Studies Directed Towards the Preparation of Probes for the Photoaffinity Labelling of Gibberellin Receptors

2011 ◽  
Vol 64 (4) ◽  
pp. 471 ◽  
Author(s):  
James R. Crow ◽  
Peter M. Chandler ◽  
Lewis N. Mander
Keyword(s):  
Insertion Reaction ◽  
Lower Face ◽  
Barley Endosperm ◽  
Model Studies ◽  
Receptor Sites ◽  
Diazo Ketone ◽  
Wide Range ◽  
Photoaffinity Probes ◽  
Rhodium Acetate ◽  
Gibberellin Derivatives

Model studies for the preparation of photoaffinity probes designed to explore the nature of gibberellin receptor sites have provided a wide range of gibberellin derivatives that should afford useful scaffolds incorporating auxiliary groups attached to C-2 and C-12. Methodology features the stereocontrolled opening of 2β,3β-epoxy gibberellins by attack on the lower face at C-2, while functionalization of C-12 was effected by the rhodium acetate-catalyzed CH insertion reaction of a 17-diazo ketone. Compounds were screened for bioactivity in growth and barley endosperm-based bioassays.

scholarly journals A Model for Analysing the Collective Dynamic Behaviour and Characterising the Exploitation of Population-Based Algorithms

2014 ◽  
Vol 22 (1) ◽  
pp. 159-188 ◽  
Author(s):  
Mikdam Turkey ◽  
Riccardo Poli
Keyword(s):  
Population Dynamics ◽  
Dynamic Behaviour ◽  
Fitness Landscape ◽  
Population Based ◽  
Levels Of Abstraction ◽  
Collective Dynamic ◽  
Model Studies ◽  
Proposed Model ◽  
Wide Range ◽  
Multiple Levels

Several previous studies have focused on modelling and analysing the collective dynamic behaviour of population-based algorithms. However, an empirical approach for identifying and characterising such a behaviour is surprisingly lacking. In this paper, we present a new model to capture this collective behaviour, and to extract and quantify features associated with it. The proposed model studies the topological distribution of an algorithm's activity from both a genotypic and a phenotypic perspective, and represents population dynamics using multiple levels of abstraction. The model can have different instantiations. Here it has been implemented using a modified version of self-organising maps. These are used to represent and track the population motion in the fitness landscape as the algorithm operates on solving a problem. Based on this model, we developed a set of features that characterise the population's collective dynamic behaviour. By analysing them and revealing their dependency on fitness distributions, we were then able to define an indicator of the exploitation behaviour of an algorithm. This is an entropy-based measure that assesses the dependency on fitness distributions of different features of population dynamics. To test the proposed measures, evolutionary algorithms with different crossover operators, selection pressure levels and population handling techniques have been examined, which lead populations to exhibit a wide range of exploitation-exploration behaviours.

Integrin Structure

2000 ◽  
Vol 28 (4) ◽  
pp. 311-340 ◽  
Author(s):  
M.J. Humphries
Keyword(s):  
Cell Fate ◽  
Molecular Basis ◽  
Tertiary Structure ◽  
Cellular Migration ◽  
Model Studies ◽  
Physical Support ◽  
Tissue Organization ◽  
Wide Range ◽  
Ligand Interactions ◽  
Almost All

