Other people as means to a safe end: vicarious extinction blocks the return of learned fear.

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Golkar, Armita; Selbing, Ida; Flygare, Oskar; Ohman, Arne; Olsson, Andreas

2013-11-01

Information about what is dangerous and safe in the environment is often transferred from other individuals through social forms of learning, such as observation. Past research has focused on the observational, or vicarious, acquisition of fears, but little is known about how social information can promote safety learning. To address this issue, we studied the effects of vicarious-extinction learning on the recovery of conditioned fear. Compared with a standard extinction procedure, vicarious extinction promoted better extinction and effectively blocked the return of previously learned fear. We confirmed that these effects could not be attributed to the presence of a learning model per se but were specifically driven by the model's experience of safety. Our results confirm that vicarious and direct emotional learning share important characteristics but that social-safety information promotes superior down-regulation of learned fear. These findings have implications for emotional learning, social-affective processes, and clinical practice.

Vicarious learning: a review of the literature.

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Roberts, Debbie

2010-01-01

Experiential learning theory stresses the primacy of personal experience and the literature suggests that direct clinical experience is required in order for learning to take place. However, raw or first hand experience may not be the only mechanisms by which students engage in experiential learning. There is a growing body of literature within higher education which suggests that students are able to use another's experience to learn: vicarious learning. This literature review aims to outline vicarious learning within a nursing context. Many of the studies regarding vicarious learning are situated within Higher Education in general, however, within the United States these relate more specifically to nursing students. The literature indicates the increasing global interest in this area. This paper reveals that whilst the literature offers a number of examples illustrating how vicarious learning takes place, opinion on the role of the lecturer is divided and requires further exploration and clarification. The implications for nurse education are discussed.

Vicarious experience affects patients' treatment preferences for depression.

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Seth A Berkowitz

Full Text Available Depression is common in primary care but often under-treated. Personal experiences with depression can affect adherence to therapy, but the effect of vicarious experience is unstudied. We sought to evaluate the association between a patient's vicarious experiences with depression (those of friends or family and treatment preferences for depressive symptoms.We sampled 1054 English and/or Spanish speaking adult subjects from July through December 2008, randomly selected from the 2008 California Behavioral Risk Factor Survey System, regarding depressive symptoms and treatment preferences. We then constructed a unidimensional scale using item analysis that reflects attitudes about antidepressant pharmacotherapy. This became the dependent variable in linear regression analyses to examine the association between vicarious experiences and treatment preferences for depressive symptoms.Our sample was 68% female, 91% white, and 13% Hispanic. Age ranged from 18-94 years. Mean PHQ-9 score was 4.3; 14.5% of respondents had a PHQ-9 score >9.0, consistent with active depressive symptoms. Analyses controlling for current depression symptoms and socio-demographic factors found that in patients both with (coefficient 1.08, p = 0.03 and without (coefficient 0.77, p = 0.03 a personal history of depression, having a vicarious experience (family and friend, respectively with depression is associated with a more favorable attitude towards antidepressant medications.Patients with vicarious experiences of depression express more acceptance of pharmacotherapy. Conversely, patients lacking vicarious experiences of depression have more negative attitudes towards antidepressants. When discussing treatment with patients, clinicians should inquire about vicarious experiences of depression. This information may identify patients at greater risk for non-adherence and lead to more tailored patient-specific education about treatment.

Vicarious Reinforcement In Rhesus Macaques (Macaca mulatta

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Steve W. C. Chang

2011-03-01

Full Text Available What happens to others profoundly influences our own behavior. Such other-regarding outcomes can drive observational learning, as well as motivate cooperation, charity, empathy, and even spite. Vicarious reinforcement may serve as one of the critical mechanisms mediating the influence of other-regarding outcomes on behavior and decision-making in groups. Here we show that rhesus macaques spontaneously derive vicarious reinforcement from observing rewards given to another monkey, and that this reinforcement can motivate them to subsequently deliver or withhold rewards from the other animal. We exploited Pavlovian and instrumental conditioning to associate rewards to self (M1 and/or rewards to another monkey (M2 with visual cues. M1s made more errors in the instrumental trials when cues predicted reward to M2 compared to when cues predicted reward to M1, but made even more errors when cues predicted reward to no one. In subsequent preference tests between pairs of conditioned cues, M1s preferred cues paired with reward to M2 over cues paired with reward to no one. By contrast, M1s preferred cues paired with reward to self over cues paired with reward to both monkeys simultaneously. Rates of attention to M2 strongly predicted the strength and valence of vicarious reinforcement. These patterns of behavior, which were absent in nonsocial control trials, are consistent with vicarious reinforcement based upon sensitivity to observed, or counterfactual, outcomes with respect to another individual. Vicarious reward may play a critical role in shaping cooperation and competition, as well as motivating observational learning and group coordination in rhesus macaques, much as it does in humans. We propose that vicarious reinforcement signals mediate these behaviors via homologous neural circuits involved in reinforcement learning and decision-making.

Vicarious reinforcement in rhesus macaques (macaca mulatta).

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Chang, Steve W C; Winecoff, Amy A; Platt, Michael L

2011-01-01

What happens to others profoundly influences our own behavior. Such other-regarding outcomes can drive observational learning, as well as motivate cooperation, charity, empathy, and even spite. Vicarious reinforcement may serve as one of the critical mechanisms mediating the influence of other-regarding outcomes on behavior and decision-making in groups. Here we show that rhesus macaques spontaneously derive vicarious reinforcement from observing rewards given to another monkey, and that this reinforcement can motivate them to subsequently deliver or withhold rewards from the other animal. We exploited Pavlovian and instrumental conditioning to associate rewards to self (M1) and/or rewards to another monkey (M2) with visual cues. M1s made more errors in the instrumental trials when cues predicted reward to M2 compared to when cues predicted reward to M1, but made even more errors when cues predicted reward to no one. In subsequent preference tests between pairs of conditioned cues, M1s preferred cues paired with reward to M2 over cues paired with reward to no one. By contrast, M1s preferred cues paired with reward to self over cues paired with reward to both monkeys simultaneously. Rates of attention to M2 strongly predicted the strength and valence of vicarious reinforcement. These patterns of behavior, which were absent in non-social control trials, are consistent with vicarious reinforcement based upon sensitivity to observed, or counterfactual, outcomes with respect to another individual. Vicarious reward may play a critical role in shaping cooperation and competition, as well as motivating observational learning and group coordination in rhesus macaques, much as it does in humans. We propose that vicarious reinforcement signals mediate these behaviors via homologous neural circuits involved in reinforcement learning and decision-making.

Vicarious learning and the development of fears in childhood.

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Askew, Chris; Field, Andy P

2007-11-01

Vicarious learning has long been assumed to be an indirect pathway to fear; however, there is only retrospective evidence that children acquire fears in this way. In two experiments, children (aged 7-9 years) were exposed to pictures of novel animals paired with pictures of either scared, happy or no facial expressions to see the impact on their fear cognitions and avoidance behavior about the animals. In Experiment 1, directly (self-report) and indirectly measured (affective priming) fear attitudes towards the animals changed congruent with the facial expressions with which these were paired. The indirectly measured fear beliefs persisted up to 3 months. Experiment 2 showed that children took significantly longer to approach a box they believed to contain an animal they had previously seen paired with scared faces. These results support theories of fear acquisition that suppose that vicarious learning affects cognitive and behavioral fear emotion, and suggest possibilities for interventions to weaken fear acquired in this way.

Campaign for vicarious calibration of SumbandilaSat in Argentina

CSIR Research Space (South Africa)

Vhengani, LM

2011-07-01

Full Text Available assessment, they are also calibrated post-launch. Various post-launch techniques exist including cross-sensor, solar, lunar and vicarious calibration. Vicarious calibration relies on in-situ measurements of surface reflectance and atmospheric transmittance...

Vicarious pain experiences while observing another in pain: an experimental approach

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Sophie eVandenbroucke

2013-06-01

Full Text Available Objective: This study aimed at developing an experimental paradigm to assess vicarious pain experiences. We further explored the putative moderating role of observer’s characteristics such as hypervigilance for pain and dispositional empathy. Methods: Two experiments are reported using a similar procedure. Undergraduate students were selected based upon whether they reported vicarious pain in daily life, and categorized into a pain responder group or a comparison group. Participants were presented a series of videos showing hands being pricked whilst receiving occasionally pricking (electrocutaneous stimuli themselves. In congruent trials, pricking and visual stimuli were applied to the same spatial location. In incongruent trials, pricking and visual stimuli were in the opposite spatial location. Participants were required to report on which location they felt a pricking sensation. Of primary interest was the effect of viewing another in pain upon vicarious pain errors, i.e., the number of trials in which an illusionary sensation was reported. Furthermore, we explored the effect of individual differences in hypervigilance to pain, dispositional empathy and the rubber hand illusion (RHI upon vicarious pain errors. Results: Results of both experiments indicated that the number of vicarious pain errors was overall low. In line with expectations, the number of vicarious pain errors was higher in the pain responder group than in the comparison group. Self-reported hypervigilance for pain lowered the probability of reporting vicarious pain errors in the pain responder group, but dispositional empathy and the RHI did not. Conclusion: Our paradigm allows measuring vicarious pain experiences in students. However, the prevalence of vicarious experiences of pain is low, and only a small percentage of participants display the phenomenon. It remains however unknown which variables affect its occurrence.

Vicarious Acquisition Of Learned Helplessness

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And Others; DeVellis, Robert F.

1978-01-01

Reports a study conducted to determine whether individuals who observed others experiencing noncontingency would develop learned helplessness vicariously. Subjects were 75 college female undergraduates. (MP)

Behavioural and neurobiological foundations of vicarious processing

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Lockwood, P. L.

2015-01-01

Empathy can be broadly defined as the ability to vicariously experience and to understand the affect of other people. This thesis will argue that such a capacity for vicarious processing is fundamental for successful social-cognitive ability and behaviour. To this end, four outstanding research questions regarding the behavioural and neural basis of empathy are addressed 1) can empathy be dissected into different components and do these components differentially explain individual differences...

Learning to fear a second-order stimulus following vicarious learning

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Reynolds, G; Field, AP; Askew, C

2015-01-01

Vicarious fear learning refers to the acquisition of fear via observation of the fearful responses of others. The present study aims to extend current knowledge by exploring whether second-order vicarious fear learning can be demonstrated in children. That is, whether vicariously learnt fear responses for one stimulus can be elicited in a second stimulus associated with that initial stimulus. Results demonstrated that children’s (5–11 years) fear responses for marsupials and caterpillars incr...

Explaining Self and Vicarious Reactance: A Process Model Approach.

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Sittenthaler, Sandra; Jonas, Eva; Traut-Mattausch, Eva

2016-04-01

Research shows that people experience a motivational state of agitation known as reactance when they perceive restrictions to their freedoms. However, research has yet to show whether people experience reactance if they merely observe the restriction of another person's freedom. In Study 1, we activated realistic vicarious reactance in the laboratory. In Study 2, we compared people's responses with their own and others' restrictions and found the same levels of experienced reactance and behavioral intentions as well as aggressive tendencies. We did, however, find differences in physiological arousal: Physiological arousal increased quickly after participants imagined their own freedom being restricted, but arousal in response to imagining a friend's freedom being threatened was weaker and delayed. In line with the physiological data, Study 3's results showed that self-restrictions aroused more emotional thoughts than vicarious restrictions, which induced more cognitive responses. Furthermore, in Study 4a, a cognitive task affected only the cognitive process behind vicarious reactance. In contrast, in Study 4b, an emotional task affected self-reactance but not vicarious reactance. We propose a process model explaining the emotional and cognitive processes of self- and vicarious reactance. © 2016 by the Society for Personality and Social Psychology, Inc.

Types of vicarious learning experienced by pre-dialysis patients

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Kate McCarthy

2015-04-01

Full Text Available Objective: Haemodialysis and peritoneal dialysis renal replacement treatment options are in clinical equipoise, although the cost of haemodialysis to the National Health Service is £16,411/patient/year greater than peritoneal dialysis. Treatment decision-making takes place during the pre-dialysis year when estimated glomerular filtration rate drops to between 15 and 30 mL/min/1.73 m2. Renal disease can be familial, and the majority of patients have considerable health service experience when they approach these treatment decisions. Factors affecting patient treatment decisions are currently unknown. The objective of this article is to explore data from a wider study in specific relation to the types of vicarious learning experiences reported by pre-dialysis patients. Methods: A qualitative study utilised unstructured interviews and grounded theory analysis during the participant’s pre-dialysis year. The interview cohort comprised 20 pre-dialysis participants between 24 and 80 years of age. Grounded theory design entailed thematic sampling and analysis, scrutinised by secondary coding and checked with participants. Participants were recruited from routine renal clinics at two local hospitals when their estimated glomerular filtration rate was between 15 and 30 mL/min/1.73 m2. Results: Vicarious learning that contributed to treatment decision-making fell into three main categories: planned vicarious leaning, unplanned vicarious learning and historical vicarious experiences. Conclusion: Exploration and acknowledgement of service users’ prior vicarious learning, by healthcare professionals, is important in understanding its potential influences on individuals’ treatment decision-making. This will enable healthcare professionals to challenge heuristic decisions based on limited information and to encourage analytic thought processes.

Types of vicarious learning experienced by pre-dialysis patients.

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McCarthy, Kate; Sturt, Jackie; Adams, Ann

2015-01-01

Haemodialysis and peritoneal dialysis renal replacement treatment options are in clinical equipoise, although the cost of haemodialysis to the National Health Service is £16,411/patient/year greater than peritoneal dialysis. Treatment decision-making takes place during the pre-dialysis year when estimated glomerular filtration rate drops to between 15 and 30 mL/min/1.73 m(2). Renal disease can be familial, and the majority of patients have considerable health service experience when they approach these treatment decisions. Factors affecting patient treatment decisions are currently unknown. The objective of this article is to explore data from a wider study in specific relation to the types of vicarious learning experiences reported by pre-dialysis patients. A qualitative study utilised unstructured interviews and grounded theory analysis during the participant's pre-dialysis year. The interview cohort comprised 20 pre-dialysis participants between 24 and 80 years of age. Grounded theory design entailed thematic sampling and analysis, scrutinised by secondary coding and checked with participants. Participants were recruited from routine renal clinics at two local hospitals when their estimated glomerular filtration rate was between 15 and 30 mL/min/1.73 m(2). Vicarious learning that contributed to treatment decision-making fell into three main categories: planned vicarious leaning, unplanned vicarious learning and historical vicarious experiences. Exploration and acknowledgement of service users' prior vicarious learning, by healthcare professionals, is important in understanding its potential influences on individuals' treatment decision-making. This will enable healthcare professionals to challenge heuristic decisions based on limited information and to encourage analytic thought processes.

The role of empathy in experiencing vicarious anxiety.

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Shu, Jocelyn; Hassell, Samuel; Weber, Jochen; Ochsner, Kevin N; Mobbs, Dean

2017-08-01

With depictions of others facing threats common in the media, the experience of vicarious anxiety may be prevalent in the general population. However, the phenomenon of vicarious anxiety-the experience of anxiety in response to observing others expressing anxiety-and the interpersonal mechanisms underlying it have not been fully investigated in prior research. In 4 studies, we investigate the role of empathy in experiencing vicarious anxiety, using film clips depicting target victims facing threats. In Studies 1 and 2, trait emotional empathy was associated with greater self-reported anxiety when observing target victims, and with perceiving greater anxiety to be experienced by the targets. Study 3 extended these findings by demonstrating that trait empathic concern-the tendency to feel concern and compassion for others-was associated with experiencing vicarious anxiety, whereas trait personal distress-the tendency to experience distress in stressful situations-was not. Study 4 manipulated state empathy to establish a causal relationship between empathy and experience of vicarious anxiety. Participants who took an empathic perspective when observing target victims, as compared to those who took an objective perspective using reappraisal-based strategies, reported experiencing greater anxiety, risk-aversion, and sleep disruption the following night. These results highlight the impact of one's social environment on experiencing anxiety, particularly for those who are highly empathic. In addition, these findings have implications for extending basic models of anxiety to incorporate interpersonal processes, understanding the role of empathy in social learning, and potential applications for therapeutic contexts. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

The Moderating Effects of Peer and Parental Support on the Relationship Between Vicarious Victimization and Substance Use

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Miller, Riane N.; Fagan, Abigail A.; Wright, Emily M.

2014-01-01

General strain theory (GST) hypothesizes that youth are more likely to engage in delinquency when they experience vicarious victimization, defined as knowing about or witnessing violence perpetrated against others, but that this relationship may be attenuated for those who receive social support from significant others. Based on prospective data from youth aged 8 to 17 participating in the Project on Human Development in Chicago Neighborhoods (PHDCN), this article found mixed support for thes...

Learning to fear a second-order stimulus following vicarious learning.

Science.gov (United States)

Reynolds, Gemma; Field, Andy P; Askew, Chris

2017-04-01

Vicarious fear learning refers to the acquisition of fear via observation of the fearful responses of others. The present study aims to extend current knowledge by exploring whether second-order vicarious fear learning can be demonstrated in children. That is, whether vicariously learnt fear responses for one stimulus can be elicited in a second stimulus associated with that initial stimulus. Results demonstrated that children's (5-11 years) fear responses for marsupials and caterpillars increased when they were seen with fearful faces compared to no faces. Additionally, the results indicated a second-order effect in which fear-related learning occurred for other animals seen together with the fear-paired animal, even though the animals were never observed with fearful faces themselves. Overall, the findings indicate that for children in this age group vicariously learnt fear-related responses for one stimulus can subsequently be observed for a second stimulus without it being experienced in a fear-related vicarious learning event. These findings may help to explain why some individuals do not recall involvement of a traumatic learning episode in the development of their fear of a specific stimulus.

Neural signals of vicarious extinction learning.

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Golkar, Armita; Haaker, Jan; Selbing, Ida; Olsson, Andreas

2016-10-01

Social transmission of both threat and safety is ubiquitous, but little is known about the neural circuitry underlying vicarious safety learning. This is surprising given that these processes are critical to flexibly adapt to a changeable environment. To address how the expression of previously learned fears can be modified by the transmission of social information, two conditioned stimuli (CS + s) were paired with shock and the third was not. During extinction, we held constant the amount of direct, non-reinforced, exposure to the CSs (i.e. direct extinction), and critically varied whether another individual-acting as a demonstrator-experienced safety (CS + vic safety) or aversive reinforcement (CS + vic reinf). During extinction, ventromedial prefrontal cortex (vmPFC) responses to the CS + vic reinf increased but decreased to the CS + vic safety This pattern of vmPFC activity was reversed during a subsequent fear reinstatement test, suggesting a temporal shift in the involvement of the vmPFC. Moreover, only the CS + vic reinf association recovered. Our data suggest that vicarious extinction prevents the return of conditioned fear responses, and that this efficacy is reflected by diminished vmPFC involvement during extinction learning. The present findings may have important implications for understanding how social information influences the persistence of fear memories in individuals suffering from emotional disorders. © The Author (2016). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Risk of vicarious trauma in nursing research: a focused mapping review and synthesis.

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Taylor, Julie; Bradbury-Jones, Caroline; Breckenridge, Jenna P; Jones, Christine; Herber, Oliver Rudolf

2016-10-01

To provide a snapshot of how vicarious trauma is considered within the published nursing research literature. Vicarious trauma (secondary traumatic stress) has been the focus of attention in nursing practice for many years. The most pertinent areas to invoke vicarious trauma in research have been suggested as abuse/violence and death/dying. What is not known is how researchers account for the risks of vicarious trauma in research. Focused mapping review and synthesis. Empirical studies meeting criteria for abuse/violence or death/dying in relevant Scopus ranked top nursing journals (n = 6) January 2009 to December 2014. Relevant papers were scrutinised for the extent to which researchers discussed the risk of vicarious trauma. Aspects of the studies were mapped systematically to a pre-defined template, allowing patterns and gaps in authors' reporting to be determined. These were synthesised into a coherent profile of current reporting practices and from this, a new conceptualisation seeking to anticipate and address the risk of vicarious trauma was developed. Two thousand five hundred and three papers were published during the review period, of which 104 met the inclusion criteria. Studies were distributed evenly by method (52 qualitative; 51 quantitative; one mixed methods) and by focus (54 abuse/violence; 50 death/dying). The majority of studies (98) were carried out in adult populations. Only two papers reported on vicarious trauma. The conceptualisation of vicarious trauma takes account of both sensitivity of the substantive data collected, and closeness of those involved with the research. This might assist researchers in designing ethical and protective research and foreground the importance of managing risks of vicarious trauma. Vicarious trauma is not well considered in research into clinically important topics. Our proposed framework allows for consideration of these so that precautionary measures can be put in place to minimise harm to staff. © 2016

Late Cretaceous vicariance in Gondwanan amphibians.

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Ines Van Bocxlaer

Full Text Available Overseas dispersals are often invoked when Southern Hemisphere terrestrial and freshwater organism phylogenies do not fit the sequence or timing of Gondwana fragmentation. We used dispersal-vicariance analyses and molecular timetrees to show that two species-rich frog groups, Microhylidae and Natatanura, display congruent patterns of spatial and temporal diversification among Gondwanan plates in the Late Cretaceous, long after the presumed major tectonic break-up events. Because amphibians are notoriously salt-intolerant, these analogies are best explained by simultaneous vicariance, rather than by oceanic dispersal. Hence our results imply Late Cretaceous connections between most adjacent Gondwanan landmasses, an essential concept for biogeographic and palaeomap reconstructions.

Information about the model's unconditioned stimulus and response in vicarious classical conditioning.

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Hygge, S

1976-06-01

Four groups with 16 observers each participated in a differential, vicarious conditioning experiment with skin conductance responses as the dependent variable. The information available to the observer about the model's unconditioned stimulus and response was varied in a 2 X 2 factorial design. Results clearly showed that information about the model's unconditioned stimulus (a high or low dB level) was not necessary for vicarious instigation, but that information about the unconditioned response (a high or low emotional aversiveness) was necessary. Data for conditioning of responses showed almost identical patterns to those for vicarious instigation. To explain the results, a distinction between factors necessary for the development and elicitation of vicariously instigated responses was introduced, and the effectiveness of information about the model's response on the elicitation of vicariously instigated responses was considered in terms of an expansion of Bandura's social learning theory.

The vicarious learning pathway to fear 40 years on.

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Askew, Chris; Field, Andy P

2008-10-01

Forty years on from the initial idea that fears could be learnt vicariously through observing other people's responses to a situation or stimulus, this review looks at the evidence for this theory as an explanatory model of clinical fear. First, we review early experimental evidence that fears can be learnt vicariously before turning to the evidence from both primate and human research that clinical fears can be acquired in this way. Finally, we review recent evidence from research on non-anxious children. Throughout the review we highlight problems and areas for future research. We conclude by exploring the likely underlying mechanisms in the vicarious learning of fear and the resulting clinical implications.

Vicarious retribution: the role of collective blame in intergroup aggression.

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Lickel, Brian; Miller, Norman; Stenstrom, Douglas M; Denson, Thomas F; Schmader, Toni

2006-01-01

We provide a new framework for understanding 1 aspect of aggressive conflict between groups, which we refer to as vicarious retribution. Vicarious retribution occurs when a member of a group commits an act of aggression toward the members of an outgroup for an assault or provocation that had no personal consequences for him or her but which did harm a fellow ingroup member. Furthermore, retribution is often directed at outgroup members who, themselves, were not the direct causal agents in the original attack against the person's ingroup. Thus, retribution is vicarious in that neither the agent of retaliation nor the target of retribution were directly involved in the original event that precipitated the intergroup conflict. We describe how ingroup identification, outgroup entitativity, and other variables, such as group power, influence vicarious retribution. We conclude by considering a variety of conflict reduction strategies in light of this new theoretical framework.

Stimulus fear-relevance and the vicarious learning pathway to childhood fears

OpenAIRE

Askew, C.; Dunne, G.; Ozdil, A.; Reynolds, G.; Field, A.P.

2013-01-01

Enhanced fear learning for fear-relevant stimuli has been demonstrated in procedures with adults in the laboratory. Three experiments investigated the effect of stimulus fear-relevance on vicarious fear learning in children (aged 6-11 years). Pictures of stimuli with different levels of fear-relevance (flowers, caterpillars, snakes, worms, and Australian marsupials) were presented alone or together with scared faces. In line with previous studies, children's fear beliefs and avoidance prefere...

Effects of Competition on Students' Self-Efficacy in Vicarious Learning

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Chan, Joanne C. Y.; Lam, Shui-fong

2008-01-01

Background: Vicarious learning is one of the fundamental sources of self-efficacy that is frequently employed in educational settings. However, little research has investigated the effects of competition on students' writing self-efficacy when they engage in vicarious learning. Aim: This study compared the effects of competitive and…

Vicarious motor activation during action perception: beyond correlational evidence

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Alessio eAvenanti

2013-05-01

Full Text Available Neurophysiological and imaging studies have shown that seeing the actions of other individuals brings about the vicarious activation of motor regions involved in performing the same actions. While this suggests a simulative mechanism mediating the perception of others’ actions, one cannot use such evidence to make inferences about the functional significance of vicarious activations. Indeed, a central aim in social neuroscience is to comprehend how vicarious activations allow the understanding of other people’s behavior, and this requires to use stimulation or lesion methods to establish causal links from brain activity to cognitive functions. In the present work we review studies investigating the effects of transient manipulations of brain activity or stable lesions in the motor system on individuals’ ability to perceive and understand the actions of others. We conclude there is now compelling evidence that neural activity in the motor system is critical for such cognitive ability. More research using causal methods, however, is needed in order to disclose the limits and the conditions under which vicarious activations are required to perceive and understand actions of others as well as their emotions and somatic feelings.

Vicarious learning from human models in monkeys.

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Falcone, Rossella; Brunamonti, Emiliano; Genovesio, Aldo

2012-01-01

We examined whether monkeys can learn by observing a human model, through vicarious learning. Two monkeys observed a human model demonstrating an object-reward association and consuming food found underneath an object. The monkeys observed human models as they solved more than 30 learning problems. For each problem, the human models made a choice between two objects, one of which concealed a piece of apple. In the test phase afterwards, the monkeys made a choice of their own. Learning was apparent from the first trial of the test phase, confirming the ability of monkeys to learn by vicarious observation of human models.

My partner's stories: relationships between personal and vicarious life stories within romantic couples.

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Panattoni, Katherine; Thomsen, Dorthe Kirkegaard

2018-06-12

In this paper, we examined relationships and differences between personal and vicarious life stories, i.e., the life stories one knows of others. Personal and vicarious life stories of both members of 51 young couples (102 participants), based on McAdams' Life Story Interview (2008), were collected. We found significant positive relationships between participants' personal and vicarious life stories on agency and communion themes and redemption sequences. We also found significant positive relationships between participants' vicarious life stories about their partners and those partners' personal life stories on agency and communion, but not redemption. Furthermore, these relationships were not explained by similarity between couples' two personal life stories, as no associations were found between couples' personal stories on agency, communion and redemption. These results suggest that the way we construct the vicarious life stories of close others may reflect how we construct our personal life stories.

Vicarious learning from human models in monkeys.

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Rossella Falcone

Full Text Available We examined whether monkeys can learn by observing a human model, through vicarious learning. Two monkeys observed a human model demonstrating an object-reward association and consuming food found underneath an object. The monkeys observed human models as they solved more than 30 learning problems. For each problem, the human models made a choice between two objects, one of which concealed a piece of apple. In the test phase afterwards, the monkeys made a choice of their own. Learning was apparent from the first trial of the test phase, confirming the ability of monkeys to learn by vicarious observation of human models.

Active, Passive, and Vicarious Desensitization

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Denney, Douglas R.

1974-01-01

Two variations of desensitization therapy for reducing test anxiety were studied, active desensitization in which the client describes his visualizations of the scenes and vicarious desensitization in which the client merely observes the desensitization treatment of another test anxious client. The relaxation treatment which emphasized application…

Beyond Vicary's fantasies: The impact of subliminal priming and brand choice

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Karremans, J.C.T.M.; Stroebe, W.; Claus, J.

2006-01-01

With his claim to have increased sales of Coca Cola and popcorn in a movie theatre through subliminal messages flashed on the screen, James Vicary raised the possibility of subliminal advertising. Nobody has ever replicated Vicary's findings and his study was a hoax. This article reports two

Promoting Constructive Activities that Support Vicarious Learning during Computer-Based Instruction

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Gholson, Barry; Craig, Scotty D.

2006-01-01

This article explores several ways computer-based instruction can be designed to support constructive activities and promote deep-level comprehension during vicarious learning. Vicarious learning, discussed in the first section, refers to knowledge acquisition under conditions in which the learner is not the addressee and does not physically…

Vicarious learning revisited: a contemporary behavior analytic interpretation.

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Masia, C L; Chase, P N

1997-03-01

Beginning in the 1960s, social learning theorists argued that behavioral learning principles could not account for behavior acquired through observation. Such a viewpoint is still widely held today. This rejection of behavioral principles in explaining vicarious learning was based on three phenomena: (1) imitation that occurred without direct reinforcement of the observer's behavior; (2) imitation that occurred after a long delay following modeling; and (3) a greater probability of imitation of the model's reinforced behavior than of the model's nonreinforced or punished behavior. These observations convinced social learning theorists that cognitive variables were required to explain behavior. Such a viewpoint has progressed aggressively, as evidenced by the change in name from social learning theory to social cognitive theory, and has been accompanied by the inclusion of information-processing theory. Many criticisms of operant theory, however, have ignored the full range of behavioral concepts and principles that have been derived to account for complex behavior. This paper will discuss some problems with the social learning theory explanation of vicarious learning and provide an interpretation of vicarious learning from a contemporary behavior analytic viewpoint.

Inhibition of vicariously learned fear in children using positive modeling and prior exposure.

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Askew, Chris; Reynolds, Gemma; Fielding-Smith, Sarah; Field, Andy P

2016-02-01

One of the challenges to conditioning models of fear acquisition is to explain how different individuals can experience similar learning events and only some of them subsequently develop fear. Understanding factors moderating the impact of learning events on fear acquisition is key to understanding the etiology and prevention of fear in childhood. This study investigates these moderators in the context of vicarious (observational) learning. Two experiments tested predictions that the acquisition or inhibition of fear via vicarious learning is driven by associative learning mechanisms similar to direct conditioning. In Experiment 1, 3 groups of children aged 7 to 9 years received 1 of 3 inhibitive information interventions-psychoeducation, factual information, or no information (control)-prior to taking part in a vicarious fear learning procedure. In Experiment 2, 3 groups of children aged 7 to 10 years received 1 of 3 observational learning interventions-positive modeling (immunization), observational familiarity (latent inhibition), or no prevention (control)-before vicarious fear learning. Results indicated that observationally delivered manipulations inhibited vicarious fear learning, while preventions presented via written information did not. These findings confirm that vicarious learning shares some of the characteristics of direct conditioning and can explain why not all individuals will develop fear following a vicarious learning event. They also suggest that the modality of inhibitive learning is important and should match the fear learning pathway for increased chances of inhibition. Finally, the results demonstrate that positive modeling is likely to be a particularly effective method for preventing fear-related observational learning in children. (c) 2016 APA, all rights reserved).

Functions of personal and vicarious life stories: Identity and empathy

DEFF Research Database (Denmark)

Lind, Majse; Thomsen, Dorthe Kirkegaard

2018-01-01

The present study investigates functions of personal and vicarious life stories focusing on identity and empathy. Two-hundred-and-forty Danish high school students completed two life story questionnaires: One for their personal life story and one for a close other’s life story. In both...... questionnaires, they identified up to 10 chapters and self-rated the chapters on valence and valence of causal connections. In addition, they completed measures of identity disturbance and empathy. More positive personal life stories were related to lower identity disturbance and higher empathy. Vicarious life...... stories showed a similar pattern with respect to identity but surprisingly were unrelated to empathy. In addition, we found positive correlations between personal and vicarious life stories for number of chapters, chapter valence, and valence of causal connections. The study indicates that both personal...

Vicarious revenge and the death of Osama bin Laden.

Science.gov (United States)

Gollwitzer, Mario; Skitka, Linda J; Wisneski, Daniel; Sjöström, Arne; Liberman, Peter; Nazir, Syed Javed; Bushman, Brad J

2014-05-01

Three hypotheses were derived from research on vicarious revenge and tested in the context of the assassination of Osama bin Laden in 2011. In line with the notion that revenge aims at delivering a message (the "message hypothesis"), Study 1 shows that Americans' vengeful desires in the aftermath of 9/11 predicted a sense of justice achieved after bin Laden's death, and that this effect was mediated by perceptions that his assassination sent a message to the perpetrators to not "mess" with the United States. In line with the "blood lust hypothesis," his assassination also sparked a desire to take further revenge and to continue the "war on terror." Finally, in line with the "intent hypothesis," Study 2 shows that Americans (but not Pakistanis or Germans) considered the fact that bin Laden was killed intentionally more satisfactory than the possibility of bin Laden being killed accidentally (e.g., in an airplane crash).

Effects of vicarious pain on self-pain perception: investigating the role of awareness

Science.gov (United States)

Terrighena, Esslin L; Lu, Ge; Yuen, Wai Ping; Lee, Tatia MC; Keuper, Kati

2017-01-01

The observation of pain in others may enhance or reduce self-pain, yet the boundary conditions and factors that determine the direction of such effects are poorly understood. The current study set out to show that visual stimulus awareness plays a crucial role in determining whether vicarious pain primarily activates behavioral defense systems that enhance pain sensitivity and stimulate withdrawal or appetitive systems that attenuate pain sensitivity and stimulate approach. We employed a mixed factorial design with the between-subject factors exposure time (subliminal vs optimal) and vicarious pain (pain vs no pain images), and the within-subject factor session (baseline vs trial) to investigate how visual awareness of vicarious pain images affects subsequent self-pain in the cold-pressor test. Self-pain tolerance, intensity and unpleasantness were evaluated in a sample of 77 healthy participants. Results revealed significant interactions of exposure time and vicarious pain in all three dependent measures. In the presence of visual awareness (optimal condition), vicarious pain compared to no-pain elicited overall enhanced self-pain sensitivity, indexed by reduced pain tolerance and enhanced ratings of pain intensity and unpleasantness. Conversely, in the absence of visual awareness (subliminal condition), vicarious pain evoked decreased self-pain intensity and unpleasantness while pain tolerance remained unaffected. These findings suggest that the activation of defense mechanisms by vicarious pain depends on relatively elaborate cognitive processes, while – strikingly – the appetitive system is activated in highly automatic manner independent from stimulus awareness. Such mechanisms may have evolved to facilitate empathic, protective approach responses toward suffering individuals, ensuring survival of the protective social group. PMID:28831270

Vicarious learning during simulations: is it more effective than hands-on training?

Science.gov (United States)

Stegmann, Karsten; Pilz, Florian; Siebeck, Matthias; Fischer, Frank

2012-10-01

Doctor-patient communication skills are often fostered by using simulations with standardised patients (SPs). The efficiency of such experiences is greater if student observers learn at least as much from the simulation as do students who actually interact with the patient. This study aimed to investigate whether the type of simulation-based learning (learning by doing versus vicarious learning) and the order in which these activities are carried out (learning by doing → vicarious learning versus vicarious learning → learning by doing) have any effect on the acquisition of knowledge on effective doctor-patient communication strategies. In addition, we wished to examine the extent to which an observation script and a feedback formulation script affect knowledge acquisition in this domain. The sample consisted of 200 undergraduate medical students (126 female, 74 male). They participated in two separate simulation sessions, each of which was 30 minutes long and was followed by a collaborative peer feedback phase. Half of the students first performed (learning by doing) and then observed (vicarious learning) the simulation, and the other half participated in the reverse order. Knowledge of doctor-patient communication was measured before, between and after the simulations. Vicarious learning led to greater knowledge of doctor-patient communication scores than learning by doing. The order in which vicarious learning was experienced had no influence. The inclusion of an observation script also enabled significantly greater learning in students to whom this script was given compared with students who were not supported in this way, but the presence of a feedback script had no effect. Students appear to learn at least as much, if not more, about doctor-patient communication by observing their peers interact with SPs as they do from interacting with SPs themselves. Instructional support for observing simulations in the form of observation scripts facilitates both

Reductions in Children's Vicariously Learnt Avoidance and Heart Rate Responses Using Positive Modeling.

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Reynolds, Gemma; Field, Andy P; Askew, Chris

2016-03-23

Recent research has indicated that vicarious learning can lead to increases in children's fear beliefs and avoidance preferences for stimuli and that these fear responses can subsequently be reversed using positive modeling (counterconditioning). The current study investigated children's vicariously acquired avoidance behavior, physiological responses (heart rate), and attentional bias for stimuli and whether these could also be reduced via counterconditioning. Ninety-six (49 boys, 47 girls) 7- to 11-year-olds received vicarious fear learning for novel stimuli and were then randomly assigned to a counterconditioning, extinction, or control group. Fear beliefs and avoidance preferences were measured pre- and post-learning, whereas avoidance behavior, heart rate, and attentional bias were all measured post-learning. Control group children showed increases in fear beliefs and avoidance preferences for animals seen in vicarious fear learning trials. In addition, significantly greater avoidance behavior, heart rate responding, and attentional bias were observed for these animals compared to a control animal. In contrast, vicariously acquired avoidance preferences of children in the counterconditioning group were significantly reduced post-positive modeling, and these children also did not show the heightened heart rate responding to fear-paired animals. Children in the extinction group demonstrated comparable responses to the control group; thus the extinction procedure showed no effect on any fear measures. The findings suggest that counterconditioning with positive modelling can be used as an effective early intervention to reduce the behavioral and physiological effects of vicarious fear learning in childhood.

Stimulus fear relevance and the speed, magnitude, and robustness of vicariously learned fear.

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Dunne, Güler; Reynolds, Gemma; Askew, Chris

2017-08-01

Superior learning for fear-relevant stimuli is typically indicated in the laboratory by faster acquisition of fear responses, greater learned fear, and enhanced resistance to extinction. Three experiments investigated the speed, magnitude, and robustness of UK children's (6-10 years; N = 290; 122 boys, 168 girls) vicariously learned fear responses for three types of stimuli. In two experiments, children were presented with pictures of novel animals (Australian marsupials) and flowers (fear-irrelevant stimuli) alone (control) or together with faces expressing fear or happiness. To determine learning speed the number of stimulus-face pairings seen by children was varied (1, 10, or 30 trials). Robustness of learning was examined via repeated extinction procedures over 3 weeks. A third experiment compared the magnitude and robustness of vicarious fear learning for snakes and marsupials. Significant increases in fear responses were found for snakes, marsupials and flowers. There was no indication that vicarious learning for marsupials was faster than for flowers. Moreover, vicariously learned fear was neither greater nor more robust for snakes compared to marsupials, or for marsupials compared to flowers. These findings suggest that for this age group stimulus fear relevance may have little influence on vicarious fear learning. Copyright © 2017 Elsevier Ltd. All rights reserved.

A comparison of positive vicarious learning and verbal information for reducing vicariously learned fear

OpenAIRE

Reynolds, Gemma; Wasely, David; Dunne, Guler; Askew, Chris

2017-01-01

Research with children has demonstrated that both positive vicarious learning (modelling) and positive verbal information can reduce children’s acquired fear responses for a particular stimulus. However, this fear reduction appears to be more effective when the intervention pathway matches the initial fear learning pathway. That is, positive verbal information is a more effective intervention than positive modelling when fear is originally acquired via negative verbal information. Research ha...

Vicarious Fear Learning Depends on Empathic Appraisals and Trait Empathy.

Science.gov (United States)

Olsson, Andreas; McMahon, Kibby; Papenberg, Goran; Zaki, Jamil; Bolger, Niall; Ochsner, Kevin N

2016-01-01

Empathy and vicarious learning of fear are increasingly understood as separate phenomena, but the interaction between the two remains poorly understood. We investigated how social (vicarious) fear learning is affected by empathic appraisals by asking participants to either enhance or decrease their empathic responses to another individual (the demonstrator), who received electric shocks paired with a predictive conditioned stimulus. A third group of participants received no appraisal instructions and responded naturally to the demonstrator. During a later test, participants who had enhanced their empathy evinced the strongest vicarious fear learning as measured by skin conductance responses to the conditioned stimulus in the absence of the demonstrator. Moreover, this effect was augmented in observers high in trait empathy. Our results suggest that a demonstrator's expression can serve as a "social" unconditioned stimulus (US), similar to a personally experienced US in Pavlovian fear conditioning, and that learning from a social US depends on both empathic appraisals and the observers' stable traits. © The Author(s) 2015.

Vicarious Learning and Reduction of Fear in Children via Adult and Child Models.

Science.gov (United States)

Dunne, Güler; Askew, Chris

2017-06-01

Children can learn to fear stimuli vicariously, by observing adults' or peers' responses to them. Given that much of school-age children's time is typically spent with their peers, it is important to establish whether fear learning from peers is as effective or robust as learning from adults, and also whether peers can be successful positive models for reducing fear. During a vicarious fear learning procedure, children (6 to 10 years; N = 60) were shown images of novel animals together with images of adult or peer faces expressing fear. Later they saw their fear-paired animal again together with positive emotional adult or peer faces. Children's fear beliefs and avoidance for the animals increased following vicarious fear learning and decreased following positive vicarious counterconditioning. There was little evidence of differences in learning from adults and peers, demonstrating that for this age group peer models are effective models for both fear acquisition and reduction. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Vicarious Trauma: Predictors of Clinicians' Disrupted Cognitions about Self-Esteem and Self-Intimacy

Science.gov (United States)

Way, Ineke; VanDeusen, Karen; Cottrell, Tom

2007-01-01

This study examined vicarious trauma in clinicians who provide sexual abuse treatment (N = 383). A random sample of clinical members from the Association for the Treatment of Sexual Abusers and American Professional Society on the Abuse of Children were surveyed. Vicarious trauma was measured using the Trauma Stress Institute Belief Scale…

The role of vicariance vs. dispersal in shaping genetic patterns in ocellated lizard species in the western Mediterranean

DEFF Research Database (Denmark)

Paulo, O. S.; Pinheiro, J.; Miraldo, A.

2008-01-01

in the western Mediterranean as exemplified by the distribution of species and subspecies and genetic variation within the ocellated lizard group. To reassess the role of the MSC, partial sequences of three mitochondrial DNA genes (cytochrome b, 12S and 16S ribosomal RNA) and two nuclear genes (beta......-fibrinogen and C-mos) from species of the ocellated lizard group were analysed. Three alternative hypotheses were tested: that divergence was initiated (i) by post-MSC vicariance as the basin filled, (ii) when separate populations established either side of the strait by pre-MSC overseas dispersal, and (iii...

Game of Objects: vicarious causation and multi-modal media

Directory of Open Access Journals (Sweden)

Aaron Pedinotti

2013-09-01

Full Text Available This paper applies philosopher Graham Harman's object-oriented theory of "vicarious causation" to an analysis of the multi-modal media phenomenon known as "Game of Thrones." Examining the manner in which George R.R. Martin's best-selling series of fantasy novels has been adapted into a board game, a video game, and a hit HBO television series, it uses the changes entailed by these processes to trace the contours of vicariously generative relations. In the course of the resulting analysis, it provides new suggestions concerning the eidetic dimensions of Harman's causal model, particularly with regard to causation in linear networks and in differing types of game systems.

Effect of vicarious fear learning on children's heart rate responses and attentional bias for novel animals.

Science.gov (United States)

Reynolds, Gemma; Field, Andy P; Askew, Chris

2014-10-01

Research with children has shown that vicarious learning can result in changes to 2 of Lang's (1968) 3 anxiety response systems: subjective report and behavioral avoidance. The current study extended this research by exploring the effect of vicarious learning on physiological responses (Lang's final response system) and attentional bias. The study used Askew and Field's (2007) vicarious learning procedure and demonstrated fear-related increases in children's cognitive, behavioral, and physiological responses. Cognitive and behavioral changes were retested 1 week and 1 month later, and remained elevated. In addition, a visual search task demonstrated that fear-related vicarious learning creates an attentional bias for novel animals, which is moderated by increases in fear beliefs during learning. The findings demonstrate that vicarious learning leads to lasting changes in all 3 of Lang's anxiety response systems and is sufficient to create attentional bias to threat in children. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Effect of vicarious fear learning on children's heart rate responses and attentional bias for novel animals

OpenAIRE

Reynolds, G; Field, AP; Askew, C

2014-01-01

Research with children has shown that vicarious learning can result in changes to 2 of Lang's (1968) 3 anxiety response systems: subjective report and behavioral avoidance. The current study extended this research by exploring the effect of vicarious learning on physiological responses (Lang's final response system) and attentional bias. The study used Askew and Field's (2007) vicarious learning procedure and demonstrated fear-related increases in children's cognitive, behavioral, and physiol...

Effects of vicarious pain on self-pain perception: investigating the role of awareness

Directory of Open Access Journals (Sweden)

Terrighena EL

2017-07-01

Full Text Available Esslin L Terrighena,1,2 Ge Lu,1 Wai Ping Yuen,1 Tatia M C Lee,1–4 Kati Keuper1,2,5 1Department of Psychology, Laboratory of Neuropsychology, The University of Hong Kong, Hong Kong; 2Laboratory of Social Cognitive Affective Neuroscience, The University of Hong Kong, Hong Kong; 3The State Key Laboratory of Brain and Cognitive Sciences, Hong Kong; 4Institute of Clinical Neuropsychology, The University of Hong Kong, Hong Kong; 5Institute for Biomagnetism and Biosignalanalysis, University of Münster, Münster, Germany Abstract: The observation of pain in others may enhance or reduce self-pain, yet the boundary conditions and factors that determine the direction of such effects are poorly understood. The current study set out to show that visual stimulus awareness plays a crucial role in ­determining whether vicarious pain primarily activates behavioral defense systems that enhance pain sensitivity and stimulate withdrawal or appetitive systems that attenuate pain sensitivity and stimulate approach. We employed a mixed factorial design with the between-subject factors exposure time (subliminal vs optimal and vicarious pain (pain vs no pain images, and the within-subject factor session (baseline vs trial to investigate how visual awareness of vicarious pain images affects subsequent self-pain in the cold-pressor test. Self-pain tolerance, intensity and unpleasantness were evaluated in a sample of 77 healthy participants. Results revealed ­significant interactions of exposure time and vicarious pain in all three dependent measures. In the presence of visual awareness (optimal condition, vicarious pain compared to no-pain elicited overall enhanced self-pain sensitivity, indexed by reduced pain tolerance and enhanced ratings of pain intensity and unpleasantness. Conversely, in the absence of visual awareness (subliminal condition, vicarious pain evoked decreased self-pain intensity and unpleasantness while pain tolerance remained unaffected. These

Vicarious resilience and vicarious traumatisation: Experiences of working with refugees and asylum seekers in South Australia.

Science.gov (United States)

Puvimanasinghe, Teresa; Denson, Linley A; Augoustinos, Martha; Somasundaram, Daya

2015-12-01

The negative psychological impacts of working with traumatised people are well documented and include vicarious traumatisation (VT): the cumulative effect of identifying with clients' trauma stories that negatively impacts on service providers' memory, emotions, thoughts, and worldviews. More recently, the concept of vicarious resilience (VR) has been also identified: the strength, growth, and empowerment experienced by trauma workers as a consequence of their work. VR includes service providers' awareness and appreciation of their clients' capacity to grow, maintaining hope for change, as well as learning from and reassessing personal problems in the light of clients' stories of perseverance, strength, and growth. This study aimed at exploring the experiences of mental health, physical healthcare, and settlement workers caring for refugees and asylum seekers in South Australia. Using a qualitative method (data-based thematic analysis) to collect and analyse 26 semi-structured face-to-face interviews, we identified four prominent and recurring themes emanating from the data: VT, VR, work satisfaction, and cultural flexibility. These findings-among the first to describe both VT and VR in Australians working with refugee people-have important implications for policy, service quality, service providers' wellbeing, and refugee clients' lives. © The Author(s) 2015.

Effect of Vicarious Fear Learning on Children’s Heart Rate Responses and Attentional Bias for Novel Animals

Science.gov (United States)

2014-01-01

Research with children has shown that vicarious learning can result in changes to 2 of Lang’s (1968) 3 anxiety response systems: subjective report and behavioral avoidance. The current study extended this research by exploring the effect of vicarious learning on physiological responses (Lang’s final response system) and attentional bias. The study used Askew and Field’s (2007) vicarious learning procedure and demonstrated fear-related increases in children’s cognitive, behavioral, and physiological responses. Cognitive and behavioral changes were retested 1 week and 1 month later, and remained elevated. In addition, a visual search task demonstrated that fear-related vicarious learning creates an attentional bias for novel animals, which is moderated by increases in fear beliefs during learning. The findings demonstrate that vicarious learning leads to lasting changes in all 3 of Lang’s anxiety response systems and is sufficient to create attentional bias to threat in children. PMID:25151521

Examining the Effect of Small Group Discussions and Question Prompts on Vicarious Learning Outcomes

Science.gov (United States)

Lee, Yekyung; Ertmer, Peggy A.

2006-01-01

This study investigated the effect of group discussions and question prompts on students' vicarious learning experiences. Vicarious experiences were delivered to 65 preservice teachers via VisionQuest, a Web site that provided examples of successful technology integration. A 2x2 factorial research design employed group discussions and question…

Vicarious Effort-Based Decision-Making in Autism Spectrum Disorders.

Science.gov (United States)

Mosner, Maya G; Kinard, Jessica L; McWeeny, Sean; Shah, Jasmine S; Markiewitz, Nathan D; Damiano-Goodwin, Cara R; Burchinal, Margaret R; Rutherford, Helena J V; Greene, Rachel K; Treadway, Michael T; Dichter, Gabriel S

2017-10-01

This study investigated vicarious effort-based decision-making in 50 adolescents with autism spectrum disorders (ASD) compared to 32 controls using the Effort Expenditure for Rewards Task. Participants made choices to win money for themselves or for another person. When choosing for themselves, the ASD group exhibited relatively similar patterns of effort-based decision-making across reward parameters. However, when choosing for another person, the ASD group demonstrated relatively decreased sensitivity to reward magnitude, particularly in the high magnitude condition. Finally, patterns of responding in the ASD group were related to individual differences in consummatory pleasure capacity. These findings indicate atypical vicarious effort-based decision-making in ASD and more broadly add to the growing body of literature addressing social reward processing deficits in ASD.

Teaching parents about responsive feeding through a vicarious learning video: A pilot randomized controlled trial

Science.gov (United States)

The American Academy of Pediatrics and World Health Organization recommend responsive feeding (RF) to promote healthy eating behaviors in early childhood. This project developed and tested a vicarious learning video to teach parents RF practices. A RF vicarious learning video was developed using com...

Enabling the Development of Student Teacher Professional Identity through Vicarious Learning during an Educational Excursion

Science.gov (United States)

Steenekamp, Karen; van der Merwe, Martyn; Mehmedova, Aygul Salieva

2018-01-01

This paper explores the views of student teachers who were provided vicarious learning opportunities during an educational excursion, and how the learning enabled them to develop their teacher professional identity. This qualitative research study, using a social-constructivist lens highlights how vicarious learning influenced student teachers'…

Teaching Parents about Responsive Feeding through a Vicarious Learning Video: A Pilot Randomized Controlled Trial

Science.gov (United States)

Ledoux, Tracey; Robinson, Jessica; Baranowski, Tom; O'Connor, Daniel P.

2018-01-01

The American Academy of Pediatrics and World Health Organization recommend responsive feeding (RF) to promote healthy eating behaviors in early childhood. This project developed and tested a vicarious learning video to teach parents RF practices. A RF vicarious learning video was developed using community-based participatory research methods.…

Flexible goal imitation: Vicarious feedback influences stimulus-response binding by observation.

Science.gov (United States)

Giesen, Carina; Scherdin, Kerstin; Rothermund, Klaus

2017-06-01

This study investigated whether vicarious feedback influences binding processes between stimuli and observed responses. Two participants worked together in a shared color categorization task, taking the roles of actor and observer in turns. During a prime trial, participants saw a word while observing the other person executing a specific response. Automatic binding of words and observed responses into stimulus-response (S-R) episodes was assessed via word repetition effects in a subsequent probe trial in which either the same (compatible) or a different (incompatible) response had to be executed by the participants in response to the same or a different word. Results showed that vicarious prime feedback (i.e., the feedback that the other participant received for her or his response in the prime) modulated S-R retrieval effects: After positive vicarious prime feedback, typical S-R retrieval effects emerged (i.e., performance benefits for stimulus repetition probes with compatible responses, but performance costs for stimulus repetition probes with incompatible responses emerged). Notably, however, S-R-retrieval effects were reversed after vicarious negative prime feedback (meaning that stimulus repetition in the probe resulted in performance costs if prime and probe responses were compatible, and in performance benefits for incompatible responses). Findings are consistent with a flexible goal imitation account, according to which imitation is based on an interpretative and therefore feedback-sensitive reconstruction of action goals from observed movements. In concert with earlier findings, this data support the conclusion that transient S-R binding and retrieval processes are involved in social learning phenomena.

Vicarious learning through capturing taskdirected discussions

Directory of Open Access Journals (Sweden)

F. Dineen

1999-12-01

Full Text Available The research programme on vicarious learning, part of which we report in this paper, has been aimed at exploring the idea that learning can be facilitated by providing learners with access to the experiences of other learners. We use Bandura's term vicarious learning to describe this (Bandura, 1986, and we believe it to be a paradigm that offers particular promise when seen as an innovative way of exploiting recent technical advances in multimedia and distance learning technologies. It offers the prospect of a real alternative to the building of intelligent tutors (which directly address the problem of allowing learners access to dialogue, but which have proved largely intractable in practice or to the direct support of live dialogues (which do not offer a solution to the problem of providing 'live' tutors - unless they are between peer learners. In the research reported here our main objectives were to develop techniques to facilitate learners' access to, especially, dialogues and discussions which have arisen when other learners were faced with similar issues or problems in understanding the material. This required us to investigate means of indexing and retrieving appropriate dialogues and build on these to create an advanced prototype system for use in educational settings.

Stimulus fear-relevance and the vicarious learning pathway to childhood fears.

Science.gov (United States)

Askew, Chris; Dunne, Güler; Özdil, Zehra; Reynolds, Gemma; Field, Andy P

2013-10-01

Enhanced fear learning for fear-relevant stimuli has been demonstrated in procedures with adults in the laboratory. Three experiments investigated the effect of stimulus fear-relevance on vicarious fear learning in children (aged 6-11 years). Pictures of stimuli with different levels of fear-relevance (flowers, caterpillars, snakes, worms, and Australian marsupials) were presented alone or together with scared faces. In line with previous studies, children's fear beliefs and avoidance preferences increased for stimuli they had seen with scared faces. However, in contrast to evidence with adults, learning was mostly similar for all stimulus types irrespective of fear-relevance. The results support a proposal that stimulus preparedness is bypassed when children observationally learn threat-related information from adults.

In-Orbit Vicarious Calibration for Ocean Color and Aerosol Products

National Research Council Canada - National Science Library

Wang, Menghua

2005-01-01

It is well known that, to accurately retrieve the spectrum of the water-leaving radiance and derive the ocean color products from satellite sensors, a vicarious calibration procedure, which performs...

Scanning and vicarious learning from adverse events in health care

Directory of Open Access Journals (Sweden)

2001-01-01

Full Text Available Studies have shown that serious adverse clinical events occur in approximately 3%-10% of acute care hospital admissions, and one third of these adverse events result in permanent disability or death. These findings have led to calls for national medical error reporting systems and for greater organizational learning by hospitals. But do hospitals and hospital personnel pay enough attention to such risk information that they might learn from each other's failures or adverse events? This paper gives an overview of the importance of scanning and vicarious learning from adverse events. In it I propose that health care organizations' attention and information focus, organizational affinity, and absorptive capacity may each influence scanning and vicarious learning outcomes. Implications for future research are discussed.

Comparing Learning from Productive Failure and Vicarious Failure

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Kapur, Manu

2014-01-01

A total of 136 eighth-grade math students from 2 Singapore schools learned from either productive failure (PF) or vicarious failure (VF). PF students "generated" solutions to a complex problem targeting the concept of variance that they had not learned yet before receiving instruction on the targeted concept. VF students…

Vicarious Social Touch Biases Gazing at Faces and Facial Emotions.

Science.gov (United States)

Schirmer, Annett; Ng, Tabitha; Ebstein, Richard P

2018-02-01

Research has suggested that interpersonal touch promotes social processing and other-concern, and that women may respond to it more sensitively than men. In this study, we asked whether this phenomenon would extend to third-party observers who experience touch vicariously. In an eye-tracking experiment, participants (N = 64, 32 men and 32 women) viewed prime and target images with the intention of remembering them. Primes comprised line drawings of dyadic interactions with and without touch. Targets comprised two faces shown side-by-side, with one being neutral and the other being happy or sad. Analysis of prime fixations revealed that faces in touch interactions attracted longer gazing than faces in no-touch interactions. In addition, touch enhanced gazing at the area of touch in women but not men. Analysis of target fixations revealed that touch priming increased looking at both faces immediately after target onset, and subsequently, at the emotional face in the pair. Sex differences in target processing were nonsignificant. Together, the present results imply that vicarious touch biases visual attention to faces and promotes emotion sensitivity. In addition, they suggest that, compared with men, women are more aware of tactile exchanges in their environment. As such, vicarious touch appears to share important qualities with actual physical touch. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Global biogeography of scaly tree ferns (Cyatheaceae): evidence for Gondwanan vicariance and limited transoceanic dispersal.

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Korall, Petra; Pryer, Kathleen M

2014-02-01

Scaly tree ferns, Cyatheaceae, are a well-supported group of mostly tree-forming ferns found throughout the tropics, the subtropics and the south-temperate zone. Fossil evidence shows that the lineage originated in the Late Jurassic period. We reconstructed large-scale historical biogeographical patterns of Cyatheaceae and tested the hypothesis that some of the observed distribution patterns are in fact compatible, in time and space, with a vicariance scenario related to the break-up of Gondwana. Tropics, subtropics and south-temperate areas of the world. The historical biogeography of Cyatheaceae was analysed in a maximum likelihood framework using Lagrange. The 78 ingroup taxa are representative of the geographical distribution of the entire family. The phylogenies that served as a basis for the analyses were obtained by Bayesian inference analyses of mainly previously published DNA sequence data using MrBayes. Lineage divergence dates were estimated in a Bayesian Markov chain Monte Carlo framework using beast. Cyatheaceae originated in the Late Jurassic in either South America or Australasia. Following a range expansion, the ancestral distribution of the marginate-scaled clade included both these areas, whereas Sphaeropteris is reconstructed as having its origin only in Australasia. Within the marginate-scaled clade, reconstructions of early divergences are hampered by the unresolved relationships among the Alsophila , Cyathea and Gymnosphaera lineages. Nevertheless, it is clear that the occurrence of the Cyathea and Sphaeropteris lineages in South America may be related to vicariance, whereas transoceanic dispersal needs to be inferred for the range shifts seen in Alsophila and Gymnosphaera . The evolutionary history of Cyatheaceae involves both Gondwanan vicariance scenarios as well as long-distance dispersal events. The number of transoceanic dispersals reconstructed for the family is rather few when compared with other fern lineages. We suggest that a causal

Employers' Statutory Vicarious Liability in Terms of the Protection of Personal Information Act

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Daleen Millard

2016-07-01

Full Text Available A person whose privacy has been infringed upon through the unlawful, culpable processing of his or her personal information can sue the infringer's employer based on vicarious liability or institute action based on the Protection of Personal Information Act 4 of 2013 (POPI. Section 99(1 of POPI provides a person (a "data subject" whose privacy has been infringed upon with the right to institute a civil action against the responsible party. POPI defines the responsible party as the person who determines the purpose of and means for the processing of the personal information of data subjects. Although POPI does not equate a responsible party to an employer, the term "responsible party" is undoubtedly a synonym for "employer" in this context. By holding an employer accountable for its employees' unlawful processing of a data subject's personal information, POPI creates a form of statutory vicarious liability. Since the defences available to an employer at common law and developed by case law differ from the statutory defences available to an employer in terms of POPI, it is necessary to compare the impact this new statute has on employers. From a risk perspective, employers must be aware of the serious implications of POPI. The question that arises is whether the Act perhaps takes matters too far. This article takes a critical look at the statutory defences available to an employer in vindication of a vicarious liability action brought by a data subject in terms of section 99(1 of POPI. It compares the defences found in section 99(2 of POPI and the common-law defences available to an employer fending off a delictual claim founded on the doctrine of vicarious liability. To support the argument that the statutory vicarious liability created by POPI is too harsh, the defences contained in section 99(2 of POPI are further analogised with those available to an employer in terms of section 60(4 of the Employment Equity Act 55 of 1998 (EEA and other

Vicarious Effort-Based Decision-Making in Autism Spectrum Disorders

Science.gov (United States)

Mosner, Maya G.; Kinard, Jessica L.; McWeeny, Sean; Shah, Jasmine S.; Markiewitz, Nathan D.; Damiano-Goodwin, Cara R.; Burchinal, Margaret R.; Rutherford, Helena J. V.; Greene, Rachel K.; Treadway, Michael T.; Dichter, Gabriel S.

2017-01-01

This study investigated vicarious effort-based decision-making in 50 adolescents with autism spectrum disorders (ASD) compared to 32 controls using the Effort Expenditure for Rewards Task. Participants made choices to win money for themselves or for another person. When choosing for themselves, the ASD group exhibited relatively similar patterns…

Effects of Vicarious Experiences of Nature, Environmental Attitudes, and Outdoor Recreation Benefits on Support for Increased Funding Allocations

Science.gov (United States)

Kil, Namyun

2016-01-01

This study examined the effects of vicarious experiences of nature, environmental attitudes, and recreation benefits sought by participants on their support for funding of natural resources and alternative energy options. Using a national scenic trail user survey, results demonstrated that vicarious experiences of nature influenced environmental…

The Deep-Level-Reasoning-Question Effect: The Role of Dialogue and Deep-Level-Reasoning Questions during Vicarious Learning

Science.gov (United States)

Craig, Scotty D.; Sullins, Jeremiah; Witherspoon, Amy; Gholson, Barry

2006-01-01

We investigated the impact of dialogue and deep-level-reasoning questions on vicarious learning in 2 studies with undergraduates. In Experiment 1, participants learned material by interacting with AutoTutor or by viewing 1 of 4 vicarious learning conditions: a noninteractive recorded version of the AutoTutor dialogues, a dialogue with a…

Vicarious Learning from Human Models in Monkeys

OpenAIRE

Falcone, Rossella; Brunamonti, Emiliano; Genovesio, Aldo

2012-01-01

We examined whether monkeys can learn by observing a human model, through vicarious learning. Two monkeys observed a human model demonstrating an object-reward association and consuming food found underneath an object. The monkeys observed human models as they solved more than 30 learning problems. For each problem, the human models made a choice between two objects, one of which concealed a piece of apple. In the test phase afterwards, the monkeys made a choice of their own. Learning was app...

FACTORS INFLUENCING VICARIOUS LEARNING MECHANISM EFFECTIVENESS WITHIN ORGANIZATIONS

OpenAIRE

JOHN R. VOIT; COLIN G. DRURY

2013-01-01

As organizations become larger it becomes increasingly difficult to share lessons-learned across their disconnected units allowing individuals to learn vicariously from each other's experiences. This lesson-learned information is often unsolicited by the recipient group or individual and required an individual or group to react to the information to yield benefits for the organization. Data was collected using 39 interviews and 582 survey responses that proved the effects of information usefu...

Vicarious learning and unlearning of fear in childhood via mother and stranger models.

Science.gov (United States)

Dunne, Güler; Askew, Chris

2013-10-01

Evidence shows that anxiety runs in families. One reason may be that children are particularly susceptible to learning fear from their parents. The current study compared children's fear beliefs and avoidance preferences for animals following positive or fearful modeling by mothers and strangers in vicarious learning and unlearning procedures. Children aged 6 to 10 years (N = 60) were exposed to pictures of novel animals either alone (control) or together with pictures of their mother or a stranger expressing fear or happiness. During unlearning (counterconditioning), children saw each animal again with their mother or a stranger expressing the opposite facial expression. Following vicarious learning, children's fear beliefs increased for animals seen with scared faces and this effect was the same whether fear was modeled by mothers or strangers. Fear beliefs and avoidance preferences decreased following positive counterconditioning and increased following fear counterconditioning. Again, learning was the same whether the model was the child's mother or a stranger. These findings indicate that children in this age group can vicariously learn and unlearn fear-related cognitions from both strangers and mothers. This has implications for our understanding of fear acquisition and the development of early interventions to prevent and reverse childhood fears and phobias.

Both Direct and Vicarious Experiences of Nature Affect Children's Willingness to Conserve Biodiversity.

