547 research outputs found
N=2 central charge superspace and a minimal supergravity multiplet
We extend the notion of central charge superspace to the case of local
supersymmetry. Gauged central charge transformations are identified as
diffeomorphisms at the same footing as space-time diffeomorphisms and local
supersymmetry transformations. Given the general structure we then proceed to
the description of a particular vector-tensor supergravity multiplet of 24+24
components, identified by means of rather radical constraints
An overview of new supersymmetric gauge theories with 2-form gauge potentials
An overview of new 4d supersymmetric gauge theories with 2-form gauge
potentials constructed by various authors during the past five years is given.
The key role of three particular types of interaction vertices is emphasized.
These vertices are used to develop a connecting perspective on the new models
and to distinguish between them. One example is presented in detail to
illustrate characteristic features of the models. A new result on couplings of
2-form gauge potentials to Chern-Simons forms is presented.Comment: 11 pages; to appear in the proceedings of NATO ARW "Noncommutative
structures in mathematics and physics" (Kiev 09/00); table in section 3
correcte
Superform formulation for vector-tensor multiplets in conformal supergravity
The recent papers arXiv:1110.0971 and arXiv:1201.5431 have provided a
superfield description for vector-tensor multiplets and their Chern-Simons
couplings in 4D N = 2 conformal supergravity. Here we develop a superform
formulation for these theories. Furthermore an alternative means of gauging the
central charge is given, making use of a deformed vector multiplet, which may
be thought of as a variant vector-tensor multiplet. Its Chern-Simons couplings
to additional vector multiplets are also constructed. This multiplet together
with its Chern-Simons couplings are new results not considered by de Wit et al.
in hep-th/9710212.Comment: 28 pages. V2: Typos corrected and references updated; V3: References
updated and typo correcte
Self-image threat decreases stereotyping: The role of motivation toward closure.
Some prior research indicated that self-image threat may lead people to stereotyping and prejudiced evaluations of others. Other studies found that self-image threat may promote less stereotypical thinking and unprejudiced behavior. In a series of three studies, we demonstrate that self-image threat may lead to either more or less stereotypical perception of the outgroup depending on the level of the individuals` motivation toward closure (NFC). The results reveal that when individuals high (vs. low) in NFC perceived a member of an outgroup, they are less likely to use stereotypical traits if their self-image had been threatened by negative feedback (Study 1) or if they had imagined an example of their own immoral activity (Studies 2 and 3). Moreover, our results demonstrate that the fear of invalidity resulting from self-image threat induction is responsible for the foregoing effects (Study 3). These results are discussed in light of theories of motivational readiness and lay epistemics
Nambu mass hierarchies in strings
We show that a recent proposal by Nambu to generate a hierarchy among Yukawa
couplings in the standard model may be easily implemented in superstring
models. In such models, two of the main ingredients of the Nambu proposal find
a natural explanation: minimising with respect to the Yukawas amounts to a
minimisation with respect to the underlying moduli fields and a constraint on
the Yukawas of the type of the Veltman condition may be attributed to the
relaxation process to a phenomenologically viable string vacuum.Comment: 12 pages, LATEX, LPTHE 94/3
The linear multiplet and ectoplasm
In the framework of the superconformal tensor calculus for 4D N=2
supergravity, locally supersymmetric actions are often constructed using the
linear multiplet. We provide a superform formulation for the linear multiplet
and derive the corresponding action functional using the ectoplasm method (also
known as the superform approach to the construction of supersymmetric
invariants). We propose a new locally supersymmetric action which makes use of
a deformed linear multiplet. The novel feature of this multiplet is that it
corresponds to the case of a gauged central charge using a one-form potential
not annihilated by the central charge (unlike the standard N=2 vector
multiplet). Such a gauge one-form can be chosen to describe a variant nonlinear
vector-tensor multiplet. As a byproduct of our construction, we also find a
variant realization of the tensor multiplet in supergravity where one of the
auxiliaries is replaced by the field strength of a gauge three-form.Comment: 31 pages; v3: minor corrections and typos fixed, version to appear in
JHE
Effect of egg turning and incubation time on carbonic anhydrase gene expression in the blastoderm of the Japanese quail (Coturnix c. japonica)
(1) The gene expression of carbonic anhydrase, a key enzyme for the production sub-embryonic fluid (SEF), was assessed in turned and unturned eggs of the Japanese quail. The plasma membrane-associated isoforms CA IV, CAIX, CA XII, CA XIV, and the cytoplasmic isoform CA II, were
investigated in the extra-embryonic tissue of the blastoderm and in embryonic blood.
