Elaborate Hypotheses Research Articles

The Effect of Structure on the Memory for Procedural Text.

The present study examined how the structure of procedural texts affected recall of those texts. Past research has found that procedural text is comprehended best when readers expend a moderate amount of effort in processing it; the amount of effort may depend on the structure of the procedural text. Sixty-three participants read six procedural texts describing how to construct simple machines. One group of participants read texts that contained a diagram of the object, whereas the other group read texts with no diagram. Two types of texts were presented: Narrative and list-like procedural texts. Results showed that rereading increased recall of the list-like text, but had little effect for the narrative text. The elaboration hypothesis explains the recall differences after a single reading, but it is still unclear why the list-like texts were recalled better than the narrative texts after a second reading.

Chloroplast history clarified by the criterion of light-harvesting complex

Bacterial essence of mitochondria and chloroplasts was initially proclaimed in general outline. Later, the remarkable insight gave way to an elaborate hypothesis. Finally, it took shape of a theory confirmed by molecular biology data. In particular, the rrn operon, which is the key phylogeny marker, locates chloroplasts on the tree of Cyanobacteria. Chloroplast ancestry and diversity can be also traced with the rpoС and psbA genes, rbc operon, and other molecular criteria of prime importance. Another criterion, also highly reliable, is light-harvesting complex (LHC). LHC pigment and protein moieties specify light acclimation strategies in evolutionary retrospect and modern biosphere. The onset of symbiosis between eukaryotic host and pre-chloroplast, as well as further mutual adjustment of partners depended on physiological competence of LHC. In this review, the criterion of LHC is applied to the origin and diversity of chloroplasts. In particular, ancient cyanobacterium possessing tandem antenna (encoded by the cbp genes and the pbp genes, correspondingly), and defined as a prochlorophyte, is argued to be chloroplast ancestor.

Model systems for regeneration: the spiny mouse, Acomys cahirinus.

The spiny mouse, Acomys spp., is a recently described model organism for regeneration studies. For a mammal, it displays surprising powers of regeneration because it does not fibrose (i.e. scar) in response to tissue injury as most other mammals, including humans, do. In this Primer article, we review these regenerative abilities, highlighting the phylogenetic position of the spiny mouse relative to other rodents. We also briefly describe the Acomys tissues that have been used for regeneration studies and the common features of their regeneration compared with the typical mammalian response. Finally, we discuss the contribution that Acomys has made in understanding the general principles of regeneration and elaborate hypotheses as to why this mammal is successful at regenerating.

Débattre pour apprendre en sciences expérimentales : le cas de la circulation sanguine

The present research questions the cognitive work of French upper secondary school students (14-15 years old) during a debate in science class. The debate is based on experimental manipulations related to bloodstream. The study follows the types of reasoning and the notion of truth brought by students and their cognitive displacement. For that, it uses indicators such as modelling and problematisation based on the study of language interactions used by the students considered. The importance of a debate during an empiric experimental situation in biology in the classroom is highlighted. The introduction of a discursive phase in such an experimental situation promoted the articulation between description, explanation and argumentation, and as a consequence, the construction of more elaborate hypotheses and explanatory models that were subjected to critic and experimentation.

Confabulation or experience? Implications of out-of-body experiences for theories of consciousness

Difficulties in distinguishing veridical reports of experience from confabulations have implications for theories of consciousness. I develop some of these implications through a consideration of out-of-body experiences (OBEs). Do these variations indicate individual variation in experience or are they post-hoc confabulations, stories told by subjects to themselves in an attempt to make sense of the core phenomenology? I argue that no existent or possible evidence would be sufficient to favour one hypothesis over the other. How such evidence is interpreted depends on prior commitments to one or other of these hypotheses or to a theory of consciousness that is not neutral as to these hypotheses. One of these types of theory, namely vehicle theories, has difficulty accommodating the existence of confabulations and so allows for only the elaborate phenomenology hypothesis. Because we cannot know that reports are not confabulations, vehicle theories are insufficient to explain OBEs.

Angiotensin II infusion into ApoE-/- mice: a model for aortic dissection rather than abdominal aortic aneurysm?