Science.gov (United States)

Soga, Masashi; Gaston, Kevin J; Yamaura, Yuichi; Kurisu, Kiyo; Hanaki, Keisuke

2016-05-25

Children are becoming less likely to have direct contact with nature. This ongoing loss of human interactions with nature, the extinction of experience, is viewed as one of the most fundamental obstacles to addressing global environmental challenges. However, the consequences for biodiversity conservation have been examined very little. Here, we conducted a questionnaire survey of elementary schoolchildren and investigated effects of the frequency of direct (participating in nature-based activities) and vicarious experiences of nature (reading books or watching TV programs about nature and talking about nature with parents or friends) on their affective attitudes (individuals' emotional feelings) toward and willingness to conserve biodiversity. A total of 397 children participated in the surveys in Tokyo. Children's affective attitudes and willingness to conserve biodiversity were positively associated with the frequency of both direct and vicarious experiences of nature. Path analysis showed that effects of direct and vicarious experiences on children's willingness to conserve biodiversity were mediated by their affective attitudes. This study demonstrates that children who frequently experience nature are likely to develop greater emotional affinity to and support for protecting biodiversity. We suggest that children should be encouraged to experience nature and be provided with various types of these experiences.

Vicarious audiovisual learning in perfusion education.

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Rath, Thomas E; Holt, David W

2010-12-01

Perfusion technology is a mechanical and visual science traditionally taught with didactic instruction combined with clinical experience. It is difficult to provide perfusion students the opportunity to experience difficult clinical situations, set up complex perfusion equipment, or observe corrective measures taken during catastrophic events because of patient safety concerns. Although high fidelity simulators offer exciting opportunities for future perfusion training, we explore the use of a less costly low fidelity form of simulation instruction, vicarious audiovisual learning. Two low fidelity modes of instruction; description with text and a vicarious, first person audiovisual production depicting the same content were compared. Students (n = 37) sampled from five North American perfusion schools were prospectively randomized to one of two online learning modules, text or video.These modules described the setup and operation of the MAQUET ROTAFLOW stand-alone centrifugal console and pump. Using a 10 question multiple-choice test, students were assessed immediately after viewing the module (test #1) and then again 2 weeks later (test #2) to determine cognition and recall of the module content. In addition, students completed a questionnaire assessing the learning preferences of today's perfusion student. Mean test scores from test #1 for video learners (n = 18) were significantly higher (88.89%) than for text learners (n = 19) (74.74%), (p audiovisual learning modules may be an efficacious, low cost means of delivering perfusion training on subjects such as equipment setup and operation. Video learning appears to improve cognition and retention of learned content and may play an important role in how we teach perfusion in the future, as simulation technology becomes more prevalent.

Promoting Vicarious Learning of Physics Using Deep Questions with Explanations

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Craig, Scotty D.; Gholson, Barry; Brittingham, Joshua K.; Williams, Joah L.; Shubeck, Keith T.

2012-01-01

Two experiments explored the role of vicarious "self" explanations in facilitating student learning gains during computer-presented instruction. In Exp. 1, college students with low or high knowledge on Newton's laws were tested in four conditions: (a) monologue (M), (b) questions (Q), (c) explanation (E), and (d) question + explanation (Q + E).…

Influencing Republicans' and Democrats' attitudes toward Obamacare: Effects of imagined vicarious cognitive dissonance on political attitudes.

Science.gov (United States)

Cooper, Joel; Feldman, Lauren A; Blackman, Shane F

2018-04-16

The field of experimental social psychology is appropriately interested in using novel theoretical approaches to implement change in the social world. In the current study, we extended cognitive dissonance theory by creating a new framework of social influence: imagined vicarious dissonance. We used the framework to influence attitudes on an important and controversial political attitude: U.S. citizens' support for the Affordable Care Act (ACA). 36 Republicans and 84 Democrats were asked to imagine fellow Republicans and Democrats, respectively, making attitude discrepant statements under high and low choice conditions about support for the ACA. The data showed that vicarious dissonance, established by imagining a group member make a counterattitudinal speech under high-choice conditions (as compared to low-choice conditions), resulted in greater support for the Act by Republicans and marginally diminished support by Democrats. The results suggest a promising role for the application of vicarious dissonance theory to relevant societal issues and for further understanding the relationship of dissonance and people's identification with their social groups.

The shifting roles of dispersal and vicariance in biogeography.

OpenAIRE

Zink, R M; Blackwell-Rago, R C; Ronquist, F

2000-01-01

Dispersal and vicariance are often contrasted as competing processes primarily responsible for spatial and temporal patterns of biotic diversity. Recent methods of biogeographical reconstruction recognize the potential of both processes, and the emerging question is about discovering their relative frequencies. Relatively few empirical studies, especially those employing molecular phylogenies that allow a temporal perspective, have attempted to estimate the relative roles of dispersal and vic...

Hydroxylation of nitro-(pentafluorosulfanyl)benzenes via vicarious nucleophilic substitution of hydrogen

Czech Academy of Sciences Publication Activity Database

Beier, Petr; Pastýříková, Tereza

2011-01-01

Roč. 52, č. 34 (2011), s. 4392-4394 ISSN 0040-4039 R&D Projects: GA ČR GAP207/11/0344 Institutional research plan: CEZ:AV0Z40550506 Keywords : pentafluorosulfanyl group * vicarious nucleophilic substitution * hydroxylation Subject RIV: CC - Organic Chemistry Impact factor: 2.683, year: 2011

Coping with Vicarious Trauma in the Aftermath of a Natural Disaster

Science.gov (United States)

Smith, Lauren E.; Bernal, Darren R.; Schwartz, Billie S.; Whitt, Courtney L.; Christman, Seth T.; Donnelly, Stephanie; Wheatley, Anna; Guillaume, Casta; Nicolas, Guerda; Kish, Jonathan; Kobetz, Erin

2014-01-01

This study documents the vicarious psychological impact of the 2010 earthquake in Haiti on Haitians living in the United States. The role of coping resources--family, religious, and community support--was explored. The results highlight the importance of family and community as coping strategies to manage such trauma.

Vicarious Desensitization of Test Anxiety Through Observation of Video-taped Treatment

Science.gov (United States)

Mann, Jay

1972-01-01

Procedural variations were compared for a vicarious group treatment of test anxiety involving observation of videotapes depicting systematic desensitization of a model. The theoretical implications of the present study and the feasibility of using videotaped materials to treat test anxiety and other avoidance responses in school settings are…

Both Direct and Vicarious Experiences of Nature Affect Children’s Willingness to Conserve Biodiversity

Directory of Open Access Journals (Sweden)

Masashi Soga

2016-05-01

Full Text Available Children are becoming less likely to have direct contact with nature. This ongoing loss of human interactions with nature, the extinction of experience, is viewed as one of the most fundamental obstacles to addressing global environmental challenges. However, the consequences for biodiversity conservation have been examined very little. Here, we conducted a questionnaire survey of elementary schoolchildren and investigated effects of the frequency of direct (participating in nature-based activities and vicarious experiences of nature (reading books or watching TV programs about nature and talking about nature with parents or friends on their affective attitudes (individuals’ emotional feelings toward and willingness to conserve biodiversity. A total of 397 children participated in the surveys in Tokyo. Children’s affective attitudes and willingness to conserve biodiversity were positively associated with the frequency of both direct and vicarious experiences of nature. Path analysis showed that effects of direct and vicarious experiences on children’s willingness to conserve biodiversity were mediated by their affective attitudes. This study demonstrates that children who frequently experience nature are likely to develop greater emotional affinity to and support for protecting biodiversity. We suggest that children should be encouraged to experience nature and be provided with various types of these experiences.

Social work in oncology-managing vicarious trauma-the positive impact of professional supervision.

Science.gov (United States)

Joubert, Lynette; Hocking, Alison; Hampson, Ralph

2013-01-01

This exploratory study focused on the experience and management of vicarious trauma in a team of social workers (N = 16) at a specialist cancer hospital in Melbourne. Respondents completed the Traumatic Stress Institute Belief Scale (TSIBS), the Professional Quality of Life Scale (ProQOL), and participated in four focus groups. The results from the TSIBS and the ProQol scales confirm that there is a stress associated with the social work role within a cancer service, as demonstrated by the high scores related to stress. However at the same time the results indicated a high level of satisfaction which acted as a mitigating factor. The study also highlighted the importance of supervision and management support. A model for clinical social work supervision is proposed to reduce the risks associated with vicarious trauma.

Vicariance or long-distance dispersal: historical biogeography of the pantropical subfamily Chrysophylloideae (Sapotaceae)

Czech Academy of Sciences Publication Activity Database

Bartish, Igor; Antonelli, A.; Richardson, J. E.; Swenson, U.

2011-01-01

Roč. 38, č. 1 (2011), s. 177-190 ISSN 0305-0270 Institutional research plan: CEZ:AV0Z60050516 Keywords : molecular dating * Neotropics * vicariance Subject RIV: EF - Botanics Impact factor: 4.544, year: 2011

Vicarious reinforcement learning signals when instructing others.

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Apps, Matthew A J; Lesage, Elise; Ramnani, Narender

2015-02-18

Reinforcement learning (RL) theory posits that learning is driven by discrepancies between the predicted and actual outcomes of actions (prediction errors [PEs]). In social environments, learning is often guided by similar RL mechanisms. For example, teachers monitor the actions of students and provide feedback to them. This feedback evokes PEs in students that guide their learning. We report the first study that investigates the neural mechanisms that underpin RL signals in the brain of a teacher. Neurons in the anterior cingulate cortex (ACC) signal PEs when learning from the outcomes of one's own actions but also signal information when outcomes are received by others. Does a teacher's ACC signal PEs when monitoring a student's learning? Using fMRI, we studied brain activity in human subjects (teachers) as they taught a confederate (student) action-outcome associations by providing positive or negative feedback. We examined activity time-locked to the students' responses, when teachers infer student predictions and know actual outcomes. We fitted a RL-based computational model to the behavior of the student to characterize their learning, and examined whether a teacher's ACC signals when a student's predictions are wrong. In line with our hypothesis, activity in the teacher's ACC covaried with the PE values in the model. Additionally, activity in the teacher's insula and ventromedial prefrontal cortex covaried with the predicted value according to the student. Our findings highlight that the ACC signals PEs vicariously for others' erroneous predictions, when monitoring and instructing their learning. These results suggest that RL mechanisms, processed vicariously, may underpin and facilitate teaching behaviors. Copyright © 2015 Apps et al.

Vicarious liability and criminal prosecutions for regulatory offences.

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Freckelton, Ian

2006-08-01

The parameters of vicarious liability of corporations for the conduct of their employees, especially in the context of provisions that criminalise breaches of regulatory provisions, are complex. The decision of Bell J in ABC Developmental Learning Centres Pty Ltd v Wallace [2006] VSC 171 raises starkly the potential unfairness of an approach which converts criminal liability of corporations too readily into absolute liability, irrespective of the absence of any form of proven culpability. The author queries whether fault should not be brought back in some form to constitute a determinant of criminal liability for corporations.

Vicariously learned helplessness: the role of perceived dominance and prestige of a model.

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Chambers, Sheridan; Hammonds, Frank

2014-01-01

Prior research has examined the relationship between various model characteristics (e.g., age, competence, similarity) and the likelihood that the observers will experience vicariously learned helplessness. However, no research in this area has investigated dominance as a relevant model characteristic. This study explored whether the vicarious acquisition of learned helplessness could be mediated by the perceived dominance of a model. Participants observed a model attempting to solve anagrams. Across participant groups, the model displayed either dominant or nondominant characteristics and was either successful or unsuccessful at solving the anagrams. The characteristics displayed by the model significantly affected observers' ratings of his dominance and prestige. After viewing the model, participants attempted to solve 40 anagrams. When the dominant model was successful, observers solved significantly more anagrams than when he was unsuccessful. This effect was not found when the model was nondominant.

Hippocampus, delay discounting, and vicarious trial-and-error.

Science.gov (United States)

Bett, David; Murdoch, Lauren H; Wood, Emma R; Dudchenko, Paul A

2015-05-01

In decision-making, an immediate reward is usually preferred to a delayed reward, even if the latter is larger. We tested whether the hippocampus is necessary for this form of temporal discounting, and for vicarious trial-and-error at the decision point. Rats were trained on a recently developed, adjustable delay-discounting task (Papale et al. (2012) Cogn Affect Behav Neurosci 12:513-526), which featured a choice between a small, nearly immediate reward, and a larger, delayed reward. Rats then received either hippocampus or sham lesions. Animals with hippocampus lesions adjusted the delay for the larger reward to a level similar to that of sham-lesioned animals, suggesting a similar valuation capacity. However, the hippocampus lesion group spent significantly longer investigating the small and large rewards in the first part of the sessions, and were less sensitive to changes in the amount of reward in the large reward maze arm. Both sham- and hippocampus-lesioned rats showed a greater amount of vicarious trial-and-error on trials in which the delay was adjusted. In a nonadjusting version of the delay discounting task, animals with hippocampus lesions showed more variability in their preference for a larger reward that was delayed by 10 s compared with sham-lesioned animals. To verify the lesion behaviorally, rat were subsequently trained on a water maze task, and rats with hippocampus lesions were significantly impaired compared with sham-lesioned animals. The findings on the delay discounting tasks suggest that damage to the hippocampus may impair the detection of reward magnitude. © 2014 Wiley Periodicals, Inc.

Attitude change as a function of the observation of vicarious reinforcement and friendliness

OpenAIRE

Stocker-Kreichgauer, Gisela

1982-01-01

Attitude change as a function of the observation of vicarious reinforcement and friendliness : hostility in a debate / Lutz von Rosenstiel ; Gisela Stocker- Kreichgauer. - In: Group decision making / ed. by Gisela Stocker-Kreichgauer ... - London u.a. : Acad. Press, 1982. - S. 241-255. - (European monographs in social psychology ; 25)

No experience required: Violent crime and anticipated, vicarious, and experienced racial discrimination.

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Herda, Daniel; McCarthy, Bill

2018-02-01

There is a growing body of evidence linking racial discrimination and juvenile crime, and a number of theories explain this relationship. In this study, we draw on one popular approach, Agnew's general strain theory, and extend prior research by moving from a focus on experienced discrimination to consider two other forms, anticipated and vicarious discrimination. Using data on black, white, and Hispanic youth, from the Project on Human Development in Chicago Neighborhoods (PHDCN), we find that experienced, anticipated, and to a lesser extent, vicarious discrimination, significantly predict violent crime independent of a set of neighborhood, parental, and individual level controls, including prior violent offending. Additional analyses on the specific contexts of discrimination reveal that violence is associated with the anticipation of police discrimination. The effects tend to be larger for African American than Hispanic youth, but the differences are not statistically significant. These findings support the thesis that, like other strains, discrimination may not have to be experienced directly to influence offending. Copyright © 2017. Published by Elsevier Inc.

Microscale vicariance and diversification of Western Balkan caddisflies linked to karstification.

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Previšić, Ana; Schnitzler, Jan; Kučinić, Mladen; Graf, Wolfram; Ibrahimi, Halil; Kerovec, Mladen; Pauls, Steffen U

2014-03-01

The karst areas in the Dinaric region of the Western Balkan Peninsula are a hotspot of freshwater biodiversity. Many investigators have examined diversification of the subterranean freshwater fauna in these karst systems. However, diversification of surface-water fauna remains largely unexplored. We assessed local and regional diversification of surface-water species in karst systems and asked whether patterns of population differentiation could be explained by dispersal-diversification processes or allopatric diversification following karst-related microscale vicariance. We analyzed mitochondrial cytochrome c oxidase subunit I (mtCOI) sequence data of 4 caddisfly species (genus Drusus ) in a phylogeographic framework to assess local and regional population genetic structure and Pliocene/Pleistocene history. We used BEAST software to assess the timing of intraspecific diversification of the target species. We compared climate envelopes of the study species and projected climatically suitable areas during the last glacial maximum (LGM) to assess differences in the species climatic niches and infer potential LGM refugia. The haplotype distribution of the 4 species (324 individuals from 32 populations) was characterized by strong genetic differentiation with few haplotypes shared among populations (16%) and deep divergence among populations of the 3 endemic species, even at local scales. Divergence among local populations of endemics often exceeded divergence among regional and continental clades of the widespread D. discolor . Major divergences among regional populations dated to 2.0 to 0.5 Mya. Species distribution model projections and genetic structure suggest that the endemic species persisted in situ and diversified locally throughout multiple Pleistocene climate cycles. The pattern for D. discolor was different and consistent with multiple invasions into the region. Patterns of population genetic structure and diversification were similar for the 3 regional

Vicariously touching products through observing others' hand actions increases purchasing intention, and the effect of visual perspective in this process: An fMRI study.

Science.gov (United States)

Liu, Yi; Zang, Xuelian; Chen, Lihan; Assumpção, Leonardo; Li, Hong

2018-01-01

The growth of online shopping increases consumers' dependence on vicarious sensory experiences, such as observing others touching products in commercials. However, empirical evidence on whether observing others' sensory experiences increases purchasing intention is still scarce. In the present study, participants observed others interacting with products in the first- or third-person perspective in video clips, and their neural responses were measured with functional magnetic resonance imaging (fMRI). We investigated (1) whether and how vicariously touching certain products affected purchasing intention, and the neural correlates of this process; and (2) how visual perspective interacts with vicarious tactility. Vicarious tactile experiences were manipulated by hand actions touching or not touching the products, while the visual perspective was manipulated by showing the hand actions either in first- or third-person perspective. During the fMRI scanning, participants watched the video clips and rated their purchasing intention for each product. The results showed that, observing others touching (vs. not touching) the products increased purchasing intention, with vicarious neural responses found in mirror neuron systems (MNS) and lateral occipital complex (LOC). Moreover, the stronger neural activities in MNS was associated with higher purchasing intention. The effects of visual perspectives were found in left superior parietal lobule (SPL), while the interaction of tactility and visual perspective was shown in precuneus and precuneus-LOC connectivity. The present study provides the first evidence that vicariously touching a given product increased purchasing intention and the neural activities in bilateral MNS, LOC, left SPL and precuneus are involved in this process. Hum Brain Mapp 39:332-343, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Vicarious Racism: A Qualitative Analysis of Experiences with Secondhand Racism in Graduate Education

Science.gov (United States)

Truong, Kimberly A.; Museus, Samuel D.; McGuire, Keon M.

2016-01-01

In this article, the authors examine the role of vicarious racism in the experiences of doctoral students of color. The researchers conducted semi-structured individual interviews with 26 doctoral students who self-reported experiencing racism and racial trauma during their doctoral studies. The analysis generated four themes that detail the…

The Impact of Enactive /Vicarious pre-reading Tasks on Reading Comprehension and Self-Efficacy of Iranian Pre-Intermediate EFL Learners

Directory of Open Access Journals (Sweden)

Arezoo Eshghipour

2016-01-01

Full Text Available This study investigated the effect of enactive pre-reading tasks on Iranian pre-intermediate EFL learners’ reading comprehension and self-efficacy. Moreover, it explored whether Iranian per-intermediate EFL learners’ reading comprehension and self-efficacy are influenced by vicarious pre-reading tasks. The required data was gathered through a reading comprehension passage entailing 20 comprehension questions and a 30-item self-efficacy questionnaire with 5-point Likert-scale response options. A total of 66 participants (including 34 individuals in the enactive group and 32 leaners in the vicarious one took part in this study. The Pearson formula, an independent T-Test, paired T-test, and the Mann-Whitney U test were used to analyze the data. Based on the findings of the study, enactive pre-reading tasks played a key role in the Iranian pre-intermediate EFL learners’ reading comprehension ability. Moreover, it was found that vicarious pre-reading tasks served an important role in the Iranian pre-intermediate EFL learners’ self-efficacy.

Vicarious absolute radiometric calibration of GF-2 PMS2 sensor using permanent artificial targets in China

Science.gov (United States)

Liu, Yaokai; Li, Chuanrong; Ma, Lingling; Wang, Ning; Qian, Yonggang; Tang, Lingli

2016-10-01

GF-2, launched on August 19 2014, is one of the high-resolution land resource observing satellite of the China GF series satellites plan. The radiometric performance evaluation of the onboard optical pan and multispectral (PMS2) sensor of GF-2 satellite is very important for the further application of the data. And, the vicarious absolute radiometric calibration approach is one of the most useful way to monitor the radiometric performance of the onboard optical sensors. In this study, the traditional reflectance-based method is used to vicarious radiometrically calibrate the onboard PMS2 sensor of GF-2 satellite using three black, gray and white reflected permanent artificial targets located in the AOE Baotou site in China. Vicarious field calibration campaign were carried out in the AOE-Baotou calibration site on 22 April 2016. And, the absolute radiometric calibration coefficients were determined with in situ measured atmospheric parameters and surface reflectance of the permanent artificial calibration targets. The predicted TOA radiance of a selected desert area with our determined calibrated coefficients were compared with the official distributed calibration coefficients. Comparison results show a good consistent and the mean relative difference of the multispectral channels is less than 5%. Uncertainty analysis was also carried out and a total uncertainty with 3.87% is determined of the TOA radiance.

Vicarious Traumatisation in Practitioners Who Work with Adult Survivors of Sexual Violence in Child Sexual Abuse: Literature Review and Directions for Future Research

OpenAIRE

Choularia, Zoe; Hutchison, Craig; Karatzias, Thanos

2009-01-01

Primary objective: The authors sought to summarise and evaluate evidence regarding vicarious traumatisation (VT) in practitioners working with adult survivors of sexual violence and/or child sexual abuse (CSA). Methods and selection criteria: Relevant publications were identified from systematic literature searches of PubMed and PsycINFO. Studies were selected for inclusion if they examined vicarious traumatisation resulting from sexual violence and/or CSA work and were published in English b...

Development of vicarious trial-and-error behavior in odor discrimination learning in the rat: relation to hippocampal function?

Science.gov (United States)

Hu, D; Griesbach, G; Amsel, A

1997-06-01

Previous work from our laboratory has suggested that hippocampal electrolytic lesions result in a deficit in simultaneous, black-white discrimination learning and reduce the frequency of vicarious trial-and-error (VTE) at a choice-point. VTE is a term Tolman used to describe the rat's conflict-like behavior, moving its head from one stimulus to the other at a choice point, and has been proposed as a major nonspatial feature of hippocampal function in both visual and olfactory discrimination learning. Simultaneous odor discrimination and VTE behavior were examined at three different ages. The results were that 16-day-old pups made fewer VTEs and learned much more slowly than 30- and 60-day-olds, a finding in accord with levels of hippocampal maturity in the rat.

Effects over time of self-reported direct and vicarious racial discrimination on depressive symptoms and loneliness among Australian school students.

Science.gov (United States)

Priest, Naomi; Perry, Ryan; Ferdinand, Angeline; Kelaher, Margaret; Paradies, Yin

2017-02-03

Racism and racial discrimination are increasingly acknowledged as a critical determinant of health and health inequalities. However, patterns and impacts of racial discrimination among children and adolescents remain under-investigated, including how different experiences of racial discrimination co-occur and influence health and development over time. This study examines associations between self-reported direct and vicarious racial discrimination experiences and loneliness and depressive symptoms over time among Australian school students. Across seven schools, 142 students (54.2% female), age at T1 from 8 to 15 years old (M = 11.14, SD = 2.2), and from diverse racial/ethnic and migration backgrounds (37.3% born in English-speaking countries as were one or both parents) self-reported racial discrimination experiences (direct and vicarious) and mental health (depressive symptoms and loneliness) at baseline and 9 months later at follow up. A full cross-lagged panel design was modelled using MPLUS v.7 with all variables included at both time points. A cross-lagged effect of perceived direct racial discrimination on later depressive symptoms and on later loneliness was found. As expected, the effect of direct discrimination on both health outcomes was unidirectional as mental health did not reciprocally influence reported racism. There was no evidence that vicarious racial discrimination influenced either depressive symptoms or loneliness beyond the effect of direct racial discrimination. Findings suggest direct racial discrimination has a persistent effect on depressive symptoms and loneliness among school students over time. Future work to explore associations between direct and vicarious discrimination is required.

Social identity shapes social valuation: evidence from prosocial behavior and vicarious reward.

Science.gov (United States)

Hackel, Leor M; Zaki, Jamil; Van Bavel, Jay J

2017-08-01

People frequently engage in more prosocial behavior toward members of their own groups, as compared to other groups. Such group-based prosociality may reflect either strategic considerations concerning one's own future outcomes or intrinsic value placed on the outcomes of in-group members. In a functional magnetic resonance imaging experiment, we examined vicarious reward responses to witnessing the monetary gains of in-group and out-group members, as well as prosocial behavior towards both types of individuals. We found that individuals' investment in their group-a motivational component of social identification-tracked the intensity of their responses in ventral striatum to in-group (vs out-group) members' rewards, as well as their tendency towards group-based prosociality. Individuals with strong motivational investment in their group preferred rewards for an in-group member, whereas individuals with low investment preferred rewards for an out-group member. These findings suggest that the motivational importance of social identity-beyond mere similarity to group members-influences vicarious reward and prosocial behavior. More broadly, these findings support a theoretical framework in which salient social identities can influence neural representations of subjective value, and suggest that social preferences can best be understood by examining the identity contexts in which they unfold. © The Author (2017). Published by Oxford University Press.

Predictive hypotheses are ineffectual in resolving complex biochemical systems.

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Fry, Michael

2018-03-20

Scientific hypotheses may either predict particular unknown facts or accommodate previously-known data. Although affirmed predictions are intuitively more rewarding than accommodations of established facts, opinions divide whether predictive hypotheses are also epistemically superior to accommodation hypotheses. This paper examines the contribution of predictive hypotheses to discoveries of several bio-molecular systems. Having all the necessary elements of the system known beforehand, an abstract predictive hypothesis of semiconservative mode of DNA replication was successfully affirmed. However, in defining the genetic code whose biochemical basis was unclear, hypotheses were only partially effective and supplementary experimentation was required for its conclusive definition. Markedly, hypotheses were entirely inept in predicting workings of complex systems that included unknown elements. Thus, hypotheses did not predict the existence and function of mRNA, the multiple unidentified components of the protein biosynthesis machinery, or the manifold unknown constituents of the ubiquitin-proteasome system of protein breakdown. Consequently, because of their inability to envision unknown entities, predictive hypotheses did not contribute to the elucidation of cation theories remained the sole instrument to explain complex bio-molecular systems, the philosophical question of alleged advantage of predictive over accommodative hypotheses became inconsequential.

The Phylogeny and Biogeographic History of Ashes (Fraxinus, Oleaceae) Highlight the Roles of Migration and Vicariance in the Diversification of Temperate Trees

Science.gov (United States)

Hinsinger, Damien Daniel; Basak, Jolly; Gaudeul, Myriam; Cruaud, Corinne; Bertolino, Paola; Frascaria-Lacoste, Nathalie; Bousquet, Jean

2013-01-01

The cosmopolitan genus Fraxinus, which comprises about 40 species of temperate trees and shrubs occupying various habitats in the Northern Hemisphere, represents a useful model to study speciation in long-lived angiosperms. We used nuclear external transcribed spacers (nETS), phantastica gene sequences, and two chloroplast loci (trnH-psbA and rpl32-trnL) in combination with previously published and newly obtained nITS sequences to produce a time-calibrated multi-locus phylogeny of the genus. We then inferred the biogeographic history and evolution of floral morphology. An early dispersal event could be inferred from North America to Asia during the Oligocene, leading to the diversification of the section Melioides sensus lato. Another intercontinental dispersal originating from the Eurasian section of Fraxinus could be dated from the Miocene and resulted in the speciation of F. nigra in North America. In addition, vicariance was inferred to account for the distribution of the other Old World species (sections Sciadanthus, Fraxinus and Ornus). Geographic speciation likely involving dispersal and vicariance could also be inferred from the phylogenetic grouping of geographically close taxa. Molecular dating suggested that the initial divergence of the taxonomical sections occurred during the middle and late Eocene and Oligocene periods, whereas diversification within sections occurred mostly during the late Oligocene and Miocene, which is consistent with the climate warming and accompanying large distributional changes observed during these periods. These various results underline the importance of dispersal and vicariance in promoting geographic speciation and diversification in Fraxinus. Similarities in life history, reproductive and demographic attributes as well as geographical distribution patterns suggest that many other temperate trees should exhibit similar speciation patterns. On the other hand, the observed parallel evolution and reversions in floral

Just watching the game ain't enough: striatal fMRI reward responses to successes and failures in a video game during active and vicarious playing.

Science.gov (United States)

Kätsyri, Jari; Hari, Riitta; Ravaja, Niklas; Nummenmaa, Lauri

2013-01-01

Although the multimodal stimulation provided by modern audiovisual video games is pleasing by itself, the rewarding nature of video game playing depends critically also on the players' active engagement in the gameplay. The extent to which active engagement influences dopaminergic brain reward circuit responses remains unsettled. Here we show that striatal reward circuit responses elicited by successes (wins) and failures (losses) in a video game are stronger during active than vicarious gameplay. Eleven healthy males both played a competitive first-person tank shooter game (active playing) and watched a pre-recorded gameplay video (vicarious playing) while their hemodynamic brain activation was measured with 3-tesla functional magnetic resonance imaging (fMRI). Wins and losses were paired with symmetrical monetary rewards and punishments during active and vicarious playing so that the external reward context remained identical during both conditions. Brain activation was stronger in the orbitomedial prefrontal cortex (omPFC) during winning than losing, both during active and vicarious playing. In contrast, both wins and losses suppressed activations in the midbrain and striatum during active playing; however, the striatal suppression, particularly in the anterior putamen, was more pronounced during loss than win events. Sensorimotor confounds related to joystick movements did not account for the results. Self-ratings indicated losing to be more unpleasant during active than vicarious playing. Our findings demonstrate striatum to be selectively sensitive to self-acquired rewards, in contrast to frontal components of the reward circuit that process both self-acquired and passively received rewards. We propose that the striatal responses to repeated acquisition of rewards that are contingent on game related successes contribute to the motivational pull of video-game playing.

Just watching the game ain’t enough: Striatal fMRI reward responses to successes and failures in a video game during active and vicarious playing

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Jari eKätsyri

2013-06-01

Full Text Available Although the multimodal stimulation provided by modern audiovisual video games is pleasing by itself, the rewarding nature of video game playing depends critically also on the players’ active engagement in the gameplay. The extent to which active engagement influences dopaminergic brain reward circuit responses remains unsettled. Here we show that striatal reward circuit responses elicited by successes (wins and failures (losses in a video game are stronger during active than vicarious gameplay. Eleven healthy males both played a competitive first-person tank shooter game (active playing and watched a pre-recorded gameplay video (vicarious playing while their hemodynamic brain activation was measured with 3-tesla functional magnetic resonance imaging (fMRI. Wins and losses were paired with symmetrical monetary rewards and punishments during active and vicarious playing so that the external reward context remained identical during both conditions. Brain activation was stronger in the orbitomedial prefrontal cortex (omPFC during winning than losing, both during active and vicarious playing conditions. In contrast, both wins and losses suppressed activations in the midbrain and striatum during active playing; however, the striatal suppression, particularly in the anterior putamen, was more pronounced during loss than win events. Sensorimotor confounds related to joystick movements did not account for the results. Self-ratings indicated losing to be more unpleasant during active than vicarious playing. Our findings demonstrate striatum to be selectively sensitive to self-acquired rewards, in contrast to frontal components of the reward circuit that process both self-acquired and passively received rewards. We propose that the striatal responses to repeated acquisition of rewards that are contingent on game related successes contribute to the motivational pull of video-game playing.

Vicarious calibration of the solar reflection channels of radiometers onboard satellites through the field campaigns with measurements of refractive index and size distribution of aerosols

Science.gov (United States)

Arai, K.

A comparative study on vicarious calibration for the solar reflection channels of radiometers onboard satellite through the field campaigns between with and without measurements of refractive index and size distribution of aerosols is made. In particular, it is noticed that the influence due to soot from the cars exhaust has to be care about for the test sites near by a heavy trafficked roads. It is found that the 0.1% inclusion of soot induces around 10% vicarious calibration error so that it is better to measure refractive index properly at the test site. It is found that the vicarious calibration coefficients with the field campaigns at the different test site, Ivanpah (near road) and Railroad (distant from road) shows approximately 10% discrepancy. It seems that one of the possible causes for the difference is the influence due to soot from cars exhaust.

Asymmetries in Experiential and Vicarious Feedback: Lessons from the Hiring and Firing of Baseball Managers

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David Strang

2014-05-01

Full Text Available We examine experiential and vicarious feedback in the hiring and firing of baseball managers. Realized outcomes play a large role in both decisions; the probability that a manager will be fired is a function of the team’s win–loss record, and a manager is quicker to be rehired if his teams had won more in the past. There are substantial asymmetries, however, in the fine structure of the two feedback functions. The rate at which managers are fired is powerfully shaped by recent outcomes, falls with success and rises with failure, and adjusts for history-based expectations. By contrast, hiring reflects a longer-term perspective that emphasizes outcomes over the manager’s career as well as the most recent campaign, rewards success but does not penalize failure, and exhibits no adjustment for historical expectations. We explain these asymmetries in terms of the disparate displays of rationality that organizations enact in response to their own outcomes versus those of others. Experiential feedback is conditioned by a logic of accountability, vicarious feedback by a logic of emulation.

Vicarious Calibration of Beijing-1 Multispectral Imagers

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Zhengchao Chen

2014-02-01

Full Text Available For on-orbit calibration of the Beijing-1 multispectral imagers (Beijing-1/MS, a field calibration campaign was performed at the Dunhuang calibration site during September and October of 2008. Based on the in situ data and images from Beijing-1 and Terra/Moderate Resolution Imaging Spectroradiometer (MODIS, three vicarious calibration methods (i.e., reflectance-based, irradiance-based, and cross-calibration were used to calculate the top-of-atmosphere (TOA radiance of Beijing-1. An analysis was then performed to determine or identify systematic and accidental errors, and the overall uncertainty was assessed for each individual method. The findings show that the reflectance-based method has an uncertainty of more than 10% if the aerosol optical depth (AOD exceeds 0.2. The cross-calibration method is able to reach an error level within 7% if the images are selected carefully. The final calibration coefficients were derived from the irradiance-based data for 6 September 2008, with an uncertainty estimated to be less than 5%.

Hybrid E-Learning Tool TransLearning: Video Storytelling to Foster Vicarious Learning within Multi-Stakeholder Collaboration Networks

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van der Meij, Marjoleine G.; Kupper, Frank; Beers, Pieter J.; Broerse, Jacqueline E. W.

2016-01-01

E-learning and storytelling approaches can support informal vicarious learning within geographically widely distributed multi-stakeholder collaboration networks. This case study evaluates hybrid e-learning and video-storytelling approach "TransLearning" by investigation into how its storytelling e-tool supported informal vicarious…

Learning from the Pros: Influence of Web-Based Expert Commentary on Vicarious Learning about Financial Markets

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Ford, Matthew W.; Kent, Daniel W.; Devoto, Steven

2007-01-01

Web-based financial commentary, in which experts routinely express market-related thought processes, is proposed as a means for college students to learn vicariously about financial markets. Undergraduate business school students from a regional university were exposed to expert market commentary from a single financial Web site for a 6-week…

Macaque monkeys can learn token values from human models through vicarious reward.

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Bevacqua, Sara; Cerasti, Erika; Falcone, Rossella; Cervelloni, Milena; Brunamonti, Emiliano; Ferraina, Stefano; Genovesio, Aldo

2013-01-01

Monkeys can learn the symbolic meaning of tokens, and exchange them to get a reward. Monkeys can also learn the symbolic value of a token by observing conspecifics but it is not clear if they can learn passively by observing other actors, e.g., humans. To answer this question, we tested two monkeys in a token exchange paradigm in three experiments. Monkeys learned token values through observation of human models exchanging them. We used, after a phase of object familiarization, different sets of tokens. One token of each set was rewarded with a bit of apple. Other tokens had zero value (neutral tokens). Each token was presented only in one set. During the observation phase, monkeys watched the human model exchange tokens and watched them consume rewards (vicarious rewards). In the test phase, the monkeys were asked to exchange one of the tokens for food reward. Sets of three tokens were used in the first experiment and sets of two tokens were used in the second and third experiments. The valuable token was presented with different probabilities in the observation phase during the first and second experiments in which the monkeys exchanged the valuable token more frequently than any of the neutral tokens. The third experiments examined the effect of unequal probabilities. Our results support the view that monkeys can learn from non-conspecific actors through vicarious reward, even a symbolic task like the token-exchange task.

Vicarious traumatization in the work with survivors of childhood trauma.

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Crothers, D

1995-04-01

1. Persons working with victims of childhood trauma may experience traumatic countertransference and vicarious traumatization. After hearing a patient's trauma story, which is a necessary part of childhood trauma therapy, staff may experience post-traumatic stress disorder, imagery associated with the patient's story and the same disruptions in relationships as the patient. 2. During the first 6 months of working with survivors of childhood trauma, common behaviors of staff members were identified, including a lack of attention, poor work performance, medication errors, sick calls, treatment errors, irreverence, hypervigilance, and somatic complaints. 3. Staff working with victims of childhood trauma can obtain the necessary staff support through team support, in traumatic events, and in a leadership role.

Interpreters’ Experiences of Transferential Dynamics, Vicarious Traumatisation, and Their Need for Support and Supervision: A Systematic Literature Review

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Emma Darroch

2016-08-01

Full Text Available Using thematic analysis, this systematic review aimed to explore sign language interpreters’ experiences of transferential dynamics and vicarious trauma. The notion of transferential dynamics, such as transference and countertransference, originate from psychodynamic therapy and refer to the mutual impact that client and therapist have on one another (Chessick, 1986. Psychodynamic models of therapy are predominantly concerned with unconscious processes and theorise that such processes have a powerful influence over an individuals’ thoughts, feelings and behaviours (Howard, 2011. In contrast to countertransference, which is a immediate response to a particular client, vicarious trauma is thought to develop as a result of continuous exposure to, and engagement across, many therapeutic interactions (Pearlman & Saakvitne, 1995a. A search of the available literature uncovered a striking lack of literature into the experiences of sign language interpreters, and in all, only two of the 11 identified empirical studies addressed sign language interpreters. The vast majority of the literature analysed reflected the experiences of spoken language interpreters. The results indicate that interpreters experience transferential dynamics as part of their work as well as suggesting the presence of vicarious trauma among interpreters. Additionally, a unique contribution to the fields of interpreting and psychology is offered, as it is consistently demonstrated that ‘service providers’ and ‘mental health workers’, which are umbrella terms for psychologists, immensely under-estimate the role of interpreters, as they fail to consider the emotional impact of their work and ignore the linguistic complexities of translation by failing to appreciate their need for information in order to ensure an effective translation.

Dental Hypotheses: Seeks to Publish Hypotheses from All Areas of Dentistry

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Edward F. Rossomando

2010-07-01

Full Text Available Starting a new open access journal in a rapid growing scientific panorama is a severe challenge. However, the first issue of dental hypotheses is now history and the even skeptics can appreciate that dental hypotheses is a success - it is a journal of high quality that provides an outlet for publication of articles that encourage readers to question dental paradigms. But dental hypotheses readers might have noticed that the majority of the articles published in the first issue of dental hypotheses concern clinical dentistry. However, dental hypotheses editors recognize that there are many other areas in dentistry that present challenges and that our readers may offer suggestions for their solution. Some of these challenges relate to: dental education; digital dental technology; teledentistry and access to dental care; dental practice issues, such as, dental office design, dental office management, the slow rate of acceptance of innovative technology in the dental office; and issues related to innovation and dental entrepreneurship including intellectual property protection. Nevertheless, the dental profession faces many challenges - in many areas - and with the publication of dental hypotheses our profession has a venue for presentation of possible solutions. If you have developed a hypothesis that might help, please share it with your colleagues. As many have noted, the intellectual power of the global village in which we now live is formidable. The internet has provided the technology to bring us together and dental hypotheses has provided the venue. Please use it. New radical, speculative and non-mainstream scientific ideas are always welcome.

Career Coaches as a Source of Vicarious Learning for Racial and Ethnic Minority PhD Students in the Biomedical Sciences: A Qualitative Study.

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Williams, Simon N; Thakore, Bhoomi K; McGee, Richard

2016-01-01

Many recent mentoring initiatives have sought to help improve the proportion of underrepresented racial and ethnic minorities (URMs) in academic positions across the biomedical sciences. However, the intractable nature of the problem of underrepresentation suggests that many young scientists may require supplemental career development beyond what many mentors are able to offer. As an adjunct to traditional scientific mentoring, we created a novel academic career "coaching" intervention for PhD students in the biomedical sciences. To determine whether and how academic career coaches can provide effective career-development-related learning experiences for URM PhD students in the biomedical sciences. We focus specifically on vicarious learning experiences, where individuals learn indirectly through the experiences of others. The intervention is being tested as part of a longitudinal randomized control trial (RCT). Here, we describe a nested qualitative study, using a framework approach to analyze data from a total of 48 semi-structured interviews from 24 URM PhD students (2 interviews per participant, 1 at baseline, 1 at 12-month follow-up) (16 female, 8 male; 11 Black, 12 Hispanic, 1 Native-American). We explored the role of the coach as a source of vicarious learning, in relation to the students' goal of being future biomedical science faculty. Coaches were resources through which most students in the study were able to learn vicariously about how to pursue, and succeed within, an academic career. Coaches were particularly useful in instances where students' research mentors are unable to provide such vicarious learning opportunities, for example because the mentor is too busy to have career-related discussions with a student, or because they have, or value, a different type of academic career to the type the student hopes to achieve. Coaching can be an important way to address the lack of structured career development that students receive in their home training

Vicarious Radiometric Calibration of a Multispectral Camera on Board an Unmanned Aerial System

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Susana Del Pozo

2014-02-01

Full Text Available Combinations of unmanned aerial platforms and multispectral sensors are considered low-cost tools for detailed spatial and temporal studies addressing spectral signatures, opening a broad range of applications in remote sensing. Thus, a key step in this process is knowledge of multi-spectral sensor calibration parameters in order to identify the physical variables collected by the sensor. This paper discusses the radiometric calibration process by means of a vicarious method applied to a high-spatial resolution unmanned flight using low-cost artificial and natural covers as control and check surfaces, respectively.

Impact of Vicarious Learning Experiences and Goal Setting on Preservice Teachers' Self-Efficacy for Technology Integration: A Pilot Study.

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Wang, Ling; Ertmer, Peggy A.

This pilot study was designed to explore how vicarious learning experiences and goal setting influence preservice teachers' self-efficacy for integrating technology into the classroom. Twenty undergraduate students who were enrolled in an introductory educational technology course at a large midwestern university participated and were assigned…

Invasive species and biodiversity crises: testing the link in the late devonian.

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Alycia L Stigall

Full Text Available During the Late Devonian Biodiversity Crisis, the primary driver of biodiversity decline was the dramatic reduction in speciation rates, not elevated extinction rates; however, the causes of speciation decline have been previously unstudied. Speciation, the formation of new species from ancestral populations, occurs by two primary allopatric mechanisms: vicariance, where the ancestral population is passively divided into two large subpopulations that later diverge and form two daughter species, and dispersal, in which a small subset of the ancestral population actively migrates then diverges to form a new species. Studies of modern and fossil clades typically document speciation by vicariance in much higher frequencies than speciation by dispersal. To assess the mechanism behind Late Devonian speciation reduction, speciation rates were calculated within stratigraphically constrained species-level phylogenetic hypotheses for three representative clades and mode of speciation at cladogenetic events was assessed across four clades in three phyla: Arthropoda, Brachiopoda, and Mollusca. In all cases, Devonian taxa exhibited a congruent reduction in speciation rate between the Middle Devonian pre-crisis interval and the Late Devonian crisis interval. Furthermore, speciation via vicariance is almost entirely absent during the crisis interval; most episodes of speciation during this time were due to dispersal. The shutdown of speciation by vicariance during this interval was related to widespread interbasinal species invasions. The lack of Late Devonian vicariance is diametrically opposed to the pattern observed in other geologic intervals, which suggests the loss of vicariant speciation attributable to species invasions during the Late Devonian was a causal factor in the biodiversity crisis. Similarly, modern ecosystems, in which invasive species are rampant, may be expected to exhibit similar shutdown of speciation by vicariance as an outcome of the

Invasive species and biodiversity crises: testing the link in the late devonian.

Science.gov (United States)

Stigall, Alycia L

2010-12-29

During the Late Devonian Biodiversity Crisis, the primary driver of biodiversity decline was the dramatic reduction in speciation rates, not elevated extinction rates; however, the causes of speciation decline have been previously unstudied. Speciation, the formation of new species from ancestral populations, occurs by two primary allopatric mechanisms: vicariance, where the ancestral population is passively divided into two large subpopulations that later diverge and form two daughter species, and dispersal, in which a small subset of the ancestral population actively migrates then diverges to form a new species. Studies of modern and fossil clades typically document speciation by vicariance in much higher frequencies than speciation by dispersal. To assess the mechanism behind Late Devonian speciation reduction, speciation rates were calculated within stratigraphically constrained species-level phylogenetic hypotheses for three representative clades and mode of speciation at cladogenetic events was assessed across four clades in three phyla: Arthropoda, Brachiopoda, and Mollusca. In all cases, Devonian taxa exhibited a congruent reduction in speciation rate between the Middle Devonian pre-crisis interval and the Late Devonian crisis interval. Furthermore, speciation via vicariance is almost entirely absent during the crisis interval; most episodes of speciation during this time were due to dispersal. The shutdown of speciation by vicariance during this interval was related to widespread interbasinal species invasions. The lack of Late Devonian vicariance is diametrically opposed to the pattern observed in other geologic intervals, which suggests the loss of vicariant speciation attributable to species invasions during the Late Devonian was a causal factor in the biodiversity crisis. Similarly, modern ecosystems, in which invasive species are rampant, may be expected to exhibit similar shutdown of speciation by vicariance as an outcome of the modern biodiversity

Not My Problem: Vicarious Conflict Adaptation with Human and Virtual Co-Actors

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Michiel M. Spapé

2016-04-01

Full Text Available The Simon effect refers to an incompatibility between stimulus and response locations resulting in a conflict situation and, consequently, slower responses. Like other conflict effects, it is commonly reduced after repetitions, suggesting an executive control ability, which flexibly rewires cognitive processing and adapts to conflict. Interestingly, conflict is not necessarily individually defined: the Social Simon effect refers to a scenario where two people who share a task show a conflict effect where a single person does not. Recent studies showed these observations might converge into what could be called vicarious conflict adaptation, with evidence indicating that observing someone else’s conflict may subsequently reduce one’s own. While plausible, there is reason for doubt: both the social aspect of the Simon Effect, and the degree to which executive control accounts for the conflict adaptation effect, have become foci of debate in recent studies. Here, we present two experiments that were designed to test the social dimension of the effect by varying the social relationship between the actor and the co-actor. In Experiment 1, participants performed a conflict task with a virtual co-actor, while the actor-observer relationship was manipulated as a function of the similarity between response modalities. In Experiment 2, the same task was performed both with a virtual and with a human co-actor, while heart-rate measurements were taken to measure the impact of observed conflict on autonomous activity. While both experiments replicated the interpersonal conflict adaptation effects, neither showed evidence of the critical social dimension. We consider the findings as demonstrating that vicarious conflict adaptation does not rely on the social relationship between the actor and co-actor.

The Human Factor: Behavioral and Neural Correlates of Humanized Perception in Moral Decision Making

OpenAIRE

Majdandžić, Jasminka; Bauer, Herbert; Windischberger, Christian; Moser, Ewald; Engl, Elisabeth; Lamm, Claus

2012-01-01

The extent to which people regard others as full-blown individuals with mental states ("humanization") seems crucial for their prosocial motivation towards them. Previous research has shown that decisions about moral dilemmas in which one person can be sacrificed to save multiple others do not consistently follow utilitarian principles. We hypothesized that this behavior can be explained by the potential victim's perceived humanness and an ensuing increase in vicarious emotions and emotional ...

In silico generation of alternative hypotheses using causal mapping (CMAP.

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Gabriel E Weinreb

Full Text Available Previously, we introduced causal mapping (CMAP as an easy to use systems biology tool for studying the behavior of biological processes that occur at the cellular and molecular level. CMAP is a coarse-grained graphical modeling approach in which the system of interest is modeled as an interaction map between functional elements of the system, in a manner similar to portrayals of signaling pathways commonly used by molecular cell biologists. CMAP describes details of the interactions while maintaining the simplicity of other qualitative methods (e.g., Boolean networks.In this paper, we use the CMAP methodology as a tool for generating hypotheses about the mechanisms that regulate molecular and cellular systems. Furthermore, our approach allows competing hypotheses to be ranked according to a fitness index and suggests experimental tests to distinguish competing high fitness hypotheses. To motivate the CMAP as a hypotheses generating tool and demonstrate the methodology, we first apply this protocol to a simple test-case of a three-element signaling module. Our methods are next applied to the more complex phenomenon of cortical oscillations observed in spreading cells. This analysis produces two high fitness hypotheses for the mechanism that underlies this dynamic behavior and suggests experiments to distinguish the hypotheses. The method can be widely applied to other cellular systems to generate and compare alternative hypotheses based on experimentally observed data and using computer simulations.

An analysis of dinosaurian biogeography: evidence for the existence of vicariance and dispersal patterns caused by geological events.

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Upchurch, Paul; Hunn, Craig A; Norman, David B

2002-03-22

As the supercontinent Pangaea fragmented during the Mesozoic era, dinosaur faunas were divided into isolated populations living on separate continents. It has been predicted, therefore, that dinosaur distributions should display a branching ('vicariance') pattern that corresponds with the sequence and timing of continental break-up. Several recent studies, however, minimize the importance of plate tectonics and instead suggest that dispersal and regional extinction were the main controls on dinosaur biogeography. Here, in order to test the vicariance hypothesis, we apply a cladistic biogeographical method to a large dataset on dinosaur relationships and distributions. We also introduce a methodological refinement termed 'time-slicing', which is shown to be a key step in the detection of ancient biogeographical patterns. These analyses reveal biogeographical patterns that closely correlate with palaeogeography. The results provide the first statistically robust evidence that, from Middle Jurassic to mid-Cretaceous times, tectonic events had a major role in determining where and when particular dinosaur groups flourished. The fact that evolutionary trees for extinct organisms preserve such distribution patterns opens up a new and fruitful direction for palaeobiogeographical research.

Global biogeography of scaly tree ferns (Cyatheaceae): evidence for Gondwanan vicariance and limited transoceanic dispersal

OpenAIRE

Korall, Petra; Pryer, Kathleen

2014-01-01

Aim Scaly tree ferns, Cyatheaceae, are a well-supported group of mostly tree-forming ferns found throughout the tropics, the subtropics and the south-temperate zone. Fossil evidence shows that the lineage originated in the Late Jurassic period. We reconstructed large-scale historical biogeographical patterns of Cyatheaceae and tested the hypothesis that some of the observed distribution patterns are in fact compatible, in time and space, with a vicariance scenario related to the break-up of G...

Vicarious traumatization and coping in medical students: a pilot study.

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Al-Mateen, Cheryl S; Linker, Julie A; Damle, Neha; Hupe, Jessica; Helfer, Tamara; Jessick, Veronica

2015-02-01

This study explored the impact of traumatic experiences on medical students during their clerkships. Medical students completed an anonymous online survey inquiring about traumatic experiences on required clerkships during their third year of medical school, including any symptoms they may have experienced as well as coping strategies they may have used. Twenty-six percent of students reported experiencing vicarious traumatization (VT) during their third year of medical school. The experience of VT in medical students is relevant to medical educators, given that the resulting symptoms may impact student performance and learning as well as ongoing well-being. Fifty percent of the students who experienced VT in this study did so on the psychiatry clerkship. It is important for psychiatrists to recognize that this is a potential risk for students in order to increase the likelihood that appropriate supports are provided.

Effects of MK-801 on vicarious trial-and-error and reversal of olfactory discrimination learning in weanling rats.

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Griesbach, G S; Hu, D; Amsel, A

1998-12-01

The effects of dizocilpine maleate (MK-801) on vicarious trial-and-error (VTE), and on simultaneous olfactory discrimination learning and its reversal, were observed in weanling rats. The term VTE was used by Tolman (The determiners of behavior at a choice point. Psychol. Rev. 1938;46:318-336), who described it as conflict-like behavior at a choice-point in simultaneous discrimination learning. It takes the form of head movements from one stimulus to the other, and has recently been proposed by Amsel (Hippocampal function in the rat: cognitive mapping or vicarious trial-and-error? Hippocampus, 1993;3:251-256) as related to hippocampal, nonspatial function during this learning. Weanling male rats received systemic MK-801 either 30 min before the onset of olfactory discrimination training and its reversal, or only before its reversal. The MK-801-treated animals needed significantly more sessions to acquire the discrimination and showed significantly fewer VTEs in the acquisition phase of learning. Impaired reversal learning was shown only when MK-801 was administered during the reversal-learning phase, itself, and not when it was administered throughout both phases.

Testosterone and estrogen impact social evaluations and vicarious emotions: A double-blind placebo-controlled study.

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Olsson, Andreas; Kopsida, Eleni; Sorjonen, Kimmo; Savic, Ivanka

2016-06-01

The abilities to "read" other peoples' intentions and emotions, and to learn from their experiences, are critical to survival. Previous studies have highlighted the role of sex hormones, notably testosterone and estrogen, in these processes. Yet it is unclear how these hormones affect social cognition and emotion using acute hormonal administration. In the present double-blind placebo-controlled study, we administered an acute exogenous dose of testosterone or estrogen to healthy female and male volunteers, respectively, with the aim of investigating the effects of these steroids on social-cognitive and emotional processes. Following hormonal and placebo treatment, participants made (a) facial dominance judgments, (b) mental state inferences (Reading the Mind in the Eyes Test), and (c) learned aversive associations through watching others' emotional responses (observational fear learning [OFL]). Our results showed that testosterone administration to females enhanced ratings of facial dominance but diminished their accuracy in inferring mental states. In men, estrogen administration resulted in an increase in emotional (vicarious) reactivity when watching a distressed other during the OFL task. Taken together, these results suggest that sex hormones affect social-cognitive and emotional functions at several levels, linking our results to neuropsychiatric disorders in which these functions are impaired. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Transoceanic Dispersal and Plate Tectonics Shaped Global Cockroach Distributions: Evidence from Mitochondrial Phylogenomics.

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Bourguignon, Thomas; Tang, Qian; Ho, Simon Y W; Juna, Frantisek; Wang, Zongqing; Arab, Daej A; Cameron, Stephen L; Walker, James; Rentz, David; Evans, Theodore A; Lo, Nathan

2017-04-01

Following the acceptance of plate tectonics theory in the latter half of the 20th century, vicariance became the dominant explanation for the distributions of many plant and animal groups. In recent years, however, molecular-clock analyses have challenged a number of well-accepted hypotheses of vicariance. As a widespread group of insects with a fossil record dating back 300 My, cockroaches provide an ideal model for testing hypotheses of vicariance through plate tectonics versus transoceanic dispersal. However, their evolutionary history remains poorly understood, in part due to unresolved relationships among the nine recognized families. Here, we present a phylogenetic estimate of all extant cockroach families, as well as a timescale for their evolution, based on the complete mitochondrial genomes of 119 cockroach species. Divergence dating analyses indicated that the last common ancestor of all extant cockroaches appeared ∼235 Ma, ∼95 My prior to the appearance of fossils that can be assigned to extant families, and before the breakup of Pangaea began. We reconstructed the geographic ranges of ancestral cockroaches and found tentative support for vicariance through plate tectonics within and between several major lineages. We also found evidence of transoceanic dispersal in lineages found across the Australian, Indo-Malayan, African, and Madagascan regions. Our analyses provide evidence that both vicariance and dispersal have played important roles in shaping the distribution and diversity of these insects.

Direct and vicarious violent victimization and juvenile delinquency: an application of general strain theory.

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Lin, Wen-Hsu; Cochran, John K; Mieczkowski, Thomas

2011-01-01

Using a national probability sample of adolescents (12–17), this study applies general strain theory to how violent victimization, vicarious violent victimization, and dual violent victimization affect juvenile violent/property crime and drug use. In addition, the mediating effect and moderating effect of depression, low social control, and delinquent peer association on the victimization–delinquency relationship is also examined. Based on SEM analyses and contingency tables, the results indicate that all three types of violent victimization have significant and positive direct effects on violent/property crime and drug use. In addition, the expected mediating effects and moderating effects are also found. Limitations and future directions are discussed.

Explanatory hypotheses formation and the anomalous β spectrum

Energy Technology Data Exchange (ETDEWEB)

Gauderis, Tjerk [Centre for Logic and Philosophy of Science, Ghent University (Belgium)

2013-07-01

Between 1928 and 1934, a persevering anomaly mystified the physics community: while alpha decay behaved perfectly according to the new quantum mechanics, the energy of electrons emitted in beta decay displayed a broad continuous spectrum. This puzzle invoked a lively debate among the most established physicists at the time. But the curious thing was that they all suggested hypotheses of very different formal types: Rutherford and Chadwick thought of varying internal energies, Bohr suggested to restrict the energy conservation principle, Heisenberg tinkered with a new quantization of space, and Pauli suggested the existence of a new elementary particle - all these hypotheses being radical and highly controversial. In physics, an anomalous experimental result can trigger the formation of formally very different hypotheses. A scientist confronted with such a result has no strict guidelines to help her decide whether she should explain this result by withdrawing or adapting a constraint (e.g. a law) of the current theory, or by presupposing the existence of a hitherto unobserved entity (e.g. a particle) that makes the anomaly fit within that theory. In this talk I aim to gain some insights how scientists make this choice, by examining in the above case study how the choice of the various mentioned physicists depended on their previous experiences and their specific perception of the problem.

ITSSOIN Hypotheses

NARCIS (Netherlands)

Anheier, H.K.; Krlev, G.; Preuss, S.; Mildenberger, G.; Bekkers, R.H.F.P.; Brink Lund, A.

2014-01-01

This report brings together findings from the first ITSSOIN project working steps to formulate empirically testable hypotheses on the impact of the third sector and social innovation – in particular regarding the role of the third sector in generating social innovation but also with reference to

Glacial vicariance in the Pacific Northwest: evidence from a lodgepole pine mitochondrial DNA minisatellite for multiple genetically distinct and widely separated refugia.

Science.gov (United States)

Godbout, Julie; Fazekas, Aron; Newton, Craig H; Yeh, Francis C; Bousquet, Jean

2008-05-01

The Canadian side of the Pacific Northwest was almost entirely covered by ice during the last glacial maximum, which has induced vicariance and genetic population structure for several plant and animal taxa. Lodgepole pine (Pinus contorta Dougl. ex. Loud.) has a wide latitudinal and longitudinal distribution in the Pacific Northwest. Our main objective was to identify relictual signatures of glacial vicariance in the population structure of the species and search for evidence of distinct glacial refugia in the Pacific Northwest. A maternally inherited mitochondrial DNA minisatellite-like marker was used to decipher haplotype diversity in 91 populations of lodgepole pine located across the natural range. Overall population differentiation was sizeable (G(ST) = 0.365 and R(ST) = 0.568). Four relatively homogeneous groups of populations, possibly representative of as many genetically distinct glacial populations, were identified for the two main subspecies, ssp. latifolia and ssp. contorta. For ssp. contorta, one glacial lineage is suggested to have been located at high latitudes and possibly off the coast of mainland British Columbia (BC), while the other is considered to have been located south of the ice sheet along the Pacific coast. For ssp. latifolia, two genetically distinct glacial populations probably occurred south of the ice sheet: in the area bounded by the Cascades and Rocky Mountains ranges, and on the eastern side of the Rockies. A possible fifth refugium located in the Yukon may have also been present for ssp. latifolia. Zones of contact between these ancestral lineages were also apparent in interior and northern BC. These results indicate the role of the Queen Charlotte Islands and the Alexander Archipelago as a refugial zone for some Pacific Northwest species and the vicariant role played by the Cascades and the American Rocky Mountains during glaciation.

Testing hypotheses in order

OpenAIRE

Paul R. Rosenbaum

2008-01-01

In certain circumstances, one wishes to test one hypothesis only if certain other hypotheses have been rejected. This ordering of hypotheses simplifies the task of controlling the probability of rejecting any true hypothesis. In an example from an observational study, a treated group is shown to be further from both of two control groups than the two control groups are from each other. Copyright 2008, Oxford University Press.

ADOPTING SOCIO-DEMOGRAPHIC CHARACTERISTICS IN PROFILING GREEN CONSUMERS: A REVIEW OF HYPOTHESES

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Arif Hartono

2009-02-01

Full Text Available In the last three decades worldwide environmental consciousness has increased dramatically as well as profiling green consumers have gained tremendous attention in the past. Segmenting and targeting markets base on pro-environmental purchase behavior are essential when companies positioning their green products. Socio-demographic characteristics have gained a lot of attention as the key profiling variables. Such characteristics have been employed by many scholars more frequently for the bases of segmenting and profiling green consumers. However, most existing studies of green consumers’ socio-demographic were US based. The present article attempts to review the common hypotheses of socio-demographic characteristics in profiling green consumers. The present article reviews five general hypotheses relating to socio-demographics and environmental consciousness of green consumers, namely the gender, age, education level, income, and occupation hypotheses, as well as the theoretical explanation for each hypothesis. Most previous studies tend to have the same conclusion in the gender, age, education level, and  income characteristics. Critics to socio-demographic characteristics and a need to conduct green marketing research in Indonesia was also reviewed.Key words: profiling, socio-demographic, green consumer, hypotheses.

Treating fossils as terminal taxa in divergence time estimation reveals ancient vicariance patterns in the palpimanoid spiders.

Science.gov (United States)

Wood, Hannah Marie; Matzke, Nicholas J; Gillespie, Rosemary G; Griswold, Charles E

2013-03-01

Incorporation of fossils into biogeographic studies can have a profound effect on the conclusions that result, particularly when fossil ranges are nonoverlapping with extant ranges. This is the case in archaeid spiders, where there are known fossils from the Northern Hemisphere, yet all living members are restricted to the Southern Hemisphere. To better understand the biogeographic patterns of archaeid spiders and their palpimanoid relatives, we estimate a dated phylogeny using a relaxed clock on a combined molecular and morphological data set. Dating information is compared with treating the archaeid fossil taxa as both node calibrations and as noncontemporaneous terminal tips, both with and without additional calibration points. Estimation of ancestral biogeographic ranges is then performed, using likelihood and Bayesian methods to take into account uncertainty in phylogeny and in dating. We find that treating the fossils as terminal tips within a Bayesian framework, as opposed to dating the phylogeny based only on molecular data with the dates coming from node calibrations, removes the subjectivity involved in assigning priors, which has not been possible with previous methods. Our analyses suggest that the diversification of the northern and southern archaeid lineages was congruent with the breakup of Pangaea into Laurasia and Gondwanaland. This analysis provides a rare example, and perhaps the most strongly supported, where a dated phylogeny confirms a biogeographical hypothesis based on vicariance due to the breakup of the ancient continental plates.

Phylogeography of the common vampire bat (Desmodus rotundus: Marked population structure, Neotropical Pleistocene vicariance and incongruence between nuclear and mtDNA markers

Directory of Open Access Journals (Sweden)

Morgante João S

2009-12-01

Full Text Available Abstract Background The common vampire bat Desmodus rotundus is an excellent model organism for studying ecological vicariance in the Neotropics due to its broad geographic range and its preference for forested areas as roosting sites. With the objective of testing for Pleistocene ecological vicariance, we sequenced a mitocondrial DNA (mtDNA marker and two nuclear markers (RAG2 and DRB to try to understand how Pleistocene glaciations affected the distribution of intraspecific lineages in this bat. Results Five reciprocally monophyletic clades were evident in the mitochondrial gene tree, and in most cases with high bootstrap support: Central America (CA, Amazon and Cerrado (AMC, Pantanal (PAN, Northern Atlantic Forest (NAF and Southern Atlantic Forest (SAF. The Atlantic forest clades formed a monophyletic clade with high bootstrap support, creating an east/west division for this species in South America. On the one hand, all coalescent and non-coalescent estimates point to a Pleistocene time of divergence between the clades. On the other hand, the nuclear markers showed extensive sharing of haplotypes between distant localities, a result compatible with male-biased gene flow. In order to test if the disparity between the mitochondrial and nuclear markers was due to the difference in mutation rate and effective size, we performed a coalescent simulation to examine the feasibility that, given the time of separation between the observed lineages, even with a gene flow rate close to zero, there would not be reciprocal monophyly for a neutral nuclear marker. We used the observed values of theta and an estimated mutation rate for the nuclear marker gene to perform 1000 iterations of the simulation. The results of this simulation were inconclusive: the number of iterations with and without reciprocal monophyly of one or more clades are similar. Conclusions We therefore conclude that the pattern exhibited by the common vampire bat, with marked

Using modeling and vicarious reinforcement to produce more positive attitudes toward mental health treatment.

Science.gov (United States)

Buckley, Gary I; Malouff, John M

2005-05-01

In this study, the authors evaluated the effectiveness of a video, developed for this study and using principles of cognitive learning theory, to produce positive attitudinal change toward mental health treatment. The participants were 35 men and 45 women who were randomly assigned to watch either an experimental video, which included 3 positive 1st-person accounts of psychotherapy or a control video that focused on the psychological construct of self. Pre-intervention, post-intervention, and 2-week follow-up levels of attitude toward mental health treatment were measured using the Attitude Toward Seeking Professional Help Scale (E. H. Fischer & J. L. Turner, 1970). The experimental video group showed a significantly greater increase in positive attitude than did the control group. These results support the effectiveness of using the vicarious reinforcement elements of cognitive learning theory as a basis for changing attitudes toward mental health treatment.

