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Sample records for surface inflection hypothesis

  1. Theory for computing the field scattered from a smooth inflected surface

    Science.gov (United States)

    Barger, R. L.; Dominek, A. K.

    1986-01-01

    A theory is described for computing the reflected or scattered field from a smooth body with inflection points. These inflections occur in certain directions at each surface point for which the total (Gaussian) curvature is zero or negative. For surface illumination in one of these critical directions, the usual reflection formulas obtained by the high-frequency approximation are inapplicable, and a shadow zone exists in the reflected field. Scattering into the shadow zone is treated, as well as specular reflection. This theory should have a variety of applications such as for certain optics problems, computer graphics modeling of three-dimensional shapes, and the design and analysis of specialized microwave reflector antennas.

  2. Reflections on inflections

    Science.gov (United States)

    Saengow, C.; Giacomin, A. J.; Gilbert, P. H.; Kolitawong, C.

    2015-11-01

    In plastics processing, the single most important rheological property is the steady shear viscosity curve: the logarithm of the steady shear viscosity versus the logarithm of the shear rate. This curve governs the volumetric flowrate through any straight channel flow, and thus governs the production rate of extruded plastics. If the shear rate is made dimensionless with a characteristic time for the fluid (called the Weissenberg number, Wi), then we can readily identify the end of the Newtonian plateau of a viscosity curve with the value Wi≈1. Of far greater importance, however, is the slope at the point where the viscosity curve inflects, ( n-1), where n is called the shear power-law index. This paper explores the physics of this point and related inflections, in the first and second normal stress coefficients. We also discuss the first and second inflection pairing times, λ'B and λ″B. First, we examine the generalized Newtonian fluid (Carreau model). Then, we analyze the more versatile model, the corotational Oldroyd 8-constant model, which reduces to many simpler models, for instance, the corotational Maxwell and Jeffreys models. We also include worked examples to illustrate the procedure for calculating inflection points and power-law coefficients for all three viscometric functions, η ( {dot γ } ), {Ψ _1}( {dot γ } ) and {Ψ _2}( {dot γ } ).

  3. ASSESSING THE SO CALLED MARKED INFLECTIONAL FEATURES OF NIGERIAN ENGLISH: A SECOND LANGUAGE ACQUISITION THEORY ACCOUNT

    OpenAIRE

    Boluwaji Oshodi

    2014-01-01

    There are conflicting claims among scholars on whether the structural outputs of the types of English spoken in countries where English is used as a second language gives such speech forms the status of varieties of English. This study examined those morphological features considered to be marked features of the variety spoken in Nigeria according to Kirkpatrick (2011) and the variety spoken in Malaysia by considering the claims of the Missing Surface Inflection Hypothesis (MSIH) a Second Lan...

  4. Inflectional frames in language production

    NARCIS (Netherlands)

    Janssen, D.P.; Roelofs, A.P.A.; Levelt, W.J.M.

    2002-01-01

    The authors report six implicit priming experiments that examined the production of inflected forms. Participants produced words out of small sets in response to prompts. The words differed in form or shared word-initial segments, which allowed for preparation. In constant inflectional sets, the

  5. ASSESSING THE SO CALLED MARKED INFLECTIONAL FEATURES OF NIGERIAN ENGLISH: A SECOND LANGUAGE ACQUISITION THEORY ACCOUNT

    Directory of Open Access Journals (Sweden)

    Boluwaji Oshodi

    2014-04-01

    Full Text Available There are conflicting claims among scholars on whether the structural outputs of the types of English spoken in countries where English is used as a second language gives such speech forms the status of varieties of English. This study examined those morphological features considered to be marked features of the variety spoken in Nigeria according to Kirkpatrick (2011 and the variety spoken in Malaysia by considering the claims of the Missing Surface Inflection Hypothesis (MSIH a Second Language Acquisition theory which accounts for the cause of the variable use of such inflections among L2 learners. Results from oral and written composition tasks administered on selected undergraduate students of Nigerian and Malaysian universities revealed that what is regarded as morphological features are actually a deviation from the L2 target forms. According to the MSIH the variability in the use of such inflections is due to problems of lexical retrieval a psycholinguistic problem which manifests among L2 learners of English generally which results in wrong surface representations.

  6. Pluto and Charon: Surface Colors and Compositions - A Hypothesis

    Science.gov (United States)

    Cruikshank, D. P.

    2016-01-01

    The surface of Pluto displays an array of colors ranging from yellow to red to brown, while the surface of Charon is largely gray with a north polar zone of red color similar to regions on Pluto. Pluto's surface shows layers of intensely colored material in tilted and transported blocks, and fractured geo-graphical units. This arrangement suggests episodes of formation or deposition of that material interspersed with episodes of emplacement of ices having little or no color. The ices identified on the surfaces of these two bodies (N2, CH4, CO, C2H6, H2O on Pluto, and H2O and NH3 on Charon) are colorless, as are nearly all ices in a powdery state. The colors on Pluto probably arise from the in situ formation of a macro-molecular carbonaceous material generated by energetic processing of the ices on the surface. Laboratory experiments producing refractory tholins particularly relevant to Pluto explored the chemistry of both UV and low-energy electron bombardment of a mix of Pluto ices (N2:CH4:CO = 100:1:1). We can term this Pluto ice tholin PIT. Water ice in the crystalline state characterizes Charon's surface, and while most of Charon's surface is neutral in color, with geometric albedo approximately 0.38, the polar zone and a light cover of fainter but similar reddish color over some surface regions suggest a common origin with the colored material on Pluto. NH3 or NH3 x nH2O was identified from disk-integrated Earth-based spectra, and a few concentrated NH3 exposures have been found in the New Horizons spectral images.

  7. Reproduction of inflectional markers in French-speaking children with reading impairment.

    Science.gov (United States)

    St-Pierre, Marie-Catherine; Béland, Renée

    2010-04-01

    Children with reading impairment (RI) experience difficulties in oral and written production of inflectional markers. The origin of these difficulties is not well documented in French. According to some authors, acquisition of irregular items by typically developing children is predicted by token frequency, whereas acquisition of regular items is predicted by type frequency. The authors hypothesized that acquisition of inflectional markers in French depends on the distribution of irregular, invariable, and regular (transparent) items within a grammatical category. Fifteen children with RI age matched with 15 children with typical reading development repeated and read aloud sentences containing adjectives inflected for gender and verbs inflected for number. Inflected adjectives and verbs were matched for token frequency and phonological complexity, whereas distribution of invariable, transparent, and irregular items differed within each grammatical category. Results show higher error rates in the RI group, who produced more errors in reading than repetition, and more errors on inflected verbs than adjectives. Error distribution varied with the proportion of invariable, irregular, and transparent items within each grammatical category, confirming the authors' hypothesis. The authors concluded that morphological difficulties of children with RI group originated from a delay in extracting systematicity in verb and adjective inflectional marking.

  8. A model of language inflection graphs

    Science.gov (United States)

    Fukś, Henryk; Farzad, Babak; Cao, Yi

    2014-01-01

    Inflection graphs are highly complex networks representing relationships between inflectional forms of words in human languages. For so-called synthetic languages, such as Latin or Polish, they have particularly interesting structure due to the abundance of inflectional forms. We construct the simplest form of inflection graphs, namely a bipartite graph in which one group of vertices corresponds to dictionary headwords and the other group to inflected forms encountered in a given text. We, then, study projection of this graph on the set of headwords. The projection decomposes into a large number of connected components, to be called word groups. Distribution of sizes of word group exhibits some remarkable properties, resembling cluster distribution in a lattice percolation near the critical point. We propose a simple model which produces graphs of this type, reproducing the desired component distribution and other topological features.

  9. Whole-word frequency and inflectional paradigm size facilitate Estonian case-inflected noun processing.

    Science.gov (United States)

    Lõo, Kaidi; Järvikivi, Juhani; Baayen, R Harald

    2018-06-01

    Estonian is a morphologically rich Finno-Ugric language with nominal paradigms that have at least 28 different inflected forms but sometimes more than 40. For languages with rich inflection, it has been argued that whole-word frequency, as a diagnostic of whole-word representations, should not be predictive for lexical processing. We report a lexical decision experiment, showing that response latencies decrease both with frequency of the inflected form and its inflectional paradigm size. Inflectional paradigm size was also predictive of semantic categorization, indicating it is a semantic effect, similar to the morphological family size effect. These findings fit well with the evidence for frequency effects of word n-grams in languages with little inflectional morphology, such as English. Apparently, the amount of information on word use in the mental lexicon is substantially larger than was previously thought. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Inflection point inflation and time dependent potentials in string theory

    International Nuclear Information System (INIS)

    Itzhaki, Nissan; Kovetz, Ely D.

    2007-01-01

    We consider models of inflection point inflation. The main drawback of such models is that they suffer from the overshoot problem. Namely the initial condition should be fine tuned to be near the inflection point for the universe to inflate. We show that stringy realizations of inflection point inflation are common and offer a natural resolution to the overshoot problem

  11. Influence of Productivity on the Acquisition of Inflectional Markers

    DEFF Research Database (Denmark)

    Kjærbæk, Laila; Basbøll, Hans; Christensen, René dePont

    Influence of productivity on the acquisition of inflectional markers Studies on acquisition of inflectional morphology often distinguish between ‘regular’ and ‘irregular’ inflection. This distinction originates from studies of English, which is characterized by having one default inflectional...... marker for a grammatical category (e.g. the PL suffix -s) and a minor number of exceptions to this default rule. We find this distinction rather inexpedient since this is not the case for all languages (e.g. Danish, German). In order to address this issue we have developed a scale with three degrees...

  12. Mastering Inflectional Suffixes: A Longitudinal Study of Beginning Writers' Spellings

    Science.gov (United States)

    Turnbull, Kathryn; Deacon, S. Helene; Bird, Elizabeth Kay-Raining

    2011-01-01

    This study tracked the order in which ten beginning spellers (M age = 5 ; 05; SD = 0.21 years) mastered the correct spellings of common inflectional suffixes in English. Spellings from children's journals from kindergarten and grade 1 were coded. An inflectional suffix was judged to be mastered when children spelled it accurately in 90 percent of…

  13. Inflectional morphology in primary progressive aphasia: an elicited production study.

    Science.gov (United States)

    Wilson, Stephen M; Brandt, Temre H; Henry, Maya L; Babiak, Miranda; Ogar, Jennifer M; Salli, Chelsey; Wilson, Lisa; Peralta, Karen; Miller, Bruce L; Gorno-Tempini, Maria Luisa

    2014-09-01

    Inflectional morphology lies at the intersection of phonology, syntax and the lexicon, three language domains that are differentially impacted in the three main variants of primary progressive aphasia (PPA). To characterize spared and impaired aspects of inflectional morphology in PPA, we elicited inflectional morphemes in 48 individuals with PPA and 13 healthy age-matched controls. We varied the factors of regularity, frequency, word class, and lexicality, and used voxel-based morphometry to identify brain regions where atrophy was predictive of deficits on particular conditions. All three PPA variants showed deficits in inflectional morphology, with the specific nature of the deficits dependent on the anatomical and linguistic features of each variant. Deficits in inflecting low-frequency irregular words were associated with semantic PPA, with lexical/semantic deficits, and with left temporal atrophy. Deficits in inflecting pseudowords were associated with non-fluent/agrammatic and logopenic variants, with phonological deficits, and with left frontal and parietal atrophy. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Testing the dark matter hypothesis with low surface brightness galaxies and other evidence

    NARCIS (Netherlands)

    McGaugh, SS; de Blok, WJG

    1998-01-01

    The severity of the mass discrepancy in spiral galaxies is strongly correlated with the central surface brightness of their disks. Progressively lower surface brightness galaxies have ever larger mass discrepancies. No other parameter (luminosity, size, velocity, morphology) is so well correlated

  15. Case inflection of construct state constructions in Dinka

    DEFF Research Database (Denmark)

    Andersen, Torben

    2016-01-01

    Dinka, a Nilo-Saharan language, is largely monosyllabic, but nevertheless it has a fairly rich morphology. Thus, most of its morphology is expressed by alternations in phonological material of the root. The inflectional categories of nouns manifested in this way include state and case in addition...... to number. The state category consists of an absolute state and two construct states. The case category includes a nominative, a genitive, an allative, and an essive/ablative. The present article shows how case inflection is manifested in complex noun phrases consisting of a noun in a construct state...... simultaneously carry state information and case information. Thus, the case inflection of construct state constructions in Dinka adds yet another layer of nonlinear morphology to nouns in this language....

  16. Efficient Encoding of Inflection Rules in NLP Systems

    Directory of Open Access Journals (Sweden)

    Péter BARABÁSS

    2012-12-01

    Full Text Available The grammatical parsing unit is a core module in natural language processing engines. This unit determines the grammatical roles of the incoming words and it converts the sentences into semantic models. A special grammar rule in agglutinative languages is the inflection rule. The traditional, automata-based parsers are usually not very effective in the parsing of inflection transformations. The paper presents implementation alternatives and compares them from the viewpoint of time efficiency and accuracy. The prototype system was tested with examples from Hungarian.

  17. Surface ECG interatrial block-guided treatment for stroke prevention: rationale for an attractive hypothesis.

    Science.gov (United States)

    Bayés de Luna, Antoni; Martínez-Sellés, Manuel; Bayés-Genís, Antoni; Elosua, Roberto; Baranchuk, Adrian

    2017-07-31

    Atrial fibrillation (AF) is the most common sustained arrhythmia and is associated with stroke, cognitive impairment, and cardiovascular death. Some predisposing factors - as aging, diabetes, hypertension - induce and maintain electrophysiological and ultrastructural remodeling that usually includes fibrosis. Interatrial conduction disturbances play a crucial role in the initiation of atrial fibrosis and in its associated complications. The diagnosis of interatrial blocks (IABs) is easy to perform using the surface ECG. IAB is classified as partial when the P wave duration is ≥120 ms, and advanced if the P wave also presents a biphasic pattern in II, III and aVF. IAB is very frequent in the elderly and, particularly in the case of the advanced type, is associated with AF, AF recurrences, stroke, and dementia. The anticoagulation in elderly patients at high risk of AF without documented arrhythmias is an open issue but recent data suggest that it might have a role, particularly in elderly patients with structural heart disease, high CHA 2 DS 2 VASc (Congestive heart failure/left ventricular dysfunction, Hypertension, Age ≥ 75 [doubled], Diabetes, Stroke [doubled] - Vascular disease, Age 65-74, and Sex category [female]), and advanced IAB. In this debate, we discuss the association of surface ECG IAB, a marker of atrial fibrosis, with AF and stroke. We also present the rationale that justifies further studies regarding anticoagulation in some of these patients.

  18. L2 Processing of Plural Inflection in English

    Science.gov (United States)

    Song, Yoonsang

    2015-01-01

    This study investigates (1) whether late second language (L2) learners can attain native-like knowledge of English plural inflection even when their first language (L1) lacks an equivalent and (2) whether they construct hierarchically structured representations during online sentence processing like native speakers. In a self-paced reading task,…

  19. Effects of age on the acquisition of agreement inflection

    NARCIS (Netherlands)

    Blom, E.; Polišenská, D.; Weerman, F.

    2007-01-01

    Grammaticality judgement tasks show that second language learners who started during childhood are significantly more accurate on judging inflection than learners who started after puberty [Johnson, J., & Newport, E. (1989). Cognitive Psychology, 21, 60-99; Johnson, J., & Newport, E. (1991).

  20. Rhetorical Scarcity: Spatial and Economic Inflections on Genre Change

    Science.gov (United States)

    Applegarth, Risa

    2012-01-01

    This study examines how changes in a key scientific genre supported anthropology's early twentieth-century bid for scientific status. Combining spatial theories of genre with inflections from the register of economics, I develop the concept of "rhetorical scarcity" to characterize this genre change not as evolution but as manipulation that…

  1. On primordial black holes from an inflection point

    NARCIS (Netherlands)

    Germani, Cristiano; Prokopec, Tom

    2017-01-01

    Recently, it has been claimed that inflationary models with an inflection point in the scalar potential can produce a large resonance in the power spectrum of curvature perturbation. In this paper however we show that the previous analyses are incorrect. The reason is twofold: firstly, the inflaton

  2. Case inflection of construct state constructions in Dinka

    DEFF Research Database (Denmark)

    Andersen, Torben

    2016-01-01

    and a following modifier. It is demonstrated that the case inflection of such noun phrases is manifested almost exclusively by tonal overlays on the nominative (lexical) tones, and that such overlays may occur either in the head or in the modifier or in both the head and the modifier. In this way, a head noun may...

  3. A Comparison of Two Theoretically Driven Treatments for Verb Inflection Deficits in Aphasia

    Science.gov (United States)

    Faroqi-Shah, Yasmeen

    2008-01-01

    Errors in the production of verb inflections, especially tense inflections, are pervasive in agrammatic Broca's aphasia ("*The boy eat"). The neurolinguistic underpinnings of these errors are debated. One group of theories attributes verb inflection errors to disruptions in encoding the verb's morphophonological form, resulting from either a…

  4. Inflectional Morphology in Cri du Chat Syndrome--A Case Study

    Science.gov (United States)

    Kristoffersen, Kristian Emil

    2012-01-01

    This study examined morphological skills in a girl with cri du chat syndrome, addressing three questions: (1) To what extent does the subject inflect words? (2) To what extent are words inflected correctly? (3) To what extent do the inflected words reflect productive morphological rules, and to what extent can they be considered to be…

  5. The hypothesis of formation of the structure of surfaced metal at the surfacing based on the application of the prognostic algorithm of control the electrode wire speed

    Directory of Open Access Journals (Sweden)

    Lebedev V. A.

    2017-12-01

    Full Text Available The growth of a drop in the process of surfacing by a consumable electrode is characterized by a linear dependence of the current change on time. A hypothesis has been put forward, according to which a reduction in the feed rate of the electrode wire to zero in this time interval will substantially reduce the spraying loss and improve the formation of the surfacing roller. For the implementation of which, the use of regulators with a typical law of regulation is proposed, but not according to the current value of the arc current, but according to the forecast. A key feature of these researches is a realization given surfacing process with the imposition of external mechanical oscillations with specified amplitude-frequency characteristics on the welding bath. Analytical calculation of the transfer function for the prognostic PID regulator with the simplest linear prediction taking into account the oscillation of the weld pool is given.

  6. Predictive value of ventilatory inflection points determined under field conditions.

    Science.gov (United States)

    Heyde, Christian; Mahler, Hubert; Roecker, Kai; Gollhofer, Albert

    2016-01-01

    The aim of this study was to evaluate the predictive potential provided by two ventilatory inflection points (VIP1 and VIP2) examined in field without using gas analysis systems and uncomfortable facemasks. A calibrated respiratory inductance plethysmograph (RIP) and a computerised routine were utilised, respectively, to derive ventilation and to detect VIP1 and VIP2 during a standardised field ramp test on a 400 m running track on 81 participants. In addition, average running speed of a competitive 1000 m run (S1k) was observed as criterion. The predictive value of running speed at VIP1 (SVIP1) and the speed range between VIP1 and VIP2 in relation to VIP2 (VIPSPAN) was analysed via regression analysis. VIPSPAN rather than running speed at VIP2 (SVIP2) was operationalised as a predictor to consider the covariance between SVIP1 and SVIP2. SVIP1 and VIPSPAN, respectively, provided 58.9% and 22.9% of explained variance in regard to S1k. Considering covariance, the timing of two ventilatory inflection points provides predictive value in regard to a competitive 1000 m run. This is the first study to apply computerised detection of ventilatory inflection points in a field setting independent on measurements of the respiratory gas exchange and without using any facemasks.

  7. Managing Inflections in Life and Career: Tale from a Physicist

    Science.gov (United States)

    Bhattacharya, Santanu

    2010-03-01

    By training, a physicist possesses one of the rarest qualities ever imparted in an educational degree program, namely, the ability to take on complex problems, divide them into ``solvable'' parts, derive solutions and put them back as insightful outputs. Dr Bhattacharya, CEO of Salorix, a research, analytics and consulting firm, explains how he has used these skills learned at the graduate school to build a career as a scientist, management consultant and entrepreneur. He will also speak about how the real-life skillsets of understanding and dealing with ``Inflections'', self discovery and introspection can be a great tool for managing one's life and career progression.

