SOBRE POMBOS E GENTE: ALGUMAS OBSERVAÇÕES SOBRE DIFERENÇAS ENTRE ESPÉCIES EM ESCOLHA E AUTOCONTROLE

Cross-species continuity in behavior is widely assumed in behavior analysis, and yet some recent research appears to challenge a strong version of the continuity assumption. This paper reviews potential sources of human-nonhuman discontinuity in the area of choice and self-control. Special emphasis is given to differences in the procedures used to study humans and other animals, which hinder cross-species comparisons. Modifying the procedures used with nonhumans (through the use of token-type reinforcement systems) and with humans (through the use of consumable-type reinforcement systems) brings the choice patterns of humans and other animals into better accord. This suggests that at least some of the reported differences in self-control choices in humans and other animals reflect procedural differences rather than more fundamental differences in behavioral process. By narrowing the methodological chasm separating human and nonhuman procedures, this research points to more effective strategies for assessing cross-species continuity in behavior. Key words: choice, self-control, token reinforcement, consumable reinforcement, species continuity.A continuidade no comportamento entre espécies tem sido amplamente assumida na análise do comportamento, embora pesquisas recentes pareçam desafiar uma versão forte do pressuposto da continuidade. Este artigo apresenta uma revisão de fontes potenciais para a descontinuidade humano-não humano em escolha e auto-controle. Ênfase especial é colocada nas diferenças nos procedimentos empregados para estudar humanos e outros animais, que dificultam comparações entre espécies. Modificações nos procedimentos empregados com não-humanos (por meio do uso de sistemas de reforço do tipo fichas) e com humanos (por meio do emprego de sistemas de reforço do tipo consumatório) mostram maior acordo nos padrões de escolha de humanos e outros animais. Isto sugere que pelo menos algumas das diferenças relatadas sobre escolhas em procedimentos de autocontrole em humanos e outros animais refletem diferenças de procedimento, mais do que diferenças mais fundamentais em processos comportamentais. Ao estreitar as lacunas metodológicas que separam procedimentos empregados com humanos e não humanos, esta pesquisa aponta estratégias mais efetivas para avaliar a continuidade no comportamento entre espécies.Palavras-chave: escolha, autocontrole, reforçamento por fichas, reforço consumatório, continuidade entre espécies

WordCluster: detecting clusters of DNA words and genomic elements

<p>Abstract</p> <p>Background</p> <p>Many <it>k-</it>mers (or DNA words) and genomic elements are known to be spatially clustered in the genome. Well established examples are the genes, TFBSs, CpG dinucleotides, microRNA genes and ultra-conserved non-coding regions. Currently, no algorithm exists to find these clusters in a statistically comprehensible way. The detection of clustering often relies on densities and sliding-window approaches or arbitrarily chosen distance thresholds.</p> <p>Results</p> <p>We introduce here an algorithm to detect clusters of DNA words (<it>k-</it>mers), or any other genomic element, based on the distance between consecutive copies and an assigned statistical significance. We implemented the method into a web server connected to a MySQL backend, which also determines the co-localization with gene annotations. We demonstrate the usefulness of this approach by detecting the clusters of CAG/CTG (cytosine contexts that can be methylated in undifferentiated cells), showing that the degree of methylation vary drastically between inside and outside of the clusters. As another example, we used <it>WordCluster </it>to search for statistically significant clusters of olfactory receptor (OR) genes in the human genome.</p> <p>Conclusions</p> <p><it>WordCluster </it>seems to predict biological meaningful clusters of DNA words (<it>k-</it>mers) and genomic entities. The implementation of the method into a web server is available at <url>http://bioinfo2.ugr.es/wordCluster/wordCluster.php</url> including additional features like the detection of co-localization with gene regions or the annotation enrichment tool for functional analysis of overlapped genes.</p

Opioidergic and dopaminergic modulation of cost/benefit decision-making in Long Evans Rats

