38,773 research outputs found
Wavefunctions and counting formulas for quasiholes of clustered quantum Hall states on a sphere
The quasiholes of the Read-Rezayi clustered quantum Hall states are
considered, for any number of particles and quasiholes on a sphere, and for any
degree k of clustering. A set of trial wavefunctions, that are zero-energy
eigenstates of a k+1-body interaction, and so are symmetric polynomials that
vanish when any k+1 particle coordinates are equal, is obtained explicitly and
proved to be both complete and linearly independent. Formulas for the number of
states are obtained, without the use of (but in agreement with) conformal field
theory, and extended to give the number of states for each angular momentum. An
interesting recursive structure emerges in the states that relates those for k
to those for k-1. It is pointed out that the same numbers of zero-energy states
can be proved to occur in certain one-dimensional models that have recently
been obtained as limits of the two-dimensional k+1-body interaction
Hamiltonians, using results from the combinatorial literature.Comment: 9 pages. v2: minor corrections; additional references; note added on
connection with one-dimensional Hamiltonians of recent interes
Slotted variable camber flap
Variable camber actuator assemblies broaden the range of speeds at which lift to drag performance is maximized for slotted flap wings. Lift is improved over a broader range of cruising speeds by varying wing camber with rotational flap movements that do not introduce wing slots and induced drag. Forward flaps are secured to forward flange links which extended from, and are a part of forward flap linkage assemblies. The forward flaps rotate about flap pivots with their rotational displacement controlled by variable camber actuator assemblies located between the forward flaps and the forward flange links. Rear flaps are held relative to the forward flaps by rear flap linkage assemblies which may act independently from the forward flap linkage assemblies and the variable camber actuator assemblies. Wing camber is varied by rotating the flaps with the variable camber actuator assemblies while the flaps are in a deployed or tucked position. Rotating the flaps in a tucked position does not introduce significant wing surface discontinuities, and reduces aircraft fuel consumption on most flight profiles
Collection Development of HIV/AIDS Information Resources in American Libraries
HIV/AIDS remains an incurable epidemic in the United States that disproportionately affects men who have sex with men (MSM) and African Americans. Library and information science (LIS) professionals can play a vital role in keeping these higher risk groups informed about preventing HIV/AIDS and living with the disease, through a variety of current information resources that addresses their specific questions. This paper reviews collection development policies proposed by LIS professionals and library agencies since the late 1980s, and evaluates how such policies took higher-risk user groups into consideration. The findings of this paper are that collection development policies have become more attentive to higher-risk user groups but that LIS research trends are now beginning to focus more on the HIV/AIDS epidemic in developing countries, which is to the detriment of Americans who still need up-to-date materials on the disease
q,k-generalized gamma and beta functions
We introduce the q,k-generalized Pochhammer symbol. We construct
and , the q,k-generalized gamma and beta fuctions, and
show that they satisfy properties that generalize those satisfied by the
classical gamma and beta functions. Moreover, we provide integral
representations for and Comment: 17 page
Joint Resource Partitioning and Offloading in Heterogeneous Cellular Networks
In heterogeneous cellular networks (HCNs), it is desirable to offload mobile
users to small cells, which are typically significantly less congested than the
macrocells. To achieve sufficient load balancing, the offloaded users often
have much lower SINR than they would on the macrocell. This SINR degradation
can be partially alleviated through interference avoidance, for example time or
frequency resource partitioning, whereby the macrocell turns off in some
fraction of such resources. Naturally, the optimal offloading strategy is
tightly coupled with resource partitioning; the optimal amount of which in turn
depends on how many users have been offloaded. In this paper, we propose a
general and tractable framework for modeling and analyzing joint resource
partitioning and offloading in a two-tier cellular network. With it, we are
able to derive the downlink rate distribution over the entire network, and an
optimal strategy for joint resource partitioning and offloading. We show that
load balancing, by itself, is insufficient, and resource partitioning is
required in conjunction with offloading to improve the rate of cell edge users
in co-channel heterogeneous networks
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