Proof-Pattern Recognition and Lemma Discovery in ACL2

We present a novel technique for combining statistical machine learning for proof-pattern recognition with symbolic methods for lemma discovery. The resulting tool, ACL2(ml), gathers proof statistics and uses statistical pattern-recognition to pre-processes data from libraries, and then suggests auxiliary lemmas in new proofs by analogy with already seen examples. This paper presents the implementation of ACL2(ml) alongside theoretical descriptions of the proof-pattern recognition and lemma discovery methods involved in it

Band Mapping in One-Step Photoemission Theory: Multi-Bloch-Wave Structure of Final States and Interference Effects

A novel Bloch-waves based one-step theory of photoemission is developed within the augmented plane wave formalism. Implications of multi-Bloch-wave structure of photoelectron final states for band mapping are established. Interference between Bloch components of initial and final states leads to prominent spectral features with characteristic frequency dispersion experimentally observed in VSe_2 and TiTe_2. Interference effects together with a non-free-electron nature of final states strongly limit the applicability of the common direct transitions band mapping approach, making the tool of one-step analysis indispensable.Comment: 4 jpg figure

Understanding Microbial Divisions of Labor

Divisions of labor are ubiquitous in nature and can be found at nearly every level of biological organization, from the individuals of a shared society to the cells of a single multicellular organism. Many different types of microbes have also evolved a division of labor among its colony members. Here we review several examples of microbial divisions of labor, including cases from both multicellular and unicellular microbes. We first discuss evolutionary arguments, derived from kin selection, that allow divisions of labor to be maintained in the face of non-cooperative cheater cells. Next we examine the widespread natural variation within species in their expression of divisions of labor and compare this to the idea of optimal caste ratios in social insects. We highlight gaps in our understanding of microbial caste ratios and argue for a shift in emphasis from understanding the maintenance of divisions of labor, generally, to instead focusing on its specific ecological benefits for microbial genotypes and colonies. Thus, in addition to the canonical divisions of labor between, e.g., reproductive and vegetative tasks, we may also anticipate divisions of labor to evolve to reduce the costly production of secondary metabolites or secreted enzymes, ideas we consider in the context of streptomycetes. The study of microbial divisions of labor offers opportunities for new experimental and molecular insights across both well-studied and novel model systems

Understanding microbial divisions of labor

Divisions of labor are ubiquitous in nature and can be found at nearly every level of biological organization, from the individuals of a shared society to the cells of a single multicellular organism. Many different types of microbes have also evolved a division of labor among its colony members. Here we review several examples of microbial divisions of labor, including cases from both multicellular and unicellular microbes. We first discuss evolutionary arguments, derived from kin selection, that allow divisions of labor to be maintained in the face of non-cooperative cheater cells. Next we examine the widespread natural variation within species in their expression of divisions of labor and compare this to the idea of optimal caste ratios in social insects. We highlight gaps in our understanding of microbial caste ratios and argue for a shift in emphasis from understanding the maintenance of divisions of labor, generally, to instead focusing on its specific ecological benefits for microbial genotypes and colonies. Thus, in addition to the canonical divisions of labor between, e.g., reproductive and vegetative tasks, we may also anticipate divisions of labor to evolve to reduce the costly production of secondary metabolites or secreted enzymes, ideas we consider in the context of streptomycetes. The study of microbial divisions of labor offers opportunities for new experimental and molecular insights across both well-studied and novel model systems

Strictly One-Dimensional Electron System in Au Chains on Ge(001) Revealed By Photoelectron K-Space Mapping

Atomic nanowires formed by Au on Ge(001) are scrutinized for the band topology of the conduction electron system by k-resolved photoemission. Two metallic electron pockets are observed. Their Fermi surface sheets form straight lines without undulations perpendicular to the chains within experimental uncertainty. The electrons hence emerge as strictly confined to one dimension. Moreover, the system is stable against a Peierls distortion down to 10 K, lending itself for studies of the spectral function. Indications for unusually low spectral weight at the chemical potential are discussed.Comment: 4 pages, 4 figures - revised version with added Fig. 2e) and additional reference

