5,411 research outputs found
Distinct roles of transcription factors EGL-46 and DAF-19 in specifying the functionality of a polycystin-expressing sensory neuron necessary for C. elegans male vulva location behavior
Caenorhabditis elegans polycystins LOV-1 and PKD-2 are expressed in the male-specific HOB neuron, and are necessary for sensation of the hermaphrodite vulva during mating. We demonstrate that male vulva location behavior and expression of lov-1 and pkd-2 in the ciliated sensory neuron HOB require the activities of transcription factor EGL-46 and to some extent also EGL-44. This EGL-46- regulated program is specific to HOB and is distinct from a general ciliogenic pathway functioning in all ciliated neurons. The ciliogenic pathway regulator DAF-19 affects downstream components of the HOB-specific program indirectly and is independent of EGL-46 activity. The sensory function of HOB requires the combined action of these two distinct regulatory pathways
Liquid-liquid interfacial tension of electrolyte solutions
It is theoretically shown that the excess liquid-liquid interfacial tension
between two electrolyte solutions as a function of the ionic strength I behaves
asymptotically as O(- I^0.5) for small I and as O(+- I) for large I. The former
regime is dominated by the electrostatic potential due to an unequal
partitioning of ions between the two liquids whereas the latter regime is
related to a finite interfacial thickness. The crossover between the two
asymptotic regimes depends sensitively on material parameters suggesting that,
depending on the actual system under investigation, the experimentally
accessible range of ionic strengths can correspond to either the small or the
large ionic strength regime. In the limiting case of a liquid-gas surface where
ion partitioning is absent, the image chage interaction can dominate the
surface tension for small ionic strength I such that an Onsager-Samaras
limiting law O(- I ln(I)) is expected. The proposed picture is consistent with
more elaborate models and published measurements.Comment: Accepted for publication in Physical Review Letter
Ion association in low-polarity solvents: comparisons between theory, simulation, and experiment
The association of ions in electrolyte solutions at very low concentration
and low temperature is studied using computer simulations and quasi-chemical
ion-pairing theory. The specific case of the restricted primitive model
(charged hard spheres) is considered. Specialised simulation techniques are
employed that lead to efficient sampling of the arrangements and distributions
of clusters and free ions, even at conditions corresponding to nanomolar
solutions of simple salts in solvents with dielectric constants in the range
5-10, as used in recent experimental work on charged-colloid sus- pensions. A
direct comparison is effected between theory and simulation using a variety of
clustering criteria and theoretical approximations. It is shown that
conventional distance-based cluster criteria can give erroneous results. A
reliable set of theoretical and simulation estimators for the degree of
association is proposed. The ion-pairing theory is then compared to
experimental results for salt solutions in low-polarity solvents. The agreement
is excellent, and on this basis some calculations are made for the screening
lengths which will figure in the treatment of colloid-colloid interactions in
such solutions. The accord with available experimental results is complete
European Airport Concessions: Retail Strategies to Improve Commercial Revenue from Leisure Travelers
Aeronautical revenue from landing and handling charges to carriers is falling significantly below 60% of total revenue and will not persist as the main source of income for airports. Airports in Europe cannot continue to rely on profits from airlines; operating companies need to improve the competitiveness through commercial income from different traveler types. The purpose of this multiple case study was to understand the elements of successful sales strategies by concessionaires (retailers) at the metropolitan airport system of Zurich and Basel in hopes of improving the nonaeronautical revenue from leisure travelers, a price-sensitive customer segment. The conceptual framework was corporate strategic planning with the underlying concept of sustainable business operations. Semistructured interviews included 9 executives and senior managers of concessions and retail operations at Zurich International and Basel EuroAirport, and covered major themes such as managing the shopping experience of passengers as well as collaboration between concessionaires, airports, and airlines. The key findings, which emerged from an inductive analysis of the data, were that the identification of personalized offerings and the inclusion of individual travelers\u27 needs are required to ensure a flexible approach by each airport and shop location throughout the terminal. The collected data contained indicators for holistic and targeted concepts by retail concessions in cooperation with airport stakeholders. Social implications include sustainable retail strategies by promoting value adding products and services, improving the passenger\u27s travel experience, and ensuring the profitability of concessionaires in a changing aviation market
Modeling the optical/UV polarization while flying around the tilted outflows of NGC 1068
Recent modeling of multi-waveband spectroscopic and maser observations
suggests that the ionized outflows in the nuclear region of the archetypal
Seyfert-2 galaxy NGC 1068 are inclined with respect to the vertical axis of the
obscuring torus. Based on this suggestion, we build a complex reprocessing
model of NGC 1068 for the optical/UV band. We apply the radiative transfer code
STOKES to compute polarization spectra and images. The effects of electron and
dust scattering and the radiative coupling occurring in the inner regions of
the multi-component object are taken into account and evaluated at different
polar and azimuthal viewing angles. The observed type-1/type-2 polarization
dichotomy of active galactic nuclei is reproduced. At the assumed observer's
inclination toward NGC 1068, the polarization is dominated by scattering in the
polar outflows and therefore it indicates their tilting angle with respect to
the torus axis. While a detailed analysis of our model results is still in
progress, we briefly discuss how they relate to existing polarization
observations of NGC 1068.Comment: To appear in the proceedings of the meeting "The Central Kiloparsec
in Galactic Nuclei" held in Bad Honnef (Germany) from August 29th to
September 2nd 201
Reachability-based impact as a measure for insiderness
Insider threats pose a difficult problem for many organisations. While organisations in principle would like to judge the risk posed by a specific insider threat, this is in general not possible. This limitation is caused partly by the lack of models for human behaviour, partly by restrictions on how much and what may be monitored, and by our inability to identify relevant features in large amounts of logged data. To overcome this, the notion of insiderness has been proposed, which measures the degree of access an actor has to a certain resource. We extend this notion with the concept of impact of an insider, and present different realisations of impact. The suggested approach results in readily usable techniques that allow to get a quick overview of potential insider threats based on locations and assets reachable by employees. We present several variations ranging from pure reachability to potential damage to assets causable by an insider
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