmatrix.uta.edu/specialcollections_startelegram1950s/22622/thumbnail.jp
Converging seasonal prevalence dynamics in experimental epidemics
No full textBackground Regular seasonal changes in prevalence of infectious diseases are often observed in nature, but the mechanisms are rarely understood. Empirical tests aiming at a better understanding of seasonal prevalence patterns are not feasible for most diseases and thus are widely lacking. Here, we set out to study experimentally the seasonal prevalence in an aquatic host-parasite system. The microsporidian parasite Hamiltosporidium tvärminnensis exhibits pronounced seasonality in natural rock pool populations of its host, Daphnia magna with a regular increase of prevalence during summer and a decrease during winter. An earlier study was, however, unable to test if different starting conditions (initial prevalence) influence the dynamics of the disease in the long term. Here, we aim at testing how the starting prevalence affects the regular prevalence changes over a 4-year period in experimental populations.Results In an outdoor experiment, populations were set up to include the extremes of the prevalence spectrum observed in natural populations: 5% initial prevalence mimicking a newly invading parasite, 100% mimicking a rock pool population founded by infected hosts only, and 50% prevalence which is commonly observed in natural populations in spring. The parasite exhibited similar prevalence changes in all treatments, but seasonal patterns in the 100% treatment differed significantly from those in the 5% and 50% treatments. Populations started with 5% and 50% prevalence exhibited strong and regular seasonality already in the first year. In contrast, the amplitude of changes in the 100% treatment was low throughout the experiment demonstrating the long-lasting effect of initial conditions on prevalence dynamics.Conclusions Our study shows that the time needed to approach the seasonal changes in prevalence depends strongly on the initial prevalence. Because individual D. magna populations in this rock pool metapopulation are mostly short lived, only few populations might ever reach a point where the initial conditions are not visible anymore
Ecological and evolutionary dynamics in "Daphnia" metapopulations
No full textMany animal and plant species occur in
metapopulations that are assemblages of spatially
delimited local populations coupled by some degree
of migration. The occupation of habitat patches may
change over time due to local extinction and
colonisation. Migrants colonise empty habitat
patches, which often leads to founder effects. They
may also invade existing populations, and thereby
increase local genetic diversity. Besides gene flow in
the focal species, migrants may evade parasites or
parasites may co-migrate with their hosts. Often,
migrants are not a random subset of their population
of origin, and populations may differ in their
contribution of migrants. Due to the evolutionary and
ecological significance of migrants, it is important to
know their number and populations of origin.
Parasites may drive the evolution within host
populations. But they also influence the success of
migrants and thereby gene flow between populations.
I studied ecological and evolutionary
dynamics in Daphnia metapopulations. Three
interacting species of Daphnia C namely D. magna,
D. longispina and D. pulex C occur sympatrically
along the coast of southwest Finland. They live in
ephemeral freshwater rock pools of various size and
reproduce asexually during most of the summer. The
sexually produced migration stage, the so-called
ephippium, is essential to survive harsh
environmental conditions such as desiccation during
summer or the freezing during winter. There exist
two different hypotheses on the origin of migrants in
this metapopulation. One hypothesis assumes a
Levins' type metapopulation, with no differences
between the patches, while the other suggests a
mainland-island model, where long-lived populations
in large patches are the source of migrants. In a first
step, I quantified the ephippium production of
populations in various sized natural rock pools and in
containers under outdoor conditions. Populations in
larger habitats produced more ephippia but the
increase was much smaller than the increase in
habitat size, and the numerical dominant populations
in small rock pools produced a substantial number of
ephippia.
In the next chapter, I show that desiccation,
which is a common phenomenon in the natural rock
pools, is not detrimental for the populations. This
year's ephippia are sufficient to survive a desiccation
event and an ephippium bank from previous years is
not required. I developed a mathematical model to
predict desiccation for more than 500 individual
pools over 25 years. During warm and dry periods,
evaporation is high and especially shallow pools with
a small surface area and vegetation tend to dry up.
Mevertheless, also these pools with a high risk of
desiccation are often inhabited by Daphnia
populations. Populations in these ephemeral pools are
usually short-lived, but ephippia are especially
exposed to passive dispersal by wind or birds in the
sediments of desiccated pools. I showed that
populations in small pools (less than about 300 l
volume) produced about 50 % of all ephippia.
Rowever, 90 % of all exposed ephippia originated
from these populations. Exposition of ephippia on dry
sediments is practically non-existing in pools larger
than 1000 l. This analysis suggests that populations in
small ephemeral pools are most relevant for the
metapopulation dynamics.
Consistent with the predictions and the
functional understanding of the production of
migrants, I found increased colonisation rates after
warm and dry summers. The weather in southwest
Finland changed in accordance to global climate
change predictions, and this led to increased
dynamics in the metapopulations of the three
Daphnia species. It is the first time that an influence
of climate change on metapopulation dynamics has
been shown. Furthermore, I also found changes in the
whole metacommunity composition, as the three
species reacted differently to climate change.
In the final chapters, I did not focus on
migrants themselves, but investigated proximate
effects of migration. All ephippia can migrate, but the
successful invasion and establishment depends on
fitness components of the hatchlings. For example,
migrants infected with the microsporidium
1ctosporea bayeri are less successful than uninfected
migrants. I was interested in further correlations
between the fitness of a host and its natural infection
status and compared the cost of resistance hypothesis
with the inbreeding-infection hypothesis. I
experimentally confirmed that the naturally observed
infection status has a genetic basis. However, I did
not find a difference in competitive abilities between
naturally uninfected and cured but former infected
genotypes. This suggests that resistance genes
segregate independently of other fitness associated
genes in this system.
A consequence of migration and dispersal is
either the establishment of low-diversity and
potentially parasite-free populations in newly
colonized habitat patches or the introduction of new
host genotypes into already existing populations,
which increases local genetic diversity. Parasites may
either co-migrate with their hosts or arrive
independently in D. magna populations. I thus
compared the epidemiology of O. bayeri in host
populations of low and high genetic diversity.
Following parasite prevalence over two years, I
showed that the parasite spread less successful in host
populations of higher genetic diversity. In the long-
term, this may influence coevolution and hamper
local adaptation of the parasite
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