Σ1-compactness in languages stronger than

1978 ◽  
Vol 43 (3) ◽  
pp. 508-520 ◽  
Author(s):  
Nigel Cutland
Keyword(s):  
Reflection Principle ◽  
Necessary Condition ◽  
Closed Set ◽  
Skolem Functions ◽  
And Function

One of the main results of Barwise [2] (see also [7, Chapter VIII]) showed that the s – reflection principle for a set A is equivalent to Σ1-compactness of . Here A is any transitive p.r. closed set, and is the infinitary language on A which allows conjunction and disjunction over arbitrary sets Φ Є A, and finite quantification.In this paper we consider languages , where B is a Δ0 subset of A, which is like but we allow quantifiers ∀x and ∃x where x is any set of variables indexed by an element of B. A treatment similar to that of [2] for establishes a sufficient, and in some cases necessary, condition for to be Σ1-compact. The use of infinitary Skolem functions is intrinsic to the method, so to avoid a separate development of the rudiments of the Skolem language we actually define to have b-ary relation and function symbols for every b Є B.

scholarly journals Hypothetico-deductivism in systematics: fact or fiction?

2008 ◽  
Vol 48 (23) ◽  
pp. 263-273 ◽  
Author(s):  
Olivier Rieppel
Keyword(s):  
Scientific Explanation ◽  
Inductive Inference ◽  
Cladistic Analysis ◽  
Phylogenetic Inference ◽  
Total Evidence ◽  
Necessary Condition ◽  
Phylogenetic Systematics ◽  
Relevant Evidence ◽  
The Right ◽  
And Function

Phylogenetic systematics (the cladistic analysis of phylogenetic relationships) is not hypotheticodeductively structured (in the sense of a covering law model of scientific explanation). If it were, there would be no reason to call for total evidence, since that requirement is automatically satisfied in a deductively structured explanation. Instead, the appeal to the requirement of total evidence in phylogenetic systematics indicates that phylogenetic inference is inductively, or abductively, structured. The principle of total evidence has been invoked to render inductive inference an argument as strong as it can be, but for this to be the case the total evidence must also be relevant evidence, i.e., evidence 'of the right sort' relative to the state of affairs to be explained. Character congruence is a necessary condition for phylogenetic inference, but not also a sufficient condition. What is required in addition is the causal grounding of character statements in theories of inheritance, development and function.

scholarly journals Play with Words——Palindrome: a Method to Make English Vocabulary-learning Interesting

2018 ◽  
Vol 8 (2) ◽  
pp. 31
Author(s):  
Peng Yu
Keyword(s):  
Reading Ability ◽  
Vocabulary Learning ◽  
Basic Knowledge ◽  
Necessary Condition ◽  
The Internet ◽  
Language Competence ◽  
English Writing ◽  
English Competence ◽  
Tongue Twister ◽  
And Function

It is commonly believed that one of the unpopular English courses is vocabulary course, because the content is boring, the classroom atmosphere is dull and the students’ enthusiasm is low. Moreover some people think that English vocabulary course is unnecessary and it should only be learned by students themselves. Worse still, some teachers just give up the teaching of vocabulary for they think vocabulary lesson is to recite words and that is the students’ business. But in fact, it is not right, for teacher’s guidance in students’ learning is crucial, and the teaching of vocabulary is important for students’ language competence. English vocabulary learning belongs to the category of basic knowledge, and the basic knowledge of students is a necessary condition and foundation for practical use of English, no matter for oral English competence or English writing and reading ability. It is the responsibility of teachers to think such a question why students have little enthusiasm and weak interest in vocabulary course, and why the classroom atmosphere is dull instead of active and interactive. It is the task of teachers to design a vocabulary course with interesting content and interactive parts to make the lesson vivid and to improve the students’ enthusiasm and interest. Actually, in English vocabulary there are many interesting and meaningful phenomena, such as Spoonerisms, Tongue Twister Fun, oxymoron, Malapropisms, Palindrome, Redundancies, Ambiguities, "Net Lingua" – The Language of the Internet, Etymology: Word Origins, and Pangrams Section, etc., which leave a “space” for language-leaners to find out secret and surprise, and to actively explore and discover something different instead of negatively reciting words. They make the boring vocabulary lesson changed into the interesting and interactive practical course, which is one of the sources of interest for students.The author in this paper intends to give a brief introduction to one of these interesting linguistic phenomena, Palindrome, including definition, origin and function etc., for teachers to use for reference to make their course more vivid and effective.

scholarly journals INTEGRATION AND CELL DECOMPOSITION IN P-MINIMAL STRUCTURES

2016 ◽  
Vol 81 (3) ◽  
pp. 1124-1141 ◽  
Author(s):  
PABLO CUBIDES KOVACSICS ◽  
EVA LEENKNEGT
Keyword(s):  
Cell Decomposition ◽  
Poincaré Series ◽  
Weak Version ◽  
Poincare Series ◽  
Skolem Functions ◽  
Direct Corollary ◽  
Image Position ◽  
And Function ◽  
Constructible Functions

