bluuebunny/crossref_metadata_2025_split huggingface dataset:
Backcross versus Forward Breeding in the Development of Transgenic Maize Hybrids: Theory and Practice
Authors: Mumm Rita H. 
Published: December 2007

ABSTRACTKey factors affecting the choice of breeding methods employed in the development of transgenic maize (Zea mays L.) hybrids are identified and evaluated, particularly as these pertain to the use and balance of backcross and forward breeding in the overall design of a breeding program. These factors are type of trait, population(s) under selection, the predicted response to selection, stewardship of transgenic events, costs, and risks. Analysis suggested that simultaneous hybrid improvement and event integration via a forward breeding approach is not practical, given that some level of backcrossing is basic to event integration and the need to contain events not fully authorized by the local government for cultivation, food, and feed. Considering event integration conducted in a stream separate from hybrid improvement, a forward breeding component to event integration may be warranted, particularly if a threshold level of expression of the transgenic trait of interest is dependent on endogenous alleles that interact with the event, some of which may be influenced by the environment. For this situation, directives are given for determining the number of generations of backcrossing to be conducted to create partial conversions from which to select for favorable endogenous alleles via forward breeding. In addition, ways to maximize the advantages of a backcross‐only approach to event integration are discussed.
Education and Preparation of Plant Breeders for Careers in Global Crop Improvement
Authors: Bliss Fredrick A. 
Published: December 2007

ABSTRACTPlant breeding is essential to global food security and to a viable strategy for developing efficient plant sources for biofuels. Despite expanding demand for professionals educated in breeding fundamentals and able to integrate evolving new technology for crop improvement, public‐supported programs are diminishing. To meet future needs for breeders engaged in cultivar development, prebreeding and population improvement, biotechnology and applied genomics, and education and training, greater support must be forthcoming from public funding and businesses that are future employers. Colleges and universities with supporting curricula should work together to develop collaborative programs and courses of study that prepare new graduates for future employment, which will be largely in the private sector in developed countries and the public sector in developing countries. Broad‐based efforts to increase public awareness about the impact of plant breeding and inform students about career opportunities are needed to assure that highly qualified, dedicated new professionals replace the large numbers of current breeders nearing retirement.
The Use of Doubled Haploids in Recurrent Selection and Hybrid Development in Maize
Authors: Gallais A. , Bordes J. 
Published: December 2007

ABSTRACTProgress made around the in situ gynogenesis technique allows production in a great number of maize (Zea mays L.) doubled‐haploid (DH) lines. Doubled haploids are now largely used in maize breeding. To optimize their use in breeding schemes, it is first required to know whether genetic variation expressed at the level of DH lines is the same as at the level of lines from self‐fertilization. In several experiments, with evaluation for testcross performance, good agreement appears between variance expressed in selfed progenies and DH variance for grain yield. Recurrent selection (RS) for testcross performance using doubled haploids (DH‐RS) can then be compared to the use of Sn (SnT) plants (S0, S1, S2, …). From a theoretical approach by numerical application, it was shown that, with the same selection intensity and without off‐season nurseries, DH‐RS in four years gives the highest genetic advance per year. With the use of off‐season nurseries, the same investment in trials and the same rate of reduction of effective population size, to have the advantage of DH‐RS the cycle length must be reduced to three years and for traits of low heritability. In an experiment comparing two cycles of RS‐S0T selection in four years to one cycle of DH‐RS (in three or four years), considering the expected gain per year with a DH‐RS cycle in four years, there was an advantage to RS‐S0T, whereas with a three‐year cycle for the DH method both methods were expected to be equivalent. The observed genetic gains were similar for one DH‐RS cycle and the two RS‐S0T cycles in four years. In conclusion, there is not a greater advantage from using doubled haploids in RS. However, DH‐RS has the advantage of simultaneously producing lines that are directly usable as parents of a hybrid. From a theoretical approach, it is shown that DH‐RS is expected to be the best method at the level of genetic advance in variety development, even for medium heritabilities. Furthermore, the whole process appears to be less costly than conventional methods. Use of doubled haploids can thus be very efficient in maize breeding.
Evaluating Potential Genetic Gains in Wheat Associated with Stress‐Adaptive Trait Expression in Elite Genetic Resources under Drought and Heat Stress
Authors: Reynolds Matthew P. , Pierre Carolina Saint , Saad Abu S.I. , Vargas Mateo , Condon Anthony G. 
Published: December 2007