  8. Principle for possible memory structures with extra high density by using the electron sharing mechanisms of atoms in an inflective orbit

    Science.gov (United States)

    Sengor, T.

    2014-10-01

    Both of the qualitative and quantitative knowledge of electromagnetic fields in the inter-atomic scale bring useful applications. From this point of view, bringing some possible new sights and solutions to atom-electron-photon-atom and/or molecule interactions is aimed in the near-field at inter atomic scale and their potential applications. The electron sharing processes between neighbor atoms are considered as an inflective surface system and an inflective guiding processes. The critical pass and transition structures are derived. The structures involving trigging that transition mechanisms may be suitable to design extra high density and fast data storage processes. The electron sharing processes between two near atomic system are modelled with gate mechanisms involving two distinct passages: continuous pass and discontinuous pass. Even if the stochastic processes are applicable at these cases theoretical approach putting an influence like inner and external dipole mechanisms fits best to the situation and provides almost deterministic scheme, which has potential to estimate some processes being able to design new electronics structures and devices. We call orbitron all of such structures and/or devices. The boundary value problem of atomic system sharing an electron in the way of electron passage model is formulated in inflective spherical coordinate system. The wave phenomenon is studied near spherically inflection points. The analytical essentials are derived for the solution of Helmholtz's equation when inflective boundaries are included. The evaluation is obtained by the extracted separation method. The results are given by using the spherically inflective wave series. The method is reshaped for the solution of Schrödinger equation.

  9. Verb inflection in monolingual Dutch and sequential bilingual Turkish-Dutch children with and without SLI

    NARCIS (Netherlands)

    Blom, E.; de Jong, J.; Orgassa, A.; Baker, A.; Weerman, F.

    2013-01-01

    Both children with specific language impairment (SLI) and children who acquire a second language (L2) make errors with verb inflection. This overlap between SLI and L2 raises the question if verb inflection can discriminate between L2 children with and without SLI. In this study we addressed this

  10. Apoptosis at inflection point in liquid culture of budding yeasts.

    Directory of Open Access Journals (Sweden)

    Toshiyuki Hagiwara

    Full Text Available Budding yeasts are highly suitable for aging studies, because the number of bud scars (stage proportionally correlates with age. Its maximum stages are known to reach at 20-30 stages on an isolated agar medium. However, their stage dynamics in a liquid culture is virtually unknown. We investigate the population dynamics by counting scars in each cell. Here one cell division produces one new cell and one bud scar. This simple rule leads to a conservation law: "The total number of bud scars is equal to the total number of cells." We find a large discrepancy: extremely fewer cells with over 5 scars than expected. Almost all cells with 6 or more scars disappear within a short period of time in the late log phase (corresponds to the inflection point. This discrepancy is confirmed directly by the microscopic observations of broken cells. This finding implies apoptosis in older cells (6 scars or more.

  11. A Global comparison of surface soil characteristics across five cities: A test of the urban ecosystem convergence hypothesis.

    Science.gov (United States)

    Richard V. Pouyat; Ian D. Yesilonis; Miklos Dombos; Katalin Szlavecz; Heikki Setala; Sarel Cilliers; Erzsebet Hornung; D. Johan Kotze; Stephanie. Yarwood

    2015-01-01

    As part of the Global Urban Soil Ecology and Education Network and to test the urban ecosystem convergence hypothesis, we report on soil pH, organic carbon (OC), total nitrogen (TN), phosphorus (P), and potassium (K) measured in four soil habitat types (turfgrass, ruderal, remnant, and reference) in five metropolitan areas (Baltimore, Budapest,...

  12. Verbal inflection, articles and object clitics in Italian specific language impairment.

    Science.gov (United States)

    Junyent, Andrea Anahí; Levorato, Maria Chiara; Denes, Gianfranco

    2010-11-01

    Morphosyntactic skills in spontaneous and elicited production of a 7-year-old boy with specific language impairment (SLI) were examined and compared to those of younger, mean length of utterance (MLU)-matched, typically-developing children. This study focused on inflectional phrase structures as well as complex constructions in order to investigate hypotheses which suggest verbal inflection is a key deficit underlying SLI. It analysed the most affected morphemes in Italian: articles and direct and indirect object clitics. A deficit was found in verbal inflection as well as in articles and object clitics. The difficulties with verbal inflection found were expected given the child's MLU. Problems with articles and clitics were unexpected for MLU, presenting a challenge for hypotheses that focus on verbal inflection.

  13. Children with specific language impairment in Finnish: the use of tense and agreement inflections.

    Science.gov (United States)

    Kunnari, Sari; Savinainen-Makkonen, Tuula; Leonard, Laurence B; Mäkinen, Leena; Tolonen, Anna-Kaisa; Luotonen, Mirja; Leinonen, Eeva

    2011-11-01

    Children with specific language impairment (SLI) vary widely in their ability to use tense/agreement inflections depending on the type of language being acquired, a fact that current accounts of SLI have tried to explain. Finnish provides an important test case for these accounts because: (1) verbs in the first and second person permit null subjects whereas verbs in the third person do not; and (2) tense and agreement inflections are agglutinating and thus one type of inflection can appear without the other. Probes were used to compare the verb inflection use of Finnish-speaking children with SLI, and both age-matched and younger typically developing children. The children with SLI were less accurate, and the pattern of their errors did not match predictions based on current accounts of SLI. It appears that children with SLI have difficulty learning complex verb inflection paradigms apart from any problem specific to tense and agreement.

  14. Comparing Different Models of the Development of Verb Inflection in Early Child Spanish

    Science.gov (United States)

    Aguado-Orea, Javier; Pine, Julian M.

    2015-01-01

    How children acquire knowledge of verb inflection is a long-standing question in language acquisition research. In the present study, we test the predictions of some current constructivist and generativist accounts of the development of verb inflection by focusing on data from two Spanish-speaking children between the ages of 2;0 and 2;6. The constructivist claim that children’s early knowledge of verb inflection is only partially productive is tested by comparing the average number of different inflections per verb in matched samples of child and adult speech. The generativist claim that children’s early use of verb inflection is essentially error-free is tested by investigating the rate at which the children made subject-verb agreement errors in different parts of the present tense paradigm. Our results show: 1) that, although even adults’ use of verb inflection in Spanish tends to look somewhat lexically restricted, both children’s use of verb inflection was significantly less flexible than that of their caregivers, and 2) that, although the rate at which the two children produced subject-verb agreement errors in their speech was very low, this overall error rate hid a consistent pattern of error in which error rates were substantially higher in low frequency than in high frequency contexts, and substantially higher for low frequency than for high frequency verbs. These results undermine the claim that children’s use of verb inflection is fully productive from the earliest observable stages, and are consistent with the constructivist claim that knowledge of verb inflection develops only gradually. PMID:25760035

  15. Comparing different models of the development of verb inflection in early child Spanish.

    Science.gov (United States)

    Aguado-Orea, Javier; Pine, Julian M

    2015-01-01

    How children acquire knowledge of verb inflection is a long-standing question in language acquisition research. In the present study, we test the predictions of some current constructivist and generativist accounts of the development of verb inflection by focusing on data from two Spanish-speaking children between the ages of 2;0 and 2;6. The constructivist claim that children's early knowledge of verb inflection is only partially productive is tested by comparing the average number of different inflections per verb in matched samples of child and adult speech. The generativist claim that children's early use of verb inflection is essentially error-free is tested by investigating the rate at which the children made subject-verb agreement errors in different parts of the present tense paradigm. Our results show: 1) that, although even adults' use of verb inflection in Spanish tends to look somewhat lexically restricted, both children's use of verb inflection was significantly less flexible than that of their caregivers, and 2) that, although the rate at which the two children produced subject-verb agreement errors in their speech was very low, this overall error rate hid a consistent pattern of error in which error rates were substantially higher in low frequency than in high frequency contexts, and substantially higher for low frequency than for high frequency verbs. These results undermine the claim that children's use of verb inflection is fully productive from the earliest observable stages, and are consistent with the constructivist claim that knowledge of verb inflection develops only gradually.

  16. The processing of English regular inflections: Phonological cues to morphological structure

    Science.gov (United States)

    Post, Brechtje; Marslen-Wilson, William D.; Randall, Billi; Tyler, Lorraine K.

    2008-01-01

    Previous studies suggest that different neural and functional mechanisms are involved in the analysis of irregular (caught) and regular (filled) past tense forms in English. In particular, the comprehension and production of regular forms is argued to require processes of morpho-phonological assembly and disassembly, analysing these forms into a stem plus an inflectional affix (e.g., {fill} + {-ed}), as opposed to irregular forms, which do not have an overt stem + affix structure and must be analysed as full forms [Marslen-Wilson, W. D., & Tyler, L. K. (1997). Dissociating types of mental computation. Nature, 387, 592–594; Marslen-Wilson, W. D., & Tyler, L. K. (1998). Rules, representations, and the English past tense. Trends in Cognitive Science, 2, 428–435]. On this account, any incoming string that shows the critical diagnostic properties of an inflected form – a final coronal consonant (/t/, /d/, /s/, /z/) that agrees in voicing with the preceding segment as in filled, mild, or nilled – will automatically trigger an attempt at segmentation. We report an auditory speeded judgment experiment which explored the contribution of these critical morpho-phonological properties (labelled as the English inflectional rhyme pattern) to the processing of English regular inflections. The results show that any stimulus that can be interpreted as ending in a regular inflection, whether it is a real inflection (filled–fill), a pseudo-inflection (mild–mile) or a phonologically matched nonword (nilled–nill), is responded to more slowly than an unambiguously monomorphemic stimulus pair (e.g., belt–bell). This morpho-phonological effect was independent of phonological effects of voicing and syllabicity. The findings are interpreted as evidence for a basic morpho-phonological parsing process that applies to all items with the criterial phonological properties. PMID:18834584

  17. Life Origination Hydrate Hypothesis (LOH-Hypothesis).

    Science.gov (United States)

    Ostrovskii, Victor; Kadyshevich, Elena

    2012-01-04

    The paper develops the Life Origination Hydrate Hypothesis (LOH-hypothesis), according to which living-matter simplest elements (LMSEs, which are N-bases, riboses, nucleosides, nucleotides), DNA- and RNA-like molecules, amino-acids, and proto-cells repeatedly originated on the basis of thermodynamically controlled, natural, and inevitable processes governed by universal physical and chemical laws from CH4, niters, and phosphates under the Earth's surface or seabed within the crystal cavities of the honeycomb methane-hydrate structure at low temperatures; the chemical processes passed slowly through all successive chemical steps in the direction that is determined by a gradual decrease in the Gibbs free energy of reacting systems. The hypothesis formulation method is based on the thermodynamic directedness of natural movement and consists ofan attempt to mentally backtrack on the progression of nature and thus reveal principal milestones alongits route. The changes in Gibbs free energy are estimated for different steps of the living-matter origination process; special attention is paid to the processes of proto-cell formation. Just the occurrence of the gas-hydrate periodic honeycomb matrix filled with LMSEs almost completely in its final state accounts for size limitation in the DNA functional groups and the nonrandom location of N-bases in the DNA chains. The slowness of the low-temperature chemical transformations and their "thermodynamic front" guide the gross process of living matter origination and its successive steps. It is shown that the hypothesis is thermodynamically justified and testable and that many observed natural phenomena count in its favor.

  18. Life Origination Hydrate Hypothesis (LOH-Hypothesis

    Directory of Open Access Journals (Sweden)

    Victor Ostrovskii

    2012-01-01

    Full Text Available The paper develops the Life Origination Hydrate Hypothesis (LOH-hypothesis, according to which living-matter simplest elements (LMSEs, which are N-bases, riboses, nucleosides, nucleotides, DNA- and RNA-like molecules, amino-acids, and proto-cells repeatedly originated on the basis of thermodynamically controlled, natural, and inevitable processes governed by universal physical and chemical laws from CH4, niters, and phosphates under the Earth's surface or seabed within the crystal cavities of the honeycomb methane-hydrate structure at low temperatures; the chemical processes passed slowly through all successive chemical steps in the direction that is determined by a gradual decrease in the Gibbs free energy of reacting systems. The hypothesis formulation method is based on the thermodynamic directedness of natural movement and consists ofan attempt to mentally backtrack on the progression of nature and thus reveal principal milestones alongits route. The changes in Gibbs free energy are estimated for different steps of the living-matter origination process; special attention is paid to the processes of proto-cell formation. Just the occurrence of the gas-hydrate periodic honeycomb matrix filled with LMSEs almost completely in its final state accounts for size limitation in the DNA functional groups and the nonrandom location of N-bases in the DNA chains. The slowness of the low-temperature chemical transformations and their “thermodynamic front” guide the gross process of living matter origination and its successive steps. It is shown that the hypothesis is thermodynamically justified and testable and that many observed natural phenomena count in its favor.

  19. Near Infrared Multispectral Mapping of Venus Supports the Hypothesis that Tessera Plateau Material was Formed in the Presence of Surface Water

    Science.gov (United States)

    Mueller, N. T.; Tsang, C.; Nunes, D. C.; Helbert, J.; Dyar, M. D.; Smrekar, S. E.

    2017-12-01

    The VIRTIS instrument on Venus Express observed surface thermal emission from the surface. Studies of 1020nm data showed that tessera plateaus, intensely tectonically deformed highlands that predate most other terrains, have significantly lower thermal emission than other highlands. Lower thermal emission could be due either to lower surface emissivity, supporting the hypothesis that tessera are analogous to continental crust on Earth, or to a bias of Magellan altimetry, which does not fully resolve the topographic relief of tessera terrain. To eliminate this ambiguity, we additionally investigate the spectral windows at 1100 and 1180nm. Data are reduced to surface emissivity using an atmospheric radiative transfer model to account for atmospheric scattering and absorption/emission. Magellan altimetry was used to model atmospheric column height and surface temperature. The model uses a binary (collision-induced) absorption coefficient for each window. It fits absolute radiance and gradient with surface elevation reasonably well, although there are indications that the assumed adiabatic temperature lapse rate is not appropriate globally. The 1100nm band has a relatively low signal-to-noise ratio at the latitudes of the tessera plateaus, but Alpha Regio is visible in both the 1020 and the 1180nm band. The difference in emissivity between Alpha and the adjacent corona Eve, which has a similar elevation as Alpha, is 3.6% at 1020nm, but only 2% at 1180nm. The altimetry bias equivalent to the 1020nm deviation is 230 m, while the equivalent is only 70m at 1180nm. An altimetry bias therefore cannot fully explain the observations, and there must be a real difference in emissivity. The observations are consistent with the hypothesis that Alpha Regio has a more felsic composition. The emissivity spectra of granites at Venus temperatures are lower than those of basalt at 1020nm, but the difference decreases or vanishes towards the 1180nm window. The most plausible explanation

  20. Tidal volume inflection and its sensory consequences during exercise in patients with stable asthma.

    Science.gov (United States)

    Laveneziana, Pierantonio; Bruni, Giulia Innocenti; Presi, Ilenia; Stendardi, Loredana; Duranti, Roberto; Scano, Giorgio

    2013-01-15

    Sixteen patients with stable asthma performed a symptom-limited constant work-rate CWR cycle exercise during which breathing pattern, operating lung volumes, dyspnea intensity and its qualitative descriptors were measured. An inflection in the relation between tidal volume (V(T)) and ventilation (V˙(E)) was observed in each subject. The sense of "work/effort" was the dominant dyspnea descriptor selected up to the V(T)/V˙(E) inflection, whereas after it dyspnea intensity and the selection frequency of "unsatisfied inspiration" rose steeply in 37.5% of subjects in whom inspiratory reserve volume (IRV) had decreased to a critical level of 0.6L at the V(T) inflection point. In contrast, dyspnea increased linearly with exercise time and V˙(E), and "work/effort" was the dominant descriptor selected throughout exercise in 62.5% of subjects in whom the V(T)/V˙(E) inflection occurred at a preserved IRV. The V(T) inflection during exercise in patients with stable asthma marked a mechanical event with important sensory consequences only when it occurred at a critical reduced IRV. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Gene expression profiling supports the hypothesis that human ovarian surface epithelia are multipotent and capable of serving as ovarian cancer initiating cells

    Directory of Open Access Journals (Sweden)

    Matyunina Lilya V

    2009-12-01

    Full Text Available Abstract Background Accumulating evidence suggests that somatic stem cells undergo mutagenic transformation into cancer initiating cells. The serous subtype of ovarian adenocarcinoma in humans has been hypothesized to arise from at least two possible classes of progenitor cells: the ovarian surface epithelia (OSE and/or an as yet undefined class of progenitor cells residing in the distal end of the fallopian tube. Methods Comparative gene expression profiling analyses were carried out on OSE removed from the surface of normal human ovaries and ovarian cancer epithelial cells (CEPI isolated by laser capture micro-dissection (LCM from human serous papillary ovarian adenocarcinomas. The results of the gene expression analyses were randomly confirmed in paraffin embedded tissues from ovarian adenocarcinoma of serous subtype and non-neoplastic ovarian tissues using immunohistochemistry. Differentially expressed genes were analyzed using gene ontology, molecular pathway, and gene set enrichment analysis algorithms. Results Consistent with multipotent capacity, genes in pathways previously associated with adult stem cell maintenance are highly expressed in ovarian surface epithelia and are not expressed or expressed at very low levels in serous ovarian adenocarcinoma. Among the over 2000 genes that are significantly differentially expressed, a number of pathways and novel pathway interactions are identified that may contribute to ovarian adenocarcinoma development. Conclusions Our results are consistent with the hypothesis that human ovarian surface epithelia are multipotent and capable of serving as the origin of ovarian adenocarcinoma. While our findings do not rule out the possibility that ovarian cancers may also arise from other sources, they are inconsistent with claims that ovarian surface epithelia cannot serve as the origin of ovarian cancer initiating cells.

  2. Early words, multiword utterances and maternal reading strategies as predictors of mastering word inflections in Finnish.

    Science.gov (United States)

    Silvén, Maarit; Ahtola, Annarilla; Niemi, Pekka

    2003-05-01

    This is the first study to report how children's language skills and mothers' book-reading strategies, measured at 2;0, predict mastery of word inflections at 3;0 and 5;0 in a sample of 66 Finnish children. Three theoretical models were tested on the longitudinal data using path analyses. The testing of the models suggests direct developmental continuity from producing words and multiword utterances on later inflectional growth, but indirect effects of maternal strategies on language outcomes. Moreover, mothers' complex expansions and questions are positively related, whereas labellings and corrections are negatively related, to children's concurrent and subsequent language skills. Finally, vocabulary size relates negatively to maternal attention regulation. When joint attention is easily built up in the dyad, mothers concentrate more on direct reading, which, together with the child's vocabulary, predicts mastery of inflections. In conclusion, the results can be viewed as support for a child-driven view on the future course of language acquisition.

  3. The production of nominal and verbal inflection in an agglutinative language: evidence from Hungarian.

    Science.gov (United States)

    Nemeth, Dezso; Janacsek, Karolina; Turi, Zsolt; Lukacs, Agnes; Peckham, Don; Szanka, Szilvia; Gazso, Dorottya; Lovassy, Noemi; Ullman, Michael T

    2015-01-01

    The contrast between regular and irregular inflectional morphology has been useful in investigating the functional and neural architecture of language. However, most studies have examined the regular/irregular distinction in non-agglutinative Indo-European languages (primarily English) with relatively simple morphology. Additionally, the majority of research has focused on verbal rather than nominal inflectional morphology. The present study attempts to address these gaps by introducing both plural and past tense production tasks in Hungarian, an agglutinative non-Indo-European language with complex morphology. Here we report results on these tasks from healthy Hungarian native-speaking adults, in whom we examine regular and irregular nominal and verbal inflection in a within-subjects design. Regular and irregular nouns and verbs were stem on frequency, word length, and phonological structure, and both accuracy and response times were acquired. The results revealed that the regular/irregular contrast yields similar patterns in Hungarian, for both nominal and verbal inflection, as in previous studies of non-agglutinative Indo-European languages: the production of irregular inflected forms was both less accurate and slower than of regular forms, both for plural and past-tense inflection. The results replicate and extend previous findings to an agglutinative language with complex morphology. Together with previous studies, the evidence suggests that the regular/irregular distinction yields a basic behavioral pattern that holds across language families and linguistic typologies. Finally, the study sets the stage for further research examining the neurocognitive substrates of regular and irregular morphology in an agglutinative non-Indo-European language.