AbstractWe show that the class of ${\cal L}$-constructible functions is closed under integration for any P-minimal expansion of a p-adic field $\left( {K,{\cal L}} \right)$. This generalizes results previously known for semi-algebraic and subanalytic structures. As part of the proof, we obtain a weak version of cell decomposition and function preparation for P-minimal structures, a result which is independent of the existence of Skolem functions. A direct corollary is that Denef’s results on the rationality of Poincaré series hold in any P-minimal expansion of a p-adic field $\left( {K,{\cal L}} \right)$.

scholarly journals Unimodal effects of pigment richness on niche and fitness differences explain species richness and ecosystem function in light-limited phytoplankton communities

2020 ◽  
Author(s):  
Jurg Werner Spaak ◽  
Frederik De Laender
Keyword(s):  
Species Richness ◽  
Ecosystem Function ◽  
Necessary Condition ◽  
Limiting Similarity ◽  
Long Term Effects ◽  
Coexistence Theory ◽  
Trait Diversity ◽  
Niche Differences ◽  
Phytoplankton Communities ◽  
And Function

AbstractTrait diversity is traditionally seen as promoting species richness and ecosystem function. Species with dissimilar traits would partition available resources, increasing niche differences, facilitating coexistence and increasing ecosystem function. Here we first show, using theory and simulations for light-limited phytoplankton, that combing photosynthetic pigments is indeed a necessary condition for coexistence and stimulates ecosystem function. However, pigment richness does mostly not permit the coexistence of more than two species, and increases productivity at most 60% compared to single-pigment communities. Surprisingly, combining all nine pigments known to date leads to a 2.5% probability that four species would coexist, illustrating that the coexistence of a high number of species along a continuous niche axis is constrained by limiting similarity. We explain these constraints by unimodal effects of pigment richness on niche and fitness differences, which jointly limit the positive effect of pigment on species richness. Empirical data and additional simulations suggest that pigment richness effects can be stronger during transient dynamics but inevitably weaken with time, i.e. pigment richness effects on species richness and function are likely short-lived. Our results highlight the need to apply coexistence theory to understand the long-term effects of trait diversity on biodiversity and ecosystem function.Statement of authorshipJ.W.S. and F.dL. developed the ideas and wrote the manuscript. J.W.S developed the mathematics and the python code to conduct the study. J.W.S conducted the literature review.

scholarly journals Play with Words-Palindrome: A Method to Make English Vocabulary-Learning Interesting

2018 ◽  
Vol 2 (1) ◽  
pp. 1
Author(s):  
Peng Yu
Keyword(s):  
Reading Ability ◽  
Vocabulary Learning ◽  
Basic Knowledge ◽  
Necessary Condition ◽  
The Internet ◽  
Language Competence ◽  
English Writing ◽  
English Competence ◽  
Tongue Twister ◽  
And Function

It is commonly believed that one of the unpopular English courses is vocabulary course, because the content is boring, the classroom atmosphere is dull and the students’ enthusiasm is low. Moreover some people think that English vocabulary course is unnecessary and it should only be learned by students themselves. Worse still, some teachers just give up the teaching of vocabulary for they think vocabulary lesson is to recite words and that is the students’ business.But in fact, it is not right, for teacher’s guidance in students’ learning is crucial, and the teaching of vocabulary is important for students’ language competence. English vocabulary learning belongs to the category of basic knowledge, and the basic knowledge of students is a necessary condition and foundation for practical use of English, no matter for oral English competence or English writing and reading ability. It is the responsibility of teachers to think such a question why students have little enthusiasm and weak interest in vocabulary course, and why the classroom atmosphere is dull instead of active and interactive. It is the task of teachers to design a vocabulary course with interesting content and interactive parts to make the lesson vivid and to improve the students’ enthusiasm and interest.Actually, in English vocabulary there are many interesting and meaningful phenomena, such as Spoonerisms, Tongue Twister Fun, oxymoron, Malapropisms, Palindrome, Redundancies, Ambiguities, "Net Lingua" – The Language of the Internet, Etymology: Word Origins, and Pangrams Section, etc., which leave a “space” for language-leaners to find out secret and surprise, and to actively explore and discover something different instead of negatively reciting words. They make the boring vocabulary lesson changed into the interesting and interactive practical course, which is one of the sources of interest for students.The author in this paper intends to give a brief introduction to one of these interesting linguistic phenomena, Palindrome, including definition, origin and function etc., for teachers to use for reference to make their course more vivid and effective.

