182 research outputs found
Fossil overpressures compartments? A case study from the Eifel area and some general aspects
Fluid overpressures are well known from
hydrocarbon exploration in many sedimentary
basins. They can reach almost
lithostatic values, and may cause
the fracturing of rock. Fracturing allows
the discharge of fluid overpressure, and
fluid flows along a hydraulic gradient towards
a low pressure reservoir. Different
mechanisms may cause the precipitation
from the fluid, such as a fluid pressure drop, a variation of temperature
at the low pressure reservoir, or
a different rock type inducing different
Eh-pH conditions. Such precipitates
in fractures are called veins, which often
display paleo-fluid overpressures in
rocks. In this study, we present some results
from Devonian clastic sedimentary
rocks of the Eifel area. Results are compared
with other sedimentary basins to
highlight some general aspects.conferenc
Innovative Work Behavior: To What Extent and How Can HRM Practices Contribute to Higher Levels of Innovation Within SMEs?
In this chapter, the influence of HR practices and more specifically the Ned Herrmanns development tool HBDI on the development of innovative work behavior (IWB) is described. Innovative work behavior today is important for organizations to stay in a competitive position. Also for small and medium-sized enterprises (SMEs), like the case study in this chapter, innovation is essential to keep the SME’s competitive advantage. As people are the most important resource in service companies, and they can contribute to innovation via their motivation and skills, the role of human resource management is important. In this book chapter, we analyze the positive influence of various HR practices on IWB. One of these HR practices is the HBDI tool, a specifically designed questionnaire which gives people insight into their problem-solving styles. The outcomes of the study in this chapter show that both HR practices and also the HBDI tool have a positive influence on developing innovative work behavior and on innovation performance
Физика пробоя жидких диэлектриков (История и современное состояние, вклад советских и российских ученых)
Дана краткая история развития учения об электрическом пробое диэлектрических жидкостей, совершенствования техники и методики исследования этого явления. Показано, что по целому ряду направлений советские (российские) ученые и, в частности, сотрудники Томского политехнического университета опережали зарубежных коллег и внесли определяющий вклад в понимание механизмов пробоя жидкостей. Представлены современные физические модели инициирования и развития разряда при импульсном воздействии напряжения
The effect of secondary electrons on radiolysis as observed by in liquid TEM: The role of window material and electrical bias
The effect of window material on electron beam induced phenomena in liquid phase electron microscopy (LPEM) is an interesting yet under-explored subject. We have studied the differences of electron beam induced gold nanoparticle (AuNP) growth subject to three encapsulation materials: Silicon Nitride (Si3N4), carbon and formvar. We find Si3N4 liquid cells (LCs) to result in significantly higher AuNP growth yield as compared to LCs employing the other two materials. In all cases, an electrical bias of the entire LC structures significantly affected particle growth. We demonstrate an inverse correlation of the AuNP growth rate with secondary electron (SE) emission from the windows. We attribute these differences at least in part to variations in SE emission dynamics, which is seen as a combination of material and bias dependent SE escape flux (SEEF) and SE return flux (SERF). Furthermore, our model predictions qualitatively match electrochemistry expectations
Two-point phase correlations of a one-dimensional bosonic Josephson junction
We realize a one-dimensional Josephson junction using quantum degenerate Bose
gases in a tunable double well potential on an atom chip. Matter wave
interferometry gives direct access to the relative phase field, which reflects
the interplay of thermally driven fluctuations and phase locking due to
tunneling. The thermal equilibrium state is characterized by probing the full
statistical distribution function of the two-point phase correlation.
Comparison to a stochastic model allows to measure the coupling strength and
temperature and hence a full characterization of the system
Stochastic optimization of a cold atom experiment using a genetic algorithm
We employ an evolutionary algorithm to automatically optimize different
stages of a cold atom experiment without human intervention. This approach
closes the loop between computer based experimental control systems and
automatic real time analysis and can be applied to a wide range of experimental
situations. The genetic algorithm quickly and reliably converges to the most
performing parameter set independent of the starting population. Especially in
many-dimensional or connected parameter spaces the automatic optimization
outperforms a manual search.Comment: 4 pages, 3 figure
Spatial and temporal distribution of sperm whales (Physeter macrocephalus) within the Kaikoura submarine canyon in relation to oceanographic variables
The Kaikoura area is a valuable feeding spot for sperm whales with the presence of a submarine canyon close to shore. Male sperm whales can be found there year around, close to the shore and exhibiting almost constant foraging activities. This thesis investigates the distribution and habitat use, both spatially and temporally, of sperm whales (Physeter macrocephalus) within the Kaikoura submarine canyon, New Zealand. The primary aim was to determine which oceanographic variables and bathymetric features influence the sperm whale distribution patterns off Kaikoura.