  4. Orienting India : interwar internationalism in an Asian inflection, 1917-1937

    NARCIS (Netherlands)

    Stolte, Carolina Margaretha

    2013-01-01

    ‘Orienting India: Interwar Internationalism in an Asian Inflection, 1917-1937’ is an intellectual history of (Pan-) Asianist individuals, initiatives and movements in South Asia in the years between the two world wars. The First World War, the Bolshevik Revolution and the establishment of the League

  5. Spelling of Derivational and Inflectional Suffixes by Greek-Speaking Children with and without Dyslexia

    Science.gov (United States)

    Diamanti, Vassiliki; Goulandris, Nata; Stuart, Morag; Campbell, Ruth

    2014-01-01

    We investigated the spelling of derivational and inflectional suffixes by 10-13-year-old Greek children. Twenty children with dyslexia (DYS), 20 spelling-level-matched (SA) and 20 age-matched (CA) children spelled adjectives, nouns, and verbs in dictated word pairs and sentences. Children spelled nouns and verbs more accurately than adjectives and…

  6. On the Distinction between Regular and Irregular Inflectional Morphology: Evidence from Dinka

    Science.gov (United States)

    Ladd, D. Robert; Remijsen, Bert; Manyang, Caguor Adong

    2009-01-01

    Discussions of the psycholinguistic significance of regularity in inflectional morphology generally deal with languages in which regular forms can be clearly identified and revolve around whether there are distinct processing mechanisms for regular and irregular forms. We present a detailed description of Dinka's notoriously irregular noun number…

  7. Fossilization in Steady State L2 Grammars: Persistent Problems with Inflectional Morphology.

    Science.gov (United States)

    White, Lydia

    2003-01-01

    Provides a case study of the fossilized endstate of the second language (L2) English grammar of an adult native speaker of Turkish. Results are presented from production data, concentrating on verbal and nominal inflection and associated syntactic properties. (Author/VWL)

  8. Reproduction of Inflectional Markers in French-Speaking Children with Reading Impairment

    Science.gov (United States)

    St-Pierre, Marie-Catherine; Beland, Renee

    2010-01-01

    Purpose: Children with reading impairment (RI) experience difficulties in oral and written production of inflectional markers. The origin of these difficulties is not well documented in French. According to some authors, acquisition of irregular items by typically developing children is predicted by token frequency, whereas acquisition of regular…

  9. Third-Person Present Singular Verb Inflection in Early British and American English.

    Science.gov (United States)

    Kyto, Merja

    1993-01-01

    In a sociohistorical variation analysis of verb inflection in Early Modern British and American English, corpus-based comparisons focus on several extralinguistic and linguistic factors that have influenced the choice of forms over successive periods of time. Contrary to customary theories of "colonial lag," the rate of change was faster…

  10. An Inflection Point Method for the Determination of Pulmonary Transit Time From Contrast Echocardiography.

    Science.gov (United States)

    Boronyak, Steven M; Monahan, Ken; Brittain, Evan L; Merryman, W David

    2015-07-01

    Indicator-dilution curves (IDCs) for the estimation of pulmonary transit times (PTTs) can be generated noninvasively using contrast echocardiography. Currently, these IDCs are analyzed by manual inspection, which is not feasible in a clinical setting, or fit to a statistical model to derive parameters of interest. However, IDCs generated from patients are frequently subject to significant low-frequency noise and recirculation artifacts that obscure the first-pass signal and render model fitting impractical or inaccurate. Thus, the objective of this paper was to develop alternative computational methods to determine PTT using noisy clinical data in which the signal decay is not adequately visible. We report on a method that uses a model fit to the rise portion of the IDCs to determine the signal inflection point. Additionally, a signal truncation algorithm was developed that enables automated analysis of the IDCs. We compare PTTs derived from our inflection point method to those obtained by manual inspection in 25 patients (R(2) = 0.86) and to those obtained by mean transit time calculation following fitting to a local density random walk model (R(2) = 0.80) in a subset of this cohort. Combined with a signal truncation algorithm, the inflection point method provides robust, automated determination of PTT from noisy IDCs containing recirculation artifacts. The inflection point method addresses the need for computational analysis of IDCs obtained from contrast echocardiograms that are not amenable to first-pass model fitting.

  11. Two-Year-Olds' Sensitivity to Inflectional Plural Morphology: Allomorphic Effects

    Science.gov (United States)

    Davies, Benjamin; Xu Rattanasone, Nan; Demuth, Katherine

    2017-01-01

    Many English-speaking children use plural nominal forms in spontaneous speech before the age of two, and display some understanding of plural inflection in production tasks. However, results from an intermodal preferential study suggested a lack of "comprehension" of nominal plural morphology at 24 months of age (Kouider, Halberda, Wood,…

  12. An Elicited-Production Study of Inflectional Verb Morphology in Child Finnish

    Science.gov (United States)

    Räsänen, Sanna H. M.; Ambridge, Ben; Pine, Julian M.

    2016-01-01

    Many generativist accounts (e.g., Wexler, 1998) argue for very early knowledge of inflection on the basis of very low rates of person/number marking errors in young children's speech. However, studies of Spanish (Aguado-Orea & Pine, 2015) and Brazilian Portuguese (Rubino & Pine, 1998) have revealed that these low overall error rates…

  13. On the relation between verb inflection and verb position in Dutch agrammatic aphasics

    NARCIS (Netherlands)

    Bastiaanse, Y.R.M.; van Zonneveld, R.M.

    This study focuses on the relation between verb position and verb inflection in the speech production of Dutch agrammatic patients. In Dutch, the finite verb is moved to second position in the matrix clause (de jongen leest een boek: the boy reads a book), but remains in its base generated, that is

  14. Passive margin high altitude low relief surfaces: old or new? Testing the glacial/periglacial buzzsaw hypothesis on the landscape of Southern Norway.

    Science.gov (United States)

    Berthling, Ivar

    2015-04-01

    Low relief surfaces at relatively high altitude are a main characteristic of the landscape in Southern Norway. These surfaces have for more than a century been regarded as old surfaces, originally developed as low altitude peneplains and later tectonically uplifted during the Cenozoic (e.g. LidmarBergstrom et al., 2000). Recently, this standard model has been challenged by models suggesting more recent uplift from erosionally driven isostatic adjustments during Pliocene and Pleistocene (Nielsen et al., 2009) or also earlier (Gołędowski et al., 2013). These models differ in opinion as to how and when the surfaces actually have developed from denudational processes in increasingly colder climates, unconstrained by a common base level, but both a glacial and a periglacial 'buzzsaw' have been invoked. If this interpretation is correct, it provides an example of large-scale periglacial bedrock landscape development and further underlines the importance of cryo-conditioning for long-term landscape development (Berthling and Etzelmüller, 2011) and the interconnected role of earth surface processes in cold climates. According to (French, 2007), however, large scale periglacial landscapes are rare or non-existent. Testing the periglacial 'buzzsaw' is therefore important, both for addressing the potential general long-term effects of periglacial processes on landscape development, and specifically to evaluate the mentioned models for Cenozoic landscape development. Here, we assess both the standard model and the glacial/periglacial 'buzzsaw' hypotheses on the Southern Norway landscape development, based on available field relationships. The periglacial 'buzzsaw' involves two aspects: sediment production by frost weathering, and sediment transport by periglacial mass wasting, i.e. solifluction and/or permafrost creep. Several studies evaluate frost weathering at the landscape scale, but periglacial mass wasting - especially regarding solifluction - has mainly been

  15. Wavelength scanning distance interferometry using inflection point retrieval for phase unwrapping

    Science.gov (United States)

    Ma, Rende; Li, Xiaoping; Dong, Xinyong; Xia, Yunjie

    2018-03-01

    A real-time wavelength scanning distance interferometry is proposed. The interference signal generated by the light wavelength modulation is transformed into preliminary conversion signal with the two summarized waveform transformation laws. Inflection points of the interference signal are retrieved with two complementary methods which are discontinuity point judgment (DPJ) and the adjacent null points distance judgment (ANPDJ). Based on the preliminary conversion signal and the retrieved inflection points, the orthogonal signal is constructed. Displacement is calculated after demodulating the phase shift with the orthogonal demodulation algorithm. When millimeters distance is measured, the fluctuation of the measured result is around micrometers in about one hour. The measurement complexity and cost are all decreased, while, ideal measurement results can still be obtained. The approach can be used in a multitude of applications.

  16. Exponentiated Weibull distribution approach based inflection S-shaped software reliability growth model

    Directory of Open Access Journals (Sweden)

    B.B. Sagar

    2016-09-01

    Full Text Available The aim of this paper was to estimate the number of defects in software and remove them successfully. This paper incorporates Weibull distribution approach along with inflection S-shaped Software Reliability Growth Models (SRGM. In this combination two parameter Weibull distribution methodology is used. Relative Prediction Error (RPE is calculated to predict the validity criterion of the developed model. Experimental results on actual data from five data sets are compared with two other existing models, which expose that the proposed software reliability growth model predicts better estimation to remove the defects. This paper presents best software reliability growth model with including feature of both Weibull distribution and inflection S-shaped SRGM to estimate the defects of software system, and provide help to researchers and software industries to develop highly reliable software products.

  17. The effect of phonological realization of inflectional morphology on verbal agreement in French

    Science.gov (United States)

    Frenck-Mestre, Cheryl; Osterhout, Lee; McLaughlin, Judy; Foucart, Alice

    2008-01-01

    The present study examined the impact of the phonological realization of morphosyntactic agreement within the inflectional phrase (IP) in written French, as revealed by ERPs. In two independent experiments, we varied the presence vs. absence of phonological cues to morphological variation. Of interest was whether a graded ERP response to these different conditions could be found in native speakers (Experiment 1), and whether non-native learners would benefit from the presence of phonological cues (Experiment 2). The results for native French speakers showed that compared to grammatically correct instances, phonologically realized inflectional errors produced a significant P600 response, which was statistically larger than that produced by errors that were silent. German L1 French L2 learners showed similar benefits of the phonological realization of morphemes. Phonologically realized errors produced a robust P600 response whereas silent errors produced no robust effects. Implications of these results are discussed in reference to previous studies of L2 acquisition of morphosyntax. PMID:18255043

  18. Development of early morphological awareness in Greek: Epilinguistic versus metalinguistic and inflectional versus derivational awareness

    OpenAIRE

    Diamanti, Vassiliki; Benaki, Argyro; Mouzaki, Angeliki; Ralli, Asimina; Antoniou, Faye; Papaioannou, Sophia; Protopapas, Athanassios

    2017-01-01

    This cross-sectional study examined the development of morphological awareness in Greek children 4–7 years old. A distinction was adopted between epilinguistic control, evidenced in judgment tasks and indicative of elementary levels of awareness, and metalinguistic awareness, evidenced in production tasks and indicative of full-blown conscious awareness. The morphological domains of inflectional and derivational morphology were specifically contrasted to determine whether they follow distinct...

  19. Inflectional and derivational morphological spelling abilities of children with Specific Language Impairment

    Directory of Open Access Journals (Sweden)

    Sarah eCritten

    2014-08-01

    Full Text Available Children with Specific Language Impairment (SLI are known to have difficulties with spelling but the factors which underpin these difficulties, are a matter of debate. The present study investigated the impact of oral language and literacy on the bound morpheme spelling abilities of children with SLI. Thirty-three children with SLI (9-10 years and two control groups, one matched for chronological age (CA and one for language and spelling age (LA (aged 6-8 years were given dictated spelling tasks of 24 words containing inflectional morphemes and 18 words containing derivational morphemes. There were no significant differences between the SLI group and their LA matches in accuracy or error patterns for inflectional morphemes. By contrast when spelling derivational morphemes the SLI group was less accurate and made proportionately more omissions and phonologically implausible errors than both control groups. Spelling accuracy was associated with phonological awareness and reading; reading performance significantly predicted the ability to spell both inflectional and derivational morphemes. The particular difficulties experienced by the children with SLI for derivational morphemes are considered in relation to reading and oral language.

  20. Dissociating neural subsystems for grammar by contrasting word order and inflection.

    Science.gov (United States)

    Newman, Aaron J; Supalla, Ted; Hauser, Peter; Newport, Elissa L; Bavelier, Daphne

    2010-04-20

    An important question in understanding language processing is whether there are distinct neural mechanisms for processing specific types of grammatical structure, such as syntax versus morphology, and, if so, what the basis of the specialization might be. However, this question is difficult to study: A given language typically conveys its grammatical information in one way (e.g., English marks "who did what to whom" using word order, and German uses inflectional morphology). American Sign Language permits either device, enabling a direct within-language comparison. During functional (f)MRI, native signers viewed sentences that used only word order and sentences that included inflectional morphology. The two sentence types activated an overlapping network of brain regions, but with differential patterns. Word order sentences activated left-lateralized areas involved in working memory and lexical access, including the dorsolateral prefrontal cortex, the inferior frontal gyrus, the inferior parietal lobe, and the middle temporal gyrus. In contrast, inflectional morphology sentences activated areas involved in building and analyzing combinatorial structure, including bilateral inferior frontal and anterior temporal regions as well as the basal ganglia and medial temporal/limbic areas. These findings suggest that for a given linguistic function, neural recruitment may depend upon on the cognitive resources required to process specific types of linguistic cues.

  1. Inflectional and derivational morphological spelling abilities of children with Specific Language Impairment

    Science.gov (United States)

    Critten, Sarah; Connelly, Vincent; Dockrell, Julie E.; Walter, Kirsty

    2014-01-01

    Children with Specific Language Impairment (SLI) are known to have difficulties with spelling but the factors that underpin these difficulties, are a matter of debate. The present study investigated the impact of oral language and literacy on the bound morpheme spelling abilities of children with SLI. Thirty-three children with SLI (9–10 years) and two control groups, one matched for chronological age (CA) and one for language and spelling age (LA) (aged 6–8 years) were given dictated spelling tasks of 24 words containing inflectional morphemes and 18 words containing derivational morphemes. There were no significant differences between the SLI group and their LA matches in accuracy or error patterns for inflectional morphemes. By contrast when spelling derivational morphemes the SLI group was less accurate and made proportionately more omissions and phonologically implausible errors than both control groups. Spelling accuracy was associated with phonological awareness and reading; reading performance significantly predicted the ability to spell both inflectional and derivational morphemes. The particular difficulties experienced by the children with SLI for derivational morphemes are considered in relation to reading and oral language. PMID:25221533

  2. Electrophysiological evidence for the continuous processing of linguistic categories of regular and irregular verb inflection in German.

    Science.gov (United States)

    Smolka, Eva; Khader, Patrick H; Wiese, Richard; Zwitserlood, Pienie; Rösler, Frank

    2013-08-01

    A central question concerning word recognition is whether linguistic categories are processed in continuous or categorical ways, in particular, whether regular and irregular inflection is stored and processed by the same or by distinct systems. Here, we contribute to this issue by contrasting regular (regular stem, regular suffix) with semi-irregular (regular stem, irregular suffix) and irregular (irregular stem, irregular suffix) participle formation in a visual priming experiment on German verb inflection. We measured ERPs and RTs and manipulated the inflectional and meaning relatedness between primes and targets. Inflected verb targets (e.g., leite, "head") were preceded either by themselves, by their participle (geleitet, "headed"), by a semantically related verb in the same inflection as the target (führe, "guide") or in the participle form (geführt, "guided"), or by an unrelated verb in the same inflection (nenne, "name"). Results showed that behavioral and ERP priming effects were gradually affected by verb regularity. Regular participles produced a widely distributed frontal and parietal effect, irregular participles produced a small left parietal effect, and semi-irregular participles yielded an effect in-between these two in terms of amplitude and topography. The behavioral and ERP effects further showed that the priming because of participles differs from that because of semantic associates for all verb types. These findings argue for a single processing system that generates participle priming effects for regular, semi-irregular, and irregular verb inflection. Together, the findings provide evidence that the linguistic categories of verb inflection are processed continuously. We present a single-system model that can adequately account for such graded effects.

  3. Physiopathological Hypothesis of Cellulite

    OpenAIRE

    de Godoy, Jos? Maria Pereira; de Godoy, Maria de F?tima Guerreiro

    2009-01-01

    A series of questions are asked concerning this condition including as regards to its name, the consensus about the histopathological findings, physiological hypothesis and treatment of the disease. We established a hypothesis for cellulite and confirmed that the clinical response is compatible with this hypothesis. Hence this novel approach brings a modern physiological concept with physiopathologic basis and clinical proof of the hypothesis. We emphasize that the choice of patient, correct ...

  4. Variability: A Pernicious Hypothesis.

    Science.gov (United States)

    Noddings, Nel

    1992-01-01

    The hypothesis of greater male variability in test results is discussed in its historical context, and reasons feminists have objected to the hypothesis are considered. The hypothesis acquires political importance if it is considered that variability results from biological, rather than cultural, differences. (SLD)

  5. Modeling of PV Systems Based on Inflection Points Technique Considering Reverse Mode

    Directory of Open Access Journals (Sweden)

    Bonie J. Restrepo-Cuestas

    2013-11-01

    Full Text Available This paper proposes a methodology for photovoltaic (PV systems modeling, considering their behavior in both direct and reverse operating mode and considering mismatching conditions. The proposed methodology is based on the inflection points technique with a linear approximation to model the bypass diode and a simplified PV model. The proposed mathematical model allows to evaluate the energetic performance of a PV system, exhibiting short simulation times in large PV systems. In addition, this methodology allows to estimate the condition of the modules affected by the partial shading since it is possible to know the power dissipated due to its operation at the second quadrant.

  6. Surface Tension of Supercooled Water: No Inflection Point down to-25 degrees C

    Czech Academy of Sciences Publication Activity Database

    Hrubý, Jan; Vinš, Václav; Mareš, R.; Hykl, Jiří; Kalová, J.

    2014-01-01

    Roč. 5, č. 3 (2014), s. 425-428 ISSN 1948-7185 R&D Projects: GA AV ČR(CZ) IAA200760905; GA ČR(CZ) GPP101/11/P046; GA MŠk(CZ) LG13056 Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100761201 Institutional support: RVO:61388998 Keywords : liquid * metastable * supercooled Subject RIV: JE - Non-nuclear Energetics, Energy Consumption ; Use Impact factor: 7.458, year: 2014

  7. Discrete Frenet frame, inflection point solitons, and curve visualization with applications to folded proteins

    Science.gov (United States)

    Hu, Shuangwei; Lundgren, Martin; Niemi, Antti J.

    2011-06-01

    We develop a transfer matrix formalism to visualize the framing of discrete piecewise linear curves in three-dimensional space. Our approach is based on the concept of an intrinsically discrete curve. This enables us to more effectively describe curves that in the limit where the length of line segments vanishes approach fractal structures in lieu of continuous curves. We verify that in the case of differentiable curves the continuum limit of our discrete equation reproduces the generalized Frenet equation. In particular, we draw attention to the conceptual similarity between inflection points where the curvature vanishes and topologically stable solitons. As an application we consider folded proteins, their Hausdorff dimension is known to be fractal. We explain how to employ the orientation of Cβ carbons of amino acids along a protein backbone to introduce a preferred framing along the backbone. By analyzing the experimentally resolved fold geometries in the Protein Data Bank we observe that this Cβ framing relates intimately to the discrete Frenet framing. We also explain how inflection points (a.k.a. soliton centers) can be located in the loops and clarify their distinctive rôle in determining the loop structure of folded proteins.