(2) Eggs were incubated at 37.6C, c. 60% R.H., and turned hourly (90 ) or left unturned. From 48 to 96 hours of incubation mRNA was extracted from blastoderm tissue, reverse-transcribed to cDNA and quantified by real-time qPCR using gene-specific primers. Blood collected at 96h was processed identically.
(3) Blastoderm CAIV gene expression increased with the period of incubation only in turned eggs, with maxima at 84 and 96h of incubation. Only very low levels were found in blood.
(4) Blastoderm CA II gene expression was greatest at 48 and 54h of incubation, subsequently declining to much lower levels and una ected by turning. Blood CA II gene expression was about 25-fold greater than that in the blastoderm.
(5) The expression of CA IX in the blastoderm was the highest of all isoforms, yet unaffected by turning.
CA XII did not amplify and CA XIV was present at unquantifiable low levels.
(6) It is concluded that solely gene expression for CA IV is sensitive to egg turning, and that increased CA IV gene expression could account for the additional SEF mass found at 84-96h of incubation.
in embryos of turned eggs
Correlation Functions of Conserved Currents in N = 2 Superconformal Theory
Using a manifestly supersymmetric formalism, we determine the general
structure of two- and three- point functions of the supercurrent and the
flavour current of N = 2 superconformal field theories. We also express them in
terms of N = 1 superfields and compare to the generic N = 1 correlation
functions. A general discussion of the N = 2 supercurrent superfield and the
multiplet of anomalies and their definition as derivatives with respect to the
supergravity prepotentials is also included.Comment: 43 pages, latex, no figures, v.2: section 4.2 extende
Calibration procedures and first data set of Southern Ocean chlorophyll a profiles collected by elephant seals equipped with a newly developed CTD-fluorescence tags
In-situ observation of the marine environment has traditionally relied on ship-based platforms. The obvious consequence is that physical and biogeochemical properties have been dramatically undersampled, especially in the remote Southern Ocean (SO). The difficulty in obtaining in situ data represents the major limitations to our understanding, and interpretation of the coupling between physical forcing and the biogeochemical response. Southern elephant seals (Mirounga leonina) equipped with a new generation of oceanographic sensors can measure ocean structure in regions and seasons rarely observed with traditional oceanographic platforms. Over the last few years, seals have allowed for a considerable increase in temperature and salinity profiles from the SO. However we were still lacking information on the spatio-temporal variation of phytoplankton concentration. This information is critical to assess how the biological productivity of the SO, with direct consequences on the amount of CO2 "fixed" by the biological pump, will respond to global warming. In this research program, we use an innovative sampling fluorescence approach to quantify phytoplankton concentration at sea. For the first time, a low energy consumption fluorometer was added to Argos CTD-SRDL tags, and these novel instruments were deployed on 27 southern elephant seals between 25 December 2007 and the 4 February 2011. As many as 3388 fluorescence profiles associated with temperature and salinity measurements were thereby collected from a vast sector of the Southern Indian Ocean. This paper address the calibration issue of the fluorometer before being deployed on elephant seals and present the first results obtained for the Indian Sector of the Southern Ocean.This in situ system is implemented in synergy with satellite ocean colour radiometry. Satellite-derived data is limited to the surface layer and is restricted over the SO by extensive cloud cover. However, with the addition of these new tags, we're able to assess the 3 dimension distribution of phytoplankton concentration by foraging southern elephant seals. This approach reveals that for the Indian sector of the SO, the surface chlorophyll a (chl a) concentrations provided by MODIS were underestimated by a factor of the order of 2â3 compared to in situ measurements. The scientific outcomes of this program include an improved understanding of both the present state and variability in ocean biology, and the accompanying biogeochemistry, as well as the delivery of real-time and open-access data to scientists
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