A theodolite was used to track surfacing and movement of sperm whales from a shore-based station. The accuracy of positions recorded by the theodolite was investigated by comparing theodolite measurements of an object of known position. A calibration technique was then developed as the vertical angle was not accurately determined by the theodolite.
In addition to investigating the distribution of sperm whales, the daily abundance of sperm whales within the Kaikoura submarine canyon was estimated. Distance sampling and mark-resight models showed an average of 4 (SEM = 0.13) individuals present in the study area at any given time. The mark-resight technique using photo-identification was not possible from a shore-based station so a spatio-temporal model was built in order to track the identity of individuals. The model was tested using photo-identification of sperm whales collected from a boat-based station. Results showed that 88% of the modeled identifications corresponded to the photo-identification database.
Sperm whales off Kaikoura were strongly associated with depth, slope and distance from the nearest coast. They were found in waters between 500 m to 1250 m deep and preferred shallower waters in winter. In spring, sperm whales occurred further from the coast, mainly in the Hikurangi Trough, north-east of the shore-based station. Generalized Additive Models (GAM) were used to identify significant oceanographic variables predicting the presence of sperm whales off Kaikoura. Models indicated that sea surface temperature (SST), chlorophylla (Chla) and distance from sea surface temperature fronts were all important parameters in predicting sperm whales presence. Results showed that sperm whales aggregated in the section of the study area with the lowest SST and near SST fronts. This study provides a detailed insight into the use of the Kaikoura submarine canyon by male sperm whales
Extracting density-density correlations from in situ images of atomic quantum gases
We present a complete recipe to extract the density-density correlations and
the static structure factor of a two-dimensional (2D) atomic quantum gas from
in situ imaging. Using images of non-interacting thermal gases, we characterize
and remove the systematic contributions of imaging aberrations to the measured
density-density correlations of atomic samples. We determine the static
structure factor and report results on weakly interacting 2D Bose gases, as
well as strongly interacting gases in a 2D optical lattice. In the strongly
interacting regime, we observe a strong suppression of the static structure
factor at long wavelengths.Comment: 15 pages, 5 figure
Gastrointestinal Tract As Entry Route for Hantavirus Infection
Background: Hantaviruses are zoonotic agents that cause hemorrhagic fevers and
are thought to be transmitted to humans by exposure to aerosolized excreta of
infected rodents. Puumala virus (PUUV) is the predominant endemic hantavirus
in Europe. A large proportion of PUUV-infected patients suffer from
gastrointestinal symptoms of unclear origin. In this study we demonstrate that
PUUV infection can occur via the alimentary tract. Methods: We investigated
susceptibility of the human small intestinal epithelium for PUUV infection and
analyzed the resistance of virions to gastric juice. As model for intestinal
virus translocation we performed infection experiments with human intestinal
Caco-2 monolayers. In animal experiments we infected Syrian hamsters with PUUV
via the intragastric route and tested seroconversion and protective immunity
against subsequent Andes virus challenge. Results: PUUV retained infectivity
in gastric juice at pH >3. The virus invaded Caco-2 monolayers in association
with endosomal antigen EEA1, followed by virus replication and loss of
epithelial barrier function with basolateral virus occurrence. Cellular
disturbance and depletion of the tight junction protein ZO-1 appeared after
prolonged infection, leading to paracellular leakage (leak flux diarrhea).
Moreover, animal experiments led to dose-dependent seroconversion and
protection against lethal Andes virus challenge. Conclusions: We provide
evidence that hantavirus can infect the organism via the alimentary tract and
suggest a novel aspect of hantavirus infection and pathogenesis. Significance:
Hantaviruses are zoonotic pathogens causing severe hemorrhagic fevers
worldwide. They are transmitted to humans by small mammals. To date, these
viruses were thought to infect exclusively through the airborne route by
inhalation of aerosols from infectious animal droppings or by rodent bites. In
our work we could show that the alimentary tract is an alternative path of
infection for hantaviruses, meaning a new association of virus and disease.
These findings have impact on current textbook knowledge and bring many
implications for hantavirus epidemiology and outbreak prevention measures
Serial protein crystallography in an electron microscope
Serial X-ray crystallography at free-electron lasers allows to solve biomolecular structures from sub-micron-sized crystals. However, beam time at these facilities is scarce, and involved sample delivery techniques are required. On the other hand, rotation electron diffraction (MicroED) has shown great potential as an alternative means for protein nano-crystallography. Here, we present a method for serial electron diffraction of protein nanocrystals combining the benefits of both approaches. In a scanning transmission electron microscope, crystals randomly dispersed on a sample grid are automatically mapped, and a diffraction pattern at fixed orientation is recorded from each at a high acquisition rate. Dose fractionation ensures minimal radiation damage effects. We demonstrate the method by solving the structure of granulovirus occlusion bodies and lysozyme to resolutions of 1.55 Å and 1.80 Å, respectively. Our method promises to provide rapid structure determination for many classes of materials with minimal sample consumption, using readily available instrumentation
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