6,435 research outputs found
Morphology of Salina offshore (Southern Tyrrhenian Sea)
In this paper, we present the first complete morphological map of the Salina offshore at a scale
of 1:100,000. The submarine flanks of the Salina edifice extend down to −650 to −1300 m, are
steep and characterized by an uneven morphology due to the presence of volcanic and erosivedepositional
features. The volcanic features cover ∼30% of the submarine portion and include
volcanic cones and bedrock outcrops. The remaining ∼70% is affected by a wide series of
erosive-depositional features. Among these, features related to Late Quaternary sea level
fluctuations comprise the insular shelf surrounding the island and overlying submarine
terraced depositional sequences. Mass-wasting features include landslide scars, channels, fanshaped
deposits and waveforms. The presented map provides useful insights for a better
understanding of the morphological evolution of the edific
Besatzungskinder: Die schweigenden Geister des zweiten Weltkrieges (Besatzungskinder: The Silenced Ghosts of the Second World War)
Diese Forschungsarbeit konzentriert sich auf die Erfahrung von Besatzungskindern in Deutschland nach dem Zweiten Weltkrieg. Sie diskutiert die Exposition oder mangelnde Sichtbarkeit von Besatzungskindern in der Gesellschaft und wie sie kulturell dargestellt wurden. Diese These stellt die Frage, wie Besatzungskinder in der Gesellschaft gesehen wurden, und ob die Gesellschaft ihnen half, eine deutsche Identität zu entwickeln
Combining Hebbian and reinforcement learning in a minibrain model
A toy model of a neural network in which both Hebbian learning and
reinforcement learning occur is studied. The problem of `path interference',
which makes that the neural net quickly forgets previously learned input-output
relations is tackled by adding a Hebbian term (proportional to the learning
rate ) to the reinforcement term (proportional to ) in the learning
rule. It is shown that the number of learning steps is reduced considerably if
, i.e., if the Hebbian term is neither too small nor too
large compared to the reinforcement term
Morphology of Lipari offshore (Southern Tyrrhenian Sea)
High-resolution multibeam bathymetry was recently collected around Lipari, the largest and
most densely populated island of the Aeolian Archipelago (Southern Tyrrhenian Sea). The
data were acquired within the context of marine geological studies performed in the area
over the last 10 years. We present the first detailed morphological map of the Lipari
offshore at 1:100,000 scale (Main Map). A rugged morphology characterizes the submarine
portions of Lipari volcano, reflecting both volcanic and erosive-depositional processes. The
volcanic features include cones, lava flows and bedrock outcrops. Erosive-depositional
features include an insular shelf topped by submarine depositional terraces related to LateQuaternary
sea-level fluctuations, as well as landslide scars, channelized features, fanshaped
deposits and wavy bedforms. The different distribution of volcanic and erosivedepositional
features on the various sectors of Lipari is mainly related to the older age of the
western flank with respect to the eastern one. The map also provides insights for a first
marine geohazard assessment of this active volcanic area
The first ultra-high resolution Digital Terrain Model of the shallow-water sector around Lipari Island (Aeolian Islands, Italy)
Very high resolution bathymetric map obtained through multibeam echosounders
data are crucial to generate accurate Digital Terrain Models
from which the morphological setting of active volcanic areas can be analyzed
in detail. Here we show and discuss the main results from the first
multibeam bathymetric survey performed in shallow-waters around the island
of Lipari, the largest and the most densely populated of the Aeolian
Islands (southern Italy). Data have been collected in the depth range of
0.1-150 m and complete the already existent high-resolution multibeam
bathymetry realized between 100 and 1300 m water depth. The new ultrahigh
resolution bathymetric maps at 0.1-0.5 m provide new insights on the
shallow seafloor of Lipari, allowing to detail a large spectrum of volcanic,
erosive-depositional and anthropic features. Moreover, the presented data
allow outlining the recent morphological evolution of the shallow coastal
sector of this active volcanic island, indicating the presence of potential
geo-hazard factors in shallow waters
Embedded 45° micro-mirror for out-of-plane coupling in optical PCBs
We present an embedded 45° micro-mirror that can be used to couple light out-of-plane of the optical layer. The discrete
micro-mirror is inserted in a micro-cavity into the optical layer. Loss measurements at receiver side show a mirror loss as low as
0.35dB
A Heterosynaptic Learning Rule for Neural Networks
In this article we intoduce a novel stochastic Hebb-like learning rule for
neural networks that is neurobiologically motivated. This learning rule
combines features of unsupervised (Hebbian) and supervised (reinforcement)
learning and is stochastic with respect to the selection of the time points
when a synapse is modified. Moreover, the learning rule does not only affect
the synapse between pre- and postsynaptic neuron, which is called homosynaptic
plasticity, but effects also further remote synapses of the pre- and
postsynaptic neuron. This more complex form of synaptic plasticity has recently
come under investigations in neurobiology and is called heterosynaptic
plasticity. We demonstrate that this learning rule is useful in training neural
networks by learning parity functions including the exclusive-or (XOR) mapping
in a multilayer feed-forward network. We find, that our stochastic learning
rule works well, even in the presence of noise. Importantly, the mean learning
time increases with the number of patterns to be learned polynomially,
indicating efficient learning.Comment: 19 page
Functional consequences of sphingomyelinase-induced changes in erythrocyte membrane structure.
Inflammation enhances the secretion of sphingomyelinases (SMases). SMases catalyze the hydrolysis of sphingomyelin into phosphocholine and ceramide. In erythrocytes, ceramide formation leads to exposure of the removal signal phosphatidylserine (PS), creating a potential link between SMase activity and anemia of inflammation. Therefore, we studied the effects of SMase on various pathophysiologically relevant parameters of erythrocyte homeostasis. Time-lapse confocal microscopy revealed a SMase-induced transition from the discoid to a spherical shape, followed by PS exposure, and finally loss of cytoplasmic content. Also, SMase treatment resulted in ceramide-associated alterations in membrane-cytoskeleton interactions and membrane organization, including microdomain formation. Furthermore, we observed increases in membrane fragility, vesiculation and invagination, and large protein clusters. These changes were associated with enhanced erythrocyte retention in a spleen-mimicking model. Erythrocyte storage under blood bank conditions and during physiological aging increased the sensitivity to SMase. A low SMase activity already induced morphological and structural changes, demonstrating the potential of SMase to disturb erythrocyte homeostasis. Our analyses provide a comprehensive picture in which ceramide-induced changes in membrane microdomain organization disrupt the membrane-cytoskeleton interaction and membrane integrity, leading to vesiculation, reduced deformability, and finally loss of erythrocyte content. Understanding these processes is highly relevant for understanding anemia during chronic inflammation, especially in critically ill patients receiving blood transfusions
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