ABSTRACTWhile genetic resources provide an invaluable gene pool for crop breeding, the majority of accessions in germplasm collections remain uncharacterized and their potential to improve stress adaptation is not quantified. A selection of 25 elite genetic resources for wheat (Triticum aestivum L.) were characterized for agronomic and physiological trait expression in drought‐ and heat‐stressed environments. Under drought, the physiological traits best associated with yield were canopy temperature, associated with water uptake, and carbon isotope discrimination, associated with transpiration efficiency. Under heat stress stomatal conductance, leaf chlorophyll content, and canopy temperature (associated with radiation use efficiency in this environment) were well correlated with yield. Theoretical yield gains based on extrapolating the best trait expression to the highest yielding backgrounds were also estimated. Under drought, the best expression of canopy temperature and carbon isotope discrimination suggested potential yield gains of approximately 10 and 9% above the best yielding cultivars, respectively; under heat stress, canopy temperature and remobilization of stem carbohydrates suggested potential yield gains of approximately 7 and 9%, respectively. Other physiological trait expression was associated with potential yield gains to varying degrees. When considering agronomic traits, the best expression of harvest index suggested yield gains of approximately 14 and 24% in drought and hot environments, respectively, while the combined best expression of both harvest index and final aboveground biomass suggested yield gains of 30 and 34%, respectively. Principal component analysis indicated that many of the physiological traits that were associated with yield and biomass were not strongly associated with each other, suggesting potential cumulative gene action for yield if traits were combined. When comparing trait expression across drought and hot environments, several physiological traits (e.g., canopy temperature) showed closer association with each other than did performance traits, supporting the idea that such stress‐adaptive traits have generic value across stresses.
The disjunction and related properties for constructive Zermelo-Fraenkel set theory
Authors: Rathjen Michael 
Published: December 2007

AbstractThis paper proves that the disjunction property, the numerical existence property. Church's rule, and several other metamathematical properties hold true for Constructive Zermelo-Fraenkel Set Theory, CZF, and also for the theory CZF augmented by the Regular Extension Axiom.As regards the proof technique, it features a self-validating semantics for CZF that combines realizability for extensional set theory and truth.
Cofinal families of Borel equivalence relations and quasiorders
Authors: Rosendal Christian 
Published: December 2007

AbstractFamilies of Borel equivalence relations and quasiorders that are cofinal with respect to the Borel reducibility ordering. ≤B, are constructed. There is an analytic ideal on ω generating a complete analytic equivalence relation and any Borel equivalence relation reduces to one generated by a Borel ideal. Several Borel equivalence relations, among them Lipschitz isomorphism of compact metric spaces, are shown to beKσcomplete.
Subsimple groups
Authors: Wagner Frank 
Published: December 2007

AbstractWe define a notion of genericity for arbitrary subgroups of groups interpretable in a simple theory, and show that a type generic for such a group is generic for the minimal hyperdefinable supergroup (the definable hull). In particular, at least one generic type of the definable hull is finitely satisfiable in the original subgroup. If the subgroup is a subfield. then the additive and the multiplicative definable hull both have bounded index in the smallest hyperdefinable superfield.
On a conjecture of Dobrinen and Simpson concerning almost everywhere domination
Authors: Binns Stephen , Kjos-Hanssen Bjørn , Lerman Manuel , Solomon Reed 
Published: December 2007