  8. Physiopathological Hypothesis of Cellulite

    Science.gov (United States)

    de Godoy, José Maria Pereira; de Godoy, Maria de Fátima Guerreiro

    2009-01-01

    A series of questions are asked concerning this condition including as regards to its name, the consensus about the histopathological findings, physiological hypothesis and treatment of the disease. We established a hypothesis for cellulite and confirmed that the clinical response is compatible with this hypothesis. Hence this novel approach brings a modern physiological concept with physiopathologic basis and clinical proof of the hypothesis. We emphasize that the choice of patient, correct diagnosis of cellulite and the technique employed are fundamental to success. PMID:19756187

  9. Derivation of equations to define inflection point and its analysis in flattening filter free photon beams based on the principle of polynomial function

    Directory of Open Access Journals (Sweden)

    KR Muralidhar

    2015-03-01

    Full Text Available Purpose: The objective of this work is to (1 present a mechanism for calculating inflection points on profiles at various depths and field sizes, and (2 study the doses at the inflection points for various field sizes at depth of maximum dose (Dmax for flattening filter free (FFF photon beam profiles. Methods: Graphical representation was done on percentage of dose versus inflection points. Also, using the polynomial function, the author formulated equations for calculating spot-on inflection point on the profiles for both the 6MV and 10 MV energies for different field sizes at various depths. Results: In a 10 MV FFF radiation beam, the dose at inflection point of the profile decreases as the field size increases. However, in 6MV FFF radiation beam, the dose at the inflection point initially increases with an increase in the field size up to 10 ×10 cm2 and decreases after 10 ×10 cm2. The polynomial function was fitted for both the 6 MV and 10 MV FFF beams for all field sizes and depths. Conclusion: Polynomial function is one of the easiest ways of identifying the inflection point in FFF beam for various field sizes and depths. Graphical representation of dose versus inflection point for both FFF energies was derived.

  10. AN ERP STUDY OF REGULAR AND IRREGULAR ENGLISH PAST TENSE INFLECTION

    Science.gov (United States)

    Newman, Aaron J.; Ullman, Michael T.; Pancheva, Roumyana; Waligura, Diane L.; Neville, Helen J.

    2006-01-01

    Compositionality is a critical and universal characteristic of human language. It is found at numerous levels, including the combination of morphemes into words and of words into phrases and sentences. These compositional patterns can generally be characterized by rules. For example, the past tense of most English verbs (“regulars”) is formed by adding an -ed suffix. However, many complex linguistic forms have rather idiosyncratic mappings. For example, “irregular” English verbs have past tense forms that cannot be derived from their stems in a consistent manner. Whether regular and irregular forms depend on fundamentally distinct neurocognitive processes (rule-governed combination vs. lexical memorization), or whether a single processing system is sufficient to explain the phenomena, has engendered considerable investigation and debate. We recorded event-related potentials while participants read English sentences that were either correct or had violations of regular past tense inflection, irregular past tense inflection, syntactic phrase structure, or lexical semantics. Violations of regular past tense and phrase structure, but not of irregular past tense or lexical semantics, elicited left-lateralized anterior negativities (LANs). These seem to reflect neurocognitive substrates that underlie compositional processes across linguistic domains, including morphology and syntax. Regular, irregular, and phrase structure violations all elicited later positivities that were maximal over right parietal sites (P600s), and which seem to index aspects of controlled syntactic processing of both phrase structure and morphosyntax. The results suggest distinct neurocognitive substrates for processing regular and irregular past tense forms: regulars depending on compositional processing, and irregulars stored in lexical memory. PMID:17070703

  11. Precursors of Reading Skill from Infancy to First Grade in Finnish: Continuity and Change in a Highly Inflected Language

    Science.gov (United States)

    Silven, Maarit; Poskiparta, Elisa; Niemi, Pekka; Voeten, Marinus

    2007-01-01

    The course of language acquisition from infancy to public primary school was followed in a sample of 56 Finnish children to examine precursors to reading at first grade. Structural equation modeling of continuity suggested effects from growth in early vocabulary to mastery of inflectional forms at preschool age. The early language directly…

  12. Precursors of Reading Skill From Infancy to First Grade in Finnish: Continuity and Change in a Highly Inflected Language

    NARCIS (Netherlands)

    Silvén, M.; Poskiparta, E.H.; Niemi, P.; Voeten, M.J.M.

    2007-01-01

    The course of language acquisition from infancy to public primary school was followed in a sample of 56 Finnish children to examine precursors to reading at first grade. Structural equation modeling of continuity suggested effects from growth in early vocabulary to mastery of inflectional forms at

  13. Language and Preliteracy Skills in Bilinguals and Monolinguals at Preschool Age: Effects of Exposure to Richly Inflected Speech from Birth

    Science.gov (United States)

    Silven, Maarit; Rubinov, Evgenia

    2010-01-01

    Language proficiency before school entry has proven to be a powerful predictor of literacy development. This longitudinal study examined how simultaneous exposure to two richly inflected languages from birth contributes to the development of language-related literacy precursors at preschool age compared to peers exposed to one language. The…

  14. Verb inflection in German-learning children with typical and atypical language acquisition: the impact of subsyllabic frequencies.

    Science.gov (United States)

    Ott, Susan; Höhle, Barbara

    2013-01-01

    Previous research has shown that high phonotactic frequencies facilitate the production of regularly inflected verbs in English-learning children with specific language impairment (SLI) but not with typical development (TD). We asked whether this finding can be replicated for German, a language with a much more complex inflectional verb paradigm than English. Using an elicitation task, the production of inflected nonce verb forms (3(rd) person singular with -t suffix) with either high- or low-frequency subsyllables was tested in sixteen German-learning children with SLI (ages 4;1-5;1), sixteen TD-children matched for chronological age (CA) and fourteen TD-children matched for verbal age (VA) (ages 3;0-3;11). The findings revealed that children with SLI, but not CA- or VA-children, showed differential performance between the two types of verbs, producing more inflectional errors when the verb forms resulted in low-frequency subsyllables than when they resulted in high-frequency subsyllables, replicating the results from English-learning children.

  15. The Qualitative Expectations Hypothesis

    DEFF Research Database (Denmark)

    Frydman, Roman; Johansen, Søren; Rahbek, Anders

    2017-01-01

    We introduce the Qualitative Expectations Hypothesis (QEH) as a new approach to modeling macroeconomic and financial outcomes. Building on John Muth's seminal insight underpinning the Rational Expectations Hypothesis (REH), QEH represents the market's forecasts to be consistent with the predictions...... of an economistís model. However, by assuming that outcomes lie within stochastic intervals, QEH, unlike REH, recognizes the ambiguity faced by an economist and market participants alike. Moreover, QEH leaves the model open to ambiguity by not specifying a mechanism determining specific values that outcomes take...

  16. The Qualitative Expectations Hypothesis

    DEFF Research Database (Denmark)

    Frydman, Roman; Johansen, Søren; Rahbek, Anders

    We introduce the Qualitative Expectations Hypothesis (QEH) as a new approach to modeling macroeconomic and financial outcomes. Building on John Muth's seminal insight underpinning the Rational Expectations Hypothesis (REH), QEH represents the market's forecasts to be consistent with the predictions...... of an economist's model. However, by assuming that outcomes lie within stochastic intervals, QEH, unlike REH, recognizes the ambiguity faced by an economist and market participants alike. Moreover, QEH leaves the model open to ambiguity by not specifying a mechanism determining specific values that outcomes take...

  17. Do morphophonological rules impact both regular and irregular verb inflection? Evidence from acquired morphological impairment

    Directory of Open Access Journals (Sweden)

    Stacey Rimikis

    2015-05-01

    Full Text Available Introduction The role of morphophonological rules in production is a frequent point of contention in competing theories of morphological processing. Dual-mechanism theories have posited that a single default rule (stem+ed is used to produce the regular past tense, while all other past-tense forms are memorized and retrieved whole. However, research has suggested that a series of stochastic morphophonological rules plays a role in morphological productivity for both regular and irregular novel verbs (e.g. Albright & Hayes, 2003. Under this view, the likelihood of a given rule applying to a verb is partially dependent on its lexical support, measured as the number of phonologically similar verbs in the lexicon which take the same inflectional change (e.g. weep→wept, sweep→swept, etc.. To date, most evidence supporting this view has come from the morphological productivity of novel forms (e.g. Albright & Hayes, 2003 and from visual word recognition (Fruchter, Stockall, & Marantz, 2013. The present study extends this work by demonstrating that morphophonological rules impact production more generally, including the production of both regular and irregular past tense in RMI, an aphasic individual with an established morphological deficit (Rimikis & Buchwald, 2014. While we previously reported differences in production for irregular verbs with either high or low levels of lexical support, the current study further examined this phenomenon, and we found that the production of the past-tense form for both regular and irregular verbs was affected by the support for that verb’s inflectional rule . Subject RMI, 39, right-handed male with aphasia secondary to L-MCA CVA. His production includes frequent morphological errors across tasks, with semantic and phonological errors also occurring. Procedure RMI was administered a past-tense elicitation task. Sentence frames including regular and irregular verbs were presented verbally and visually (e.g.

  18. The Lehman Sisters Hypothesis

    NARCIS (Netherlands)

    I.P. van Staveren (Irene)

    2014-01-01

    markdownabstract__Abstract__ This article explores the Lehman Sisters Hypothesis. It reviews empirical literature about gender differences in behavioral, experimental, and neuro-economics as well as in other fields of behavioral research. It discusses gender differences along three dimensions of

  19. Revisiting the Dutch hypothesis

    NARCIS (Netherlands)

    Postma, Dirkje S.; Weiss, Scott T.; van den Berge, Maarten; Kerstjens, Huib A. M.; Koppelman, Gerard H.

    The Dutch hypothesis was first articulated in 1961, when many novel and advanced scientific techniques were not available, such as genomics techniques for pinpointing genes, gene expression, lipid and protein profiles, and the microbiome. In addition, computed tomographic scans and advanced analysis

  20. The Drift Burst Hypothesis

    OpenAIRE

    Christensen, Kim; Oomen, Roel; Renò, Roberto

    2016-01-01

    The Drift Burst Hypothesis postulates the existence of short-lived locally explosive trends in the price paths of financial assets. The recent US equity and Treasury flash crashes can be viewed as two high profile manifestations of such dynamics, but we argue that drift bursts of varying magnitude are an expected and regular occurrence in financial markets that can arise through established mechanisms such as feedback trading. At a theoretical level, we show how to build drift bursts into the...

  1. Bayesian Hypothesis Testing

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, Stephen A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sigeti, David E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-11-15

    These are a set of slides about Bayesian hypothesis testing, where many hypotheses are tested. The conclusions are the following: The value of the Bayes factor obtained when using the median of the posterior marginal is almost the minimum value of the Bayes factor. The value of τ2 which minimizes the Bayes factor is a reasonable choice for this parameter. This allows a likelihood ratio to be computed with is the least favorable to H0.

  2. The interactive brain hypothesis.

    Science.gov (United States)

    Di Paolo, Ezequiel; De Jaegher, Hanne

    2012-01-01

    Enactive approaches foreground the role of interpersonal interaction in explanations of social understanding. This motivates, in combination with a recent interest in neuroscientific studies involving actual interactions, the question of how interactive processes relate to neural mechanisms involved in social understanding. We introduce the Interactive Brain Hypothesis (IBH) in order to help map the spectrum of possible relations between social interaction and neural processes. The hypothesis states that interactive experience and skills play enabling roles in both the development and current function of social brain mechanisms, even in cases where social understanding happens in the absence of immediate interaction. We examine the plausibility of this hypothesis against developmental and neurobiological evidence and contrast it with the widespread assumption that mindreading is crucial to all social cognition. We describe the elements of social interaction that bear most directly on this hypothesis and discuss the empirical possibilities open to social neuroscience. We propose that the link between coordination dynamics and social understanding can be best grasped by studying transitions between states of coordination. These transitions form part of the self-organization of interaction processes that characterize the dynamics of social engagement. The patterns and synergies of this self-organization help explain how individuals understand each other. Various possibilities for role-taking emerge during interaction, determining a spectrum of participation. This view contrasts sharply with the observational stance that has guided research in social neuroscience until recently. We also introduce the concept of readiness to interact to describe the practices and dispositions that are summoned in situations of social significance (even if not interactive). This latter idea links interactive factors to more classical observational scenarios.

  3. The interactive brain hypothesis

    Directory of Open Access Journals (Sweden)

    Ezequiel Alejandro Di Paolo

    2012-06-01

    Full Text Available Enactive approaches foreground the role of interpersonal interaction in explanations of social understanding. This motivates, in combination with a recent interest in neuroscientific studies involving actual interactions, the question of how interactive processes relate to neural mechanisms involved in social understanding. We introduce the Interactive Brain Hypothesis in order to help map the possible relations between interaction and neural processes. The hypothesis states that interactive experience and skills play enabling roles in both the development and current function of social brain mechanisms, even in cases where social understanding happens in the absence of immediate interaction. We examine the plausibility of this hypothesis against developmental and neurobiological evidence and contrast it with the widespread assumption that mindreading is crucial to all social cognition. We describe the elements of social interaction that bear most directly on this hypothesis and discuss the empirical possibilities open to social neuroscience. We propose that the link between coordination dynamics and social understanding can be best grasped by studying transitions between states of coordination. These transitions form part of the self-organisation of interaction processes that characterise the dynamics of social engagement. The patterns and synergies of this self-organisation help explain how individuals understand each other. Various possibilities for role-taking emerge during interaction, determining a spectrum of participation. This view contrasts sharply with the observational stance that has guided research in social neuroscience until recently. We also introduce the concept of readiness to interact to describe the developed practices and dispositions that are summoned in situations of social significance (even if not interactive. This latter idea could link interactive factors to more classical observational scenarios.

  4. Hypothesis in research

    Directory of Open Access Journals (Sweden)

    Eudaldo Enrique Espinoza Freire

    2018-01-01

    Full Text Available It is intended with this work to have a material with the fundamental contents, which enable the university professor to formulate the hypothesis, for the development of an investigation, taking into account the problem to be solved. For its elaboration, the search of information in primary documents was carried out, such as thesis of degree and reports of research results, selected on the basis of its relevance with the analyzed subject, current and reliability, secondary documents, as scientific articles published in journals of recognized prestige, the selection was made with the same terms as in the previous documents. It presents a conceptualization of the updated hypothesis, its characterization and an analysis of the structure of the hypothesis in which the determination of the variables is deepened. The involvement of the university professor in the teaching-research process currently faces some difficulties, which are manifested, among other aspects, in an unstable balance between teaching and research, which leads to a separation between them.

  5. Prosodic constraints on inflected words: an area of difficulty for German-speaking children with specific language impairment?

    Science.gov (United States)

    Kauschke, Christina; Renner, Lena; Domahs, Ulrike

    2013-08-01

    Recent studies suggest that morphosyntactic difficulties may result from prosodic problems. We therefore address the interface between inflectional morphology and prosody in typically developing children (TD) and children with SLI by testing whether these groups are sensitive to prosodic constraints that guide plural formation in German. A plural elicitation task was designed consisting of 60 words and 20 pseudowords. The performance of 14 German-speaking children with SLI (mean age 7.5) was compared to age-matched controls and to younger children matched for productive vocabulary. TD children performed significantly better than children with SLI. Error analyses revealed that children with SLI produced more forms that did not meet the optimal shape of a noun plural. Beyond the fact that children with SLI have deficits in plural marking, the findings suggest that they also show reduced sensitivity to prosodic requirements. In other words, the prosodic structure of inflected words seems to be vulnerable in children with SLI.

  6. Disentangling Effects of Input Frequency and Morphophonological Complexity on Children's Acquisition of Verb Inflection: An Elicited Production Study of Japanese.

    Science.gov (United States)

    Tatsumi, Tomoko; Ambridge, Ben; Pine, Julian M

    2017-10-10

    This study aims to disentangle the often-confounded effects of input frequency and morphophonological complexity in the acquisition of inflection, by focusing on simple and complex verb forms in Japanese. Study 1 tested 28 children aged 3;3-4;3 on stative (complex) and simple past forms, and Study 2 tested 30 children aged 3;5-5;3 on completive (complex) and simple past forms, with both studies using a production priming paradigm. Mixed effects models for children's responses were built to test the prediction that children's verb use is explained by the relative bias in input frequency between the two inflectional forms. Although Study 1 did not show a significant effect of input bias (apparently due to problems with item selection), Study 2, which corrected for this problem, yielded the predicted relationship. These findings suggest that input frequency effects, at the level of different inflectional forms of the same verb stem, hold even after controlling for morphophonological complexity. © 2017 The Authors. Cognitive Science published by Wiley Periodicals, Inc. on behalf of Cognitive Science Society.

  7. The Voice of Holland: Allograph Production in Written Dutch Past Tense Inflection

    Science.gov (United States)

    de Bree, Elise; van der Ven, Sanne; van der Maas, Han

    2017-01-01

    According to the Integration of Multiple Patterns hypothesis (IMP; Treiman & Kessler, 2014), the spelling difficulty of a word is affected by the number of cues converging on the correct answer. We tested this hypothesis in children's regular past tense formation in Dutch. Past tenses are formed by adding either-"de"…

  8. The Voice of Holland : Allograph Production in Written Dutch Past Tense Inflection

    NARCIS (Netherlands)

    de Bree, E.; van der Ven, S.; van der Maas, H.

    2017-01-01

    According to the Integration of Multiple Patterns hypothesis (IMP; Treiman & Kessler, 2014), the spelling difficulty of a word is affected by the number of cues converging on the correct answer. We tested this hypothesis in children’s regular past tense formation in Dutch. Past tenses are formed by

  9. Physiologic time: A hypothesis

    Science.gov (United States)

    West, Damien; West, Bruce J.

    2013-06-01

    The scaling of respiratory metabolism with body size in animals is considered by many to be a fundamental law of nature. One apparent consequence of this law is the scaling of physiologic time with body size, implying that physiologic time is separate and distinct from clock time. Physiologic time is manifest in allometry relations for lifespans, cardiac cycles, blood volume circulation, respiratory cycle, along with a number of other physiologic phenomena. Herein we present a theory of physiologic time that explains the allometry relation between time and total body mass averages as entailed by the hypothesis that the fluctuations in the total body mass are described by a scaling probability density.

  10. Relations between the inflection point on the force-time curve and force-time parameters during static explosive grip.

    Science.gov (United States)

    Ikemoto, Yukio; Demura, Shinichi; Yamaji, Shunsuke

    2004-04-01

    Individual differences in muscle contractile speed during static explosive muscle contraction are reflected in the developmental phase of the force-time curve. The purposes of this study were to clarify the properties and reliability of the inflection point of force-time, statistically dividing speed during static explosive grip into two phases and to assess the relations between that inflection point and others. Static explosive grip data were measured two times with a 5-min. rest (sampling frequency; 100 Hz). 32 healthy, young men (age: 15.5 +/- 0.8 yr., height: 173.9 +/- 7.3 cm, body mass: 71.5 +/- 11.2 kg) participated. 8 static explosive grip parameters were selected: time of reaching, integrated area, and quotient values of the integrated areas up to 0.25, 0.5, and 1.0 sec. divided by maximal grip force. The inflection point was calculated statistically from two regression lines fitted to a developmental phase and the almost steady-state phase of reaching maximal grip force by applying a two-phase regression model. The reliabilities of maximal grip force, time of reaching 90% of maximal grip force, and the integrated area until 0.5 sec. and 1.0 sec. after the onset of grip were good (ICC=.77 to .93). The time of reaching an inflection force value appeared at 0.3 sec. after the onset of grip, corresponding to 80% of maximal grip force, and the reliabilities of the parameters regarding inflection point were good (ICC=.77 to .95). The time determined by boundary data between the former and the latter regression data set and the regression coefficient during the developmental phase correlated significantly with the time of reaching 90% of maximal grip force, the integrated area, and the quotient values of the integrated areas up to 0.25, 0.5, and 1.0 sec. divided by maximal grip force (rs=-.78 to -.96 and -.75 to 0.88, respectively, pforce. A force during the developmental phase and maximal grip force can depend on different physiological factors. The time

  11. Antiaging therapy: a prospective hypothesis

    Directory of Open Access Journals (Sweden)

    Shahidi Bonjar MR

    2015-01-01

    Full Text Available Mohammad Rashid Shahidi Bonjar,1 Leyla Shahidi Bonjar2 1School of Dentistry, Kerman University of Medical Sciences, Kerman Iran; 2Department of Pharmacology, College of Pharmacy, Kerman University of Medical Sciences, Kerman, Iran Abstract: This hypothesis proposes a new prospective approach to slow the aging process in older humans. The hypothesis could lead to developing new treatments for age-related illnesses and help humans to live longer. This hypothesis has no previous documentation in scientific media and has no protocol. Scientists have presented evidence that systemic aging is influenced by peculiar molecules in the blood. Researchers at Albert Einstein College of Medicine, New York, and Harvard University in Cambridge discovered elevated titer of aging-related molecules (ARMs in blood, which trigger cascade of aging process in mice; they also indicated that the process can be reduced or even reversed. By inhibiting the production of ARMs, they could reduce age-related cognitive and physical declines. The present hypothesis offers a new approach to translate these findings into medical treatment: extracorporeal adjustment of ARMs would lead to slower rates of aging. A prospective “antiaging blood filtration column” (AABFC is a nanotechnological device that would fulfill the central role in this approach. An AABFC would set a near-youth homeostatic titer of ARMs in the blood. In this regard, the AABFC immobilizes ARMs from the blood while blood passes through the column. The AABFC harbors antibodies against ARMs. ARM antibodies would be conjugated irreversibly to ARMs on contact surfaces of the reaction platforms inside the AABFC till near-youth homeostasis is attained. The treatment is performed with the aid of a blood-circulating pump. Similar to a renal dialysis machine, blood would circulate from the body to the AABFC and from there back to the body in a closed circuit until ARMs were sufficiently depleted from the blood. The

  12. Effect of Two Isolated Vocal-facilitating Techniques Chant Talk and Pitch Inflections on the Phonation of Female Speech-language Pathology Students: A Pilot Study.