On the subadditivity of the transfinite diameter

1941 ◽  
Vol 37 (4) ◽  
pp. 373-383 ◽  
Author(s):  
Menahem Schiffer
Keyword(s):  
Function Theory ◽  
Transfinite Diameter ◽  
Closed Set ◽  
Image Position ◽  
And Function ◽  
Set Function ◽  
Set Of Points

Let M be a bounded and closed set of points in the complex z plane; d(M), a set-function which is of great importance in potential and function theory, may then be defined as follows. n points z1, z2, …, zn in M are so chosen that the product of the mutual distanceshas the greatest possible value Then it can be proved thatexists. Thus the set-function d(M), named by Fekete the transfinite diameter of M, is defined.

The Infancy of Solar-Type Stars and its Relevance for the Origin of Life

1997 ◽  
Vol 161 ◽  
pp. 267-282 ◽  
Author(s):  
Thierry Montmerle
Keyword(s):  
Main Sequence ◽  
Solar Nebula ◽  
Circumstellar Disks ◽  
T Tauri Stars ◽  
Necessary Condition ◽  
Sequence Evolution ◽  
T Tauri ◽  
Solar Type ◽  
Optical Domain ◽  
The Origin Of Life

AbstractFor life to develop, planets are a necessary condition. Likewise, for planets to form, stars must be surrounded by circumstellar disks, at least some time during their pre-main sequence evolution. Much progress has been made recently in the study of young solar-like stars. In the optical domain, these stars are known as «T Tauri stars». A significant number show IR excess, and other phenomena indirectly suggesting the presence of circumstellar disks. The current wisdom is that there is an evolutionary sequence from protostars to T Tauri stars. This sequence is characterized by the initial presence of disks, with lifetimes ~ 1-10 Myr after the intial collapse of a dense envelope having given birth to a star. While they are present, about 30% of the disks have masses larger than the minimum solar nebula. Their disappearance may correspond to the growth of dust grains, followed by planetesimal and planet formation, but this is not yet demonstrated.

Conformation of Ribosomes from Escherichia Coli

1974 ◽  
Vol 32 ◽  
pp. 210-211
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Binding Sites ◽  
Ribosomal Proteins ◽  
Fluorescent Dyes ◽  
Protein Biosynthesis ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Dimensional Structure ◽  
Complete Understanding ◽  
And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

The Effect of Oxidized Cholesterol on the Aorta of Rabbits- Scanning Electron Microscopic Observations

1982 ◽  
Vol 40 ◽  
pp. 340-341
Author(s):  
S. K. Pena ◽  
C. B. Taylor ◽  
J. Hill ◽  
J. Safarik
Keyword(s):  
Cholesterol Biosynthesis ◽  
Cholesterol Content ◽  
Arterial Injury ◽  
Electron Microscopic ◽  
Aortic Smooth Muscle ◽  
Oxidized Cholesterol ◽  
Initial Event ◽  
Membrane Structure And Function ◽  
Scanning Electron Microscopic ◽  
And Function

Introduction: Oxidized cholesterol derivatives have been demonstrated in various cell cultures to be very potent inhibitors of 3-hvdroxy-3- methylglutaryl Coenzyme A reductase which is a principle regulator of cholesterol biosynthesis in the cell. The cholesterol content in the cells exposed to oxidized cholesterol was found to be markedly decreased. In aortic smooth muscle cells, the potency of this effect was closely related to the cytotoxicity of each derivative. Furthermore, due to the similarity of their molecular structure to that of cholesterol, these oxidized cholesterol derivatives might insert themselves into the cell membrane, alter membrane structure and function and eventually cause cell death. Arterial injury has been shown to be the initial event of atherosclerosis.

Ultrastructure of developing visual cortical synapses in the cat superior colliculus

1991 ◽  
Vol 49 ◽  
pp. 156-157
Author(s):  
Caroline A. Miller ◽  
Laura L. Bruce
Keyword(s):  
Superior Colliculus ◽  
Phosphate Buffer ◽  
Receptive Fields ◽  
Visual Cortical Area ◽  
Cortical Synapses ◽  
Visual Cortical ◽  
And Function ◽  
Phosphate Buffered Saline ◽  
The Brain ◽  
Cat Superior Colliculus

The first visual cortical axons arrive in the cat superior colliculus by the time of birth. Adultlike receptive fields develop slowly over several weeks following birth. The developing cortical axons go through a sequence of changes before acquiring their adultlike morphology and function. To determine how these axons interact with neurons in the colliculus, cortico-collicular axons were labeled with biocytin (an anterograde neuronal tracer) and studied with electron microscopy.Deeply anesthetized animals received 200-500 nl injections of biocytin (Sigma; 5% in phosphate buffer) in the lateral suprasylvian visual cortical area. After a 24 hr survival time, the animals were deeply anesthetized and perfused with 0.9% phosphate buffered saline followed by fixation with a solution of 1.25% glutaraldehyde and 1.0% paraformaldehyde in 0.1M phosphate buffer. The brain was sectioned transversely on a vibratome at 50 μm. The tissue was processed immediately to visualize the biocytin.

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