Dobrinen and Simpson [4] introduced the notions of almost everywhere domination and uniform almost everywhere domination to study recursion theoretic analogues of results in set theory concerning domination in generic extensions of transitive models of ZFC and to study regularity properties of the Lebesgue measure on 2ω in reverse mathematics. In this article, we examine one of their conjectures concerning these notions.Throughout this article, ≤T denotes Turing reducibility and μ denotes the Lebesgue (or “fair coin”) probability measure on 2ω given byA property holds almost everywhere or for almost all X ∈ 2ω if it holds on a set of measure 1. For f, g ∈ ωω, f dominatesg if ∃m∀n < m(f(n) > g(n)).(Dobrinen, Simpson). A set A ∈ 2ωis almost everywhere (a.e.) dominating if for almost all X ∈ 2ω and all functions g ≤TX, there is a function f ≤TA such that f dominates g. A is uniformly almost everywhere (u.a.e.) dominating if there is a function f ≤TA such that for almost all X ∈ 2ω and all functions g ≤TX, f dominates g.There are several trivial but useful observations to make about these definitions. First, although these properties are stated for sets, they are also properties of Turing degrees. That is, a set is (u.)a.e. dominating if and only if every other set of the same degree is (u.)a.e. dominating. Second, both properties are closed upwards in the Turing degrees. Third, u.a.e. domination implies a.e. domination. Finally, if A is u.a.e. dominating, then there is a function f ≤TA which dominates every computable function.
Correspondences between gentzen and hilbert systems
Authors: Raftery J.G. 
Published: December 2007

Most Gentzen systems arising in logic contain few axiom schemata and many rule schemata. Hilbert systems, on the other hand, usually contain few proper inference rules and possibly many axioms. Because of this, the two notions tend to serve different purposes. It is common for a logic to be specified in the first instance by means of a Gentzen calculus, whereupon a Hilbert-style presentation ‘for’ the logic may be sought—or vice versa. Where this has occurred, the word ‘for’ has taken on several different meanings, partly because the Gentzen separator ⇒ can be interpreted intuitively in a number of ways. Here ⇒ will be denoted less evocatively by ⊲.In this paper we aim to discuss some of the useful ways in which Gentzen and Hilbert systems may correspond to each other. Actually, we shall be concerned with thededucibility relationsof the formal systems, as it is these that are susceptible to transformation in useful ways. To avoid potential confusion, we shall speak of Hilbert and Gentzenrelations. By aHilbert relationwe mean any substitution-invariant consequence relation onformulas—this comes to the same thing as the deducibility relation of a set of Hilbert-style axioms and rules. By aGentzen relationwe mean the fully fledged generalization of this notion in whichsequentstake the place of single formulas. In the literature, Hilbert relations are often referred to assentential logics. Gentzen relations as defined here are their exactsequentialcounterparts.
Abstract Beth definability in institutions
Authors: Petria Marius , Diaconescu Răzvan 
Published: December 2007

AbstractThis paper studies definability within the theory of institutions, a version of abstract model theory that emerged in computing science studies of software specification and semantics. We generalise the concept of definability to arbitrary logics, formalised as institutions, and we develop three general definability results. One generalises the classical Beth theorem by relying on the interpolation properties of the institution. Another relies on a meta Birkhoff axiomatizability property of the institution and constitutes a source for many new actual definability results, including definability in (fragments of) classical model theory. The third one gives a set of sufficient conditions for ‘borrowing’ definability properties from another institution via an ‘adequate’ encoding between institutions.The power of our general definability results is illustrated with several applications to (many-sorted) classical model theory and partial algebra, leading for example to definability results for (quasi-)varieties of models or partial algebras. Many other applications are expected for the multitude of logical systems formalised as institutions from computing science and logic.
On the available partial respects in which an axiomatization for real valued arithmetic can recognize its consistency
Authors: Willard Dan E. 
Published: December 2007

