42,519 research outputs found
Lifting defects for nonstable K_0-theory of exchange rings and C*-algebras
The assignment (nonstable K_0-theory), that to a ring R associates the monoid
V(R) of Murray-von Neumann equivalence classes of idempotent infinite matrices
with only finitely nonzero entries over R, extends naturally to a functor. We
prove the following lifting properties of that functor: (1) There is no functor
F, from simplicial monoids with order-unit with normalized positive
homomorphisms to exchange rings, such that VF is equivalent to the identity.
(2) There is no functor F, from simplicial monoids with order-unit with
normalized positive embeddings to C*-algebras of real rank 0 (resp., von
Neumann regular rings), such that VF is equivalent to the identity. (3) There
is a {0,1}^3-indexed commutative diagram D of simplicial monoids that can be
lifted, with respect to the functor V, by exchange rings and by C*-algebras of
real rank 1, but not by semiprimitive exchange rings, thus neither by regular
rings nor by C*-algebras of real rank 0. By using categorical tools from an
earlier paper (larders, lifters, CLL), we deduce that there exists a unital
exchange ring of cardinality aleph three (resp., an aleph three-separable
unital C*-algebra of real rank 1) R, with stable rank 1 and index of nilpotence
2, such that V(R) is the positive cone of a dimension group and V(R) is not
isomorphic to V(B) for any ring B which is either a C*-algebra of real rank 0
or a regular ring.Comment: 34 pages. Algebras and Representation Theory, to appea
Recognizing Emotions in a Foreign Language
Expressions of basic emotions (joy, sadness, anger, fear, disgust) can be recognized pan-culturally from the face and it is assumed that these emotions can be recognized from a speaker's voice, regardless of an individual's culture or linguistic ability. Here, we compared how monolingual speakers of Argentine Spanish recognize basic emotions from pseudo-utterances ("nonsense speech") produced in their native language and in three foreign languages (English, German, Arabic). Results indicated that vocal expressions of basic emotions could be decoded in each language condition at accuracy levels exceeding chance, although Spanish listeners performed significantly better overall in their native language ("in-group advantage"). Our findings argue that the ability to understand vocally-expressed emotions in speech is partly independent of linguistic ability and involves universal principles, although this ability is also shaped by linguistic and cultural variables
Poverty reduction through alternative livelihoods in Botswana\'s desert margins
Despite rapid economic growth recorded in the last decades following independence in 1966, poverty is still rampant especially in the rural areas of Botswana. Poverty reduction has been on the agenda for many years and poverty reduction strategy has mainly concentrated on the improvement of both agricultural production and
productivity since the majority of the population residing in the rural areas depend mainly on agriculture for their livelihoods. The findings of this study indicate that there are other livelihood options available in the rural areas which might help government in its efforts to reduce poverty. According to the study, there are several livelihood options available in the desert margins of Botswana, but communities fail to exploit these due to a number of constraints such as poor access to financial credit, lack of awareness of potential income earners such as eco-tourism, insufficient knowledge and technical expertise. Hence government efforts aimed at improving access to financial credit and creation of awareness on potential income earners apart from agriculture are likely to succeed in reducing poverty in the rural areas. South African Journal of Agricultural Extension Vol. 35 (1) 2006: pp. 37-5
Activation-induced deoxycytidine deaminase (AID) co-transcriptional scanning at single-molecule resolution
Activation-induced deoxycytidine deaminase (AID) generates antibody diversity in B cells by initiating somatic hypermutation (SHM) and class-switch recombination (CSR) during transcription of immunoglobulin variable (IgV) and switch region (IgS) DNA. Using single-molecule FRET, we show that AID binds to transcribed dsDNA and translocates unidirectionally in concert with RNA polymerase (RNAP) on moving transcription bubbles, while increasing the fraction of stalled bubbles. AID scans randomly when constrained in an 8 nt model bubble. When unconstrained on single-stranded (ss) DNA, AID moves in random bidirectional short slides/hops over the entire molecule while remaining bound for ~5 min. Our analysis distinguishes dynamic scanning from static ssDNA creasing. That AID alone can track along with RNAP during transcription and scan within stalled transcription bubbles suggests a mechanism by which AID can initiate SHM and CSR when properly regulated, yet when unregulated can access non-Ig genes and cause cancer
Velocity of sound in a Bose-Einstein condensate in the presence of an optical lattice and transverse confinement
We study the effect of the transverse degrees of freedom on the velocity of
sound in a Bose-Einstein condensate immersed in a one-dimensional optical
lattice and radially confined by a harmonic trap. We compare the results of
full three-dimensional calculations with those of an effective 1D model based
on the equation of state of the condensate. The perfect agreement between the
two approaches is demonstrated for several optical lattice depths and
throughout the full crossover from the 1D mean-field to the Thomas Fermi regime
in the radial direction.Comment: final versio
Simultaneous Orthogonal Planarity
We introduce and study the problem: Given planar
graphs each with maximum degree 4 and the same vertex set, do they admit an
OrthoSEFE, that is, is there an assignment of the vertices to grid points and
of the edges to paths on the grid such that the same edges in distinct graphs
are assigned the same path and such that the assignment induces a planar
orthogonal drawing of each of the graphs?
We show that the problem is NP-complete for even if the shared
graph is a Hamiltonian cycle and has sunflower intersection and for
even if the shared graph consists of a cycle and of isolated vertices. Whereas
the problem is polynomial-time solvable for when the union graph has
maximum degree five and the shared graph is biconnected. Further, when the
shared graph is biconnected and has sunflower intersection, we show that every
positive instance has an OrthoSEFE with at most three bends per edge.Comment: Appears in the Proceedings of the 24th International Symposium on
Graph Drawing and Network Visualization (GD 2016
SARS-CoV-2 Transmission Route in Wastewater and Possible Solutions
In the view of present SARS-CoV-2 pandemic a study on the presence of this novel virus in wastewater treatment facilities is proposed. Other coronavirus species are known to survive in wastewater for days to weeks. Present data also shows that SARS-CoV-2 can be present in waste product generated by infected humans. This generated waste can be source of this virus to wastewater stream and being an enveloped virus can survive for longer period, which can be aerosolized and act as secondary transmission source. Here we propose this pathway of transmission should be rigorously studied, especially in countries like India, where minimum hygiene and sanitation can be tough to achieve because of high population density. We further propose to look into different disinfection methods, which can be most useful to deactivate this lethal viru
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