1,357 research outputs found
Shape computations without compositions
Parametric CAD supports design explorations through generative methods which compose and transform geometric elements. This paper argues that elementary shape computations do not always correspond to valid compositional shape structures. In many design cases generative rules correspond to compositional structures, but for relatively simple shapes and rules it is not always possible to assign a corresponding compositional structure of parts which account for all operations of the computation. This problem is brought into strong relief when design processes generate multiple compositions according to purpose, such as product structure, assembly, manufacture, etc. Is it possible to specify shape computations which generate just these compositions of parts or are there additional emergent shapes and features? In parallel, combining two compositions would require the associated combined computations to yield a valid composition. Simple examples are presented which throw light on the issues in integrating different product descriptions (i.e. compositions) within parametric CAD
Basic principles of postgrowth annealing of CdTe:Cl ingot to obtain semi-insulating crystals
The process of annealing of a CdTe:Cl ingot during its cooling after growth
was studied. The annealing was performed in two stages: a high-temperature
stage, with an approximate equality of chlorine and cadmium vacancy
concentrations established at the thermodynamic equilibrium between the crystal
and vapors of volatile components, and a low-temperature stage, with charged
defects interacting to form neutral associations. The chlorine concentrations
necessary to obtain semi-insulating crystals were determined for various ingot
cooling rates in the high temperature stage. The dependence of the chlorine
concentration [Cl+Te] in the ingot on the temperature of annealing in the
high-temperature stage was found. The carrier lifetimes and drift mobilities
were obtained in relation to the temperature and cadmium vapor pressure in the
postgrowth annealing of the ingot.Comment: 6 pages, 6 figure
Simulation of associative learning with the replaced elements model
Associative learning theories can be categorised according to whether they treat the representation of stimulus compounds in an elemental or configural manner. Since it is clear that a simple elemental approach to stimulus representation is inadequate there have been several attempts to produce more elaborate elemental models. One recent approach, the Replaced Elements Model (Wagner, 2003), reproduces many results that have until recently been uniquely predicted by Pearce’s Configural Theory (Pearce, 1994). Although it is possible to simulate the Replaced Elements Model using “standard” simulation programs the generation of the correct stimulus representation is complex. The current paper describes a method for simulation of the Replaced Elements Model and presents the results of two example simulations that show differential predictions of Replaced Elements and Pearce’s Configural Theor
Common pitfalls, and how to avoid them, in child and adolescent psychopharmacology: Part I
\ua9 The Author(s) 2024.As Faculty of the British Association for Psychopharmacology course on child and adolescent psychopharmacology, we present here what we deem are the most common pitfalls, and how to avoid them, in child and adolescent psychopharmacology. In this paper, we specifically addressed common pitfalls in the pharmacological treatment of attention-deficit/hyperactivity disorder, anxiety, bipolar disorder, depression, obsessive-compulsive disorder and related disorders, and tic disorder. Pitfalls in the treatment of other disorders are addressed in a separate paper (part II)
Common pitfalls, and how to avoid them, in child and adolescent psychopharmacology: Part II
\ua9 The Author(s) 2024.As Faculty of the British Association for Psychopharmacology course on child and adolescent psychopharmacology, we present here what we deem are the most common pitfalls, and how to avoid them, in child and adolescent psychopharmacology. In this paper, we specifically addressed common pitfalls in the pharmacological treatment of autism and intellectual disability, eating disorders, neuropsychiatric correlates of epilepsy, and psychosis. Pitfalls in relation to the treatment of other disorders are addressed in a separate paper (Part I)
Laser wakefield acceleration with mid-IR laser pulses
We report on the first results of laser plasma wakefield acceleration driven
by ultrashort mid-infrared laser pulses (\lambda= 3.9 \mu m, 100 fs, 0.25 TW),
which enable near- and above-critical density interactions with
moderate-density gas jets. Relativistic electron acceleration up to ~12 MeV
occurs when the jet width exceeds the threshold scale length for relativistic
self-focusing. We present scaling trends in the accelerated beam profiles,
charge and spectra, which are supported by particle-in-cell simulations and
time-resolved images of the interaction. For similarly scaled conditions, we
observe significant increases in accelerated charge compared to previous
experiments with near-infrared (\lambda=800 nm) pulses
Influence of extended dynamics on phase transitions in a driven lattice gas
Monte Carlo simulations and dynamical mean-field approximations are performed
to study the phase transition in a driven lattice gas with nearest-neighbor
exclusion on a square lattice. A slight extension of the microscopic dynamics
with allowing the next-nearest-neighbor hops results in dramatic changes.
Instead of the phase separation into high- and low-density regions in the
stationary state the system exhibits a continuous transition belonging to the
Ising universality class for any driving. The relevant features of phase
diagram are reproduced by an improved mean-field analysis.Comment: 3 pages, 3 figure
Chromatin accessibility dynamics across C. elegans development and ageing
An essential step for understanding the transcriptional circuits that control development and physiology is the global identification and characterization of regulatory elements. Here we present the first map of regulatory elements across the development and ageing of an animal, identifying 42,245 elements accessible in at least one C. elegans stage. Based on nuclear transcription profiles, we define 15,714 protein-coding promoters and 19,231 putative enhancers, and find that both types of element can drive orientation-independent transcription. Additionally, more than 1000 promoters produce transcripts antisense to protein coding genes, suggesting involvement in a widespread regulatory mechanism. We find that the accessibility of most elements changes during development and/or ageing and that patterns of accessibility change are linked to specific developmental or physiological processes. The map and characterization of regulatory elements across C. elegans life provides a platform for understanding how transcription controls development and ageing
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