AbstractGödel's Second Incompleteness Theorem states axiom systems of sufficient strength are unable to verify their own consistency. We will show that axiomatizations for a computer's floating point arithmetic can recognize their cut-free consistency in a stronger respect than is feasible under integer arithmetics. This paper will include both new generalizations of the Second Incompleteness Theorem and techniques for evading it.
Glivenko theorems for substructural logics over FL
Authors: Galatos Nikolaos , Ono Hiroakira 
Published: December 2007

AbstractIt is well known that classical propositional logic can be interpreted in intuitionistic prepositional logic. In particular Glivenko's theorem states that a formula is provable in the former iff its double negation is provable in the latter. We extend Glivenko's theorem and show that for every involutive substructural logic there exists a minimum substructural logic that contains the first via a double negation interpretation. Our presentation is algebraic and is formulated in the context of residuated lattices. In the last part of the paper, we also discuss some extended forms of the Koltnogorov translation and we compare it to the Glivenko translation.
Intensional models for the theory of types
Authors: Muskens Reinhard 
Published: December 2007

AbstractIn this paper we defineintensionalmodels for the classical theory of types, thus arriving at an intensional type logic ITL. Intensional models generalize Henkin's general models and have a natural definition. As a class they do not validate the axiom of Extensionality. We give a cut-free sequent calculus for type theory and show completeness of this calculus with respect to the class of intensional models via a model existence theorem. After this we turn our attention to applications. Firstly, it is argued that, sinceITLis truly intensional, it can be used to model ascriptions of propositional attitude without predictinglogical omniscience. In order to illustrate this a small fragment of English is defined and provided with anITLsemantics. Secondly, it is shown thatITLmodels contain certain objects that can be identified withpossible worlds. Essential elements of modal logic become available within classical type theory once the axiom of Extensionality is given up.
Relation algebra reducts of cylindric algebras and complete representations
Authors: Hirsch Robin 
Published: December 2007

AbstractWe show, for any ordinalγ≥ 3, that the classℜaCAγis pseudo-elementary and has a recursively enumerable elementary theory. ScKdenotes the class of strong subalgebras of members of the classK. We devise games,Fn(3 ≤n≤ω),G, H, and show, for an atomic relation algebrawith countably many atoms, thatfor 3 ≤n<ω. We use these games to show, forγ> 5 and any classKof relation algebras satisfyingthatKis not closed under subalgebras and is not elementary. For infiniteγ, the inclusion ℜaCAγ⊂ScℜaCAγis strict.For infiniteγand for a countable relation algebrawe show thathas a complete representation if and only ifis atomic and ∃ has a winning strategy inF(At()) if and only ifis atomic and∈ScℜaCAγ.
On notions of genericity and mutual genericity
Authors: Truss J. K. 
Published: December 2007

AbstractGeneric automorphisms of certain homogeneous structures are considered, for instance, the rationals as an ordered set, the countable universal homogeneous partial order, and the random graph. Two of these cases were discussed in [7], where it was shown that there is a generic automorphism of the second in the sense introduced in [10], In this paper, I study various possible definitions of ‘generic’ and ‘mutually generic’, and discuss the existence of mutually generic automorphisms in some cases. In addition, generics in the automorphism group of the rational circular order are considered.
Reconstruction of homogeneous relational structures
Authors: Barbina Silvia , Macpherson Dugald 
Published: December 2007

This paper contains a result on the reconstruction of certain homogeneous transitive ω-categorical structures from their automorphism group. The structures treated are relational. In the proof it is shown that their automorphism group contains a generic pair (in a slightly non-standard sense, coming from Baire category).Reconstruction results give conditions under which the abstract group structure of the automorphism group Aut() of an ω-categorical structure determines the topology on Aut(), and hence determines up to bi-interpretability, by [1]; they can also give conditions under which the abstract group Aut() determines the permutation group ⟨Aut (), ⟩. so determines up to bi-definability. One such condition has been identified by M. Rubin in [12], and it is related to the definability, in Aut(), of point stabilisers. If the condition holds, the structure is said to have a weak ∀∃ interpretation, and Aut() determines up to bi-interpretability or, in some cases, up to bi-definability.A better-known approach to reconstruction is via the ‘small index property’: an ω-categorical stucture has the small index property if any subgroup of Aut() of index less than is open. This guarantees that the abstract group structure of Aut() determines the topology, so if is ω-categorical with Aut() ≅ Aut() then and are bi-interpretable.
Turing computable embeddings
Authors: Knight Julia F. , Miller Sara , Boom M. Vanden 
Published: December 2007