    Science.gov (United States)

    Meerschman, Iris; Bettens, Kim; Dejagere, Stefanie; Tetaert, Lieselot; D'haeseleer, Evelien; Claeys, Sofie; Van Lierde, Kristiane

    2016-11-01

    The purpose of this study was to determine the effect of the isolated vocal-facilitating techniques Chant Talk and Pitch Inflections on the phonation of healthy female speech-language pathology (SLP) students. A multigroup pretest-posttest design was used. A homogenous group of 40 healthy female SLP students with a mean age of 18.7 years were randomly assigned into 3 groups: a Chant Talk group (practicing Chant Talk across 18 weeks), a Pitch Inflections group (practicing Pitch Inflections across 18 weeks), and a control group (practicing no facilitating techniques). To compare vocal measures before and after this time span, an identical objective voice assessment protocol (aerodynamic measurement, acoustic analysis, voice range profile, and Dysphonia Severity Index) was performed in the 3 groups. Both Chant Talk and Pitch Inflections groups resulted in a significant decrease of the acoustic measure noise-to-harmonics ratio compared with the control group. The Chant Talk group resulted in a significant increase in the acoustic measure fundamental frequency compared with the control group. The results of this pilot study suggest that the facilitating techniques Chant Talk and Pitch Inflections may improve the objective measure of breathiness (noise-to-harmonics ratio) in healthy female SLP students. Copyright © 2016 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  13. Homophonic forms of regularly inflected verbs have their own orthographic representations: a developmental perspective on spelling errors.

    Science.gov (United States)

    Frisson, Steven; Sandra, Dominiek

    2002-01-01

    In previous research (Sandra, Frisson, & Daems, 1999) we demonstrated that experienced writers of Dutch (18-year-olds) make spelling errors on regularly inflected homophonic verb forms. Intrusion errors, i.e., spelling of the homophonic alternative, occurred more often when the low-frequency homophone had to be written. In the present article we report error data for three groups of less experienced spellers, who have not yet fully mastered the rules for verb suffix spelling: 12-year-olds, 13-year-olds, and 14-year-olds. Younger spellers obviously make many more errors than experienced ones. Whereas this is in part due to inadequate rule mastery/application, their error patterns are also clearly influenced by the frequency relationship between the homophonic forms, i.e., the same factor accounting for the errors of experienced spellers. The conclusion of our present and past research is that homophonic forms of regularly inflected verbs have their own orthographic representations in the mental lexicon and that these representations cause interference in writing (spelling errors), whereas they might cause facilitation in reading (a claim made by dual-route models of reading). Copyright 2002 Elsevier Science (USA).

  14. Phonological and orthographic cues enhance the processing of inflectional morphology. ERP evidence from L1 and L2 French.

    Science.gov (United States)

    Carrasco-Ortiz, Haydee; Frenck-Mestre, Cheryl

    2014-01-01

    We report the results of two event-related potential (ERP) experiments in which Spanish learners of French and native French controls show graded sensitivity to verbal inflectional errors as a function of the presence of orthographic and/or phonological cues when reading silently in French. In both experiments, verbal agreement was manipulated in sentential context such that subject verb agreement was either correct, ill-formed and orally realized, involving both orthographic and phonological cues, or ill-formed and silent which involved only orthographic cues. The results of both experiments revealed more robust ERP responses to orally realized than to silent inflectional errors. This was true for L2 learners as well as native controls, although the effect in the learner group was reduced in comparison to the native group. In addition, the combined influence of phonological and orthographic cues led to the largest differences between syntactic/phonological conditions. Overall, the results suggest that the presence of phonological cues may enhance L2 readers' sensitivity to morphology but that such may appear in L2 processing only when sufficient proficiency is attained. Moreover, both orthographic and phonological cues are used when available.

  15. Phonological and orthographic cues enhance the processing of inflectional morphology. ERP evidence from L1 and L2 French

    Directory of Open Access Journals (Sweden)

    Haydee eCarrasco-Ortiz

    2014-08-01

    Full Text Available We report the results of two ERP experiments in which Spanish learners of French and native French controls show graded sensitivity to verbal inflectional errors as a function of the presence of orthographic and/or phonological cues when reading silently in French. In both experiments, verbal agreement was manipulated in sentential context such that subject verb agreement was either correct, ill-formed and orally-realized, involving both orthographic and phonological cues, or ill-formed and silent which involved only orthographic cues. The results of both experiments revealed more robust ERP responses to orally-realized than to silent inflectional errors. This was true for L2 learners as well as native controls, although the effect in the learner group was reduced in comparison to the native group. In addition, the combined influence of phonological and orthographic cues led to the largest differences between morphosyntactic conditions. Overall, the results suggest that the presence of phonological cues may enhance L2 readers’ sensitivity to morphology but that such may appear in L2 processing only when sufficient proficiency is attained. Moreover, both orthographic and phonological cues are used when available.

  16. Relationship of Grammatical Context on Children's Recognition of s/z-Inflected Words.

    Science.gov (United States)

    Spratford, Meredith; McLean, Hannah Hodson; McCreery, Ryan

    2017-10-01

    Access to aided high-frequency speech information is currently assessed behaviorally using recognition of plural monosyllabic words. Because of semantic and grammatical cues that support word+morpheme recognition in sentence materials, the contribution of high-frequency audibility to sentence recognition is less than that for isolated words. However, young children may not yet have the linguistic competence to take advantage of these cues. A low-predictability sentence recognition task that controls for language ability could be used to assess the impact of high-frequency audibility in a context that more closely represents how children learn language. To determine if differences exist in recognition of s/z-inflected monosyllabic words for children with normal hearing (CNH) and children who are hard of hearing (CHH) across stimuli context (presented in isolation versus embedded medially within a sentence that has low semantic and syntactic predictability) and varying levels of high-frequency audibility (4- and 8-kHz low-pass filtered for CNH and 8-kHz low-pass filtered for CHH). A prospective, cross-sectional design was used to analyze word+morpheme recognition in noise for stimuli varying in grammatical context and high-frequency audibility. Low-predictability sentence stimuli were created so that the target word+morpheme could not be predicted by semantic or syntactic cues. Electroacoustic measures of aided access to high-frequency speech sounds were used to predict individual differences in recognition for CHH. Thirty-five children, aged 5-12 yrs, were recruited to participate in the study; 24 CNH and 11 CHH (bilateral mild to severe hearing loss) who wore hearing aids (HAs). All children were native speakers of English. Monosyllabic word+morpheme recognition was measured in isolated and sentence-embedded conditions at a +10 dB signal-to-noise ratio using steady state, speech-shaped noise. Real-ear probe microphone measures of HAs were obtained for CHH. To

  17. Verbal Inflectional Morphology in L1 and L2 Spanish: A Frequency Effects Study Examining Storage versus Composition

    Science.gov (United States)

    Bowden, Harriet Wood; Gelfand, Matthew P.; Sanz, Cristina; Ullman, Michael T.

    2009-01-01

    This study examines the storage vs. composition of Spanish inflected verbal forms in L1 and L2 speakers of Spanish. L2 participants were selected to have mid-to-advanced proficiency, high classroom experience, and low immersion experience, typical of medium-to-advanced foreign language learners. Participants were shown the infinitival forms of verbs from either Class I (the default class, which takes new verbs) or Classes II and III (non-default classes), and were asked to produce either first-person singular present-tense or imperfect forms, in separate tasks. In the present tense, the L1 speakers showed inflected-form frequency effects (i.e., higher frequency forms were produced faster, which is taken as a reflection of storage) for stem-changing (irregular) verb-forms from both Class I (e.g., pensar-pienso) and Classes II and III (e.g., perder-pierdo), as well as for non-stem-changing (regular) forms in Classes II/III (e.g., vender-vendo), in which the regular transformation does not appear to constitute a default. In contrast, Class I regulars (e.g., pescar-pesco), whose non-stem-changing transformation constitutes a default (e.g., it is applied to new verbs), showed no frequency effects. L2 speakers showed frequency effects for all four conditions (Classes I and II/III, regulars and irregulars). In the imperfect tense, the L1 speakers showed frequency effects for Class II/III (-ía-suffixed) but not Class I (-aba-suffixed) forms, even though both involve non-stem-change (regular) default transformations. The L2 speakers showed frequency effects for both types of forms. The pattern of results was not explained by a wide range of potentially confounding experimental and statistical factors, and does not appear to be compatible with single-mechanism models, which argue that all linguistic forms are learned and processed in associative memory. The findings are consistent with a dual-system view in which both verb class and regularity influence the storage vs

  18. Verbal Inflectional Morphology in L1 and L2 Spanish: A Frequency Effects Study Examining Storage versus Composition.

    Science.gov (United States)

    Bowden, Harriet Wood; Gelfand, Matthew P; Sanz, Cristina; Ullman, Michael T

    2010-02-17

    This study examines the storage vs. composition of Spanish inflected verbal forms in L1 and L2 speakers of Spanish. L2 participants were selected to have mid-to-advanced proficiency, high classroom experience, and low immersion experience, typical of medium-to-advanced foreign language learners. Participants were shown the infinitival forms of verbs from either Class I (the default class, which takes new verbs) or Classes II and III (non-default classes), and were asked to produce either first-person singular present-tense or imperfect forms, in separate tasks. In the present tense, the L1 speakers showed inflected-form frequency effects (i.e., higher frequency forms were produced faster, which is taken as a reflection of storage) for stem-changing (irregular) verb-forms from both Class I (e.g., pensar-pienso) and Classes II and III (e.g., perder-pierdo), as well as for non-stem-changing (regular) forms in Classes II/III (e.g., vender-vendo), in which the regular transformation does not appear to constitute a default. In contrast, Class I regulars (e.g., pescar-pesco), whose non-stem-changing transformation constitutes a default (e.g., it is applied to new verbs), showed no frequency effects. L2 speakers showed frequency effects for all four conditions (Classes I and II/III, regulars and irregulars). In the imperfect tense, the L1 speakers showed frequency effects for Class II/III (-ía-suffixed) but not Class I (-aba-suffixed) forms, even though both involve non-stem-change (regular) default transformations. The L2 speakers showed frequency effects for both types of forms. The pattern of results was not explained by a wide range of potentially confounding experimental and statistical factors, and does not appear to be compatible with single-mechanism models, which argue that all linguistic forms are learned and processed in associative memory. The findings are consistent with a dual-system view in which both verb class and regularity influence the storage vs

  19. Is the Aluminum Hypothesis Dead?

    Science.gov (United States)

    2014-01-01

    The Aluminum Hypothesis, the idea that aluminum exposure is involved in the etiology of Alzheimer disease, dates back to a 1965 demonstration that aluminum causes neurofibrillary tangles in the brains of rabbits. Initially the focus of intensive research, the Aluminum Hypothesis has gradually been abandoned by most researchers. Yet, despite this current indifference, the Aluminum Hypothesis continues to attract the attention of a small group of scientists and aluminum continues to be viewed with concern by some of the public. This review article discusses reasons that mainstream science has largely abandoned the Aluminum Hypothesis and explores a possible reason for some in the general public continuing to view aluminum with mistrust. PMID:24806729

  20. Identifying transitions in finite systems by means of partition function zeros and microcanonical inflection-point analysis: a comparison for elastic flexible polymers.

    Science.gov (United States)

    Rocha, Julio C S; Schnabel, Stefan; Landau, David P; Bachmann, Michael

    2014-08-01

    For the estimation of transition points of finite elastic, flexible polymers with chain lengths from 13 to 309 monomers, we compare systematically transition temperatures obtained by the Fisher partition function zeros approach with recent results from microcanonical inflection-point analysis. These methods rely on accurate numerical estimates of the density of states, which have been obtained by advanced multicanonical Monte Carlo sampling techniques. Both the Fisher zeros method and microcanonical inflection-point analysis yield very similar results and enable the unique identification of transition points in finite systems, which is typically impossible in the conventional canonical analysis of thermodynamic quantities.

  1. Hypothesis Validity of Clinical Research.

    Science.gov (United States)

    Wampold, Bruce E.; And Others

    1990-01-01

    Describes hypothesis validity as extent to which research results reflect theoretically derived predictions about relations between or among constructs. Discusses role of hypotheses in theory testing. Presents four threats to hypothesis validity: (1) inconsequential research hypotheses; (2) ambiguous research hypotheses; (3) noncongruence of…

  2. Surface Tension of Supercooled Water: Inflection Point-Free Course down to 250 K Confirmed Using a Horizontal Capillary Tube

    Czech Academy of Sciences Publication Activity Database

    Vinš, Václav; Hošek, Jan; Hykl, Jiří; Hrubý, Jan

    2017-01-01

    Roč. 62, č. 11 (2017), s. 3823-3832 ISSN 0021-9568 R&D Projects: GA ČR(CZ) GJ15-07129Y Institutional support: RVO:61388998 Keywords : horizontal technique * metastable liquid * supercooled Subject RIV: BJ - Thermodynamics OBOR OECD: Thermodynamics Impact factor: 2.323, year: 2016 http://pubs.acs.org/doi/pdf/10.1021/acs.jced.7b00519

  3. Language modeling for automatic speech recognition of inflective languages an applications-oriented approach using lexical data

    CERN Document Server

    Donaj, Gregor

    2017-01-01

    This book covers language modeling and automatic speech recognition for inflective languages (e.g. Slavic languages), which represent roughly half of the languages spoken in Europe. These languages do not perform as well as English in speech recognition systems and it is therefore harder to develop an application with sufficient quality for the end user. The authors describe the most important language features for the development of a speech recognition system. This is then presented through the analysis of errors in the system and the development of language models and their inclusion in speech recognition systems, which specifically address the errors that are relevant for targeted applications. The error analysis is done with regard to morphological characteristics of the word in the recognized sentences. The book is oriented towards speech recognition with large vocabularies and continuous and even spontaneous speech. Today such applications work with a rather small number of languages compared to the nu...

  4. Observation and investigation of a dynamic inflection point in current-voltage curves for roll-to-roll processed polymer photovoltaics

    DEFF Research Database (Denmark)

    Medford, Andrew James; Lilliedal, Mathilde Raad

    2010-01-01

    Inflection point behaviour is often observed in the current-voltage (IV) curve of polymer and organic solar cells. This phenomenon is examined in the context of flexible roll-to-roll (R2R) processed polymer solar cells in a large series of devices with a layer structure of: PET-ITO-ZnO-P3HT...

  5. Homophone Dominance at the Whole-Word and Sub-Word Levels: Spelling Errors Suggest Full-Form Storage of Regularly Inflected Verb Forms

    Science.gov (United States)

    Sandra, Dominiek

    2010-01-01

    Two experiments and two corpus studies focus on homophone dominance in the spelling of regularly inflected verb forms, the phenomenon that the higher-frequency homophone causes more intrusion errors on the lower-frequency one than vice versa. Experiment 1 was a speeded dictation task focusing on the Dutch imperative, a verb form whose formation…

  6. The effect of post-processing treatments on inflection points in current–voltage curves of roll-to-roll processed polymer photovoltaics

    DEFF Research Database (Denmark)

    Lilliedal, Mathilde Raad; Medford, Andrew James; Vesterager Madsen, Morten

    2010-01-01

    Inflection point behaviour is often observed in the current–voltage (IV) curve of polymer solar cells. This phenomenon is examined in the context of flexible roll-to-roll (R2R) processed polymer solar cells in a large series of devices with a layer structure of: PET–ITO–ZnO–P3HT:PCBM–PEDOT:PSS–Ag...

  7. The Low-Temperature Inflection Observed in Neutron Scattering Measurements of Proteins Is Due to Methyl Rotation : Direct Evidence Using Isotope Labeling and Molecular Dynamics Simulations

    NARCIS (Netherlands)

    Wood, Kathleen; Tobias, Douglas J.; Kessler, Brigitte; Gabel, Frank; Oesterhelt, Dieter; Mulder, Frans A. A.; Zaccai, Giuseppe; Weik, Martin

    2010-01-01

    There is increasing interest in the contribution of methyl groups to the overall dynamics measured by neutron scattering experiments of proteins. In particular an inflection observed in atomic mean square displacements measured as a function of temperature on high resolution spectrometers (similar

  8. Between L2 and SLI: Inflections and Prepositions in the Hebrew of Bilingual Children with TLD and Monolingual Children with SLI

    Science.gov (United States)

    Armon-Lotem, Sharon

    2014-01-01

    Verb inflectional morphology and prepositions are loci of difficulty for bilingual children with typical language development (TLD) as well as children with Specific Language Impairment (SLI). This paper examines errors in these linguistic domains in these two populations. Bilingual English-Hebrew and Russian-Hebrew preschool children, aged five…

  9. Testing One Hypothesis Multiple times

    OpenAIRE

    Algeri, Sara; van Dyk, David A.

    2017-01-01

    Hypothesis testing in presence of a nuisance parameter that is only identifiable under the alternative is challenging in part because standard asymptotic results (e.g., Wilks theorem for the generalized likelihood ratio test) do not apply. Several solutions have been proposed in the statistical literature and their practical implementation often reduces the problem into one of Testing One Hypothesis Multiple times (TOHM). Specifically, a fine discretization of the space of the non-identifiabl...

  10. Differential recall of derived and inflected word forms in working memory: Examining the role of morphological information in simple and complex working memory tasks

    Directory of Open Access Journals (Sweden)

    Elisabet eService

    2015-01-01

    Full Text Available Working memory has been described as an interface between cognition and action, or a system for access to a limited amount of information needed in complex cognition. Access to morphological information is needed for comprehending and producing sentences. The present study probed working memory for morphologically complex word forms in Finnish, a morphologically rich language. We studied monomorphemic (boy, inflected (boy+’s and derived (boy+hood words in three tasks. Simple span, immediate serial recall of words, in Experiment 1, is assumed to mainly rely on information in the focus of attention. Sentence span, a dual task combining sentence reading with recall of the last word (Experiment 2 or of a word not included in the sentence (Experiment 3 is assumed to involve establishment of a search set in long-term memory for fast activation into the focus of attention. Recall was best for monomorphemic and worst for inflected word forms with performance on derived words in between. However, there was an interaction between word type and experiment, suggesting that complex span is more sensitive to morphological complexity in derivations than simple span. This was explored in a within-subjects Experiment 4 combining all three tasks. An interaction between morphological complexity and task was replicated. Both inflected and derived forms increased load in working memory. In simple span, recall of inflectional forms resulted in form errors. Complex span tasks were more sensitive to morphological load in derived words, possibly resulting from interference from morphological neighbors in the mental lexicon. The results are best understood as involving competition among inflectional forms when binding words from input into an output structure, and competition from morphological neighbors in secondary memory during cumulative retrieval-encoding cycles. Models of verbal recall need to be able to represent morphological as well as phonological and

  11. 5-HTP hypothesis of schizophrenia.