New Vehicle Detection Method with Aspect Ratio Estimation for Hypothesized Windows

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Jisu Kim

2015-12-01

Full Text Available All kinds of vehicles have different ratios of width to height, which are called the aspect ratios. Most previous works, however, use a fixed aspect ratio for vehicle detection (VD. The use of a fixed vehicle aspect ratio for VD degrades the performance. Thus, the estimation of a vehicle aspect ratio is an important part of robust VD. Taking this idea into account, a new on-road vehicle detection system is proposed in this paper. The proposed method estimates the aspect ratio of the hypothesized windows to improve the VD performance. Our proposed method uses an Aggregate Channel Feature (ACF and a support vector machine (SVM to verify the hypothesized windows with the estimated aspect ratio. The contribution of this paper is threefold. First, the estimation of vehicle aspect ratio is inserted between the HG (hypothesis generation and the HV (hypothesis verification. Second, a simple HG method named a signed horizontal edge map is proposed to speed up VD. Third, a new measure is proposed to represent the overlapping ratio between the ground truth and the detection results. This new measure is used to show that the proposed method is better than previous works in terms of robust VD. Finally, the Pittsburgh dataset is used to verify the performance of the proposed method.

Vicarious trial-and-error behavior and hippocampal cytochrome oxidase activity during Y-maze discrimination learning in the rat.

Science.gov (United States)

Hu, Dan; Xu, Xiaojuan; Gonzalez-Lima, Francisco

2006-03-01

The present study investigated whether more vicarious trial-and-error (VTE) behavior, defined by head movement from one stimulus to another at a choice point during simultaneous discriminations, led to better visual discrimination learning in a Y-maze, and whether VTE behavior was a function of the hippocampus by measuring regional brain cytochrome oxidase (C.O.) activity, an index of neuronal metabolic activity. The results showed that the more VTEs a rat made, the better the rat learned the visual discrimination. Furthermore, both learning and VTE behavior during learning were correlated to C.O. activity in the hippocampus, suggesting that the hippocampus plays a role in VTE behavior during discrimination learning.

Spontaneous eye movements and trait empathy predict vicarious learning of fear.

Science.gov (United States)

Kleberg, Johan L; Selbing, Ida; Lundqvist, Daniel; Hofvander, Björn; Olsson, Andreas

2015-12-01

Learning to predict dangerous outcomes is important to survival. In humans, this kind of learning is often transmitted through the observation of others' emotional responses. We analyzed eye movements during an observational/vicarious fear learning procedure, in which healthy participants (N=33) watched another individual ('learning model') receiving aversive treatment (shocks) paired with a predictive conditioned stimulus (CS+), but not a control stimulus (CS-). Participants' gaze pattern towards the model differentiated as a function of whether the CS was predictive or not of a shock to the model. Consistent with our hypothesis that the face of a conspecific in distress can act as an unconditioned stimulus (US), we found that the total fixation time at a learning model's face increased when the CS+ was shown. Furthermore, we found that the total fixation time at the CS+ during learning predicted participants' conditioned responses (CRs) at a later test in the absence of the model. We also demonstrated that trait empathy was associated with stronger CRs, and that autistic traits were positively related to autonomic reactions to watching the model receiving the aversive treatment. Our results have implications for both healthy and dysfunctional socio-emotional learning. Copyright © 2015 Elsevier B.V. All rights reserved.

Specific Vicariance of Two Primeval Lowland Forest Lichen Indicators

Science.gov (United States)

Kubiak, Dariusz; Osyczka, Piotr

2017-06-01

To date, the lichens Chrysothrix candelaris and Varicellaria hemisphaerica have been classified as accurate primeval lowland forest indicators. Both inhabit particularly valuable remnants of oak-hornbeam forests in Europe, but tend toward a specific kind of vicariance on a local scale. The present study was undertaken to determine habitat factors responsible for this phenomenon and verify the indicative and conservation value of these lichens. The main spatial and climatic parameters that, along with forest structure, potentially affect their distribution patterns and abundance were analysed in four complexes with typical oak-hornbeam stands in NE Poland. Fifty plots of 400 m2 each were chosen for detailed examination of stand structure and epiphytic lichens directly associated with the indicators. The study showed that the localities of the two species barely overlap within the same forest community in a relatively small geographical area. The occurrence of Chrysothrix candelaris depends basically only on microhabitat space provided by old oaks and its role as an indicator of the ecological continuity of habitat is limited. Varicellaria hemisphaerica is not tree specific but a sufficiently high moisture of habitat is essential for the species and it requires forests with high proportion of deciduous trees in a wide landscape scale. Local landscape-level habitat continuity is more important for this species than the current age of forest stand. Regardless of the indicative value, localities of both lichens within oak-hornbeam forests deserve the special protection status since they form unique assemblages of exclusive epiphytes, including those with high conservation value.

Ultra-portable field transfer radiometer for vicarious calibration of earth imaging sensors

Science.gov (United States)

Thome, Kurtis; Wenny, Brian; Anderson, Nikolaus; McCorkel, Joel; Czapla-Myers, Jeffrey; Biggar, Stuart

2018-06-01

A small portable transfer radiometer has been developed as part of an effort to ensure the quality of upwelling radiance from test sites used for vicarious calibration in the solar reflective. The test sites are used to predict top-of-atmosphere reflectance relying on ground-based measurements of the atmosphere and surface. The portable transfer radiometer is designed for one-person operation for on-site field calibration of instrumentation used to determine ground-leaving radiance. The current work describes the detector- and source-based radiometric calibration of the transfer radiometer highlighting the expected accuracy and SI-traceability. The results indicate differences between the detector-based and source-based results greater than the combined uncertainties of the approaches. Results from recent field deployments of the transfer radiometer using a solar radiation based calibration agree with the source-based laboratory calibration within the combined uncertainties of the methods. The detector-based results show a significant difference to the solar-based calibration. The source-based calibration is used as the basis for a radiance-based calibration of the Landsat-8 Operational Land Imager that agrees with the OLI calibration to within the uncertainties of the methods.

Vicarious Calibration of sUAS Microbolometer Temperature Imagery for Estimation of Radiometric Land Surface Temperature

Directory of Open Access Journals (Sweden)

Alfonso Torres-Rua

2017-06-01

Full Text Available In recent years, the availability of lightweight microbolometer thermal cameras compatible with small unmanned aerial systems (sUAS has allowed their use in diverse scientific and management activities that require sub-meter pixel resolution. Nevertheless, as with sensors already used in temperature remote sensing (e.g., Landsat satellites, a radiance atmospheric correction is necessary to estimate land surface temperature. This is because atmospheric conditions at any sUAS flight elevation will have an adverse impact on the image accuracy, derived calculations, and study replicability using the microbolometer technology. This study presents a vicarious calibration methodology (sUAS-specific, time-specific, flight-specific, and sensor-specific for sUAS temperature imagery traceable back to NIST-standards and current atmospheric correction methods. For this methodology, a three-year data collection campaign with a sUAS called “AggieAir”, developed at Utah State University, was performed for vineyards near Lodi, California, for flights conducted at different times (early morning, Landsat overpass, and mid-afternoon” and seasonal conditions. From the results of this study, it was found that, despite the spectral response of microbolometer cameras (7.0 to 14.0 μm, it was possible to account for the effects of atmospheric and sUAS operational conditions, regardless of time and weather, to acquire accurate surface temperature data. In addition, it was found that the main atmospheric correction parameters (transmissivity and atmospheric radiance significantly varied over the course of a day. These parameters fluctuated the most in early morning and partially stabilized in Landsat overpass and in mid-afternoon times. In terms of accuracy, estimated atmospheric correction parameters presented adequate statistics (confidence bounds under ±0.1 for transmissivity and ±1.2 W/m2/sr/um for atmospheric radiance, with a range of RMSE below 1.0 W/m2/sr

A phylogenetic review of the African leaf chameleons: genus Rhampholeon (Chamaeleonidae): the role of vicariance and climate change in speciation.

Science.gov (United States)

Matthee, Conrad A; Tilbury, Colin R; Townsend, Ted

2004-09-22

The phylogenetic associations among 13 currently recognized African leaf chameleon species were investigated by making use of mitochondrial and nuclear DNA sequence data (44 taxa and 4145 characters). The gene tree indicates two divergent clades within Rhampholeon; this finding is congruent with previous morphological suggestions. The first clade (I) comprises three taxa (R. kerstenii, R. brevicaudatus and R. brachyurus) and is widely distributed in lowland forest and or non-forest biomes. The second clade (II) comprises the remaining Rhampholeon species and can be subdivided into three subclades. By contrast, most taxa belonging to clade II are confined to relict montane forest biotopes. Based on geographical, morphological and molecular evidence, it is suggested that the taxonomy of Rhampholeon be revised to include two genera (Rieppeleon and Rhampholeon) and three subgenera (Rhampholeon, Bicuspis and Rhinodigitum). There is a close correlation between geographical distribution and phylogenetic relatedness among Rhampholeon taxa, indicating that vicariance and climate change were possibly the most influential factors driving speciation in the group. A relaxed Bayesian clock suggests that speciation times coincided both with the northern movement of Africa, which caused the constriction of the pan African forest, and to rifting in east Africa ca. 20 Myr ago. Subsequent speciation among taxa was probably the result of gradual desiccation of forests between 20 and 5 Myr ago.

Quantitative linking hypotheses for infant eye movements.

Directory of Open Access Journals (Sweden)

Daniel Yurovsky

Full Text Available The study of cognitive development hinges, largely, on the analysis of infant looking. But analyses of eye gaze data require the adoption of linking hypotheses: assumptions about the relationship between observed eye movements and underlying cognitive processes. We develop a general framework for constructing, testing, and comparing these hypotheses, and thus for producing new insights into early cognitive development. We first introduce the general framework--applicable to any infant gaze experiment--and then demonstrate its utility by analyzing data from a set of experiments investigating the role of attentional cues in infant learning. The new analysis uncovers significantly more structure in these data, finding evidence of learning that was not found in standard analyses and showing an unexpected relationship between cue use and learning rate. Finally, we discuss general implications for the construction and testing of quantitative linking hypotheses. MATLAB code for sample linking hypotheses can be found on the first author's website.

Pearce element ratios: A paradigm for testing hypotheses

Science.gov (United States)

Russell, J. K.; Nicholls, Jim; Stanley, Clifford R.; Pearce, T. H.

Science moves forward with the development of new ideas that are encapsulated by hypotheses whose aim is to explain the structure of data sets or to expand existing theory. These hypotheses remain conjecture until they have been tested. In fact, Karl Popper advocated that a scientist's job does not finish with the creation of an idea but, rather, begins with the testing of the related hypotheses. In Popper's [1959] advocation it is implicit that there be tools with which we can test our hypotheses. Consequently, the development of rigorous tests for conceptual models plays a major role in maintaining the integrity of scientific endeavor [e.g., Greenwood, 1989].

HyQue: evaluating hypotheses using Semantic Web technologies

Directory of Open Access Journals (Sweden)

Callahan Alison

2011-05-01

Full Text Available Abstract Background Key to the success of e-Science is the ability to computationally evaluate expert-composed hypotheses for validity against experimental data. Researchers face the challenge of collecting, evaluating and integrating large amounts of diverse information to compose and evaluate a hypothesis. Confronted with rapidly accumulating data, researchers currently do not have the software tools to undertake the required information integration tasks. Results We present HyQue, a Semantic Web tool for querying scientific knowledge bases with the purpose of evaluating user submitted hypotheses. HyQue features a knowledge model to accommodate diverse hypotheses structured as events and represented using Semantic Web languages (RDF/OWL. Hypothesis validity is evaluated against experimental and literature-sourced evidence through a combination of SPARQL queries and evaluation rules. Inference over OWL ontologies (for type specifications, subclass assertions and parthood relations and retrieval of facts stored as Bio2RDF linked data provide support for a given hypothesis. We evaluate hypotheses of varying levels of detail about the genetic network controlling galactose metabolism in Saccharomyces cerevisiae to demonstrate the feasibility of deploying such semantic computing tools over a growing body of structured knowledge in Bio2RDF. Conclusions HyQue is a query-based hypothesis evaluation system that can currently evaluate hypotheses about the galactose metabolism in S. cerevisiae. Hypotheses as well as the supporting or refuting data are represented in RDF and directly linked to one another allowing scientists to browse from data to hypothesis and vice versa. HyQue hypotheses and data are available at http://semanticscience.org/projects/hyque.

HyQue: evaluating hypotheses using Semantic Web technologies

Science.gov (United States)

2011-01-01

Background Key to the success of e-Science is the ability to computationally evaluate expert-composed hypotheses for validity against experimental data. Researchers face the challenge of collecting, evaluating and integrating large amounts of diverse information to compose and evaluate a hypothesis. Confronted with rapidly accumulating data, researchers currently do not have the software tools to undertake the required information integration tasks. Results We present HyQue, a Semantic Web tool for querying scientific knowledge bases with the purpose of evaluating user submitted hypotheses. HyQue features a knowledge model to accommodate diverse hypotheses structured as events and represented using Semantic Web languages (RDF/OWL). Hypothesis validity is evaluated against experimental and literature-sourced evidence through a combination of SPARQL queries and evaluation rules. Inference over OWL ontologies (for type specifications, subclass assertions and parthood relations) and retrieval of facts stored as Bio2RDF linked data provide support for a given hypothesis. We evaluate hypotheses of varying levels of detail about the genetic network controlling galactose metabolism in Saccharomyces cerevisiae to demonstrate the feasibility of deploying such semantic computing tools over a growing body of structured knowledge in Bio2RDF. Conclusions HyQue is a query-based hypothesis evaluation system that can currently evaluate hypotheses about the galactose metabolism in S. cerevisiae. Hypotheses as well as the supporting or refuting data are represented in RDF and directly linked to one another allowing scientists to browse from data to hypothesis and vice versa. HyQue hypotheses and data are available at http://semanticscience.org/projects/hyque. PMID:21624158

HyQue: evaluating hypotheses using Semantic Web technologies.

Science.gov (United States)

Callahan, Alison; Dumontier, Michel; Shah, Nigam H

2011-05-17

Key to the success of e-Science is the ability to computationally evaluate expert-composed hypotheses for validity against experimental data. Researchers face the challenge of collecting, evaluating and integrating large amounts of diverse information to compose and evaluate a hypothesis. Confronted with rapidly accumulating data, researchers currently do not have the software tools to undertake the required information integration tasks. We present HyQue, a Semantic Web tool for querying scientific knowledge bases with the purpose of evaluating user submitted hypotheses. HyQue features a knowledge model to accommodate diverse hypotheses structured as events and represented using Semantic Web languages (RDF/OWL). Hypothesis validity is evaluated against experimental and literature-sourced evidence through a combination of SPARQL queries and evaluation rules. Inference over OWL ontologies (for type specifications, subclass assertions and parthood relations) and retrieval of facts stored as Bio2RDF linked data provide support for a given hypothesis. We evaluate hypotheses of varying levels of detail about the genetic network controlling galactose metabolism in Saccharomyces cerevisiae to demonstrate the feasibility of deploying such semantic computing tools over a growing body of structured knowledge in Bio2RDF. HyQue is a query-based hypothesis evaluation system that can currently evaluate hypotheses about the galactose metabolism in S. cerevisiae. Hypotheses as well as the supporting or refuting data are represented in RDF and directly linked to one another allowing scientists to browse from data to hypothesis and vice versa. HyQue hypotheses and data are available at http://semanticscience.org/projects/hyque.

Assessing hypotheses about nesting site occupancy dynamics

Science.gov (United States)

Bled, Florent; Royle, J. Andrew; Cam, Emmanuelle

2011-01-01

Hypotheses about habitat selection developed in the evolutionary ecology framework assume that individuals, under some conditions, select breeding habitat based on expected fitness in different habitat. The relationship between habitat quality and fitness may be reflected by breeding success of individuals, which may in turn be used to assess habitat quality. Habitat quality may also be assessed via local density: if high-quality sites are preferentially used, high density may reflect high-quality habitat. Here we assessed whether site occupancy dynamics vary with site surrogates for habitat quality. We modeled nest site use probability in a seabird subcolony (the Black-legged Kittiwake, Rissa tridactyla) over a 20-year period. We estimated site persistence (an occupied site remains occupied from time t to t + 1) and colonization through two subprocesses: first colonization (site creation at the timescale of the study) and recolonization (a site is colonized again after being deserted). Our model explicitly incorporated site-specific and neighboring breeding success and conspecific density in the neighborhood. Our results provided evidence that reproductively "successful'' sites have a higher persistence probability than "unsuccessful'' ones. Analyses of site fidelity in marked birds and of survival probability showed that high site persistence predominantly reflects site fidelity, not immediate colonization by new owners after emigration or death of previous owners. There is a negative quadratic relationship between local density and persistence probability. First colonization probability decreases with density, whereas recolonization probability is constant. This highlights the importance of distinguishing initial colonization and recolonization to understand site occupancy. All dynamics varied positively with neighboring breeding success. We found evidence of a positive interaction between site-specific and neighboring breeding success. We addressed local

Social learning theory and the effects of living arrangement on heavy alcohol use: results from a national study of college students.

Science.gov (United States)

Ward, Brian W; Gryczynski, Jan

2009-05-01

This study examined the relationship between living arrangement and heavy episodic drinking among college students in the United States. Using social learning theory as a framework, it was hypothesized that vicarious learning of peer and family alcohol-use norms would mediate the effects of living arrangement on heavy episodic drinking. Analyses were conducted using data from the 2001 Harvard School of Public Health College Alcohol Study, a national survey of full-time undergraduate students attending 4-year colleges or universities in the United States (N = 10,008). Logistic regression models examined the relationship between heavy episodic drinking and various measures of living arrangement and vicarious learning/social norms. Mediation of the effects of living arrangement was tested using both indirect and direct methods. Both student living arrangement and vicarious-learning/social-norm variables remained significant predictors of heavy episodic drinking in multivariate models when controlling for a variety of individual characteristics. Slight mediation of the effects of living arrangement on heavy episodic drinking by vicarious learning/social norms was confirmed for some measures. Although vicarious learning of social norms does appear to play a role in the association between living arrangement and alcohol use, other processes may underlie the relationship. These findings suggest that using theory alongside empirical evidence to inform the manipulation of living environments could present a promising policy strategy to reduce alcohol-related harm in collegiate contexts.

Phylogeny, biogeography and diversification patterns of side-necked turtles (Testudines: Pleurodira)

Science.gov (United States)

Langer, Max C.; Sterli, Juliana

2018-01-01

Pleurodires or side-necked turtles are today restricted to freshwater environments of South America, Africa–Madagascar and Australia, but in the past they were distributed much more broadly, being found also on Eurasia, India and North America, and marine environments. Two hypotheses were proposed to explain this distribution; in the first, vicariance would have shaped the current geographical distribution and, in the second, extinctions constrained a previously widespread distribution. Here, we aim to reconstruct pleurodiran biogeographic history and diversification patterns based on a new phylogenetic hypothesis recovered from the analysis of the largest morphological dataset yet compiled for the lineage, testing which biogeographical process prevailed during its evolutionary history. The resulting topology generally agrees with previous hypotheses of the group and shows that most diversification shifts were related to the exploration of new niches, e.g. littoral or marine radiations. In addition, as other turtles, pleurodires do not seem to have been much affected by either the Cretaceous–Palaeogene or the Eocene–Oligocene mass extinctions. The biogeographic analyses highlight the predominance of both anagenetic and cladogenetic dispersal events and support the importance of transoceanic dispersals as a more common driver of area changes than previously thought, agreeing with previous studies with other non-turtle lineages. PMID:29657780

Dissociable brain systems mediate vicarious learning of stimulus-response and action-outcome contingencies.

Science.gov (United States)

Liljeholm, Mimi; Molloy, Ciara J; O'Doherty, John P

2012-07-18

Two distinct strategies have been suggested to support action selection in humans and other animals on the basis of experiential learning: a goal-directed strategy that generates decisions based on the value and causal antecedents of action outcomes, and a habitual strategy that relies on the automatic elicitation of actions by environmental stimuli. In the present study, we investigated whether a similar dichotomy exists for actions that are acquired vicariously, through observation of other individuals rather than through direct experience, and assessed whether these strategies are mediated by distinct brain regions. We scanned participants with functional magnetic resonance imaging while they performed an observational learning task designed to encourage either goal-directed encoding of the consequences of observed actions, or a mapping of observed actions to conditional discriminative cues. Activity in different parts of the action observation network discriminated between the two conditions during observational learning and correlated with the degree of insensitivity to outcome devaluation in subsequent performance. Our findings suggest that, in striking parallel to experiential learning, neural systems mediating the observational acquisition of actions may be dissociated into distinct components: a goal-directed, outcome-sensitive component and a less flexible stimulus-response component.

Drought responses of three closely related Caragana species: implication for their vicarious distribution.

Science.gov (United States)

Ma, Fei; Na, Xiaofan; Xu, Tingting

2016-05-01

Drought is a major environmental constraint affecting growth and distribution of plants in the desert region of the Inner Mongolia plateau. Caragana microphylla, C. liouana, and C. korshinskii are phylogenetically close but distribute vicariously in Mongolia plateau. To gain a better understanding of the ecological differentiation between these three species, we examined the leaf gas exchange, growth, water use efficiency, biomass accumulation and allocation by subjecting their seedlings to low and high drought treatments in a glasshouse. Increasing drought stress had a significant effect on many aspects of seedling performance in all species, but the physiology and growth varied with species in response to drought. C. korshinskii exhibited lower sensitivity of photosynthetic rate and growth, lower specific leaf area, higher biomass allocation to roots, higher levels of water use efficiency to drought compared with the other two species. Only minor interspecific differences in growth performances were observed between C. liouana and C. microphylla. These results indicated that faster seedling growth rate and more efficient water use of C. korshinskii should confer increased drought tolerance and facilitate its establishment in more severe drought regions relative to C. liouana and C. microphylla.

A survey of etiologic hypotheses among testicular cancer researchers.

Science.gov (United States)

Stang, A; Trabert, B; Rusner, C; Poole, C; Almstrup, K; Rajpert-De Meyts, E; McGlynn, K A

2015-01-01

Basic research results can provide new ideas and hypotheses to be examined in epidemiological studies. We conducted a survey among testicular cancer researchers on hypotheses concerning the etiology of this malignancy. All researchers on the mailing list of Copenhagen Testis Cancer Workshops and corresponding authors of PubMed-indexed articles identified by the search term 'testicular cancer' and published within 10 years (in total 2750 recipients) were invited to respond to an e-mail-based survey. Participants of the 8th Copenhagen Testis Cancer Workshop in May 2014 were subsequently asked to rate the plausibility of the suggested etiologic hypotheses on a scale of 1 (very implausible) to 10 (very plausible). This report describes the methodology of the survey, the score distributions by individual hypotheses, hypothesis group, and the participants' major research fields, and discuss the hypotheses that scored as most plausible. We also present plans for improving the survey that may be repeated at a next international meeting of experts in testicular cancer. Overall 52 of 99 (53%) registered participants of the 8th Copenhagen Testis Cancer Workshop submitted the plausibility rating form. Fourteen of 27 hypotheses were related to exposures during pregnancy. Hypotheses with the highest mean plausibility ratings were either related to pre-natal exposures or exposures that might have an effect during pregnancy and in post-natal life. The results of the survey may be helpful for triggering more specific etiologic hypotheses that include factors related to endocrine disruption, DNA damage, inflammation, and nutrition during pregnancy. The survey results may stimulate a multidisciplinary discussion about new etiologic hypotheses of testicular cancer. Published 2014. This article is a U. S. Government work and is in the public domain in the USA.

Testing competing hypotheses about single trial fMRI

DEFF Research Database (Denmark)

Hansen, Lars Kai; Purushotham, Archana; Kim, Seong-Ge

2002-01-01

We use a Bayesian framework to compute probabilities of competing hypotheses about functional activation based on single trial fMRI measurements. Within the framework we obtain a complete probabilistic picture of competing hypotheses, hence control of both type I and type II errors....

Scientific 'Laws', 'Hypotheses' and 'Theories'

Indian Academy of Sciences (India)

verified, the hypothesis changes from the status of a 'mere' hypothesis, and ... a pre-existing law and the body of facts upon which that law is based. Hypotheses .... implicit belief that order objectively exists in nature, and that scientific laws ...

Signatures of seaway closures and founder dispersal in the phylogeny of a circumglobally distributed seahorse lineage.

Science.gov (United States)

Teske, Peter R; Hamilton, Healy; Matthee, Conrad A; Barker, Nigel P

2007-08-15

The importance of vicariance events on the establishment of phylogeographic patterns in the marine environment is well documented, and generally accepted as an important cause of cladogenesis. Founder dispersal (i.e. long-distance dispersal followed by founder effect speciation) is also frequently invoked as a cause of genetic divergence among lineages, but its role has long been challenged by vicariance biogeographers. Founder dispersal is likely to be common in species that colonize remote habitats by means of rafting (e.g. seahorses), as long-distance dispersal events are likely to be rare and subsequent additional recruitment from the source habitat is unlikely. In the present study, the relative importance of vicariance and founder dispersal as causes of cladogenesis in a circumglobally distributed seahorse lineage was investigated using molecular dating. A phylogeny was reconstructed using sequence data from mitochondrial and nuclear markers, and the well-documented closure of the Central American seaway was used as a primary calibration point to test whether other bifurcations in the phylogeny could also have been the result of vicariance events. The feasibility of three other vicariance events was explored: a) the closure of the Indonesian Seaway, resulting in sister lineages associated with the Indian Ocean and West Pacific, respectively; b) the closure of the Tethyan Seaway, resulting in sister lineages associated with the Indo-Pacific and Atlantic Ocean, respectively, and c) continental break-up during the Mesozoic followed by spreading of the Atlantic Ocean, resulting in pairs of lineages with amphi-Atlantic distribution patterns. Comparisons of pairwise genetic distances among the seahorse species hypothesized to have diverged as a result of the closure of the Central American Seaway with those of published teleost sequences having the same distribution patterns show that the seahorses were among the last to diverge. This suggests that their

Signatures of seaway closures and founder dispersal in the phylogeny of a circumglobally distributed seahorse lineage

Directory of Open Access Journals (Sweden)

Matthee Conrad A

2007-08-01

Full Text Available Abstract Background The importance of vicariance events on the establishment of phylogeographic patterns in the marine environment is well documented, and generally accepted as an important cause of cladogenesis. Founder dispersal (i.e. long-distance dispersal followed by founder effect speciation is also frequently invoked as a cause of genetic divergence among lineages, but its role has long been challenged by vicariance biogeographers. Founder dispersal is likely to be common in species that colonize remote habitats by means of rafting (e.g. seahorses, as long-distance dispersal events are likely to be rare and subsequent additional recruitment from the source habitat is unlikely. In the present study, the relative importance of vicariance and founder dispersal as causes of cladogenesis in a circumglobally distributed seahorse lineage was investigated using molecular dating. A phylogeny was reconstructed using sequence data from mitochondrial and nuclear markers, and the well-documented closure of the Central American seaway was used as a primary calibration point to test whether other bifurcations in the phylogeny could also have been the result of vicariance events. The feasibility of three other vicariance events was explored: a the closure of the Indonesian Seaway, resulting in sister lineages associated with the Indian Ocean and West Pacific, respectively; b the closure of the Tethyan Seaway, resulting in sister lineages associated with the Indo-Pacific and Atlantic Ocean, respectively, and c continental break-up during the Mesozoic followed by spreading of the Atlantic Ocean, resulting in pairs of lineages with amphi-Atlantic distribution patterns. Results Comparisons of pairwise genetic distances among the seahorse species hypothesized to have diverged as a result of the closure of the Central American Seaway with those of published teleost sequences having the same distribution patterns show that the seahorses were among the last to

Hypotheses about geoglyphs at Nasca, Peru: new discoveries

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Jaroslav Klokočník

2016-07-01

Full Text Available The known hypotheses about the reasons why the geoglyphs in the Nasca and Palpa region of Peru were created are many: roads/paths, rituals/ceremonials, use of hallucinogens, astronomical meaning, influence of extraterrestrials, underground water… and so on. We present a new hypothesis, formulated by J. Sonnek (first published in 2011 in the context of all previous hypotheses.1 Sonnek explains the geoglyphs as tidied work areas for the production of rope and nets, although he goes much further than Stierlin. This eccentric hypothesis now has not only experimental but also archaeological and ethnographical support, which is presented here. Geoglyphs of a special shape were discovered in the pampas; they may represent technical objects – different types of ‘rope twisters’. Following this idea, Sonnek made technical devices (using today’s materials and tested them in practice; they work perfectly, see his YouTube videos.2 In November 2012, wooden pieces, which may be the remnants of ropemaking, were collected from the pampa near the towns of Nasca and Palpa, in vicinity of these hypothetic ropemaking places. Radiocarbon testing by 14C standardized radio-carbon age according to Stuiver-Polach convention and Accelerator Mass Spectroscopy (AMS of these wood pieces shows the age to be in a wide range from Early Nasca to the 17th century (and to our epoch with a fake geoglyph, too, thus supporting (but surely not proving the new hypothesis. Moreover, in the Quechua language, the word huasca, waskha (read: uasca means a rope or cord or place where these are produced. This word is very similar to ‘nasca’.

Scientific 'Laws', 'Hypotheses' and 'Theories'

Indian Academy of Sciences (India)

theories, defines a hypothesis as "any supposition which we may ... about the origin of the solar system are also hypotheses of this type. They are about the birth of the planets, an event, which has happened, in the past history of our Universe.

Scientific'Laws','Hypotheses' and'Theories'

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 12. Scientific 'Laws', 'Hypotheses' and 'Theories' - How are They Related? J R Lakshmana Rao. General Article Volume 3 Issue 12 December 1998 pp 55-61. Fulltext. Click here to view fulltext PDF. Permanent link:

Interplay between Hippocampal Sharp-Wave-Ripple Events and Vicarious Trial and Error Behaviors in Decision Making.

Science.gov (United States)

Papale, Andrew E; Zielinski, Mark C; Frank, Loren M; Jadhav, Shantanu P; Redish, A David

2016-12-07

Current theories posit that memories encoded during experiences are subsequently consolidated into longer-term storage. Hippocampal sharp-wave-ripple (SWR) events have been linked to this consolidation process during sleep, but SWRs also occur during awake immobility, where their role remains unclear. We report that awake SWR rates at the reward site are inversely related to the prevalence of vicarious trial and error (VTE) behaviors, thought to be involved in deliberation processes. SWR rates were diminished immediately after VTE behaviors and an increase in the rate of SWR events at the reward site predicted a decrease in subsequent VTE behaviors at the choice point. Furthermore, SWR disruptions increased VTE behaviors. These results suggest an inverse relationship between SWRs and VTE behaviors and suggest that awake SWRs and associated planning and memory consolidation mechanisms are engaged specifically in the context of higher levels of behavioral certainty. Copyright © 2016 Elsevier Inc. All rights reserved.

One-pot regioselective synthesis of nitrophenyloxazolinyl styrene oxides by the Darzens reaction of vicarious nucleophilic substitution-formed carbanions of 2-dichloromethyl-4,4-dimethyloxazoline.

Science.gov (United States)

Florio, Saverio; Lorusso, Patrizia; Granito, Catia; Luisi, Renzo; Troisi, Luigino

2004-07-23

The vicarious nucleophilic substitution reaction of dichloromethyloxazoline 2 with nitrobenzene has been investigated. Treatment of 2 with t-BuOK followed by the addition of nitrobenzene leads to benzylic carbanions 4 or 9 depending upon the solvent used (DMSO, DMF, or THF). Subsequent treatment of 4 or 9 with aldehydes, in a Darzens-like reaction, furnishes very good yields of nitrophenyl oxazolinyloxiranes 8 and 11. 1,2-Dioxazolinyl-1,2-dinitrophenylethene 7 forms quantitatively when carbanion 4 is allowed to warm to room temperature in the absence of external electrophiles.

Testing hypotheses for differences between linear regression lines

Science.gov (United States)

Stanley J. Zarnoch

2009-01-01

Five hypotheses are identified for testing differences between simple linear regression lines. The distinctions between these hypotheses are based on a priori assumptions and illustrated with full and reduced models. The contrast approach is presented as an easy and complete method for testing for overall differences between the regressions and for making pairwise...

Influence of previous knowledge in Torrance tests of creative thinking

OpenAIRE

Aranguren, María; Consejo Nacional de Investigaciones Científicas y Técnicas CONICET

2015-01-01

The aim of this work is to analyze the influence of study field, expertise and recreational activities participation in Torrance Tests of Creative Thinking (TTCT, 1974) performance. Several hypotheses were postulated to explore the possible effects of previous knowledge in TTCT verbal and TTCT figural university students’ outcomes. Participants in this study included 418 students from five study fields: Psychology;Philosophy and Literature, Music; Engineering; and Journalism and Advertisin...

Vicarious learning of children's social-anxiety-related fear beliefs and emotional Stroop bias.

Science.gov (United States)

Askew, Chris; Hagel, Anna; Morgan, Julie

2015-08-01

Models of social anxiety suggest that negative social experiences contribute to the development of social anxiety, and this is supported by self-report research. However, there is relatively little experimental evidence for the effects of learning experiences on social cognitions. The current study examined the effect of observing a social performance situation with a negative outcome on children's (8 to 11 years old) fear-related beliefs and cognitive processing. Two groups of children were each shown 1 of 2 animated films of a person trying to score in basketball while being observed by others; in 1 film, the outcome was negative, and in the other, it was neutral. Children's fear-related beliefs about performing in front of others were measured before and after the film and children were asked to complete an emotional Stroop task. Results showed that social fear beliefs increased for children who saw the negative social performance film. In addition, these children showed an emotional Stroop bias for social-anxiety-related words compared to children who saw the neutral film. The findings have implications for our understanding of social anxiety disorder and suggest that vicarious learning experiences in childhood may contribute to the development of social anxiety. (c) 2015 APA, all rights reserved).

Discovery of previously unidentified genomic disorders from the duplication architecture of the human genome

NARCIS (Netherlands)

Sharp, Andrew J.; Hansen, Sierra; Selzer, Rebecca R.; Cheng, Ze; Regan, Regina; Hurst, Jane A.; Stewart, Helen; Price, Sue M.; Blair, Edward; Hennekam, Raoul C.; Fitzpatrick, Carrie A.; Segraves, Rick; Richmond, Todd A.; Guiver, Cheryl; Albertson, Donna G.; Pinkel, Daniel; Eis, Peggy S.; Schwartz, Stuart; Knight, Samantha J. L.; Eichler, Evan E.

2006-01-01

Genomic disorders are characterized by the presence of flanking segmental duplications that predispose these regions to recurrent rearrangement. Based on the duplication architecture of the genome, we investigated 130 regions that we hypothesized as candidates for previously undescribed genomic

Middle School Students' Science Self-Efficacy and Its Sources: Examination of Gender Difference

Science.gov (United States)

Kiran, Dekant; Sungur, Semra

2012-01-01

The main purpose of the present study is to investigate middle school students' science self-efficacy as well as its sources and outcomes as a function of gender. Bandura's hypothesized sources of self-efficacy (i.e., mastery experience, vicarious experience, verbal persuasion, and emotional arousal) in addition to being inviting with self and…

Left Prefrontal Activity Reflects the Ability of Vicarious Fear Learning: A Functional Near-Infrared Spectroscopy Study

Directory of Open Access Journals (Sweden)

Qingguo Ma

2013-01-01

Full Text Available Fear could be acquired indirectly via social observation. However, it remains unclear which cortical substrate activities are involved in vicarious fear transmission. The present study was to examine empathy-related processes during fear learning by-proxy and to examine the activation of prefrontal cortex by using functional near-infrared spectroscopy. We simultaneously measured participants’ hemodynamic responses and skin conductance responses when they were exposed to a movie. In this movie, a demonstrator (i.e., another human being was receiving a classical fear conditioning. A neutral colored square paired with shocks (CSshock and another colored square paired with no shocks (CSno-shock were randomly presented in front of the demonstrator. Results showed that increased concentration of oxygenated hemoglobin in left prefrontal cortex was observed when participants watched a demonstrator seeing CSshock compared with that exposed to CSno-shock. In addition, enhanced skin conductance responses showing a demonstrator's aversive experience during learning object-fear association were observed. The present study suggests that left prefrontal cortex, which may reflect speculation of others’ mental state, is associated with social fear transmission.

Left prefrontal activity reflects the ability of vicarious fear learning: a functional near-infrared spectroscopy study.

Science.gov (United States)

Ma, Qingguo; Huang, Yujing; Wang, Lei

2013-01-01

Fear could be acquired indirectly via social observation. However, it remains unclear which cortical substrate activities are involved in vicarious fear transmission. The present study was to examine empathy-related processes during fear learning by-proxy and to examine the activation of prefrontal cortex by using functional near-infrared spectroscopy. We simultaneously measured participants' hemodynamic responses and skin conductance responses when they were exposed to a movie. In this movie, a demonstrator (i.e., another human being) was receiving a classical fear conditioning. A neutral colored square paired with shocks (CS(shock)) and another colored square paired with no shocks (CS(no-shock)) were randomly presented in front of the demonstrator. Results showed that increased concentration of oxygenated hemoglobin in left prefrontal cortex was observed when participants watched a demonstrator seeing CS(shock) compared with that exposed to CS(no-shock). In addition, enhanced skin conductance responses showing a demonstrator's aversive experience during learning object-fear association were observed. The present study suggests that left prefrontal cortex, which may reflect speculation of others' mental state, is associated with social fear transmission.

New hypotheses regarding the Danish health puzzle.

Science.gov (United States)

Bakah, May; Raphael, Dennis

2017-12-01

Nordic welfare states have achieved admirable population health profiles as a result of public policies that provide economic and social security across the life course. Denmark has been an exception to this rule, as its life expectancies and infant mortality rates since the mid-1970s have lagged behind the other Nordic nations and, in the case of life expectancy, behind most Organisation for Economic Co-operation and Development nations. In this review paper, we identify a number of new hypotheses for why this may be the case. These hypotheses concern the health effects of neo-liberal restructuring of the economy and its institutions, the institution of flexi-security in Denmark's labour market and the influence of Denmark's tobacco and alcohol industries. Also of note is that Denmark experienced higher unemployment rates during its initial period of health stagnation, as well as its treatment of non-Western immigrants and high wealth inequality and, until recently, the fact that Denmark did not systematically address the issue of health inequalities. These hypotheses may serve as covering explanations for the usually provided accounts of elevated behavioural risks and psychosocial stress as being responsible for Denmark's health profile.

Phylogeography of a widespread species: pre-glacial vicariance, refugia, occasional blocking straits and long-distance migrations.

Science.gov (United States)

Santiso, Xabier; Lopez, Lúa; Retuerto, Rubén; Barreiro, Rodolfo

2016-01-13

Phylogeographic studies give us the opportunity to reconstruct the historical migrations of species and link them with climatic and geographic variation. They are, therefore, a key tool to understanding the relationships among biology, geology and history. One of the most interesting biogeographical areas of the world is the Mediterranean region. However, in this area, the description of concordant phylogeographic patterns is quite scarce, which limits the understanding of evolutionary patterns related to climate. Species with one-dimensional distribution ranges, such as the strawberry tree (Arbutus unedo), are particularly useful to unravel these patterns. Here, we describe its phylogeographic structure and check for concordance with patterns seen in other Mediterranean plants: longitudinal/latitudinal clines of diversity, evidence for glacial refugia and the role of sea straits in dispersal. We also identify the most likely source for the disjunct Irish population. With this aim, we sequenced four chloroplast non-coding fragments of A. unedo from 23 populations covering its whole distribution. We determined the genetic diversity, population structure, haplotype genealogy and time to the most recent common ancestor. The genealogy revealed two clades that separated during the last 700 ky but before the last glacial maximum. One clade occupies Atlantic Iberia and North Africa, while the other occurs in the Western Mediterranean. The Eastern Mediterranean is inhabited by newer haplotypes derived from both clades, while the Irish population is closely related to Iberian demes. The straits of Sicily and Gibraltar partially restricted the gene flow. We concluded that a vicariance event during the Late Quaternary in the western end of the species' range followed by eastward migration seems a likely explanation for the observed phylogeographic pattern. The role of straits indicates an occasional communication between Europe and North Africa, suggesting that the latter was

The revelation effect: A meta-analytic test of hypotheses.

Science.gov (United States)

Aßfalg, André; Bernstein, Daniel M; Hockley, William

2017-12-01

Judgments can depend on the activity directly preceding them. An example is the revelation effect whereby participants are more likely to claim that a stimulus is familiar after a preceding task, such as solving an anagram, than without a preceding task. We test conflicting predictions of four revelation-effect hypotheses in a meta-analysis of 26 years of revelation-effect research. The hypotheses' predictions refer to three subject areas: (1) the basis of judgments that are subject to the revelation effect (recollection vs. familiarity vs. fluency), (2) the degree of similarity between the task and test item, and (3) the difficulty of the preceding task. We use a hierarchical multivariate meta-analysis to account for dependent effect sizes and variance in experimental procedures. We test the revelation-effect hypotheses with a model selection procedure, where each model corresponds to a prediction of a revelation-effect hypothesis. We further quantify the amount of evidence for one model compared to another with Bayes factors. The results of this analysis suggest that none of the extant revelation-effect hypotheses can fully account for the data. The general vagueness of revelation-effect hypotheses and the scarcity of data were the major limiting factors in our analyses, emphasizing the need for formalized theories and further research into the puzzling revelation effect.

Intelligence, previous convictions and interrogative suggestibility: a path analysis of alleged false-confession cases.

Science.gov (United States)

Sharrock, R; Gudjonsson, G H

1993-05-01

The main purpose of this study was to investigate the relationship between interrogative suggestibility and previous convictions among 108 defendants in criminal trials, using a path analysis technique. It was hypothesized that previous convictions, which may provide defendants with interrogative experiences, would correlate negatively with 'shift' as measured by the Gudjonsson Suggestibility Scale (Gudjonsson, 1984a), after intelligence and memory had been controlled for. The hypothesis was partially confirmed and the theoretical and practical implications of the findings are discussed.

Singularity hypotheses a scientific and philosophical assessment

CERN Document Server

Moor, James; Søraker, Johnny; Steinhart, Eric

2012-01-01

Singularity Hypotheses: A Scientific and Philosophical Assessment offers authoritative, jargon-free essays and critical commentaries on accelerating technological progress and the notion of technological singularity. It focuses on conjectures about the intelligence explosion, transhumanism, and whole brain emulation. Recent years have seen a plethora of forecasts about the profound, disruptive impact that is likely to result from further progress in these areas. Many commentators however doubt the scientific rigor of these forecasts, rejecting them as speculative and unfounded. We therefore invited prominent computer scientists, physicists, philosophers, biologists, economists and other thinkers to assess the singularity hypotheses. Their contributions go beyond speculation, providing deep insights into the main issues and a balanced picture of the debate.

COVAR: Computer Program for Multifactor Relative Risks and Tests of Hypotheses Using a Variance-Covariance Matrix from Linear and Log-Linear Regression

Directory of Open Access Journals (Sweden)

Leif E. Peterson

1997-11-01

Full Text Available A computer program for multifactor relative risks, confidence limits, and tests of hypotheses using regression coefficients and a variance-covariance matrix obtained from a previous additive or multiplicative regression analysis is described in detail. Data used by the program can be stored and input from an external disk-file or entered via the keyboard. The output contains a list of the input data, point estimates of single or joint effects, confidence intervals and tests of hypotheses based on a minimum modified chi-square statistic. Availability of the program is also discussed.

Vicarious social defeat stress: Bridging the gap between physical and emotional stress.

Science.gov (United States)

Sial, Omar K; Warren, Brandon L; Alcantara, Lyonna F; Parise, Eric M; Bolaños-Guzmán, Carlos A

2016-01-30

Animal models capable of differentiating the neurobiological intricacies between physical and emotional stress are scarce. Current models rely primarily on physical stressors (e.g., chronic unpredictable or mild stress, social defeat, learned helplessness), and neglect the impact of psychological stress alone. This is surprising given extensive evidence that a traumatic event needs not be directly experienced to produce enduring perturbations on an individual's health and psychological well-being. Post-traumatic stress disorder (PTSD), a highly debilitating neuropsychiatric disorder characterized by intense fear of trauma-related stimuli, often occurs in individuals that have only witnessed a traumatic event. By modifying the chronic social defeat stress (CSDS) paradigm to include a witness component (witnessing the social defeat of another mouse), we demonstrate a novel behavioral paradigm capable of inducing a robust behavioral syndrome reminiscent of PTSD in emotionally stressed adult mice. We describe the vicarious social defeat stress (VSDS) model that is capable of inducing a host of behavioral deficits that include social avoidance and other depressive- and anxiety-like phenotypes in adult male mice. VSDS exposure induces weight loss and spike in serum corticosterone (CORT) levels. A month after stress, these mice retain the social avoidant phenotype and have an increased CORT response when exposed to subsequent stress. The VSDS is a novel paradigm capable of inducing emotional stress by isolating physical stress/confrontation in mice. The VSDS model can be used to study the short- and long-term neurobiological consequences of exposure to emotional stress in mice. Copyright © 2015 Elsevier B.V. All rights reserved.

Supervised Vicarious Calibration (SVC of Multi-Source Hyperspectral Remote-Sensing Data

Directory of Open Access Journals (Sweden)

Anna Brook

2015-05-01

Full Text Available Introduced in 2011, the supervised vicarious calibration (SVC approach is a promising approach to radiometric calibration and atmospheric correction of airborne hyperspectral (HRS data. This paper presents a comprehensive study by which the SVC method has been systematically examined and a complete protocol for its practical execution has been established—along with possible limitations encountered during the campaign. The technique was applied to multi-sourced HRS data in order to: (1 verify the at-sensor radiometric calibration and (2 obtain radiometric and atmospheric correction coefficients. Spanning two select study sites along the southeast coast of France, data were collected simultaneously by three airborne sensors (AisaDUAL, AHS and CASI-1500i aboard two aircrafts (CASA of National Institute for Aerospace Technology INTA ES and DORNIER 228 of NERC-ARSF Centre UK. The SVC ground calibration site was assembled along sand dunes near Montpellier and the thematic data were acquired from other areas in the south of France (Salon-de-Provence, Marseille, Avignon and Montpellier on 28 October 2010 between 12:00 and 16:00 UTC. The results of this study confirm that the SVC method enables reliable inspection and, if necessary, in-situ fine radiometric recalibration of airborne hyperspectral data. Independent of sensor or platform quality, the SVC approach allows users to improve at-sensor data to obtain more accurate physical units and subsequently improved reflectance information. Flight direction was found to be important, whereas the flight altitude posed very low impact. The numerous rules and major outcomes of this experiment enable a new standard of atmospherically corrected data based on better radiometric output. Future research should examine the potential of SVC to be applied to super-and-hyperspectral data obtained from on-orbit sensors.

Phylogenetic paleobiogeography of Late Ordovician Laurentian brachiopods

Directory of Open Access Journals (Sweden)

Jennifer E. Bauer

2014-12-01

Full Text Available Phylogenetic biogeographic analysis of four brachiopod genera was used to uncover large-scale geologic drivers of Late Ordovician biogeographic differentiation in Laurentia. Previously generated phylogenetic hypotheses were converted into area cladograms, ancestral geographic ranges were optimized and speciation events characterized as via dispersal or vicariance, when possible. Area relationships were reconstructed using Lieberman-modified Brooks Parsimony Analysis. The resulting area cladograms indicate tectonic and oceanographic changes were the primary geologic drivers of biogeographic patterns within the focal taxa. The Taconic tectophase contributed to the separation of the Appalachian and Central basins as well as the two midcontinent basins, whereas sea level rise following the Boda Event promoted interbasinal dispersal. Three migration pathways into the Cincinnati Basin were recognized, which supports the multiple pathway hypothesis for the Richmondian Invasion.

Testing statistical hypotheses

CERN Document Server

Lehmann, E L

2005-01-01

The third edition of Testing Statistical Hypotheses updates and expands upon the classic graduate text, emphasizing optimality theory for hypothesis testing and confidence sets. The principal additions include a rigorous treatment of large sample optimality, together with the requisite tools. In addition, an introduction to the theory of resampling methods such as the bootstrap is developed. The sections on multiple testing and goodness of fit testing are expanded. The text is suitable for Ph.D. students in statistics and includes over 300 new problems out of a total of more than 760. E.L. Lehmann is Professor of Statistics Emeritus at the University of California, Berkeley. He is a member of the National Academy of Sciences and the American Academy of Arts and Sciences, and the recipient of honorary degrees from the University of Leiden, The Netherlands and the University of Chicago. He is the author of Elements of Large-Sample Theory and (with George Casella) he is also the author of Theory of Point Estimat...

Conflict between place and response navigation strategies: effects on vicarious trial and error (VTE) behaviors.

Science.gov (United States)

Schmidt, Brandy; Papale, Andrew; Redish, A David; Markus, Etan J

2013-02-15

Navigation can be accomplished through multiple decision-making strategies, using different information-processing computations. A well-studied dichotomy in these decision-making strategies compares hippocampal-dependent "place" and dorsal-lateral striatal-dependent "response" strategies. A place strategy depends on the ability to flexibly respond to environmental cues, while a response strategy depends on the ability to quickly recognize and react to situations with well-learned action-outcome relationships. When rats reach decision points, they sometimes pause and orient toward the potential routes of travel, a process termed vicarious trial and error (VTE). VTE co-occurs with neurophysiological information processing, including sweeps of representation ahead of the animal in the hippocampus and transient representations of reward in the ventral striatum and orbitofrontal cortex. To examine the relationship between VTE and the place/response strategy dichotomy, we analyzed data in which rats were cued to switch between place and response strategies on a plus maze. The configuration of the maze allowed for place and response strategies to work competitively or cooperatively. Animals showed increased VTE on trials entailing competition between navigational systems, linking VTE with deliberative decision-making. Even in a well-learned task, VTE was preferentially exhibited when a spatial selection was required, further linking VTE behavior with decision-making associated with hippocampal processing.

Cancer risks near nuclear facilities: the importance of research design and explicit study hypotheses.

Science.gov (United States)

Wing, Steve; Richardson, David B; Hoffmann, Wolfgang

2011-04-01

In April 2010, the U.S. Nuclear Regulatory Commission asked the National Academy of Sciences to update a 1990 study of cancer risks near nuclear facilities. Prior research on this topic has suffered from problems in hypothesis formulation and research design. We review epidemiologic principles used in studies of generic exposure-response associations and in studies of specific sources of exposure. We then describe logical problems with assumptions, formation of testable hypotheses, and interpretation of evidence in previous research on cancer risks near nuclear facilities. Advancement of knowledge about cancer risks near nuclear facilities depends on testing specific hypotheses grounded in physical and biological mechanisms of exposure and susceptibility while considering sample size and ability to adequately quantify exposure, ascertain cancer cases, and evaluate plausible confounders. Next steps in advancing knowledge about cancer risks near nuclear facilities require studies of childhood cancer incidence, focus on in utero and early childhood exposures, use of specific geographic information, and consideration of pathways for transport and uptake of radionuclides. Studies of cancer mortality among adults, cancers with long latencies, large geographic zones, and populations that reside at large distances from nuclear facilities are better suited for public relations than for scientific purposes.

Testing statistical hypotheses of equivalence

CERN Document Server

Wellek, Stefan

2010-01-01

Equivalence testing has grown significantly in importance over the last two decades, especially as its relevance to a variety of applications has become understood. Yet published work on the general methodology remains scattered in specialists' journals, and for the most part, it focuses on the relatively narrow topic of bioequivalence assessment.With a far broader perspective, Testing Statistical Hypotheses of Equivalence provides the first comprehensive treatment of statistical equivalence testing. The author addresses a spectrum of specific, two-sided equivalence testing problems, from the

Mirror bootstrap method for testing hypotheses of one mean

OpenAIRE

Varvak, Anna

2012-01-01

The general philosophy for bootstrap or permutation methods for testing hypotheses is to simulate the variation of the test statistic by generating the sampling distribution which assumes both that the null hypothesis is true, and that the data in the sample is somehow representative of the population. This philosophy is inapplicable for testing hypotheses for a single parameter like the population mean, since the two assumptions are contradictory (e.g., how can we assume both that the mean o...

The human factor: behavioral and neural correlates of humanized perception in moral decision making.

Science.gov (United States)

Majdandžić, Jasminka; Bauer, Herbert; Windischberger, Christian; Moser, Ewald; Engl, Elisabeth; Lamm, Claus

2012-01-01

The extent to which people regard others as full-blown individuals with mental states ("humanization") seems crucial for their prosocial motivation towards them. Previous research has shown that decisions about moral dilemmas in which one person can be sacrificed to save multiple others do not consistently follow utilitarian principles. We hypothesized that this behavior can be explained by the potential victim's perceived humanness and an ensuing increase in vicarious emotions and emotional conflict during decision making. Using fMRI, we assessed neural activity underlying moral decisions that affected fictitious persons that had or had not been experimentally humanized. In implicit priming trials, participants either engaged in mentalizing about these persons (Humanized condition) or not (Neutral condition). In subsequent moral dilemmas, participants had to decide about sacrificing these persons' lives in order to save the lives of numerous others. Humanized persons were sacrificed less often, and the activation pattern during decisions about them indicated increased negative affect, emotional conflict, vicarious emotions, and behavioral control (pgACC/mOFC, anterior insula/IFG, aMCC and precuneus/PCC). Besides, we found enhanced effective connectivity between aMCC and anterior insula, which suggests increased emotion regulation during decisions affecting humanized victims. These findings highlight the importance of others' perceived humanness for prosocial behavior - with aversive affect and other-related concern when imagining harming more "human-like" persons acting against purely utilitarian decisions.

The human factor: behavioral and neural correlates of humanized perception in moral decision making.

Directory of Open Access Journals (Sweden)

Jasminka Majdandžić

Full Text Available The extent to which people regard others as full-blown individuals with mental states ("humanization" seems crucial for their prosocial motivation towards them. Previous research has shown that decisions about moral dilemmas in which one person can be sacrificed to save multiple others do not consistently follow utilitarian principles. We hypothesized that this behavior can be explained by the potential victim's perceived humanness and an ensuing increase in vicarious emotions and emotional conflict during decision making. Using fMRI, we assessed neural activity underlying moral decisions that affected fictitious persons that had or had not been experimentally humanized. In implicit priming trials, participants either engaged in mentalizing about these persons (Humanized condition or not (Neutral condition. In subsequent moral dilemmas, participants had to decide about sacrificing these persons' lives in order to save the lives of numerous others. Humanized persons were sacrificed less often, and the activation pattern during decisions about them indicated increased negative affect, emotional conflict, vicarious emotions, and behavioral control (pgACC/mOFC, anterior insula/IFG, aMCC and precuneus/PCC. Besides, we found enhanced effective connectivity between aMCC and anterior insula, which suggests increased emotion regulation during decisions affecting humanized victims. These findings highlight the importance of others' perceived humanness for prosocial behavior - with aversive affect and other-related concern when imagining harming more "human-like" persons acting against purely utilitarian decisions.

Preliminary testing of flow-ecology hypotheses developed for the GCP LCC region

Science.gov (United States)

Brewer, Shannon K.; Davis, Mary

2014-01-01

The Ecological Limits of Hydrological Alteration (ELOHA) framework calls for the development of flow-ecology hypotheses to support protection of the flow regime from ecologically harmful alteration due to human activities. As part of a larger instream flow project for the Gulf Coast Prairie Landscape Conservation Cooperative (GCP LCC), regional flow-ecology hypotheses were developed for fish, mussels, birds, and riparian vegetation (Davis and Brewer 20141). The objective of this study was to assess the usefulness of existing ecological and hydrological data to test these hypotheses or others that may be developed in the future. Several databases related to biological collections and hydrologic data from Oklahoma, Texas, and Louisiana were compiled. State fish-community data from Oklahoma and Louisiana were summarized and paired with existing USGS gage data having at least a 40-year period of record that could be separated into reference and current conditions for comparison. The objective of this study was not to conduct exhaustive analyses of these data, the hypotheses, or analyses interpretation, but rather to use these data to determine if existing data were adequate to statistically test the regional flow-ecology hypotheses. The regional flow-ecology hypotheses were developed for the GCP LCC by a committee chaired by Shannon Brewer and Mary Davis (Davis and Brewer 2014). Existing data were useful for informing the hypotheses and suggest support for some hypotheses, but also highlight the need for additional testing and development as some results contradicted hypotheses. Results presented here suggest existing data are adequate to support some flow-ecology hypotheses; however, lack of sampling effort reported with the fish collections and the need for ecoregion-specific analyses suggest more data would be beneficial to analyses in some ecoregions. Additional fish sampling data from Texas and Louisiana will be available for future analyses and may ameliorate

Evaluation of Extremal Hypotheses as a Criterion to Resolve Channel Indeterminacy

Science.gov (United States)

Tranmer, A.

2012-12-01

Design criteria for river restoration and sustainable development have significantly advanced in recent decades, yet complete deterministic formulations to address channel form and sinuosity still prove elusive. Many hypotheses have been presented to ascertain the dynamic-equilibrium of a stream at both the cross sectional and reach level. These efforts to better understand the functioning of alluvial systems include regime theory, stability theory, perturbation analysis, threshold theory, reference reach comparison, downstream hydraulic geometry, and extremal hypotheses. The latter of these theories, the extremal hypothesis, is based on optimizing one variable or criterion in the alluvial system in order to find closure to the channel design problem. Currently, there is no method to directly compare the various hypotheses at the system scale, understanding of their sensitivity to the various formulae employed or consensus regarding which hypothesis is most appropriate. This study analyzed the various extremal hypotheses in as close to a pristine environment as exists (a remote part of Patagonia, Chile), in order to assess which hypothesis (or collective hypotheses) is most appropriate for channel design. Extremal hypotheses were applied in the longitudinal direction, under the assumption of a space-for-time substitution, to evaluate the geomorphic trends of a river evolving during deglaciation. The space-for-time model assumes the watershed reaches stable, dynamic-equilibrium in its lower meandering reaches and the point of equilibrium extends upstream through its braiding reaches as the watershed adapts to new climatic and environmental conditions. Extremal hypotheses applied in a downstream fashion are then expected to predict chaotic and oversized channel characteristics in the upstream reaches and trend towards a point of equilibrium (minimum/maximum of tested hypothesis). Initial findings indicate that many hypotheses predict similar geometry and sinuosity

Testing Hypotheses on Risk Factors for Scientific Misconduct via Matched-Control Analysis of Papers Containing Problematic Image Duplications.

Science.gov (United States)

Fanelli, Daniele; Costas, Rodrigo; Fang, Ferric C; Casadevall, Arturo; Bik, Elisabeth M

2018-02-19

It is commonly hypothesized that scientists are more likely to engage in data falsification and fabrication when they are subject to pressures to publish, when they are not restrained by forms of social control, when they work in countries lacking policies to tackle scientific misconduct, and when they are male. Evidence to test these hypotheses, however, is inconclusive due to the difficulties of obtaining unbiased data. Here we report a pre-registered test of these four hypotheses, conducted on papers that were identified in a previous study as containing problematic image duplications through a systematic screening of the journal PLoS ONE. Image duplications were classified into three categories based on their complexity, with category 1 being most likely to reflect unintentional error and category 3 being most likely to reflect intentional fabrication. We tested multiple parameters connected to the hypotheses above with a matched-control paradigm, by collecting two controls for each paper containing duplications. Category 1 duplications were mostly not associated with any of the parameters tested, as was predicted based on the assumption that these duplications were mostly not due to misconduct. Categories 2 and 3, however, exhibited numerous statistically significant associations. Results of univariable and multivariable analyses support the hypotheses that academic culture, peer control, cash-based publication incentives and national misconduct policies might affect scientific integrity. No clear support was found for the "pressures to publish" hypothesis. Female authors were found to be equally likely to publish duplicated images compared to males. Country-level parameters generally exhibited stronger effects than individual-level parameters, because developing countries were significantly more likely to produce problematic image duplications. This suggests that promoting good research practices in all countries should be a priority for the international

Comments and hypotheses on the mechanism of methane against ischemia/reperfusion injury

Directory of Open Access Journals (Sweden)

He Li

2017-01-01

Full Text Available As we all know, methane is a kind of fuel. Previous studies have shown that methanogens in the colon can react with carbon dioxide and hydrogen to produce methane. In a recent study, the anti-inflammatory effects of methane were shown in a dog model of small intestinal ischemia/reperfusion. The mechanism of this anti-inflammatory effect needs further investigation. Recently, studies have shown anti-inflammatory, anti-apoptotic and anti-oxidative effects of methane on different organic injuries. According to the results of these studies, we hypothesize that the initial effects of methane are to react with free radicals and enhance expression of antioxidase through forkhead box transcription factor class O pathway. The anti-inflammatory effect is following the anti-oxidative effect, and the anti-apoptotic effect relies on anti-inflammatory and anti-oxidative effects.

Evaluating hypotheses in geolocation on a very large sample of Twitter

DEFF Research Database (Denmark)

Salehi, Bahar; Søgaard, Anders

2017-01-01

Recent work in geolocation has madeseveral hypotheses about what linguisticmarkers are relevant to detect where peoplewrite from. In this paper, we examinesix hypotheses against a corpus consistingof all geo-tagged tweets from theUS, or whose geo-tags could be inferred,in a 19% sample of Twitter...

Noradrenergic signaling in the medial prefrontal cortex and amygdala differentially regulates vicarious trial-and-error in a spatial decision-making task.

Science.gov (United States)

Amemiya, Seiichiro; Kubota, Natsuko; Umeyama, Nao; Nishijima, Takeshi; Kita, Ichiro

2016-01-15

In uncertain choice situations, we deliberately search and evaluate possible options before taking an action. Once we form a preference regarding the current situation, we take an action more automatically and with less deliberation. In rats, the deliberation process can be seen in vicarious trial-and-error behavior (VTE), which is a head-orienting behavior toward options at a choice point. Recent neurophysiological findings suggest that VTE reflects the rat's thinking about future options as deliberation, expectation, and planning when rats feel conflict. VTE occurs depending on the demand: an increase occurs during initial learning, and a decrease occurs with progression in learning. However, the brain circuit underlying the regulation of VTE has not been thoroughly examined. In situations in which VTE often appears, the medial prefrontal cortex (mPFC) and the amygdala (AMY) are crucial for learning and decision making. Our previous study reported that noradrenaline regulates VTE. Here, to investigate whether the mPFC and AMY are involved in regulation of VTE, we examined the effects of local injection of clonidine, an alpha2 adrenergic autoreceptor agonist, into either region in rats during VTE and choice behavior during a T-maze choice task. Injection of clonidine into either region impaired selection of the advantageous choice in the task. Furthermore, clonidine injection into the mPFC suppressed occurrence of VTE in the early phase of the task, whereas injection into the AMY inhibited the decrease in VTE in the later phase and thus maintained a high level of VTE throughout the task. These results suggest that the mPFC and AMY play a role in the increase and decrease in VTE, respectively, and that noradrenergic mechanisms mediate the dynamic regulation of VTE over experiences. Copyright © 2015 Elsevier B.V. All rights reserved.

Causes of bat fatalities at wind turbines: Hypotheses and predictions

Science.gov (United States)

Cryan, P.M.; Barclay, R.M.R.

2009-01-01

Thousands of industrial-scale wind turbines are being built across the world each year to meet the growing demand for sustainable energy. Bats of certain species are dying at wind turbines in unprecedented numbers. Species of bats consistently affected by turbines tend to be those that rely on trees as roosts and most migrate long distances. Although considerable progress has been made in recent years toward better understanding the problem, the causes of bat fatalities at turbines remain unclear. In this synthesis, we review hypothesized causes of bat fatalities at turbines. Hypotheses of cause fall into 2 general categoriesproximate and ultimate. Proximate causes explain the direct means by which bats die at turbines and include collision with towers and rotating blades, and barotrauma. Ultimate causes explain why bats come close to turbines and include 3 general types: random collisions, coincidental collisions, and collisions that result from attraction of bats to turbines. The random collision hypothesis posits that interactions between bats and turbines are random events and that fatalities are representative of the bats present at a site. Coincidental hypotheses posit that certain aspects of bat distribution or behavior put them at risk of collision and include aggregation during migration and seasonal increases in flight activity associated with feeding or mating. A surprising number of attraction hypotheses suggest that bats might be attracted to turbines out of curiosity, misperception, or as potential feeding, roosting, flocking, and mating opportunities. Identifying, prioritizing, and testing hypothesized causes of bat collisions with wind turbines are vital steps toward developing practical solutions to the problem. ?? 2009 American Society of Mammalogists.

Adaptive hatching hypotheses do not explain asynchronous ...

African Journals Online (AJOL)

At the core of the suite of adaptive hatching hypotheses advanced to explain asynchronous hatching in birds is the assumption that if food is not limited then all the hatchlings will develop normally to adulthood. In this study Brown-headed Parrot Poicephalus cryptoxanthus chicks were hand fed and weighed on a daily basis.