AbstractIn [3]. two different effective versions of Borel embedding are defined. The first, called computable embedding, is based on uniform enumeration reducibility. while the second, called Turing computable embedding, is based on uniform Turing reducibility. While [3] focused mainly on computable embeddings, the present paper considers Turing computable embeddings. Although the two notions are not equivalent, we can show that they behave alike on the mathematically interesting classes chosen for investigation in [3]. We give a “Pull-back Theorem”, saying that if Ф is a Turing computable embedding of K into K′, then for any computable infinitary sentence φ in the language of K′, we can find a computable infinitary sentence φ* in the language of K such that for all A ∈ K A ⊨ φ* iff Φ (A) ⊨ φ and φ* has the same “complexity” as φ (i.e., if φ is computable Σα or computable Πα, for α ≥ 1, then so is φ*). The Pull-back Theorem is useful in proving non-embeddability, and it has other applications as well.
Characterizing rosy theories
Authors: Ealy Clifton , Onshuus Alf 
Published: December 2007

AbstractWe examine several conditions, either the existence of a rank or a particular property of þ-forking that suggest the existence of a well-behaved independence relation, and determine the consequences of each of these conditions towards the rosiness of the theory. In particular we show that the existence of an ordinal valued equivalence relation rank is a (necessary and) sufficient condition for rosiness.
Π10 classes and strong degree spectra of relations
Authors: Chisholm John , Chubb Jennifer , Harizanov Valentina S. , Hirschfeldt Denis R. , Jockusch Carl G. , McNicholl Timothy , Pingrey Sarah 
Published: December 2007

AbstractWe study the weak truth-table and truth-table degrees of the images of subsets of computable structures under isomorphisms between computable structures. In particular, we show that there is a low c.e. set that is not weak truth-table reducible to any initial segment of any scattered computable linear ordering. Countable subsets of 2ω and Kolmogorov complexity play a major role in the proof.
The Role of Gateway Drugs and Psychosocial Factors in Substance Dependence in Eastern India
Authors: Saddichha Sahoo , Sinha Baxi Neeraj Prasad , Khess C. R. J. 
Published: December 2007

Objective: Western studies have identified the gateway patterns of substance use which lead the way from the so called “Soft Drugs” (like nicotine, etc.) to the “Hard Drugs” (like Opioids) [the Gateway hypothesis]. Nicotine and alcohol have been implicated as the most common initiating drugs in studies from different places, however, studies are lacking from this region. This study was designed to find the drugs of initiation and to understand the factors for initiation, maintenance, and relapse of these substances in persons dependent on them in Eastern India. Method: Seventy subjects with ICD 10 DCR diagnosis of substance dependence admitted consecutively in Center for Addiction Psychiatry, Central Institute of Psychiatry (CIP), Ranchi, were taken up for the study after taking written informed consent. A semi-structured questionnaire including the substance use part of Mini International Neuropsychiatric Inventory (MINI) was administered. Results: Alcohol and opioids were the most common drugs of dependence but nicotine and alcohol were found to be the most common initiating drugs in both alcohol and opioid groups. Persons dependent on opioids presented earlier for treatment, with earlier development of withdrawal symptoms and having completed lesser years of formal education, and had higher monthly incomes as compared to those dependent on alcohol. The most common psychosocial factors determining initiation and maintenance were peer pressure or curiosity. Conclusions: If adolescents and youth can be motivated to stay away even from the “gateway drugs” by targeting common initiation factors, it may lead to delay in dependence or possibly avoidance of development of dependence.