256 research outputs found
Evolution of signalling systems with multiple senders and receivers
Sender–receiver games are simple, tractable models of information transmission. They provide a basic setting for the study the evolution of meaning. It is possible to investigate not only the equilibrium structure of these games but also the dynamics of evolution and learning—with sometimes surprising results. Generalizations of the usual binary game to interactions with multiple senders, multiple receivers or both provide the elements of signalling networks. These can be seen as the loci of information processing, group decisions, and teamwork
Cooling atoms in an optical trap by selective parametric excitation
We demonstrate the possibility of energy-selective removal of cold atoms from
a tight optical trap by means of parametric excitation of the trap vibrational
modes. Taking advantage of the anharmonicity of the trap potential, we
selectively remove the most energetic trapped atoms or excite those at the
bottom of the trap by tuning the parametric modulation frequency. This process,
which had been previously identified as a possible source of heating, also
appears to be a robust way for forcing evaporative cooling in anharmonic traps.Comment: 5 pages, 5 figure
Electronic structure of nuclear-spin-polarization-induced quantum dots
We study a system in which electrons in a two-dimensional electron gas are
confined by a nonhomogeneous nuclear spin polarization. The system consists of
a heterostructure that has non-zero nuclei spins. We show that in this system
electrons can be confined into a dot region through a local nuclear spin
polarization. The nuclear-spin-polarization-induced quantum dot has interesting
properties indicating that electron energy levels are time-dependent because of
the nuclear spin relaxation and diffusion processes. Electron confining
potential is a solution of diffusion equation with relaxation. Experimental
investigations of the time-dependence of electron energy levels will result in
more information about nuclear spin interactions in solids
Randomised controlled trial to evaluate the effect of foot trimming before and after first calving on subsequent lameness episodes and productivity in dairy heifers
The objective of this study was to assess both independent and combined effects of routine foot trimming of heifers at 3 weeks pre-calving and 100 days post calving on the first lactation lameness and lactation productivity. A total of 419 pre-calving dairy heifers were recruited from one heifer rearing operation over a 10-month period. Heifers were randomly allocated into one of four foot trimming regimens; pre-calving foot trim and post-calving lameness score (Group TL), pre-calving lameness score and post-calving foot trim (Group LT), pre-calving foot trim and post-calving foot trim (Group TT), and pre-calving lameness score and post-calving lameness score (Group LL, control group). All heifers were scored for lameness at 24 biweekly time points for 1 year following calving, and first lactation milk production data were collected.
Following calving, 172/419 (41.1%) of heifers became lame during the study (period prevalence), with lameness prevalence at each time-point following calving ranging from 48/392 (12.2%) at 29–42 days post-calving to 4/379 (1.1%) between 295 and 383 days after calving. The effects of the four treatment groups were not significantly different from each other for overall lameness period prevalence, biweekly lameness point prevalence, time to first lameness event, type of foot lesion identified at dry off claw trimming, or the 4% fat corrected 305-day milk yield. However, increased odds lameness was significantly associated with a pre-calving trim alone (P = 0.044) compared to the reference group LL. The odds of heifer lameness were highest between 0 and 6 weeks post-partum, and heifer farm destination was significantly associated with lameness (OR 2.24), suggesting that even at high standard facilities, environment and management systems have more effect on heifer foot health than trimming
Moral courage in the workplace: moving to and from the desire and decision to act
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72135/1/j.1467-8608.2007.00484.x.pd
An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics
For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
Beyond the Shade of the Oak Tree: The Recent Growth of Johannine Studies
The recent growth within Johannine studies has developed as a result of several factors. First, the discovery of the Dead Sea Scrolls led to an appreciation of the Jewishness of John’s origin. Second, new approaches to John’s composition have emerged, followed by a larger set of inquiries as to the Johannine tradition’s relation to parallel traditions. This has been accompanied by a fourth interest: the history of the Johannine situation. Fifth, new literary studies have posed new horizons for interpretation, and sixth, theories continue to abound on the identity of the Beloved Disciple. A seventh development involves new ways of conceiving John’s theological features, leading to an eighth: reconsidering John’s historical features and re-envisioning its historical contributions in new perspective
The Pediatric Cell Atlas: defining the growth phase of human development at single-cell resolution
Single-cell gene expression analyses of mammalian tissues have uncovered profound stage-specific molecular regulatory phenomena that have changed the understanding of unique cell types and signaling pathways critical for lineage determination, morphogenesis, and growth. We discuss here the case for a Pediatric Cell Atlas as part of the Human Cell Atlas consortium to provide single-cell profiles and spatial characterization of gene expression across human tissues and organs. Such data will complement adult and developmentally focused HCA projects to provide a rich cytogenomic framework for understanding not only pediatric health and disease but also environmental and genetic impacts across the human lifespan
Strategies for Controlled Placement of Nanoscale Building Blocks
The capability of placing individual nanoscale building blocks on exact substrate locations in a controlled manner is one of the key requirements to realize future electronic, optical, and magnetic devices and sensors that are composed of such blocks. This article reviews some important advances in the strategies for controlled placement of nanoscale building blocks. In particular, we will overview template assisted placement that utilizes physical, molecular, or electrostatic templates, DNA-programmed assembly, placement using dielectrophoresis, approaches for non-close-packed assembly of spherical particles, and recent development of focused placement schemes including electrostatic funneling, focused placement via molecular gradient patterns, electrodynamic focusing of charged aerosols, and others
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