A toothed turtle from the Late Jurassic of China and the global biogeographic history of turtles.

Science.gov (United States)

Joyce, Walter G; Rabi, Márton; Clark, James M; Xu, Xing

2016-10-28

Turtles (Testudinata) are a successful lineage of vertebrates with about 350 extant species that inhabit all major oceans and landmasses with tropical to temperate climates. The rich fossil record of turtles documents the adaptation of various sub-lineages to a broad range of habitat preferences, but a synthetic biogeographic model is still lacking for the group. We herein describe a new species of fossil turtle from the Late Jurassic of Xinjiang, China, Sichuanchelys palatodentata sp. nov., that is highly unusual by plesiomorphically exhibiting palatal teeth. Phylogenetic analysis places the Late Jurassic Sichuanchelys palatodentata in a clade with the Late Cretaceous Mongolochelys efremovi outside crown group Testudines thereby establishing the prolonged presence of a previously unrecognized clade of turtles in Asia, herein named Sichuanchelyidae. In contrast to previous hypotheses, M. efremovi and Kallokibotion bajazidi are not found within Meiolaniformes, a clade that is here reinterpreted as being restricted to Gondwana. A revision of the global distribution of fossil and recent turtle reveals that the three primary lineages of derived, aquatic turtles, including the crown, Paracryptodira, Pan-Pleurodira, and Pan-Cryptodira can be traced back to the Middle Jurassic of Euramerica, Gondwana, and Asia, respectively, which resulted from the primary break up of Pangaea at that time. The two primary lineages of Pleurodira, Pan-Pelomedusoides and Pan-Chelidae, can similarly be traced back to the Cretaceous of northern and southern Gondwana, respectively, which were separated from one another by a large desert zone during that time. The primary divergence of crown turtles was therefore driven by vicariance to the primary freshwater aquatic habitat of these lineages. The temporally persistent lineages of basal turtles, Helochelydridae, Meiolaniformes, Sichuanchelyidae, can similarly be traced back to the Late Mesozoic of Euramerica, southern Gondwana, and Asia. Given

Cancer stem cell hypotheses: Impact on modern molecular

Indian Academy of Sciences (India)

basis for the so-called cancer stem cell (CSC) hypotheses. The first exact proof of CSC ... or less equal ability for tumour regeneration and repopulation. (Nowell 1976 .... Also, there are reports that the 'stemness' (stem-like properties) of brain.

A novel approach to generating CER hypotheses based on mining clinical data.

Science.gov (United States)

Zhang, Shuo; Li, Lin; Yu, Yiqin; Sun, Xingzhi; Xu, Linhao; Zhao, Wei; Teng, Xiaofei; Pan, Yue

2013-01-01

Comparative effectiveness research (CER) is a scientific method of investigating the effectiveness of alternative intervention methods. In a CER study, clinical researchers typically start with a CER hypothesis, and aim to evaluate it by applying a series of medical statistical methods. Traditionally, the CER hypotheses are defined manually by clinical researchers. This makes the task of hypothesis generation very time-consuming and the quality of hypothesis heavily dependent on the researchers' skills. Recently, with more electronic medical data being collected, it is highly promising to apply the computerized method for discovering CER hypotheses from clinical data sets. In this poster, we proposes a novel approach to automatically generating CER hypotheses based on mining clinical data, and presents a case study showing that the approach can facilitate clinical researchers to identify potentially valuable hypotheses and eventually define high quality CER studies.

Development of a patient-reported outcome measure of recovery after abdominal surgery: a hypothesized conceptual framework.

Science.gov (United States)

Alam, Roshni; Figueiredo, Sabrina M; Balvardi, Saba; Nauche, Bénédicte; Landry, Tara; Lee, Lawrence; Mayo, Nancy E; Feldman, Liane S; Fiore, Julio F

2018-05-17

We initiated a research program to develop a novel patient-reported outcome measure (PROM) to assess postoperative recovery from the perspective of abdominal surgery patients. In light of FDA recommendations, the first stage of our program aimed to, based on previous literature and expert input, develop a hypothesized conceptual framework portraying the health domains that are potentially relevant to the process of recovery after abdominal surgery. This study was conducted in three phases: (1) systematic review to identify PROMs with measurement properties appraised in the context of recovery after abdominal surgery, (2) content analysis to categorize the health domains covered by the PROMs according to the ICF, and (3) two-round Delphi study to gain expert input regarding which of these health domains are relevant to the process of recovery. Participants were experts in perioperative care identified through two major surgical societies (35 invited). The systematic review identified 19 PROMs covering 66 ICF domains. 23 experts (66%) participated in the Delphi process. After Round 2, experts agreed that 22 health domains (8 body functions, 14 activities and participation) are potentially relevant to the process of recovery after abdominal surgery. These domains were organized into a diagram, representing our hypothesized conceptual framework. This hypothesized conceptual framework is an important first step in our research program and will be further refined based on in-depth qualitative interviews with patients. The sound methodological approach used to derive this framework may be valuable for studies aimed to develop PROMs according to FDA standards.

Individual differences in the impact of vicarious racism: African American students react to the George Zimmerman trial.

Science.gov (United States)

Mason, Tyler B; Maduro, Ralitsa S; Derlega, Valerian J; Hacker, Desi S; Winstead, Barbara A; Haywood, Jacqueline E

2017-04-01

This research focused on how race-based rejection sensitivity (RS-Race) and components of racial identity intensify negative psychological reactions to an incident of vicarious racism. We examined how these individual difference variables directly and/or indirectly predicted African American students' reactions to the trial of George Zimmerman in the killing of the African American teenager, Trayvon Martin. In Study 1, 471 African American students completed measures of RS-Race, thought intrusions about the Zimmerman trial, and outcome variables (negative affect about the Zimmerman trial and forgiveness for Mr. Zimmerman). In Study 2, 304 African American students completed measures of racial identity (centrality, private regard, and public regard), thought intrusions about the Zimmerman trial, negative affect, and forgiveness. In Study 1, higher RS-Race was either directly and/or indirectly (via thought intrusions) related to more negative affect and lower forgiveness. In Study 2, high racial centrality and low public regard either directly and/or indirectly (via thought intrusions) predicted more negative affect and lower forgiveness. RS-Race and specific components of racial identity are likely to sensitize African Americans to incidents of racism that happen to other African Americans, leading to negative psychological reactions when these events occur. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Testing hypotheses involving Cronbach's alpha using marginal models

NARCIS (Netherlands)

Kuijpers, R.E.; van der Ark, L.A.; Croon, M.A.

2013-01-01

We discuss the statistical testing of three relevant hypotheses involving Cronbach's alpha: one where alpha equals a particular criterion; a second testing the equality of two alpha coefficients for independent samples; and a third testing the equality of two alpha coefficients for dependent

A Bayesian decision procedure for testing multiple hypotheses in DNA microarray experiments.

Science.gov (United States)

Gómez-Villegas, Miguel A; Salazar, Isabel; Sanz, Luis

2014-02-01

DNA microarray experiments require the use of multiple hypothesis testing procedures because thousands of hypotheses are simultaneously tested. We deal with this problem from a Bayesian decision theory perspective. We propose a decision criterion based on an estimation of the number of false null hypotheses (FNH), taking as an error measure the proportion of the posterior expected number of false positives with respect to the estimated number of true null hypotheses. The methodology is applied to a Gaussian model when testing bilateral hypotheses. The procedure is illustrated with both simulated and real data examples and the results are compared to those obtained by the Bayes rule when an additive loss function is considered for each joint action and the generalized loss 0-1 function for each individual action. Our procedure significantly reduced the percentage of false negatives whereas the percentage of false positives remains at an acceptable level.

The Human Factor: Behavioral and Neural Correlates of Humanized Perception in Moral Decision Making

Science.gov (United States)

Majdandžić, Jasminka; Bauer, Herbert; Windischberger, Christian; Moser, Ewald; Engl, Elisabeth; Lamm, Claus

2012-01-01

The extent to which people regard others as full-blown individuals with mental states (“humanization”) seems crucial for their prosocial motivation towards them. Previous research has shown that decisions about moral dilemmas in which one person can be sacrificed to save multiple others do not consistently follow utilitarian principles. We hypothesized that this behavior can be explained by the potential victim’s perceived humanness and an ensuing increase in vicarious emotions and emotional conflict during decision making. Using fMRI, we assessed neural activity underlying moral decisions that affected fictitious persons that had or had not been experimentally humanized. In implicit priming trials, participants either engaged in mentalizing about these persons (Humanized condition) or not (Neutral condition). In subsequent moral dilemmas, participants had to decide about sacrificing these persons’ lives in order to save the lives of numerous others. Humanized persons were sacrificed less often, and the activation pattern during decisions about them indicated increased negative affect, emotional conflict, vicarious emotions, and behavioral control (pgACC/mOFC, anterior insula/IFG, aMCC and precuneus/PCC). Besides, we found enhanced effective connectivity between aMCC and anterior insula, which suggests increased emotion regulation during decisions affecting humanized victims. These findings highlight the importance of others’ perceived humanness for prosocial behavior - with aversive affect and other-related concern when imagining harming more “human-like” persons acting against purely utilitarian decisions. PMID:23082194

Data-driven efficient score tests for deconvolution hypotheses

NARCIS (Netherlands)

Langovoy, M.

2008-01-01

We consider testing statistical hypotheses about densities of signals in deconvolution models. A new approach to this problem is proposed. We constructed score tests for the deconvolution density testing with the known noise density and efficient score tests for the case of unknown density. The

Do we represent intentional action as recursively embedded? The answer must be empirical. A comment on Vicari and Adenzato (2014).

Science.gov (United States)

Martins, Mauricio D; Fitch, W Tecumseh

2015-12-15

The relationship between linguistic syntax and action planning is of considerable interest in cognitive science because many researchers suggest that "motor syntax" shares certain key traits with language. In a recent manuscript in this journal, Vicari and Adenzato (henceforth VA) critiqued Hauser, Chomsky and Fitch's 2002 (henceforth HCF's) hypothesis that recursion is language-specific, and that its usage in other domains is parasitic on language resources. VA's main argument is that HCF's hypothesis is falsified by the fact that recursion typifies the structure of intentional action, and recursion in the domain of action is independent of language. Here, we argue that VA's argument is incomplete, and that their formalism can be contrasted with alternative frameworks that are equally consistent with existing data. Therefore their conclusions are premature without further empirical testing and support. In particular, to accept VA's argument it would be necessary to demonstrate both that humans in fact represent self-embedding in the structure of intentional action, and that language is not used to construct these representations. Copyright © 2015 Elsevier Inc. All rights reserved.

Evaluation of hypotheses for the cause of the 1886 Charleston earthquake

Energy Technology Data Exchange (ETDEWEB)

White, R.M.; Long, L.T. (Law Environmental, Inc., Kennesaw, GA (USA); Georgia Inst. of Tech., Atlanta, GA (USA))

1989-10-01

This report describes a geophysical/geological investigation of the earth's crust at seismogenic depths in the Charleston, South Carolina area. This investigation was made for the purpose of narrowing the range of theories that have been used to explain the historic 1886 Charleston earthquake. Since a number of these theories are based on only a portion of the available data, we have established a comprehensive data set in order to allow these hypotheses to be subjected to the entire data set. Specifically, we combined existing and new gravity, magnetic and topographic data in grids of 128 km, 256 km and 1028 km on a side centered on Charleston. Seismic, geologic and drilling data were collected and summarized. A magnetotelluric survey consisting of 12 soundings interpreted to depths of over 40 kilometers defined the bottom of the rigid crust with assistance from seismic reflection and other data. A geologic model of the crust in the area of Charleston was constructed and it defined the locations of Triassic/Jurassic basins Paleozoic plutons in greater detail than has previously been achieved. 102 refs., 75 figs.

Evaluation of hypotheses for the cause of the 1886 Charleston earthquake

International Nuclear Information System (INIS)

White, R.M.; Long, L.T.

1989-10-01

This report describes a geophysical/geological investigation of the earth's crust at seismogenic depths in the Charleston, South Carolina area. This investigation was made for the purpose of narrowing the range of theories that have been used to explain the historic 1886 Charleston earthquake. Since a number of these theories are based on only a portion of the available data, we have established a comprehensive data set in order to allow these hypotheses to be subjected to the entire data set. Specifically, we combined existing and new gravity, magnetic and topographic data in grids of 128 km, 256 km and 1028 km on a side centered on Charleston. Seismic, geologic and drilling data were collected and summarized. A magnetotelluric survey consisting of 12 soundings interpreted to depths of over 40 kilometers defined the bottom of the rigid crust with assistance from seismic reflection and other data. A geologic model of the crust in the area of Charleston was constructed and it defined the locations of Triassic/Jurassic basins Paleozoic plutons in greater detail than has previously been achieved. 102 refs., 75 figs

Toward Valid Measurement of Stephen Pepper's World Hypotheses.

Science.gov (United States)

Johnson, John A.

Two measures of the "world hypotheses" of Stephen Pepper were mailed to 100 sociobiologists, 87 behaviorists, 79 personality psychologists, and 45 human developmentalists. The World Hypothesis Scale (WHS) was designed to measure Pepper's four world views: (1) formism; (2) mechanism; (3) organicism; and (4) contextualism. The…

What Is the Problem of Ad Hoc Hypotheses?

Science.gov (United States)

Bamford, Greg

1999-01-01

Philosophers' attempts to convincingly explicate the received view of an ad hoc hypothesis--that it accounts for only the observations it was designed to account for--have been unsuccessful. Familiar and firmer criteria for evaluating the hypotheses or modified theories so classified are characteristically available. Contains 41 references.…

Black/White Differences in Adolescent Drug Use: A Test of Six Hypotheses

Science.gov (United States)

Rote, Sunshine M.; Taylor, John

2014-01-01

Six specific hypotheses have been developed to account for why Caucasians have higher rates of drug use compared to African-Americans. This article utilizes data from a South Florida-based community study of 893 young adults (1998-2002) to test these hypotheses. Specifically, Caucasians (1) initiate drug use at younger ages than African-Americans…

Twelve testable hypotheses on the geobiology of weathering

Science.gov (United States)

S.L. Brantley; J.P. Megonigal; F.N. Scatena; Z. Balogh-Brunstad; R.T. Barnes; M.A. Bruns; P. van Cappelen; K. Dontsova; H.E. Hartnett; A.S. Hartshorn; A. Heimsath; E. Herndon; L. Jin; C.K. Keller; J.R. Leake; W.H. McDowell; F.C. Meinzer; T.J. Mozdzer; S. Petsch; J. Pett-Ridge; K.S. Pretziger; P.A. Raymond; C.S. Riebe; K. Shumaker; A. Sutton-Grier; R. Walter; K. Yoo

2011-01-01

Critical Zone (CZ) research investigates the chemical, physical, and biological processes that modulate the Earth's surface. Here, we advance 12 hypotheses that must be tested to improve our understanding of the CZ: (1) Solar-to-chemical conversion of energy by plants regulates flows of carbon, water, and nutrients through plant-microbe soil networks, thereby...

Transfer factor - hypotheses for its structure and function.

Science.gov (United States)

Shifrine, M; Scibienski, R

1975-01-01

Transfer factor (TF) is a dialyzable extract from primed lymphocytes that is able to transfer specific delayed hypersensitivity from one animal to another. On the basis of available data we suggest that TF is a polypeptide with a molecular weight below 15,000 daltons. We hypothesize that TF is the variable light or heavy chain domain of immunoglobulin: such a molecule conforms with the accepted properties of TF and also has the necessary specificity requirements. We also hypothesize that TF is part of a receptor site. beta-2-microglobulin, a molecule that is an integral part of cell surfaces, could be the anchor for TF. beta-2-microglobulin has homologies with the constant portion of immunoglobulin light or heavy chain and thus would combine with the variable domain (TF) to form a complete receptor site for a specific antigen. The properties of TF suggest its mode of action, which is discussed in detail in the text. The biologic advantages of TF is its ability to confer immediate (immunologie specific) protection while the 'normal' immune response develops.

A survey of etiologic hypotheses among testicular cancer researchers

DEFF Research Database (Denmark)

Stang, A; Trabert, B; Rusner, C

2015-01-01

Basic research results can provide new ideas and hypotheses to be examined in epidemiological studies. We conducted a survey among testicular cancer researchers on hypotheses concerning the etiology of this malignancy. All researchers on the mailing list of Copenhagen Testis Cancer Workshops...... and corresponding authors of PubMed-indexed articles identified by the search term 'testicular cancer' and published within 10 years (in total 2750 recipients) were invited to respond to an e-mail-based survey. Participants of the 8th Copenhagen Testis Cancer Workshop in May 2014 were subsequently asked to rate...... that scored as most plausible. We also present plans for improving the survey that may be repeated at a next international meeting of experts in testicular cancer. Overall 52 of 99 (53%) registered participants of the 8th Copenhagen Testis Cancer Workshop submitted the plausibility rating form. Fourteen of 27...

Traumatogenic Processes and Pathways to Mental Health Outcomes for Sexual Minorities Exposed to Bias Crime Information.

Science.gov (United States)

Lannert, Brittany K

2015-07-01

Vicarious traumatization of nonvictim members of communities targeted by bias crimes has been suggested by previous qualitative studies and often dominates public discussion following bias events, but proximal and distal responses of community members have yet to be comprehensively modeled, and quantitative research on vicarious responses is scarce. This comprehensive review integrates theoretical and empirical literatures in social, clinical, and physiological psychology in the development of a model of affective, cognitive, and physiological responses of lesbian, gay, and bisexual individuals upon exposure to information about bias crimes. Extant qualitative research in vicarious response to bias crimes is reviewed in light of theoretical implications and methodological limitations. Potential pathways to mental health outcomes are outlined, including accumulative effects of anticipatory defensive responding, multiplicative effects of minority stress, and putative traumatogenic physiological and cognitive processes of threat. Methodological considerations, future research directions, and clinical implications are also discussed. © The Author(s) 2014.

Landscape moderation of biodiversity patterns and processes - eight hypotheses

NARCIS (Netherlands)

Tscharntke, T.; Tylianakis, J.M.; Rand, T.A.; Didham, R.K.; Fahrig, L.; Batary, P.; Bengtsson, J.; Clough, Y.; Crist, T.O.; Dormann, C.; Ewers, R.M.; Frund, J.; Holt, R.D.; Holzschuh, A.; Klein, A.M.; Kleijn, D.; Kremen, C.; Landis, D.A.; Laurance, W.F.; Lindenmayer, D.B.; Scherber, C.; Sodhi, N.; Steffan-Dewenter, I.; Thies, C.; Putten, van der W.H.; Westphal, C.

2012-01-01

Understanding how landscape characteristics affect biodiversity patterns and ecological processes at local and landscape scales is critical for mitigating effects of global environmental change. In this review, we use knowledge gained from human-modified landscapes to suggest eight hypotheses, which

Towards Self-Learning Based Hypotheses Generation in Biomedical Text Domain.

Science.gov (United States)

Gopalakrishnan, Vishrawas; Jha, Kishlay; Xun, Guangxu; Ngo, Hung Q; Zhang, Aidong

2017-12-26

The overwhelming amount of research articles in the domain of bio-medicine might cause important connections to remain unnoticed. Literature Based Discovery is a sub-field within biomedical text mining that peruses these articles to formulate high confident hypotheses on possible connections between medical concepts. Although many alternate methodologies have been proposed over the last decade, they still suffer from scalability issues. The primary reason, apart from the dense inter-connections between biological concepts, is the absence of information on the factors that lead to the edge-formation. In this work, we formulate this problem as a collaborative filtering task and leverage a relatively new concept of word-vectors to learn and mimic the implicit edge-formation process. Along with single-class classifier, we prune the search-space of redundant and irrelevant hypotheses to increase the efficiency of the system and at the same time maintaining and in some cases even boosting the overall accuracy. We show that our proposed framework is able to prune up to 90% of the hypotheses while still retaining high recall in top-K results. This level of efficiency enables the discovery algorithm to look for higher-order hypotheses, something that was infeasible until now. Furthermore, the generic formulation allows our approach to be agile to performboth open and closed discovery.We also experimentally validate that the core data-structures upon which the system bases its decision has a high concordance with the opinion of the experts.This coupled with the ability to understand the edge formation process provides us with interpretable results without any manual intervention. The relevant JAVA codes are available at: https://github.com/vishrawas/Medline-Code_v2. vishrawa@buffalo.edukishlayj@buffalo.edu. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email

Concordant patterns of mtDNA and nuclear phylogeographic structure reveal Pleistocene vicariant event in the green crab Carcinus aestuarii across the Siculo-Tunisian Strait

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T. DELI

2016-07-01

Full Text Available This study focuses on the population genetic structure of the green crab Carcinus aestuarii along part of the African Mediterranean coast, with the main target to confirm genetic subdivision across the well documented genetic boundary of the Siculo-Tunisian Strait. For this purpose, the mitochondrial COI (cytochrome oxidase I gene and five polymorphic microsatellite loci were analysed in 144 and 120 specimens, respectively. Our results show the existence of two distinct haplogroups, separated by 16 mutational steps and revealed a non random distribution of the genetic variation along the African Mediterranean coast. Dating analyses, based on the use of different molecular clock models and rates, placed the divergence among both haplogroups at 1.91 Myr (95% HPD: 1.11–2.68 Myr to 0.69 Myr (95% HPD: 0.44–0.98 Myr. This range of divergence time estimation corresponds to the Early Pleistocene. The particular pattern of genetic divergence among Eastern and Western African Mediterranean populations of C. aestuarii, detected by 2-level AMOVA at the mitochondrial level, was consistent with that inferred from microsatellite analysis and suggests a vicariant event in C. aestuarii. Demographic reconstruction, inferred from mismatch distribution and BSP analyses, yielded different patterns of demographic history between both African Mediterranean groups. The distribution pattern of the two haplogroups across the African Mediterranean coast, along with results of Bayesian analysis of genetic structure revealing an intermediate geographic group between the two divergent groups of the African coast, support the hypothesis of a secondary contact between two historically isolated groups. Although this hypothetical contact zone, thought to be located near the Siculo-Tunisian Strait, still needs to be verified, the asymmetric gene flow from Western to Eastern African Mediterranean, as inferred by the results of a MIGRATE analysis, reinforces the previously

Paleogene radiation of a plant pathogenic mushroom.

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Martin P A Coetzee

Full Text Available The global movement and speciation of fungal plant pathogens is important, especially because of the economic losses they cause and the ease with which they are able to spread across large areas. Understanding the biogeography and origin of these plant pathogens can provide insights regarding their dispersal and current day distribution. We tested the hypothesis of a Gondwanan origin of the plant pathogenic mushroom genus Armillaria and the currently accepted premise that vicariance accounts for the extant distribution of the species.The phylogeny of a selection of Armillaria species was reconstructed based on Maximum Parsimony (MP, Maximum Likelihood (ML and Bayesian Inference (BI. A timeline was then placed on the divergence of lineages using a Bayesian relaxed molecular clock approach.Phylogenetic analyses of sequenced data for three combined nuclear regions provided strong support for three major geographically defined clades: Holarctic, South American-Australasian and African. Molecular dating placed the initial radiation of the genus at 54 million years ago within the Early Paleogene, postdating the tectonic break-up of Gondwana.The distribution of extant Armillaria species is the result of ancient long-distance dispersal rather than vicariance due to continental drift. As these finding are contrary to most prior vicariance hypotheses for fungi, our results highlight the important role of long-distance dispersal in the radiation of fungal pathogens from the Southern Hemisphere.

Testing Hypotheses About Glacial Cycles Against the Observational Record

DEFF Research Database (Denmark)

Kaufmann, Robert; Juselius, Katarina

2013-01-01

We estimate an identified cointegrated vector autoregression (CVAR) model of the climate system to test hypotheses about the physical mechanisms that may drive glacial cycles during the late Pleistocene. Results indicate that a permanent doubling of CO2 generates a 11.1oC rise in Antarctic...

The endemic Patagonian vespertilionid assemblage is a depauperate ecomorphological vicariant of species-rich neotropical assemblages

Institute of Scientific and Technical Information of China (English)

Analía L.GIM(E)NEZ; Norberto P. GIANNINI

2017-01-01

Vespertilionidae is the most diverse chiropteran family,and its diversity is concentrated in warm regions of the World;however,due to physiological and behavioral adaptations,these bats also dominate bat faunas in temperate regions.Here we performed a comparative study of vespertilionid assemblages from two broad regions of the New World,the cold and harsh Patagonia,versus the remaining temperate-to-subtropical,extra-Patagonian eco-regions of the South American Southern Cone.We took an ecomorphological approach and analyzed the craniodental morphological structure of these assemblages within a phylogenetic framework.We measured 17 craniodental linear variables from 447 specimens of 22 currently recognized vespertilionid species of the study regions.We performed a multivariate analysis to define the morphofunctional space,and calculated the pattern and degree of species packing for each assemblage.We assessed the importance of phylogeny and biogeography,and their impact on depauperate (Patagonian) versus rich (extra-Patagonian) vespertilionid assemblages as determinants of morphospace structuring.We implemented a sensitivity analysis associated to small samples of rare species.The morphological patterns were determined chiefly by the evolutionary history of the family.The Patagonian assemblage can be described as a structurally similar but comparatively depauperate ecomorphological version of those assemblages from neighboring extra-Patagonian eco-regions.The Patagonian assemblage seems to have formed by successively adding populations from Northern regions that eventually speciated in the region,leaving corresponding sisters (vicariants) in extraPatagonian eco-regions that continued to be characteristically richer.Despite being structurally akin,degree of species packing in Patagonia was comparatively very low,which may reflect the effect of limited dispersal success into a harsh region for bat survival.

Advancing the literature on designing audit and feedback interventions: identifying theory-informed hypotheses.

Science.gov (United States)

Colquhoun, Heather L; Carroll, Kelly; Eva, Kevin W; Grimshaw, Jeremy M; Ivers, Noah; Michie, Susan; Sales, Anne; Brehaut, Jamie C

2017-09-29

Audit and feedback (A&F) is a common strategy for helping health providers to implement evidence into practice. Despite being extensively studied, health care A&F interventions remain variably effective, with overall effect sizes that have not improved since 2003. Contributing to this stagnation is the fact that most health care A&F interventions have largely been designed without being informed by theoretical understanding from the behavioral and social sciences. To determine if the trend can be improved, the objective of this study was to develop a list of testable, theory-informed hypotheses about how to design more effective A&F interventions. Using purposive sampling, semi-structured 60-90-min telephone interviews were conducted with experts in theories related to A&F from a range of fields (e.g., cognitive, health and organizational psychology, medical decision-making, economics). Guided by detailed descriptions of A&F interventions from the health care literature, interviewees described how they would approach the problem of designing improved A&F interventions. Specific, theory-informed hypotheses about the conditions for effective design and delivery of A&F interventions were elicited from the interviews. The resulting hypotheses were assigned by three coders working independently into themes, and categories of themes, in an iterative process. We conducted 28 interviews and identified 313 theory-informed hypotheses, which were placed into 30 themes. The 30 themes included hypotheses related to the following five categories: A&F recipient (seven themes), content of the A&F (ten themes), process of delivery of the A&F (six themes), behavior that was the focus of the A&F (three themes), and other (four themes). We have identified a set of testable, theory-informed hypotheses from a broad range of behavioral and social science that suggest conditions for more effective A&F interventions. This work demonstrates the breadth of perspectives about A&F from non

Assessing the impact of vicarious experiences on preservice elementary science teacher efficacy and preservice elementary teacher efficacy

Science.gov (United States)

Wagler, Ronald Robert

Scope and method of study. The purpose of this study was to investigate the impact of vicarious experiences (preservice teacher field experiences) on perceived preservice science teacher efficacy and perceived preservice teacher efficacy. The participants for the study were 46 preservice elementary education students who were enrolled in CIED 3430 (Early Lab and Clinical Experience in Elementary Education II) at a large Midwestern state university and 20 classroom inservice teachers. A pretest was administered early in the spring 2007 semester, before the preservice teachers did their field experience and consisted of demographic questions and the STEBI-B. A posttest was administered at the end of the spring 2007 semester, after the preservice teachers had completed their field experiences, and consisted of demographic questions, a rating of the teachers they observed during their educational field experience, the STEBI-B and the TES. The field experience classroom inservice teachers provided personal, professional, and classroom data in the middle of the spring 2007 semester. All data were analyzed using analysis of variance (ANOVA) and analysis of covariance (ANCOVA). Findings and conclusions. Factors of gender, ethnicity, socioeconomic status and preservice teacher program placement were found to be significant predictors of preservice teachers' efficacy scores. Even though, in some cases, these factors negatively impacted preservice teacher efficacy, preservice teachers should be placed in these environments when support is most available. The Teacher Efficacy Scale (Gibson & Dembo, 1984) is invalid. Even the construct of a general teacher efficacy is questionable.

Automatic Bayes Factors for Testing Equality- and Inequality-Constrained Hypotheses on Variances.

Science.gov (United States)

Böing-Messing, Florian; Mulder, Joris

2018-05-03

In comparing characteristics of independent populations, researchers frequently expect a certain structure of the population variances. These expectations can be formulated as hypotheses with equality and/or inequality constraints on the variances. In this article, we consider the Bayes factor for testing such (in)equality-constrained hypotheses on variances. Application of Bayes factors requires specification of a prior under every hypothesis to be tested. However, specifying subjective priors for variances based on prior information is a difficult task. We therefore consider so-called automatic or default Bayes factors. These methods avoid the need for the user to specify priors by using information from the sample data. We present three automatic Bayes factors for testing variances. The first is a Bayes factor with equal priors on all variances, where the priors are specified automatically using a small share of the information in the sample data. The second is the fractional Bayes factor, where a fraction of the likelihood is used for automatic prior specification. The third is an adjustment of the fractional Bayes factor such that the parsimony of inequality-constrained hypotheses is properly taken into account. The Bayes factors are evaluated by investigating different properties such as information consistency and large sample consistency. Based on this evaluation, it is concluded that the adjusted fractional Bayes factor is generally recommendable for testing equality- and inequality-constrained hypotheses on variances.

Deep genetic divergences among Indo-Pacific populations of the coral reef sponge Leucetta chagosensis (Leucettidae): founder effects, vicariance, or both?

Science.gov (United States)

Wörheide, Gert; Epp, Laura S; Macis, Luciana

2008-01-26

An increasing number of studies demonstrate that genetic differentiation and speciation in the sea occur over much smaller spatial scales than previously appreciated given the wide distribution range of many morphologically defined coral reef invertebrate species and the presumed dispersal-enhancing qualities of ocean currents. However, knowledge about the processes that lead to population divergence and speciation is often lacking despite being essential for the understanding, conservation, and management of marine biodiversity. Sponges, a highly diverse, ecologically and economically important reef-invertebrate taxon, exhibit spatial trends in the Indo-West Pacific that are not universally reflected in other marine phyla. So far, however, processes generating those unexpected patterns are not understood. We unraveled the phylogeographic structure of the widespread Indo-Pacific coral reef sponge Leucetta chagosensis across its known geographic range using two nuclear markers: the rDNA internal transcribed spacers (ITS 1&2) and a fragment of the 28S gene, as well as the second intron of the ATP synthetase beta subunit-gene (ATPSb-iII). This enabled the detection of several deeply divergent clades congruent over both loci, one containing specimens from the Indian Ocean (Red Sea and Maldives), another one from the Philippines, and two other large and substructured NW Pacific and SW Pacific clades with an area of overlap in the Great Barrier Reef/Coral Sea. Reciprocally monophyletic populations were observed from the Philippines, Red Sea, Maldives, Japan, Samoa, and Polynesia, demonstrating long-standing isolation. Populations along the South Equatorial Current in the south-western Pacific showed isolation-by-distance effects. Overall, the results pointed towards stepping-stone dispersal with some putative long-distance exchange, consistent with expectations from low dispersal capabilities. We argue that both founder and vicariance events during the late Pliocene and

Vicariance and Oceanic Barriers Drive Contemporary Genetic Structure of Widespread Mangrove Species Sonneratia alba J. Sm in the Indo-West Pacific

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Alison K. S. Wee

2017-12-01

Full Text Available Patterns of genetic structure are essential for a comprehensive understanding of the evolution and biogeography of a species. Here, we investigated the genetic patterns of one of the most widespread and abundant mangrove species in the Indo-West Pacific, Sonneratia alba J. Sm., in order to gain insights into the ecological and evolutionary drivers of genetic structure in mangroves. We employed 11 nuclear microsatellite loci and two chloroplast regions to genotyped 25 S. alba populations. Our objectives were to (1 assess the level of genetic diversity and its geographic distribution; and (2 determine the genetic structure of the populations. Our results revealed significant genetic differentiation among populations. We detected a major genetic break between Indo-Malesia and Australasia, and further population subdivision within each oceanic region in these two major clusters. The phylogeographic patterns indicated a strong influence of vicariance, oceanic barriers and geographic distance on genetic structure. In addition, we found low genetic diversity and high genetic drift at range edge. This study advances the scope of mangrove biogeography by demonstrating a unique scenario whereby a widespread species has limited dispersal and high genetic divergence among populations.

Sub-kilometre (intra-crater) mounds in Utopia Planitia, Mars: character, occurrence and possible formation hypotheses

Science.gov (United States)

Soare, Richard J.; Conway, Susan J.; Pearce, Geoffrey D.; Costard, François; Séjourné, Antoine

2013-08-01

At the middle latitudes of Utopia Planitia (˜35-45°N; ˜65-101°E) hundreds of small-sized mounds located in sub-kilometre impact craters dot the landscape. Their shape varies from circular to crescentic and their height ranges from ˜10 to 50 m. Often, metre to decametre pitting is observed, as is metres-thick banding or stratification. Mound albedo is relatively high, i.e. ˜0.16. The plain's terrain in the region, previously linked to the latitude-dependent mantle (LDM) of ice-dust, displays pitting and albedo similar to the small intra-crater mounds. Some workers have suggested that the mounds and the plain's terrain share a common ice-dust origin. If so, then scrutinising the mounds could provide analogical insight on the key geological characteristics and spatial distribution of the LDM itself. Other workers have hypothesised that the mounds are eroded sedimentary landforms or periglacial mounds underlain by a perennial ice-core (closed-system pingos). In this article we develop and then discuss each of the three mound-hypotheses in a much more substantial manner than has been done hitherto. Towards this end we use high-resolution images, present a detailed regional-map of mound distribution and establish a regional platform of topographical analysis using MOLA data superposed on a large-scale CTX mosaic. Although the ice-dust hypothesis is consistent with some observations and measurements, we find that a (loess-based) sedimentary hypothesis shows greater plausibility. Of the three hypotheses evaluated, the pingo or periglacial one is the weakest.

Comparison for aphasic and control subjects of eye movements hypothesized in neurolinguistic programming.

Science.gov (United States)

Dooley, K O; Farmer, A

1988-08-01

Neurolinguistic programming's hypothesized eye movements were measured independently using videotapes of 10 nonfluent aphasic and 10 control subjects matched for age and sex. Chi-squared analysis indicated that eye-position responses were significantly different for the groups. Although earlier research has not supported the hypothesized eye positions for normal subjects, the present findings support the contention that eye-position responses may differ between neurologically normal and aphasic individuals.

Risk, innovation, electricity infrastructure and construction cost overruns: Testing six hypotheses

International Nuclear Information System (INIS)

Sovacool, Benjamin K.; Gilbert, Alex; Nugent, Daniel

2014-01-01

This study investigates the frequency and magnitude of cost and time overruns occurring during the construction of 401 electricity projects built between 1936 and 2014 in 57 countries. In aggregate, these projects required approximately $820 billion in investment, and amounted to 325,515 MW of installed capacity and 8495 km of transmission lines. We use this sample of projects to test six hypotheses about construction cost overruns related to (1) diseconomies of scale, (2) project delays, (3) technological learning, (4) regulation and markets, (5) decentralization and modularity, and (6) normalization of results to scale. We find that nuclear reactors are the riskiest technology in terms of mean cost escalation as a percentage of budget and frequency; that hydroelectric dams stand apart for their mean cost escalation in total dollars; that many of the hypotheses grounded in the literature appear wrong; and that financing, partnerships, modularity, and accountability may have more to do with overruns than technology. - Highlights: • Many hypotheses about construction overruns grounded in the literature appear wrong. • Nuclear reactors are the most prone to cost overruns as a percentage of budget and frequency. • Hydroelectric dams stand apart for their mean cost escalation in total dollars. • Solar and wind energy systems are least at risk to cost overruns

Yellow fever in Brazil: thoughts and hypotheses on the emergence in previously free areas

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Pedro Fernando da Costa Vasconcelos

2010-12-01

Full Text Available This article describes and discusses factors associated to the reemergence of yellow fever and its transmission dynamics in the states of São Paulo (Southeastern Brazil and Rio Grande do Sul (Southern during 2008 and 2009. The following factors have played a pivotal role for the reemergence of yellow fever in these areas: large susceptible human population; high prevalence of vectors and primary hosts (non-human primates; favorable climate conditions, especially increased rainfall; emergence of a new genetic lineage; and circulation of people and/or monkeys infected by virus. There is a need for an effective surveillance program to prevent the reemergence of yellow fever in other Brazilian states.

Experienced physicians benefit from analyzing initial diagnostic hypotheses

Science.gov (United States)

Bass, Adam; Geddes, Colin; Wright, Bruce; Coderre, Sylvain; Rikers, Remy; McLaughlin, Kevin

2013-01-01

Background Most incorrect diagnoses involve at least one cognitive error, of which premature closure is the most prevalent. While metacognitive strategies can mitigate premature closure in inexperienced learners, these are rarely studied in experienced physicians. Our objective here was to evaluate the effect of analytic information processing on diagnostic performance of nephrologists and nephrology residents. Methods We asked nine nephrologists and six nephrology residents at the University of Calgary and Glasgow University to diagnose ten nephrology cases. We provided presenting features along with contextual information, after which we asked for an initial diagnosis. We then primed participants to use either hypothetico-deductive reasoning or scheme-inductive reasoning to analyze the remaining case data and generate a final diagnosis. Results After analyzing initial hypotheses, both nephrologists and residents improved the accuracy of final diagnoses (31.1% vs. 65.6%, p inductive reasoning (odds ratio [95% confidence interval] 5.69 [1.59, 20.33], p = 0.07), whereas the performance of experienced nephrologists did not differ between strategies (odds ratio 0.57 [0.23, 1.39], p = 0.20). Discussion Experienced nephrologists and nephrology residents can improve their performance by analyzing initial diagnostic hypotheses. The explanation of the interaction between experience and the effect of different reasoning strategies is unclear, but may relate to preferences in reasoning strategy, or the changes in knowledge structure with experience. PMID:26451203

Kolmogorov's refined similarity hypotheses for turbulence and general stochastic processes

International Nuclear Information System (INIS)

Stolovitzky, G.; Sreenivasan, K.R.

1994-01-01

Kolmogorov's refined similarity hypotheses are shown to hold true for a variety of stochastic processes besides high-Reynolds-number turbulent flows, for which they were originally proposed. In particular, just as hypothesized for turbulence, there exists a variable V whose probability density function attains a universal form. Analytical expressions for the probability density function of V are obtained for Brownian motion as well as for the general case of fractional Brownian motion---the latter under some mild assumptions justified a posteriori. The properties of V for the case of antipersistent fractional Brownian motion with the Hurst exponent of 1/3 are similar in many details to those of high-Reynolds-number turbulence in atmospheric boundary layers a few meters above the ground. The one conspicuous difference between turbulence and the antipersistent fractional Brownian motion is that the latter does not possess the required skewness. Broad implications of these results are discussed

Host Lipid Mediators in Leprosy: The Hypothesized Contributions to Pathogenesis

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Carlos A. M. Silva

2018-02-01

Full Text Available The spectrum of clinical forms observed in leprosy and its pathogenesis are dictated by the host’s immune response against Mycobacterium leprae, the etiological agent of leprosy. Previous results, based on metabolomics studies, demonstrated a strong relationship between clinical manifestations of leprosy and alterations in the metabolism of ω3 and ω6 polyunsaturated fatty acids (PUFAs, and the diverse set of lipid mediators derived from PUFAs. PUFA-derived lipid mediators provide multiple functions during acute inflammation, and some lipid mediators are able to induce both pro- and anti-inflammatory responses as determined by the cell surface receptors being expressed, as well as the cell type expressing the receptors. However, little is known about how these compounds influence cellular immune activities during chronic granulomatous infectious diseases, such as leprosy. Current evidence suggests that specialized pro-resolving lipid mediators (SPMs are involved in the down-modulation of the innate and adaptive immune response against M. leprae and that alteration in the homeostasis of pro-inflammatory lipid mediators versus SPMs is associated with dramatic shifts in the pathogenesis of leprosy. In this review, we discuss the possible consequences and present new hypotheses for the involvement of ω3 and ω6 PUFA metabolism in the pathogenesis of leprosy. A specific emphasis is placed on developing models of lipid mediator interactions with the innate and adaptive immune responses and the influence of these interactions on the outcome of leprosy.

Constant conditional entropy and related hypotheses

International Nuclear Information System (INIS)

Ferrer-i-Cancho, Ramon; Dębowski, Łukasz; Moscoso del Prado Martín, Fermín

2013-01-01

Constant entropy rate (conditional entropies must remain constant as the sequence length increases) and uniform information density (conditional probabilities must remain constant as the sequence length increases) are two information theoretic principles that are argued to underlie a wide range of linguistic phenomena. Here we revise the predictions of these principles in the light of Hilberg’s law on the scaling of conditional entropy in language and related laws. We show that constant entropy rate (CER) and two interpretations for uniform information density (UID), full UID and strong UID, are inconsistent with these laws. Strong UID implies CER but the reverse is not true. Full UID, a particular case of UID, leads to costly uncorrelated sequences that are totally unrealistic. We conclude that CER and its particular cases are incomplete hypotheses about the scaling of conditional entropies. (letter)

A set working hypotheses towards a unified view of the universe

International Nuclear Information System (INIS)

Kecher, J.-C.; Vigier, J.P.; Centre National de la Recherche Scientifique, 75 - Paris; Paris-6 Univ., 75

1976-01-01

Some observation evidence (anisotropy and inhomogeneity of the Hubble constant, abnormal red shifts) led the authors to formulate working hypotheses compatible with these observations. The logics of these hypotheses led to consider the universe as a ''hierarchical'' universe similar to Charlier one, and to find the cause of the apparent expansion in the interactions affecting the path of the photons. As, in some cases, intrinsic red shifts are very important this reduces the distance of the considered objects and their absolute luminosity, and forces to link them with ordinary galaxies; a scheme of evolution of extragalactic objects is suggested, to account for the geometrical location of abnormal objects, and for some aspects of their morphology. Coherent picture of the universe might emerge from the suggested studies

Development of working hypotheses linking management of the Missouri River to population dynamics of Scaphirhynchus albus (pallid sturgeon)

Science.gov (United States)

Jacobson, Robert B.; Parsley, Michael J.; Annis, Mandy L.; Colvin, Michael E.; Welker, Timothy L.; James, Daniel A.

2016-01-20

This report documents a process of filtering of hypotheses that relate Missouri River Scaphirhynchus albus (pallid sturgeon) population dynamics to management actions including flow alterations, channel reconfigurations, and pallid sturgeon population augmentation. The filtering process was a partnership among U.S. Geological Survey, U.S. Army Corps of Engineers, and U.S. Fish and Wildlife Service to contribute to the Missouri River Recovery Management Plan process. The objective of the filtering process was to produce a set of hypotheses with high relevance to pallid sturgeon population dynamics and decision making on the Missouri River. The Missouri River Pallid Sturgeon Effects Analysis team filtered hundreds of potential hypotheses implicit in conceptual ecological models to develop a set of 40 candidate dominant hypotheses that were identified by experts as being important in pallid sturgeon population dynamics. Using a modified Delphi process and additional expert opinion, the team reduced this set of hypotheses to 23 working dominant hypotheses. We then matched the 23 hypotheses with management actions that could influence the biotic outcomes, resulting in as many as 176 potential effects between management actions and pallid sturgeon in the Missouri River. This number was consolidated to a candidate set of 53 working management hypotheses because some management actions applied to multiple life stages of the pallid sturgeon. We used an additional round of expert surveys to identify a set of 30 working management hypotheses. Finally, the set of working management hypotheses was filtered by the U.S. Army Corps of Engineers, Missouri River Recovery Program for actions that were within the agency’s authority and jurisdiction. This round resulted in a set of 21 hypotheses for initial modeling of linkages from management to pallid sturgeon population responses.

Corrigendum to: Bayesian evaluation of informative hypotheses in SEM using Mplus

NARCIS (Netherlands)

van de Schoot, R.; Verhoeven, Marjolein; Hoijtink, H.

2014-01-01

This paper corrects: van de Schoot, R., Verhoeven, M., & Hoijtink, H. (2013). Bayesian evaluation ofinformative hypotheses in SEM using Mplus: A black bear story. EuropeanJournal of Developmental Psychology, 10, 81 –98.

Proteomics Analysis Reveals Previously Uncharacterized Virulence Factors in Vibrio proteolyticus

Directory of Open Access Journals (Sweden)

Ann Ray

2016-07-01

Full Text Available Members of the genus Vibrio include many pathogens of humans and marine animals that share genetic information via horizontal gene transfer. Hence, the Vibrio pan-genome carries the potential to establish new pathogenic strains by sharing virulence determinants, many of which have yet to be characterized. Here, we investigated the virulence properties of Vibrio proteolyticus, a Gram-negative marine bacterium previously identified as part of the Vibrio consortium isolated from diseased corals. We found that V. proteolyticus causes actin cytoskeleton rearrangements followed by cell lysis in HeLa cells in a contact-independent manner. In search of the responsible virulence factor involved, we determined the V. proteolyticus secretome. This proteomics approach revealed various putative virulence factors, including active type VI secretion systems and effectors with virulence toxin domains; however, these type VI secretion systems were not responsible for the observed cytotoxic effects. Further examination of the V. proteolyticus secretome led us to hypothesize and subsequently demonstrate that a secreted hemolysin, belonging to a previously uncharacterized clan of the leukocidin superfamily, was the toxin responsible for the V. proteolyticus-mediated cytotoxicity in both HeLa cells and macrophages. Clearly, there remains an armory of yet-to-be-discovered virulence factors in the Vibrio pan-genome that will undoubtedly provide a wealth of knowledge on how a pathogen can manipulate host cells.

Deformational plagiocephaly in normal infants: a systematic review of causes and hypotheses.

Science.gov (United States)

De Bock, Freia; Braun, Volker; Renz-Polster, Herbert

2017-06-01

Deformational plagiocephaly (DP) is one of the most prevalent abnormal findings in infants and a frequent reason for parents to seek paediatric advice. To systematically review the literature and identify evidence and hypotheses on the aetiology and determinants of DP in otherwise healthy infants. Systematic keyword search in all major biomedical databases to identify peer-reviewed publications reporting (a) empirical research or (b) hypotheses on the aetiology of DP in healthy, term infants. 3150 studies published between 1985 and 2016 and containing relevant keywords were screened. In a two-pronged approach, results were summarised separately for the body of empirical work (22 studies) and the body of hypotheses (110 articles). Only a few empirical studies have examined risk factors in non-selected patient populations on a higher grade methodological level. The most commonly reported risk factors were: male gender, supine sleep position, limited neck rotation or preference in head position, first-born child, lower level of activity and lack of tummy time. Agreement between empirical studies was poor for most exposures, including supine sleep position, tummy time and use of car seats. The articles reporting hypotheses on the aetiology of DP cover a wide field of environmental and biological factors, but include little suggestions as to the potential influence of the everyday care environment of the baby. The evidence on the aetiology of DP is fragmentary and heterogeneous. In addition, factors possibly relevant to the development of DP have not been appreciated in the scientific discussion. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Controversial hypotheses on the relationship between researcher and informant in qualitative research.

Science.gov (United States)

Wilde, V

1992-02-01

This paper addresses methodological issues that emerged unexpectedly during a qualitative study set up to explore nurses' descriptions of difficult, challenging and satisfying experiences at work. The purpose of the study had been to look for critical factors influencing nurses' perceptions of their performance in specific situations, and their labelling of each event. Ten nurses were asked to describe in detail three events; a difficult situation in which they had coped well, a difficult situation in which they would like to have coped better, and a satisfying or rewarding situation. The critical incident technique was used. Rich descriptions were obtained, tape recorded, transcribed verbatum, and analysed by constant comparative analysis, following the principles of grounded theory. Some suprising hypotheses emerged regarding the methodology of the informal interview in qualitative research. This paper addresses these hypotheses, which focus on the interaction between the researcher and informant, the role conflict facing the nurse researcher, the effect of the researcher's past experience on the interaction, the use of counselling strategies and the principle of self-disclosure. These hypotheses were incidental to the original area of study and were more exciting in their emergence because of this.

Estimating the Proportion of True Null Hypotheses in Multiple Testing Problems

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Oluyemi Oyeniran

2016-01-01

Full Text Available The problem of estimating the proportion, π0, of the true null hypotheses in a multiple testing problem is important in cases where large scale parallel hypotheses tests are performed independently. While the problem is a quantity of interest in its own right in applications, the estimate of π0 can be used for assessing or controlling an overall false discovery rate. In this article, we develop an innovative nonparametric maximum likelihood approach to estimate π0. The nonparametric likelihood is proposed to be restricted to multinomial models and an EM algorithm is also developed to approximate the estimate of π0. Simulation studies show that the proposed method outperforms other existing methods. Using experimental microarray datasets, we demonstrate that the new method provides satisfactory estimate in practice.

Support for major hypotheses in invasion biology is uneven and declining

Czech Academy of Sciences Publication Activity Database

Jeschke, J.M.; Aparicio, L.G.; Haider, S.; Heger, T.; Lortie, C. J.; Pyšek, Petr; Strayer, D.L.

2012-01-01

Roč. 2012, č. 14 (2012), s. 1-20 ISSN 1619-0033 R&D Projects: GA ČR(CZ) GAP504/11/1028 Institutional support: RVO:67985939 Keywords : biological invasions * hypotheses * testing Subject RIV: EF - Botanics

Serial Learning Process: Test of Chaining, Position, and Dual-Process Hypotheses

Science.gov (United States)

Giurintano, S. L.

1973-01-01

The chaining, position, and dual-process hypotheses of serial learning (SL) as well as serial recall, reordering, and relearning of paired-associate learning were examined to establish learning patterns. Results provide evidence for dual-process hypothesis. (DS)

Skin Stem Cell Hypotheses and Long Term Clone Survival - Explored Using Agent-based Modelling

OpenAIRE

Li, X.; Upadhyay, A.K.; Bullock, A.J.; Dicolandrea, T.; Xu, J.; Binder, R.L.; Robinson, M.K.; Finlay, D.R.; Mills, K.J.; Bascom, C.C.; Kelling, C.K.; Isfort, R.J.; Haycock, J.W.; MacNeil, S.; Smallwood, R.H.

2013-01-01

Epithelial renewal in skin is achieved by the constant turnover and differentiation of keratinocytes. Three popular hypotheses have been proposed to explain basal keratinocyte regeneration and epidermal homeostasis: 1) asymmetric division (stem-transit amplifying cell); 2) populational asymmetry (progenitor cell with stochastic fate); and 3) populational asymmetry with stem cells. In this study, we investigated lineage dynamics using these hypotheses with a 3D agent-based model of the epiderm...

Mechanistic Mathematical Modeling Tests Hypotheses of the Neurovascular Coupling in fMRI.

Directory of Open Access Journals (Sweden)

Karin Lundengård

2016-06-01

Full Text Available Functional magnetic resonance imaging (fMRI measures brain activity by detecting the blood-oxygen-level dependent (BOLD response to neural activity. The BOLD response depends on the neurovascular coupling, which connects cerebral blood flow, cerebral blood volume, and deoxyhemoglobin level to neuronal activity. The exact mechanisms behind this neurovascular coupling are not yet fully investigated. There are at least three different ways in which these mechanisms are being discussed. Firstly, mathematical models involving the so-called Balloon model describes the relation between oxygen metabolism, cerebral blood volume, and cerebral blood flow. However, the Balloon model does not describe cellular and biochemical mechanisms. Secondly, the metabolic feedback hypothesis, which is based on experimental findings on metabolism associated with brain activation, and thirdly, the neurotransmitter feed-forward hypothesis which describes intracellular pathways leading to vasoactive substance release. Both the metabolic feedback and the neurotransmitter feed-forward hypotheses have been extensively studied, but only experimentally. These two hypotheses have never been implemented as mathematical models. Here we investigate these two hypotheses by mechanistic mathematical modeling using a systems biology approach; these methods have been used in biological research for many years but never been applied to the BOLD response in fMRI. In the current work, model structures describing the metabolic feedback and the neurotransmitter feed-forward hypotheses were applied to measured BOLD responses in the visual cortex of 12 healthy volunteers. Evaluating each hypothesis separately shows that neither hypothesis alone can describe the data in a biologically plausible way. However, by adding metabolism to the neurotransmitter feed-forward model structure, we obtained a new model structure which is able to fit the estimation data and successfully predict new

Vestigial Biological Structures: A Classroom-Applicable Test of Creationist Hypotheses

Science.gov (United States)

Senter, Phil; Ambrocio, Zenis; Andrade, Julia B.; Foust, Katanya K.; Gaston, Jasmine E.; Lewis, Ryshonda P.; Liniewski, Rachel M.; Ragin, Bobby A.; Robinson, Khanna L.; Stanley, Shane G.

2015-01-01

Lists of vestigial biological structures in biology textbooks are so short that some young-Earth creationist authors claim that scientists have lost confidence in the existence of vestigial structures and can no longer identify any verifiable ones. We tested these hypotheses with a method that is easily adapted to biology classes. We used online…

Political Participation Online: The Replacement and the Mobilisation Hypotheses Revisited

DEFF Research Database (Denmark)

Jensen, Jakob Linaa

2013-01-01

This article discusses the state of political participation online more than ten years after the Internet’s great popular breakthrough as an everyday medium. Denmark is used as a case study to critically re-examine the frequently discussed replacement and mobilisation hypotheses on behalf of the ...... participation, efficacy and social capital seem to have less impact on online political participation. In the end, these findings are related to more overall discussions on the democratising potential of the Internet.......This article discusses the state of political participation online more than ten years after the Internet’s great popular breakthrough as an everyday medium. Denmark is used as a case study to critically re-examine the frequently discussed replacement and mobilisation hypotheses on behalf...... of the Internet. The pure replacement hypothesis is rejected. Instead, it is found that the Internet still supplements rather than replaces other media, even among heavy Internet users. The Internet is one among several media used by ‘media omnivores’, and political participation online supplements rather than...

Deep genetic divergences among Indo-Pacific populations of the coral reef sponge Leucetta chagosensis (Leucettidae: Founder effects, vicariance, or both?

Directory of Open Access Journals (Sweden)

Epp Laura S

2008-01-01

Full Text Available Abstract Background An increasing number of studies demonstrate that genetic differentiation and speciation in the sea occur over much smaller spatial scales than previously appreciated given the wide distribution range of many morphologically defined coral reef invertebrate species and the presumed dispersal-enhancing qualities of ocean currents. However, knowledge about the processes that lead to population divergence and speciation is often lacking despite being essential for the understanding, conservation, and management of marine biodiversity. Sponges, a highly diverse, ecologically and economically important reef-invertebrate taxon, exhibit spatial trends in the Indo-West Pacific that are not universally reflected in other marine phyla. So far, however, processes generating those unexpected patterns are not understood. Results We unraveled the phylogeographic structure of the widespread Indo-Pacific coral reef sponge Leucetta chagosensis across its known geographic range using two nuclear markers: the rDNA internal transcribed spacers (ITS 1&2 and a fragment of the 28S gene, as well as the second intron of the ATP synthetase beta subunit-gene (ATPSb-iII. This enabled the detection of several deeply divergent clades congruent over both loci, one containing specimens from the Indian Ocean (Red Sea and Maldives, another one from the Philippines, and two other large and substructured NW Pacific and SW Pacific clades with an area of overlap in the Great Barrier Reef/Coral Sea. Reciprocally monophyletic populations were observed from the Philippines, Red Sea, Maldives, Japan, Samoa, and Polynesia, demonstrating long-standing isolation. Populations along the South Equatorial Current in the south-western Pacific showed isolation-by-distance effects. Overall, the results pointed towards stepping-stone dispersal with some putative long-distance exchange, consistent with expectations from low dispersal capabilities. Conclusion We argue that both

Causal null hypotheses of sustained treatment strategies: What can be tested with an instrumental variable?

Science.gov (United States)

Swanson, Sonja A; Labrecque, Jeremy; Hernán, Miguel A

2018-05-02

Sometimes instrumental variable methods are used to test whether a causal effect is null rather than to estimate the magnitude of a causal effect. However, when instrumental variable methods are applied to time-varying exposures, as in many Mendelian randomization studies, it is unclear what causal null hypothesis is tested. Here, we consider different versions of causal null hypotheses for time-varying exposures, show that the instrumental variable conditions alone are insufficient to test some of them, and describe additional assumptions that can be made to test a wider range of causal null hypotheses, including both sharp and average causal null hypotheses. Implications for interpretation and reporting of instrumental variable results are discussed.

Global changes of climate through human activities. New clues and hypotheses

Energy Technology Data Exchange (ETDEWEB)

Grassl, H

1988-02-01

New clues to world-wide changes of climate through human activities have been found or corroborated: Precipitation belts have shifted during the last 30 years; ozone over Antarctica in spring has fallen to its lowest level ever (1956); near-ground ozone in our latitudes has at least doubled in this century. Newly discussed hypotheses are: The oxidation capacity and, consequently, the purification capacity of the atmosphere decreases in the southern hemisphere owing above all to the increase in methane. Increased backscatter of solar radiation through low clouds during periods of turbid air in the atmosphere attenuates the greenhouse effect, the increase in icy clouds through condensation trails of jets flying at high altitudes intensifies the greenhouse effect of the atmosphere. The paper analyses these hypotheses and shows that the distinction between change of climate on the one hand and ecological damage on the other is not justifiable any longer. (orig./HSCH).

Using potential performance theory to test five hypotheses about meta-attribution.

Science.gov (United States)

Trafimow, David; Hunt, Gayle; Rice, Stephen; Geels, Kasha

2011-01-01

Based on I. Kant's (1991) distinction between perfect and imperfect duties and the attribution literature pertaining to that distinction, the authors proposed and tested 5 hypotheses about meta-attribution. More specifically, violations of perfect duties have been shown to arouse both more negative affect and stronger correspondent inferences than do violations of imperfect duties (e.g., D. Trafimow, I. K. Bromgard, K. A. Finlay, & T. Ketelaar, 2005). But when it comes to making meta-attributions-that is, guessing the attributions others would make-is the affect differential an advantage or a disadvantage? In addition to the null hypothesis of no effect, the authors proposed and tested additional hypotheses about how negative affect might increase or decrease the effectiveness of people's meta-attribution strategies and how even if there is no effect on strategy effectiveness, negative affect could increase or decrease the consistencies with which these strategies could be used.

INFLUENCES ON AND FROM THE SEGMENTATION OF NETWORKS - HYPOTHESES AND TESTS

NARCIS (Netherlands)

BAERVELDT, C; SNIJDERS, T

This article discusses (a) the influence of network structure on the diffusion of (new) cultural behavior within the network and (b) the influence of external events, especially of social programs, on the diffusion of (new) cultural behavior, and on the network structure. Hypotheses are formulated

Editorial: hypotheses about protein folding - the proteomic code and wonderfolds

Directory of Open Access Journals (Sweden)

Agutter Paul S

2009-12-01

Full Text Available Abstract Theoretical biology journals can contribute in many ways to the progress of knowledge. They are particularly well-placed to encourage dialogue and debate about hypotheses addressing problematical areas of research. An online journal provides an especially useful forum for such debate because of the option of posting comments within days of the publication of a contentious article.

Experienced physicians benefit from analyzing initial diagnostic hypotheses

Directory of Open Access Journals (Sweden)

Adam Bass

2013-03-01

Full Text Available Background: Most incorrect diagnoses involve at least one cognitive error, of which premature closure is the most prevalent. While metacognitive strategies can mitigate premature closure in inexperienced learners, these are rarely studied in experienced physicians. Our objective here was to evaluate the effect of analytic information processing on diagnostic performance of nephrologists and nephrology residents. Methods: We asked nine nephrologists and six nephrology residents at the University of Calgary and Glasgow University to diagnose ten nephrology cases. We provided presenting features along with contextual information, after which we asked for an initial diagnosis. We then primed participants to use either hypothetico-deductive reasoning or scheme-inductive reasoning to analyze the remaining case data and generate a final diagnosis. Results: After analyzing initial hypotheses, both nephrologists and residents improved the accuracy of final diagnoses (31.1% vs. 65.6%, p < 0.001, and 40.0% vs. 70.0%, p < 0.001, respectively. We found a significant interaction between experience and analytic processing strategy (p = 0.002: nephrology residents had significantly increased odds of diagnostic success when using scheme-inductive reasoning (odds ratio [95% confidence interval] 5.69 [1.59, 20.33], p = 0.007, whereas the performance of experienced nephrologists did not differ between strategies (odds ratio 0.57 [0.23, 1.39], p = 0.2. Discussion: Experienced nephrologists and nephrology residents can improve their performance by analyzing initial diagnostic hypotheses. The explanation of the interaction between experience and the effect of different reasoning strategies is unclear, but may relate to preferences in reasoning strategy, or the changes in knowledge structure with experience.

Endocardial tip cells in the human embryo - facts and hypotheses.

Directory of Open Access Journals (Sweden)

Mugurel C Rusu

Full Text Available Experimental studies regarding coronary embryogenesis suggest that the endocardium is a source of endothelial cells for the myocardial networks. As this was not previously documented in human embryos, we aimed to study whether or not endothelial tip cells could be correlated with endocardial-dependent mechanisms of sprouting angiogenesis. Six human embryos (43-56 days were obtained and processed in accordance with ethical regulations; immunohistochemistry was performed for CD105 (endoglin, CD31, CD34, α-smooth muscle actin, desmin and vimentin antibodies. Primitive main vessels were found deriving from both the sinus venosus and aorta, and were sought to be the primordia of the venous and arterial ends of cardiac microcirculation. Subepicardial vessels were found branching into the outer ventricular myocardium, with a pattern of recruiting α-SMA+/desmin+ vascular smooth muscle cells and pericytes. Endothelial sprouts were guided by CD31+/CD34+/CD105+/vimentin+ endothelial tip cells. Within the inner myocardium, we found endothelial networks rooted from endocardium, guided by filopodia-projecting CD31+/CD34+/CD105+/ vimentin+ endocardial tip cells. The myocardial microcirculatory bed in the atria was mostly originated from endocardium, as well. Nevertheless, endocardial tip cells were also found in cardiac cushions, but they were not related to cushion endothelial networks. A general anatomical pattern of cardiac microvascular embryogenesis was thus hypothesized; the arterial and venous ends being linked, respectively, to the aorta and sinus venosus. Further elongation of the vessels may be related to the epicardium and subepicardial stroma and the intramyocardial network, depending on either endothelial and endocardial filopodia-guided tip cells in ventricles, or mostly on endocardium, in atria.

Validity of the Environmental Kuznets Curve Hypotheses in Water Pollution A Case Study

Directory of Open Access Journals (Sweden)

Hediyeh Alishiri

2017-03-01

Full Text Available Among the different environmental pollutions, water pollution is of especial importance due to the rather unchanging supply of this vital resource on a global scale and because of the dire consequences of its pollution for human health. The relationship between water production and its pollution can thus established and used as a measure of environmental degradation. This relationship can then be captured and analyzed in terms of environmental Kuznets hypotheses. It may be claimed that the early stages of economic growth is associated with lower per capita income and water pollution but the trend is reversed with increasing per capita income and improved economic growth. The present study was conducted using the panel data technique and the Kuznets environmental hypotheses were examined for the two groups of developed and developing countries under the two scenarios of using either per capita GDP or the share of industry to the added value in GDP as an indicator of economic growth. Results indicate that under both scenarios, Kuznets hypotheses are confirmed when studying the situation in developing countries but refuted in the case of developed countries.

Ancestral state reconstructions require biological evidence to test evolutionary hypotheses: A case study examining the evolution of reproductive mode in squamate reptiles.

Science.gov (United States)

Griffith, Oliver W; Blackburn, Daniel G; Brandley, Matthew C; Van Dyke, James U; Whittington, Camilla M; Thompson, Michael B

2015-09-01

To understand evolutionary transformations it is necessary to identify the character states of extinct ancestors. Ancestral character state reconstruction is inherently difficult because it requires an accurate phylogeny, character state data, and a statistical model of transition rates and is fundamentally constrained by missing data such as extinct taxa. We argue that model based ancestral character state reconstruction should be used to generate hypotheses but should not be considered an analytical endpoint. Using the evolution of viviparity and reversals to oviparity in squamates as a case study, we show how anatomical, physiological, and ecological data can be used to evaluate hypotheses about evolutionary transitions. The evolution of squamate viviparity requires changes to the timing of reproductive events and the successive loss of features responsible for building an eggshell. A reversal to oviparity requires that those lost traits re-evolve. We argue that the re-evolution of oviparity is inherently more difficult than the reverse. We outline how the inviability of intermediate phenotypes might present physiological barriers to reversals from viviparity to oviparity. Finally, we show that ecological data supports an oviparous ancestral state for squamates and multiple transitions to viviparity. In summary, we conclude that the first squamates were oviparous, that frequent transitions to viviparity have occurred, and that reversals to oviparity in viviparous lineages either have not occurred or are exceedingly rare. As this evidence supports conclusions that differ from previous ancestral state reconstructions, our paper highlights the importance of incorporating biological evidence to evaluate model-generated hypotheses. © 2015 Wiley Periodicals, Inc.

