515 research outputs found
IDENTIFICATION OF LONGLINE FISHING GROUNDS USING MACHINE LEARNING FOR BENTHIC HABITAT IMPACT ASSESMENT
Right-Handed New Physics Remains Strangely Beautiful
Current data on CP violation in B_d -> eta' K_S and B_d -> phi K_S, taken
literally, suggest new physics contributions in b -> s transitions. Despite a
claim to the contrary, we point out that right-handed operators with a single
weak phase can account for both deviations thanks to the two-fold ambiguity in
the extraction of the weak phase from the corresponding CP-asymmetry. This
observation is welcome since large mixing in the right-handed sector is favored
by many GUT models and frameworks which address the flavor puzzle. There are
also interesting correlations with the B_s system which provide a way to test
this scenario in the near future.Comment: 7 pages, 9 figures; published version: added 1 reference and 1
clarificatio
Systematic study of the influence of coherent phonon wave packets on the lasing properties of a quantum dot ensemble
Kohärente Phononen können die Licht-Materie-Wechselwirkung in Halbleiter Nanostrukturen stark ändern. Bei einem Ensemble von Quantenpunkten (QP) als aktivem Lasermedium sind Phononen im Stande, die Laserintensität deutlich zu verstärken oder abzuschwächen. Die Physik des gekoppelten Phonon-Exziton-Licht-Systems wird von verschiedenen Mechanismen dominiert, die im Experiment nicht eindeutig unterschieden werden können, da die komplizierte Probenstruktur zu einem komplexen Verspannungspuls führt, der auf das QP-Ensemble trifft. Hier zeigen wir durch eine umfassende theoretische Studie, wie die Laseremission durch Phononpulse verschiedener Form und QP-Ensembles verschiedener spektraler Verteilung beeinflusst wird. Dies erlaubt einen Einblick in die grundlegenden Wechselspiele des gekoppelten Gesamtsystems. Dadurch können wir zwischen zwei Mechanismen unterschieden: der adiabatischen Verschiebung des Ensembles und dem Schüttel-Effekt. Dies ebnet den Weg zu einer gezielten Kontrolle der Laser Emission durch kohärente Phononen.Coherent phonons can greatly vary light–matter interaction in semiconductor nanostructures placed inside an optical resonator on a picosecond time scale. For an ensemble of quantum dots (QDs) as active laser medium, phonons are able to induce a large enhancement or attenuation of the emission intensity, as has been recently demonstrated. The physics of this coupled phonon–exciton–light system consists of various effects, which in the experiment typically cannot be clearly separated, in particular, due to the complicated sample structure a rather complex strain pulse impinges on the QD ensemble. Here we present a comprehensive theoretical study how the laser emission is affected by phonon pulses of various shapes as well as by ensembles with different spectral distributions of the QDs. This gives insight into the fundamental interaction dynamics of the coupled phonon–exciton–light system, while it allows us to clearly discriminate between two prominent effects: the adiabatic shifting of the ensemble and the shaking effect. This paves the way to a tailored laser emission controlled by phonons.</p
EVALUATION OF THE ELECTORAL PROCESS OF THE 2015 GOVERNORSHIP ELECTION IN LAGOS STATE, NIGERIA
Democracy has gained universal acceptance and periodic eledion is one of basic feature of democracy. Since the advent of the Fourth Republic in 1999, several elections have been conducted at both national, state local government levels. However, the 2015 general elections served as turning points to the entire electoral process in Nigeria due to the higher acceptance of their outcomes and peaceful transition recorded. The paper evaluates electoral process of the 2015 gubernatorial election in Lagos State. The study adopted the historical method by using relevant journal articles, newspaper~ magazines
and reports of eledoral bodies and agencies obtained from the internet. The study was anchored on the Procedural Theory of Democracy. The Content analysis method was
used to gather from the data obtained, issues related to the eledoral process. The units of analysis include intra-party politics/candidates selection, campaign~ voting process and voters' behaviour, declaration of results and matters arising as well as performance
of INEC Findings show that there was little intra-party democracy in the seledion of flag bearers among the two leading parties. Furthermore, the paper found that candidates engage in different kinds of political campaigns such as media tour~ rallies, and social
media posts. The study recommends that political parties should condud proper primary elections and that INEC should improve its performances in future eledions by recruiting and training qualified personnel for proper electoral conduct in order to advance democracy for development in Nigeria
Biscay AGL. An observatory for state of the art operational oceanography at IEO. Derived products, sensor networks and future developments.