The integrins are a family of α,β heterodimeric receptors that mediate dynamic linkages between extracellular adhesion molecules and the intracellular actin cytoskeleton. Integrins are expressed by all multicellular animals, but their diversity varies widely among species; for example, in mammals, 19 α and 8β subunit genes encode polypeptides that combine to form 25 different receptors, whereas the Drosophila and Caenorhabditis genomes encode only five and two integrin a subunits respectively. Thousands of studies over the last two decades have investigated the molecular, cellular and organismal basis of integrin function. Gene deletion has demonstrated essential roles for almost all integrins, with the defects suggesting widespread contributions to both the maintenance of tissue integrity and the promotion of cellular migration. Integrin-ligand interactions are now considered to provide physical support for cells in order to maintain cohesion, to permit the generation of traction forces to enable movement, and to organize signalling complexes to modulate differentiation and cell fate. Animal-model studies have also shown that integrins contribute to the progression of many common diseases, and have implicated them as potential therapeutic targets. The use of anti-integrin monoclonal antibodies and ligand-mimetic peptides has validated this suggestion for inflammatory, neoplastic, traumatic and infectious conditions. Thus, to understand more about the mechanisms underlying tissue organization and cellular trafficking, and to identify approaches for regulating these processes in disease, there is intense interest in determining the molecular basis of integrin function. It is important to state at the outset that the tertiary structure of the integrin dimer is unknown. Our current understanding of the molecular basis of integrin function is therefore compiled from the results of a large number of studies that have employed a wide range of complementary technologies.

scholarly journals MOVABLE-BED MODEL STUDIES OF PERCHED BEACH CONCEPT

1972 ◽  
Vol 1 (13) ◽  
pp. 60
Author(s):  
C.B. Chatham
Keyword(s):  
Three Dimensional ◽  
Normal Wave ◽  
Beach Erosion ◽  
Model Studies ◽  
Model Study ◽  
Wide Range ◽  
Final Design ◽  
Storm Wave ◽  
Wave Conditions ◽  
Movable Bed

Hydraulic model studies were conducted to aid in ascertaining the technical feasibility and optimum design factors of the perched beach concept. Among these were two-dimensional, movable-bed studies to determine an estimate of the amount of sand which would be lost seaward over the submerged toe structure by normal and storm wave action, the optimum elevation of the submerged toe structure, and the length of a stone blanket required to reduce seaward migration of sand to a minimum. The model beach was subjected to test waves until equilibrium was reached for a wide range of wave conditions for both the existing beach and the perched beach. Test results indicate that (a) little or no beachfill material will be lost seaward of the toe structure for normal wave conditions but the larger storm waves may cause erosion of the perched beach, (b) the installation of a stone blanket shoreward of the toe structure will reduce the amount of beach erosion, (c) if the beach fill is extended a sufficient distance seaward, the toe structure serves no useful purpose, and (d) a three-dimensional movable-bed model study is feasible and is necessary to determine the final design features of a perched beach.

scholarly journals No robust evidence of future changes in major stratospheric sudden warmings: a multi-model assessment from CCMI

2018 ◽  
Vol 18 (15) ◽  
pp. 11277-11287 ◽  
Author(s):  
Blanca Ayarzagüena ◽  
Lorenzo M. Polvani ◽  
Ulrike Langematz ◽  
Hideharu Akiyoshi ◽  
Slimane Bekki ◽  
...  
Keyword(s):  
21St Century ◽  
Climate Model ◽  
The Arctic ◽  
Model Assessment ◽  
Polar Night ◽  
Model Studies ◽  
Wide Range ◽  
Stratospheric Sudden Warmings ◽  
The Impact ◽  
Robust Evidence

Abstract. Major mid-winter stratospheric sudden warmings (SSWs) are the largest instance of wintertime variability in the Arctic stratosphere. Because SSWs are able to cause significant surface weather anomalies on intra-seasonal timescales, several previous studies have focused on their potential future change, as might be induced by anthropogenic forcings. However, a wide range of results have been reported, from a future increase in the frequency of SSWs to an actual decrease. Several factors might explain these contradictory results, notably the use of different metrics for the identification of SSWs and the impact of large climatological biases in single-model studies. To bring some clarity, we here revisit the question of future SSW changes, using an identical set of metrics applied consistently across 12 different models participating in the Chemistry–Climate Model Initiative. Our analysis reveals that no statistically significant change in the frequency of SSWs will occur over the 21st century, irrespective of the metric used for the identification of the event. Changes in other SSW characteristics – such as their duration, deceleration of the polar night jet, and the tropospheric forcing – are also assessed: again, we find no evidence of future changes over the 21st century.