Influence of Previous Knowledge in Torrance Tests of Creative Thinking

Directory of Open Access Journals (Sweden)

María Aranguren

2015-07-01

Full Text Available The aim of this work is to analyze the influence of study field, expertise and recreational activities participation in Torrance Tests of Creative Thinking (TTCT, 1974 performance. Several hypotheses were postulated to explore the possible effects of previous knowledge in TTCT verbal and TTCT figural university students’ outcomes. Participants in this study included 418 students from five study fields: Psychology;Philosophy and Literature, Music; Engineering; and Journalism and Advertising (Communication Sciences. Results found in this research seem to indicate that there in none influence of the study field, expertise and recreational activities participation in neither of the TTCT tests. Instead, the findings seem to suggest some kind of interaction between certain skills needed to succeed in specific studies fields and performance on creativity tests, such as the TTCT. These results imply that TTCT is a useful and valid instrument to measure creativity and that some cognitive process involved in innovative thinking can be promoted using different intervention programs in schools and universities regardless the students study field.

Hypotheses on citation practices as revealed in the literature of the ...

African Journals Online (AJOL)

Citations found in two historical articles, which appeared in Cancer Research, a top American Journal, were used to show both positive and negative attitudes towards my 22 historical publications on cancer carriage in the body. Therefore, scientific information concepts are cited critically and two hypotheses are advanced ...

Examining Preservice Science Teachers' Skills of Formulating Hypotheses and Identifying Variables

Science.gov (United States)

Aydogdu, Bülent

2015-01-01

The aim of this study is to examine preservice science teachers' skills of formulating hypotheses and identifying variables. The research has a phenomenological research design. The data was gathered qualitatively. In this study, preservice science teachers were first given two scenarios (Scenario-1 & Scenario-2) containing two different…

Isolation by distance and vicariance drive genetic structure of a coral reef fish in the Pacific Ocean.

Science.gov (United States)

Planes, S; Fauvelot, C

2002-02-01

We studied the genetic diversity of a coral reef fish species to investigate the origin of the differentiation. A total of 727 Acanthurus triostegus collected from 15 locations throughout the Pacific were analyzed for 20 polymorphic loci. The genetic structure showed limited internal disequilibrium within each population; 3.7% of the loci showed significant Hardy-Weinberg disequilibrium, mostly associated with Adh*, and we subsequently removed this locus from further analysis of geographic pattern. The genetic structure of A. triostegus throughout the tropical Pacific Ocean revealed a strong geographic pattern. Overall, there was significant population differentiation (multilocus F(ST) = 0.199), which was geographically structured according to bootstraps of neighbor-joining analysis on Nei's unbiased genetic distances and AMOVA analysis. The genetic structure revealed five geographic groups in the Pacific Ocean: western Pacific (Guam, Philippines, Palau, and Great Barrier Reef); central Pacific (Solomons, New Caledonia, and Fiji); and three groups made up of the eastern populations, namely Hawaiian Archipelago (north), Marquesas (equatorial), and southern French Polynesia (south) that incorporates Clipperton Island located in the northeastern Pacific. In addition, heterozygosity values were found to be geographically structured with higher values grouped within Polynesian and Clipperton populations, which exhibited lower population size. Finally, the genetic differentiation (F(ST)) was significantly correlated with geographic distance when populations from the Hawaiian and Marquesas archipelagos were separated from all the other locations. These results show that patterns of differentiation vary within the same species according to the spatial scale, with one group probably issued from vicariance, whereas the other followed a pattern of isolation by distance. The geographic pattern for A. triostegus emphasizes the diversity of the evolutionary processes that lead

Seed dormancy and germination - Emerging mechanisms and new hypotheses

Directory of Open Access Journals (Sweden)

Hiroyuki eNonogaki

2014-05-01

Full Text Available Seed dormancy has played a significant role in adaptation and evolution of seed plants. While its biological significance is clear, molecular mechanisms underlying seed dormancy induction, maintenance and alleviation still remain elusive. Intensive efforts have been made to investigate gibberellin and abscisic acid metabolism in seeds, which greatly contributed to the current understanding of seed dormancy mechanisms. Other mechanisms, which might be independent of hormones, or specific to the seed dormancy pathway, are also emerging from genetic analysis of seed dormancy mutants. These studies suggest that chromatin remodeling through histone ubiquitination, methylation and acetylation, which could lead to transcription elongation or gene silencing, may play a significant role in seed dormancy regulation. Small interfering RNA and/or long non-coding RNA might be a trigger of epigenetic changes at the seed dormancy or germination loci, such as DELAY OF GERMINATION1. While new mechanisms are emerging from genetic studies of seed dormancy, novel hypotheses are also generated from seed germination study with high throughput gene expression analysis. Recent studies on tissue-specific gene expression in tomato and Arabidopsis seeds, which suggested possible mechanosensing in the regulatory mechanisms, advanced our understanding of embryo-endosperm interaction and have potential to re-draw the traditional hypotheses or integrate them into a comprehensive scheme. The progress in basic seed science will enable knowledge translation, another frontier of research to be expanded for food and fuel production.

Differences between previously married and never married 'gay' men: family background, childhood experiences and current attitudes.

Science.gov (United States)

Higgins, Daryl J

2004-01-01

Despite a large body of literature on the development of sexual orientation, little is known about why some gay men have been (or remain) married to a woman. In the current study, a self-selected sample of 43 never married gay men ('never married') and 26 gay men who were married to a woman ('previously married') completed a self-report questionnaire. Hypotheses were based on five possible explanations for gay men's marriages: (a) differences in sexual orientation (i.e., bisexuality); (b) internalized homophobia; (c) religious intolerance; (d) confusion created because of childhood/adolescent sexual experiences; and/or (e) poor psychological adjustment. Previously married described their families' religious beliefs as more fundamentalist than never married. No differences were found between married' and never married' ratings of their sexual orientation and identity, and levels of homophobia and self-depreciation. Family adaptability and family cohesion and the degree to which respondents reported having experienced child maltreatment did not distinguish between previously married and never married. The results highlight how little is understood of the reasons why gay men marry, and the need to develop an adequate theoretical model.

Economic and evolutionary hypotheses for cross-population variation in parochialism

OpenAIRE

Daniel Jacob Hruschka; Joseph eHenrich

2013-01-01

Human populations differ reliably in the degree to which people favor family, friends and community members over strangers and outsiders. In the last decade, researchers have begun to propose several economic and evolutionary hypotheses for these cross-population differences in parochialism. In this paper, we outline major current theories and review recent attempts to test them. We also discuss the key methodological challenges in assessing these diverse economic and evolutionary theories...

Hypothesized eye movements of neurolinguistic programming: a statistical artifact.

Science.gov (United States)

Farmer, A; Rooney, R; Cunningham, J R

1985-12-01

Neurolinguistic programming's hypothesized eye-movements were measured independently from videotapes of 30 subjects, aged 15 to 76 yr., who were asked to recall visual pictures, recorded audio sounds, and textural objects. chi 2 indicated that subjects' responses were significantly different from those predicted. When chi 2 comparisons were weighted by number of eye positions assigned to each modality (3 visual, 3 auditory, 1 kinesthetic), subjects' responses did not differ significantly from the expected pattern. These data indicate that the eye-movement hypothesis may represent randomly occurring rather than sensory-modality-related positions.

Global mtDNA genetic structure and hypothesized invasion history of a major pest of citrus, Diaphorina citri (Hemiptera: Liviidae).

Science.gov (United States)

Luo, Yufa; Agnarsson, Ingi

2018-01-01

The Asian citrus psyllid Diaphorina citri Kuwayama is a key pest of citrus as the vector of the bacterium causing the "huanglongbing" disease (HLB). To assess the global mtDNA population genetic structure, and possible dispersal history of the pest, we investigated genetic variation at the COI gene collating newly collected samples with all previously published data. Our dataset consists of 356 colonies from 106 geographic sites worldwide. High haplotype diversity (H-mean = 0.702 ± 0.017), low nucleotide diversity (π-mean = 0.003), and significant positive selection (Ka/Ks = 32.92) were observed. Forty-four haplotypes (Hap) were identified, clustered into two matrilines: Both occur in southeastern and southern Asia, North and South America, and Africa; lineages A and B also occur in eastern and western Asia, respectively. The most abundant haplotypes were Hap4 in lineage A (35.67%), and Hap9 in lineage B (41.29%). The haplotype network identified them as the ancestral haplotypes within their respective lineages. Analysis of molecular variance showed significant genetic structure ( F ST  = 0.62, p  analysis suggests geographic structuring. We hypothesize a southern and/or southeastern Asia origin, three dispersal routes, and parallel expansions of two lineages. The hypothesized first route involved the expansion of lineage B from southern Asia into North America via West Asia. The second, the expansion of some lineage A individuals from Southeast Asia into East Asia, and the third involved both lineages from Southeast Asia spreading westward into Africa and subsequently into South America. To test these hypotheses and gain a deeper understanding of the global history of D. citri , more data-rich approaches will be necessary from the ample toolkit of next-generation sequencing (NGS). However, this study may serve to guide such sampling and in the development of biological control programs against the global pest D. citri .

Middle School Students' Science Self-Efficacy and Its Sources: Examination of Gender Difference

Science.gov (United States)

Kıran, Dekant; Sungur, Semra

2012-10-01

The main purpose of the present study is to investigate middle school students' science self-efficacy as well as its sources and outcomes as a function of gender. Bandura's hypothesized sources of self-efficacy (i.e., mastery experience, vicarious experience, verbal persuasion, and emotional arousal) in addition to being inviting with self and inviting with others were examined as sources of self-efficacy, while cognitive and metacognitive strategy use was examined as an outcome of self-efficacy. A total of 1,932 students participated in the study and were administered self-report instruments. Results showed that the relationship between science self-efficacy and its proposed sources does not change as a function of gender. All proposed sources, except for vicarious experience, were found to be significantly related to students' scientific self-efficacy. Moreover, girls were found to experience significantly more emotional arousal and to send positive messages to others more than boys. On the other hand, no gender difference was found concerning science self-efficacy and strategy use. The findings also revealed a positive association between science self-efficacy and strategy use. Overall, findings supported Bandura's conception of self-efficacy and suggested invitations as additional sources of self-efficacy.

The hippocampus and exploration: dynamically evolving behavior and neural representations

Science.gov (United States)

Johnson, Adam; Varberg, Zachary; Benhardus, James; Maahs, Anthony; Schrater, Paul

2012-01-01

We develop a normative statistical approach to exploratory behavior called information foraging. Information foraging highlights the specific processes that contribute to active, rather than passive, exploration and learning. We hypothesize that the hippocampus plays a critical role in active exploration through directed information foraging by supporting a set of processes that allow an individual to determine where to sample. By examining these processes, we show how information directed information foraging provides a formal theoretical explanation for the common hippocampal substrates of constructive memory, vicarious trial and error behavior, schema-based facilitation of memory performance, and memory consolidation. PMID:22848196

The hippocampus and exploration: dynamically evolving behavior and neural representations

Directory of Open Access Journals (Sweden)

Adam eJohnson

2012-07-01

Full Text Available We develop a normative statistical approach to exploratory behavior called information foraging. Information foraging highlights the specific processes that contribute to active, rather than passive, exploration and learning. We hypothesize that the hippocampus plays a critical role in active exploration through directed information foraging by supporting a set of processes that allow an individual to determine where to sample. By examining these processes, we show how information directed information foraging provides a formal theoretical explanation for the common hippocampal substrates of constructive memory, vicarious trial and error behavior, schema-based facilitation of memory performance, and memory consolidation.

NegaWatt 2011-2050 scenario - Hypotheses and method. Technical report, May 2014

International Nuclear Information System (INIS)

2014-05-01

This report proposes an analysis of the negaWatt 2011 scenario. It describes in detail the methodology adopted to elaborate this prospective scenario, and presents the major part of the hypotheses which structure this scenario. A first part presents the approach and methodology (constraints, scenario, model). The second part addresses the issue of energy saving and energy efficiency through a sector-based analysis (housing and office building, transports, industrial and agricultural production). The third part studies the substitution by renewable energies through a supply analysis: energy production based on biomass, renewable energies, and fissile and fossil energies. It outlines the major role of grids in the supply-demand balance. The results of the negaWatt 2011 scenario are presented in terms of final energy, primary energies, and impact on greenhouse gas emissions. Hypotheses and results related to the different sectors (building, transports, industry and agriculture, energy production) are given in appendix

Economic and evolutionary hypotheses for cross-population variation in parochialism.

Science.gov (United States)

Hruschka, Daniel J; Henrich, Joseph

2013-09-11

Human populations differ reliably in the degree to which people favor family, friends, and community members over strangers and outsiders. In the last decade, researchers have begun to propose several economic and evolutionary hypotheses for these cross-population differences in parochialism. In this paper, we outline major current theories and review recent attempts to test them. We also discuss the key methodological challenges in assessing these diverse economic and evolutionary theories for cross-population differences in parochialism.

Properties of hypothesis testing techniques and (Bayesian) model selection for exploration-based and theory-based (order-restricted) hypotheses.

Science.gov (United States)

Kuiper, Rebecca M; Nederhoff, Tim; Klugkist, Irene

2015-05-01

In this paper, the performance of six types of techniques for comparisons of means is examined. These six emerge from the distinction between the method employed (hypothesis testing, model selection using information criteria, or Bayesian model selection) and the set of hypotheses that is investigated (a classical, exploration-based set of hypotheses containing equality constraints on the means, or a theory-based limited set of hypotheses with equality and/or order restrictions). A simulation study is conducted to examine the performance of these techniques. We demonstrate that, if one has specific, a priori specified hypotheses, confirmation (i.e., investigating theory-based hypotheses) has advantages over exploration (i.e., examining all possible equality-constrained hypotheses). Furthermore, examining reasonable order-restricted hypotheses has more power to detect the true effect/non-null hypothesis than evaluating only equality restrictions. Additionally, when investigating more than one theory-based hypothesis, model selection is preferred over hypothesis testing. Because of the first two results, we further examine the techniques that are able to evaluate order restrictions in a confirmatory fashion by examining their performance when the homogeneity of variance assumption is violated. Results show that the techniques are robust to heterogeneity when the sample sizes are equal. When the sample sizes are unequal, the performance is affected by heterogeneity. The size and direction of the deviations from the baseline, where there is no heterogeneity, depend on the effect size (of the means) and on the trend in the group variances with respect to the ordering of the group sizes. Importantly, the deviations are less pronounced when the group variances and sizes exhibit the same trend (e.g., are both increasing with group number). © 2014 The British Psychological Society.

Independence of long-term contextual memory and short-term perceptual hypotheses: Evidence from contextual cueing of interrupted search.

Science.gov (United States)

Schlagbauer, Bernhard; Mink, Maurice; Müller, Hermann J; Geyer, Thomas

2017-02-01

Observers are able to resume an interrupted search trial faster relative to responding to a new, unseen display. This finding of rapid resumption is attributed to short-term perceptual hypotheses generated on the current look and confirmed upon subsequent looks at the same display. It has been suggested that the contents of perceptual hypotheses are similar to those of other forms of memory acquired long-term through repeated exposure to the same search displays over the course of several trials, that is, the memory supporting "contextual cueing." In three experiments, we investigated the relationship between short-term perceptual hypotheses and long-term contextual memory. The results indicated that long-term, contextual memory of repeated displays neither affected the generation nor the confirmation of short-term perceptual hypotheses for these displays. Furthermore, the analysis of eye movements suggests that long-term memory provides an initial benefit in guiding attention to the target, whereas in subsequent looks guidance is entirely based on short-term perceptual hypotheses. Overall, the results reveal a picture of both long- and short-term memory contributing to reliable performance gains in interrupted search, while exerting their effects in an independent manner.

De bruikbaarheid van de ‘shaken baby syndroom’-hypothese in het strafproces

NARCIS (Netherlands)

Hoving, R.A.

In het Nederlandse strafproces wordt regelmatig gebruik gemaakt van deskundigenbewijs van deskundigen die uitgaan van de ‘shaken baby syndroom’-hypothese om aan te tonen dat een verdachte een baby heeft mishandeld of gedood. In onder meer de Verenigde Staten en Engeland woedt een felle discussie

The Ranschburg Effect: Tests of the Guessing-Bias and Proactive Interference Hypotheses

Science.gov (United States)

Walsh, Michael F.; Schwartz, Marian

1977-01-01

The guessing-bias and proactive interference hypotheses of the Ranschburg Effect were investigated by giving three groups different instructions as to guessing during recall. Results failed to support the prediction that the effect should be reduced or eliminated on shift trials. Neither hypothesis received significant support. (CHK)

Use of hypotheses for analysis of variance Models: Challenging the current practice

NARCIS (Netherlands)

van Wesel, F.; Boeije, H.R.; Hoijtink, H

2013-01-01

In social science research, hypotheses about group means are commonly tested using analysis of variance. While deemed to be formulated as specifically as possible to test social science theory, they are often defined in general terms. In this article we use two studies to explore the current

Economic and evolutionary hypotheses for cross-population variation in parochialism

Directory of Open Access Journals (Sweden)

Daniel Jacob Hruschka

2013-09-01

Full Text Available Human populations differ reliably in the degree to which people favor family, friends and community members over strangers and outsiders. In the last decade, researchers have begun to propose several economic and evolutionary hypotheses for these cross-population differences in parochialism. In this paper, we outline major current theories and review recent attempts to test them. We also discuss the key methodological challenges in assessing these diverse economic and evolutionary theories for cross-population differences in parochialism.

Human female orgasm as evolved signal: a test of two hypotheses.

Science.gov (United States)

Ellsworth, Ryan M; Bailey, Drew H

2013-11-01

We present the results of a study designed to empirically test predictions derived from two hypotheses regarding human female orgasm behavior as an evolved communicative trait or signal. One hypothesis tested was the female fidelity hypothesis, which posits that human female orgasm signals a woman's sexual satisfaction and therefore her likelihood of future fidelity to a partner. The other was sire choice hypothesis, which posits that women's orgasm behavior signals increased chances of fertilization. To test the two hypotheses of human female orgasm, we administered a questionnaire to 138 females and 121 males who reported that they were currently in a romantic relationship. Key predictions of the female fidelity hypothesis were not supported. In particular, orgasm was not associated with female sexual fidelity nor was orgasm associated with male perceptions of partner sexual fidelity. However, faked orgasm was associated with female sexual infidelity and lower male relationship satisfaction. Overall, results were in greater support of the sire choice signaling hypothesis than the female fidelity hypothesis. Results also suggest that male satisfaction with, investment in, and sexual fidelity to a mate are benefits that favored the selection of orgasmic signaling in ancestral females.

The RNA-world and co-evolution hypotheses and the origin of life: Implications, research strategies and perspectives

Science.gov (United States)

Lahav, Noam

1993-12-01

The applicability of the RNA-world and co-evolution hypotheses to the study of the very first stages of the origin of life is discussed. The discussion focuses on the basic differences between the two hypotheses and their implications, with regard to the reconstruction methodology, ribosome emergence, balance between ribozymes and protein enzymes, and their major difficulties. Additional complexities of the two hypotheses, such as membranes and the energy source of the first reactions, are not treated in the present work. A central element in the proposed experimental strategies is the study of the catalytic activities of very small peptides and RNA-like oligomers, according to existing, as well as to yet-to-be-invented scenarios of the two hypotheses under consideration. It is suggested that the noveldirected molecular evolution technology, andmolecular computational modeling, can be applied to this research. This strategy is assumed to be essential for the suggested goal of future studies of the origin of life, namely, the establishment of a ‘Primordial Darwinian entity’.

Testing evolutionary hypotheses for phenotypic divergence using landscape genetics.

Science.gov (United States)

Funk, W Chris; Murphy, Melanie A

2010-02-01

Understanding the evolutionary causes of phenotypic variation among populations has long been a central theme in evolutionary biology. Several factors can influence phenotypic divergence, including geographic isolation, genetic drift, divergent natural or sexual selection, and phenotypic plasticity. But the relative importance of these factors in generating phenotypic divergence in nature is still a tantalizing and unresolved problem in evolutionary biology. The origin and maintenance of phenotypic divergence is also at the root of many ongoing debates in evolutionary biology, such as the extent to which gene flow constrains adaptive divergence (Garant et al. 2007) and the relative importance of genetic drift, natural selection, and sexual selection in initiating reproductive isolation and speciation (Coyne & Orr 2004). In this issue, Wang & Summers (2010) test the causes of one of the most fantastic examples of phenotypic divergence in nature: colour pattern divergence among populations of the strawberry poison frog (Dendrobates pumilio) in Panama and Costa Rica (Fig. 1). This study provides a beautiful example of the use of the emerging field of landscape genetics to differentiate among hypotheses for phenotypic divergence. Using landscape genetic analyses, Wang & Summers were able to reject the hypotheses that colour pattern divergence is due to isolation-by-distance (IBD) or landscape resistance. Instead, the hypothesis left standing is that colour divergence is due to divergent selection, in turn driving reproductive isolation among populations with different colour morphs. More generally, this study provides a wonderful example of how the emerging field of landscape genetics, which has primarily been applied to questions in conservation and ecology, now plays an essential role in evolutionary research.

A Decentralized Approach to the Formulation of Hypotheses: A Hierarchical Structural Model for a Prion Self-Assembled System

Science.gov (United States)

Wang, Mingyang; Zhang, Feifei; Song, Chao; Shi, Pengfei; Zhu, Jin

2016-07-01

Innovation in hypotheses is a key transformative driver for scientific development. The conventional centralized hypothesis formulation approach, where a dominant hypothesis is typically derived from a primary phenomenon, can, inevitably, impose restriction on the range of conceivable experiments and legitimate hypotheses, and ultimately impede understanding of the system of interest. We report herein the proposal of a decentralized approach for the formulation of hypotheses, through initial preconception-free phenomenon accumulation and subsequent reticular logical reasoning processes. The two-step approach can provide an unbiased, panoramic view of the system and as such should enable the generation of a set of more coherent and therefore plausible hypotheses. As a proof-of-concept demonstration of the utility of this open-ended approach, a hierarchical model has been developed for a prion self-assembled system, allowing insight into hitherto elusive static and dynamic features associated with this intriguing structure.

Bullying Victimization and Adolescent Self-Harm: Testing Hypotheses from General Strain Theory

Science.gov (United States)

Hay, Carter; Meldrum, Ryan

2010-01-01

Self-harm is widely recognized as a significant adolescent social problem, and recent research has begun to explore its etiology. Drawing from Agnew's (1992) social psychological strain theory of deviance, this study considers this issue by testing three hypotheses about the effects of traditional and cyber bullying victimization on deliberate…

Stigma models: Testing hypotheses of how images of Nevada are acquired and values are attached to them

Energy Technology Data Exchange (ETDEWEB)

Jenkins-Smith, H.C. [New Mexico Univ., Albuquerque, NM (United States)

1994-12-01

This report analyzes data from surveys on the effects that images associated with nuclear power and waste (i.e., nuclear images) have on people`s preference to vacation in Nevada. The analysis was stimulated by a model of imagery and stigma which assumes that information about a potentially hazardous facility generates signals that elicit negative images about the place in which it is located. Individuals give these images negative values (valences) that lessen their desire to vacation, relocate, or retire in that place. The model has been used to argue that the proposed Yucca Mountain high-level nuclear waste repository could elicit images of nuclear waste that would stigmatize Nevada and thus impose substantial economic losses there. This report proposes a revised model that assumes that the acquisition and valuation of images depend on individuals` ideological and cultural predispositions and that the ways in which new images will affect their preferences and behavior partly depend on these predispositions. The report tests these hypotheses: (1) individuals with distinct cultural and ideological predispositions have different propensities for acquiring nuclear images, (2) these people attach different valences to these images, (3) the variations in these valences are important, and (4) the valences of the different categories of images within an individual`s image sets for a place correlate very well. The analysis largely confirms these hypotheses, indicating that the stigma model should be revised to (1) consider the relevant ideological and cultural predispositions of the people who will potentially acquire and attach value to the image, (2) specify the kinds of images that previously attracted people to the host state, and (3) consider interactions between the old and potential new images of the place. 37 refs., 18 figs., 17 tabs.

Stigma models: Testing hypotheses of how images of Nevada are acquired and values are attached to them

International Nuclear Information System (INIS)

Jenkins-Smith, H.C.

1994-12-01

This report analyzes data from surveys on the effects that images associated with nuclear power and waste (i.e., nuclear images) have on people's preference to vacation in Nevada. The analysis was stimulated by a model of imagery and stigma which assumes that information about a potentially hazardous facility generates signals that elicit negative images about the place in which it is located. Individuals give these images negative values (valences) that lessen their desire to vacation, relocate, or retire in that place. The model has been used to argue that the proposed Yucca Mountain high-level nuclear waste repository could elicit images of nuclear waste that would stigmatize Nevada and thus impose substantial economic losses there. This report proposes a revised model that assumes that the acquisition and valuation of images depend on individuals' ideological and cultural predispositions and that the ways in which new images will affect their preferences and behavior partly depend on these predispositions. The report tests these hypotheses: (1) individuals with distinct cultural and ideological predispositions have different propensities for acquiring nuclear images, (2) these people attach different valences to these images, (3) the variations in these valences are important, and (4) the valences of the different categories of images within an individual's image sets for a place correlate very well. The analysis largely confirms these hypotheses, indicating that the stigma model should be revised to (1) consider the relevant ideological and cultural predispositions of the people who will potentially acquire and attach value to the image, (2) specify the kinds of images that previously attracted people to the host state, and (3) consider interactions between the old and potential new images of the place. 37 refs., 18 figs., 17 tabs

Educational Transitions in Israel: A Test of the Industrialization and Credentialism Hypotheses.

Science.gov (United States)

Shavit, Yossi; Kraus, Vered

1990-01-01

Explores the industrialization and credentialism hypotheses and predictions of educational attainment levels. Finds the effects of the father's education and occupation were stable for those attending school in the 1940s, 1950s, and 1960s. Notes that the effects of ethnicity declined in the transition from primary to secondary school. (NL)

Kolmogorov similarity hypotheses for scalar fields: sampling intermittent turbulent mixing in the ocean and galaxy

International Nuclear Information System (INIS)

Gibson, C.H.

1991-01-01

Kolmogorov's three universal similarity hypotheses are extrapolated to describe scalar fields like temperature mixed by turbulence. The analogous first and second hypotheses for scalars include the effects of Prandtl number and rate-of-strain mixing. Application of velocity and scalar similarity hypotheses to the ocean must take into account the damping of active turbulence by density stratification and the Earth's rotation to form fossil turbulence. By the analogous Kolmogorov third hypothesis for scalars, temperature dissipation rates χ averaged over lengths r > L K should be lognormally distributed with intermittency factors σ 2 that increase with increasing turbulence energy length scales L O as σ ln r 2 approx = μ θ ln(L O /r). Tests of kolmogorovian velocity and scalar universal similarity hypotheses for very large ranges of turbulence length and timescales are provided by data from the ocean and the galactic interstellar medium. These ranges are from 1 to 9 decades in the ocean, and over 12 decades in the interstellar medium. The universal constant for turbulent mixing intermittency μ θ is estimated from oceanic data to be 0.44±0.01, which is remarkably close to estimates for Kolmorgorov's turbulence intermittency constant μ of 0.45±0.05 from galactic as well as atmospheric data. Extreme intermittency complicates the oceanic sampling problem, and may lead to quantitative and qualitative undersampling errors in estimates of mean oceanic dissipation rates and fluxes. Intermittency of turbulence and mixing in the interstellar medium may be a factor in the formation of stars. (author)

About hypotheses and paradigms: exploring the Discreetness-Chance Paradigm.

Science.gov (United States)

Kaellis, Eugene

2006-01-01

Hypotheses generally conform to paradigms which, over time, change, usually tardily, after they have become increasingly difficult to sustain under the impact of non-conforming evidence and alternative hypotheses, but more important, when they no longer are comfortably ensconced in the surrounding social-economic-political-cultural milieu. It is asserted that this milieu is the most important factor in shaping scientific theorizing. Some examples are cited: the rejection of the evidence that the world orbits around the sun (suspected by Pythagoras) in favor of centuries-long firm adherence to the Ptolemaic geocentric system; the early acceptance of Natural Selection in spite of its tautological essence and only conjectural supporting evidence, because it justified contemporaneous social-political ideologies as typified by, e.g., Spencer and Malthus. Economic, social, and cultural factors are cited as providing the ground, i.e., ideational substrate, for what is cited as the Discreetness-Chance Paradigm (DCP), that has increasingly dominated physics, biology, and medicine for over a century and which invokes small, discrete packets of energy/matter (quanta, genes, microorganisms, aberrant cells) functioning within an environment of statistical, not determined, causality. There is speculation on a possible paradigmatic shift from the DCP, which has fostered the proliferation, parallel with ("splitting") taxonomy, of alleged individual disease entities, their diagnoses, and, when available, their specific remedies, something particularly prominent in, e.g., psychiatry's Diagnostic and Statistical Manual, a codified compendium of alleged mental and behavioral disorders, but evident in any textbook of diagnosis and treatment of physical ailments. This presumed paradigm shift may be reflected in Western medicine, presently increasingly empirical and atomized, towards a growing acceptance of a more generalized, subject-oriented, approach to health and disease, a non

Limits on hypothesizing new quantum numbers

International Nuclear Information System (INIS)

Goldstein, G.R.; Moravcsik, M.J.

1986-01-01

According to a recent theorem, for a general quantum-mechanical system undergoing a process, one can tell from measurements on this system whether or not it is characterized by a quantum number, the existence of which is unknown to the observer, even though the detecting equipment used by the observer is unable to distinguish among the various possible values of the ''secret'' quantum number and hence always averages over them. The present paper deals with situations in which this averaging is avoided and hence the ''secret'' quantum number remains ''secret.'' This occurs when a new quantum number is hypothesized in such a way that all the past measurements pertain to the system with one and the same value of the ''secret'' quantum number, or when the new quantum number is related to the old ones by a specific dynamical model providing a one-to-one correspondence. In the first of these cases, however, the one and the same state of the ''secret'' quantum number needs to be a nondegenerate one. If it is degenerate, the theorem can again be applied. This last feature provides a tool for experimentally testing symmetry breaking and the reestablishment of symmetries in asymptotic regions. The situation is illustrated on historical examples like isospin and strangeness, as well as on some contemporary schemes involving spaces of higher dimensionality

Rhabdomyosarcoma Arising in a Previously Irradiated Field: An Analysis of 43 Patients

Energy Technology Data Exchange (ETDEWEB)

Dang, Nguyen D. [Department of Radiation Oncology, Baylor College of Medicine, Houston, Texas (United States); Teh, Bin S. [Department of Radiation Oncology, The Methodist Hospital and Methodist Hospital Research Institute, Houston, Texas (United States); Paulino, Arnold C., E-mail: apaulino@tmhs.org [Department of Radiation Oncology, The Methodist Hospital and Methodist Hospital Research Institute, Houston, Texas (United States)

2013-03-01

Patients with soft tissue sarcomas that arise from previously irradiated fields have traditionally been reported to have a poor prognosis. In this report, we examined the characteristics and outcomes of patients who developed a rhabdomyosarcoma in a previously irradiated field (RMS-RIF); we hypothesize that these patients should have a better outcome compared to other postradiation soft tissue sarcomas as these tumors are chemosensitive and radiosensitive. A PubMed search of the literature from 1961-2010 yielded 33 studies with data for patients with RMS-RIF. The study included 43 patients with a median age of 6.5 years at the time of radiation therapy (RT) for the initial tumor. The median RT dose was 48 Gy. The median latency period, the time from RT to development of RMS-RIF, was 8 years. The 3-year overall survival for RMS-RIF was 42%. The 3-year overall survival was 66% for patients receiving chemotherapy and local treatment (surgery and/or RT) compared to 29% for those who had systemic treatment only or local treatment only (P=.049). Other factors associated with increased 3-year overall survival included retinoblastoma initial diagnosis (P<.001), age ≤18 years at diagnosis of RMS-RIF (P=.003), favorable site (P=.008), and stage 1 disease (P=.002). Age at time of RMS-RIF, retinoblastoma initial tumor, favorable site, stage 1 disease, and use of both systemic and local treatment were found to be favorable prognostic factors for 3-year overall survival.

Geophysical Data Define Boundaries and Sub-Regions of the Northern Gulf of Mexico Basin: Structural Histories and Causes are Hypothesized.

Science.gov (United States)

Kinsland, G. L.

2017-12-01

Within the last several years new types of geophysical data of the southern margin of the North American Craton and the Northern Gulf of Mexico Basin (NGoMB) have become available, e.g., results from the USArray experiment, high resolution satellite gravity data of the GoM itself and new heat flow data. These data when combined with previously existing geophysical data (gravity, magnetic and seismic) and shallow structural data offer new insights into the boundaries and sub-regions of the NGoMB. I offer hypotheses for the development of the structures of the buried crust and upper mantle which cause these features. Of particular interest might be my suggestion that the NGoMB might have extended in a southeasterly direction prior to the counter-clockwise rotation of the Yucatan Peninsula which ultimately resulted in the GoM.

An automated framework for hypotheses generation using literature

Directory of Open Access Journals (Sweden)

Abedi Vida

2012-08-01

Full Text Available Abstract Background In bio-medicine, exploratory studies and hypothesis generation often begin with researching existing literature to identify a set of factors and their association with diseases, phenotypes, or biological processes. Many scientists are overwhelmed by the sheer volume of literature on a disease when they plan to generate a new hypothesis or study a biological phenomenon. The situation is even worse for junior investigators who often find it difficult to formulate new hypotheses or, more importantly, corroborate if their hypothesis is consistent with existing literature. It is a daunting task to be abreast with so much being published and also remember all combinations of direct and indirect associations. Fortunately there is a growing trend of using literature mining and knowledge discovery tools in biomedical research. However, there is still a large gap between the huge amount of effort and resources invested in disease research and the little effort in harvesting the published knowledge. The proposed hypothesis generation framework (HGF finds “crisp semantic associations” among entities of interest - that is a step towards bridging such gaps. Methodology The proposed HGF shares similar end goals like the SWAN but are more holistic in nature and was designed and implemented using scalable and efficient computational models of disease-disease interaction. The integration of mapping ontologies with latent semantic analysis is critical in capturing domain specific direct and indirect “crisp” associations, and making assertions about entities (such as disease X is associated with a set of factors Z. Results Pilot studies were performed using two diseases. A comparative analysis of the computed “associations” and “assertions” with curated expert knowledge was performed to validate the results. It was observed that the HGF is able to capture “crisp” direct and indirect associations, and provide knowledge

An automated framework for hypotheses generation using literature.

Science.gov (United States)

Abedi, Vida; Zand, Ramin; Yeasin, Mohammed; Faisal, Fazle Elahi

2012-08-29

In bio-medicine, exploratory studies and hypothesis generation often begin with researching existing literature to identify a set of factors and their association with diseases, phenotypes, or biological processes. Many scientists are overwhelmed by the sheer volume of literature on a disease when they plan to generate a new hypothesis or study a biological phenomenon. The situation is even worse for junior investigators who often find it difficult to formulate new hypotheses or, more importantly, corroborate if their hypothesis is consistent with existing literature. It is a daunting task to be abreast with so much being published and also remember all combinations of direct and indirect associations. Fortunately there is a growing trend of using literature mining and knowledge discovery tools in biomedical research. However, there is still a large gap between the huge amount of effort and resources invested in disease research and the little effort in harvesting the published knowledge. The proposed hypothesis generation framework (HGF) finds "crisp semantic associations" among entities of interest - that is a step towards bridging such gaps. The proposed HGF shares similar end goals like the SWAN but are more holistic in nature and was designed and implemented using scalable and efficient computational models of disease-disease interaction. The integration of mapping ontologies with latent semantic analysis is critical in capturing domain specific direct and indirect "crisp" associations, and making assertions about entities (such as disease X is associated with a set of factors Z). Pilot studies were performed using two diseases. A comparative analysis of the computed "associations" and "assertions" with curated expert knowledge was performed to validate the results. It was observed that the HGF is able to capture "crisp" direct and indirect associations, and provide knowledge discovery on demand. The proposed framework is fast, efficient, and robust in

Vicariance, long-distance dispersal, and regional extinction-recolonization dynamics explain the disjunct circumpolar distribution of the arctic-alpine plant Silene acaulis.

Science.gov (United States)

Gussarova, Galina; Allen, Geraldine A; Mikhaylova, Yulia; McCormick, Laurie J; Mirré, Virginia; Marr, Kendrick L; Hebda, Richard J; Brochmann, Christian

2015-10-01

Many arctic-alpine species have vast geographic ranges, but these may encompass substantial gaps whose origins are poorly understood. Here we address the phylogeographic history of Silene acaulis, a perennial cushion plant with a circumpolar distribution except for a large gap in Siberia. We assessed genetic variation in a range-wide sample of 103 populations using plastid DNA (pDNA) sequences and AFLPs (amplified fragment length polymorphisms). We constructed a haplotype network and performed Bayesian phylogenetic analyses based on plastid sequences. We visualized AFLP patterns using principal coordinate analysis, identified genetic groups using the program structure, and estimated genetic diversity and rarity indices by geographic region. The history of the main pDNA lineages was estimated to span several glaciations. AFLP data revealed a distinct division between Beringia/North America and Europe/East Greenland. These two regions shared only one of 17 pDNA haplotypes. Populations on opposite sides of the Siberian range gap (Ural Mountains and Chukotka) were genetically distinct and appear to have resulted from postglacial leading-edge colonizations. We inferred two refugia in North America (Beringia and the southern Rocky Mountains) and two in Europe (central-southern Europe and northern Europe/East Greenland). Patterns in the East Atlantic region suggested transoceanic long-distance dispersal events. Silene acaulis has a highly dynamic history characterized by vicariance, regional extinction, and recolonization, with persistence in at least four refugia. Long-distance dispersal explains patterns across the Atlantic Ocean, but we found no evidence of dispersal across the Siberian range gap. © 2015 Botanical Society of America.

Williams Syndrome Hypersociability: A Neuropsychological Study of the Amygdala and Prefrontal Cortex Hypotheses

Science.gov (United States)

Capitao, Liliana; Sampaio, Adriana; Fernandez, Montse; Sousa, Nuno; Pinheiro, Ana; Goncalves, Oscar F.

2011-01-01

Individuals with Williams syndrome display indiscriminate approach towards strangers. Neuroimaging studies conducted so far have linked this social profile to structural and/or functional abnormalities in WS amygdala and prefrontal cortex. In this study, the neuropsychological hypotheses of amygdala and prefrontal cortex involvement in WS…

Testing Adaptive Hypotheses of Convergence with Functional Landscapes: A Case Study of Bone-Cracking Hypercarnivores

Science.gov (United States)

Tseng, Zhijie Jack

2013-01-01

Morphological convergence is a well documented phenomenon in mammals, and adaptive explanations are commonly employed to infer similar functions for convergent characteristics. I present a study that adopts aspects of theoretical morphology and engineering optimization to test hypotheses about adaptive convergent evolution. Bone-cracking ecomorphologies in Carnivora were used as a case study. Previous research has shown that skull deepening and widening are major evolutionary patterns in convergent bone-cracking canids and hyaenids. A simple two-dimensional design space, with skull width-to-length and depth-to-length ratios as variables, was used to examine optimized shapes for two functional properties: mechanical advantage (MA) and strain energy (SE). Functionality of theoretical skull shapes was studied using finite element analysis (FEA) and visualized as functional landscapes. The distribution of actual skull shapes in the landscape showed a convergent trend of plesiomorphically low-MA and moderate-SE skulls evolving towards higher-MA and moderate-SE skulls; this is corroborated by FEA of 13 actual specimens. Nevertheless, regions exist in the landscape where high-MA and lower-SE shapes are not represented by existing species; their vacancy is observed even at higher taxonomic levels. Results highlight the interaction of biomechanical and non-biomechanical factors in constraining general skull dimensions to localized functional optima through evolution. PMID:23734244

Testing adaptive hypotheses of convergence with functional landscapes: a case study of bone-cracking hypercarnivores.

Directory of Open Access Journals (Sweden)

Zhijie Jack Tseng

Full Text Available Morphological convergence is a well documented phenomenon in mammals, and adaptive explanations are commonly employed to infer similar functions for convergent characteristics. I present a study that adopts aspects of theoretical morphology and engineering optimization to test hypotheses about adaptive convergent evolution. Bone-cracking ecomorphologies in Carnivora were used as a case study. Previous research has shown that skull deepening and widening are major evolutionary patterns in convergent bone-cracking canids and hyaenids. A simple two-dimensional design space, with skull width-to-length and depth-to-length ratios as variables, was used to examine optimized shapes for two functional properties: mechanical advantage (MA and strain energy (SE. Functionality of theoretical skull shapes was studied using finite element analysis (FEA and visualized as functional landscapes. The distribution of actual skull shapes in the landscape showed a convergent trend of plesiomorphically low-MA and moderate-SE skulls evolving towards higher-MA and moderate-SE skulls; this is corroborated by FEA of 13 actual specimens. Nevertheless, regions exist in the landscape where high-MA and lower-SE shapes are not represented by existing species; their vacancy is observed even at higher taxonomic levels. Results highlight the interaction of biomechanical and non-biomechanical factors in constraining general skull dimensions to localized functional optima through evolution.

Coping with the Stigma of Mental Illness: Empirically-Grounded Hypotheses from Computer Simulations

Science.gov (United States)

Kroska, Amy; Har, Sarah K.

2011-01-01

This research demonstrates how affect control theory and its computer program, "Interact", can be used to develop empirically-grounded hypotheses regarding the connection between cultural labels and behaviors. Our demonstration focuses on propositions in the modified labeling theory of mental illness. According to the MLT, negative societal…

Drug-Resistant Epilepsy: Multiple Hypotheses, Few Answers

Directory of Open Access Journals (Sweden)

Fei Tang

2017-07-01

Full Text Available Epilepsy is a common neurological disorder that affects over 70 million people worldwide. Despite the recent introduction of new antiseizure drugs (ASDs, about one-third of patients with epilepsy have seizures refractory to pharmacotherapy. Early identification of patients who will become refractory to ASDs could help direct such patients to appropriate non-pharmacological treatment, but the complexity in the temporal patterns of epilepsy could make such identification difficult. The target hypothesis and transporter hypothesis are the most cited theories trying to explain refractory epilepsy, but neither theory alone fully explains the neurobiological basis of pharmacoresistance. This review summarizes evidence for and against several major theories, including the pharmacokinetic hypothesis, neural network hypothesis, intrinsic severity hypothesis, gene variant hypothesis, target hypothesis, and transporter hypothesis. The discussion is mainly focused on the transporter hypothesis, where clinical and experimental data are discussed on multidrug transporter overexpression, substrate profiles of ASDs, mechanism of transporter upregulation, polymorphisms of transporters, and the use of transporter inhibitors. Finally, future perspectives are presented for the improvement of current hypotheses and the development of treatment strategies as guided by the current understanding of refractory epilepsy.

From themes to hypotheses: following up with quantitative methods.

Science.gov (United States)

Morgan, David L

2015-06-01

One important category of mixed-methods research designs consists of quantitative studies that follow up on qualitative research. In this case, the themes that serve as the results from the qualitative methods generate hypotheses for testing through the quantitative methods. That process requires operationalization to translate the concepts from the qualitative themes into quantitative variables. This article illustrates these procedures with examples that range from simple operationalization to the evaluation of complex models. It concludes with an argument for not only following up qualitative work with quantitative studies but also the reverse, and doing so by going beyond integrating methods within single projects to include broader mutual attention from qualitative and quantitative researchers who work in the same field. © The Author(s) 2015.

Delinquency and Peer Acceptance in Adolescence: A Within-Person Test of Moffitt's Hypotheses

Science.gov (United States)

Rulison, Kelly L.; Kreager, Derek A.; Osgood, D. Wayne

2014-01-01

We tested 2 hypotheses derived from Moffitt's (1993) taxonomic theory of antisocial behavior, both of which are central to her explanation for the rise in delinquency during adolescence. We tested whether persistently delinquent individuals become more accepted by their peers during adolescence and whether individuals who abstain from delinquent…

How doctors generate diagnostic hypotheses: a study of radiological diagnosis with functional magnetic resonance imaging.

Directory of Open Access Journals (Sweden)

Marcio Melo

Full Text Available In medical practice, diagnostic hypotheses are often made by physicians in the first moments of contact with patients; sometimes even before they report their symptoms. We propose that generation of diagnostic hypotheses in this context is the result of cognitive processes subserved by brain mechanisms that are similar to those involved in naming objects or concepts in everyday life.To test this proposal we developed an experimental paradigm with functional magnetic resonance imaging (fMRI using radiological diagnosis as a model. Twenty-five radiologists diagnosed lesions in chest X-ray images and named non-medical targets (animals embedded in chest X-ray images while being scanned in a fMRI session. Images were presented for 1.5 seconds; response times (RTs and the ensuing cortical activations were assessed. The mean response time for diagnosing lesions was 1.33 (SD ±0.14 seconds and 1.23 (SD ±0.13 seconds for naming animals. 72% of the radiologists reported cogitating differential diagnoses during trials (3.5 seconds. The overall pattern of cortical activations was remarkably similar for both types of targets. However, within the neural systems shared by both stimuli, activation was significantly greater in left inferior frontal sulcus and posterior cingulate cortex for lesions relative to animals.Generation of diagnostic hypotheses and differential diagnoses made through the immediate visual recognition of clinical signs can be a fast and automatic process. The co-localization of significant brain activation for lesions and animals suggests that generating diagnostic hypotheses for lesions and naming animals are served by the same neuronal systems. Nevertheless, diagnosing lesions was cognitively more demanding and associated with more activation in higher order cortical areas. These results support the hypothesis that medical diagnoses based on prompt visual recognition of clinical signs and naming in everyday life are supported by similar

Exploration of miRNA families for hypotheses generation.

KAUST Repository

Kamanu, T.K.

2013-10-15

Technological improvements have resulted in increased discovery of new microRNAs (miRNAs) and refinement and enrichment of existing miRNA families. miRNA families are important because they suggest a common sequence or structure configuration in sets of genes that hint to a shared function. Exploratory tools to enhance investigation of characteristics of miRNA families and the functions of family-specific miRNA genes are lacking. We have developed, miRNAVISA, a user-friendly web-based tool that allows customized interrogation and comparisons of miRNA families for hypotheses generation, and comparison of per-species chromosomal distribution of miRNA genes in different families. This study illustrates hypothesis generation using miRNAVISA in seven species. Our results unveil a subclass of miRNAs that may be regulated by genomic imprinting, and also suggest that some miRNA families may be species-specific, as well as chromosome- and/or strand-specific.

Preventing the Development of Observationally Learnt Fears in Children by Devaluing the Model's Negative Response.

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Reynolds, Gemma; Field, Andy P; Askew, Chris

2015-10-01

Vicarious learning has become an established indirect pathway to fear acquisition. It is generally accepted that associative learning processes underlie vicarious learning; however, whether this association is a form of conditioned stimulus-unconditioned stimulus (CS-US) learning or stimulus-response (CS-CR) learning remains unclear. Traditionally, these types of learning can be dissociated in a US revaluation procedure. The current study explored the effects of post-vicarious learning US revaluation on acquired fear responses. Ninety-four children (46 males and 48 females) aged 6 to 10 years first viewed either a fear vicarious learning video or a neutral vicarious learning video followed by random allocation to one of three US revaluation conditions: inflation; deflation; or control. Inflation group children were presented with still images of the adults in the video and told that the accompanying sound and image of a very fast heart rate monitor belonged to the adult. The deflation group were shown the same images but with the sound and image of a normal heart rate. The control group received no US revaluation. Results indicated that inflating how scared the models appeared to be did not result in significant increases in children's fear beliefs, avoidance preferences, avoidance behavior or heart rate for animals above increases caused by vicarious learning. In contrast, US devaluation resulted in significant decreases in fear beliefs and avoidance preferences. Thus, the findings provide evidence that CS-US associations underpin vicarious learning and suggest that US devaluation may be a successful method for preventing children from developing fear beliefs following a traumatic vicarious learning episode with a stimulus.

Phylogeography of the endemic grasshopper genus Betiscoides (Lentulidae) in the South African Cape Floristic Region.

Science.gov (United States)

Matenaar, Daniela; Fingerle, Marcus; Heym, Eva; Wirtz, Sarah; Hochkirch, Axel

2018-01-01

Vicariance and dispersal are two important processes shaping biodiversity patterns. The South African Cape Floristic Region (CFR) is known for its high biotic diversity and endemism. However, studies on the phylogeography of endemic invertebrates in this biodiversity hotspot are still scarce. Here, we present a phylogenetic study of the flightless grasshopper genus Betiscoides, which is endemic to the CFR and strongly associated with restio plants (Restionaceae). We hypothesized that the genus originated in the southwestern part of the CFR, that differentiation within the genus is mainly an effect of vicariance and that the three known species only represent a minor fraction of the real genetic diversity of the genus. We inferred the phylogeny based on sequences of three mitochondrial and two nuclear genes from 99 Betiscoides specimens collected across the CFR. Furthermore, we conducted a SDIVA analysis to detect distributions of ancestral nodes and the possible spatial origin of these lineages. Strong differentiation among genetic lineages was shown. The ancestor of this genus was most likely distributed in the southwestern CFR. Five major lineages were detected, three of which were ancestrally distributed in the southwestern CFR. The ancestors of the two other lineages were distributed in the northern and eastern margins of the CFR. A total of 24 divergent evolutionary lineages were found, reflecting the geographical isolation of restio-dominated fynbos habitats. Dispersal played a more prominent role than expected in differentiation of Betiscoides. While the five main lineages were separated during a first phase via dispersal, differentiation occurred later and on smaller spatial scale, predominantly driven by isolation in montane refugia (i.e. vicariance). Our study also suggests that flightless insect taxa likely show high levels of differentiation in biodiversity hotspots with their taxonomy often being incomplete. Copyright © 2017 Elsevier Inc. All rights

Political market orientation and strategic party postures: Some hypotheses regarding profiles and relationship strengths

DEFF Research Database (Denmark)

Ormrod, Robert P.; Henneberg, Stephan C. M.

2007-01-01

an integrated construct of political marketing strategy which is exemplified by the derivation of hypotheses of the relationships between organizational stances on the one hand, and attitudinal and behavioural aspects of political market orientation on the other. We propose two levels of hypotheses: Firstly......Recently, the areas of strategic political marketing as well as political market orientation have been the subject of several conceptual articles (e.g., Henneberg 2006a; O'Cass 1996; Ormrod 2005, 2007). These have laid the theoretical foundations for further empirical work (e.g., Henneberg 2006b; O......'Cass 1996, 2001a, 2001b; Ormrod et al. 2007; Ormrod and Henneberg 2008 forthcoming). However, despite the close conceptual relatedness between some of these concepts they have yet to be integrated to provide a more nuanced picture which researchers but also political marketing practitioners can utilise...

Skin stem cell hypotheses and long term clone survival--explored using agent-based modelling.

Science.gov (United States)

Li, X; Upadhyay, A K; Bullock, A J; Dicolandrea, T; Xu, J; Binder, R L; Robinson, M K; Finlay, D R; Mills, K J; Bascom, C C; Kelling, C K; Isfort, R J; Haycock, J W; MacNeil, S; Smallwood, R H

2013-01-01

Epithelial renewal in skin is achieved by the constant turnover and differentiation of keratinocytes. Three popular hypotheses have been proposed to explain basal keratinocyte regeneration and epidermal homeostasis: 1) asymmetric division (stem-transit amplifying cell); 2) populational asymmetry (progenitor cell with stochastic fate); and 3) populational asymmetry with stem cells. In this study, we investigated lineage dynamics using these hypotheses with a 3D agent-based model of the epidermis. The model simulated the growth and maintenance of the epidermis over three years. The offspring of each proliferative cell was traced. While all lineages were preserved in asymmetric division, the vast majority were lost when assuming populational asymmetry. The third hypothesis provided the most reliable mechanism for self-renewal by preserving genetic heterogeneity in quiescent stem cells, and also inherent mechanisms for skin ageing and the accumulation of genetic mutation.

As the climatic disasters came. Hydrogen world view contra inflation of hypotheses; Als die Klimakatastrophen kamen. Wasserstoff-Weltbild kontra Hypothesen-Inflation

Energy Technology Data Exchange (ETDEWEB)

Gottfried, Rudolf J.

2009-07-01

The author of the contribution under consideration addresses to all persons which are interested scientifically and also are ready for leaving the well-trodden paths of conventional conceptions occasionally if it is shown that the paths mislead when continuing. In particular, here it is a matter of the controversy of the hydrogen conception of the world against hypothesis inflation. This book does not set up new hypotheses which are arranged in the numerously existing hypotheses according to the picture of the world. It is time to deliver the secured facts from the crusts of rigid hypotheses in order to look for new realizations without prejudices and in order to arrange the hypotheses meaningfully.

Discovery of previously unidentified genomic disorders from the duplication architecture of the human genome.

Science.gov (United States)

Sharp, Andrew J; Hansen, Sierra; Selzer, Rebecca R; Cheng, Ze; Regan, Regina; Hurst, Jane A; Stewart, Helen; Price, Sue M; Blair, Edward; Hennekam, Raoul C; Fitzpatrick, Carrie A; Segraves, Rick; Richmond, Todd A; Guiver, Cheryl; Albertson, Donna G; Pinkel, Daniel; Eis, Peggy S; Schwartz, Stuart; Knight, Samantha J L; Eichler, Evan E

2006-09-01

Genomic disorders are characterized by the presence of flanking segmental duplications that predispose these regions to recurrent rearrangement. Based on the duplication architecture of the genome, we investigated 130 regions that we hypothesized as candidates for previously undescribed genomic disorders. We tested 290 individuals with mental retardation by BAC array comparative genomic hybridization and identified 16 pathogenic rearrangements, including de novo microdeletions of 17q21.31 found in four individuals. Using oligonucleotide arrays, we refined the breakpoints of this microdeletion, defining a 478-kb critical region containing six genes that were deleted in all four individuals. We mapped the breakpoints of this deletion and of four other pathogenic rearrangements in 1q21.1, 15q13, 15q24 and 17q12 to flanking segmental duplications, suggesting that these are also sites of recurrent rearrangement. In common with the 17q21.31 deletion, these breakpoint regions are sites of copy number polymorphism in controls, indicating that these may be inherently unstable genomic regions.

"On Clocks and Clouds:" Confirming and Interpreting Climate Models as Scientific Hypotheses (Invited)

Science.gov (United States)

Donner, L.

2009-12-01

The certainty of climate change projected under various scenarios of emissions using general circulation models is an issue of vast societal importance. Unlike numerical weather prediction, a problem to which general circulation models are also applied, projected climate changes usually lie outside of the range of external forcings for which the models generating these changes have been directly evaluated. This presentation views climate models as complex scientific hypotheses and thereby frames these models within a well-defined process of both advancing scientific knowledge and recognizing its limitations. Karl Popper's Logik der Forschung (The Logic of Scientific Discovery, 1934) and 1965 essay “On Clocks and Clouds” capture well the methodologies and challenges associated with constructing climate models. Indeed, the process of a problem situation generating tentative theories, refined by error elimination, characterizes aptly the routine of general circulation model development. Limitations on certainty arise from the distinction Popper perceived in types of natural processes, which he exemplified by clocks, capable of exact measurement, and clouds, subject only to statistical approximation. Remarkably, the representation of clouds in general circulation models remains the key uncertainty in understanding atmospheric aspects of climate change. The asymmetry of hypothesis falsification by negation and much vaguer development of confidence in hypotheses consistent with some of their implications is an important practical challenge to confirming climate models. The presentation will discuss the ways in which predictions made by climate models for observable aspects of the present and past climate can be regarded as falsifiable hypotheses. The presentation will also include reasons why “passing” these tests does not provide complete confidence in predictions about the future by climate models. Finally, I will suggest that a “reductionist” view, in

Comparative phylogeography reveals deep lineages and regional evolutionary hotspots in the Mojave and Sonoran Deserts

Science.gov (United States)

Wood, Dustin A.; Vandergast, Amy G.; Barr, Kelly R.; Inman, Richard D.; Esque, Todd C.; Nussear, Kenneth E.; Fisher, Robert N.

2013-01-01

Aim: We explored lineage diversification within desert-dwelling fauna. Our goals were (1) to determine whether phylogenetic lineages and population expansions were consistent with younger Pleistocene climate fluctuation hypotheses or much older events predicted by pre-Pleistocene vicariance hypotheses, (2) to assess concordance in spatial patterns of genetic divergence and diversity among species and (3) to identify regional evolutionary hotspots of divergence and diversity and assess their conservation status. Location: Mojave, Colorado, and Sonoran Deserts, USA. Methods: We analysed previously published gene sequence data for twelve species. We used Bayesian gene tree methods to estimate lineages and divergence times. Within each lineage, we tested for population expansion and age of expansion using coalescent approaches. We mapped interpopulation genetic divergence and intra-population genetic diversity in a GIS to identify hotspots of highest genetic divergence and diversity and to assess whether protected lands overlapped with evolutionary hotspots. Results: In seven of the 12 species, lineage divergence substantially predated the Pleistocene. Historical population expansion was found in eight species, but expansion events postdated the Last Glacial Maximum (LGM) in only four. For all species assessed, six hotspots of high genetic divergence and diversity were concentrated in the Colorado Desert, along the Colorado River and in the Mojave/Sonoran ecotone. At least some proportion of the land within each recovered hotspot was categorized as protected, yet four of the six also overlapped with major areas of human development. Main conclusions: Most of the species studied here diversified into distinct Mojave and Sonoran lineages prior to the LGM – supporting older diversification hypotheses. Several evolutionary hotspots were recovered but are not strategically paired with areas of protected land. Long-term preservation of species-level biodiversity would

A robotic approach to understanding the role and the mechanism of vicarious trial-and-error in a T-maze task.

Science.gov (United States)

Matsuda, Eiko; Hubert, Julien; Ikegami, Takashi

2014-01-01

Vicarious trial-and-error (VTE) is a behavior observed in rat experiments that seems to suggest self-conflict. This behavior is seen mainly when the rats are uncertain about making a decision. The presence of VTE is regarded as an indicator of a deliberative decision-making process, that is, searching, predicting, and evaluating outcomes. This process is slower than automated decision-making processes, such as reflex or habituation, but it allows for flexible and ongoing control of behavior. In this study, we propose for the first time a robotic model of VTE to see if VTE can emerge just from a body-environment interaction and to show the underlying mechanism responsible for the observation of VTE and the advantages provided by it. We tried several robots with different parameters, and we have found that they showed three different types of VTE: high numbers of VTE at the beginning of learning, decreasing numbers afterward (similar VTE pattern to experiments with rats), low during the whole learning period, and high numbers all the time. Therefore, we were able to reproduce the phenomenon of VTE in a model robot using only a simple dynamical neural network with Hebbian learning, which suggests that VTE is an emergent property of a plastic and embodied neural network. From a comparison of the three types of VTE, we demonstrated that 1) VTE is associated with chaotic activity of neurons in our model and 2) VTE-showing robots were robust to environmental perturbations. We suggest that the instability of neuronal activity found in VTE allows ongoing learning to rebuild its strategy continuously, which creates robust behavior. Based on these results, we suggest that VTE is caused by a similar mechanism in biology and leads to robust decision making in an analogous way.

Out of Arabia: a complex biogeographic history of multiple vicariance and dispersal events in the gecko genus Hemidactylus (Reptilia: Gekkonidae).

Science.gov (United States)

Smíd, Jiří; Carranza, Salvador; Kratochvíl, Lukáš; Gvoždík, Václav; Nasher, Abdul Karim; Moravec, Jiří

2013-01-01

The geological history of the Arabian Peninsula has played a crucial role in shaping current diversity and distribution patterns of many Arabian and African faunal elements. The gecko genus Hemidactylus is not an exception. In this study, we provide an insight into the phylogeny and systematics of 45 recognized species of the so-called Arid clade of the genus Hemidactylus from Arabia, the Horn of Africa, the Levant and Iran. The material comprises 358 specimens sequenced for up to two mitochondrial (12S rRNA, cytochrome b) and four nuclear (mc1r, cmos, rag1, rag2) genes with 4766 bp of the concatenated alignment length. A robust calibrated phylogeny and reconstruction of historical biogeography are inferred. We link the history of this genus with major geological events that occurred in the region within the last 30 million years. Two basal divergences correspond with the break-ups of the Arabian and African landmasses and subsequent separation of Socotra from the Arabian mainland, respectively, segregating the genus by means of vicariance. Formation of the Red Sea led to isolation and subsequent radiation in the Arabian Peninsula, which was followed by multiple independent expansions: 13.1 Ma to Iran; 9.8 Ma to NE Africa; 8.2 to Socotra Archipelago; 7-7.3 Ma two colonizations to the Near East; 5.9 Ma to NE Africa; and 4.1 to Socotra. Moreover, using multiple genetic markers we detected cryptic diversity within the genus, particularly in south-western Arabia and the Ethiopian highlands, and confirmed the existence of at least seven new species in the area. These findings highlight the role of Arabia and the Horn of Africa as an important Hemidactylus diversity hotspot.

A robotic approach to understanding the role and the mechanism of vicarious trial-and-error in a T-maze task.

Directory of Open Access Journals (Sweden)

Eiko Matsuda

Full Text Available Vicarious trial-and-error (VTE is a behavior observed in rat experiments that seems to suggest self-conflict. This behavior is seen mainly when the rats are uncertain about making a decision. The presence of VTE is regarded as an indicator of a deliberative decision-making process, that is, searching, predicting, and evaluating outcomes. This process is slower than automated decision-making processes, such as reflex or habituation, but it allows for flexible and ongoing control of behavior. In this study, we propose for the first time a robotic model of VTE to see if VTE can emerge just from a body-environment interaction and to show the underlying mechanism responsible for the observation of VTE and the advantages provided by it. We tried several robots with different parameters, and we have found that they showed three different types of VTE: high numbers of VTE at the beginning of learning, decreasing numbers afterward (similar VTE pattern to experiments with rats, low during the whole learning period, and high numbers all the time. Therefore, we were able to reproduce the phenomenon of VTE in a model robot using only a simple dynamical neural network with Hebbian learning, which suggests that VTE is an emergent property of a plastic and embodied neural network. From a comparison of the three types of VTE, we demonstrated that 1 VTE is associated with chaotic activity of neurons in our model and 2 VTE-showing robots were robust to environmental perturbations. We suggest that the instability of neuronal activity found in VTE allows ongoing learning to rebuild its strategy continuously, which creates robust behavior. Based on these results, we suggest that VTE is caused by a similar mechanism in biology and leads to robust decision making in an analogous way.

Out of Arabia: a complex biogeographic history of multiple vicariance and dispersal events in the gecko genus Hemidactylus (Reptilia: Gekkonidae.

Directory of Open Access Journals (Sweden)

Jiří Smíd

Full Text Available The geological history of the Arabian Peninsula has played a crucial role in shaping current diversity and distribution patterns of many Arabian and African faunal elements. The gecko genus Hemidactylus is not an exception. In this study, we provide an insight into the phylogeny and systematics of 45 recognized species of the so-called Arid clade of the genus Hemidactylus from Arabia, the Horn of Africa, the Levant and Iran. The material comprises 358 specimens sequenced for up to two mitochondrial (12S rRNA, cytochrome b and four nuclear (mc1r, cmos, rag1, rag2 genes with 4766 bp of the concatenated alignment length. A robust calibrated phylogeny and reconstruction of historical biogeography are inferred. We link the history of this genus with major geological events that occurred in the region within the last 30 million years. Two basal divergences correspond with the break-ups of the Arabian and African landmasses and subsequent separation of Socotra from the Arabian mainland, respectively, segregating the genus by means of vicariance. Formation of the Red Sea led to isolation and subsequent radiation in the Arabian Peninsula, which was followed by multiple independent expansions: 13.1 Ma to Iran; 9.8 Ma to NE Africa; 8.2 to Socotra Archipelago; 7-7.3 Ma two colonizations to the Near East; 5.9 Ma to NE Africa; and 4.1 to Socotra. Moreover, using multiple genetic markers we detected cryptic diversity within the genus, particularly in south-western Arabia and the Ethiopian highlands, and confirmed the existence of at least seven new species in the area. These findings highlight the role of Arabia and the Horn of Africa as an important Hemidactylus diversity hotspot.

Theory of mind deficit in bipolar disorder: is it related to a previous history of psychotic symptoms?