Since 1991, shelf and slope waters of the Southern Bay of Biscay are regularly sampled in a monthly hydrographical section north of Santander. From 2003, a deep hydrological standard section was included and on June 2007, an ocean-meteorological buoy was moored at the end of Santander Section (www.boya_agl.st.ieo.es). All of three are part of IEOOS (IEO Observing System). Biscay AGL is one observatory for the EU FixO3 project.
The combination of these resources leads to a powerful tool, Biscay AGL, which is more than the combination of the AGL Buoy and the hydrographical samplings. This tool produces not only time series of several parameters at different time resolutions but also derived products, both real and delayed time. Derived products from this buoy include, annual cycles as well as anomalous values. In particular ones such as air-sea heat fluxes, salinity and water temperatures anomalies, sub inertial currents series, chlorophyll surface series, estimate of the mixed layer depth and wind and currents roses.
Many sensor networks have been deployed to monitor marine environment, and more will follow in the future. Due to the large number of sensor manufacturers, integrating diverse sensors into observation systems is not straightforward. By defining standardized service interfaces it is possible to enable access to sensor networks and archived sensor data that can be discovered and accessed using standard protocols and application programming interfaces. Future developments include the deployment of a full sensor network as well as adding new devices to the Biscay AGL tool in order to achieve deeper knowledge of the ocean
Density of states in d-wave superconductors disordered by extended impurities
The low-energy quasiparticle states of a disordered d-wave superconductor are
investigated theoretically. A class of such states, formed via tunneling
between the Andreev bound states that are localized around extended impurities
(and result from scattering between pair-potential lobes that differ in sign)
is identified. Its (divergent) contribution to the total density of states is
determined by taking advantage of connections with certain one-dimensional
random tight-binding models. The states under discussion should be
distinguished from those associated with nodes in the pair potential.Comment: 5 pages, 1 figur
Microwave conductivity of a d-wave superconductor disordered by extended impurities: a real-space renormalization group approach
Using a real-space renormalization group (RSRG) technique, we compute the
microwave conductivity of a d-wave superconductor disordered by extended
impurities. To do this, we invoke a semiclassical approximation which naturally
accesses the Andreev bound states localized near each impurity. Tunneling
corrections (which are captured using the RSRG) lead to a delocalization of
these quasiparticles and an associated contribution to the microwave
conductivity.Comment: 8 pages, 4 figures. 2 figures added to previous versio
Sensor Networks and derived products at Biscay AGL observatory. State of the art operational oceanography at IEO
Since 1991, shelf and slope waters of the Southern Bay of Biscay are regularly
sampled in a monthly hydrographical section north of Santander, and on June 2007,
an ocean meteorological buoy was moored at the end of Santander Section (www.
boya_agl.st.ieo.es). Both are part of IEOOS (IEO Observing System). Biscay AGL is
one observatory for the EU FixO3 project. Many sensor networks have been deployed
to monitor marine environment, and more will follow in the future. Due to
the large number of sensor technologies, integrating diverse sensors into observation
systems is not straightforward. By defining standardized service interfaces (like
those based on OGC standards) it is possible to enable access to sensor networks
and archived sensor data that can be discovered and accessed using standard protocols
and application programming interfaces, therefore complying with the requirements
of the INSPIRE directive. Future developments include the deployment of a
full sensor network as well as adding new devices to the Biscay AGL tool in order
to achieve a deeper knowledge of the ocean. Biscay AGL is more than the combination
of the AGL Buoy and the hydrographical samplings. This observatory produces
not only time series of several parameters at different time resolutions but also derived
products, both in real and in delayed time. Derived products from this buoy include
annual cycles as well as anomalies of physical and biogeochemical magnitudes
like air-sea heat fluxes, salinity and water temperatures, sub inertial currents, surface
chlorophyll. Different products are derived from in-situ measurements at the AGL
buoy like estimates of the mixed layer depth, wind and currents roses and wave intensity
diagrams
A Nanofiber-Based Optical Conveyor Belt for Cold Atoms
We demonstrate optical transport of cold cesium atoms over millimeter-scale
distances along an optical nanofiber. The atoms are trapped in a
one-dimensional optical lattice formed by a two-color evanescent field
surrounding the nanofiber, far red- and blue-detuned with respect to the atomic
transition. The blue-detuned field is a propagating nanofiber-guided mode while
the red-detuned field is a standing-wave mode which leads to the periodic axial
confinement of the atoms. Here, this standing wave is used for transporting the
atoms along the nanofiber by mutually detuning the two counter-propagating
fields which form the standing wave. The performance and limitations of the
nanofiber-based transport are evaluated and possible applications are
discussed
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