scholarly journals The electroweak phase transition: a collider target

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Michael J. Ramsey-Musolf
Keyword(s):  
Thermal History ◽  
Particle Physics ◽  
High Energy ◽  
New Physics ◽  
Electroweak Phase Transition ◽  
Collider Phenomenology ◽  
Model Studies ◽  
Wide Range ◽  
Important Challenge ◽  
History Of

Abstract Determining the thermal history of electroweak symmetry breaking (EWSB) is an important challenge for particle physics and cosmology. Lattice simulations indicate that EWSB in the Standard Model (SM) occurs through a crossover transition, while the presence of new physics beyond the SM could alter this thermal history. The occurrence of a first order EWSB transition would be particularly interesting, providing the needed pre-conditions for generation of the cosmic matter-antimatter asymmetry and sources for potentially observable gravitational radiation. I provide simple, generic arguments that if such an alternate thermal history exists, the new particles involved cannot be too heavy with respect to the SM electroweak temperature, nor can they interact too feebly with the SM Higgs boson. These arguments do not rely on the decoupling limit. I derive corresponding quantitative expectations for masses and interaction strengths which imply that their effects could in principle be observed (or ruled out) by prospective next generation high energy colliders. The simple, generic arguments provide a quantitative, parametric understanding of results obtained in a wide range of explicit model studies; relate them explicitly to the electroweak temperature; and delineate broad contours of collider phenomenology pertaining to a non-standard history of EWSB.

scholarly journals No Robust Evidence of Future Changes in Major Stratospheric Sudden Warmings: A Multi-model Assessment from CCMI

2018 ◽  
Author(s):  
Blanca Ayarzagüena ◽  
Lorenzo M. Polvani ◽  
Ulrike Langematz ◽  
Hideharu Akiyoshi ◽  
Slimane Bekki ◽  
...  
Keyword(s):  
21St Century ◽  
Climate Model ◽  
The Arctic ◽  
Model Assessment ◽  
Single Model ◽  
Model Studies ◽  
Wide Range ◽  
Stratospheric Sudden Warmings ◽  
The Impact ◽  
Robust Evidence

Abstract. Major mid-winter stratospheric sudden warmings (SSWs) are the largest instance of wintertime variability in the Arctic stratosphere. Because SSWs are able to cause significant surface weather anomalies on intra-seasonal time scales, several previous studies have focused on their potential future change, as might be induced by anthropogenic forcings. However, a wide range of results have been reported, from a future increase in the frequency of SSWs to an actual decrease. Several factors might explain these contradictory results, notably the use of different metrics for the identification of SSWs, and the impact of large climatological biases in single-model studies. To bring some clarity, we here revisit the question of future SSWs changes, using an identical set of metrics applied consistently across 12 different models participating in the Chemistry Climate Model Initiative. Our analysis reveals that no statistically significant change in the frequency of SSWs will occur over the 21st century, irrespective of the metric used for the identification of the event. Changes in other SSWs characteristics, such as their duration and the tropospheric forcing, are also assessed: again, we find no evidence of future changes over the 21st century.

The assessment of usefulness of innovative instrumental treatments for non‑invasive reduction of a double chin

2020 ◽  
Vol 3 (1) ◽  
pp. 34-43
Author(s):  
Anna Kroma ◽  
Daria Sobkowska ◽  
Ewa Pelant ◽  
Iwona Micek ◽  
Maria Urbańska ◽  
...  
Keyword(s):  
Aesthetic Surgery ◽  
Lower Face ◽  
Non Invasive ◽  
Wide Range ◽  
The Face ◽  
Face Contour ◽  
Facial Area ◽  
Ageing Skin ◽  
Double Chin ◽  
Instrumental Methods