    Science.gov (United States)

    Fukuda, K

    2014-01-01

    To pose a new hypothesis of schizophrenia that affirms and unifies conventional hypotheses. Outside the brain, there are 5-HTP-containing argyrophil cells that have tryptophan hydroxylase 1 without l-aromatic amino acid decarboxylase. Monoamine oxidase in the liver and lung metabolize 5-HT, rather than 5-HTP, and 5-HTP freely crosses the blood-brain barrier, converting to 5-HT in the brain. Therefore I postulate that hyperfunction of 5-HTP-containing argyrophil cells may be a cause of schizophrenia. I investigate the consistency of this hypothesis with other hypotheses using a deductive method. Overactive 5-HTP-containing argyrophil cells produce excess amounts of 5-HTP. Abundant 5-HTP increases 5-HT within the brain (linking to the 5-HT hypothesis), and leads to negative feedback of 5-HT synthesis at the rate-limiting step catalysed by tryptophan hydroxylase 2. Owing to this negative feedback, brain tryptophan is further metabolized via the kynurenine pathway. Increased kynurenic acid contributes to deficiencies of glutamate function and dopamine activity, known causes of schizophrenia. The 5-HTP hypothesis affirms conventional hypotheses, as the metabolic condition caused by acceleration of tryptophan hydroxylase 1 and suppression of tryptophan hydroxylase 2, activates both 5-HT and kynurenic acid. In order to empirically test the theory, it will be useful to monitor serum 5-HTP and match it to different phases of schizophrenia. This hypothesis may signal a new era with schizophrenia treated as a brain-gut interaction. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. The atomic hypothesis: physical consequences

    International Nuclear Information System (INIS)

    Rivas, Martin

    2008-01-01

    The hypothesis that matter is made of some ultimate and indivisible objects, together with the restricted relativity principle, establishes a constraint on the kind of variables we are allowed to use for the variational description of elementary particles. We consider that the atomic hypothesis not only states the indivisibility of elementary particles, but also that these ultimate objects, if not annihilated, cannot be modified by any interaction so that all allowed states of an elementary particle are only kinematical modifications of any one of them. Therefore, an elementary particle cannot have excited states. In this way, the kinematical group of spacetime symmetries not only defines the symmetries of the system, but also the variables in terms of which the mathematical description of the elementary particles can be expressed in either the classical or the quantum mechanical description. When considering the interaction of two Dirac particles, the atomic hypothesis restricts the interaction Lagrangian to a kind of minimal coupling interaction

  13. The regulation of the air: a hypothesis

    Directory of Open Access Journals (Sweden)

    E. G. Nisbet

    2012-03-01

    Full Text Available We propose the hypothesis that natural selection, acting on the specificity or preference for CO2 over O2 of the enzyme rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase, has controlled the CO2:O2 ratio of the atmosphere since the evolution of photosynthesis and has also sustained the Earth's greenhouse-set surface temperature. Rubisco works in partnership with the nitrogen-fixing enzyme nitrogenase to control atmospheric pressure. Together, these two enzymes control global surface temperature and indirectly the pH and oxygenation of the ocean. Thus, the co-evolution of these two enzymes may have produced clement conditions on the Earth's surface, allowing life to be sustained.

  14. Discussion of the Porter hypothesis

    International Nuclear Information System (INIS)

    1999-11-01

    In the reaction to the long-range vision of RMNO, published in 1996, The Dutch government posed the question whether a far-going and progressive modernization policy will lead to competitive advantages of high-quality products on partly new markets. Such a question is connected to the so-called Porter hypothesis: 'By stimulating innovation, strict environmental regulations can actually enhance competitiveness', from which statement it can be concluded that environment and economy can work together quite well. A literature study has been carried out in order to determine under which conditions that hypothesis is endorsed in the scientific literature and policy documents. Recommendations are given for further studies. refs

  15. The thrifty phenotype hypothesis revisited

    DEFF Research Database (Denmark)

    Vaag, A A; Grunnet, L G; Arora, G P

    2012-01-01

    Twenty years ago, Hales and Barker along with their co-workers published some of their pioneering papers proposing the 'thrifty phenotype hypothesis' in Diabetologia (4;35:595-601 and 3;36:62-67). Their postulate that fetal programming could represent an important player in the origin of type 2...... of the underlying molecular mechanisms. Type 2 diabetes is a multiple-organ disease, and developmental programming, with its idea of organ plasticity, is a plausible hypothesis for a common basis for the widespread organ dysfunctions in type 2 diabetes and the metabolic syndrome. Only two among the 45 known type 2...

  16. Testing the egocentric mirror-rotation hypothesis.

    Science.gov (United States)

    Muelenz, Cornelius; Hecht, Heiko; Gamer, Matthias

    2010-01-01

    Although observers know about the law of reflection, their intuitive understanding of spatial locations in mirrors is often erroneous. Hecht et al. (2005) proposed a two-stage mirror-rotation hypothesis to explain these misconceptions. The hypothesis involves an egocentric bias to the effect that observers behave as if the mirror surface were rotated by about 2 degrees to be more orthogonal than is the case. We test four variants of the hypothesis, which differ depending on whether the virtual world, the mirror, or both are taken to be rotated. We devised an experimental setup that allowed us to distinguish between these variants. Our results confirm that the virtual world--and only the virtual world--is being rotated. Observers had to perform a localization task, using a mirror that was either fronto-parallel or rotated opposite the direction of the predicted effect. We were thus able to compensate for the effect. The positions of objects in mirrors were perceived in accordance with the erroneous conception that the virtual world behind the mirror is slightly rotated and that the reconstruction is based on the non-rotated fronto-parallel mirror. A covert rotation of the mirror by about 2 degrees against the predicted effect was able to compensate for the placement error.

  17. The low-temperature inflection observed in neutron scattering measurements of proteins is due to methyl rotation: direct evidence using isotope labeling and molecular dynamics simulations.

    Science.gov (United States)

    Wood, Kathleen; Tobias, Douglas J; Kessler, Brigitte; Gabel, Frank; Oesterhelt, Dieter; Mulder, Frans A A; Zaccai, Giuseppe; Weik, Martin

    2010-04-14

    There is increasing interest in the contribution of methyl groups to the overall dynamics measured by neutron scattering experiments of proteins. In particular an inflection observed in atomic mean square displacements measured as a function of temperature on high resolution spectrometers (approximately 1 microeV) was explained by the onset of methyl group rotations. By specifically labeling a non-methyl-containing side-chain in a native protein system, the purple membrane, and performing neutron scattering measurements, we here provide direct experimental evidence that the observed inflection is indeed due to methyl group rotations. Molecular dynamics simulations reproduce the experimental data, and their analysis suggests that the apparent transition is due to methyl group rotation entering the finite instrumental resolution of the spectrometer. Methyl group correlation times measured by solid state NMR in the purple membrane, taken from previous work, support the interpretation.

  18. Hypersonic boundary layer in the vicinity of a point of inflection of leading edge on a flat wing in the regime of strong viscous interaction

    Science.gov (United States)

    Dudin, G. N.; Ledovskiy, A. V.

    2013-06-01

    The flow in a spatial hypersonic laminar boundary layer on a planar wing with a point of inflection in the leading edge is considered in the regime of strong viscous-inviscid interaction. The boundary problems are formulated for two cases: self-similar flow near the point of inflection of the leading edge and full three-dimensional (3D) boundary layer on a wing with variable sweep angle. The numerical solution is obtained using the finite-difference method. The results of parametric calculations of influence of a wing shape and the temperature factor on flow characteristics in the boundary layer are presented. The possibility of formation of local regions with high shear stress and heat flux is shown.

  19. The power of imageability: How the acquisition of inflected forms is facilitated in highly imageable verbs and nouns in Czech children

    Czech Academy of Sciences Publication Activity Database

    Smolík, Filip; Kříž, A.

    2015-01-01

    Roč. 35, č. 6 (2015), s. 446-465 ISSN 0142-7237 R&D Projects: GA ČR GA13-26779S Institutional support: RVO:68081740 Keywords : acquisition of inflections * imageability * language acquisition * grammar acquisition * morphology Subject RIV: AN - Psychology Impact factor: 1.254, year: 2015 http://fla.sagepub.com/content/35/6/446.full.pdf+html

  20. Syntactic Dependencies and Verbal Inflection: Complementisers and Verbal Forms in Standard Arabic

    Directory of Open Access Journals (Sweden)

    Feras Saeed

    2015-12-01

    Full Text Available This paper investigates the syntactic dependency between complementisers and verbal forms in Standard Arabic and provides a new analysis of this dependency. The imperfective verb in this language surfaces with three different forms, where each form is indicated by a different suffixal marker attached to the end of the verb as (-u, (-a, or (-Ø. The occurrence of each suffixal marker on the verb corresponds to the co-occurrence of a particular type of Comp-elements in the C/T domain. I argue that these morphological markers on the three verbal forms are the manifestation of an Agree relation between an interpretable unvalued finiteness feature [Fin] on C and an uninterpretable but valued instance of the same feature on v, assuming feature transfer and feature sharing between C/T and v (Pesetsky & Torrego 2007; Chomsky 2008. I also argue that the different verbal forms in Standard Arabic are dictated by the co-occurrence of three types of Comp-elements: i C-elements; ii T-elements which ultimately move to C; and iii imperative/negative elements. Keywords: feature transfer/sharing, verbal forms, complementisers, finiteness, syntactic dependency, Standard Arabic

  1. A Molecular–Structure Hypothesis

    Directory of Open Access Journals (Sweden)

    Jan C. A. Boeyens

    2010-11-01

    Full Text Available The self-similar symmetry that occurs between atomic nuclei, biological growth structures, the solar system, globular clusters and spiral galaxies suggests that a similar pattern should characterize atomic and molecular structures. This possibility is explored in terms of the current molecular structure-hypothesis and its extension into four-dimensional space-time. It is concluded that a quantum molecule only has structure in four dimensions and that classical (Newtonian structure, which occurs in three dimensions, cannot be simulated by quantum-chemical computation.

  2. A durkheimian hypothesis on stress.

    Science.gov (United States)

    Mestrovic, S; Glassner, B

    1983-01-01

    Commonalities among the events that appear on life events lists and among the types of social supports which have been found to reduce the likelihood of illness are reviewed in the life events literature in an attempt to find a context within sociological theory. Social integration seems to underlie the stress-illness process. In seeking a tradition from which to understand these facts, we selected Durkheim's works in the context of the homo duplex concept wherein social integration involves the interplay of individualism and social forces. After presenting a specific hypothesis for the stress literature, the paper concludes with implications and suggestions for empirical research.

  3. Unit cell hypothesis for Streptococcus faecalis.

    Science.gov (United States)

    Edelstein, E M; Rosenzweig, M S; Daneo-Moore, L; Higgins, M L

    1980-07-01

    The mass doubling times of exponential-phase cultures of Streptococcus faecalis were varied from 30 to 110 min by omitting glutamine from a defined growth medium and providing different concentrations of glutamate (ranging from 300 to 14 mug/ml). After Formalin fixation, cells were dried by the critical point method, and carbon-platinum replicas were prepared. The surface area and volume of cell poles seen in these replicas were estimated by a computer-assisted, three-dimensional reconstruction technique. It was found that the amount of surface area and volume of poles seen in these replicas were independent of the growth rate of culture from which the samples were taken. These observations were consistent with the unit cell model hypothesis of Donachie and Begg, in which a small number of surface sites would produce a constant amount of new cell surface regardless of the mass doubling time of the culture. However, measurements of the thickness of the cell wall taken from thin sections of the same cells showed that the cell wall increased in thickness as a function of the increase in cellular peptidoglycan content which occurs when the growth rate of this organism is slowed down by a decrease in glutamate concentration. Thus, it would seem that although the size of polar shells made by S. faecalis is invariant with growth rate, the amount of wall precursors used to construct these shells is not.

  4. Ecological Hypothesis of Dentin and Root Caries.

    Science.gov (United States)

    Takahashi, Nobuhiro; Nyvad, Bente

    2016-01-01

    Recent advances regarding the caries process indicate that ecological phenomena induced by bacterial acid production tilt the de- and remineralization balance of the dental hard tissues towards demineralization through bacterial acid-induced adaptation and selection within the microbiota - from the dynamic stability stage to the aciduric stage via the acidogenic stage [Takahashi and Nyvad, 2008]. Dentin and root caries can also be partly explained by this hypothesis; however, the fact that these tissues contain a considerable amount of organic material suggests that protein degradation is involved in caries formation. In this review, we compiled relevant histological, biochemical, and microbiological information about dentin/root caries and refined the hypothesis by adding degradation of the organic matrix (the proteolytic stage) to the abovementioned stages. Bacterial acidification not only induces demineralization and exposure of the organic matrix in dentin/root surfaces but also activation of dentin-embedded and salivary matrix metalloproteinases and cathepsins. These phenomena initiate degradation of the demineralized organic matrix in dentin/root surfaces. While a bacterial involvement has never been confirmed in the initial degradation of organic material, the detection of proteolytic/amino acid-degrading bacteria and bacterial metabolites in dentin and root caries suggests a bacterial digestion and metabolism of partly degraded matrix. Moreover, bacterial metabolites might induce pulpitis as an inflammatory/immunomodulatory factor. Root and dentin surfaces are always at risk of becoming demineralized in the oral cavity, and exposed organic materials can be degraded by host-derived proteases contained in saliva and dentin itself. New approaches to the prevention and treatment of root/dentin caries are required. © 2016 S. Karger AG, Basel.

  5. Is PMI the Hypothesis or the Null Hypothesis?

    Science.gov (United States)

    Tarone, Aaron M; Sanford, Michelle R

    2017-09-01

    Over the past several decades, there have been several strident exchanges regarding whether forensic entomologists estimate the postmortem interval (PMI), minimum PMI, or something else. During that time, there has been a proliferation of terminology reflecting this concern regarding "what we do." This has been a frustrating conversation for some in the community because much of this debate appears to be centered on what assumptions are acknowledged directly and which are embedded within a list of assumptions (or ignored altogether) in the literature and in case reports. An additional component of the conversation centers on a concern that moving away from the use of certain terminology like PMI acknowledges limitations and problems that would make the application of entomology appear less useful in court-a problem for lawyers, but one that should not be problematic for scientists in the forensic entomology community, as uncertainty is part of science that should and can be presented effectively in the courtroom (e.g., population genetic concepts in forensics). Unfortunately, a consequence of the way this conversation is conducted is that even as all involved in the debate acknowledge the concerns of their colleagues, parties continue to talk past one another advocating their preferred terminology. Progress will not be made until the community recognizes that all of the terms under consideration take the form of null hypothesis statements and that thinking about "what we do" as a null hypothesis has useful legal and scientific ramifications that transcend arguments over the usage of preferred terminology. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. A TEST OF THE ADDITIVITY OF ACUTE TOXICITY OF BINARY-METAL MIXTURES OF NI WITH CD, CU, AND ZN TO DAPHNIA MAGNA, USING THE INFLECTION POINT OF THE CONCENTRATION–RESPONSE CURVES

    Science.gov (United States)

    Traudt, Elizabeth M.; Ranville, James F.; Smith, Samantha A.; Meyer, Joseph S.

    2018-01-01

    Mixtures of metals are often present in surface waters, leading to toxicity that is difficult to predict. To provide data for development of multimetal toxicity models, Daphnia magna neonates were exposed to individual metals (Cd, Cu, Ni, Zn) and to binary combinations of those metals in standard 48-h lethality tests conducted in US Environmental Protection Agency moderately hard reconstituted water with 3 mg dissolved organic carbon (DOC)/L added as Suwannee River fulvic acid. Toxicity tests were performed with mixtures of Ni and 1) Cd, which is considerably more toxic than Ni; 2) Cu, which is less toxic than Cd but more toxic than Ni; and 3) Zn, which has a toxicity threshold similar to Ni. For each combination of metals in the binary mixtures, the concentration of 1 metal was held constant while the second metal was varied through a series that ranged from nonlethal to lethal concentrations; then the roles of the metals were reversed. Inflection points of the concentration–response curves were compared to test for additivity of toxicity. Sublethal concentrations of Ni caused less-than-additive toxicity with Cd, slightly less-than-additive toxicity with Zn, and greater-than-additive toxicity with Cu. One explanation of these results might be competition among the metals for binding to biological ligands and/or dissolved organic matter. Therefore, models might have to incorporate sometimes competing chemical interactions to accurately predict metal-mixture toxicity. PMID:26681657

  7. Metabolic syndrome--neurotrophic hypothesis.

    Science.gov (United States)

    Hristova, M; Aloe, L

    2006-01-01

    An increasing number of researchers of the metabolic syndrome assume that many mechanisms are involved in its complex pathophysiology such as an increased sympathetic activity, disorders of the hypothalamo-pituitary-adrenal axis, the action of chronic subclinical infections, proinflammatory cytokines, and the effect of adipocytokines or psychoemotional stress. An increasing body of scientific research in this field confirms the role of the neurotrophins and mastocytes in the pathogenesis of inflammatory and immune diseases. Recently it has been proved that neurotrophins and mastocytes have metabotrophic effects and take part in the carbohydrate and lipid metabolism. In the early stage of the metabolic syndrome we established a statistically significant increase in the plasma levels of the nerve growth factor. In the generalized stage the plasma levels of the neutrophines were statistically decreased in comparison to those in the healthy controls. We consider that the neurotrophin deficit is likely to play a significant pathogenic role in the development of the metabolic anthropometric and vascular manifestations of the generalized stage of MetSyn. We suggest a hypothesis for the etiopathogenesis of the metabolic syndrome based on the neuro-immuno-endocrine interactions. The specific pathogenic pathways of MetSyn development include: (1) increased tissue and plasma levels of proinflammatory cytokines Interleukin-1(IL-1), Interleukin-6 (IL-6 ) and tumor necrosis factor - alpha (TNF-alpha) caused by inflammatory and/or emotional distress; (2) increased plasma levels of neurotrophin - nerve growth factor (NGF) caused by the high IL-1, IL-6 and TNFalpha levels; (3) high plasma levels of NGF which enhance activation of: the autonomous nerve system--vegetodystonia (disbalance of neurotransmitters); Neuropeptide Y (NPY)--enhanced feeding, obesity and increased leptin plasma levels; hypothalamo-pituitary-adrenal axis--increased corticotropin-releasing hormone (CRH) and

  8. Memory in astrocytes: a hypothesis

    Directory of Open Access Journals (Sweden)

    Caudle Robert M

    2006-01-01

    Full Text Available Abstract Background Recent work has indicated an increasingly complex role for astrocytes in the central nervous system. Astrocytes are now known to exchange information with neurons at synaptic junctions and to alter the information processing capabilities of the neurons. As an extension of this trend a hypothesis was proposed that astrocytes function to store information. To explore this idea the ion channels in biological membranes were compared to models known as cellular automata. These comparisons were made to test the hypothesis that ion channels in the membranes of astrocytes form a dynamic information storage device. Results Two dimensional cellular automata were found to behave similarly to ion channels in a membrane when they function at the boundary between order and chaos. The length of time information is stored in this class of cellular automata is exponentially related to the number of units. Therefore the length of time biological ion channels store information was plotted versus the estimated number of ion channels in the tissue. This analysis indicates that there is an exponential relationship between memory and the number of ion channels. Extrapolation of this relationship to the estimated number of ion channels in the astrocytes of a human brain indicates that memory can be stored in this system for an entire life span. Interestingly, this information is not affixed to any physical structure, but is stored as an organization of the activity of the ion channels. Further analysis of two dimensional cellular automata also demonstrates that these systems have both associative and temporal memory capabilities. Conclusion It is concluded that astrocytes may serve as a dynamic information sink for neurons. The memory in the astrocytes is stored by organizing the activity of ion channels and is not associated with a physical location such as a synapse. In order for this form of memory to be of significant duration it is necessary

  9. The oxidative hypothesis of senescence

    Directory of Open Access Journals (Sweden)

    Gilca M

    2007-01-01

    Full Text Available The oxidative hypothesis of senescence, since its origin in 1956, has garnered significant evidence and growing support among scientists for the notion that free radicals play an important role in ageing, either as "damaging" molecules or as signaling molecules. Age-increasing oxidative injuries induced by free radicals, higher susceptibility to oxidative stress in short-lived organisms, genetic manipulations that alter both oxidative resistance and longevity and the anti-ageing effect of caloric restriction and intermittent fasting are a few examples of accepted scientific facts that support the oxidative theory of senescence. Though not completely understood due to the complex "network" of redox regulatory systems, the implication of oxidative stress in the ageing process is now well documented. Moreover, it is compatible with other current ageing theories (e.g., those implicating the mitochondrial damage/mitochondrial-lysosomal axis, stress-induced premature senescence, biological "garbage" accumulation, etc. This review is intended to summarize and critically discuss the redox mechanisms involved during the ageing process: sources of oxidant agents in ageing (mitochondrial -electron transport chain, nitric oxide synthase reaction- and non-mitochondrial- Fenton reaction, microsomal cytochrome P450 enzymes, peroxisomal β -oxidation and respiratory burst of phagocytic cells, antioxidant changes in ageing (enzymatic- superoxide dismutase, glutathione-reductase, glutathion peroxidase, catalase- and non-enzymatic glutathione, ascorbate, urate, bilirubine, melatonin, tocopherols, carotenoids, ubiquinol, alteration of oxidative damage repairing mechanisms and the role of free radicals as signaling molecules in ageing.