Science.gov (United States)

Lahera, Guillermo; Montes, José Manuel; Benito, Adolfo; Valdivia, María; Medina, Elena; Mirapeix, Isabel; Sáiz-Ruiz, Jerónimo

2008-12-15

It has been hypothesized that a Theory of Mind (ToM) deficit could be a vulnerability marker for psychosis. Recent studies, however, have shown ToM deficits in affective relapses of bipolar disorder as well as in the euthymic phase. This study analyzes the relationship between ToM and a previous history of psychotic symptoms in bipolar disorder. ToM, sustained attention and executive functions were analyzed in 75 bipolar euthymic patients with three or more previous relapses (42 of them had a history of psychotic symptoms and 33 did not) and 48 healthy subjects. ToM was assessed with the Advanced Test by Happé. ToM performance was similar in bipolar patients with or without a history of psychotic symptoms, and in both cases it was significantly reduced as compared with the healthy control group. Similarly, both bipolar groups showed impaired sustained attention and executive functions. This general cognitive deficit partially explains the differences obtained in ToM. The ToM instrument used shows low sensitivity for assessing ToM in bipolar patients and it could partially reflect general cognitive functioning rather than a specific deficit in psychosis. ToM deficit is not a trait marker for psychosis, given that it is present in bipolar disorder regardless of a previous history of psychotic symptoms.

Message and source factors, market uncertainty and extrafunctional information processing : hypotheses and empirical evidence

NARCIS (Netherlands)

Song, X.M.

2001-01-01

This article examines how the perceived quality of extrafunctional information improves the innovation management process and contributes to success with innovations. Data collected from 420 Japanese managers and 270 US managers are used to test hypotheses about the antecedents of satisfaction with

The evolution of parental care in insects: A test of current hypotheses

Science.gov (United States)

Gilbert, James D J; Manica, Andrea

2015-01-01

Which sex should care for offspring is a fundamental question in evolution. Invertebrates, and insects in particular, show some of the most diverse kinds of parental care of all animals, but to date there has been no broad comparative study of the evolution of parental care in this group. Here, we test existing hypotheses of insect parental care evolution using a literature-compiled phylogeny of over 2000 species. To address substantial uncertainty in the insect phylogeny, we use a brute force approach based on multiple random resolutions of uncertain nodes. The main transitions were between no care (the probable ancestral state) and female care. Male care evolved exclusively from no care, supporting models where mating opportunity costs for caring males are reduced—for example, by caring for multiple broods—but rejecting the “enhanced fecundity” hypothesis that male care is favored because it allows females to avoid care costs. Biparental care largely arose by males joining caring females, and was more labile in Holometabola than in Hemimetabola. Insect care evolution most closely resembled amphibian care in general trajectory. Integrating these findings with the wealth of life history and ecological data in insects will allow testing of a rich vein of existing hypotheses. PMID:25825047

Gender Relations and Economic Development: Hypotheses about the Reversal of Fortune in EurAsia

NARCIS (Netherlands)

de Pleijt, A.M.; van Zanden, J.L.; Carmichael, S.G.

2016-01-01

This paper develops an interrelated set of hypotheses about the links between gender relations, family systems and economic development in EurAsia. Firstly, we briefly discuss a number of ideas from the recent literature about the links between gender relations and economic development. Secondly, we

Modelling desiccation cracking in a homogenous soil clay layer: comparison between different hypotheses on constitutive behaviour

Directory of Open Access Journals (Sweden)

Jommi Cristina

2016-01-01

Full Text Available Desiccation cracks are usually thought to start from the surface of an evaporating soil layer, and the available simplified models for crack initiation and propagation are based on this hypothesis. On the contrary, experimental results on a Dutch river clay showed that cracks in an evaporating soil layer may start and propagate below the surface, confirming earlier findings by other researchers. A simple one-dimensional model was set up to analyse the consequences of different hypotheses about the material behaviour on the crack onset in a homogenous soil layer undergoing surface drying. The results of the model show that dependence of the material behaviour on the rate of water content change is a necessary requirement for cracks to initiate below the surface. The conclusion suggests that, to properly understand cracking in an evaporating soil layer, an intrinsic time scale for the mechanical response must be accounted for, among all the other factors which were previously highlighted by other researchers. The key factor to predict crack onset below the surface is the dependence of the drying branch of the water retention curve of the compressible soil on the rate of drying, which would be justified by a rate dependent fabric evolution.

Testing Alternative Hypotheses Regarding the Association between Behavioral Inhibition and Language Development in Toddlerhood

Science.gov (United States)

Watts, Ashley K. Smith; Patel, Deepika; Corley, Robin P.; Friedman, Naomi P.; Hewitt, John K.; Robinson, JoAnn L.; Rhee, Soo H.

2014-01-01

Studies have reported an inverse association between language development and behavioral inhibition or shyness across childhood, but the direction of this association remains unclear. This study tested alternative hypotheses regarding this association in a large sample of toddlers. Data on behavioral inhibition and expressive and receptive…

Landscape moderation of biodiversity patterns and processes - eight hypotheses.

Science.gov (United States)

Tscharntke, Teja; Tylianakis, Jason M; Rand, Tatyana A; Didham, Raphael K; Fahrig, Lenore; Batáry, Péter; Bengtsson, Janne; Clough, Yann; Crist, Thomas O; Dormann, Carsten F; Ewers, Robert M; Fründ, Jochen; Holt, Robert D; Holzschuh, Andrea; Klein, Alexandra M; Kleijn, David; Kremen, Claire; Landis, Doug A; Laurance, William; Lindenmayer, David; Scherber, Christoph; Sodhi, Navjot; Steffan-Dewenter, Ingolf; Thies, Carsten; van der Putten, Wim H; Westphal, Catrin

2012-08-01

Understanding how landscape characteristics affect biodiversity patterns and ecological processes at local and landscape scales is critical for mitigating effects of global environmental change. In this review, we use knowledge gained from human-modified landscapes to suggest eight hypotheses, which we hope will encourage more systematic research on the role of landscape composition and configuration in determining the structure of ecological communities, ecosystem functioning and services. We organize the eight hypotheses under four overarching themes. Section A: 'landscape moderation of biodiversity patterns' includes (1) the landscape species pool hypothesis-the size of the landscape-wide species pool moderates local (alpha) biodiversity, and (2) the dominance of beta diversity hypothesis-landscape-moderated dissimilarity of local communities determines landscape-wide biodiversity and overrides negative local effects of habitat fragmentation on biodiversity. Section B: 'landscape moderation of population dynamics' includes (3) the cross-habitat spillover hypothesis-landscape-moderated spillover of energy, resources and organisms across habitats, including between managed and natural ecosystems, influences landscape-wide community structure and associated processes and (4) the landscape-moderated concentration and dilution hypothesis-spatial and temporal changes in landscape composition can cause transient concentration or dilution of populations with functional consequences. Section C: 'landscape moderation of functional trait selection' includes (5) the landscape-moderated functional trait selection hypothesis-landscape moderation of species trait selection shapes the functional role and trajectory of community assembly, and (6) the landscape-moderated insurance hypothesis-landscape complexity provides spatial and temporal insurance, i.e. high resilience and stability of ecological processes in changing environments. Section D: 'landscape constraints on

Method of Check of Statistical Hypotheses for Revealing of “Fraud” Point of Sale

Directory of Open Access Journals (Sweden)

T. M. Bolotskaya

2011-06-01

Full Text Available Application method checking of statistical hypotheses fraud Point of Sale working with purchasing cards and suspected of accomplishment of unauthorized operations is analyzed. On the basis of the received results the algorithm is developed, allowing receive an assessment of works of terminals in regime off-line.

Mesozoic fossils (>145 Mya suggest the antiquity of the subgenera of Daphnia and their coevolution with chaoborid predators

Directory of Open Access Journals (Sweden)

Taylor Derek J

2011-05-01

Full Text Available Abstract Background The timescale of the origins of Daphnia O. F. Mueller (Crustacea: Cladocera remains controversial. The origin of the two main subgenera has been associated with the breakup of the supercontinent Pangaea. This vicariance hypothesis is supported by reciprocal monophyly, present day associations with the former Gondwanaland and Laurasia regions, and mitochondrial DNA divergence estimates. However, previous multilocus nuclear DNA sequence divergence estimates at Daphnia. Results We describe new fossils of ephippia from the Khotont site in Mongolia associated with the Jurassic-Cretaceous boundary (about 145 MYA that are morphologically similar to several modern genera of the family Daphniidae, including the two major subgenera of Daphnia, i.e., Daphnia s. str. and Ctenodaphnia. The daphniid fossils co-occurred with fossils of the predaceous phantom midge (Chaoboridae. Conclusions Our findings indicate that the main subgenera of Daphnia are likely much older than previously known from fossils (at least 100 MY older or from nuclear DNA estimates of divergence. The results showing co-occurrence of the main subgenera far from the presumed Laurasia/Gondwanaland dispersal barrier shortly after formation suggests that vicariance from the breakup of Pangaea is an unlikely explanation for the origin of the main subgenera. The fossil impressions also reveal that the coevolution of a dipteran predator (Chaoboridae with the subgenus Daphnia is much older than previously known -- since the Mesozoic.

Hypotheses regarding the mechanisms of ayahuasca in the treatment of addictions.

Science.gov (United States)

Liester, Mitchell B; Prickett, James I

2012-01-01

Ayahuasca is a medicinal plant mixture utilized by indigenous peoples throughout the Amazon River basin for healing purposes. The "vine of the soul" or "vine of death," as it is known in South America, contains a combination of monoamine oxidase inhibitors and N,N-dimethyltryptamine (DMT). When ingested together, these medicines produce profound alterations in consciousness. Increasingly, ayahuasca is being utilized to treat addictions. However, the mechanism of action by which ayahuasca treats addictions remains unclear. We offer four hypotheses to explain possible biochemical, physiological, psychological, and transcendent mechanisms by which ayahuasca may exert its anti-addiction effects.

Independence of long-term contextual memory and short-term perceptual hypotheses: evidence from contextual cueing of interrupted search

OpenAIRE

Schlagbauer, B.; Mink, M.; Muller, Hermann J.; Geyer, T.

2017-01-01

Observers are able to resume an interrupted search trial faster relative to responding to a new, unseen display. This finding of rapid resumption is attributed to short-term perceptual hypotheses generated on the current look and confirmed upon subsequent looks at the same display. It has been suggested that the contents of perceptual hypotheses are similar to those of other forms of memory acquired long-term through repeated exposure to the same search displays over the course of several tri...

The evolution of parental care in insects: A test of current hypotheses.

Science.gov (United States)

Gilbert, James D J; Manica, Andrea

2015-05-01

Which sex should care for offspring is a fundamental question in evolution. Invertebrates, and insects in particular, show some of the most diverse kinds of parental care of all animals, but to date there has been no broad comparative study of the evolution of parental care in this group. Here, we test existing hypotheses of insect parental care evolution using a literature-compiled phylogeny of over 2000 species. To address substantial uncertainty in the insect phylogeny, we use a brute force approach based on multiple random resolutions of uncertain nodes. The main transitions were between no care (the probable ancestral state) and female care. Male care evolved exclusively from no care, supporting models where mating opportunity costs for caring males are reduced-for example, by caring for multiple broods-but rejecting the "enhanced fecundity" hypothesis that male care is favored because it allows females to avoid care costs. Biparental care largely arose by males joining caring females, and was more labile in Holometabola than in Hemimetabola. Insect care evolution most closely resembled amphibian care in general trajectory. Integrating these findings with the wealth of life history and ecological data in insects will allow testing of a rich vein of existing hypotheses. © 2015 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

A criterion for testing hypotheses about the covariance function of a stationary Gaussian stochastic process

OpenAIRE

Kozachenko, Yuriy; Troshki, Viktor

2015-01-01

We consider a measurable stationary Gaussian stochastic process. A criterion for testing hypotheses about the covariance function of such a process using estimates for its norm in the space $L_p(\\mathbb {T}),\\,p\\geq1$, is constructed.

Influence of Previous Knowledge, Language Skills and Domain-specific Interest on Observation Competency

Science.gov (United States)

Kohlhauf, Lucia; Rutke, Ulrike; Neuhaus, Birgit

2011-10-01

Many epoch-making biological discoveries (e.g. Darwinian Theory) were based upon observations. Nevertheless, observation is often regarded as `just looking' rather than a basic scientific skill. As observation is one of the main research methods in biological sciences, it must be considered as an independent research method and systematic practice of this method is necessary. Because observation skills form the basis of further scientific methods (e.g. experiments or comparisons) and children from the age of 4 years are able to independently generate questions and hypotheses, it seems possible to foster observation competency at a preschool level. To be able to provide development-adequate individual fostering of this competency, it is first necessary to assess each child's competency. Therefore, drawing on the recent literature, we developed in this study a competency model that was empirically evaluated within learners ( N = 110) from different age groups, from kindergarten to university. In addition, we collected data on language skills, domain-specific interest and previous knowledge to analyse coherence between these skills and observation competency. The study showed as expected that previous knowledge had a high impact on observation competency, whereas the influence of domain-specific interest was nonexistent. Language skills were shown to have a weak influence. By utilising the empirically validated model consisting of three dimensions (`Describing', `Scientific reasoning' and `Interpreting') and three skill levels, it was possible to assess each child's competency level and to develop and evaluate guided play activities to individually foster a child's observation competency.

Learned Helplessness and Depression in a Clinical Population: A Test of Two Behavioral Hypotheses

Science.gov (United States)

And Others; Price, Kenneth P.

1978-01-01

This study was undertaken to extend the learned helplessness phenomenon to a clinical population and to test the competing hypotheses of Seligman and Lewinsohn. 96 male hospitalized psychiatric and medical patients were randomly assigned to one of four experimental conditions. Results replicate the learned helplessness phenomenon in a group of…

Skin Stem Cell Hypotheses and Long Term Clone Survival – Explored Using Agent-based Modelling

Science.gov (United States)

Li, X.; Upadhyay, A. K.; Bullock, A. J.; Dicolandrea, T.; Xu, J.; Binder, R. L.; Robinson, M. K.; Finlay, D. R.; Mills, K. J.; Bascom, C. C.; Kelling, C. K.; Isfort, R. J.; Haycock, J. W.; MacNeil, S.; Smallwood, R. H.

2013-01-01

Epithelial renewal in skin is achieved by the constant turnover and differentiation of keratinocytes. Three popular hypotheses have been proposed to explain basal keratinocyte regeneration and epidermal homeostasis: 1) asymmetric division (stem-transit amplifying cell); 2) populational asymmetry (progenitor cell with stochastic fate); and 3) populational asymmetry with stem cells. In this study, we investigated lineage dynamics using these hypotheses with a 3D agent-based model of the epidermis. The model simulated the growth and maintenance of the epidermis over three years. The offspring of each proliferative cell was traced. While all lineages were preserved in asymmetric division, the vast majority were lost when assuming populational asymmetry. The third hypothesis provided the most reliable mechanism for self-renewal by preserving genetic heterogeneity in quiescent stem cells, and also inherent mechanisms for skin ageing and the accumulation of genetic mutation. PMID:23712735

Biological signatures of dynamic river networks from a coupled landscape evolution and neutral community model

Science.gov (United States)

Stokes, M.; Perron, J. T.

2017-12-01

Freshwater systems host exceptionally species-rich communities whose spatial structure is dictated by the topology of the river networks they inhabit. Over geologic time, river networks are dynamic; drainage basins shrink and grow, and river capture establishes new connections between previously separated regions. It has been hypothesized that these changes in river network structure influence the evolution of life by exchanging and isolating species, perhaps boosting biodiversity in the process. However, no general model exists to predict the evolutionary consequences of landscape change. We couple a neutral community model of freshwater organisms to a landscape evolution model in which the river network undergoes drainage divide migration and repeated river capture. Neutral community models are macro-ecological models that include stochastic speciation and dispersal to produce realistic patterns of biodiversity. We explore the consequences of three modes of speciation - point mutation, time-protracted, and vicariant (geographic) speciation - by tracking patterns of diversity in time and comparing the final result to an equilibrium solution of the neutral model on the final landscape. Under point mutation, a simple model of stochastic and instantaneous speciation, the results are identical to the equilibrium solution and indicate the dominance of the species-area relationship in forming patterns of diversity. The number of species in a basin is proportional to its area, and regional species richness reaches its maximum when drainage area is evenly distributed among sub-basins. Time-protracted speciation is also modeled as a stochastic process, but in order to produce more realistic rates of diversification, speciation is not assumed to be instantaneous. Rather, each new species must persist for a certain amount of time before it is considered to be established. When vicariance (geographic speciation) is included, there is a transient signature of increased

Age estimates for the buckwheat family Polygonaceae based on sequence data calibrated by fossils and with a focus on the amphi-Pacific Muehlenbeckia.

Directory of Open Access Journals (Sweden)

Tanja M Schuster

Full Text Available The buckwheat family Polygonaceae is a diverse group of plants and is a good model for investigating biogeography, breeding systems, coevolution with symbionts such as ants and fungi, functional trait evolution, hybridization, invasiveness, morphological plasticity, pollen morphology and wood anatomy. The main goal of this study was to obtain age estimates for Polygonaceae by calibrating a Bayesian phylogenetic analysis, using a relaxed molecular clock with fossil data. Based on the age estimates, we also develop hypotheses about the historical biogeography of the Southern Hemisphere group Muehlenbeckia. We are interested in addressing whether vicariance or dispersal could account for the diversification of Muehlenbeckia, which has a "Gondwanan" distribution. Eighty-one species of Polygonaceae were analysed with MrBayes to infer species relationships. One nuclear (nrITS and three chloroplast markers (the trnL-trnF spacer region, matK and ndhF genes were used. The molecular data were also analysed with Beast to estimate divergence times. Seven calibration points including fossil pollen and a leaf fossil of Muehlenbeckia were used to infer node ages. Results of the Beast analyses indicate an age of 110.9 (exponential/lognormal priors/118.7 (uniform priors million years (Myr with an uncertainty interval of (90.7-125.0 Myr for the stem age of Polygonaceae. This age is older than previously thought (Maastrichtian, approximately 65.5-70.6 Myr. The estimated divergence time for Muehlenbeckia is 41.0/41.6 (39.6-47.8 Myr and its crown clade is 20.5/22.3 (14.2-33.5 Myr old. Because the breakup of Gondwana occurred from 95-30 Myr ago, diversification of Muehlenbeckia is best explained by oceanic long-distance and maybe stepping-stone dispersal rather than vicariance. This study is the first to give age estimates for clades of Polygonaceae and functions as a jumping-off point for future studies on the historical biogeography of the family.

Laparoscopy After Previous Laparotomy

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Zulfo Godinjak

2006-11-01

Full Text Available Following the abdominal surgery, extensive adhesions often occur and they can cause difficulties during laparoscopic operations. However, previous laparotomy is not considered to be a contraindication for laparoscopy. The aim of this study is to present that an insertion of Veres needle in the region of umbilicus is a safe method for creating a pneumoperitoneum for laparoscopic operations after previous laparotomy. In the last three years, we have performed 144 laparoscopic operations in patients that previously underwent one or two laparotomies. Pathology of digestive system, genital organs, Cesarean Section or abdominal war injuries were the most common causes of previouslaparotomy. During those operations or during entering into abdominal cavity we have not experienced any complications, while in 7 patients we performed conversion to laparotomy following the diagnostic laparoscopy. In all patients an insertion of Veres needle and trocar insertion in the umbilical region was performed, namely a technique of closed laparoscopy. Not even in one patient adhesions in the region of umbilicus were found, and no abdominal organs were injured.

Testing contingency hypotheses in budgetary research: An evaluation of the use of moderated regression analysis

NARCIS (Netherlands)

Hartmann, Frank G.H.; Moers, Frank

1999-01-01

In the contingency literature on the behavioral and organizational effects of budgeting, use of the Moderated Regression Analysis (MRA) technique is prevalent. This technique is used to test contingency hypotheses that predict interaction effects between budgetary and contextual variables. This

Resilience Building in Students: The Role of Academic Self-Efficacy

Science.gov (United States)

Cassidy, Simon

2015-01-01

Self-efficacy relates to an individual's perception of their capabilities. It has a clear self-evaluative dimension leading to high or low perceived self-efficacy. Individual differences in perceived self-efficacy have been shown to be better predictors of performance than previous achievement or ability and seem particularly important when individuals face adversity. The study investigated the nature of the association between academic self-efficacy (ASE) and academic resilience. Undergraduate student participants (N = 435) were exposed to an adverse situation case vignette describing either personal or vicarious academic adversity. ASE was measured pre-exposure and academic resilience was measured post-exposure. ASE was correlated with, and a significant predictor of, academic resilience and students exhibited greater academic resilience when responding to vicarious adversity compared to personal adversity. Identifying constructs that are related to resilience and establishing the precise nature of how such constructs influence academic resilience will assist the development of interventions aimed at promoting resilience in students. PMID:26640447

Resilience Building in Students: The Role of Academic Self-Efficacy

Directory of Open Access Journals (Sweden)

Simon eCassidy

2015-11-01

Full Text Available Self-efficacy relates to an individual’s perception of their capabilities. It has a clear self-evaluative dimension leading to high or low perceived self-efficacy. Individual differences in perceived self-efficacy have been shown to be better predictors of performance than previous achievement or ability and seem particularly important when individuals face adversity. The study investigated the nature of the association between academic self-efficacy (ASE academic resilience. Undergraduate student participants (N=435 were exposed to an adverse situation case vignette describing either personal or vicarious academic adversity. ASE was measured pre-exposure and academic resilience was measured post- exposure. ASE was correlated with, and a significant predictor of, academic resilience and students exhibited greater academic resilience when responding to vicarious adversity compared to personal adversity. Identifying constructs that are related to resilience and establishing the precise nature of how such constructs influence resilience will assist the development of interventions aimed at promoting resilience in students.

In vivo strains in the femur of the Virginia opossum (Didelphis virginiana) during terrestrial locomotion: testing hypotheses of evolutionary shifts in mammalian bone loading and design.

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Butcher, Michael T; White, Bartholomew J; Hudzik, Nathan B; Gosnell, W Casey; Parrish, John H A; Blob, Richard W

2011-08-01

Terrestrial locomotion can impose substantial loads on vertebrate limbs. Previous studies have shown that limb bones from cursorial species of eutherian mammals experience high bending loads with minimal torsion, whereas the limb bones of non-avian reptiles (and amphibians) exhibit considerable torsion in addition to bending. It has been hypothesized that these differences in loading regime are related to the difference in limb posture between upright mammals and sprawling reptiles, and that the loading patterns observed in non-avian reptiles may be ancestral for tetrapod vertebrates. To evaluate whether non-cursorial mammals show loading patterns more similar to those of sprawling lineages, we measured in vivo strains in the femur during terrestrial locomotion of the Virginia opossum (Didelphis virginiana), a marsupial that uses more crouched limb posture than most mammals from which bone strains have been recorded, and which belongs to a clade phylogenetically between reptiles and the eutherian mammals studied previously. The presence of substantial torsion in the femur of opossums, similar to non-avian reptiles, would suggest that this loading regime likely reflects an ancestral condition for tetrapod limb bone design. Strain recordings indicate the presence of both bending and appreciable torsion (shear strain: 419.1 ± 212.8 με) in the opossum femur, with planar strain analyses showing neutral axis orientations that placed the lateral aspect of the femur in tension at the time of peak strains. Such mediolateral bending was unexpected for a mammal running with near-parasagittal limb kinematics. Shear strains were similar in magnitude to peak compressive axial strains, with opossum femora experiencing similar bending loads but higher levels of torsion compared with most previously studied mammals. Analyses of peak femoral strains led to estimated safety factor ranges of 5.1-7.2 in bending and 5.5-7.3 in torsion, somewhat higher than typical mammalian values

Interactions between domestic and export markets for softwood lumber and plywood: tests of six hypotheses.

Science.gov (United States)

David R. Darr

1981-01-01

Price formation in export markets and available data on export and domestic markets are discussed. The results of tests of several hypotheses about interactions between domestic and export markets are presented and interpreted from the standpoints of trade promotion and trade policy.

Utility of Krashen's Five Hypotheses in the Saudi Context of Foreign Language Acquisition/Learning

Science.gov (United States)

Gulzar, Malik Ajmal; Gulnaz, Fahmeeda; Ijaz, Attiya

2014-01-01

In the last twenty years, the paradigm that has dominated the discipline of language teaching is the SLA theory and Krashen's five hypotheses which are still proving flexible to accommodate earlier reforms. This paper reviews second language acquisition (SLA) theory to establish an understanding of its role in the EFL/ESL classrooms. Other areas…

Preoperative screening: value of previous tests.

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Macpherson, D S; Snow, R; Lofgren, R P

1990-12-15

To determine the frequency of tests done in the year before elective surgery that might substitute for preoperative screening tests and to determine the frequency of test results that change from a normal value to a value likely to alter perioperative management. Retrospective cohort analysis of computerized laboratory data (complete blood count, sodium, potassium, and creatinine levels, prothrombin time, and partial thromboplastin time). Urban tertiary care Veterans Affairs Hospital. Consecutive sample of 1109 patients who had elective surgery in 1988. At admission, 7549 preoperative tests were done, 47% of which duplicated tests performed in the previous year. Of 3096 previous results that were normal as defined by hospital reference range and done closest to the time of but before admission (median interval, 2 months), 13 (0.4%; 95% CI, 0.2% to 0.7%), repeat values were outside a range considered acceptable for surgery. Most of the abnormalities were predictable from the patient's history, and most were not noted in the medical record. Of 461 previous tests that were abnormal, 78 (17%; CI, 13% to 20%) repeat values at admission were outside a range considered acceptable for surgery (P less than 0.001, frequency of clinically important abnormalities of patients with normal previous results with those with abnormal previous results). Physicians evaluating patients preoperatively could safely substitute the previous test results analyzed in this study for preoperative screening tests if the previous tests are normal and no obvious indication for retesting is present.

Using Transcranial tDCS to test cognitive hypotheses

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Nazbanou Nozari

2014-04-01

Full Text Available Transcranial Direct Current Stimulation (tDCS is used increasingly often for testing cognitive hypotheses. It is, however, often ignored that many assumptions regarding how the neural tissue reacts to stimulation have only been verified in the motor domain. Extrapolating these assumptions to the cognitive domain has a set of unique issues which, if ignored, can lead to incorrect interpretations. In this talk I will review a number of common pitfalls in using tDCS for testing a cognitive hypothesis, and discuss some solutions for better-controlled designs. I will address the following issues: 1- Making an incorrect assumption about the nature of the effect: It is often assumed that anodal stimulation has “excitatory” and cathodal stimulation has “inhibitory” effects. Results are then interpreted in light of this assumption. Obviously, if the assumption is incorrect, the interpretation of the results too will be incorrect. I will discuss how the effects of polarity can change as a function of a number of design parameters, and the dangers of making a priori assumptions about the direction of stimulation effects, especially when employing a new design. 2- Choosing an inappropriate montage: By definition, tDCS requires two electrodes, although we are often only interested in stimulating one brain region. Where the second (reference electrode is placed may not be of theoretical interest to us, but it can have serious consequences for our effects of interest. For one thing the path of the direct current changes as a function of where the reference electrode is placed. This affects the density of the current, as well as the regions that undergo stimulation. Moreover, the region directly under the reference electrode is very likely to be affected by stimulation. Therefore, sometimes the changes in behavior may be due to the unanticipated effects at the reference electrode site, as opposed to the hypothesized effects at the target electrode site

Fruits and wood of Parinari from the early Miocene of Panama and the fossil record of Chrysobalanaceae.

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Jud, Nathan A; Nelson, Chris W; Herrera, Fabiany

2016-02-01

Chrysobalanaceae are woody plants with over 500 species in 20 genera. They are among the most common trees in tropical forests, but a sparse fossil record has limited our ability to test evolutionary and biogeographic hypotheses, and several previous reports of Chrysobalanaceae megafossils are doubtful. We prepared fossil endocarps and wood collected from the lower Miocene beds along the Panama Canal using the cellulose acetate peel technique and examined them using light microscopy. We compared the fossil endocarps with previously published fossils and with fruits from herbarium specimens. We compared the fossil wood with photographs and descriptions of extant species. Parinari endocarps can be distinguished from other genera within Chrysobalanaceae by a suite of features, i.e., thick wall, a secondary septum, seminal cavities lined with dense, woolly trichomes, and two ovate to lingulate basal germination plugs. Fossil endocarps from the Cucaracha, Culebra, and La Boca Formations confirm that Parinari was present in the neotropics by the early Miocene. The earliest unequivocal evidence of crown-group Chrysobalanaceae is late Oligocene-early Miocene, and the genus Parinari was distinct by at least 19 million years ago. Parinari and other Chrysobalanaceae likely reached the neotropics via long-distance dispersal rather than vicariance. The presence of Parinari in the Cucaracha flora supports the interpretation of a riparian, moist tropical forest environment. Parinari was probably a canopy-dominant tree in the Cucaracha forest and took advantage of the local megafauna for seed dispersal. © 2016 Botanical Society of America.

Phylemon 2.0: a suite of web-tools for molecular evolution, phylogenetics, phylogenomics and hypotheses testing.

Science.gov (United States)

Sánchez, Rubén; Serra, François; Tárraga, Joaquín; Medina, Ignacio; Carbonell, José; Pulido, Luis; de María, Alejandro; Capella-Gutíerrez, Salvador; Huerta-Cepas, Jaime; Gabaldón, Toni; Dopazo, Joaquín; Dopazo, Hernán

2011-07-01

Phylemon 2.0 is a new release of the suite of web tools for molecular evolution, phylogenetics, phylogenomics and hypotheses testing. It has been designed as a response to the increasing demand of molecular sequence analyses for experts and non-expert users. Phylemon 2.0 has several unique features that differentiates it from other similar web resources: (i) it offers an integrated environment that enables evolutionary analyses, format conversion, file storage and edition of results; (ii) it suggests further analyses, thereby guiding the users through the web server; and (iii) it allows users to design and save phylogenetic pipelines to be used over multiple genes (phylogenomics). Altogether, Phylemon 2.0 integrates a suite of 30 tools covering sequence alignment reconstruction and trimming; tree reconstruction, visualization and manipulation; and evolutionary hypotheses testing.

Phylemon 2.0: a suite of web-tools for molecular evolution, phylogenetics, phylogenomics and hypotheses testing

Science.gov (United States)

Sánchez, Rubén; Serra, François; Tárraga, Joaquín; Medina, Ignacio; Carbonell, José; Pulido, Luis; de María, Alejandro; Capella-Gutíerrez, Salvador; Huerta-Cepas, Jaime; Gabaldón, Toni; Dopazo, Joaquín; Dopazo, Hernán

2011-01-01

Phylemon 2.0 is a new release of the suite of web tools for molecular evolution, phylogenetics, phylogenomics and hypotheses testing. It has been designed as a response to the increasing demand of molecular sequence analyses for experts and non-expert users. Phylemon 2.0 has several unique features that differentiates it from other similar web resources: (i) it offers an integrated environment that enables evolutionary analyses, format conversion, file storage and edition of results; (ii) it suggests further analyses, thereby guiding the users through the web server; and (iii) it allows users to design and save phylogenetic pipelines to be used over multiple genes (phylogenomics). Altogether, Phylemon 2.0 integrates a suite of 30 tools covering sequence alignment reconstruction and trimming; tree reconstruction, visualization and manipulation; and evolutionary hypotheses testing. PMID:21646336

Five hypotheses concerning the fate of the Singapore issues in the Doha Round

OpenAIRE

Evenett, Simon J.

2017-01-01

At the Cancún Ministerial Conference, the members of the World Trade Organization (WTO) disagreed on whether to launch negotiations on multilateral disciplines concerning the four areas of government policy collectively known as the ‘Singapore issues'. This amounted to a decision not to expand the WTO's boundaries along these dimensions. In this paper, five hypotheses concerning the treatment of the Singapore issues by the WTO's membership are described and assessed. The implications of this ...

Family stress and parental responses to children's negative emotions: tests of the spillover, crossover, and compensatory hypotheses.

Science.gov (United States)

Nelson, Jackie A; O'Brien, Marion; Blankson, A Nayena; Calkins, Susan D; Keane, Susan P

2009-10-01

The relations between 4 sources of family stress (marital dissatisfaction, home chaos, parental depressive symptoms, and job role dissatisfaction) and the emotion socialization practice of mothers' and fathers' responses to children's negative emotions were examined. Participants included 101 couples with 7-year-old children. Dyadic analyses were conducted using the Actor-Partner Interdependence Model and relations were tested in terms of the spillover, crossover, and compensatory hypotheses. Results suggest that measures of family stress relate to supportive and nonsupportive parental responses, though many of these relations differ by parent gender. The results are discussed in terms of the 3 theoretical hypotheses, all of which are supported to some degree depending on the family stressor examined.

A new barrier to dispersal trapped old genetic clines that escaped the Easter Microplate tension zone of the Pacific vent mussels.

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Plouviez, Sophie; Faure, Baptiste; Le Guen, Dominique; Lallier, François H; Bierne, Nicolas; Jollivet, Didier

2013-01-01

Comparative phylogeography of deep-sea hydrothermal vent species has uncovered several genetic breaks between populations inhabiting northern and southern latitudes of the East Pacific Rise. However, the geographic width and position of genetic clines are variable among species. In this report, we further characterize the position and strength of barriers to gene flow between populations of the deep-sea vent mussel Bathymodiolus thermophilus. Eight allozyme loci and DNA sequences of four nuclear genes were added to previously published sequences of the cytochrome c oxidase subunit I gene. Our data confirm the presence of two barriers to gene flow, one located at the Easter Microplate (between 21°33'S and 31°S) recently described as a hybrid zone, and the second positioned between 7°25'S and 14°S with each affecting different loci. Coalescence analysis indicates a single vicariant event at the origin of divergence between clades for all nuclear loci, although the clines are now spatially discordant. We thus hypothesize that the Easter Microplate barrier has recently been relaxed after a long period of isolation and that some genetic clines have escaped the barrier and moved northward where they have subsequently been trapped by a reinforcing barrier to gene flow between 7°25'S and 14°S.

Electroconvulsive therapy's mechanism of action: neuroendocrine hypotheses.

Science.gov (United States)

Haskett, Roger F

2014-06-01

Despite a range of etiological theories since the introduction of electroconvulsive therapy (ECT) more than 75 years ago, its mechanism of action remains poorly understood. The neuroendocrine hypothesis is based on the seizure-related release of hypothalamic hormones into the blood and cerebrospinal fluid and evidence of endocrine dysfunction in many patients with severe mood disorder. The specific effect of ECT was hypothesized to result from the transverse passage of current through the brain with direct stimulation of axial structures including the diencephalon. The prompt release of adrenocorticotropic hormone, cortisol, and prolactin into blood followed ECT with a return to pretreatment baseline levels in several hours. The elevated levels of hormones were absorbed by the cerebrospinal fluid, providing contact with brain cells and central nervous system structures. An apparently specific pattern of ECT-induced hormone changes, limited to prolactin and cortisol, suggested that ECT released a substance with dopaminergic antagonist and antipsychotic properties. As hypothalamic dysfunction is a key finding in endogenomorphic depression and the abnormal endocrine and physiological functions usually normalize with recovery, this led to a search for biological markers that would supplement clinical assessment of diagnosis and treatment response. One of these, the overnight dexamethasone suppression test found that 40% to 50% of melancholic depressed patients had abnormal results, whereas 90% of control patients suppressed normally. This was followed by a period of uncritical overenthusiasm followed by wholesale rejection of the clinical neuroendocrine strategies. Several key methodological issues received inadequate attention, and there have been calls to revisit this topic.

The effect of disgust and fear modeling on children's disgust and fear for animals.

Science.gov (United States)

Askew, Chris; Cakır, Kübra; Põldsam, Liine; Reynolds, Gemma

2014-08-01

Disgust is a protective emotion associated with certain types of animal fears. Given that a primary function of disgust is to protect against harm, increasing children's disgust-related beliefs for animals may affect how threatening they think animals are and their avoidance of them. One way that children's disgust beliefs for animals might change is via vicarious learning: by observing others responding to the animal with disgust. In Experiment 1, children (ages 7-10 years) were presented with images of novel animals together with adult faces expressing disgust. Children's fear beliefs and avoidance preferences increased for these disgust-paired animals compared with unpaired control animals. Experiment 2 used the same procedure and compared disgust vicarious learning with vicarious learning with fear faces. Children's fear beliefs and avoidance preferences for animals again increased as a result of disgust vicarious learning, and animals seen with disgust or fear faces were also rated more disgusting than control animals. The relationship between increased fear beliefs and avoidance preferences for animals was mediated by disgust for the animals. The experiments demonstrate that children can learn to believe that animals are disgusting and threatening after observing an adult responding with disgust toward them. The findings also suggest a bidirectional relationship between fear and disgust with fear-related vicarious learning leading to increased disgust for animals and disgust-related vicarious learning leading to increased fear and avoidance. (c) 2014 APA, all rights reserved.

The Effect of Disgust and Fear Modeling on Children’s Disgust and Fear for Animals

Science.gov (United States)

2014-01-01

Disgust is a protective emotion associated with certain types of animal fears. Given that a primary function of disgust is to protect against harm, increasing children’s disgust-related beliefs for animals may affect how threatening they think animals are and their avoidance of them. One way that children’s disgust beliefs for animals might change is via vicarious learning: by observing others responding to the animal with disgust. In Experiment 1, children (ages 7–10 years) were presented with images of novel animals together with adult faces expressing disgust. Children’s fear beliefs and avoidance preferences increased for these disgust-paired animals compared with unpaired control animals. Experiment 2 used the same procedure and compared disgust vicarious learning with vicarious learning with fear faces. Children’s fear beliefs and avoidance preferences for animals again increased as a result of disgust vicarious learning, and animals seen with disgust or fear faces were also rated more disgusting than control animals. The relationship between increased fear beliefs and avoidance preferences for animals was mediated by disgust for the animals. The experiments demonstrate that children can learn to believe that animals are disgusting and threatening after observing an adult responding with disgust toward them. The findings also suggest a bidirectional relationship between fear and disgust with fear-related vicarious learning leading to increased disgust for animals and disgust-related vicarious learning leading to increased fear and avoidance. PMID:24955571

Statistical analysis of hypotheses on the cointegrating relations in the I(2) model

DEFF Research Database (Denmark)

Johansen, Søren

2006-01-01

The cointegrated vector autoregressive model for I(2) variables is a non-linear parametric restriction on the linear I(2) regression model for variables of order I(0), I(1) and I(2). In this paper we discuss non-linear submodels given by smooth parametrizations. We give conditions on the parametr......) and the reformulation is applied to show that some hypotheses on the cointegrating coefficients in the cointegrated I(2) model give asymptotic ¿² inference....

How and when do expert emergency physicians generate and evaluate diagnostic hypotheses? A qualitative study using head-mounted video cued-recall interviews.

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Pelaccia, Thierry; Tardif, Jacques; Triby, Emmanuel; Ammirati, Christine; Bertrand, Catherine; Dory, Valérie; Charlin, Bernard

2014-12-01

The ability to make a diagnosis is a crucial skill in emergency medicine. Little is known about the way emergency physicians reach a diagnosis. This study aims to identify how and when, during the initial patient examination, emergency physicians generate and evaluate diagnostic hypotheses. We carried out a qualitative research project based on semistructured interviews with emergency physicians. The interviews concerned management of an emergency situation during routine medical practice. They were associated with viewing the video recording of emergency situations filmed in an "own-point-of-view" perspective. The emergency physicians generated an average of 5 diagnostic hypotheses. Most of these hypotheses were generated before meeting the patient or within the first 5 minutes of the meeting. The hypotheses were then rank ordered within the context of a verification procedure based on identifying key information. These tasks were usually accomplished without conscious effort. No hypothesis was completely confirmed or refuted until the results of investigations were available. The generation and rank ordering of diagnostic hypotheses is based on the activation of cognitive processes, enabling expert emergency physicians to process environmental information and link it to past experiences. The physicians seemed to strive to avoid the risk of error by remaining aware of the possibility of alternative hypotheses as long as they did not have the results of investigations. Understanding the diagnostic process used by emergency physicians provides interesting ideas for training residents in a specialty in which the prevalence of reasoning errors leading to incorrect diagnoses is high. Copyright © 2014 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.

Mesozoic fossils (>145 Mya) suggest the antiquity of the subgenera of Daphnia and their coevolution with chaoborid predators.

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Kotov, Alexey A; Taylor, Derek J

2011-05-19

The timescale of the origins of Daphnia O. F. Mueller (Crustacea: Cladocera) remains controversial. The origin of the two main subgenera has been associated with the breakup of the supercontinent Pangaea. This vicariance hypothesis is supported by reciprocal monophyly, present day associations with the former Gondwanaland and Laurasia regions, and mitochondrial DNA divergence estimates. However, previous multilocus nuclear DNA sequence divergence estimates at Pangaea. We examined new and existing cladoceran fossils from a Mesozoic Mongolian site, in hopes of gaining insights into the timescale of the evolution of Daphnia. We describe new fossils of ephippia from the Khotont site in Mongolia associated with the Jurassic-Cretaceous boundary (about 145 MYA) that are morphologically similar to several modern genera of the family Daphniidae, including the two major subgenera of Daphnia, i.e., Daphnia s. str. and Ctenodaphnia. The daphniid fossils co-occurred with fossils of the predaceous phantom midge (Chaoboridae). Our findings indicate that the main subgenera of Daphnia are likely much older than previously known from fossils (at least 100 MY older) or from nuclear DNA estimates of divergence. The results showing co-occurrence of the main subgenera far from the presumed Laurasia/Gondwanaland dispersal barrier shortly after formation suggests that vicariance from the breakup of Pangaea is an unlikely explanation for the origin of the main subgenera. The fossil impressions also reveal that the coevolution of a dipteran predator (Chaoboridae) with the subgenus Daphnia is much older than previously known -- since the Mesozoic.

Masticatory-stress hypotheses and the supraorbital region of primates.

Science.gov (United States)

Hylander, W L; Picq, P G; Johnson, K R

1991-09-01

The purpose of this study is to test various masticatory-stress hypotheses about the evolution and function of well-developed browridges of higher primates. This was done by measuring and analyzing patterns of in vivo bone strain recorded from three-element rosette strain gages bonded to the supraorbital region and to other portions of the bony face of Macaca fascicularis and Papio anubis during mastication and incision. The magnitude and direction of the principal strains recorded support Endo's hypothesis that the supraorbital region during mastication and incision is bent in the frontal plane (Endo, 1966). Our data do not, however, support his hypothesis that the supraorbital region is bent more during incision than during mastication. The data also demonstrate that overall levels of supraorbital strain are not larger in more prognathic subjects. Most importantly, the data indicate that the supraorbital region of nonhuman catarrhines is strained very little during mastication and incision. This indicates that there is much more supraorbital bone than is necessary both to counter masticatory loads and to provide an adequate safety factor to failure for these loads. This in turn suggests that the macaque and baboon browridges can be considerably reduced in size and still maintain these required structural characteristics. Thus, our experiments provide no support whatsoever for those hypotheses that directly link browridge morphology to masticatory stress (cf. Endo, 1966; Russell, 1983, 1985). A recent review of Endo's original work indicates that this latter statement is also true for humans (Picq and Hylander, 1989). We conclude, therefore, that there is no good reason to believe that enlarged browridges in living and/or fossil primates are structural adaptations to counter intense masticatory forces. The evolution of browridge morphology in primates is best explained on the basis of factors related to the position of the brain relative to the orbits (Moss and

The Association between Relational Aggression and Perceived Popularity in Early Adolescence: A Test of Competing Hypotheses

Science.gov (United States)

Gangel, Meghan J.; Keane, Susan P.; Calkins, Susan D.; Shanahan, Lilly; O'Brien, Marion

2017-01-01

This study examined two competing hypotheses regarding the moderators of the association between relational aggression and peer status in early adolescence. The "mitigation relational aggression" hypothesis examined whether positive social behaviors reduced the negative effects of relational aggression, thus amplifying the association…

Coopersmith Self-Esteem: Two Different Hypothesized Factor Models--Both Acceptable for the Same Data Structure.

Science.gov (United States)

Hofmann, Rich; Sherman, Larry

Using data from 135 sixth-, seventh-, and eighth-graders between 11 and 15 years old attending a middle school in a suburban Southwest Ohio school district, two hypothesized models of the factor structures for the Coopersmith Self-Esteem Inventory were tested. One model represents the original Coopersmith factor structure, and the other model is…

Observing tutorial dialogues collaboratively: insights about human tutoring effectiveness from vicarious learning.

Science.gov (United States)

Chi, Michelene T H; Roy, Marguerite; Hausmann, Robert G M

2008-03-01

The goals of this study are to evaluate a relatively novel learning environment, as well as to seek greater understanding of why human tutoring is so effective. This alternative learning environment consists of pairs of students collaboratively observing a videotape of another student being tutored. Comparing this collaboratively observing environment to four other instructional methods-one-on-one human tutoring, observing tutoring individually, collaborating without observing, and studying alone-the results showed that students learned to solve physics problems just as effectively from observing tutoring collaboratively as the tutees who were being tutored individually. We explain the effectiveness of this learning environment by postulating that such a situation encourages learners to become active and constructive observers through interactions with a peer. In essence, collaboratively observing combines the benefit of tutoring with the benefit of collaborating. The learning outcomes of the tutees and the collaborative observers, along with the tutoring dialogues, were used to further evaluate three hypotheses explaining why human tutoring is an effective learning method. Detailed analyses of the protocols at several grain sizes suggest that tutoring is effective when tutees are independently or jointly constructing knowledge: with the tutor, but not when the tutor independently conveys knowledge. 2008 Cognitive Science Society, Inc.

Family Stress and Parental Responses to Children’s Negative Emotions: Tests of the Spillover, Crossover, and Compensatory Hypotheses

Science.gov (United States)

Nelson, Jackie A.; O’Brien, Marion; Blankson, A. Nayena; Calkins, Susan D.; Keane, Susan P.

2010-01-01

The relations between 4 sources of family stress (marital dissatisfaction, home chaos, parental depressive symptoms, and job role dissatisfaction) and the emotion socialization practice of mothers’ and fathers’ responses to children’s negative emotions were examined. Participants included 101 couples with 7-year-old children. Dyadic analyses were conducted using the Actor–Partner Interdependence Model and relations were tested in terms of the spillover, crossover, and compensatory hypotheses. Results suggest that measures of family stress relate to supportive and nonsupportive parental responses, though many of these relations differ by parent gender. The results are discussed in terms of the 3 theoretical hypotheses, all of which are supported to some degree depending on the family stressor examined. PMID:19803603

Enabling the development of student teacher professional identity ...

African Journals Online (AJOL)

This paper explores the views of student teachers who were provided vicarious learning opportunities during an educational excursion, and how the learning enabled them to develop their teacher professional identity. This qualitative research study, using a social-constructivist lens highlights how vicarious learning ...

Reactor Core Coolability Analysis during Hypothesized Severe Accidents of OPR1000

International Nuclear Information System (INIS)

Lee, Yongjae; Seo, Seungwon; Kim, Sung Joong; Ha, Kwang Soon; Kim, Hwan-Yeol

2014-01-01

Assessment of the safety features over the hypothesized severe accidents may be performed experimentally or numerically. Due to the considerable time and expenditures, experimental assessment is implemented only to the limited cases. Therefore numerical assessment has played a major role in revisiting severe accident analysis of the existing or newly designed power plants. Computer codes for the numerical analysis of severe accidents are categorized as the fast running integral code and detailed code. Fast running integral codes are characterized by a well-balanced combination of detailed and simplified models for the simulation of the relevant phenomena within an NPP in the case of a severe accident. MAAP, MELCOR and ASTEC belong to the examples of fast running integral codes. Detailed code is to model as far as possible all relevant phenomena in detail by mechanistic models. The examples of detailed code is SCDAP/RELAP5. Using the MELCOR, Carbajo. investigated sensitivity studies of Station Black Out (SBO) using the MELCOR for Peach Bottom BWR. Park et al. conduct regulatory research of the PWR severe accident. Ahn et al. research sensitivity analysis of the severe accident for APR1400 with MELCOR 1.8.4. Lee et al. investigated RCS depressurization strategy and developed a core coolability map for independent scenarios of Small Break Loss-of-Coolant Accident (SBLOCA), SBO, and Total Loss of Feed Water (TLOFW). In this study, three initiating cases were selected, which are SBLOCA without SI, SBO, and TLOFW. The initiating cases exhibit the highest probability of transitioning into core damage according to PSA 1 of OPR 1000. The objective of this study is to investigate the reactor core coolability during hypothesized severe accidents of OPR1000. As a representative indicator, we have employed Jakob number and developed JaCET and JaMCT using the MELCOR simulation. Although the RCS pressures for the respective accident scenarios were different, the JaMCT and Ja

Evolution of microgastropods (Ellobioidea, Carychiidae): integrating taxonomic, phylogenetic and evolutionary hypotheses

Science.gov (United States)

2013-01-01

Background Current biodiversity patterns are considered largely the result of past climatic and tectonic changes. In an integrative approach, we combine taxonomic and phylogenetic hypotheses to analyze temporal and geographic diversification of epigean (Carychium) and subterranean (Zospeum) evolutionary lineages in Carychiidae (Eupulmonata, Ellobioidea). We explicitly test three hypotheses: 1) morphospecies encompass unrecognized evolutionary lineages, 2) limited dispersal results in a close genetic relationship of geographical proximally distributed taxa and 3) major climatic and tectonic events had an impact on lineage diversification within Carychiidae. Results Initial morphospecies assignments were investigated by different molecular delimitation approaches (threshold, ABGD, GMYC and SP). Despite a conservative delimitation strategy, carychiid morphospecies comprise a great number of unrecognized evolutionary lineages. We attribute this phenomenon to historic underestimation of morphological stasis and phenotypic variability amongst lineages. The first molecular phylogenetic hypothesis for the Carychiidae (based on COI, 16S and H3) reveals Carychium and Zospeum to be reciprocally monophyletic. Geographical proximally distributed lineages are often closely related. The temporal diversification of Carychiidae is best described by a constant rate model of diversification. The evolution of Carychiidae is characterized by relatively few (long distance) colonization events. We find support for an Asian origin of Carychium. Zospeum may have arrived in Europe before extant members of Carychium. Distantly related Carychium clades inhabit a wide spectrum of the available bioclimatic niche and demonstrate considerable niche overlap. Conclusions Carychiid taxonomy is in dire need of revision. An inferred wide distribution and variable phenotype suggest underestimated diversity in Zospeum. Several Carychium morphospecies are results of past taxonomic lumping. By collecting

[The evolution of plant life span: facts and hypotheses].

Science.gov (United States)

2006-01-01

There are two different views on the evolution of life forms in Cormophyta: from woody plants to herbaceous ones or in opposite direction - from herbs to trees. In accordance with these views it is supposed that life span in plants changed in the course of evolution from many years (perennials) to few years (annuals, biennials), or went in reverse - from few years to many years. The author discusses the problems of senescence and longevity in Cormophyta in the context of various hypotheses of ageing (programmed death theory, mutation accumulation, antagonistic pleiotropy, disposable soma, genes of ageing, genes of longevity). Special attention is given to bio-morphological aspects of longevity and cases of non-ageing plants ("negative senescence", "potential immortality"). It is proposed to distinguish seven models of simple ontogenesis in Cormophyta that can exemplify the diversity of mechanisms of ageing and longevity. The evolution of life span in plants is considered as an indirect result of natural selection of other characteristics of organisms or as a consequence of fixation of modifications (episelectional evolution). It seems that short life span could emerge several times during evolution of one group of plants, thus favoring its adaptive radiation.

H-convergence for quasi-linear elliptic equations under natural hypotheses on the correctors

International Nuclear Information System (INIS)

Bensoussan, A.; Boccardo, L.; Dall'Aglio, A.; Murat, F.

1995-01-01

In this paper we study the behavior of the solutions of quasi-linear Dirichlet problems when the principal parts H-converge and when the lower order terms have quadratic growth with respect to the gradient. We show that the limit problem consists of a principal part which is the H-limit of the principal parts and of the lower order term which is constructed from the corresponding terms by using a linear corrector result. We assume only natural hypotheses on the correctors (i.e. L 2 equi-integrability and not L ∞ boundedness). (author)

Geophysical Evolution of Ch Asteroids and Testable Hypotheses for Future Missions

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Castillo, J. C.

2017-12-01

The main population of asteroids related to meteorites in the collections remains to be explored in situ. Ch asteroids are the only midsized asteroids that display a signature of hydration (besides Pallas) and the spectral connection between Ch asteroids and CM chondrites suggests that the former represent potential parent bodies for the latter. This class of asteroids is particularly interesting because it hosts many objects 100-200 km in size, which are believed to belong to a primordial population of planetesimals. This presentation will explore multiple evolution pathways for Ch-asteroids leading to possible hypotheses on the geological, petrological, and geophysical properties that a disrupted parent body would present to a future mission. This work is being carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA.

Evaluating Hypotheses of Plant Species Invasions on Mediterranean Islands: Inverse Patterns between Alien and Endemic Species

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Alexander Bjarnason

2017-08-01

Full Text Available Invasive alien species cause major changes to ecosystem functioning and patterns of biodiversity, and the main factors involved in invasion success remain contested. Using the Mediterranean island of Crete, Greece as a case study, we suggest a framework for analyzing spatial data of alien species distributions, based on environmental predictors, aiming to gain an understanding of their spatial patterns and spread. Mediterranean islands are under strong ecological pressure from invading species due to their restricted size and increased human impact. Four hypotheses of invasibility, the “propagule pressure hypothesis” (H1, “biotic resistance hypothesis vs. acceptance hypothesis” (H2, “disturbance-mediated hypothesis” (H3, and “environmental heterogeneity hypothesis” (H4 were tested. Using data from alien, native, and endemic vascular plant species, the propagule pressure, biotic resistance vs. acceptance, disturbance-mediated, and environmental heterogeneity hypotheses were tested with Generalized Additive Modeling (GAM of 39 models. Based on model selection, the optimal model includes the positive covariates of native species richness, the negative covariates of endemic species richness, and land area. Variance partitioning between the four hypotheses indicated that the biotic resistance vs. acceptance hypothesis explained the vast majority of the total variance. These results show that areas of high species richness have greater invasibility and support the acceptance hypothesis and “rich-get-richer” distribution of alien species. The negative correlation between alien and endemic species appears to be predominantly driven by altitude, with fewer alien and more endemic species at greater altitudes, and habitat richness. The negative relationship between alien and endemic species richness provides potential for understanding patterns of endemic and alien species on islands, contributing to more effective conservation

Positive deviance control-case life history: a method to develop grounded hypotheses about successful long-term avoidance of infection

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Sandoval Milagros

2008-03-01

Full Text Available Abstract Background Prevalence rates for long-term injection drug users in some localities surpass 60% for HIV and 80% for HCV. We describe methods for developing grounded hypotheses about how some injectors avoid infection with either virus. Methods Subjects: 25 drug injectors who have injected drugs 8 – 15 years in New York City. 17 remain without antibody to either HIV or HCV; 3 are double-positives; and 5 are positive for HCV but not HIV. "Staying Safe" methodology compares serostatus groups using detailed biographical timelines and narratives; and information about how subjects maintain access to physical resources and social support; their strategies and tactics to remain safe; how they handle problems of addiction and demands by drug dealers and other drug users; and how their behaviors and strategies do or do not become socially-embedded practices. Grounded theory and life-history analysis techniques compare and contrast doubly-uninfected with those infected with both viruses or only with HCV. Results Themes and initial hypotheses emerging from analyses included two master hypotheses that, if confirmed, should help shape preventive interventions: 1 Staying uninfected is not simply a question of social structure or social position. It involves agency by drug injectors, including sustained hard work and adaptation to changing circumstances. 2 Multiple intentionalities contribute to remaining uninfected. These conscious goals include balancing one's need for drugs and one's income; developing ways to avoid drug withdrawal sickness; avoiding situations where other drug users importune you to share drugs; and avoiding HIV (and perhaps HCV infection. Thus, focusing on a single goal in prevention might be sub-optimal. Other hypotheses specify mechanisms of enacting these intentionalities. One example is finding ways to avoid extreme social ostracism. Conclusion We have identified strategies and tactics that some doubly-uninfected IDUs have

Testing multiple statistical hypotheses resulted in spurious associations: a study of astrological signs and health.

Science.gov (United States)

Austin, Peter C; Mamdani, Muhammad M; Juurlink, David N; Hux, Janet E

2006-09-01

To illustrate how multiple hypotheses testing can produce associations with no clinical plausibility. We conducted a study of all 10,674,945 residents of Ontario aged between 18 and 100 years in 2000. Residents were randomly assigned to equally sized derivation and validation cohorts and classified according to their astrological sign. Using the derivation cohort, we searched through 223 of the most common diagnoses for hospitalization until we identified two for which subjects born under one astrological sign had a significantly higher probability of hospitalization compared to subjects born under the remaining signs combined (P<0.05). We tested these 24 associations in the independent validation cohort. Residents born under Leo had a higher probability of gastrointestinal hemorrhage (P=0.0447), while Sagittarians had a higher probability of humerus fracture (P=0.0123) compared to all other signs combined. After adjusting the significance level to account for multiple comparisons, none of the identified associations remained significant in either the derivation or validation cohort. Our analyses illustrate how the testing of multiple, non-prespecified hypotheses increases the likelihood of detecting implausible associations. Our findings have important implications for the analysis and interpretation of clinical studies.

Historical biogeographic analysis of the family Fanniidae (Díptera: Calyptratae, with special reference to the austral species of the genus Fannia (Diptera: Fanniidae using dispersal-vicariance analysis Análisis biogeográfico histórico de la familia Fanniidae (Diptera: Calyptratae, con referencia especial a las especies australes del genero Fannia (Diptera: Fanniidae usando análisis de dipersion-vicarianza

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M. CECILIA DOMÍNGUEZ

2011-03-01

Full Text Available The purpose of this study was to achieve a hypothesis explaining the biogeographical history of the family Fanniidae, especially that of the species from Patagonia, the Neotropics, Australia, and New Zealand. We used "dispersal-vicariance analysis" (DIVA, an event-based parsimony method, to analyze the most parsimonious phylogenetic hypothesis for the family, obtained by Domínguez & Roig-Juñent (2008. The analysis resulted in 32800 alternative equally optimal reconstructions that indicate that the ancestor of the Fanniidae was widely distributed across different regions of the world, which along with the subsequent separation of two clades that correspond to the Laurasic and Gondwanan Landmasses allow the proposal of an older age than in previous hypothesis (Late Jurassic or early Cretaceous times instead of upper Cretaceous and a Pangeic origin for the Fanniidae. The northern hemisphere species of Fanniidae included in this study highlight the difficulty that arises when analysing with DIVA a tree with a large amount of paralogy or redundant distributions, as illustrated here with several examples. The southern hemisphere species of Fanniidae indicate a clear pattern of vicariance and dispersal consistent with the rupture of Gondwana.El propósito de este estudio fue el de obtener una hipótesis que explique la historia biogeográfica de la familia Fanniidae, especialmente la de las especies de las regiones Patagónica, Neotropical, Australiana y Neozelandesa. Se utilizó el método de "dispersión y vicarianza" (DIVA, el cual es un método de parsimonia basado en eventos para analizar el árbol filogenético más parsimonioso obtenido por Domínguez & Roig-Juñent (2008. El análisis resultó en 32800 reconstrucciones alternativas igualmente óptimas que indican que el ancestro de Fanniidae estaba ampliamente distribuido en distintas regiones del mundo, lo cual junto con la subsiguiente separación de dos clados que corresponderían a los

Improving the Development of Student's Research Questions and Hypotheses in an Introductory Business Research Methods Course

Science.gov (United States)

Strangman, Lauria; Knowles, Elizabeth

2012-01-01

In an introductory research methods course, students often develop research questions and hypotheses that are vague or confusing, do not contain measurable concepts, and are too narrow in scope or vision. Because of this, the final research projects often fail to provide useful information or address the overall research problem. A Lesson Study…

One year after the Zika virus outbreak in Brazil: from hypotheses to evidence

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Carlos Alexandre Antunes de Brito

Full Text Available Abstract Zika virusis an arbovirus of the Flaviviridae family with two major strains, an Asian and an African strain. The main vectors involved in the transmission of Zika virus are the Aedes aegypti and Aedes albopictus mosquitoes. Despite its identification, discovered in 1947 in the Zika forest in Uganda, only isolated and sporadic occurrences of human infection were reported within a largely asymptomatic proportion of individuals. The first reported outbreak occurred in 2007 in the Yap Island, which belongs to the Federated States of Micronesia in the Pacific Ocean, and in French Polynesia, where high attack rates occurred and the first cases of associated Guillain-Barré syndrome were reported. From November 2014 to early 2015, the Northeast states of Brazil reported the first outbreaks of Zika virus infection, with laboratory confirmation of Zika virus circulation in April 2015. In the second quarter of 2015, the association between Zika virus infection and neurological symptoms was confirmed in adults. Moreover, in October 2015 a novel suspicion was raised based on clinical and epidemiological observations: that an association between Zika virus infection and neonatal microcephaly may exist. A year after the first reports on Zika virus in Brazil, many hypotheses and much evidence on the patterns of involvement of the disease and its complications have been produced, both in this country and others; other hypotheses still need to be clarified. This review is a synthesis of a new chapter in the history of medicine; it outlines the main results produced.

Can manipulations of cognitive load be used to test evolutionary hypotheses?

Science.gov (United States)

Barrett, H Clark; Frederick, David A; Haselton, Martie G; Kurzban, Robert

2006-09-01

D. DeSteno, M. Y. Bartlett, J. Braverman, and P. Salovey proposed that if sex-differentiated responses to infidelity are evolved, then they should be automatic, and therefore cognitive load should not attenuate them. DeSteno et al. found smaller sex differences in response to sexual versus emotional infidelity among participants under cognitive load, an effect interpreted as evidence against the evolutionary hypothesis. This logic is faulty. Cognitive load probably affects mechanisms involved in simulating infidelity experiences, thus seriously challenging the usefulness of cognitive load manipulations in testing hypotheses involving simulation. The method also entails the assumption that evolved jealousy mechanisms are necessarily automatic, an assumption not supported by theory or evidence. Regardless of how the jealousy debate is eventually settled, cognitive load manipulations cannot rule out the operation of evolved mechanisms. ((c) 2006 APA, all rights reserved).

Plant ecosystem responses to rising atmospheric CO2: applying a "two-timing" approach to assess alternative hypotheses for mechanisms of nutrient limitation

Science.gov (United States)

Medlyn, B.; Jiang, M.; Zaehle, S.

2017-12-01

There is now ample experimental evidence that the response of terrestrial vegetation to rising atmospheric CO2 concentration is modified by soil nutrient availability. How to represent nutrient cycling processes is thus a key consideration for vegetation models. We have previously used model intercomparison to demonstrate that models incorporating different assumptions predict very different responses at Free-Air CO2 Enrichment experiments. Careful examination of model outputs has provided some insight into the reasons for the different model outcomes, but it is difficult to attribute outcomes to specific assumptions. Here we investigate the impact of individual assumptions in a generic plant carbon-nutrient cycling model. The G'DAY (Generic Decomposition And Yield) model is modified to incorporate alternative hypotheses for nutrient cycling. We analyse the impact of these assumptions in the model using a simple analytical approach known as "two-timing". This analysis identifies the quasi-equilibrium behaviour of the model at the time scales of the component pools. The analysis provides a useful mathematical framework for probing model behaviour and identifying the most critical assumptions for experimental study.

Pickles and ice cream! Food cravings in pregnancy: hypotheses, preliminary evidence, and directions for future research

Science.gov (United States)

Orloff, Natalia C.; Hormes, Julia M.