Angiotensin II-infused ApoE-/- mice are a popular mouse model for preclinical aneurysm research. Here, we provide insight in the often-reported but seldom-explained variability in shape of dissecting aneurysms in these mice. N = 45 excised aortas were scanned ex vivo with phase-contrast X-ray tomographic microscopy. Micro-ruptures were detected near the ostium of celiac and mesenteric arteries in 8/11 mice that were sacrificed after 3 days of angiotensin II-infusion. At later time points (after 10, 18, and 28 days) the variability in shape of thoraco-abdominal lesions (occurring in 31/34 mice) was classified into 7 different categories based on the presence or absence of a medial tear (31/31), an intramural hematoma (23/31) or a false channel (11/23). Medial tears were detected both in the thoracic and the abdominal aorta and were most prevalent at the left and ventral aspects of celiac and mesenteric arteries. The axial length of the hematoma strongly correlated to the total number of ruptured branch ostia (r2 = 0.78) and in 22/23 mice with a hematoma the ostium of the left suprarenal artery had ruptured. Supraceliac diameters at baseline were significantly lower for mice that did not develop an intramural hematoma, and the formation of a false channel within that intramural hematoma depended on the location, rather than the length, of the medial tear. Based on our observations we propose an elaborate hypothesis that explains how aortic side branches (i) affect the initiation and propagation of medial tears and the subsequent adventitial dissection and (ii) affect the variability in shape of dissecting aneurysms. This hypothesis was partially validated through the live visualization of a dissecting aneurysm that formed during micro-CT imaging, and led us to the conclusion that angiotensin II-infused mice are more clinically relevant for the study of aortic dissections than for the study of abdominal aortic aneurysms.

Structural elaboration in police organizations: an exploration

PurposeThe current research explores the structural elaboration of municipal American police organizations, specifically, the structural complexity of police organizations and its relationship to time. The purpose of this paper is to describe and test essential elements of the structural elaboration hypothesis.Design/methodology/approachThe authors explore the structural elaboration hypothesis utilizing a sample of 219 large police departments across the USA. Data are drawn from multiple waves of the Law Enforcement Management and Administrative Statistics survey and are analyzed using tobit and OLS regression techniques.FindingsWhile there is some evidence that police departments are becoming more elaborate, little evidence for the structural elaboration hypothesis as a function of time is found.Originality/valueThis project is the first to specifically explore the structural elaboration hypothesis across multiple time points. Additionally, results highlight structural trends across a panel of large American police organizations and provide potential explanations for changes. Suggestions for large-scale policing data collection are also provided.

An eye‐movement analysis of the refutation effect in reading science text

AbstractIn this study, we used eye‐tracking methodology for deeper understanding of the refutation text effect on online text comprehension. A refutation text acknowledges the reader's alternative conceptions about a phenomenon, refutes them and presents the correct conceptions. We tested two hypotheses about its facilitation effect: the coherence hypothesis (refutation text is more coherent than standard text, thus facilitating comprehension) and the elaboration hypothesis (refutation text involves deeper processing, thus facilitating comprehension). Forty university students read one refutation text and one non‐refutation text about two science topics. Offline data confirmed that refutation text readers recall more scientific facts than non‐refutation text readers. Online eye‐tracking measures revealed both an increase and a decrease in reading time in response to the refutation statements. Topic‐medial text sentences with the correct science facts were fixated for a shorter time when first encountered in the refutation text. Refutation statements, however, increased integrative processing at the end of each text paragraph, as indexed by longer look‐back fixation times on topic‐final sentences with the science concepts, as well as longer look‐back fixation times directed to the refutation statements. These findings support the elaboration hypothesis and are discussed in the light of current accounts of the refutation effect for theory development and educational practice.Lay DescriptionWhat is already known about this topic:Science texts are often challenging to read, especially when the reader has misconceptions about the topicand must undergo conceptual‐change learning in order to successfully comprehend the text.A specific type of text, therefutation text, mayact as a powerful resource in facilitating conceptual change, but findings from process‐oriented investigations have been inconclusive with respect to its efficacy in this regard.What this paper adds:Refutation statements lead to faster processing of scientific facts that contradict commonly held misconceptions during the first‐pass reading.Refutation statements also encourage readers' later integrative processing during rereading,to monitor and ensure resolution of the conflict between their own conceptions and the conceptual information contained within the text.Implications for practice and/or policy:Immediate introduction of new science concepts in an expository text may not benefit readers' comprehension when they have existing misconceptions within the relevant knowledge domain.The use of sentences explicitly refuting readers' misconceptions has the potential to induce and sustain the conscious and deliberate processing that is required for them to become aware of the conceptual conflict, increasing their likelihood of resolving it.Update made on 05 November 2016, after first online publication: Since the publication of this article, a Practitioner Notes section has been implemented for this journal. This article has been updated with the Practitioner Notes section.