One of the most common defects in the facial area is the so‑called “double chin”. The problem affects both males and females, and its occurrence is associated with several different factors. It is commonly believed that this defect is a result of excessive adipose tissue location in the lower face. However, the problem seems to be more complex. It is also facilitated by the loss of firmness and elasticity of ageing skin, and in many persons the existence of a double chin results from their anatomical structure, and therefore is determined by genes. Besides, incorrect posture accentuates the defect. It may seem that such minor change does not affect the appearance to a large extent. Whereas, in most cases it causes that the border between the jaw line and the neck disappears what, in turn, distorts the face contour. All this makes a person with a double chin look much older than he or she in fact is. This leads to negative self‑esteem, makes people feel ashamed, and quite often is the main reason for avoiding interaction with other people. So, it is no wonder that persons with such defect seek methods offering its mitigation.Surgical methods give quick and satisfactory effects. However, they are fraught with high risk of complications, and as such they cause anxiety and ultimately discourage patients from making the decision. Luckily, significant improvements in the field of cosmetology and aesthetic surgery offer a wide range of possibilities to reduce a double chin in a manner which is completely non‑invasive, pain free, and does not require long lasting convalescence. In this case, very good results are achieved with the use of innovative technological solutions, such as HIFU and cryolipolysis. Aim. The main aim of this paper is to assess the efficiacy of cryolipolysis in the double chin reduction and the description of innovative instrumental methods allowing for a non‑invasive reduction of this defect.

Exerting control: the grammatical meaning of facial displays in signed languages

2021 ◽  
Vol 32 (4) ◽  
pp. 609-639
Author(s):  
Sara Siyavoshi ◽  
Sherman Wilcox
Keyword(s):  
Information Structure ◽  
Effective Control ◽  
Cognitive Grammar ◽  
Lower Face ◽  
Signed Languages ◽  
Wide Range ◽  
Facial Displays ◽  
The Face ◽  
Upper Face ◽  
Forceful Exertion

Abstract Signed languages employ finely articulated facial and head displays to express grammatical meanings such as mood and modality, complex propositions (conditionals, causal relations, complementation), information structure (topic, focus), assertions, content and yes/no questions, imperatives, and miratives. In this paper we examine two facial displays: an upper face display in which the eyebrows are pulled together called brow furrow, and a lower face display in which the corners of the mouth are turned down into a distinctive configuration that resembles a frown or upside-down U-shape. Our analysis employs Cognitive Grammar, specifically the control cycle and its manifestation in effective control and epistemic control. Our claim is that effective and epistemic control are associated with embodied actions. Prototypical physical effective control requires effortful activity and the forceful exertion of energy and is commonly correlated with upper face activity, often called the “face of effort.” The lower face display has been shown to be associated with epistemic indetermination, uncertainty, doubt, obviousness, and skepticism. We demonstrate that the control cycle unifies the diverse grammatical functions expressed by each facial display within a language, and that they express similar functions across a wide range of signed languages.

Assessment of spillway modeling using computational fluid dynamics

2008 ◽  
Vol 35 (12) ◽  
pp. 1481-1485 ◽  
Author(s):  
Paul G. Chanel ◽  
John C. Doering
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Physical Model ◽  
Flow Data ◽  
Planning Period ◽  
Model Studies ◽  
Wide Range ◽  
Computational Fluid Dynamics Cfd

Throughout the design and planning period for future hydroelectric generating stations, hydraulic engineers are increasingly integrating computational fluid dynamics (CFD) into the process. As a result, hydraulic engineers are interested in the reliability of CFD software to provide accurate flow data for a wide range of structures, including a variety of different spillways. In the literature, CFD results have generally been in agreement with physical model experimental data. Despite past success, there has not been a comprehensive assessment that looks at the ability of CFD to model a range of different spillway configurations, including flows with various gate openings. In this article, Flow-3D is used to model the discharge over ogee-crested spillways. The numerical model results are compared with physical model studies for three case study evaluations. The comparison indicates that the accuracy of Flow-3D is related to the parameter P/Hd.

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