2014-01-01

Women in the United States experience an increase in food cravings at two specific times during their life, (1) perimenstrually and (2) prenatally. The prevalence of excess gestational weight gain (GWG) is a growing concern due to its association with adverse health outcomes in both mothers and children. To the extent that prenatal food cravings may be a determinant of energy intake in pregnancy, a better understanding of craving etiology could be crucial in addressing the issue of excessive GWG. This paper reviews the available literature to corroborate and/or dispute some of the most commonly accepted hypotheses regarding the causes of food cravings during pregnancy, including a role of (1) hormonal changes, (2) nutritional deficits, (3) pharmacologically active ingredients in the desired foods, and (4) cultural and psychosocial factors. An existing model of perimenstrual chocolate craving etiology serves to structure the discussion of these hypotheses. The main hypotheses discussed receive little support, with the notable exception of a postulated role of cultural and psychosocial factors. The presence of cravings during pregnancy is a common phenomenon across different cultures, but the types of foods desired and the adverse impact of cravings on health may be culture-specific. Various psychosocial factors appear to correlate with excess GWG, including the presence of restrained eating. Findings strongly suggest that more research be conducted in this area. We propose that future investigations fall into one of the four following categories: (1) validation of food craving and eating-related measures specifically in pregnant populations, (2) use of ecological momentary assessment to obtain real time data on cravings during pregnancy, (3) implementation of longitudinal studies to address causality between eating disorder symptoms, food cravings, and GWG, and (4) development of interventions to ensure proper prenatal nutrition and prevent excess GWG. PMID:25295023

Pickles and Ice Cream! Food Cravings in Pregnancy: Hypotheses, Preliminary Evidence, and Directions for Future Research

Directory of Open Access Journals (Sweden)

Natalia C. Orloff

2014-09-01

Full Text Available Women in the United States experience an increase in food cravings at two specific times during their life, 1 perimenstrually and 2 prenatally. The prevalence of excess gestational weight gain (GWG is a growing concern due to its association with adverse health outcomes in both mothers and children. To the extent that prenatal food cravings may be a determinant of energy intake in pregnancy, a better understanding of craving etiology could be crucial in addressing the issue of excessive GWG. This paper reviews the available literature to corroborate and/or dispute some of the most commonly accepted hypotheses regarding the causes of food cravings during pregnancy, including a role of 1 hormonal changes, 2 nutritional deficits, 3 pharmacologically active ingredients in the desired foods, and 4 cultural and psychosocial factors. An existing model of perimenstrual chocolate craving etiology serves to structure the discussion of these hypotheses. The main hypotheses discussed receive little support, with the notable exception of a postulated role of cultural and psychosocial factors. The presence of cravings during pregnancy is a common phenomenon across different cultures, but the types of foods desired and the adverse impact of cravings on health may be culture-specific. Various psychosocial factors appear to correlate with excess GWG, including the presence of restrained eating. Findings strongly suggest that more research be conducted in this area. We propose that future investigations fall into one of the four following categories: 1 validation of food craving and eating-related measures specifically in pregnant populations, 2 use of ecological momentary assessment to obtain real time data on cravings during pregnancy, 3 implementation of longitudinal studies to address causality between eating disorder symptoms, food cravings, and gestational weight gain, and 4 development of interventions to ensure proper prenatal nutrition and prevent excess

The roles of ingroup identification and outgroup entitativity in intergroup retribution.

Science.gov (United States)

Stenstrom, Douglas M; Lickel, Brian; Denson, Thomas F; Miller, Norman

2008-11-01

A new aspect of intergroup conflict was investigated- vicarious retribution-in which neither the agent of retribution nor the target of retribution are directly involved in the initial intergroup provocation. The underlying processes involved in vicarious intergroup retribution were tested correlationally (Study 1) and experimentally (Study 2). Both ingroup identification and outgroup entitativity predict the degree of vicarious retribution. In both studies, there was evidence of motivated cognition, specifically that highly identified individuals perceived the outgroup as higher in entitativity than individuals low in identification. Structural equation modeling demonstrated that part of the effect of identification on retribution against the outgroup was mediated through perceptions of entitativity.

Fear of knowledge: Clinical hypotheses in diagnostic and prognostic reasoning.

Science.gov (United States)

Chiffi, Daniele; Zanotti, Renzo

2017-10-01

Patients are interested in receiving accurate diagnostic and prognostic information. Models and reasoning about diagnoses have been extensively investigated from a foundational perspective; however, for all its importance, prognosis has yet to receive a comparable degree of philosophical and methodological attention, and this may be due to the difficulties inherent in accurate prognostics. In the light of these considerations, we discuss a considerable body of critical thinking on the topic of prognostication and its strict relations with diagnostic reasoning, pointing out the distinction between nosographic and pathophysiological types of diagnosis and prognosis, underlying the importance of the explication and explanation processes. We then distinguish between various forms of hypothetical reasoning applied to reach diagnostic and prognostic judgments, comparing them with specific forms of abductive reasoning. The main thesis is that creative abduction regarding clinical hypotheses in diagnostic process is very unlikely to occur, whereas this seems to be often the case for prognostic judgments. The reasons behind this distinction are due to the different types of uncertainty involved in diagnostic and prognostic judgments. © 2016 John Wiley & Sons, Ltd.

Combining soft decision algorithms and scale-sequential hypotheses pruning for object recognition

Energy Technology Data Exchange (ETDEWEB)

Kumar, V.P.; Manolakos, E.S. [Northeastern Univ., Boston, MA (United States)

1996-12-31

This paper describes a system that exploits the synergy of Hierarchical Mixture Density (HMD) estimation with multiresolution decomposition based hypothesis pruning to perform efficiently joint segmentation and labeling of partially occluded objects in images. First we present the overall structure of the HMD estimation algorithm in the form of a recurrent neural network which generates the posterior probabilities of the various hypotheses associated with the image. Then in order to reduce the large memory and computation requirement we propose a hypothesis pruning scheme making use of the orthonormal discrete wavelet transform for dimensionality reduction. We provide an intuitive justification for the validity of this scheme and present experimental results and performance analysis on real and synthetic images to verify our claims.

Age and motives for volunteering: testing hypotheses derived from socioemotional selectivity theory.

Science.gov (United States)

Okun, Morris A; Schultz, Amy

2003-06-01

Following a meta-analysis of the relations between age and volunteer motives (career, understanding, enhancement, protective, making friends, social, and values), the authors tested hypotheses derived from socioemotional selectivity theory regarding the effects of age on these volunteer motives. The Volunteer Functions Inventory was completed by 523 volunteers from 2 affiliates of the International Habitat for Humanity. Multiple regression analyses revealed, as predicted, that as age increases, career and understanding volunteer motivation decrease and social volunteer motivation increases. Contrary to expectations, age did not contribute to the prediction of enhancement, protective, and values volunteer motivations and the relation between age and making friends volunteer motivation was nonlinear. The results were discussed in the context of age-differential and age-similarity perspectives on volunteer motivation.

Previous PICC Placement May Be Associated With Catheter-Related Infections in Hemodialysis Patients

International Nuclear Information System (INIS)

Butler, Philip J.; Sood, Shreya; Mojibian, Hamid; Tal, Michael G.

2011-01-01

Background: Catheter-related infections (CRIs) are a significant source of morbidity and mortality in hemodialysis patients. The identification of novel, modifiable risk factors for CRIs may lead to improved outcomes in this population. Peripherally inserted central catheters (PICCs) have been hypothesized to compromise vascular access due to vascular damage and venous thrombosis, whereas venous thrombosis has been linked to the development of CRIs. Here we examine the association between PICC placement and CRIs. Methods: A retrospective review was performed of all chronic hemodialysis catheter placements and exchanges performed at a large university hospital from September 2003 to September 2008. History of PICC line use was determined by examining hospital radiologic records from December 1993 to September 2008. Catheter-related complications were assessed and correlated with PICC line history. Results: One hundred eighty-five patients with 713 chronic tunneled hemodialysis catheter placements were identified. Thirty-eight of those patients (20.5%) had a history of PICC placement; these patients were more likely to have CRIs (odds ratio = 2.46, 95% confidence interval = 1.71–3.53, p < .001) compared with patients without a history of PICC placement. There was no difference between the two groups in age or number of catheters placed. Conclusion: Previous PICC placement may be associated with catheter-related infections in hemodialysis patients.

Do Job Demands of Chinese Manufacturing Employees Predict Positive or Negative Outcomes? A Test of Competing Hypotheses.

Science.gov (United States)

Cheung, Janelle H; Sinclair, Robert R; Shi, Junqi; Wang, Mo

2015-12-01

Karasek's job demands-control (JDC) model posits that job control can buffer against the harmful effects of demands experienced by employees. A large volume of JDC research has obtained support for the main effects of demands and control, but not the interactive effects. Recent research on the challenge-hindrance stressors framework, however, found that work stressors may not always be deleterious, suggesting alternative hypotheses about the effects of demands and control. The present study therefore examined competing hypotheses concerning the effects of job demands on occupational health outcomes. Using a sample of 316 employees in a Chinese manufacturing company, we found that, consistent with the challenge-hindrance framework, production demands were challenge stressors associated with favourable outcomes (i.e. job satisfaction and psychological well-being). In addition, results showed that the interactive role of job control depended on the nature of outcome variables. Future recommendations and implications of findings are discussed. Copyright © 2014 John Wiley & Sons, Ltd.

Deterrence's Element of Sanction Certainty: Friendships, Vicarious Experiences, and Underage Alcohol Use.

Science.gov (United States)

Mowen, Thomas J; Boman, John H

2018-01-09

Underage drinking remains a pressing issue on college campuses across the United States. Though the most common form of addressing underage alcohol use on campuses is through deterrence-based policies, evidence suggests deterrence-based methods are ineffective and may produce negative outcomes. Using dyadic data, the objective of this study is to use a friendship-informed perspective on deterrence theory to examine how an individual's and his/her friend's perceptions of sanction certainty relate to self-reported underage alcohol use. Using multilevel mixed models which fall under the actor-partner interdependence modeling class, results demonstrate that respondents who perceive high levels of sanction certainty drink and heavily use alcohol more frequently than those who perceive low levels of sanction certainty. Additionally, those who have friends who perceive high levels of sanction certainty tend to drink at young ages significantly more frequently and in more dangerous patterns than those who have friends who perceive a low sanction certainty. The dyad members' levels of sanction certainty do not interact in relation to alcohol use. The significant relationships of the friends' sanction certainty support the notion of friendship-based deterrence. However, the consistent positive direction of all sanction certainty measures is the opposite of what deterrence theory hypothesizes. As such, it appears that deterrence is not only ineffective at stopping underage alcohol use on college campuses, but may be harmful due to increased rates of both drinking and high-risk drinking.

[Co-occurrence of anxiety and autism. The social error and allostatic load hypotheses].

Science.gov (United States)

Paula-Perez, Isabel

2013-02-22

INTRODUCTION. The concept of comorbidity in neurodevelopmental disorders like autism is sometimes ambiguous. The co-occurrence of anxiety and autism is clinically significant, yet it is not always easy to determine whether it is a 'real' comorbidity, where the two comorbid conditions are phenotypically and aetiologically identical to what that anxiety would mean in persons with a neurotypical development, whether it is an anxiety that has been phenotypically modified by the pathological processes of the autism spectrum disorders, thus resulting in a specific variant of these latter, or whether we are dealing with a false comorbidity resulting from rather inaccurate differential diagnoses. DEVELOPMENT. The article puts forward two hypotheses to explain this co-occurrence, which provide each other with feedback and are little more than our reflections on the scientific evidence we have available today, but expressed aloud. The first is the 'social error' hypothesis, which considers that the maladjustments in the social behaviour of persons with autism (which arises from alterations affecting the processes involved in social cognition) help to aggravate anxiety in autism. The second hypothesis, referring to allostatic load, holds that anxiety is a response to chronic stress, wear or exhaustion that is produced by the hyperactivation of certain structures in the limbic system. CONCLUSIONS. The prototypical manifestations of anxiety present in the person with autism are not always related with the same biopsychosocial variables as those observed in persons without autism. Evidence points to hyper-reactive flee-or-fight responses (hypervigilance) when the person finds him or herself outside their comfort zone, and supports the hypotheses of 'social error' and of decompensation of the allostatic mechanism that makes it possible to cope with stress.

Quantitative analysis of dental microwear in hadrosaurid dinosaurs, and the implications for hypotheses of jaw mechanics and feeding

Science.gov (United States)

Williams, Vincent S.; Barrett, Paul M.; Purnell, Mark A.

2009-01-01

Understanding the feeding mechanisms and diet of nonavian dinosaurs is fundamental to understanding the paleobiology of these taxa and their role in Mesozoic terrestrial ecosystems. Various methods, including biomechanical analysis and 3D computer modeling, have been used to generate detailed functional hypotheses, but in the absence of either direct observations of dinosaur feeding behavior, or close living functional analogues, testing these hypotheses is problematic. Microscopic scratches that form on teeth in vivo during feeding are known to record the relative motion of the tooth rows to each other during feeding and to capture evidence of tooth–food interactions. Analysis of this dental microwear provides a powerful tool for testing hypotheses of jaw mechanics, diet, and trophic niche; yet, quantitative analysis of microwear in dinosaurs has not been attempted. Here, we show that analysis of tooth microwear orientation provides direct evidence for the relative motions of jaws during feeding in hadrosaurid ornithopods, the dominant terrestrial herbivores of the Late Cretaceous. Statistical testing demonstrates that Edmontosaurus teeth preserve 4 distinct sets of scratches in different orientations. In terms of jaw mechanics, these data indicate an isognathic, near-vertical posterodorsal power stroke during feeding; near-vertical jaw opening; and propalinal movements in near anterior and near posterior directions. Our analysis supports the presence of a pleurokinetic hinge, and the straightness and parallelism of scratches indicate a tightly controlled occlusion. The dominance of scratched microwear fabrics suggests that Edmontosaurus was a grazer rather than a browser. PMID:19564603

A set of genes previously implicated in the hypoxia response might be an important modulator in the rat ear tissue response to mechanical stretch

Directory of Open Access Journals (Sweden)

Orgill Dennis

2007-11-01

Full Text Available Abstract Background Wounds are increasingly important in our aging societies. Pathologies such as diabetes predispose patients to chronic wounds that can cause pain, infection, and amputation. The vacuum assisted closure device shows remarkable outcomes in wound healing. Its mechanism of action is unclear despite several hypotheses advanced. We previously hypothesized that micromechanical forces can heal wounds. To understand better the biological response of soft tissue to forces, rat ears in vivo were stretched and their gene expression patterns over time obtained. The absolute enrichment (AE algorithm that obtains a combined up and down regulated picture of the expression analysis was implemented. Results With the use of AE, the hypoxia gene set was the most important at a highly significant level. A co-expression network analysis showed that important co-regulated members of the hypoxia pathway include a glucose transporter (slc2a8, heme oxygenase, and nitric oxide synthase2 among others. Conclusion It appears that the hypoxia pathway may be an important modulator of response of soft tissue to forces. This finding gives us insights not only into the underlying biology, but also into clinical interventions that could be designed to mimic within wounded tissue the effects of forces without all the negative effects that forces themselves create.

49 CFR 173.23 - Previously authorized packaging.

Science.gov (United States)

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Previously authorized packaging. 173.23 Section... REQUIREMENTS FOR SHIPMENTS AND PACKAGINGS Preparation of Hazardous Materials for Transportation § 173.23 Previously authorized packaging. (a) When the regulations specify a packaging with a specification marking...

22 CFR 40.91 - Certain aliens previously removed.

Science.gov (United States)

2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Certain aliens previously removed. 40.91... IMMIGRANTS UNDER THE IMMIGRATION AND NATIONALITY ACT, AS AMENDED Aliens Previously Removed § 40.91 Certain aliens previously removed. (a) 5-year bar. An alien who has been found inadmissible, whether as a result...

The Hydrological Open Air Laboratory (HOAL) in Petzenkirchen: a hypotheses driven observatory

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Blöschl, G.; Blaschke, A. P.; Broer, M.; Bucher, C.; Carr, G.; Chen, X.; Eder, A.; Exner-Kittridge, M.; Farnleitner, A.; Flores-Orozco, A.; Haas, P.; Hogan, P.; Kazemi Amiri, A.; Oismüller, M.; Parajka, J.; Silasari, R.; Stadler, P.; Strauß, P.; Vreugdenhil, M.; Wagner, W.; Zessner, M.

2015-07-01

Hydrological observatories bear a lot of resemblance to the more traditional research catchment concept but tend to differ in providing more long term facilities that transcend the lifetime of individual projects, are more strongly geared towards performing interdisciplinary research, and are often designed as networks to assist in performing collaborative science. This paper illustrates how the experimental and monitoring setup of an observatory, the 66 ha Hydrological Open Air Laboratory (HOAL) in Petzenkirchen, Lower Austria, has been established in a way that allows meaningful hypothesis testing. The overarching science questions guided site selection, identifying dissertation topics and the base monitoring. The specific hypotheses guided the dedicated monitoring and sampling, individual experiments, and repeated experiments with controlled boundary conditions. The purpose of the HOAL is to advance the understanding of water related flow and transport processes involving sediments, nutrients and microbes in small catchments. The HOAL catchment is ideally suited for this purpose, because it features a range of different runoff generation processes (surface runoff, springs, tile drains, wetlands), the nutrient inputs are known, and it is convenient from a logistic point of view as all instruments can be connected to the power grid and a high speed glassfibre Local Area Network. The multitude of runoff generation mechanisms in the catchment provide a genuine laboratory where hypotheses of flow and transport can be tested, either by controlled experiments or by contrasting sub-regions of different characteristics. This diversity also ensures that the HOAL is representative of a range of catchments around the world and the specific process findings from the HOAL are applicable to a variety of agricultural catchment settings. The HOAL is operated jointly by the Vienna University of Technology and the Federal Agency for Water Management and takes advantage of the

Insights into the biogeographical history of the Lower Guinea Forest Domain: evidence for the role of refugia in the intraspecific differentiation of Aucoumea klaineana.

Science.gov (United States)

Born, Céline; Alvarez, Nadir; McKey, Doyle; Ossari, Simon; Wickings, Elisabeth Jean; Hossaert-McKey, Martine; Chevallier, Marie-Hélène

2011-01-01

Determining the biogeographical histories of rainforests is central to our understanding of the present distribution of tropical biodiversity. Ice age fragmentation of central African rainforests strongly influenced species distributions. Elevated areas characterized by higher species richness and endemism have been postulated to be Pleistocene forest refugia. However, it is often difficult to separate the effects of history and of present-day ecological conditions on diversity patterns at the interspecific level. Intraspecific genetic variation could yield new insights into history, because refugia hypotheses predict patterns not expected on the basis of contemporary environmental dynamics. Here, we test geographically explicit hypotheses of vicariance associated with the presence of putative refugia and provide clues about their location. We intensively sampled populations of Aucoumea klaineana, a forest tree sensitive to forest fragmentation, throughout its geographical range. Characterizing variation at 10 nuclear microsatellite loci, we were able to obtain phylogeographic data of unprecedented detail for this region. Using Bayesian clustering approaches, we demonstrated the presence of four differentiated genetic units. Their distribution matched that of forest refugia postulated from patterns of species richness and endemism. Our data also show differences in diversity dynamics at leading and trailing edges of the species' shifting distribution. Our results confirm predictions based on refugia hypotheses and cannot be explained on the basis of present-day ecological conditions. © 2010 Blackwell Publishing Ltd.

Revisiting the environmental Kuznets curve and pollution haven hypotheses: MIKTA sample.

Science.gov (United States)

Bakirtas, Ibrahim; Cetin, Mumin Atalay

2017-08-01

This study aims to examine the validity of the environmental Kuznets curve (EKC) and pollution haven hypotheses in Mexico, Indonesia, South Korea, Turkey, and Australia (MIKTA) countries from 1982 to 2011 by using a panel vector auto regressive (PVAR) model. Empirical findings imply that the EKC hypothesis is rejected by the MIKTA sample. However, PVAR estimations reveal Granger causality from income level, foreign direct investment (FDI) inward, and energy consumption to CO 2 emissions. Orthogonalized impulse-response functions are derived from PVAR estimations. According to the analysis results, the response of CO 2 emissions to a shock on FDI is positive. These results assert that FDI has a detrimental effect on environmental quality in MIKTA countries which means the pollution haven hypothesis is confirmed by the MIKTA sample. Therefore, MIKTA countries should revise their current economic growth plans to provide sustainable development and also re-organize their legal infrastructure to induce usage of renewable energy sources.

Complex postglacial recolonization inferred from population genetic structure of mottled sculpin Cottus bairdii in tributaries of eastern Lake Michigan, U.S.A.

Science.gov (United States)

Homola, J J; Ruetz, C R; Kohler, S L; Thum, R A

2016-11-01

This study used analyses of the genetic structure of a non-game fish species, the mottled sculpin Cottus bairdii to hypothesize probable recolonization routes used by cottids and possibly other Laurentian Great Lakes fishes following glacial recession. Based on samples from 16 small streams in five major Lake Michigan, U.S.A., tributary basins, significant interpopulation differentiation was documented (overall F ST = 0·235). Differentiation was complex, however, with unexpectedly high genetic similarity among basins as well as occasionally strong differentiation within basins, despite relatively close geographic proximity of populations. Genetic dissimilarities were identified between eastern and western populations within river basins, with similarities existing between eastern and western populations across basins. Given such patterns, recolonization is hypothesized to have occurred on three occasions from more than one glacial refugium, with a secondary vicariant event resulting from reduction in the water level of ancestral Lake Michigan. By studying the phylogeography of a small, non-game fish species, this study provides insight into recolonization dynamics of the region that could be difficult to infer from game species that are often broadly dispersed by humans. © 2016 The Fisheries Society of the British Isles.

Visual functions in phenylketonuria-evaluating the dopamine and long-chain polyunsaturated fatty acids depletion hypotheses.

Science.gov (United States)

Gramer, Gwendolyn; Förl, Birgit; Springer, Christina; Weimer, Petra; Haege, Gisela; Mackensen, Friederike; Müller, Edith; Völcker, Hans Eberhard; Hoffmann, Georg Friedrich; Lindner, Martin; Krastel, Hermann; Burgard, Peter

2013-01-01

In phenylketonuria presymptomatic treatment following newborn screening prevents severe mental and physical impairment. The reasons for subtle impairments of cerebral functions despite early treatment remain unclear. We assessed a broad spectrum of visual functions in early-treated patients with phenylketonuria and evaluated two hypotheses-the dopamine and the long-chain polyunsaturated fatty acids (LCPUFAs) depletion hypotheses. Contrast sensitivity, colour vision, electroretinography, frequency doubling technology campimetry (FDT), and their relation with blood phenylalanine and docosahexaenoic acid levels were assessed in 36 patients with phenylketonuria and 18 age-matched healthy controls. Contrast sensitivity was significantly lower and total error scores in colour vision significantly higher in patients than controls. Electroretinography results differed significantly between patients and controls. We found a trend for the effect of phenylalanine-levels on contrast sensitivity and a significant effect on colour vision/FDT results. Docosahexaenoic acid levels in erythrocytes were not associated with visual functions. This is the first evaluation of visual functions in phenylketonuria using a comprehensive ophthalmological test battery. We found no evidence supporting the long-chain polyunsaturated fatty acids depletion hypothesis. However, the effect of phenylalanine-levels on visual functions suggests that imbalance between phenylalanine and tyrosine may affect retinal dopamine levels in phenylketonuria. This is supported by the similar patterns of visual functions in patients with phenylketonuria observed in our study and patients with Parkinson's disease. Copyright © 2012 Elsevier Inc. All rights reserved.

Confidence Intervals: From tests of statistical significance to confidence intervals, range hypotheses and substantial effects

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Dominic Beaulieu-Prévost

2006-03-01

Full Text Available For the last 50 years of research in quantitative social sciences, the empirical evaluation of scientific hypotheses has been based on the rejection or not of the null hypothesis. However, more than 300 articles demonstrated that this method was problematic. In summary, null hypothesis testing (NHT is unfalsifiable, its results depend directly on sample size and the null hypothesis is both improbable and not plausible. Consequently, alternatives to NHT such as confidence intervals (CI and measures of effect size are starting to be used in scientific publications. The purpose of this article is, first, to provide the conceptual tools necessary to implement an approach based on confidence intervals, and second, to briefly demonstrate why such an approach is an interesting alternative to an approach based on NHT. As demonstrated in the article, the proposed CI approach avoids most problems related to a NHT approach and can often improve the scientific and contextual relevance of the statistical interpretations by testing range hypotheses instead of a point hypothesis and by defining the minimal value of a substantial effect. The main advantage of such a CI approach is that it replaces the notion of statistical power by an easily interpretable three-value logic (probable presence of a substantial effect, probable absence of a substantial effect and probabilistic undetermination. The demonstration includes a complete example.

Testing the emergence of New Caledonia: fig wasp mutualism as a case study and a review of evidence.

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Astrid Cruaud

Full Text Available While geologists suggest that New Caledonian main island (Grande Terre was submerged until ca 37 Ma, biologists are struck by the presence of supposedly Gondwanan groups on the island. Among these groups are the Oreosycea fig trees (Ficus, Moraceae and their Dolichoris pollinators (Hymenoptera, Agaonidae. These partners are distributed in the Paleotropics and Australasia, suggesting that their presence on New Caledonia could result from Gondwanan vicariance. To test this hypothesis, we obtained mitochondrial and nuclear markers (5.3 kb from 28 species of Dolichoris, used all available sequences for Oreosycea, and conducted phylogenetic and dating analyses with several calibration strategies. All our analyses ruled out a vicariance scenario suggesting instead that New Caledonian colonization by Dolichoris and Oreosycea involved dispersal across islands from Sundaland ca 45.9-32.0 Ma. Our results show that successful long-distance dispersal of obligate mutualists may happen further suggesting that presence of intimate mutualisms on isolated islands should not be used as a priori evidence for vicariance. Comparing our results to a review of all the published age estimates for New Caledonian plant and animal taxa, we showed that support for a vicariant origin of the island biota is still lacking. Finally, as demonstrating a causal relationship between geology and biology requires independent evidence, we argue that a priori assumptions about vicariance or dispersal should not be used to constrain chronograms. This circular reasoning could lead to under or overestimation of age estimates.

A time-calibrated phylogeny of southern hemisphere stoneflies: Testing for Gondwanan origins.

Science.gov (United States)

McCulloch, Graham A; Wallis, Graham P; Waters, Jonathan M

2016-03-01

For more than two centuries biogeographers have attempted to explain why terrestrial or freshwater lineages have geographic distributions broken by oceans, with these disjunct distributions either attributed to vicariance associated with Gondwanan fragmentation or trans-oceanic dispersal. Stoneflies (order: Plecoptera) are a widespread order of freshwater insects whose poor dispersal ability and intolerance for salt water make them ideal candidates for Gondwanan relicts - taxa whose distribution can be explained by vicariant isolation driven by the breakup of Gondwana. Here we reconstruct the phylogenetic relationships among southern hemisphere stoneflies (5 families; 86 genera) using 2864bp of mitochondrial (COI) and nuclear (18S, H3) DNA, with a calibrated relaxed molecular clock used to estimate the chronology of diversification. Our analysis suggests that largely antitropical stonefly sub-orders, Arctoperlaria (northern hemisphere) and Antarctoperlaria (southern hemisphere), were formed approximately 121Ma (95% prior probability distribution 107-143Ma), which may reflect the vicariant rifting of the supercontinent Pangaea. Subsequently, we infer that a single Arctoperlaria lineage has dispersed into southern hemisphere 76Ma (95% range 65-98Ma). The majority of divergences between South American and Australian stonefly lineages appear to coincide with the opening of Drake Passage around 40Ma, suggesting vicariant isolation of these landmasses may be responsible for these biogeographic disjunctions. In contrast, divergences between New Zealand lineages and their sister taxa appear to post-date vicariant timeframes, implying more recent dispersal events. Copyright © 2015 Elsevier Inc. All rights reserved.

Properties of hypothesis testing techniques and (Bayesian) model selection for exploration-based and theory-based (order-restricted) hypotheses

NARCIS (Netherlands)

Kuiper, Rebecca M.; Nederhoff, Tim; Klugkist, Irene

2015-01-01

In this paper, the performance of six types of techniques for comparisons of means is examined. These six emerge from the distinction between the method employed (hypothesis testing, model selection using information criteria, or Bayesian model selection) and the set of hypotheses that is

Nearly Complete 28S rRNA Gene Sequences Confirm New Hypotheses of Sponge Evolution

Science.gov (United States)

Thacker, Robert W.; Hill, April L.; Hill, Malcolm S.; Redmond, Niamh E.; Collins, Allen G.; Morrow, Christine C.; Spicer, Lori; Carmack, Cheryl A.; Zappe, Megan E.; Pohlmann, Deborah; Hall, Chelsea; Diaz, Maria C.; Bangalore, Purushotham V.

2013-01-01

The highly collaborative research sponsored by the NSF-funded Assembling the Porifera Tree of Life (PorToL) project is providing insights into some of the most difficult questions in metazoan systematics. Our understanding of phylogenetic relationships within the phylum Porifera has changed considerably with increased taxon sampling and data from additional molecular markers. PorToL researchers have falsified earlier phylogenetic hypotheses, discovered novel phylogenetic alliances, found phylogenetic homes for enigmatic taxa, and provided a more precise understanding of the evolution of skeletal features, secondary metabolites, body organization, and symbioses. Some of these exciting new discoveries are shared in the papers that form this issue of Integrative and Comparative Biology. Our analyses of over 300 nearly complete 28S ribosomal subunit gene sequences provide specific case studies that illustrate how our dataset confirms new hypotheses of sponge evolution. We recovered monophyletic clades for all 4 classes of sponges, as well as the 4 major clades of Demospongiae (Keratosa, Myxospongiae, Haploscleromorpha, and Heteroscleromorpha), but our phylogeny differs in several aspects from traditional classifications. In most major clades of sponges, families within orders appear to be paraphyletic. Although additional sampling of genes and taxa are needed to establish whether this pattern results from a lack of phylogenetic resolution or from a paraphyletic classification system, many of our results are congruent with those obtained from 18S ribosomal subunit gene sequences and complete mitochondrial genomes. These data provide further support for a revision of the traditional classification of sponges. PMID:23748742

Dependence on Solar Phase Angle and Grain Size of the Spectral Reflectance of the Railroad Valley Playa for GOSAT/GOSAT-2 Vicarious Calibration

Science.gov (United States)

Arai, T.; Matsunaga, T.

2017-12-01

GOSAT and the next generation GOSAT-2 satellites estimate the concentration of greenhouse gasses, and distribution of aerosol and cloud to observe solar light reflection and radiation from surface and atmosphere of the Earth. Precise information of the surface and the bidirectional reflectance distribution function (BRDF) are required for the estimation because the surface reflectance of solar light varies with the observation geometry and the surface condition. The purpose of this study is to search an appropriate BRDF model of the GOSAT calibration site (Railroad Valley playa). In 2017, JAXA, NIES, and NASA/OCO-2 teams collaboratively performed 9th vicarious experiments by the simultaneous observation with GOSAT, OCO-2, and ground-based equipment (Kuze et al., 2014) at the Railroad Valley from June 25 to 30. We performed the BRDF measurement to observe solar light reflection by varying with observed angles using a spectroradiometer (FieldSpec4, ASD Inc.) mounted on a one-axis goniometer. The surface sand was shifted to several sizes of grain (75, 125, 250, 500, and 1000 μm), which was measured for the limited area of 5mm diameter with a collimating lens (74-UV, OceanOptics). The BRDF parameters for the observed reflectance were determined by the least squares fitting with the free parameters of a single scattering albedo and an asymmetric factor (Hapke, 2012) for the ultraviolet to near infrared wavelength bands of GOSAT. The resulting value of the single scattering albedo increased with decreasing the grain size of the sands. The observed reflectance of the fine grain sands (below 250 μm) is not varied with observed phase angles (solar incident light - surface sand - detector) as a Lambertian reflectance, but the spectra of coarse grain sands (above 500 μm) are varied with the observation angles. Therefore, a priori information of the target surface such as grain size is required for the determination of the precise reflectance of the target.

Increased carbon sequestration in a Danish beech forest during 1996-2016: Observations and hypotheses.

Science.gov (United States)

Pilegaard, Kim; Ibrom, Andreas

2017-04-01

A study of the net exchange of CO2 (NEE) between the atmosphere and a beech forest near Sorø, Denmark, during 14 years (1996-2009) showed that the beech forest acted as an increasing sink of CO2 [1]. A significant increase in gross primary production (GPP) and a smaller and not significant increase in ecosystem respiration (RE) were also found. Thus, the increased NEE was mainly attributed to an increase in GPP. The length of the carbon uptake period (CUP) significantly increased, whereas there was a no increase in the leafed period (LP). This means that the leaves stayed active longer. The increase in the carbon uptake period explained about half of the increasing NEE. The remaining increase was believed to be due to an observed increased uptake capacity of the canopy and increased annual radiation efficiency[2]. The causes for this were hypothesized to be a combination of increase in atmospheric CO2 concentration, higher summer precipitation, and increased availability of N. A higher nitrogen content in the leaves was observed towards the end of the observation period. An updated analysis of the flux data, now including the years 1996-2016, confirms the increasing trend in carbon sequestration of the forest, an increasingly longer growing season, and a significant correlation of NEE and CUP, however, similarly to the first study, the increase in CUP only explains about half of the total increase. Here we investigate three hypotheses for the remaining reasons for the increase: H1: increased canopy nitrogen content H2: carbon dioxide fertilisation H3: increased water availability due to changing precipitation patterns. We describe the multiannual development of canopy photosynthesis capacity with regression analysis and perform sensitivity studies with the canopy model MAESTRA [3] to investigate the above hypotheses. The results will be presented, critically discussed and interpreted with respect to general effects of global climate change and site specific, local

Consider the Alternative: The Effects of Causal Knowledge on Representing and Using Alternative Hypotheses in Judgments under Uncertainty

Science.gov (United States)

Hayes, Brett K.; Hawkins, Guy E.; Newell, Ben R.

2016-01-01

Four experiments examined the locus of impact of causal knowledge on consideration of alternative hypotheses in judgments under uncertainty. Two possible loci were examined; overcoming neglect of the alternative when developing a representation of a judgment problem and improving utilization of statistics associated with the alternative…

WAYS OF ACQUIRING FLYING PHOBIA.

Science.gov (United States)

Schindler, Bettina; Vriends, Noortje; Margraf, Jürgen; Stieglitz, Rolf-Dieter

2016-02-01

The few studies that have explored how flying phobia is acquired have produced contradictory results. We hypothesized that classical conditioning plays a role in acquiring flying phobia and investigated if vicarious (model) learning, informational learning through media, and experiencing stressful life events at the time of onset of phobia also play a role. Thirty patients with flying phobia and thirty healthy controls matched on age, sex, and education were interviewed with the Mini-DIPS, the short German version of the Anxiety Disorders Interview Schedule (DSM-IV diagnostic criteria) and the Fear-of-Flying History Interview. Fifty Percent of patients with flying phobia and 53% of healthy controls reported frightening events in the air. There was no significant difference between the two samples. Thus there were not more classical conditioning events for patients with flying phobia. There also was no significant difference between the two samples for vicarious (model) learning: 37% of flying phobia patients and 23% of healthy controls felt influenced by model learning. The influence of informational learning through media was significantly higher for the clinical sample (70%) than for the control group (37%). Patients with flying phobia experienced significantly more stressful life events in the period of their frightening flight experience (60%) than healthy controls (19%). Frightening experiences while flying are quite common, but not everybody develops a flying phobia. Stressful life events and other factors might enhance conditionability. Informational learning through negative media reports probably reinforces the development of flying phobia. Clinical implications are discussed. © 2015 Wiley Periodicals, Inc.

A Critical Analysis Of The Majority Judgment In F V Minister Of Safety And Security 2012 1 Sa 536 (Cc

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James Linscott

2014-12-01

Full Text Available The majority judgment of Mogoeng CJ in F v Minister of Safety and Security 2012 1 SA 536 (CC purports to be a straightforward application of the reasoning of the Constitutional Court in K v Minister of Safety and Security 2005 6 SA 419 (CC, in which the court updated and constitutionalised the "standard test" for vicarious liability in deviation cases originally set out in Minister of Police v Rabie 1986 1 SA 117 (A by holding that constitutional and other policy norms now play an important role in deciding questions of vicarious liability. However, it is respectfully submitted that a close reading of the majority judgment in F reveals that the judge misconstrues several key concepts related to the doctrine of vicarious liability. In particular, the judge seems to suggest that there are separate and different tests for vicarious liability in instances where an employee has plainly committed a delict in the course and scope of his employment, and where he has to some extent deviated from his employment duties. In fact, there is a single overarching test for vicarious liability - the course and scope rule - but various subsidiary tests are used by the courts to address difficult or borderline cases. It is also questionable whether F truly is a "typical deviation case", as the judge asserts. The judge then applies the constitutionalised test for vicarious liability originally set out in K in a manner which is subtly, but significantly, different from how it was deployed in that case. In particular, Mogoeng CJ's implication that it is not necessary for a court to consider the second leg of the Rabie test in circumstances where the employee wrongdoer has clearly subjectively intended to further the interests of his employer is undesirable and should not be supported. Furthermore, the judge identifies the question of whether or not there is an "intimate link" between the conduct of the employee wrongdoer and the business of his employer as one of the

A priori assumptions about characters as a cause of incongruence between molecular and morphological hypotheses of primate interrelationships.

Science.gov (United States)

Tornow, Matthew A; Skelton, Randall R

2012-01-01

When molecules and morphology produce incongruent hypotheses of primate interrelationships, the data are typically viewed as incompatible, and molecular hypotheses are often considered to be better indicators of phylogenetic history. However, it has been demonstrated that the choice of which taxa to include in cladistic analysis as well as assumptions about character weighting, character state transformation order, and outgroup choice all influence hypotheses of relationships and may positively influence tree topology, so that relationships between extant taxa are consistent with those found using molecular data. Thus, the source of incongruence between morphological and molecular trees may lie not in the morphological data themselves but in assumptions surrounding the ways characters evolve and their impact on cladistic analysis. In this study, we investigate the role that assumptions about character polarity and transformation order play in creating incongruence between primate phylogenies based on morphological data and those supported by multiple lines of molecular data. By releasing constraints imposed on published morphological analyses of primates from disparate clades and subjecting those data to parsimony analysis, we test the hypothesis that incongruence between morphology and molecules results from inherent flaws in morphological data. To quantify the difference between incongruent trees, we introduce a new method called branch slide distance (BSD). BSD mitigates many of the limitations attributed to other tree comparison methods, thus allowing for a more accurate measure of topological similarity. We find that releasing a priori constraints on character behavior often produces trees that are consistent with molecular trees. Case studies are presented that illustrate how congruence between molecules and unconstrained morphological data may provide insight into issues of polarity, transformation order, homology, and homoplasy.

Impact of previously disadvantaged land-users on sustainable ...

African Journals Online (AJOL)

Impact of previously disadvantaged land-users on sustainable agricultural ... about previously disadvantaged land users involved in communal farming systems ... of input, capital, marketing, information and land use planning, with effect on ...

A New Species of Pengornithidae (Aves: Enantiornithes) from the Lower Cretaceous of China Suggests a Specialized Scansorial Habitat Previously Unknown in Early Birds

Science.gov (United States)

Hu, Han; O’Connor, Jingmai K.; Zhou, Zhonghe

2015-01-01

We describe a new enantiornithine bird, Parapengornis eurycaudatus gen. et sp. nov. from the Lower Cretaceous Jiufotang Formation of Liaoning, China. Although morphologically similar to previously described pengornithids Pengornis houi, Pengornis IVPP V18632, and Eopengornis martini, morphological differences indicate it represents a new taxon of the Pengornithidae. Based on new information from this specimen we reassign IVPP V18632 to Parapengornis sp. The well preserved pygostyle of the new specimen elucidates the morphology of this element for the clade, which is unique in pengornithids among Mesozoic birds. Similarities with modern scansores such as woodpeckers may indicate a specialized vertical climbing and clinging behavior that has not previously been inferred for early birds. The new specimen preserves a pair of fully pennaceous rachis-dominated feathers like those in the holotype of Eopengornis martini; together with the unique morphology of the pygostyle, this discovery lends evidence to early hypotheses that rachis-dominated feathers may have had a functional significance. This discovery adds to the diversity of ecological niches occupied by enantiornithines and if correct reveals are remarkable amount of locomotive differentiation among Enantiornithes. PMID:26039693

A new species of pengornithidae (aves: enantiornithes from the lower cretaceous of China suggests a specialized scansorial habitat previously unknown in early birds.

Directory of Open Access Journals (Sweden)

Han Hu

Full Text Available We describe a new enantiornithine bird, Parapengornis eurycaudatus gen. et sp. nov. from the Lower Cretaceous Jiufotang Formation of Liaoning, China. Although morphologically similar to previously described pengornithids Pengornis houi, Pengornis IVPP V18632, and Eopengornis martini, morphological differences indicate it represents a new taxon of the Pengornithidae. Based on new information from this specimen we reassign IVPP V18632 to Parapengornis sp. The well preserved pygostyle of the new specimen elucidates the morphology of this element for the clade, which is unique in pengornithids among Mesozoic birds. Similarities with modern scansores such as woodpeckers may indicate a specialized vertical climbing and clinging behavior that has not previously been inferred for early birds. The new specimen preserves a pair of fully pennaceous rachis-dominated feathers like those in the holotype of Eopengornis martini; together with the unique morphology of the pygostyle, this discovery lends evidence to early hypotheses that rachis-dominated feathers may have had a functional significance. This discovery adds to the diversity of ecological niches occupied by enantiornithines and if correct reveals are remarkable amount of locomotive differentiation among Enantiornithes.

Factors that encourage females to pursue physical science careers: Testing five common hypotheses

Science.gov (United States)

Hazari, Zahra; Potvin, Geoff; Lock, Robynne M.; Lung, Florin; Sadler, Philip M.; Sonnert, Gerhard

2012-03-01

There are many hypotheses regarding factors that may encourage female students to pursue careers in the physical sciences. Using Propensity Score Matching (PSM) on national data (n=7505) drawn from the Persistence Research in Science and Engineering (PRiSE) project, we test five commonly held beliefs including having a single-sex physics class, having a female physics teacher, having female scientist guest speakers in physics class, discussing the work of women scientists in physics class, and discussing the under-representation of women in physics class. The effect of these experiences is compared for female students who are matched on several factors, including parental education, prior science/math interests, and academic background, thereby controlling for the effect of many confounding variables.

Determining root correspondence between previously and newly detected objects

Science.gov (United States)

Paglieroni, David W.; Beer, N Reginald

2014-06-17

A system that applies attribute and topology based change detection to networks of objects that were detected on previous scans of a structure, roadway, or area of interest. The attributes capture properties or characteristics of the previously detected objects, such as location, time of detection, size, elongation, orientation, etc. The topology of the network of previously detected objects is maintained in a constellation database that stores attributes of previously detected objects and implicitly captures the geometrical structure of the network. A change detection system detects change by comparing the attributes and topology of new objects detected on the latest scan to the constellation database of previously detected objects.

An extension of hypotheses regarding rapid-acting, treatment-refractory, and conventional antidepressant activity of dextromethorphan and dextrorphan.

Science.gov (United States)

Lauterbach, Edward C

2012-06-01

It was previously hypothesized that dextromethorphan (DM) and dextrorphan (DX) may possess antidepressant properties, including rapid and conventional onsets of action and utility in treatment-refractory depression, based on pharmacodynamic similarities to ketamine. These similarities included sigma-1 (σ(1)) agonist and NMDA antagonist properties, calcium channel blockade, muscarinic binding, serotonin transporter (5HTT) inhibition, and μ receptor potentiation. Here, six specific hypotheses are developed in light of additional mechanisms and evidence. Comparable potencies to ketamine for DM and DX are detailed for σ(1) (DX>DM>ketamine), NMDA PCP site (DX>ketamine>DM), and muscarinic (DX>ketamine>DM) receptors, 5HTT (DM>DX≫ketamine), and NMDA antagonist potentiation of μ receptor stimulation (DM>ketamine). Rapid acting antidepressant properties of DM include NMDA high-affinity site, NMDR-2A, and functional NMDR-2B receptor antagonism, σ(1) stimulation, putative mTOR activation (by σ(1) stimulation, μ potentiation, and 5HTT inhibition), putative AMPA receptor trafficking (by mTOR activation, PCP antagonism, σ(1) stimulation, μ potentiation, and 5HTT inhibition), and dendritogenesis, spinogenesis, synaptogenesis, and neuronal survival by NMDA antagonism and σ(1) and mTOR signaling. Those for dextrorphan include NMDA high-affinity site and NMDR-2A antagonism, σ(1) stimulation, putative mTOR activation (by σ(1) stimulation and ß adrenoreceptor stimulation), putative AMPA receptor trafficking (by mTOR activation, PCP antagonism, σ(1) stimulation, ß stimulation, and μ antagonism), and dendritogenesis, spinogenesis, synaptogenesis, and neuronal survival by NMDA antagonism and σ(1) and mTOR signaling. Conventional antidepressant properties for dextromethorphan and dextrorphan include 5HTT and norepinephrine transporter inhibition, σ(1) stimulation, NMDA and PCP antagonism, and possible serotonin 5HT1b/d receptor stimulation. Additional properties for

Can MOND type hypotheses be tested in a free fall laboratory environment?

Science.gov (United States)

Das, Saurya; Patitsas, S. N.

2013-05-01

The extremely small accelerations of objects required for the onset of modified Newtonian dynamics, or modified Newtonian dynamics (MOND), makes testing the hypothesis in conventional terrestrial laboratories virtually impossible. This is due to the large background acceleration of Earth, which is transmitted to the acceleration of test objects within an apparatus. We show, however, that it may be possible to test MOND-type hypotheses with experiments using a conventional apparatus capable of tracking very small accelerations of its components but performed in locally inertial frames such as artificial satellites and other freely falling laboratories. For example, experiments involving an optical interferometer or a torsion balance in these laboratories would show nonlinear dynamics and displacement amplitudes larger than expected. These experiments may also be able to test potential violations of the strong equivalence principle by MOND and to distinguish between its two possible interpretations (modified inertia and modified gravity).

A multilocus evaluation of ermine (Mustela erminea) across the Holarctic, testing hypotheses of Pleistocene diversification in response to climate change

Science.gov (United States)

Dawson, Natalie G.; Hope, Andrew G.; Talbot, Sandra L.; Cook, Joseph A.

2013-01-01

Aim: We examined data for ermine (Mustela erminea) to test two sets of diversification hypotheses concerning the number and location of late Pleistocene refugia, the timing and mode of diversification, and the evolutionary influence of insularization. Location: Temperate and sub-Arctic Northern Hemisphere. Methods: We used up to two mitochondrial and four nuclear loci from 237 specimens for statistical phylogeographical and demographic analyses. Coalescent species-tree estimation used a Bayesian approach for clade divergence based on external mutation rate calibrations. Approximate Bayesian methods were used to assess population size, timing of divergence and gene flow. Results: Limited structure coupled with evidence of population growth across broad regions, including previously ice-covered areas, indicated expansion from multiple centres of differentiation, but high endemism along the North Pacific coast (NPC). A bifurcating model of diversification with recent growth spanning three glacial cycles best explained the empirical data. Main conclusions: A newly identified clade in North America indicated a fourth refugial area for ermine. The shallow coalescence of all extant ermine reflects a recent history of diversification overlying a deeper fossil record. Post-glacial colonization has led to potential contact zones for multiple lineages in north-western North America. A model of diversification of ermine accompanied by recent gene flow was marginally less well supported than a model of divergence of major clades in response to the most recent glacial cycles.

Erlotinib-induced rash spares previously irradiated skin

International Nuclear Information System (INIS)

Lips, Irene M.; Vonk, Ernest J.A.; Koster, Mariska E.Y.; Houwing, Ronald H.

2011-01-01

Erlotinib is an epidermal growth factor receptor inhibitor prescribed to patients with locally advanced or metastasized non-small cell lung carcinoma after failure of at least one earlier chemotherapy treatment. Approximately 75% of the patients treated with erlotinib develop acneiform skin rashes. A patient treated with erlotinib 3 months after finishing concomitant treatment with chemotherapy and radiotherapy for non-small cell lung cancer is presented. Unexpectedly, the part of the skin that had been included in his previously radiotherapy field was completely spared from the erlotinib-induced acneiform skin rash. The exact mechanism of erlotinib-induced rash sparing in previously irradiated skin is unclear. The underlying mechanism of this phenomenon needs to be explored further, because the number of patients being treated with a combination of both therapeutic modalities is increasing. The therapeutic effect of erlotinib in the area of the previously irradiated lesion should be assessed. (orig.)

Testing Biological Hypotheses with Embodied Robots: Adaptations, Accidents, and By-Products in the Evolution of Vertebrates

OpenAIRE

Roberts, Sonia F.; Hirokawa, Jonathan; Rosenblum, Hannah G.; Sakhtah, Hassan; Gutierrez, Andres A.; Porter, Marianne E.; Long, John H.

2014-01-01

Evolutionary robotics allows biologists to test hypotheses about extinct animals. In our case, we modeled some of the first vertebrates, jawless fishes, in order to study the evolution of the trait after which vertebrates are named: vertebrae. We tested the hypothesis that vertebrae are an adaptation for enhanced feeding and fleeing performance. We created a population of autonomous embodied robots, Preyro, in which the number of vertebrae, N, were free to evolve. In addition, two other trait...

Life History theory hypotheses on child growth: Potential implications for short and long-term child growth, development and health.

Science.gov (United States)

Said-Mohamed, Rihlat; Pettifor, John M; Norris, Shane A

2018-01-01

Life history theory integrates ecological, physiological, and molecular layers within an evolutionary framework to understand organisms' strategies to optimize survival and reproduction. Two life history hypotheses and their implications for child growth, development, and health (illustrated in the South African context) are reviewed here. One hypothesis suggests that there is an energy trade-off between linear growth and brain growth. Undernutrition in infancy and childhood may trigger adaptive physiological mechanisms prioritizing the brain at the expense of body growth. Another hypothesis is that the period from conception to infancy is a critical window of developmental plasticity of linear growth, the duration of which may vary between and within populations. The transition from infancy to childhood may mark the end of a critical window of opportunity for improving child growth. Both hypotheses emphasize the developmental plasticity of linear growth and the potential determinants of growth variability (including the role of parent-offspring conflict in maternal resources allocation). Implications of these hypotheses in populations with high burdens of undernutrition and infections are discussed. In South Africa, HIV/AIDS during pregnancy (associated with adverse birth outcomes, short duration of breastfeeding, and social consequences) may lead to a shortened window of developmental plasticity of growth. Furthermore, undernutrition and infectious diseases in children living in South Africa, a country undergoing a rapid nutrition transition, may have adverse consequences on individuals' cognitive abilities and risks of cardio-metabolic diseases. Studies are needed to identify physiological mechanisms underlying energy allocation between biological functions and their potential impacts on health. © 2017 Wiley Periodicals, Inc.

Exhaustive sampling of docking poses reveals binding hypotheses for propafenone type inhibitors of P-glycoprotein.

Directory of Open Access Journals (Sweden)

Freya Klepsch

2011-05-01

Full Text Available Overexpression of the xenotoxin transporter P-glycoprotein (P-gp represents one major reason for the development of multidrug resistance (MDR, leading to the failure of antibiotic and cancer therapies. Inhibitors of P-gp have thus been advocated as promising candidates for overcoming the problem of MDR. However, due to lack of a high-resolution structure the concrete mode of interaction of both substrates and inhibitors is still not known. Therefore, structure-based design studies have to rely on protein homology models. In order to identify binding hypotheses for propafenone-type P-gp inhibitors, five different propafenone derivatives with known structure-activity relationship (SAR pattern were docked into homology models of the apo and the nucleotide-bound conformation of the transporter. To circumvent the uncertainty of scoring functions, we exhaustively sampled the pose space and analyzed the poses by combining information retrieved from SAR studies with common scaffold clustering. The results suggest propafenone binding at the transmembrane helices 5, 6, 7 and 8 in both models, with the amino acid residue Y307 playing a crucial role. The identified binding site in the non-energized state is overlapping with, but not identical to, known binding areas of cyclic P-gp inhibitors and verapamil. These findings support the idea of several small binding sites forming one large binding cavity. Furthermore, the binding hypotheses for both catalytic states were analyzed and showed only small differences in their protein-ligand interaction fingerprints, which indicates only small movements of the ligand during the catalytic cycle.

Replicated population divergence caused by localized coevolution? A test of three hypotheses in the red crossbill-lodgepole pine system.

Science.gov (United States)

Edelaar, P; Benkman, C W

2006-09-01

Several lines of evidence support the hypothesis that local populations of red crossbills (Loxia curvirostra complex) enter into a predator-prey arms race with lodgepole pine (Pinus contorta latifolia) in the absence of competing pine squirrels (Tamiasciurus hudsonicus). Nevertheless, the alternative hypotheses that neutral evolution or factors other than squirrels have caused crossbill population differentiation have not been thoroughly tested. We compared crossbill and pine cone morphology between island populations where squirrels are absent or present, and mainland sites where squirrels are present, in order to distinguish among these hypotheses. All comparisons supported an effect of squirrel absence, not island status, on crossbill and cone morphology. Hence our results provide further evidence that strong localized coevolutionary interactions in a geographic mosaic have driven adaptive population differentiation. In addition, vocal differentiation of crossbills was related to the absence of squirrels, but not to island status. As morphological and vocal differentiation is correlated with reproductive isolation in crossbills, the geographic mosaic of coevolution also seems to promote ecological speciation.

Automatic electromagnetic valve for previous vacuum

International Nuclear Information System (INIS)

Granados, C. E.; Martin, F.

1959-01-01

A valve which permits the maintenance of an installation vacuum when electric current fails is described. It also lets the air in the previous vacuum bomb to prevent the oil ascending in the vacuum tubes. (Author)

Obesity and Cancer: Existing and New Hypotheses for a Causal Connection

Directory of Open Access Journals (Sweden)

Trevor W. Stone

2018-04-01

Full Text Available Existing explanations of obesity-associated cancer emphasise direct mutagenic effects of dietary components or hormonal imbalance. Some of these hypotheses are reviewed briefly, but recent evidence suggests a major role for chronic inflammation in cancer risk, possibly involving dietary content. These ideas include the inflammation-induced activation of the kynurenine pathway and its role in feeding and metabolism by activation of the aryl hydrocarbon receptor (AHR and by modulating synaptic transmission in the brain. Evidence for a role of the kynurenine pathway in carcinogenesis then provides a potentially major link between obesity and cancer. A second new hypothesis is based on evidence that serine proteases can deplete cells of the tumour suppressors Deleted in Colorectal Cancer (DCC and neogenin. These enzymes include mammalian chymotryptic proteases released by pro-inflammatory neutrophils and macrophages. Blood levels of chymotrypsin itself increase in parallel with food intake. The mechanistically similar bacterial enzyme subtilisin is widespread in the environment, animal probiotics, meat processing and cleaning products. Simple public health schemes in these areas, with selective serine protease inhibitors and AHR antagonists and could prevent a range of intestinal and other cancers. Keywords: Obesity, Serine proteases, Chymotrypsin, Subtilisin, Dependence receptors, DCC, Kynurenine

Substance use and misuse in burn patients: Testing the classical hypotheses of the interaction between post-traumatic symptomatology and substance use.

Science.gov (United States)

Eiroa-Orosa, Francisco Jose; Giannoni-Pastor, Anna; Fidel-Kinori, Sara Guila; Argüello, José María

2016-01-01

The authors aimed to test whether the three classical hypotheses of the interaction between post-traumatic symptomatology and substance use (high risk of trauma exposure, susceptibility for post-traumatic symptomatology, and self-medication of symptoms), may be useful in the understanding of substance use among burn patients. Substance use data (nicotine, alcohol, cannabis, amphetamines, cocaine, opiates, and tranquilizers) and psychopathology measures among burn patients admitted to a burn unit and enrolled in a longitudinal observational study were analyzed. Lifetime substance use information (n = 246) was incorporated to analyses aiming to test the high risk hypothesis. Only patients assessed for psychopathology in a 6-month follow-up (n = 183) were included in prospective analyses testing the susceptibility and self-medication hypotheses. Regarding the high risk hypothesis, results show a higher proportion of heroin and tranquilizer users compared to the general population. Furthermore, in line with the susceptibility hypothesis, higher levels of symptomatology were found in lifetime alcohol, tobacco, and drug users during recovery. The self-medication hypothesis could be tested partially due to the hospital stay "cleaning" effect, but severity of symptoms was linked to the amount of caffeine, nicotine, alcohol, and cannabis use after discharge. It was found that the 3 classical hypotheses could be used to understand the link between traumatic experiences and substance use explaining different patterns of burn patient's risk for trauma exposure and emergence of symptomatology.

Human and animal invasive muscular sarcocystosis in Malaysia--recent cases, review and hypotheses.

Science.gov (United States)

Tappe, D; Abdullah, S; Heo, C C; Kannan Kutty, M; Latif, B

2013-09-01

Sarcocystosis, an unusual parasitic zoonotic disease, is caused by coccidian/ apicomplexan protozoa in humans and animals. The parasites usually develop in a heteroxenous predator-prey life-cycle involving final (carnivore) and intermediate (omnivore/herbivore) hosts. Besides the intestinal, non-invasive form of the disease in which humans and animals are the definitive hosts for certain Sarcocystis spp., the invasive form has come to recent attention. In the latter, humans and animals serve as intermediate host harbouring sarcocysts in their muscle tissue. Already in 1991 sarcocystosis was seen as a potential emerging food borne zoonosis in Malaysia, and in 2011 and 2012 the largest cluster of symptomatic human muscular sarcocystosis world-wide was reported from Tioman Island, Pahang state. In this review, we focus on invasive sarcocystosis in humans and animals in Malaysia, review the recorded cases and epidemiology, and present hypotheses.

Evaluating hypotheses of basal animal phylogeny using complete sequences of large and small subunit rRNA

International Nuclear Information System (INIS)

Medina, Monica; Collins, Allen G.; Silberman, Jeffrey; Sogin, Mitchell L.

2001-01-01

We studied the evolutionary relationships among basal metazoan lineages by using complete large subunit (LSU) and small subunit (SSU) ribosomal RNA sequences for 23 taxa. After identifying competing hypotheses, we performed maximum likelihood searches for trees conforming to each hypothesis. Kishino-Hasegawa tests were used to determine whether the data (LSU, SSU, and combined) reject any of the competing hypotheses. We also conducted unconstrained tree searches, compared the resulting topologies, and calculated bootstrap indices. Shimodaira-Hasegawa tests were applied to determine whether the data reject any of the topologies resulting from the constrained and unconstrained tree searches. LSU, SSU, and the combined data strongly contradict two assertions pertaining to sponge phylogeny. Hexactinellid sponges are not likely to be the basal lineage of amonophyletic Porifera or the sister group to all other animals. Instead, Hexactinellida and Demospongia form a well-supported clade of siliceous sponges, Silicea. It remains unclear, on the basis of these data alone, whether the calcarean sponges are more closely related to Silicea or to nonsponge animals. The SSU and combined data reject the hypothesis that Bilateria is more closely related to Ctenophora than it is to Cnidaria, whereas LSU data alone do not refute either hypothesis. LSU and SSU data agree in supporting the monophyly of Bilateria, Cnidaria, Ctenophora, and Metazoa. LSU sequence data reveal phylogenetic structure in a data set with limited taxon sampling. Continued accumulation of LSU sequences should increase our understanding of animal phylogeny

Secondary recurrent miscarriage is associated with previous male birth.

LENUS (Irish Health Repository)

Ooi, Poh Veh

2012-01-31

Secondary recurrent miscarriage (RM) is defined as three or more consecutive pregnancy losses after delivery of a viable infant. Previous reports suggest that a firstborn male child is associated with less favourable subsequent reproductive potential, possibly due to maternal immunisation against male-specific minor histocompatibility antigens. In a retrospective cohort study of 85 cases of secondary RM we aimed to determine if secondary RM was associated with (i) gender of previous child, maternal age, or duration of miscarriage history, and (ii) increased risk of pregnancy complications. Fifty-three women (62.0%; 53\\/85) gave birth to a male child prior to RM compared to 32 (38.0%; 32\\/85) who gave birth to a female child (p=0.002). The majority (91.7%; 78\\/85) had uncomplicated, term deliveries and normal birth weight neonates, with one quarter of the women previously delivered by Caesarean section. All had routine RM investigations and 19.0% (16\\/85) had an abnormal result. Fifty-seven women conceived again and 33.3% (19\\/57) miscarried, but there was no significant difference in failure rates between those with a previous male or female child (13\\/32 vs. 6\\/25, p=0.2). When patients with abnormal results were excluded, or when women with only one previous child were considered, there was still no difference in these rates. A previous male birth may be associated with an increased risk of secondary RM but numbers preclude concluding whether this increases recurrence risk. The suggested association with previous male birth provides a basis for further investigations at a molecular level.

Secondary recurrent miscarriage is associated with previous male birth.

LENUS (Irish Health Repository)

Ooi, Poh Veh

2011-01-01

Secondary recurrent miscarriage (RM) is defined as three or more consecutive pregnancy losses after delivery of a viable infant. Previous reports suggest that a firstborn male child is associated with less favourable subsequent reproductive potential, possibly due to maternal immunisation against male-specific minor histocompatibility antigens. In a retrospective cohort study of 85 cases of secondary RM we aimed to determine if secondary RM was associated with (i) gender of previous child, maternal age, or duration of miscarriage history, and (ii) increased risk of pregnancy complications. Fifty-three women (62.0%; 53\\/85) gave birth to a male child prior to RM compared to 32 (38.0%; 32\\/85) who gave birth to a female child (p=0.002). The majority (91.7%; 78\\/85) had uncomplicated, term deliveries and normal birth weight neonates, with one quarter of the women previously delivered by Caesarean section. All had routine RM investigations and 19.0% (16\\/85) had an abnormal result. Fifty-seven women conceived again and 33.3% (19\\/57) miscarried, but there was no significant difference in failure rates between those with a previous male or female child (13\\/32 vs. 6\\/25, p=0.2). When patients with abnormal results were excluded, or when women with only one previous child were considered, there was still no difference in these rates. A previous male birth may be associated with an increased risk of secondary RM but numbers preclude concluding whether this increases recurrence risk. The suggested association with previous male birth provides a basis for further investigations at a molecular level.

Case-control study for colorectal cancer genetic susceptibility in EPICOLON: previously identified variants and mucins

Directory of Open Access Journals (Sweden)

Moreno Victor

2011-08-01

Full Text Available Abstract Background Colorectal cancer (CRC is the second leading cause of cancer death in developed countries. Familial aggregation in CRC is also important outside syndromic forms and, in this case, a polygenic model with several common low-penetrance alleles contributing to CRC genetic predisposition could be hypothesized. Mucins and GALNTs (N-acetylgalactosaminyltransferase are interesting candidates for CRC genetic susceptibility and have not been previously evaluated. We present results for ten genetic variants linked to CRC risk in previous studies (previously identified category and 18 selected variants from the mucin gene family in a case-control association study from the Spanish EPICOLON consortium. Methods CRC cases and matched controls were from EPICOLON, a prospective, multicenter, nationwide Spanish initiative, comprised of two independent stages. Stage 1 corresponded to 515 CRC cases and 515 controls, whereas stage 2 consisted of 901 CRC cases and 909 controls. Also, an independent cohort of 549 CRC cases and 599 controls outside EPICOLON was available for additional replication. Genotyping was performed for ten previously identified SNPs in ADH1C, APC, CCDN1, IL6, IL8, IRS1, MTHFR, PPARG, VDR and ARL11, and 18 selected variants in the mucin gene family. Results None of the 28 SNPs analyzed in our study was found to be associated with CRC risk. Although four SNPs were significant with a P-value ADH1C (OR = 1.63, 95% CI = 1.06-2.50, P-value = 0.02, recessive, rs1800795 in IL6 (OR = 1.62, 95% CI = 1.10-2.37, P-value = 0.01, recessive, rs3803185 in ARL11 (OR = 1.58, 95% CI = 1.17-2.15, P-value = 0.007, codominant, and rs2102302 in GALNTL2 (OR = 1.20, 95% CI = 1.00-1.44, P-value = 0.04, log-additive 0, 1, 2 alleles], only rs3803185 achieved statistical significance in EPICOLON stage 2 (OR = 1.34, 95% CI = 1.06-1.69, P-value = 0.01, recessive. In the joint analysis for both stages, results were only significant for rs3803185 (OR = 1

Case-control study for colorectal cancer genetic susceptibility in EPICOLON: previously identified variants and mucins

International Nuclear Information System (INIS)

Abulí, Anna; Morillas, Juan D; Rigau, Joaquim; Latorre, Mercedes; Fernández-Bañares, Fernando; Peña, Elena; Riestra, Sabino; Payá, Artemio; Jover, Rodrigo; Xicola, Rosa M; Llor, Xavier; Fernández-Rozadilla, Ceres; Carvajal-Carmona, Luis; Villanueva, Cristina M; Moreno, Victor; Piqué, Josep M; Carracedo, Angel; Castells, Antoni; Andreu, Montserrat; Ruiz-Ponte, Clara; Castellví-Bel, Sergi; Alonso-Espinaco, Virginia; Muñoz, Jenifer; Gonzalo, Victoria; Bessa, Xavier; González, Dolors; Clofent, Joan; Cubiella, Joaquin

2011-01-01

Colorectal cancer (CRC) is the second leading cause of cancer death in developed countries. Familial aggregation in CRC is also important outside syndromic forms and, in this case, a polygenic model with several common low-penetrance alleles contributing to CRC genetic predisposition could be hypothesized. Mucins and GALNTs (N-acetylgalactosaminyltransferase) are interesting candidates for CRC genetic susceptibility and have not been previously evaluated. We present results for ten genetic variants linked to CRC risk in previous studies (previously identified category) and 18 selected variants from the mucin gene family in a case-control association study from the Spanish EPICOLON consortium. CRC cases and matched controls were from EPICOLON, a prospective, multicenter, nationwide Spanish initiative, comprised of two independent stages. Stage 1 corresponded to 515 CRC cases and 515 controls, whereas stage 2 consisted of 901 CRC cases and 909 controls. Also, an independent cohort of 549 CRC cases and 599 controls outside EPICOLON was available for additional replication. Genotyping was performed for ten previously identified SNPs in ADH1C, APC, CCDN1, IL6, IL8, IRS1, MTHFR, PPARG, VDR and ARL11, and 18 selected variants in the mucin gene family. None of the 28 SNPs analyzed in our study was found to be associated with CRC risk. Although four SNPs were significant with a P-value < 0.05 in EPICOLON stage 1 [rs698 in ADH1C (OR = 1.63, 95% CI = 1.06-2.50, P-value = 0.02, recessive), rs1800795 in IL6 (OR = 1.62, 95% CI = 1.10-2.37, P-value = 0.01, recessive), rs3803185 in ARL11 (OR = 1.58, 95% CI = 1.17-2.15, P-value = 0.007, codominant), and rs2102302 in GALNTL2 (OR = 1.20, 95% CI = 1.00-1.44, P-value = 0.04, log-additive 0, 1, 2 alleles], only rs3803185 achieved statistical significance in EPICOLON stage 2 (OR = 1.34, 95% CI = 1.06-1.69, P-value = 0.01, recessive). In the joint analysis for both stages, results were only significant for rs3803185 (OR = 1.12, 95% CI = 1

Origin of honeycombs: Testing the hydraulic and case hardening hypotheses

Science.gov (United States)

Bruthans, Jiří; Filippi, Michal; Slavík, Martin; Svobodová, Eliška

2018-02-01

Cavernous weathering (cavernous rock decay) is a global phenomenon, which occurs in porous rocks around the world. Although honeycombs and tafoni are considered to be the most common products of this complex process, their origin and evolution are as yet not fully understood. The two commonly assumed formation hypotheses - hydraulic and case hardening - were tested to elucidate the origin of honeycombs on sandstone outcrops in a humid climate. Mechanical and hydraulic properties of the lips (walls between adjacent pits) and backwalls (bottoms of pits) of the honeycombs were determined via a set of established and novel approaches. While the case hardening hypothesis was not supported by the determinations of either tensile strength, drilling resistance or porosity, the hydraulic hypothesis was clearly supported by field measurements and laboratory tests. Fluorescein dye visualization of capillary zone, vapor zone, and evaporation front upon their contact, demonstrated that the evaporation front reaches the honeycomb backwalls under low water flow rate, while the honeycomb lips remain dry. During occasional excessive water flow events, however, the evaporation front may shift to the lips, while the backwalls become moist as a part of the capillary zone. As the zone of evaporation corresponds to the zone of potential salt weathering, it is the spatial distribution of the capillary and vapor zones which dictates whether honeycombs are created or the rock surface is smoothed. A hierarchical model of factors related to the hydraulic field was introduced to obtain better insights into the process of cavernous weathering.