Simple Learned Weighted Sums of Inferior Temporal Neuronal Firing Rates Accurately Predict Human Core Object Recognition Performance.

To go beyond qualitative models of the biological substrate of object recognition, we ask: can a single ventral stream neuronal linking hypothesis quantitatively account for core object recognition performance over a broad range of tasks? We measured human performance in 64 object recognition tests using thousands of challenging images that explore shape similarity and identity preserving object variation. We then used multielectrode arrays to measure neuronal population responses to those same images in visual areas V4 and inferior temporal (IT) cortex of monkeys and simulated V1 population responses. We tested leading candidate linking hypotheses and control hypotheses, each postulating how ventral stream neuronal responses underlie object recognition behavior. Specifically, for each hypothesis, we computed the predicted performance on the 64 tests and compared it with the measured pattern of human performance. All tested hypotheses based on low- and mid-level visually evoked activity (pixels, V1, and V4) were very poor predictors of the human behavioral pattern. However, simple learned weighted sums of distributed average IT firing rates exactly predicted the behavioral pattern. More elaborate linking hypotheses relying on IT trial-by-trial correlational structure, finer IT temporal codes, or ones that strictly respect the known spatial substructures of IT ("face patches") did not improve predictive power. Although these results do not reject those more elaborate hypotheses, they suggest a simple, sufficient quantitative model: each object recognition task is learned from the spatially distributed mean firing rates (100 ms) of ∼60,000 IT neurons and is executed as a simple weighted sum of those firing rates. Significance statement: We sought to go beyond qualitative models of visual object recognition and determine whether a single neuronal linking hypothesis can quantitatively account for core object recognition behavior. To achieve this, we designed a database of images for evaluating object recognition performance. We used multielectrode arrays to characterize hundreds of neurons in the visual ventral stream of nonhuman primates and measured the object recognition performance of >100 human observers. Remarkably, we found that simple learned weighted sums of firing rates of neurons in monkey inferior temporal (IT) cortex accurately predicted human performance. Although previous work led us to expect that IT would outperform V4, we were surprised by the quantitative precision with which simple IT-based linking hypotheses accounted for human behavior.

Inconsistency effects in source memory and compensatory schema-consistent guessing

The attention-elaboration hypothesis of memory for schematically unexpected information predicts better source memory for unexpected than expected sources. In three source-monitoring experiments, the authors tested the occurrence of an inconsistency effect in source memory. Participants were presented with items that were schematically either very expected or very unexpected for their source. Multinomial processing tree models were used to separate source memory, item memory, and guessing bias. Results show an inconsistency effect in source memory accompanied by a compensatory schema-consistent guessing bias when expectancy strength is high, that is, when items are very expected or very unexpected for their source.

Can the memory enhancement of the survival judgment task be explained by the elaboration hypothesis?: Evidence from a memory load paradigm1

AbstractMany reports have described a survival judgment task that requires participants to judge words according to their relevance to a survival situation, eliciting better recall than that obtained in other judgment tasks (e.g., semantic or self‐judgment tasks). Two explanatory hypotheses (the adaptive hypothesis and the elaboration hypothesis) have been proposed. Here we used the memory load paradigm to investigate whether the adaptive hypothesis or the combination hypothesis can better account for the memory enhancement of the survival judgment task. We used a survival judgment task and an autobiographical recall task with the condition of no memory load or memory load. The 48 participants performed four encoding conditions (memory load—survival, no memory load—survival, memory load—autobiographical, and no memory load—autobiographical). The results showed that memory enhancement of the survival judgment task occurred only in the no memory load condition, but not in the memory load condition. Our results support the elaboration hypothesis. We also discuss the validity of the elaboration hypothesis and future directions to be pursued in this research field.