Mutational meltdown of putative microbial altruists in Streptomyces coelicolor colonies

In colonies of the filamentous multicellular bacterium Streptomyces coelicolor, a subpopulation of cells arises that hyperproduces metabolically costly antibiotics, resulting in a division of labor that increases colony fitness. Because these cells contain large genomic deletions that cause massive reductions to individual fitness, their behavior is similar to altruistic worker castes in social insects or somatic cells in multicellular organisms. To understand these mutant cells’ reproductive and genomic fate after their emergence, we use experimental evolution by serially transferring populations via spore-to-spore transfer for 25 cycles, reflective of the natural mode of bottlenecked transmission for these spore-forming bacteria. We show that in contrast to wild-type cells, putatively altruistic mutant cells continue to decline in fitness during transfer while they lose more fragments from their chromosome ends. In addition, the base-substitution rate in mutants increases roughly 10-fold, possibly due to mutations in genes for DNA replication and repair. Ecological damage, caused by reduced sporulation, coupled with DNA damage due to point mutations and deletions, leads to an inevitable and irreversible type of mutational meltdown in these cells. Taken together, these results suggest the cells arising in the S. coelicolor division of labor are analogous to altruistic reproductively sterile castes of social insects

Manual de métodos de análise de solo.

Analises fisicas; Preparo da amostra; Terra fina, cascalho e calhaus;Umidade atual; Umidade residual e fator "f"; Umidade obtida no aparelho extrator de Richards; Umidade obtida com a mesa de tensao; Densidade aparente; Porosidade total; Microporosidade (Metodo Mesa de Tensao); Macroporosidade; Analise granulometrica (Dispersao Total); Argila dispersa em agua; Grau de floculacao; Relacao silte/argila; Condutividade hidraulica; Percentagem de saturacao; Percentagem de agregados; Limite de liquidez; Limite e indice de plasticidade; Limite de pegajosidade; Limite de contracao (LC) (Metodo do Mercurio Metalico); Grau de contracao (GC); Superficie especifica (Metodo Simplificado); Separacao de argila e silte para analises de raios X; Coeficiente de extensibilidadelinear (COLE); Expressao dos resultados; Parte II - Analises quimicas; pH (agua, KCl, CaCl2); Carbono organico; Nitrogenio total; Capacidadede troca de cations (CTC) e bases trocaveis; Acidez do solo; Hidrogenio extraivel; Valor T - CTC (Capacidade de Troca de Cations); Valor V (Percentagem de Saturacao de Bases); Percentagem de saturacao com aluminio; Percentagem de saturacao com sodio; Troca compulsiva (CTC e CTA)Ponto de carga zero (PCZ); Ataque sulfurico; Silica; Ferro no extrato sulfurico; Aluminio no extrato sulfurico; Titanio no extrato sulfuricoManganes no extrato sulfurico; Fosforo no extrato sulfurico; Relacoes moleculares Ki e Kr; Relacao molecular Al2O3/ Fe2O3; Ferro, aluminio,manganes e silica extraiveis; Sais soluveis; Equivalente de carbono ...bitstream/item/169149/1/Manual-de-metodos-de-analise-de-solo-2-ed-1997.pdf2. ed. rev. e atual.Autores: Marie Elisabeth Christine Claessen (Organização), Washington de Oliveira Barreto (Coordenação técnica), José Lopes de Paula, Mariza Nascimento Duarte

Інвестиційне кредитування переробних підприємств АПК банківськими установами

Метою статті є аналіз динаміки інвестиційного кредитування банківськими установами переробних підприємств агропромислового комплексу. Під час проведення дослідження були використані аналітичний, статистико – економічний, графічний, порівняльний методи та метод системного аналізу