  10. Robust and distributed hypothesis testing

    CERN Document Server

    Gül, Gökhan

    2017-01-01

    This book generalizes and extends the available theory in robust and decentralized hypothesis testing. In particular, it presents a robust test for modeling errors which is independent from the assumptions that a sufficiently large number of samples is available, and that the distance is the KL-divergence. Here, the distance can be chosen from a much general model, which includes the KL-divergence as a very special case. This is then extended by various means. A minimax robust test that is robust against both outliers as well as modeling errors is presented. Minimax robustness properties of the given tests are also explicitly proven for fixed sample size and sequential probability ratio tests. The theory of robust detection is extended to robust estimation and the theory of robust distributed detection is extended to classes of distributions, which are not necessarily stochastically bounded. It is shown that the quantization functions for the decision rules can also be chosen as non-monotone. Finally, the boo...

  11. The venom optimization hypothesis revisited.

    Science.gov (United States)

    Morgenstern, David; King, Glenn F

    2013-03-01

    Animal venoms are complex chemical mixtures that typically contain hundreds of proteins and non-proteinaceous compounds, resulting in a potent weapon for prey immobilization and predator deterrence. However, because venoms are protein-rich, they come with a high metabolic price tag. The metabolic cost of venom is sufficiently high to result in secondary loss of venom whenever its use becomes non-essential to survival of the animal. The high metabolic cost of venom leads to the prediction that venomous animals may have evolved strategies for minimizing venom expenditure. Indeed, various behaviors have been identified that appear consistent with frugality of venom use. This has led to formulation of the "venom optimization hypothesis" (Wigger et al. (2002) Toxicon 40, 749-752), also known as "venom metering", which postulates that venom is metabolically expensive and therefore used frugally through behavioral control. Here, we review the available data concerning economy of venom use by animals with either ancient or more recently evolved venom systems. We conclude that the convergent nature of the evidence in multiple taxa strongly suggests the existence of evolutionary pressures favoring frugal use of venom. However, there remains an unresolved dichotomy between this economy of venom use and the lavish biochemical complexity of venom, which includes a high degree of functional redundancy. We discuss the evidence for biochemical optimization of venom as a means of resolving this conundrum. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Alien abduction: a medical hypothesis.

    Science.gov (United States)

    Forrest, David V

    2008-01-01

    In response to a new psychological study of persons who believe they have been abducted by space aliens that found that sleep paralysis, a history of being hypnotized, and preoccupation with the paranormal and extraterrestrial were predisposing experiences, I noted that many of the frequently reported particulars of the abduction experience bear more than a passing resemblance to medical-surgical procedures and propose that experience with these may also be contributory. There is the altered state of consciousness, uniformly colored figures with prominent eyes, in a high-tech room under a round bright saucerlike object; there is nakedness, pain and a loss of control while the body's boundaries are being probed; and yet the figures are thought benevolent. No medical-surgical history was apparently taken in the above mentioned study, but psychological laboratory work evaluated false memory formation. I discuss problems in assessing intraoperative awareness and ways in which the medical hypothesis could be elaborated and tested. If physicians are causing this syndrome in a percentage of patients, we should know about it; and persons who feel they have been abducted should be encouraged to inform their surgeons and anesthesiologists without challenging their beliefs.

  13. The Younger Dryas impact hypothesis: A requiem

    Science.gov (United States)

    Pinter, Nicholas; Scott, Andrew C.; Daulton, Tyrone L.; Podoll, Andrew; Koeberl, Christian; Anderson, R. Scott; Ishman, Scott E.

    2011-06-01

    consistent with the diffuse, non-catastrophic input of micrometeorite ablation fallout, probably augmented by anthropogenic and other terrestrial spherular grains. Results here also show considerable subjectivity in the reported sampling methods that may explain the purported YD spherule concentration peaks. Fire is a pervasive earth-surface process, and reanalyses of the original YD sites and of coeval records show episodic fire on the landscape through the latest Pleistocene, with no unique fire event at the onset of the YD. Lastly, with YD impact proponents increasingly retreating to nanodiamonds (cubic, hexagonal [lonsdaleite], and the proposed n-diamond) as evidence of impact, those data have been called into question. The presence of lonsdaleite was reported as proof of impact-related shock processes, but the evidence presented was inconsistent with lonsdaleite and consistent instead with polycrystalline aggregates of graphene and graphane mixtures that are ubiquitous in carbon forms isolated from sediments ranging from modern to pre-YD age. Important questions remain regarding the origins and distribution of other diamond forms (e.g., cubic nanodiamonds). In summary, none of the original YD impact signatures have been subsequently corroborated by independent tests. Of the 12 original lines of evidence, seven have so far proven to be non-reproducible. The remaining signatures instead seem to represent either (1) non-catastrophic mechanisms, and/or (2) terrestrial rather than extraterrestrial or impact-related sources. In all of these cases, sparse but ubiquitous materials seem to have been misreported and misinterpreted as singular peaks at the onset of the YD. Throughout the arc of this hypothesis, recognized and expected impact markers were not found, leading to proposed YD impactors and impact processes that were novel, self-contradictory, rapidly changing, and sometimes defying the laws of physics. The YD impact hypothesis provides a cautionary tale for researchers

  14. Spectral analysis and the Riemann hypothesis

    Science.gov (United States)

    Lachaud, Gilles

    2003-11-01

    The explicit formulas of Riemann and Guinand-Weil relate the set of prime numbers with the set of nontrivial zeros of the zeta function of Riemann. We recall Alain Connes' spectral interpretation of the critical zeros of the Riemann zeta function as eigenvalues of the absorption spectrum of an unbounded operator in a suitable Hilbert space. We then give a spectral interpretation of the zeros of the Dedekind zeta function of an algebraic number field K of degree n in an automorphic setting. If K is a complex quadratic field, the torical forms are the functions defined on the modular surface X, such that the sum of this function over the "Gauss set" of K is zero, and Eisenstein series provide such torical forms. In the case of a general number field, one can associate to K a maximal torus T of the general linear group G. The torical forms are the functions defined on the modular variety X associated to G, such that the integral over the subvariety induced by T is zero. Alternately, the torical forms are the functions which are orthogonal to orbital series on X. We show here that the Riemann hypothesis is equivalent to certain conditions bearing on spaces of torical forms, constructed from Eisenstein series, the torical wave packets. Furthermore, we define a Hilbert space and a self-adjoint operator on this space, whose spectrum equals the set of critical zeros of the Dedekind zeta function of K.

  15. Marginal contrasts and the Contrastivist Hypothesis

    Directory of Open Access Journals (Sweden)

    Daniel Currie Hall

    2016-12-01

    Full Text Available The Contrastivist Hypothesis (CH; Hall 2007; Dresher 2009 holds that the only features that can be phonologically active in any language are those that serve to distinguish phonemes, which presupposes that phonemic status is categorical. Many researchers, however, demonstrate the existence of gradient relations. For instance, Hall (2009 quantifies these using the information-theoretic measure of entropy (unpredictability of distribution and shows that a pair of sounds may have an entropy between 0 (totally predictable and 1 (totally unpredictable. We argue that the existence of such intermediate degrees of contrastiveness does not make the CH untenable, but rather offers insight into contrastive hierarchies. The existence of a continuum does not preclude categorical distinctions: a categorical line can be drawn between zero entropy (entirely predictable, and thus by the CH phonologically inactive and non-zero entropy (at least partially contrastive, and thus potentially phonologically active. But this does not mean that intermediate degrees of surface contrastiveness are entirely irrelevant to the CH; rather, we argue, they can shed light on how deeply ingrained a phonemic distinction is in the phonological system. As an example, we provide a case study from Pulaar [ATR] harmony, which has previously been claimed to be problematic for the CH.

  16. Transpiration: A Test of Optimality Hypothesis

    Science.gov (United States)

    Wang, J.; Bras, R. L.; Lerdau, M.; Salvucci, G. D.; Wofsy, S.

    2003-12-01

    The argument is that the fundamental mechanisms behind bare soil evaporation are also responsible for plant transpiration except that stomata affect the exchange of water vapor between the evaporating surface and the atmosphere. It is hypothesized that the system of liquid water in leaf tissues and the water vapor in the atmosphere tries to evolve towards a potential equilibrium as quickly as possible by maximizing transpiration. In the proposed theory, CO2 flux is used as a non-parametric equivalent of stomatal conductance as CO2 and water vapor diffuse in and out of leaves through the same path. It is further assumed that stomatal aperture is directly controlled by guard cell turgor (or leaf water potential). Transpiration is formulated as a function of leaf temperature, leaf water potential/stomatal conductance (or CO2 flux as the surrogate), and sensible heat flux (characterizing transport mechanism) at a given level of radiative energy input. Optimization of transpiration constrained by the energy balance equation leads to vanishing derivatives of transpiration with respect to leaf temperature and CO2 flux. Effect of vapor pressure deficit on transpiration is also investigated. Preliminary tests using field experimental measurements lead to encouraging evidence in support of the hypothesis. It is found that transpiration is fairly insensitive to atmospheric humidity as suggested by several earlier studies.

  17. Teaching hypothesis testing: a necessary challenge

    NARCIS (Netherlands)

    Post, Wendy J.; van Duijn, Marijtje A.J.; Makar, Katie; de Sousa, Bruno; Gould, Robert

    The last decades a debate has been going on about the use of hypothesis testing. This has led some teachers to think that confidence intervals and effect sizes need to be taught instead of formal hypothesis testing with p-values. Although we see shortcomings of the use of p-values in statistical

  18. Hypothesis elimination on a quantum computer

    OpenAIRE

    Soklakov, Andrei N.; Schack, Ruediger

    2004-01-01

    Hypothesis elimination is a special case of Bayesian updating, where each piece of new data rules out a set of prior hypotheses. We describe how to use Grover's algorithm to perform hypothesis elimination for a class of probability distributions encoded on a register of qubits, and establish a lower bound on the required computational resources.

  19. Mastery Learning and the Decreasing Variability Hypothesis.

    Science.gov (United States)

    Livingston, Jennifer A.; Gentile, J. Ronald

    1996-01-01

    This report results from studies that tested two variations of Bloom's decreasing variability hypothesis using performance on successive units of achievement in four graduate classrooms that used mastery learning procedures. Data do not support the decreasing variability hypothesis; rather, they show no change over time. (SM)

  20. Hypothesis Testing in the Real World

    Science.gov (United States)

    Miller, Jeff

    2017-01-01

    Critics of null hypothesis significance testing suggest that (a) its basic logic is invalid and (b) it addresses a question that is of no interest. In contrast to (a), I argue that the underlying logic of hypothesis testing is actually extremely straightforward and compelling. To substantiate that, I present examples showing that hypothesis…

  1. Error probabilities in default Bayesian hypothesis testing

    NARCIS (Netherlands)

    Gu, Xin; Hoijtink, Herbert; Mulder, J,

    2016-01-01

    This paper investigates the classical type I and type II error probabilities of default Bayes factors for a Bayesian t test. Default Bayes factors quantify the relative evidence between the null hypothesis and the unrestricted alternative hypothesis without needing to specify prior distributions for

  2. Predictions from high scale mixing unification hypothesis

    Indian Academy of Sciences (India)

    2016-01-09

    Jan 9, 2016 ... Starting with 'high scale mixing unification' hypothesis, we investigate the renormalization group evolution of mixing parameters and masses for both Dirac and Majorana-type neutrinos. Following this hypothesis, the PMNS mixing parameters are taken to be identical to the CKM ones at a unifying high ...

  3. Hypothesis testing in hydrology: Theory and practice

    Science.gov (United States)

    Kirchner, James; Pfister, Laurent

    2017-04-01

    Well-posed hypothesis tests have spurred major advances in hydrological theory. However, a random sample of recent research papers suggests that in hydrology, as in other fields, hypothesis formulation and testing rarely correspond to the idealized model of the scientific method. Practices such as "p-hacking" or "HARKing" (Hypothesizing After the Results are Known) are major obstacles to more rigorous hypothesis testing in hydrology, along with the well-known problem of confirmation bias - the tendency to value and trust confirmations more than refutations - among both researchers and reviewers. Hypothesis testing is not the only recipe for scientific progress, however: exploratory research, driven by innovations in measurement and observation, has also underlain many key advances. Further improvements in observation and measurement will be vital to both exploratory research and hypothesis testing, and thus to advancing the science of hydrology.

  4. Knowledge dimensions in hypothesis test problems

    Science.gov (United States)

    Krishnan, Saras; Idris, Noraini

    2012-05-01

    The reformation in statistics education over the past two decades has predominantly shifted the focus of statistical teaching and learning from procedural understanding to conceptual understanding. The emphasis of procedural understanding is on the formulas and calculation procedures. Meanwhile, conceptual understanding emphasizes students knowing why they are using a particular formula or executing a specific procedure. In addition, the Revised Bloom's Taxonomy offers a twodimensional framework to describe learning objectives comprising of the six revised cognition levels of original Bloom's taxonomy and four knowledge dimensions. Depending on the level of complexities, the four knowledge dimensions essentially distinguish basic understanding from the more connected understanding. This study identifiesthe factual, procedural and conceptual knowledgedimensions in hypothesis test problems. Hypothesis test being an important tool in making inferences about a population from sample informationis taught in many introductory statistics courses. However, researchers find that students in these courses still have difficulty in understanding the underlying concepts of hypothesis test. Past studies also show that even though students can perform the hypothesis testing procedure, they may not understand the rationale of executing these steps or know how to apply them in novel contexts. Besides knowing the procedural steps in conducting a hypothesis test, students must have fundamental statistical knowledge and deep understanding of the underlying inferential concepts such as sampling distribution and central limit theorem. By identifying the knowledge dimensions of hypothesis test problems in this study, suitable instructional and assessment strategies can be developed in future to enhance students' learning of hypothesis test as a valuable inferential tool.

  5. Implications of the Bohm-Aharonov hypothesis

    International Nuclear Information System (INIS)

    Ghirardi, G.C.; Rimini, A.; Weber, T.

    1976-01-01

    It is proved that the Bohm-Aharonov hypothesis concerning largerly separated subsystems of composite quantum systems implies that it is impossible to express the dynamical evolution in terms of the density operator

  6. Sleep memory processing: the sequential hypothesis

    OpenAIRE

    Giuditta, Antonio

    2014-01-01

    According to the sequential hypothesis (SH) memories acquired during wakefulness are processed during sleep in two serial steps respectively occurring during slow wave sleep (SWS) and rapid eye movement (REM) sleep. During SWS memories to be retained are distinguished from irrelevant or competing traces that undergo downgrading or elimination. Processed memories are stored again during REM sleep which integrates them with preexisting memories. The hypothesis received support from a wealth of ...

  7. Multiple hypothesis tracking for the cyber domain

    Science.gov (United States)

    Schwoegler, Stefan; Blackman, Sam; Holsopple, Jared; Hirsch, Michael J.

    2011-09-01

    This paper discusses how methods used for conventional multiple hypothesis tracking (MHT) can be extended to domain-agnostic tracking of entities from non-kinematic constraints such as those imposed by cyber attacks in a potentially dense false alarm background. MHT is widely recognized as the premier method to avoid corrupting tracks with spurious data in the kinematic domain but it has not been extensively applied to other problem domains. The traditional approach is to tightly couple track maintenance (prediction, gating, filtering, probabilistic pruning, and target confirmation) with hypothesis management (clustering, incompatibility maintenance, hypothesis formation, and Nassociation pruning). However, by separating the domain specific track maintenance portion from the domain agnostic hypothesis management piece, we can begin to apply the wealth of knowledge gained from ground and air tracking solutions to the cyber (and other) domains. These realizations led to the creation of Raytheon's Multiple Hypothesis Extensible Tracking Architecture (MHETA). In this paper, we showcase MHETA for the cyber domain, plugging in a well established method, CUBRC's INFormation Engine for Real-time Decision making, (INFERD), for the association portion of the MHT. The result is a CyberMHT. We demonstrate the power of MHETA-INFERD using simulated data. Using metrics from both the tracking and cyber domains, we show that while no tracker is perfect, by applying MHETA-INFERD, advanced nonkinematic tracks can be captured in an automated way, perform better than non-MHT approaches, and decrease analyst response time to cyber threats.

  8. Aminoglycoside antibiotics and autism: a speculative hypothesis

    Directory of Open Access Journals (Sweden)

    Manev Hari

    2001-10-01

    Full Text Available Abstract Background Recently, it has been suspected that there is a relationship between therapy with some antibiotics and the onset of autism; but even more curious, some children benefited transiently from a subsequent treatment with a different antibiotic. Here, we speculate how aminoglycoside antibiotics might be associated with autism. Presentation We hypothesize that aminoglycoside antibiotics could a trigger the autism syndrome in susceptible infants by causing the stop codon readthrough, i.e., a misreading of the genetic code of a hypothetical critical gene, and/or b improve autism symptoms by correcting the premature stop codon mutation in a hypothetical polymorphic gene linked to autism. Testing Investigate, retrospectively, whether a link exists between aminoglycoside use (which is not extensive in children and the onset of autism symptoms (hypothesis "a", or between amino glycoside use and improvement of these symptoms (hypothesis "b". Whereas a prospective study to test hypothesis "a" is not ethically justifiable, a study could be designed to test hypothesis "b". Implications It should be stressed that at this stage no direct evidence supports our speculative hypothesis and that its main purpose is to initiate development of new ideas that, eventually, would improve our understanding of the pathobiology of autism.

  9. Morphological Errors in Spanish Second Language Learners and Heritage Speakers

    Science.gov (United States)

    Montrul, Silvina

    2011-01-01

    Morphological variability and the source of these errors have been intensely debated in SLA. A recurrent finding is that postpuberty second language (L2) learners often omit or use the wrong affix for nominal and verbal inflections in oral production but less so in written tasks. According to the missing surface inflection hypothesis, L2 learners…

  10. Reassessing the Trade-off Hypothesis

    DEFF Research Database (Denmark)

    Rosas, Guillermo; Manzetti, Luigi

    2015-01-01

    Do economic conditions drive voters to punish politicians that tolerate corruption? Previous scholarly work contends that citizens in young democracies support corrupt governments that are capable of promoting good economic outcomes, the so-called trade-off hypothesis. We test this hypothesis based...... on mass surveys in eighteen Latin American countries throughout 2004–2012. We find that citizens that report bribe attempts from bureaucrats are always more likely to report presidential disapproval than citizens that report no such attempts, that is, Latin American victims of corruption are not duped...... by good economic performance. However, we find some evidence for a weaker form of the trade-off hypothesis: presidential disapproval among corruption victims might be more pronounced in contexts of high inflation and high unemployment....