The advantage of decomposing elaborate hypotheses on covariance matrices into conditionally independent hypotheses in building near-exact distributions for the test statistics

The aim of this paper is to show how the decomposition of elaborate hypotheses on the structure of covariance matrices into conditionally independent simpler hypotheses, by inducing the factorization of the overall test statistic into a product of several independent simpler test statistics, may be used to obtain near-exact distributions for the overall test statistics, even in situations where asymptotic distributions are not available in the literature and adequately fit ones are not easy to obtain.

Arousal, valence, and memory for detail

A common finding in the emotion‐memory literature is that memory is enhanced for positively arousing stimuli and negatively arousing stimuli relative to neutral stimuli. We tested the notion that post‐stimulus elaboration is responsible for these effects. Post‐stimulus elaboration refers to the process of thinking about an event (after its offset) more frequently or more in‐depth. We tested the hypothesis by presenting participants with 36 slides depicting events that varied in arousal (low and high) and valence (positive and negative). The opportunity for elaboration was manipulated by requiring participants, during the inter‐slide interval, to complete addition problems, simply view the addition problems, or view a blank slide. Cued recall memory was tested for central and background details. Based on the post‐stimulus elaboration hypothesis it was expected that the greatest memory decline would occur for the central details of negatively and positively arousing slides when participants were required to complete addition problems (i.e., a distractor task × arousal × detail interaction). Contrary to the hypothesis, we found that filling the inter‐slide interval with a distractor task decreased memory for negative stimuli compared to positive stimuli. This effect was independent of arousal. We also found that arousal increased central detail memory for positive and negative stimuli and background detail memory for positive stimuli but not for negative stimuli. This interaction was explained on the basis of pre‐attentive encoding and cue utilisation. It was concluded that in order to understand the complex relationship between emotion and memory, future studies should include, as a minimum, the variables of valence, arousal, and detail.

Gene expression profile of cardiomyocytes in hypertrophic heart induced by continuous norepinephrine infusion in the rats.

Catecholamines play an important role in the development of cardiac hypertrophy. To observe cardiomyocyte-specific gene expression changes induced by catecholamines in vivo, left ventricular cardiomyocytes were isolated from male Sprague-Dawley rats after continuous infusion of norepinephrine (NE; 0.2 mg/kg per hour intravenously) for 0.5, 1, 2, 3 and 7 days. The gene expression profiles of these cells during different NE infusion stages were assessed by using a cDNA microarray, and the microarray data were further analyzed by a clustering method. Cardiac hypertrophy was induced upon continuous NE infusion, with the peak at 3 days. Meanwhile, manifest changes in gene expression profile within cardiomyocytes over the time course were revealed, most of the genes never having been reported to be involved in cardiac hypertrophy. The number of genes displaying differential expression also peaked at the middle stage of infusion (2-3 days), and the majority of the signaling molecules were found differentially expressed mainly at this stage, including phosphatidylinositol 3-kinase, calcium/calmodulin-dependent protein kinase II and non-receptor tyrosine kinases, etc. The tumor suppressor p53 was found up-regulated at very early (0.5 days) and late stages (7 days) of NE infusion. Self-organization clustering analysis revealed subsets of coordinate regulated genes. One set consisted of several enzymes involved in energy metabolism, including carnitine octanoyltransferase, ATP synthase subunit c, pancreatic lipase and glycogen phosphorylase, possessing a similar expression pattern with a rapidly elevated expression level at the early stage of NE infusion. This is the first study to provide transcriptional information for cardiomyocytes, a single cell type, in the heart during the development of cardiac hypertrophy in vivo, and may provide accurate clues to elaborate hypotheses about the evolution of this pathology.

Memory for negatively arousing and neutral pictorial stimuli using a repeated testing paradigm

The relationship between negatively arousing pictorial stimuli and memory was investigated using a repeated testing paradigm. Based on the previous literature, it was assumed that the superior memory for negatively arousing material was due to elaboration. Therefore, we hypothesised that negatively arousing material would produce more hypermnesia than neutral material because of the increased elaboration associated with negatively arousing stimuli. A total of 160 participants viewed negatively arousing or neutral slides for either 1 second or 5 seconds and completed three free recall tests. During the inter-test intervals, participants worked on a filler task or sat quietly. The results showed superior memory for negatively arousing slides over neutral slides, and an increase in memory across tests for the arousal condition but not for the neutral condition. The results did not provide strong support for the elaboration hypothesis.