Science from evaluation: testing hypotheses about differential effects of three youth-focused suicide prevention trainings.

Science.gov (United States)

Coleman, Daniel; Del Quest, Aisling

2015-01-01

As part of an evaluation component of a youth suicide prevention, a quasi-experimental repeated measures design tested hypotheses about two brief suicide prevention gatekeeper trainings (Question, Persuade, Refer [QPR] and RESPONSE) and one longer suicide intervention skills training (Applied Suicide Intervention Skills Training [ASIST]). All three trainings showed large changes in prevention attitudes and self-efficacy, largely maintained at follow-up. ASIST trainees had large increases in asking at-risk youth about suicide at follow-up. Convergent with other research, modeling and role-play in training are crucial to increased prevention behaviors. Practice and research implications are discussed, including social work roles in suicide prevention and research.

Reoperative sentinel lymph node biopsy after previous mastectomy.

Science.gov (United States)

Karam, Amer; Stempel, Michelle; Cody, Hiram S; Port, Elisa R

2008-10-01

Sentinel lymph node (SLN) biopsy is the standard of care for axillary staging in breast cancer, but many clinical scenarios questioning the validity of SLN biopsy remain. Here we describe our experience with reoperative-SLN (re-SLN) biopsy after previous mastectomy. Review of the SLN database from September 1996 to December 2007 yielded 20 procedures done in the setting of previous mastectomy. SLN biopsy was performed using radioisotope with or without blue dye injection superior to the mastectomy incision, in the skin flap in all patients. In 17 of 20 patients (85%), re-SLN biopsy was performed for local or regional recurrence after mastectomy. Re-SLN biopsy was successful in 13 of 20 patients (65%) after previous mastectomy. Of the 13 patients, 2 had positive re-SLN, and completion axillary dissection was performed, with 1 having additional positive nodes. In the 11 patients with negative re-SLN, 2 patients underwent completion axillary dissection demonstrating additional negative nodes. One patient with a negative re-SLN experienced chest wall recurrence combined with axillary recurrence 11 months after re-SLN biopsy. All others remained free of local or axillary recurrence. Re-SLN biopsy was unsuccessful in 7 of 20 patients (35%). In three of seven patients, axillary dissection was performed, yielding positive nodes in two of the three. The remaining four of seven patients all had previous modified radical mastectomy, so underwent no additional axillary surgery. In this small series, re-SLN was successful after previous mastectomy, and this procedure may play some role when axillary staging is warranted after mastectomy.

Religiosity, Heavy Alcohol Use, and Vicarious Learning Networks among Adolescents in the United States

Science.gov (United States)

Gryczynski, Jan; Ward, Brian W.

2012-01-01

Previous research has found that religiosity may protect against risky alcohol and drug use behaviors among adolescents, but the social mechanics underpinning the relationship are not well understood. This study examined the relationship between religiosity, heavy drinking, and social norms among U.S. adolescents aged 12 to 17 years, using the…

Facial markings in the social cuckoo wasp Polistes sulcifer: No support for the visual deception and the assessment hypotheses.

Science.gov (United States)

Cini, Alessandro; Ortolani, Irene; Zechini, Luigi; Cervo, Rita

2015-02-01

Insect social parasites have to conquer a host colony by overcoming its defensive barriers. In addition to increased fighting abilities, many social parasites evolved sophisticated sensory deception mechanisms to elude host colonies defenses by exploiting host communication channels. Recently, it has been shown that the conspicuous facial markings of a paper wasp social parasite, Polistes sulcifer, decrease the aggressiveness of host foundresses. Two main hypotheses stand as explanations of this phenomenon: visual sensory deception (i.e. the black patterning reduces host aggression by exploiting the host visual communication system) and visual quality assessment (i.e. facial markings reduce aggressiveness as they signal the increased fighting ability of parasites). Through behavioral assays and morphological measurements we tested three predictions resulting from these hypotheses and found no support either for the visual sensory deception or for the quality assessment to explain the reduction in host aggressiveness towards the parasite. Our results suggest that other discrimination processes may explain the observed phenomenon. Copyright © 2014 Elsevier B.V. All rights reserved.

A Review of Hypothesized Determinants Associated with Bighorn Sheep (Ovis canadensis Die-Offs

Directory of Open Access Journals (Sweden)

David S. Miller

2012-01-01

Full Text Available Multiple determinants have been hypothesized to cause or favor disease outbreaks among free-ranging bighorn sheep (Ovis canadensis populations. This paper considered direct and indirect causes of mortality, as well as potential interactions among proposed environmental, host, and agent determinants of disease. A clear, invariant relationship between a single agent and field outbreaks has not yet been documented, in part due to methodological limitations and practical challenges associated with developing rigorous study designs. Therefore, although there is a need to develop predictive models for outbreaks and validated mitigation strategies, uncertainty remains as to whether outbreaks are due to endemic or recently introduced agents. Consequently, absence of established and universal explanations for outbreaks contributes to conflict among wildlife and livestock stakeholders over land use and management practices. This example illustrates the challenge of developing comprehensive models for understanding and managing wildlife diseases in complex biological and sociological environments.

Attachment and parental divorce: a test of the diffusion and sensitive period hypotheses.

Science.gov (United States)

Fraley, R Chris; Heffernan, Marie E

2013-09-01

One of the assumptions of attachment theory is that disruptions in parental relationships are prospectively related to insecure attachment patterns in adulthood. The majority of research that has evaluated this hypothesis, however, has been based on retrospective reports of the quality of relationships with parents-research that is subject to retrospective biases. In the present research, the authors examined the impact of parental divorce-an event that can be assessed relatively objectively-on attachment patterns in adulthood across two samples. The data indicate that parental divorce has selective rather than diffuse implications for insecure attachment. Namely, parental divorce was more strongly related to insecure relationships with parents in adulthood than insecure relationships with romantic partners or friends. In addition, parental insecurity was most pronounced when parental divorce took place in early childhood. This finding is consistent with hypotheses about sensitive periods in attachment development.

77 FR 70176 - Previous Participation Certification

Science.gov (United States)

2012-11-23

... participants' previous participation in government programs and ensure that the past record is acceptable prior... information is designed to be 100 percent automated and digital submission of all data and certifications is... government programs and ensure that the past record is acceptable prior to granting approval to participate...

Mismatch between aspects of hearing impairment and hearing disability/handicap in adult/elderly Cantonese speakers: some hypotheses concerning cultural and linguistic influences.

Science.gov (United States)

Doyle, J; Wong, L L

1996-12-01

This paper addresses the observation that some Cantonese-speaking adults do not perceive a hearing problem even when hearing screening identifies hearing loss. A sample of 49 Cantonese speakers was surveyed about their self-perceptions of hearing prior to a 25 dB HTL pure-tone screening test. All 49 persons failed the screening test, yet 34 (69.4%) reported that they had no problems hearing during conversations. Persons who admitted hearing difficulties tended to have mean hearing levels in excess of 45 dB HTL. A number of hypotheses concerning cultural and linguistic influences are proposed as explanations for the apparent lack of significance of auditory sensitivity loss for some Cantonese speakers. Ways in which these hypotheses might be tested are suggested.

Complementary Hypotheses on Contributors to the Obesity Epidemic.

Science.gov (United States)

Davis, Rachel A H; Plaisance, Eric P; Allison, David B

2018-01-01

Increased rates of obesity have occurred within virtually every race, age, sex, ethnicity, and economic group. Despite substantial punditry on the issue, the exact reasons are incompletely known. The two most common factors cited as contributing to the obesity epidemic, and those whose causal influence on increasing obesity levels in the population are often presumed unequivocally, are food marketing practices and institutionally driven reductions in physical activity. These have been called "the big two." This Perspective builds on previous writings in this area to introduce additional factors that may contribute to the obesity epidemic. It is emphasized that there may be other factors working in combination with the big two, influencing body fatness through effects on energy intake, energy expenditure, and/or nutrient partitioning. © 2017 The Obesity Society.

It could have been me: vicarious victims and disaster-focused distress.

Science.gov (United States)

Wayment, Heidi A

2004-04-01

College students who had experienced no personal bereavement in the September 11 terrorist attacks completed questionnaires between 3 and 5 weeks after the attacks and 5 months later. Cross-sectional and longitudinal structural equation model (SEM) analyses revealed that general distress and disaster-focused distress are discernable reactions following a collective loss. Both types of distress were higher among women and by those reporting social strain. General distress was associated with previous stressful events and mental health issues. Perceived similarity to the victims predicted disaster-focused distress and mediated the relationship between attending to media accounts of victims and disaster-focused distress. Only the disaster-focused distress reactions of survivor guilt and grief were associated with collective helping behaviors after the attacks and, for women, these behaviors were associated with greater reductions in these distress reactions over time. Discussion focuses on the importance of examining disaster-focused distress reactions following collective loss.

[Prevalence of previously diagnosed diabetes mellitus in Mexico.

Science.gov (United States)

Rojas-Martínez, Rosalba; Basto-Abreu, Ana; Aguilar-Salinas, Carlos A; Zárate-Rojas, Emiliano; Villalpando, Salvador; Barrientos-Gutiérrez, Tonatiuh

2018-01-01

To compare the prevalence of previously diagnosed diabetes in 2016 with previous national surveys and to describe treatment and its complications. Mexico's national surveys Ensa 2000, Ensanut 2006, 2012 and 2016 were used. For 2016, logistic regression models and measures of central tendency and dispersion were obtained. The prevalence of previously diagnosed diabetes in 2016 was 9.4%. The increase of 2.2% relative to 2012 was not significant and only observed in patients older than 60 years. While preventive measures have increased, the access to medical treatment and lifestyle has not changed. The treatment has been modified, with an increase in insulin and decrease in hypoglycaemic agents. Population aging, lack of screening actions and the increase in diabetes complications will lead to an increase on the burden of disease. Policy measures targeting primary and secondary prevention of diabetes are crucial.

Recruitment processes in Baltic sprat - A re-evaluation of GLOBEC Germany hypotheses

Science.gov (United States)

Voss, Rüdiger; Peck, Myron A.; Hinrichsen, Hans-Harald; Clemmesen, Catriona; Baumann, Hannes; Stepputtis, Daniel; Bernreuther, Matthias; Schmidt, Jörn O.; Temming, Axel; Köster, Fritz W.

2012-12-01

The GLOBEC Germany program (2002-2007) had the ambitious goal to resolve the processes impacting the recruitment dynamics of Baltic sprat (Sprattus sprattus L.) by examining various factors affecting early life history stages. At the start of the research program, a number of general recruitment hypotheses were formulated, i.e. focusing on (1) predation, (2) food availability, (3) physical parameters, (4) the impact of current systems, and finally (5) the importance of top-down vs bottom-up effects. The present study synthesizes the results of field sampling (2002 and 2003), laboratory experiments, and modeling studies to re-evaluate these hypotheses for the Baltic sprat stock. Recruitment success was quite different in the 2 years investigated. Despite a lower spawning stock biomass in 2003, the total number of recruits was almost 2-fold higher that year compared to 2002. The higher recruitment success in 2003 could be attributed to enhanced survival success during the post-larval/juvenile stage, a life phase that appears to be critical for recruitment dynamics. In the state of the Baltic ecosystem during the period of investigation, we consider bottom-up control (e.g. temperature, prey abundance) to be more important than top-down control (predation mortality). This ranking in importance does not vary seasonally. Prevailing water circulation patterns and the transport dynamics of larval cohorts have a strong influence on sprat recruitment success. Pronounced transport to coastal areas is detrimental for year-class strength particularly at high sprat stock sizes. A suggested mechanism is density-dependant regulation of survival via intra- and inter-specific competition for prey in coastal areas. A documented change in larval vertical migration behavior between the early 1990s and early 2000s increased the transport potential to the coast, strengthening the coupling between inter-annual differences in the magnitude and direction of wind-driven surface currents and

Intention to breastfeed in low-income pregnant women: the role of social support and previous experience.

Science.gov (United States)

Humphreys, A S; Thompson, N J; Miner, K R

1998-09-01

The purpose of this study was to describe the relationship between breastfeeding intention among socioeconomically disadvantaged pregnant women and maternal demographics, previous breastfeeding experience, and social support. A cross-sectional, convenience sampling strategy was employed for data collection. Low-income women (n = 1001) in a public hospital completed a six-page questionnaire about their infant feeding plans, demographics, and social support. Simple regression analyses were conducted to compare maternal breastfeeding intention with the hypothesized correlates. Breastfeeding intention was positively correlated with older maternal age, higher education, more breastfeeding experience, Hispanic ethnicity, and hearing about breastfeeding benefits from family members, the baby's father, and lactation consultants, but not from other health professionals. Health professionals' attitudes were less influential on women's infant feeding decisions than the attitudes and beliefs of members of women's social support networks. When controlling for breastfeeding experience (none vs any), some findings, varied, indicating a need for breastfeeding interventions tailored to women's level of experience. Use of peer counselors and lactation consultants, inclusion of a woman's family members in breastfeeding educational contacts, and creation of breastfeeding classes tailored to influential members of women's social support networks may improve breastfeeding rates among low-income women, especially those with no breastfeeding experience, more effectively than breastfeeding education to pregnant women that is solely conducted by health professionals.

How do trees die? A test of the hydraulic failure and carbon starvation hypotheses

Science.gov (United States)

Sevanto, Sanna; Mcdowell, Nate G; Dickman, L Turin; Pangle, Robert; Pockman, William T

2014-01-01

Despite decades of research on plant drought tolerance, the physiological mechanisms by which trees succumb to drought are still under debate. We report results from an experiment designed to separate and test the current leading hypotheses of tree mortality. We show that piñon pine (Pinus edulis) trees can die of both hydraulic failure and carbon starvation, and that during drought, the loss of conductivity and carbohydrate reserves can also co-occur. Hydraulic constraints on plant carbohydrate use determined survival time: turgor loss in the phloem limited access to carbohydrate reserves, but hydraulic control of respiration prolonged survival. Our data also demonstrate that hydraulic failure may be associated with loss of adequate tissue carbohydrate content required for osmoregulation, which then promotes failure to maintain hydraulic integrity. PMID:23730972

Testing Cort-Fitness and Cort-Adaptation hypotheses in a habitat suitability gradient for roe deer

Science.gov (United States)

Escribano-Avila, Gema; Pettorelli, Nathalie; Virgós, Emilio; Lara-Romero, Carlos; Lozano, Jorge; Barja, Isabel; Cuadra, Felipe S.; Puerta, Marisa

2013-11-01

According to the Cort-Fitness Hypothesis, higher stress levels (glucocorticoids) in vertebrates are correlated to lower fitness. However, recent studies have failed to validate this hypothesis. A proposed wider framework suggests that reproduction can be perceived as an overload adds up to other environmental challenges that individuals must adjust to. In this case, elevated glucocorticoids could help individuals to allocate resources to reproduction without comprising other functions, leading to the expectation of a positive cort-fitness relationship. This has been proposed as the Cort-Adaptation Hypothesis. Stress levels result from a complex interaction between the environment and the neuroendocrine system of animals. Accounting for physiological functions involved in how animals cope with their environment would help to clarify the relationship between glucocorticoids and animal performance. We used roe deer (Capreolus capreolus) inhabiting diverse habitats in the Iberian Peninsula to: i) test the Cort-Fitness and Cort-Adaptation hypotheses by indexing fitness using a comprehensive physiological approach which takes into account fundamental physiological functions and their trade-offs; and ii) evaluate the link between primary productivity and individuals' condition in a seasonal environment. We evaluated spatial and temporal variation in stress levels, reproductive hormone levels, nutritional status and immune function from fecal samples collected in 2010. Lower stress levels were related to better condition in non-reproductive seasons but not to higher primary productivity. In contrast, stress levels were always positively related to reproductive condition, which was better in most productive habitats. Summer and winter were the less productive seasons and the more challenging for the species in the habitat gradient studied. In winter, reproductive condition traded off against immune function being biased toward immune function in less productive habitats. In

Computer-mediated communication and interpersonal attraction: an experimental test of two explanatory hypotheses.

Science.gov (United States)

Antheunis, Marjolijn L; Valkenburg, Patti M; Peter, Jochen

2007-12-01

The aims of this study were (a) to investigate the influence of computer-mediated communication (CMC) on interpersonal attraction and (b) to examine two underlying processes in the CMC-interpersonal attraction relationship. We identified two variables that may mediate the influence of CMC on interpersonal attraction: self-disclosure and direct questioning. Focusing on these potential mediating variables, we tested two explanatory hypotheses: the CMC-induced direct questioning hypothesis and the CMC-induced self-disclosure hypothesis. Eighty-one cross-sex dyads were randomly assigned to one of three experimental conditions: text-only CMC, visual CMC, and face-to-face communication. We did not find a direct effect of CMC on interpersonal attraction. However, we did find two positive indirect effects of text-only CMC on interpersonal attraction: text-only CMC stimulated both self-disclosure and direct questioning, both of which in turn enhanced interpersonal attraction. Results are discussed in light of uncertainty reduction theory and CMC theories.

An Attempt to Determine the Construct Validity of Measures Hypothesized to Represent an Orientation to Right, Left, or Integrated Hemispheric Brain Function for a Sample of Primary School Children.

Science.gov (United States)

Dumbrower, Jule; And Others

1981-01-01

This study attempts to obtain evidence of the construct validity of pupil ability tests hypothesized to represent orientation to right, left, or integrated hemispheric function, and of teacher observation subscales intended to reveal behaviors in school setting that were hypothesized to portray preference for right or left brain function. (Author)

75 FR 76056 - FEDERAL REGISTER CITATION OF PREVIOUS ANNOUNCEMENT:

Science.gov (United States)

2010-12-07

... SECURITIES AND EXCHANGE COMMISSION Sunshine Act Meeting FEDERAL REGISTER CITATION OF PREVIOUS ANNOUNCEMENT: STATUS: Closed meeting. PLACE: 100 F Street, NE., Washington, DC. DATE AND TIME OF PREVIOUSLY ANNOUNCED MEETING: Thursday, December 9, 2010 at 2 p.m. CHANGE IN THE MEETING: Time change. The closed...

Teaching the Fluctuation Test "In Silico" by Using Mutate: A Program to Distinguish between the Adaptive and Spontaneous Mutation Hypotheses

Science.gov (United States)

Carvajal-Rodriguez, Antonio

2012-01-01

Mutate is a program developed for teaching purposes to impart a virtual laboratory class for undergraduate students of Genetics in Biology. The program emulates the so-called fluctuation test whose aim is to distinguish between spontaneous and adaptive mutation hypotheses in bacteria. The plan is to train students in certain key multidisciplinary…

Identifying World Views Projected by Science Teaching Materials: A Case Study Using Pepper's WORLD HYPOTHESES to Analyze a Biology Textbook.

Science.gov (United States)

Kilbourn, Brent

The purpose of this study is to develop and demonstrate the use of a conceptual framework for assessing the potential of "world view" as a concept for understanding important issues in science education. The framework is based on Stephen C. Pepper's treatment of six world hypotheses (animism, mysticism, formism, mechansim, contextualism, and…

Implant breast reconstruction after salvage mastectomy in previously irradiated patients.

Science.gov (United States)

Persichetti, Paolo; Cagli, Barbara; Simone, Pierfranco; Cogliandro, Annalisa; Fortunato, Lucio; Altomare, Vittorio; Trodella, Lucio

2009-04-01

The most common surgical approach in case of local tumor recurrence after quadrantectomy and radiotherapy is salvage mastectomy. Breast reconstruction is the subsequent phase of the treatment and the plastic surgeon has to operate on previously irradiated and manipulated tissues. The medical literature highlights that breast reconstruction with tissue expanders is not a pursuable option, considering previous radiotherapy a contraindication. The purpose of this retrospective study is to evaluate the influence of previous radiotherapy on 2-stage breast reconstruction (tissue expander/implant). Only patients with analogous timing of radiation therapy and the same demolitive and reconstructive procedures were recruited. The results of this study prove that, after salvage mastectomy in previously irradiated patients, implant reconstruction is still possible. Further comparative studies are, of course, advisable to draw any conclusion on the possibility to perform implant reconstruction in previously irradiated patients.

28 CFR 10.5 - Incorporation of papers previously filed.

Science.gov (United States)

2010-07-01

... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Incorporation of papers previously filed... CARRYING ON ACTIVITIES WITHIN THE UNITED STATES Registration Statement § 10.5 Incorporation of papers previously filed. Papers and documents already filed with the Attorney General pursuant to the said act and...

Recruitment processes in Baltic sprat - A re-evaluation of GLOBEC Germany hypotheses

DEFF Research Database (Denmark)

Voss, Rudiger; Peck, M.A.; Hinrichsen, H.-H.

2012-01-01

The GLOBEC Germany program (2002–2007) had the ambitious goal to resolve the processes impacting the recruitment dynamics ofBalticsprat (Sprattus sprattus L.) by examining various factors affecting early life history stages. At the start of the research program, a number of general recruitmenthyp......The GLOBEC Germany program (2002–2007) had the ambitious goal to resolve the processes impacting the recruitment dynamics ofBalticsprat (Sprattus sprattus L.) by examining various factors affecting early life history stages. At the start of the research program, a number of general......, and modeling studies to re-evaluate these hypotheses for the Balticsprat stock. Recruitment success was quite different in the 2 years investigated. Despite a lower spawning stock biomass in 2003, the total number of recruits was almost 2-fold higher that year compared to 2002. The higher recruitment success...... in 2003 could be attributed to enhanced survival success during the post-larval/juvenile stage, a life phase that appears to be critical for recruitment dynamics. In the state of the Baltic ecosystem during the period of investigation, we consider bottom-up control (e.g. temperature, prey abundance...

A DNA and morphology based phylogenetic framework of the ant genus Lasius with hypotheses for the evolution of social parasitism and fungiculture.

Science.gov (United States)

Maruyama, Munetoshi; Steiner, Florian M; Stauffer, Christian; Akino, Toshiharu; Crozier, Ross H; Schlick-Steiner, Birgit C

2008-08-19

Ants of the genus Lasius are ecologically important and an important system for evolutionary research. Progress in evolutionary research has been hindered by the lack of a well-founded phylogeny of the subgenera, with three previous attempts disagreeing. Here we employed two mitochondrial genes (cytochrome c oxidase subunit I, 16S ribosomal RNA), comprising 1,265 bp, together with 64 morphological characters, to recover the phylogeny of Lasius by Bayesian and Maximum Parsimony inference after exploration of potential causes of phylogenetic distortion. We use the resulting framework to infer evolutionary pathways for social parasitism and fungiculture. We recovered two well supported major lineages. One includes Acanthomyops, Austrolasius, Chthonolasius, and Lasius pallitarsis, which we confirm to represent a seventh subgenus, the other clade contains Dendrolasius, and Lasius sensu stricto. The subgenus Cautolasius, displaying neither social parasitism nor fungiculture, probably belongs to the second clade, but its phylogenetic position is not resolved at the cutoff values of node support we apply. Possible causes for previous problems with reconstructing the Lasius phylogeny include use of other reconstruction techniques, possibly more prone to instabilities in some instances, and the inclusion of phylogenetically distorting characters. By establishing an updated phylogenetic framework, our study provides the basis for a later formal taxonomic revision of subgenera and for studying the evolution of various ecologically and sociobiologically relevant traits of Lasius, although there is need for future studies to include nuclear genes and additional samples from the Nearctic. Both social parasitism and fungiculture evolved twice in Lasius, once in each major lineage, which opens up new opportunities for comparative analyses. The repeated evolution of social parasitism has been established for other groups of ants, though not for temporary social parasitism as found

Phylogeography of Buddleja crispa (Buddlejaceae) and its correlation with drainage system evolution in southwestern China.

Science.gov (United States)

Yue, Liang-Liang; Chen, Gao; Sun, Wei-Bang; Sun, Hang

2012-10-01

Southwestern China is an area of active tectonism and erosion, yielding a dynamic, deeply eroded landscape that is hypothesized to have influenced the genetic structure of the resident populations of plants and animals. However, few studies have been conducted to examine the influence of changing river channels, particularly in the Yarlung Tsangpo area, on genetic distributions in plants. We here examine the population structure of Buddleja crispa, a dominant element of the dry, warm/hot river-valley communities, seeking to delimit the current population genetic structure and its relation to past changes in the courses of the major rivers in this area. • Two chloroplast DNA fragments were used to estimate the genetic variation and phylogeographic structure of the populations, and to infer nested clades, of the species. • We detected low intrapopulational haplotype diversity and higher overall population haplotype diversity (h(S) = 0.085, h(T) = 0.781). Molecular variance was mainly observed between groups (81.42%). Robust population genetic structure were detected by AMOVA (F(ST) = 0.967), coinciding with three nested clades (identified by NCPA) and five phylo-groups linked with paleo-drainage systems (identified by SAMOVA). No support for extensive spatial or demographical expansion was obtained. • A general pattern of genetic isolation by vicariance was inferred, and detected disjunct patterns strongly indicate that currently discontinuous drainage systems were historically linked. Most importantly, population subdivisions and genetic variation perfectly reflect the putative Paleo-Red-River drainage pattern, and Yarlung Tsangpo populations are closely related to Central Yunnan Plateau populations, indicating that they were previously connected by ancient river courses. Divergence times between these river systems estimated by molecular dating (in the Pleistocene) agree with previous findings.

Phylogeny of Gobioidei and the origin of European gobies

Directory of Open Access Journals (Sweden)

Ainhoa Agorreta

2015-11-01

Full Text Available The percomorph order Gobioidei comprises over 2200 species worldwide distributed that occupy most freshwater, brackish and marine environments, and show a spectacular variety in morphology, ecology, and behaviour. However, phylogenetic relationships among many gobioid groups still remain poorly understood. Such is the case of Gobiidae, a rapidly radiating lineage that encompass an unusually high diversity of species (nearly 2000, including the largely endemic European species whose origin and ancestry remain uncertain. The resolution and accuracy of previous molecular phylogenetic studies has been limited due to the use of only a few (generally mitochondrial molecular markers and/or the absence of representatives of several key lineages. Our study (built on Agorreta et al. 2013 is the first to include multiple nuclear and mitochondrial genes for nearly 300 terminal taxa representing the vast diversity of gobioid lineages. We have used this information to reconstruct a robust phylogeny of Gobioidei, and we are now investigating the historical biogeography and diversification times of European gobies with a time-calibrated molecular phylogeny. Robustness of the inferred phylogenetic trees is significantly higher than that of previous studies, hence providing the most compelling molecular phylogenetic hypotheses for Gobioidei thus far. The family Eleotrididae branches off the gobioid tree after the Rhyacichthyidae + Odontobutidae clade followed by the Butidae as the sister-group of the Gobiidae. Several monophyletic groups are identified within the two major Gobiidae subclades, the gobionelline-like and the gobiine-like gobiids. The European gobies cluster in three distinct lineages (Pomatoschistus-, Aphia-, and Gobius-lineages, each with different affinities with gobiids from the Indo-Pacific and perhaps the New World. Our ongoing more-detailed study on European gobies will reveal whether their origin is related to vicariant events linked to the

No discrimination against previous mates in a sexually cannibalistic spider

Science.gov (United States)

Fromhage, Lutz; Schneider, Jutta M.

2005-09-01

In several animal species, females discriminate against previous mates in subsequent mating decisions, increasing the potential for multiple paternity. In spiders, female choice may take the form of selective sexual cannibalism, which has been shown to bias paternity in favor of particular males. If cannibalistic attacks function to restrict a male's paternity, females may have little interest to remate with males having survived such an attack. We therefore studied the possibility of female discrimination against previous mates in sexually cannibalistic Argiope bruennichi, where females almost always attack their mate at the onset of copulation. We compared mating latency and copulation duration of males having experienced a previous copulation either with the same or with a different female, but found no evidence for discrimination against previous mates. However, males copulated significantly shorter when inserting into a used, compared to a previously unused, genital pore of the female.

“Liking” and “Wanting” Linked to Reward Deficiency Syndrome (RDS): Hypothesizing Differential Responsivity in Brain Reward Circuitry

OpenAIRE

Blum, Kenneth; Gardner, Eliot; Oscar-Berman, Marlene; Gold, Mark

2012-01-01

In an attempt to resolve controversy regarding the causal contributions of mesolimbic dopamine (DA) systems to reward, we evaluate the three main competing explanatory categories: “liking,” “learning,” and “wanting” [1]. That is, DA may mediate (a) the hedonic impact of reward (liking), (b) learned predictions about rewarding effects (learning), or (c) the pursuit of rewards by attributing incentive salience to reward-related stimuli (wanting). We evaluate these hypotheses, especially as they...

Littoral cell angioma of the spleen in a patient with previous pulmonary sarcoidosis: a TNF-α related pathogenesis?

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Titze Ulf

2011-09-01

Full Text Available Abstract Background Littoral cell angioma (LCA is a rare vascular tumor of the spleen. Generally thought to be benign, additional cases of LCA with malignant features have been described. Thus, its malignant potential seems to vary and must be considered uncertain. The etiology remains unclear, but an immune dysregulation for the apparent association with malignancies of visceral organs or immune-mediated diseases has been proposed. Case Presentation We report a case of LCA in a 43-year old male patient who presented with a loss of appetite and intermittent upper abdominal pain. Computed tomography showed multiple hypoattenuating splenic lesions which were hyperechogenic on abdominal ultrasound. Lymphoma was presumed and splenectomy was performed. Pathological evaluation revealed LCA. Conclusions LCA is a rare, primary vascular neoplasm of the spleen that might etiologically be associated with immune dysregulation. In addition, it shows a striking association with synchronous or prior malignancies. With about one-third of the reported cases to date being co-existent with malignancies of visceral organs or immune-mediated diseases, this advocates for close follow-ups in all patients diagnosed with LCA. To our knowledge, this report is the first one of LCA associated with previous pulmonary sarcoidosis and hypothesizes a TNF-α related pathogenesis of this splenic tumor.

A previous hamstring injury affects kicking mechanics in soccer players.

Science.gov (United States)

Navandar, Archit; Veiga, Santiago; Torres, Gonzalo; Chorro, David; Navarro, Enrique

2018-01-10

Although the kicking skill is influenced by limb dominance and sex, how a previous hamstring injury affects kicking has not been studied in detail. Thus, the objective of this study was to evaluate the effect of sex and limb dominance on kicking in limbs with and without a previous hamstring injury. 45 professional players (males: n=19, previously injured players=4, age=21.16 ± 2.00 years; females: n=19, previously injured players=10, age=22.15 ± 4.50 years) performed 5 kicks each with their preferred and non-preferred limb at a target 7m away, which were recorded with a three-dimensional motion capture system. Kinematic and kinetic variables were extracted for the backswing, leg cocking, leg acceleration and follow through phases. A shorter backswing (20.20 ± 3.49% vs 25.64 ± 4.57%), and differences in knee flexion angle (58 ± 10o vs 72 ± 14o) and hip flexion velocity (8 ± 0rad/s vs 10 ± 2rad/s) were observed in previously injured, non-preferred limb kicks for females. A lower peak hip linear velocity (3.50 ± 0.84m/s vs 4.10 ± 0.45m/s) was observed in previously injured, preferred limb kicks of females. These differences occurred in the backswing and leg-cocking phases where the hamstring muscles were the most active. A variation in the functioning of the hamstring muscles and that of the gluteus maximus and iliopsoas in the case of a previous injury could account for the differences observed in the kicking pattern. Therefore, the effects of a previous hamstring injury must be considered while designing rehabilitation programs to re-educate kicking movement.

Subsequent childbirth after a previous traumatic birth.

Science.gov (United States)

Beck, Cheryl Tatano; Watson, Sue

2010-01-01

Nine percent of new mothers in the United States who participated in the Listening to Mothers II Postpartum Survey screened positive for meeting the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for posttraumatic stress disorder after childbirth. Women who have had a traumatic birth experience report fewer subsequent children and a longer length of time before their second baby. Childbirth-related posttraumatic stress disorder impacts couples' physical relationship, communication, conflict, emotions, and bonding with their children. The purpose of this study was to describe the meaning of women's experiences of a subsequent childbirth after a previous traumatic birth. Phenomenology was the research design used. An international sample of 35 women participated in this Internet study. Women were asked, "Please describe in as much detail as you can remember your subsequent pregnancy, labor, and delivery following your previous traumatic birth." Colaizzi's phenomenological data analysis approach was used to analyze the stories of the 35 women. Data analysis yielded four themes: (a) riding the turbulent wave of panic during pregnancy; (b) strategizing: attempts to reclaim their body and complete the journey to motherhood; (c) bringing reverence to the birthing process and empowering women; and (d) still elusive: the longed-for healing birth experience. Subsequent childbirth after a previous birth trauma has the potential to either heal or retraumatize women. During pregnancy, women need permission and encouragement to grieve their prior traumatic births to help remove the burden of their invisible pain.

Coming to America: multiple origins of New World geckos.

Science.gov (United States)

Gamble, T; Bauer, A M; Colli, G R; Greenbaum, E; Jackman, T R; Vitt, L J; Simons, A M

2011-02-01

Geckos in the Western Hemisphere provide an excellent model to study faunal assembly at a continental scale. We generated a time-calibrated phylogeny, including exemplars of all New World gecko genera, to produce a biogeographical scenario for the New World geckos. Patterns of New World gecko origins are consistent with almost every biogeographical scenario utilized by a terrestrial vertebrate with different New World lineages showing evidence of vicariance, dispersal via temporary land bridge, overseas dispersal or anthropogenic introductions. We also recovered a strong relationship between clade age and species diversity, with older New World lineages having more species than more recently arrived lineages. Our data provide the first phylogenetic hypothesis for all New World geckos and highlight the intricate origins and ongoing organization of continental faunas. The phylogenetic and biogeographical hypotheses presented here provide an historical framework to further pursue research on the diversification and assembly of the New World herpetofauna. © 2010 The Authors. Journal of Evolutionary Biology © 2010 European Society For Evolutionary Biology.

On the particular vulnerability of face recognition to aging: A review of three hypotheses

Directory of Open Access Journals (Sweden)

Isabelle eBoutet

2015-08-01

Full Text Available Age-related face recognition deficits are characterized by high false alarms to unfamiliar faces, are not as pronounced for other complex stimuli, and are only partially related to general age-related impairments in cognition. This paper reviews some of the underlying processes likely to be implicated in theses deficits by focusing on areas where contradictions abound as a means to highlight avenues for future research. Research pertaining to three following hypotheses is presented: (i perceptual deterioration, (ii encoding of configural information, and (iii difficulties in recollecting contextual information. The evidence surveyed provides support for the idea that all three factors are likely to contribute, under certain conditions, to the deficits in face recognition seen in older adults. We discuss how these different factors might interact in the context of a generic framework of the different stages implicated in face recognition. Several suggestions for future investigations are outlined.

Sexual videos in Internet: a test of 11 hypotheses about intimate practices and gender interactions in Latin America

OpenAIRE

Monge-Nájera, Julián; Corrales, Karla Vega

2015-01-01

There is a marked lack of literature on user-submitted sexual videos from Latin America. To start filling that gap, we present a formal statistical testing of several hypotheses about the characteristics of 214 videos from Nereliatube.com posted from the inauguration of the site until December 2010. We found that in most cases the video was made consensually and the camera was operated by the man. The most frequent practice shown was fellatio, followed by vaginal penetration.  The great major...

Contrasting microbial community assembly hypotheses: a reconciling tale from the Río Tinto.

Science.gov (United States)

Palacios, Carmen; Zettler, Erik; Amils, Ricardo; Amaral-Zettler, Linda

2008-01-01

The Río Tinto (RT) is distinguished from other acid mine drainage systems by its natural and ancient origins. Microbial life from all three domains flourishes in this ecosystem, but bacteria dominate metabolic processes that perpetuate environmental extremes. While the patchy geochemistry of the RT likely influences the dynamics of bacterial populations, demonstrating which environmental variables shape microbial diversity and unveiling the mechanisms underlying observed patterns, remain major challenges in microbial ecology whose answers rely upon detailed assessments of community structures coupled with fine-scale measurements of physico-chemical parameters. By using high-throughput environmental tag sequencing we achieved saturation of richness estimators for the first time in the RT. We found that environmental factors dictate the distribution of the most abundant taxa in this system, but stochastic niche differentiation processes, such as mutation and dispersal, also contribute to observed diversity patterns. We predict that studies providing clues to the evolutionary and ecological processes underlying microbial distributions will reconcile the ongoing debate between the Baas Becking vs. Hubbell community assembly hypotheses.

Contrasting microbial community assembly hypotheses: a reconciling tale from the Río Tinto.

Directory of Open Access Journals (Sweden)

Carmen Palacios

Full Text Available The Río Tinto (RT is distinguished from other acid mine drainage systems by its natural and ancient origins. Microbial life from all three domains flourishes in this ecosystem, but bacteria dominate metabolic processes that perpetuate environmental extremes. While the patchy geochemistry of the RT likely influences the dynamics of bacterial populations, demonstrating which environmental variables shape microbial diversity and unveiling the mechanisms underlying observed patterns, remain major challenges in microbial ecology whose answers rely upon detailed assessments of community structures coupled with fine-scale measurements of physico-chemical parameters.By using high-throughput environmental tag sequencing we achieved saturation of richness estimators for the first time in the RT. We found that environmental factors dictate the distribution of the most abundant taxa in this system, but stochastic niche differentiation processes, such as mutation and dispersal, also contribute to observed diversity patterns.We predict that studies providing clues to the evolutionary and ecological processes underlying microbial distributions will reconcile the ongoing debate between the Baas Becking vs. Hubbell community assembly hypotheses.

Previously unknown species of Aspergillus.

Science.gov (United States)

Gautier, M; Normand, A-C; Ranque, S

2016-08-01

The use of multi-locus DNA sequence analysis has led to the description of previously unknown 'cryptic' Aspergillus species, whereas classical morphology-based identification of Aspergillus remains limited to the section or species-complex level. The current literature highlights two main features concerning these 'cryptic' Aspergillus species. First, the prevalence of such species in clinical samples is relatively high compared with emergent filamentous fungal taxa such as Mucorales, Scedosporium or Fusarium. Second, it is clearly important to identify these species in the clinical laboratory because of the high frequency of antifungal drug-resistant isolates of such Aspergillus species. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) has recently been shown to enable the identification of filamentous fungi with an accuracy similar to that of DNA sequence-based methods. As MALDI-TOF MS is well suited to the routine clinical laboratory workflow, it facilitates the identification of these 'cryptic' Aspergillus species at the routine mycology bench. The rapid establishment of enhanced filamentous fungi identification facilities will lead to a better understanding of the epidemiology and clinical importance of these emerging Aspergillus species. Based on routine MALDI-TOF MS-based identification results, we provide original insights into the key interpretation issues of a positive Aspergillus culture from a clinical sample. Which ubiquitous species that are frequently isolated from air samples are rarely involved in human invasive disease? Can both the species and the type of biological sample indicate Aspergillus carriage, colonization or infection in a patient? Highly accurate routine filamentous fungi identification is central to enhance the understanding of these previously unknown Aspergillus species, with a vital impact on further improved patient care. Copyright © 2016 European Society of Clinical Microbiology and

Capitalizing on Citizen Science Data for Validating Models and Generating Hypotheses Describing Meteorological Drivers of Mosquito-Borne Disease Risk

Science.gov (United States)

Boger, R. A.; Low, R.; Paull, S.; Anyamba, A.; Soebiyanto, R. P.

2017-12-01

Temperature and precipitation are important drivers of mosquito population dynamics, and a growing set of models have been proposed to characterize these relationships. Validation of these models, and development of broader theories across mosquito species and regions could nonetheless be improved by comparing observations from a global dataset of mosquito larvae with satellite-based measurements of meteorological variables. Citizen science data can be particularly useful for two such aspects of research into the meteorological drivers of mosquito populations: i) Broad-scale validation of mosquito distribution models and ii) Generation of quantitative hypotheses regarding changes to mosquito abundance and phenology across scales. The recently released GLOBE Observer Mosquito Habitat Mapper (GO-MHM) app engages citizen scientists in identifying vector taxa, mapping breeding sites and decommissioning non-natural habitats, and provides a potentially useful new tool for validating mosquito ubiquity projections based on the analysis of remotely sensed environmental data. Our early work with GO-MHM data focuses on two objectives: validating citizen science reports of Aedes aegypti distribution through comparison with accepted scientific data sources, and exploring the relationship between extreme temperature and precipitation events and subsequent observations of mosquito larvae. Ultimately the goal is to develop testable hypotheses regarding the shape and character of this relationship between mosquito species and regions.

22 CFR 40.93 - Aliens unlawfully present after previous immigration violation.

Science.gov (United States)

2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Aliens unlawfully present after previous... TO BOTH NONIMMIGRANTS AND IMMIGRANTS UNDER THE IMMIGRATION AND NATIONALITY ACT, AS AMENDED Aliens Previously Removed § 40.93 Aliens unlawfully present after previous immigration violation. An alien described...

How the mainstream limits the spreading of alternative hypotheses

Science.gov (United States)

Kalenda, Pavel

2014-05-01

that prof. Djuric had tried for more than 10 years to publish this article in various peer-reviewed journals. So, prof. Djuric got into the official book (list) of "scientific dissidents" among hundreds of other professors and doctors of science (De Climont 2012). These "scientific dissidents" do not have access to established journals and may possibly publish privately or at best on the web in marginal journals whose list was published by De Climont (2012). Such a marginal journal in the field of geophysics and geology is New Concepts in Global Tectonics. This journal has been established because the current hypothesis about the movement of the continents due to convection currents in the mantle becomes under the weight of new observation quite untenable. 4) Scientific consensus History has known many hypotheses that were accepted as proven truth but later, in the light of new knowledge, they completely failed. - No one has the right to decide which scientific hypotheses will be accepted and which will not get into print. Perhaps the worst situation is in climatology (due to global effects and impacts), when the plenary session of IPCC consensually stated that the current global warming was mainly due to the human activity. References De Climont, J. (2012): The worldwide list of dissident scientists. http://astrojan.hostei.com/droa.htm. Djurič, J. (2006): Unification Of Gravitation And Electromagnetism. http://jovandjuric.tripod.com/ David H. Douglass, John R. Christy, Benjamin D. Pearson and S. Fred Singer (2007): A comparison of tropical temperature trends with model predictions. International Journal of Climatology, Volume 28, Issue 13, 15 November 2008, Pages: 1693-1701. http://onlinelibrary.wiley.com/doi/10.1002/joc.1651/pdf. Einstein, A. : List of scientific publications by Albert Einstein. /wiki/List_of_scientific_publications_by_Albert_Einstein. Kolínský, P., Valenta, J. and Gaždová, R. (2012): Seismicity, groundwater level variations and earth tides in

GnRH Neurons on LSD: A Year of Rejecting Hypotheses That May Have Made Karl Popper Proud.

Science.gov (United States)

Moenter, Suzanne M

2018-01-01

Gonadotropin-releasing hormone (GnRH) neurons are critical to many aspects of fertility regulation, from producing episodic release critical to both sexes, to providing a central signal to induce the ovulatory cascade in females. This year saw progress through the rejection, and occasional support, of hypotheses in understanding how GnRH neurons contribute to these processes. This brief review provides one laboratory's view of new insights into possible roles for these cells in development, adult reproductive function, and what may go wrong with GnRH neurons in some cases of infertility. Copyright © 2018 Endocrine Society.

Distinguishing 'Higgs' spin hypotheses using γγ and WW* decays

International Nuclear Information System (INIS)

Ellis, John; Fok, Ricky; Hwang, Dae Sung; Sanz, Veronica; You, Tevong

2013-01-01

The new particle X recently discovered by the ATLAS and CMS Collaborations in searches for the Higgs boson has been observed to decay into γγ, ZZ * and WW * , but its spin and parity, J P , remain a mystery, with J P = 0 + and 2 + being open possibilities. We use PYTHIA and Delphes to simulate an analysis of the angular distribution of gg → X → γγ decays in a full 2012 data set, including realistic background levels. We show that this angular distribution should provide strong discrimination between the possibilities of spin zero and spin two with graviton-like couplings: ∝3 σ if a conservative symmetric interpretation of the log-likelihood ratio (LLR) test statistic is used, and ∝6 σ if a less conservative asymmetric interpretation is used. The WW and ZZ couplings of the Standard Model Higgs boson and of a 2 + particle with graviton-like couplings are both expected to exhibit custodial symmetry. We simulate the present ATLAS and CMS search strategies for X → WW * using PYTHIA and Delphes, and show that their efficiencies in the case of a spin-2 particle with graviton-like couplings are a factor ≅ 1.9 smaller than in the spin-0 case. On the other hand, the ratio of X 2 + → WW * and ZZ * branching ratios is larger than that in the 0 + case by a factor ≅ 1.3. We find that the current ATLAS and CMS results for X → WW * and X → ZZ * decays are compatible with custodial symmetry under both the spin-0 and -2 hypotheses, and that the data expected to become available during 2012 are unlikely to discriminate significantly between these possibilities. (orig.)

High rate of complete responses to immune checkpoint inhibitors in patients with relapsed or refractory Hodgkin lymphoma previously exposed to epigenetic therapy

Directory of Open Access Journals (Sweden)

Lorenzo Falchi

2016-11-01

Full Text Available Abstract Options for patients with relapsed or refractory (R/R classical Hodgkin lymphoma (cHL after brentuximab vedotin (Bv and autologous stem cell transplantation (ASCT are limited. Immune checkpoint inhibitors (ICI are active in this population but rarely induce complete response (CR. Ten patients with R/R cHL after ASCT and Bv received pembrolizumab (n = 8 or nivolumab (n = 2. Five had been previously exposed to 5-azacitidine on a phase 1 study. Among nine evaluable patients, seven (78% achieved CR, one partial response, and one reduction of tumor burden. All five patients who had received 5-azacitidine prior to ICI achieved CR, while only two of four who did not receive prior 5-azacitidine achieved CR. At a median follow-up of 9.9 months [0.5–14.3], eight patients are alive and five are still receiving treatment. We documented an unprecedented CR rate after ICI in patients with R/R cHL. We hypothesize that hypomethylating agents might have an immune priming effect and enhance the efficacy of ICI.

An exploration into the home field, global advantage and liability of unfamiliarness hypotheses in multinational banking

Directory of Open Access Journals (Sweden)

Fadzlan Sufian

2011-09-01

Full Text Available This paper seeks to expand the efficiency paradigm of the eclectic theory in multinational banking within the context of a developing country banking sector. We employ the Data Envelopment Analysis (DEA method to examine the efficiency of multinational banks operating in the Malaysian banking sector from 1995 to 2007. We then employ the panel regression analysis to examine the impact of origins on bank efficiency. We find foreign banks from North America to be the most efficient banking group, providing support to the ‘limited form’ of the global advantage hypothesis. On the other hand, we do not find evidence on both the liability of unfamiliarness and home field advantage hypotheses.

Are characiform fishes Gondwanan in origin? Insights from a time-scaled molecular phylogeny of the Citharinoidei (Ostariophysi: Characiformes.

Directory of Open Access Journals (Sweden)

Jairo Arroyave

Full Text Available Fishes of the order Characiformes are a diverse and economically important teleost clade whose extant members are found exclusively in African and Neotropical freshwaters. Although their transatlantic distribution has been primarily attributed to the Early Cretaceous fragmentation of western Gondwana, vicariance has not been tested with temporal information beyond that contained in their fragmentary fossil record and a recent time-scaled phylogeny focused on the African family Alestidae. Because members of the suborder Citharinoidei constitute the sister lineage to the entire remaining Afro-Neotropical characiform radiation, we inferred a time-calibrated molecular phylogeny of citharinoids using a popular Bayesian approach to molecular dating in order to assess the adequacy of current vicariance hypotheses and shed light on the early biogeographic history of characiform fishes. Given that the only comprehensive phylogenetic treatment of the Citharinoidei has been a morphology-based analysis published over three decades ago, the present study also provided an opportunity to further investigate citharinoid relationships and update the evolutionary framework that has laid the foundations for the current classification of the group. The inferred chronogram is robust to changes in calibration priors and suggests that the origins of citharinoids date back to the Turonian (ca 90 Ma of the Late Cretaceous. Most modern citharinoid genera, however, appear to have originated and diversified much more recently, mainly during the Miocene. By reconciling molecular-clock- with fossil-based estimates for the origins of the Characiformes, our results provide further support for the hypothesis that attributes the disjunct distribution of the order to the opening of the South Atlantic Ocean. The striking overlap in tempo of diversification and biogeographic patterns between citharinoids and the African-endemic family Alestidae suggests that their evolutionary

Why Victory in the War on Cancer Remains Elusive: Biomedical Hypotheses and Mathematical Models

Directory of Open Access Journals (Sweden)

Leonid Hanin

2011-01-01

Full Text Available We discuss philosophical, methodological, and biomedical grounds for the traditional paradigm of cancer and some of its critical flaws. We also review some potentially fruitful approaches to understanding cancer and its treatment. This includes the new paradigm of cancer that was developed over the last 15 years by Michael Retsky, Michael Baum, Romano Demicheli, Isaac Gukas, William Hrushesky and their colleagues on the basis of earlier pioneering work of Bernard Fisher and Judah Folkman. Next, we highlight the unique and pivotal role of mathematical modeling in testing biomedical hypotheses about the natural history of cancer and the effects of its treatment, elaborate on model selection criteria, and mention some methodological pitfalls. Finally, we describe a specific mathematical model of cancer progression that supports all the main postulates of the new paradigm of cancer when applied to the natural history of a particular breast cancer patient and fit to the observables.

Diversification in continental island archipelagos: new evidence on the roles of fragmentation, colonization and gene flow on the genetic divergence of Aegean Nigella (Ranunculaceae).

Science.gov (United States)

Jaros, Ursula; Tribsch, Andreas; Comes, Hans Peter

2018-02-12

Disentangling the relative roles of past fragmentation (vicariance), colonization (dispersal) and post-divergence gene flow in the genetic divergence of continental island organisms remains a formidable challenge. Amplified fragment length polymorphisms (AFLPs) were used to (1) gain further insights into the biogeographical processes underlying the Pleistocene diversification of the Aegean Nigella arvensis complex; (2) evaluate the role of potential key factors driving patterns of population genetic variability (mating system, geographical isolation and historical contingencies); and (3) test the robustness of conclusions previously drawn from chloroplast (cp) DNA. Genetic diversity was analysed for 235 AFLP markers from 48 populations (497 individuals) representing 11 taxa of the complex using population genetic methods and Bayesian assignment tests. Most designated taxa are identifiable as genetically distinct units. Both fragmentation and dispersal-driven diversification processes occurred at different geological time scales, from Early to Late Pleistocene, specifically (1) sea barrier-induced vicariant speciation in the Cyclades, the Western Cretan Strait and Ikaria; and (2) bi-regional colonizations of the 'Southern Aegean Island Arc' from the Western vs. Eastern Aegean mainland, followed by allopatric divergences in Crete vs. Rhodos and Karpathos/Kasos. Outcrossing island taxa experienced drift-related demographic processes that are magnified in the two insular selfing species. Population genetic differentiation on the mainland seems largely driven by dispersal limitation, while in the Central Aegean it may still be influenced by historical events (island fragmentation and sporadic long-distance colonization). The biogeographical history of Aegean Nigella is more complex than expected for a strictly allopatric vicariant model of divergence. Nonetheless, the major phylogeographical boundaries of this radiation are largely congruent with the geography and

18 CFR 154.302 - Previously submitted material.

Science.gov (United States)

2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Previously submitted material. 154.302 Section 154.302 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY... concurrently with the rate change filing. There must be furnished to the Director, Office of Energy Market...

Subsequent pregnancy outcome after previous foetal death

NARCIS (Netherlands)

Nijkamp, J. W.; Korteweg, F. J.; Holm, J. P.; Timmer, A.; Erwich, J. J. H. M.; van Pampus, M. G.

Objective: A history of foetal death is a risk factor for complications and foetal death in subsequent pregnancies as most previous risk factors remain present and an underlying cause of death may recur. The purpose of this study was to evaluate subsequent pregnancy outcome after foetal death and to

Male/Female Preferences for Masculine-Feminine Trait Clusters Derived from a Multidimensional Scaling of Hypothesized Masculine-Feminine and Creative-Noncreative Trait Terms.

Science.gov (United States)

Hyman, Ruth Bernstein

There still remains in our social institutions and individual lives a considerable splitting between feminine and masculine gender distinctions. The present study determined the dimensionality of the space of 53 admirable personality traits hypothesized to relate to femininity-masculinity and creativity, and assessed preferences of females versus…

Left ventricular asynergy score as an indicator of previous myocardial infarction

International Nuclear Information System (INIS)

Backman, C.; Jacobsson, K.A.; Linderholm, H.; Osterman, G.

1986-01-01

Sixty-eight patients with coronary heart disease (CHD) i.e. a hisotry of angina of effort and/or previous 'possible infarction' were examined inter alia with ECG and cinecardioangiography. A system of scoring was designed which allowed a semiquantitative estimate of the left ventricular asynergy from cinecardioangiography - the left ventricular motion score (LVMS). The LVMS was associated with the presence of a previous myocardial infarction (MI), as indicated by the history and ECG findings. The ECG changes specific for a previous MI were associated with high LVMS values and unspecific or absent ECG changes with low LVMS values. Decision thresholds for ECG changes and asynergy in diagnosing a previous MI were evaluated by means of a ROC analysis. The accuracy of ECG in detecting a previous MI was slightly higher when asynergy indicated a 'true MI' than when autopsy result did so in a comparable group. Therefore the accuracy of asynergy (LVMS ≥ 1) in detecting a previous MI or myocardial fibrosis in patients with CHD should be at least comparable with that of autopsy (scar > 1 cm). (orig.)

Taxonomic and phytogeographic implications from ITS phylogeny in Berberis (Berberidaceae).

Science.gov (United States)

Kim, Young-Dong; Kim, Sung-Hee; Landrum, Leslie R

2004-06-01

A phylogeny based on the internal transcribed spacer (ITS) sequences from 79 taxa representing much of the diversity of Berberis L. (four major groups and 22 sections) was constructed for the first time. The phylogeny was basically congruent with the previous classification schemes at higher taxonomic levels, such as groups and subgroups. A notable exception is the non-monophyly of the group Occidentales of compound-leaved Berberis (previously separated as Mahonia). At lower levels, however, most of previous sections and subsections were not evident especially in simple-leaved Berberis. Possible relationship between section Horridae (group Occidentales) and the simple-leaved Berberis clade implies paraphyly of the compound-leaved Berberis. A well-known South America-Old World (mainly Asia) disjunctive distribution pattern of the simple-leaved Berberis is explained by a vicariance event occurring in the Cretaceous period. The ITS phylogeny also suggests that a possible connection between the Asian and South American groups through the North American species ( Berberis canadensis or B. fendleri) is highly unlikely.

Reasoning with Previous Decisions: Beyond the Doctrine of Precedent

DEFF Research Database (Denmark)

Komárek, Jan

2013-01-01

in different jurisdictions use previous judicial decisions in their argument, we need to move beyond the concept of precedent to a wider notion, which would embrace practices and theories in legal systems outside the Common law tradition. This article presents the concept of ‘reasoning with previous decisions...... law method’, but they are no less rational and intellectually sophisticated. The reason for the rather conceited attitude of some comparatists is in the dominance of the common law paradigm of precedent and the accompanying ‘case law method’. If we want to understand how courts and lawyers......’ as such an alternative and develops its basic models. The article first points out several shortcomings inherent in limiting the inquiry into reasoning with previous decisions by the common law paradigm (1). On the basis of numerous examples provided in section (1), I will present two basic models of reasoning...

On the Tengiz petroleum deposit previous study

International Nuclear Information System (INIS)

Nysangaliev, A.N.; Kuspangaliev, T.K.

1997-01-01

Tengiz petroleum deposit previous study is described. Some consideration about structure of productive formation, specific characteristic properties of petroleum-bearing collectors are presented. Recommendation on their detail study and using of experience on exploration and development of petroleum deposit which have analogy on most important geological and industrial parameters are given. (author)

What Will Dental Practice Be Like In 2025? Will You Help Dental Hypotheses Find Answers

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Edward F. Rossomando

2011-02-01

Full Text Available As a result of the rapid acceptance of digital dental equipment, the dental office of 2011 looks very different from that of 1900. Despite these changes, the general dentist of 2011 performs almost the same functions as in 1900 namely the restoration of decayed teeth and the replacement of those lost due to disease. In addition to changes in technology, the last few decades of the 20th century ushered in a revolution in biology leading to the development of a genomic basis of dental disease and the development of bio-based diagnostics and therapeutics. In 2011 few if any of these bio-discoveries have changed dental practice but by 2025 we expect they will. In this editorial, Dental Hypotheses asks readers to “hypothesize” on what dental practice will be like in 2025.

Diversification in a biodiversity hotspot--the evolution of Southeast Asian rhacophorid tree frogs on Borneo (Amphibia: Anura: Rhacophoridae).

Science.gov (United States)

Hertwig, Stefan T; Schweizer, Manuel; Das, Indraneil; Haas, Alexander

2013-09-01

The tree-frog family Rhacophoridae is a major group contributing to the high pecies richness and reproductive diversity among vertebrates of Sundaland. Nonetheless, rhacophorid evolution, specially on Borneo, has not been studied within a phylogenetic context. In this study, we examine the phylogenetic relationships of 38 (out of 41) Bornean species of Rhacophoridae, in combination with data from previous phylogenetic studies. In the final super matrix of 91 species, we analyse sequence data from two mitochondrial and three nuclear genes. The resulting trees show the genus Rhacophorus as a paraphyletic assemblage. As a consequence, we transfer Rhacophorus appendiculatus and R. kajau to two other genera and propose the new phylogeny-based combinations--Kurixalus appendiculatus and Feihyla kajau, respectively. Furthermore, we use our phylogenetic hypotheses to reconstruct the evolution of reproductive modes in rhacophorid tree frogs. Direct development to the exclusion of a free larval stage evolved twice independently, once in an ancestor of the Pseudophilautus+Raorchestes clade in India and Sri Lanka, and once within Philautus in Southeast Asia. The deposition of egg clutches covered by a layer of jelly in Feihyla is also present in F. kajau and thus confirms our generic reassignment. The remarkably high diversity of rhacophorid tree frogs on Borneo is the outcome of a complex pattern of repeated vicariance and dispersal events caused by past changes in the climatic and geological history of the Sunda shelf. We identified geographic clades of closely related endemic species within Rhacophorus and Philautus, which result from local island radiations on Borneo. Copyright © 2013 Elsevier Inc. All rights reserved.

Exaptation in human evolution: how to test adaptive vs exaptive evolutionary hypotheses.

Science.gov (United States)

Pievani, Telmo; Serrelli, Emanuele

2011-01-01

Palaeontologists, Stephen J. Gould and Elisabeth Vrba, introduced the term "ex-aptation" with the aim of improving and enlarging the scientific language available to researchers studying the evolution of any useful character, instead of calling it an "adaptation" by default, coming up with what Gould named an "extended taxonomy of fitness". With the extension to functional co-optations from non-adaptive structures ("spandrels"), the notion of exaptation expanded and revised the neo-Darwinian concept of "pre-adaptation" (which was misleading, for Gould and Vrba, suggesting foreordination). Exaptation is neither a "saltationist" nor an "anti-Darwinian" concept and, since 1982, has been adopted by many researchers in evolutionary and molecular biology, and particularly in human evolution. Exaptation has also been contested. Objections include the "non-operationality objection".We analyze the possible operationalization of this concept in two recent studies, and identify six directions of empirical research, which are necessary to test "adaptive vs. exaptive" evolutionary hypotheses. We then comment on a comprehensive survey of literature (available online), and on the basis of this we make a quantitative and qualitative evaluation of the adoption of the term among scientists who study human evolution. We discuss the epistemic conditions that may have influenced the adoption and appropriate use of exaptation, and comment on the benefits of an "extended taxonomy of fitness" in present and future studies concerning human evolution.

A DNA and morphology based phylogenetic framework of the ant genus Lasius with hypotheses for the evolution of social parasitism and fungiculture

Directory of Open Access Journals (Sweden)

Stauffer Christian

2008-08-01

Full Text Available Abstract Background Ants of the genus Lasius are ecologically important and an important system for evolutionary research. Progress in evolutionary research has been hindered by the lack of a well-founded phylogeny of the subgenera, with three previous attempts disagreeing. Here we employed two mitochondrial genes (cytochrome c oxidase subunit I, 16S ribosomal RNA, comprising 1,265 bp, together with 64 morphological characters, to recover the phylogeny of Lasius by Bayesian and Maximum Parsimony inference after exploration of potential causes of phylogenetic distortion. We use the resulting framework to infer evolutionary pathways for social parasitism and fungiculture. Results We recovered two well supported major lineages. One includes Acanthomyops, Austrolasius, Chthonolasius, and Lasius pallitarsis, which we confirm to represent a seventh subgenus, the other clade contains Dendrolasius, and Lasius sensu stricto. The subgenus Cautolasius, displaying neither social parasitism nor fungiculture, probably belongs to the second clade, but its phylogenetic position is not resolved at the cutoff values of node support we apply. Possible causes for previous problems with reconstructing the Lasius phylogeny include use of other reconstruction techniques, possibly more prone to instabilities in some instances, and the inclusion of phylogenetically distorting characters. Conclusion By establishing an updated phylogenetic framework, our study provides the basis for a later formal taxonomic revision of subgenera and for studying the evolution of various ecologically and sociobiologically relevant traits of Lasius, although there is need for future studies to include nuclear genes and additional samples from the Nearctic. Both social parasitism and fungiculture evolved twice in Lasius, once in each major lineage, which opens up new opportunities for comparative analyses. The repeated evolution of social parasitism has been established for other groups of

Should previous mammograms be digitised in the transition to digital mammography?

International Nuclear Information System (INIS)

Taylor-Phillips, S.; Gale, A.G.; Wallis, M.G.

2009-01-01

Breast screening specificity is improved if previous mammograms are available, which presents a challenge when converting to digital mammography. Two display options were investigated: mounting previous film mammograms on a multiviewer adjacent to the workstation, or digitising them for soft copy display. Eight qualified screen readers were videotaped undertaking routine screen reading for two 45-min sessions in each scenario. Analysis of gross eye and head movements showed that when digitised, previous mammograms were examined a greater number of times per case (p=0.03), due to a combination of being used in 19% more cases (p=0.04) and where used, looked at a greater number of times (28% increase, p=0.04). Digitising previous mammograms reduced both the average time taken per case by 18% (p=0.04) and the participants' perceptions of workload (p < 0.05). Digitising previous analogue mammograms may be advantageous, in particular in increasing their level of use. (orig.)

14 CFR 121.406 - Credit for previous CRM/DRM training.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Credit for previous CRM/DRM training. 121... previous CRM/DRM training. (a) For flightcrew members, the Administrator may credit CRM training received before March 19, 1998 toward all or part of the initial ground CRM training required by § 121.419. (b...