Nilpotent invariants in N=4 SYM

It is shown that there are no nilpotent invariants in N=4 analytic superspace for $n\leq4$ points. It is argued that there is (at least) one such invariant for n=5 points which is not invariant under U(1)_Y. The consequences of these results are that the n=2 and 3 point correlation functions of the N=4 gauge-invariant operators which correspond to KK multiplets in AdS supergravity are given exactly by their tree level expressions, the 4 point correlation functions of such operators are invariant under U(1)_Y and correlation functions with $n\geq 4$ points have non-trivial dependence on the Yang-Mills coupling constant.Comment: 9 page

Experimental characterization of a supercapacitor-based electrical torque-boost system for downsized ICE vehicles

The need to improve fuel economy and reduce the emission of CO2 and other harmful pollution from internal-combustion-engine vehicles has led to engine downsizing. However, downsized turbocharged engines exhibit a relatively low torque capability at low engine speeds. To overcome this problem, an electrical torque boost may be employed while accelerating and changing gear and to facilitate energy recovery during regenerative braking. This paper describes the operational requirements of a supercapacitor-based torque-boost system, outlines the design and sizing of the electrical drive-train components, and presents experimental characterization of a demonstrator system

Four-point functions in N=2 superconformal field theories

Four-point correlation functions of hypermultiplet bilinear composites are analysed in N=2 superconformal field theory using the superconformal Ward identities and the analyticity properties of the composite operator superfields. It is shown that the complete amplitude is determined by a single arbitrary function of the two conformal cross-ratios of the space-time variables.Comment: 36 pp LaTeX2e, uses amsfonts, amssymb. Some references adde

Partial non-renormalisation of the stress-tensor four-point function in N=4 SYM and AdS/CFT

We show that, although the correlator of four stress-tensor multiplets in N=4 SYM is known to have radiative corrections, certain linear combinations of its components are protected from perturbative renormalisation and remain at their free-field values. This result is valid for weak as well as for strong coupling and for any gauge group. Our argument uses Intriligator's insertion formula, and includes a proof that the possible contact term contributions cannot change the form of the amplitudes. Combining this new non-renormalisation theorem with Maldacena's conjecture allows us to make a prediction for the structure of the corresponding correlator in AdS supergravity. This is verified by first considerably simplifying the strong coupling expression obtained by recent supergravity calculations, and then showing that it does indeed exhibit the expected structure.Comment: 21 pages, no figure

A Comparative Study of Scholastic Achievement between Day and Dormitory High School Students in Ankara, Turkey

The primary purpose of this study was to compare the scholastic achievement of dormitory students and day students after both groups entered Ankara American High School

Regarding themselves as permanently settled : An Ethnohistory of Cherokee Hyper-Displacement

“Regarding themselves as permanently settled” analyzes displacement and resettlement of four Cherokee regions and sets of communities during the first few decades of the nineteenth century. Instead of parsing out various Cherokee removal episodes of the period, this dissertation moves across time and space to foreground the human experiences as expressed by the displaced Cherokees themselves. Instead of utilizing a framework of Euro-American removal tactics to compartmentalize, marginalize and silence tribal agency throughout displacement episodes, what were the social elements of individual and collective networks utilized to navigate removal, and subsequent responses to newly constituted social networks when forming new communities in a post-displacement setting. I foreground existing tribal culturally grounded manifestations of self-determination to understand the importance of family and kin during times of isolation and stress, a process I refer to as hyper-displacement. Additionally, this dissertation emphasizes the uniquely centered Cherokee cultural components of tohi (balance, or walking the correct way, the open way), and osi (life in a good state) within larger discourses surrounding the normalization of violence experienced by indigenous populations throughout the early establishment of federal Indian policy.My main data-sets were collections of sworn affidavits, depositions, memorials, and spoliation claims presented by individual Cherokees over a twenty-year period. Most often these data-sets were presented by Cherokees seeking monetary recompense of their removal from homes and farms to the very federal agents who had legislatively, economically and forcibly removed them. The application of an ethnohistorical ethnographic approach to these archival materials, what I call archival participant observation, emphasizes new perspectives to analyze Cherokee towns not necessarily just predicated on a specific location, but as organically interconnected networks of mutual aid and fellowship. While this dissertation is grounded in a nineteenth century Cherokee perspective of displacement and post-displacement community construction, it provides insight to understand the wider implications of how individuals and communities navigate displacement. This dissertation illustrates that sometimes all we have are our social and familial networks, and the lengths people centralize them following displacement

BRST quantization of matrix models with constraints and two-dimensional Yang-Mills theory on the cylinder

BRST quantization of the one-dimensional constrained matrix model which describes two-dimensional Yang-Mills theory on the cylinder is performed. Classical and quantum BRST generators and BRST-invariant hamiltonians are constructed. Evolution operator is expressed in terms of BRST path integral. Advantages of the BRST quantization over the reduced phase space approach leading to the theory of $N$ free fermions are discussed.Comment: 8 page

Holonomy groups and W-symmetries

Irreducible sigma models, i.e. those for which the partition function does not factorise, are defined on Riemannian spaces with irreducible holonomy groups. These special geometries are characterised by the existence of covariantly constant forms which in turn give rise to symmetries of the supersymmetric sigma model actions. The Poisson bracket algebra of the corresponding currents is a W-algebra. Extended supersymmetries arise as special cases.Comment: pages 2

A Reference-Free Algorithm for Computational Normalization of Shotgun Sequencing Data

Deep shotgun sequencing and analysis of genomes, transcriptomes, amplified single-cell genomes, and metagenomes has enabled investigation of a wide range of organisms and ecosystems. However, sampling variation in short-read data sets and high sequencing error rates of modern sequencers present many new computational challenges in data interpretation. These challenges have led to the development of new classes of mapping tools and {\em de novo} assemblers. These algorithms are challenged by the continued improvement in sequencing throughput. We here describe digital normalization, a single-pass computational algorithm that systematizes coverage in shotgun sequencing data sets, thereby decreasing sampling variation, discarding redundant data, and removing the majority of errors. Digital normalization substantially reduces the size of shotgun data sets and decreases the memory and time requirements for {\em de novo} sequence assembly, all without significantly impacting content of the generated contigs. We apply digital normalization to the assembly of microbial genomic data, amplified single-cell genomic data, and transcriptomic data. Our implementation is freely available for use and modification