Categorizing archaeological finds: the funerary material of Queen Hetepheres I at Giza

The undisturbed shaft deposit G7000x in front of the Great Pyramid at Giza has been regarded as the tomb of Queen Hetepheres I, even though it did not contain a mummy. The absence of the mummy has posed problems for the finds categorization as a tomb and has given rise to elaborate hypotheses. As shown here, these difficulties can be largely eliminated if the find is understood as a funerary deposit and not a tomb. The new categorization is also significant for the understanding of Old Kingdom funerary practices.

Pregnant: And Still Macho

One-half of the human race may find the idea more interesting than the other half does, but regardless, there's been plenty of speculation on what the world would be like if males were the ones who got pregnant. The more elaborate hypotheses— about warp-speed progress in obstetrics or Tiger Woods endorsing maternity clothes—have yet to receive rigorous testing. However, some of the basic theories of sexual behavior and sexual selection are getting attention thanks to a burst of new studies in the topsy-turvy social world of the seahorse.

Layered murein revisited: a fundamentally new concept of bacterial cell wall structure, biogenesis and function.

The classical concept of the architecture of microbial murein assumes cross-linked glycan chains to be arranged in horizontal layers outside of the plasma membrane. It necessitates elaborate hypotheses to explain processes such as the biosynthesis, growth and division of the bacterial cell wall and provides no explanation for transenvelope macromolecular transport. Moreover, this model is difficult to reconcile with a number of basic chemical and electron microscopical data. According to a fundamentally distinct concept which is presented here, glycan strands in the microbial wall run perpendicular to the plasma membrane, each strand being cross-linked by peptide bridges with four other strands. This arrangement allows the formation of a structured matrix pierced with ordered ionophoric channels potentially harboring either lipoprotein or teichoic (lipoteichoic) acid molecules in Gram-negative and Gram-positive bacteria, respectively. New wall structures are synthesized in toto emerging from the cytoplasmic membrane as a condensed gel-like network below the old wall without being covalently attached to it, expanding due to inherent elasticity as the old wall is lyzed. This model reflects published genetic and biochemical data and offers a simple explanation for peptidoglycan biogenesis. As the biosynthesis is terminated by enzymic cleavage of all glycan strands, murein is irreversibly released from the membrane. The murein detachment prepares the membrane for de novo assembly of both the new wall synthesis machinery and the multicomponent factory for protein, DNA and phospholipid transfer. Being assembled in parallel, both new murein and the traffic complexes grow from the membrane together. This concept eliminates the necessity for the traffic complexes to penetrate intact murein. In the process of simultaneous assembly, the expanding murein functions as a lifting platform driven by the force of turgor pressure, transporting macromolecules through the perisplasmic space.

Children's comprehension and production of idioms: the role of context and familiarity.

Several studies have argued that children under the ages of nine or ten years rarely comprehend figurative language and therefore interpret it literally. Cacciari & Levorato (1989) showed that when idioms are presented within a rich informational environment, children are able to grasp the figurative sense at the age of seven, and also that children are less able to produce idioms than to comprehend them. In three experiments involving 264 children (whose age ranged from 6;9 to 11;9), we contrasted this global elaboration hypothesis with a partially alternative one, the acquisition via exposure hypothesis, according to which the frequency of exposure of children to idioms is the main factor explaining their acquisition and production. Results showed that familiarity (i.e. frequency of exposure) plays a minor role and only for children who are not yet able to use contextual information. Familiarity per se does not adequately explain how children acquire a figurative competence. A tentative model is proposed in order to account for figurative competence acquisition.

Accumulation of acyl-enzyme in dd-peptidase-catalysed reactions with analogues of peptide substrates

Thioester substrates can be used to study the hydrolysis and transfer reactions catalysed by beta-lactamases and DD-peptidases. With the latter enzymes, accumulation of the acyl-enzyme can be detected directly. The efficiency of various amines as acceptor substrates was in excellent agreement with previous results obtained with peptide substrates of the DD-peptidases. The results indicated the presence of a specific binding site for the acceptor substrates. Although most of the results agreed well with a simple partition model, more elaborate hypotheses will be needed to account for all the data presented.