Eating disorders are associated with impaired decision-making and dysfunctional reward-related neurochemistry. The present study examined the potential contributions of dopamine and opioid signaling to these processes using two different decision-making tasks. In one task, Long Evans Rats chose between working for a preferred food (high-carbohydrate banana-flavored sucrose pellets) by lever pressing on a progressive-ratio schedule of reinforcement vs. obtaining less preferred laboratory chow that was concurrently available. In a second (effort-free) task, rats chose between the same two reinforcers when they were both available freely. Rats were trained in these tasks before receiving haloperidol (0.00, 0.05, 0.10 mg/kg, intraperitoneally (i.p.)) or naloxone (0.0, 1.5, 3.0 mg/kg, i.p.). In the first task, haloperidol decreased breakpoint, lever presses, number of reinforcers earned, and increased chow intake, whereas naloxone decreased breakpoint and number of reinforcers earned but had no effect on chow consumption. In the effort-free task, haloperidol reduced intakes of both foods without affecting preference, whereas naloxone selectively reduced the consumption of banana-pellets. The present findings support converging evidence suggesting that DA signaling affects processes more closely related to appetitive motivation, leaving other components of motivation unchanged. By contrast, opioid signaling appears to mediate aspects of hedonic feeding by selectively altering intakes of highly palatable foods. For preferred foods, both appetitive and consummatory aspects of food intake were altered by opioid receptor antagonism. Our findings argue against a general suppression of appetite by either compound, as appetite manipulations have been shown to unselectively alter intakes of both types of food regardless of the task employed

Tiempo-fuera del reforzamiento: Restaurando un balance entre análisis y aplicación

El tiempo-fuera del reforzamiento es una de las tecnologías mas exitosas quehan emergido de la investigación conductual básica, pero sorpresivamentese sabe poco sobre sus principios de operación. La mayoría de la investigaciónsobre el tópico del tiempo-fuera ha sido tecnológico—demostrandoque el tiempo fuera funciona—en vez de analítico—porqué funciona. Esteensayo llama a un mayor énfasis sobre las características funcionales deltiempo-fuera, las condiciones bajo las cuales tiene una función aversiva, y afundamentar el trabajo empírico en un marco teórico. Tal retorno a las raícesfuncionales del tiempo fuera del reforzamiento hará que avance no sólo laciencia del tiempo-fuera, sino también sus aplicaciones exitosas

IsoSeek for unbiased and UMI-informed sequencing of miRNAs from low input samples at single-nucleotide resolution

Besides canonical microRNAs (miRNAs), sequence-based variations called iso-miRs have biological relevance and diagnostic potential; however, accurate calling of these post-transcriptional modifications is challenging, especially for low input samples. Here, we present IsoSeek, a sequencing protocol that reduces ligation and PCR amplification bias and improves the accuracy of miRNA detection in low input samples. We describe steps for using randomized adapters combined with unique molecular identifiers (UMI), library quantification, and sequencing, followed by detailed procedures for data processing and analysis.Multiple grants awarded to D.M.P. including NWO Perspectief Cancer-ID, TKI-Health Holland AQrate, and Cancer Center Amsterdam Foundatio

Phase Changes in Ni-Ti Under Laser Shock Loading

Near-equiatomic Ni-Ti, known for its shape memory behavior, can decompose to martensitic phases and/or second phase compounds. This phase competition is investigated in NixTi100-x (494Ti3 but no martensite in the AQ state, consistent with resistivity and dilatometry results which showed no hysteresis indicative of first order phase changes over 1.9 K4Ti3 amounts (present in the AQ state) did change upon loading, indicating the importance of shock-induced heating. A thermodynamically complete equation of state (EOS) for NiTi in its B2 (CsCl) structure was generated by ab initio quantum mechanical calculations. This was tested by performing laser-launched flyer experiments, which showed consistency with the theoretical EOS, validating its use in the prediction of dynamic loading histories in the samples during direct drive loading