  11. Multi-hypothesis distributed stereo video coding

    DEFF Research Database (Denmark)

    Salmistraro, Matteo; Zamarin, Marco; Forchhammer, Søren

    2013-01-01

    for stereo sequences, exploiting an interpolated intra-view SI and two inter-view SIs. The quality of the SI has a major impact on the DVC Rate-Distortion (RD) performance. As the inter-view SIs individually present lower RD performance compared with the intra-view SI, we propose multi-hypothesis decoding...... for robust fusion and improved performance. Compared with a state-of-the-art single side information solution, the proposed DVC decoder improves the RD performance for all the chosen test sequences by up to 0.8 dB. The proposed multi-hypothesis decoder showed higher robustness compared with other fusion...

  12. Ready for Retirement: The Gateway Drug Hypothesis.

    Science.gov (United States)

    Kleinig, John

    2015-01-01

    The psycho-social observation that the use of some psychoactive substances ("drugs") is often followed by the use of other and more problematic drugs has given rise to a cluster of so-called "gateway drug hypotheses," and such hypotheses have often played an important role in developing drug use policy. The current essay suggests that drug use policies that have drawn on versions of the hypothesis have involved an unjustified oversimplification of the dynamics of drug use, reflecting the interests of certain stakeholders rather than wise social policy. The hypothesis should be retired.

  13. The discovered preference hypothesis - an empirical test

    DEFF Research Database (Denmark)

    Lundhede, Thomas; Ladenburg, Jacob; Olsen, Søren Bøye

    Using stated preference methods for valuation of non-market goods is known to be vulnerable to a range of biases. Some authors claim that these so-called anomalies in effect render the methods useless for the purpose. However, the Discovered Preference Hypothesis, as put forth by Plott [31], offe...

  14. The Hypothesis of Incommensurability and Multicultural Education

    Science.gov (United States)

    McDonough, Tim

    2009-01-01

    This article describes the logical and rhetorical grounds for a multicultural pedagogy that teaches students the knowledge and skills needed to interact creatively in the public realm betwixt and between cultures. I begin by discussing the notion of incommensurability. I contend that this hypothesis was intended to perform a particular rhetorical…

  15. Sleep memory processing: the sequential hypothesis.

    Science.gov (United States)

    Giuditta, Antonio

    2014-01-01

    According to the sequential hypothesis (SH) memories acquired during wakefulness are processed during sleep in two serial steps respectively occurring during slow wave sleep (SWS) and rapid eye movement (REM) sleep. During SWS memories to be retained are distinguished from irrelevant or competing traces that undergo downgrading or elimination. Processed memories are stored again during REM sleep which integrates them with preexisting memories. The hypothesis received support from a wealth of EEG, behavioral, and biochemical analyses of trained rats. Further evidence was provided by independent studies of human subjects. SH basic premises, data, and interpretations have been compared with corresponding viewpoints of the synaptic homeostatic hypothesis (SHY). Their similarities and differences are presented and discussed within the framework of sleep processing operations. SHY's emphasis on synaptic renormalization during SWS is acknowledged to underline a key sleep effect, but this cannot marginalize sleep's main role in selecting memories to be retained from downgrading traces, and in their integration with preexisting memories. In addition, SHY's synaptic renormalization raises an unsolved dilemma that clashes with the accepted memory storage mechanism exclusively based on modifications of synaptic strength. This difficulty may be bypassed by the assumption that SWS-processed memories are stored again by REM sleep in brain subnuclear quantum particles. Storing of memories in quantum particles may also occur in other vigilance states. Hints are provided on ways to subject the quantum hypothesis to experimental tests.

  16. [Resonance hypothesis of heart rate variability origin].

    Science.gov (United States)

    Sheĭkh-Zade, Iu R; Mukhambetaliev, G Kh; Cherednik, I L

    2009-09-01

    A hypothesis is advanced of the heart rate variability being subjected to beat-to-beat regulation of cardiac cycle duration in order to ensure the resonance interaction between respiratory and own fluctuation of the arterial system volume for minimization of power expenses of cardiorespiratory system. Myogenic, parasympathetic and sympathetic machanisms of heart rate variability are described.

  17. Hypothesis on the nature of atmospheric UFOs

    Science.gov (United States)

    Mukharev, L. A.

    1991-08-01

    A hypothesis is developed according to which the atmospheric UFO phenomenon has an electromagnetic nature. It is suggested that an atmospheric UFO is an agglomeration of charged atmospheric dust within which there exists a slowly damped electromagnetic field. This field is considered to be the source of the observed optical effects and the motive force of the UFO.

  18. Multiple hypothesis clustering in radar plot extraction

    NARCIS (Netherlands)

    Huizing, A.G.; Theil, A.; Dorp, Ph. van; Ligthart, L.P.

    1995-01-01

    False plots and plots with inaccurate range and Doppler estimates may severely degrade the performance of tracking algorithms in radar systems. This paper describes how a multiple hypothesis clustering technique can be applied to mitigate the problems involved in plot extraction. The measures of

  19. The (not so immortal strand hypothesis

    Directory of Open Access Journals (Sweden)

    Cristian Tomasetti

    2015-03-01

    Significance: Utilizing an approach that is fundamentally different from previous efforts to confirm or refute the immortal strand hypothesis, we provide evidence against non-random segregation of DNA during stem cell replication. Our results strongly suggest that parental DNA is passed randomly to stem cell daughters and provides new insight into the mechanism of DNA replication in stem cells.

  20. Forty Years Later: Updating the Fossilization Hypothesis

    Science.gov (United States)

    Han, ZhaoHong

    2013-01-01

    A founding concept in second language acquisition (SLA) research, fossilization has been fundamental to understanding second language (L2) development. The Fossilization Hypothesis, introduced in Selinker's seminal text (1972), has thus been one of the most influential theories, guiding a significant bulk of SLA research for four decades; 2012…

  1. Remarks about the hypothesis of limiting fragmentation

    International Nuclear Information System (INIS)

    Chou, T.T.; Yang, C.N.

    1987-01-01

    Remarks are made about the hypothesis of limiting fragmentation. In particular, the concept of favored and disfavored fragment distribution is introduced. Also, a sum rule is proved leading to a useful quantity called energy-fragmentation fraction. (author). 11 refs, 1 fig., 2 tabs

  2. Sleep memory processing: the sequential hypothesis

    Directory of Open Access Journals (Sweden)

    Antonio eGiuditta

    2014-12-01

    Full Text Available According to the sequential hypothesis (SH memories acquired during wakefulness are processed during sleep in two serial steps respectively occurring during slow wave sleep (SWS and REM sleep. During SWS memories to be retained are distinguished from irrelevant or competing traces that undergo downgrading or elimination. Processed memories are stored again during REM sleep which integrates them with preexisting memories. The hypothesis received support from a wealth of EEG, behavioral, and biochemical analyses of trained rats. Further evidence was provided by independent studies of human subjects. SH basic premises, data, and interpretations have been compared with corresponding viewpoints of the synaptic homeostatic hypothesis (SHY. Their similarities and differences are presented and discussed within the framework of sleep processing operations. SHY’s emphasis on synaptic renormalization during SWS is acknowledged to underline a key sleep effect, but this cannot marginalize sleep’s main role in selecting memories to be retained from downgrading traces, and in their integration with preexisting memories. In addition, SHY’s synaptic renormalization raises an unsolved dilemma that clashes with the accepted memory storage mechanism exclusively based on modifications of synaptic strength. This difficulty may be bypassed by the assumption that SWS-processed memories are stored again by REM sleep in brain subnuclear quantum particles. Storing of memories in quantum particles may also occur in other vigilance states. Hints are provided on ways to subject the quantum hypothesis to experimental tests.

  3. Television Exposure Measures and the Cultivation Hypothesis.

    Science.gov (United States)

    Potter, W. James; Chang, Ik Chin

    1990-01-01

    Describes study of students in grades 8 through 12 that was conducted to determine the degree to which television messages influence a person's construction of reality (the cultivation hypothesis). Research methodology that tests the effects of television exposure is examined with emphasis on the importance of demographic control variables. (38…

  4. Commentary: Human papillomavirus and tar hypothesis for ...

    Indian Academy of Sciences (India)

    2010-08-09

    Aug 9, 2010 ... Commentary: Human papillomavirus and tar hypothesis for squamous cell cervical cancer. Christina Bennett Allen E Kuhn Harry W Haverkos. Volume 35 Issue 3 September 2010 pp ... Keywords. Cervical cancer; co-factors; human papillomavirus; tar-based vaginal douche; tobacco smoke; wood smoke ...

  5. Morbidity and Infant Development: A Hypothesis.

    Science.gov (United States)

    Pollitt, Ernesto

    1983-01-01

    Results of a study conducted in 14 villages of Sui Lin Township, Taiwan, suggest the hypothesis that, under conditions of extreme economic impoverishment and among children within populations where energy protein malnutrition is endemic, there is an inverse relationship between incidence of morbidity in infancy and measures of motor and mental…

  6. The Income Inequality Hypothesis Revisited : Assessing the Hypothesis Using Four Methodological Approaches

    NARCIS (Netherlands)

    Kragten, N.; Rözer, J.

    The income inequality hypothesis states that income inequality has a negative effect on individual’s health, partially because it reduces social trust. This article aims to critically assess the income inequality hypothesis by comparing several analytical strategies, namely OLS regression,

  7. Cortical Neural Computation by Discrete Results Hypothesis.

    Science.gov (United States)

    Castejon, Carlos; Nuñez, Angel

    2016-01-01

    One of the most challenging problems we face in neuroscience is to understand how the cortex performs computations. There is increasing evidence that the power of the cortical processing is produced by populations of neurons forming dynamic neuronal ensembles. Theoretical proposals and multineuronal experimental studies have revealed that ensembles of neurons can form emergent functional units. However, how these ensembles are implicated in cortical computations is still a mystery. Although cell ensembles have been associated with brain rhythms, the functional interaction remains largely unclear. It is still unknown how spatially distributed neuronal activity can be temporally integrated to contribute to cortical computations. A theoretical explanation integrating spatial and temporal aspects of cortical processing is still lacking. In this Hypothesis and Theory article, we propose a new functional theoretical framework to explain the computational roles of these ensembles in cortical processing. We suggest that complex neural computations underlying cortical processing could be temporally discrete and that sensory information would need to be quantized to be computed by the cerebral cortex. Accordingly, we propose that cortical processing is produced by the computation of discrete spatio-temporal functional units that we have called "Discrete Results" (Discrete Results Hypothesis). This hypothesis represents a novel functional mechanism by which information processing is computed in the cortex. Furthermore, we propose that precise dynamic sequences of "Discrete Results" is the mechanism used by the cortex to extract, code, memorize and transmit neural information. The novel "Discrete Results" concept has the ability to match the spatial and temporal aspects of cortical processing. We discuss the possible neural underpinnings of these functional computational units and describe the empirical evidence supporting our hypothesis. We propose that fast-spiking (FS

  8. Einstein's Revolutionary Light-Quantum Hypothesis

    Science.gov (United States)

    Stuewer, Roger H.

    2005-05-01

    The paper in which Albert Einstein proposed his light-quantum hypothesis was the only one of his great papers of 1905 that he himself termed ``revolutionary.'' Contrary to widespread belief, Einstein did not propose his light-quantum hypothesis ``to explain the photoelectric effect.'' Instead, he based his argument for light quanta on the statistical interpretation of the second law of thermodynamics, with the photoelectric effect being only one of three phenomena that he offered as possible experimental support for it. I will discuss Einstein's light-quantum hypothesis of 1905 and his introduction of the wave-particle duality in 1909 and then turn to the reception of his work on light quanta by his contemporaries. We will examine the reasons that prominent physicists advanced to reject Einstein's light-quantum hypothesis in succeeding years. Those physicists included Robert A. Millikan, even though he provided convincing experimental proof of the validity of Einstein's equation of the photoelectric effect in 1915. The turning point came after Arthur Holly Compton discovered the Compton effect in late 1922, but even then Compton's discovery was contested both on experimental and on theoretical grounds. Niels Bohr, in particular, had never accepted the reality of light quanta and now, in 1924, proposed a theory, the Bohr-Kramers-Slater theory, which assumed that energy and momentum were conserved only statistically in microscopic interactions. Only after that theory was disproved experimentally in 1925 was Einstein's revolutionary light-quantum hypothesis generally accepted by physicists---a full two decades after Einstein had proposed it.

  9. The Method of Hypothesis in Plato's Philosophy

    Directory of Open Access Journals (Sweden)

    Malihe Aboie Mehrizi

    2016-09-01

    Full Text Available The article deals with the examination of method of hypothesis in Plato's philosophy. This method, respectively, will be examined in three dialogues of Meno, Phaedon and Republic in which it is explicitly indicated. It will be shown the process of change of Plato’s attitude towards the position and usage of the method of hypothesis in his realm of philosophy. In Meno, considering the geometry, Plato attempts to introduce a method that can be used in the realm of philosophy. But, ultimately in Republic, Plato’s special attention to the method and its importance in the philosophical investigations, leads him to revise it. Here, finally Plato introduces the particular method of philosophy, i.e., the dialectic

  10. Reverse hypothesis machine learning a practitioner's perspective

    CERN Document Server

    Kulkarni, Parag

    2017-01-01

    This book introduces a paradigm of reverse hypothesis machines (RHM), focusing on knowledge innovation and machine learning. Knowledge- acquisition -based learning is constrained by large volumes of data and is time consuming. Hence Knowledge innovation based learning is the need of time. Since under-learning results in cognitive inabilities and over-learning compromises freedom, there is need for optimal machine learning. All existing learning techniques rely on mapping input and output and establishing mathematical relationships between them. Though methods change the paradigm remains the same—the forward hypothesis machine paradigm, which tries to minimize uncertainty. The RHM, on the other hand, makes use of uncertainty for creative learning. The approach uses limited data to help identify new and surprising solutions. It focuses on improving learnability, unlike traditional approaches, which focus on accuracy. The book is useful as a reference book for machine learning researchers and professionals as ...

  11. Testing competing forms of the Milankovitch hypothesis

    DEFF Research Database (Denmark)

    Kaufmann, Robert K.; Juselius, Katarina

    2016-01-01

    We test competing forms of the Milankovitch hypothesis by estimating the coefficients and diagnostic statistics for a cointegrated vector autoregressive model that includes 10 climate variables and four exogenous variables for solar insolation. The estimates are consistent with the physical...... ice volume and solar insolation. The estimated adjustment dynamics show that solar insolation affects an array of climate variables other than ice volume, each at a unique rate. This implies that previous efforts to test the strong form of the Milankovitch hypothesis by examining the relationship...... mechanisms postulated to drive glacial cycles. They show that the climate variables are driven partly by solar insolation, determining the timing and magnitude of glaciations and terminations, and partly by internal feedback dynamics, pushing the climate variables away from equilibrium. We argue...

  12. Multi-agent sequential hypothesis testing

    KAUST Repository

    Kim, Kwang-Ki K.

    2014-12-15

    This paper considers multi-agent sequential hypothesis testing and presents a framework for strategic learning in sequential games with explicit consideration of both temporal and spatial coordination. The associated Bayes risk functions explicitly incorporate costs of taking private/public measurements, costs of time-difference and disagreement in actions of agents, and costs of false declaration/choices in the sequential hypothesis testing. The corresponding sequential decision processes have well-defined value functions with respect to (a) the belief states for the case of conditional independent private noisy measurements that are also assumed to be independent identically distributed over time, and (b) the information states for the case of correlated private noisy measurements. A sequential investment game of strategic coordination and delay is also discussed as an application of the proposed strategic learning rules.

  13. Exploring heterogeneous market hypothesis using realized volatility

    Science.gov (United States)

    Chin, Wen Cheong; Isa, Zaidi; Mohd Nor, Abu Hassan Shaari

    2013-04-01

    This study investigates the heterogeneous market hypothesis using high frequency data. The cascaded heterogeneous trading activities with different time durations are modelled by the heterogeneous autoregressive framework. The empirical study indicated the presence of long memory behaviour and predictability elements in the financial time series which supported heterogeneous market hypothesis. Besides the common sum-of-square intraday realized volatility, we also advocated two power variation realized volatilities in forecast evaluation and risk measurement in order to overcome the possible abrupt jumps during the credit crisis. Finally, the empirical results are used in determining the market risk using the value-at-risk approach. The findings of this study have implications for informationally market efficiency analysis, portfolio strategies and risk managements.

  14. Debates—Hypothesis testing in hydrology: Introduction

    Science.gov (United States)

    Blöschl, Günter

    2017-03-01

    This paper introduces the papers in the "Debates—Hypothesis testing in hydrology" series. The four articles in the series discuss whether and how the process of testing hypotheses leads to progress in hydrology. Repeated experiments with controlled boundary conditions are rarely feasible in hydrology. Research is therefore not easily aligned with the classical scientific method of testing hypotheses. Hypotheses in hydrology are often enshrined in computer models which are tested against observed data. Testability may be limited due to model complexity and data uncertainty. All four articles suggest that hypothesis testing has contributed to progress in hydrology and is needed in the future. However, the procedure is usually not as systematic as the philosophy of science suggests. A greater emphasis on a creative reasoning process on the basis of clues and explorative analyses is therefore needed.

  15. Eigenstate Thermalization Hypothesis and Quantum Thermodynamics

    Science.gov (United States)

    Olshanii, Maxim

    2009-03-01

    One of the open questions in quantum thermodynamics reads: how can linear quantum dynamics provide chaos necessary for thermalization of an isolated quantum system? To this end, we perform an ab initio numerical analysis of a system of hard-core bosons on a lattice and show [Marcos Rigol, Vanja Dunjko & Maxim Olshanii, Nature 452, 854 (2008)] that the above controversy can be resolved via the Eigenstate Thermalization Hypothesis suggested independently by Deutsch [J. M. Deutsch, Phys. Rev. A 43, 2046 (1991)] and Srednicki [M. Srednicki, Phys. Rev. E 50, 888 (1994)]. According to this hypothesis, in quantum systems thermalization happens in each individual eigenstate of the system separately, but it is hidden initially by coherences between them. In course of the time evolution the thermal properties become revealed through (linear) decoherence that needs not to be chaotic.

  16. Sea otter health: Challenging a pet hypothesis

    OpenAIRE

    Lafferty, Kevin D.

    2015-01-01

    A recent series of studies on tagged sea otters (Enhydra lutris nereis) challenges the hypothesis that sea otters are sentinels of a dirty ocean, in particular, that pet cats are the main source of exposure to Toxoplasma gondii in central California. Counter to expectations, sea otters from unpopulated stretches of coastline are less healthy and more exposed to parasites than city-associated otters. Ironically, now it seems that spillover from wildlife, not pets, dominates spatial patterns of...

  17. Sea otter health: Challenging a pet hypothesis

    Directory of Open Access Journals (Sweden)

    Kevin D. Lafferty

    2015-12-01

    Full Text Available A recent series of studies on tagged sea otters (Enhydra lutris nereis challenges the hypothesis that sea otters are sentinels of a dirty ocean, in particular, that pet cats are the main source of exposure to Toxoplasma gondii in central California. Counter to expectations, sea otters from unpopulated stretches of coastline are less healthy and more exposed to parasites than city-associated otters. Ironically, now it seems that spillover from wildlife, not pets, dominates spatial patterns of disease transmission.

  18. Sea otter health: Challenging a pet hypothesis.

    Science.gov (United States)

    Lafferty, Kevin D

    2015-12-01

    A recent series of studies on tagged sea otters (Enhydra lutris nereis) challenges the hypothesis that sea otters are sentinels of a dirty ocean, in particular, that pet cats are the main source of exposure to Toxoplasma gondii in central California. Counter to expectations, sea otters from unpopulated stretches of coastline are less healthy and more exposed to parasites than city-associated otters. Ironically, now it seems that spillover from wildlife, not pets, dominates spatial patterns of disease transmission.

  19. Sea otter health: challenging a pet hypothesis

    Science.gov (United States)

    Lafferty, Kevin D.

    2015-01-01

    A recent series of studies on tagged sea otters (Enhydra lutris nereis) challenges the hypothesis that sea otters are sentinels of a dirty ocean, in particular, that pet cats are the main source of exposure to Toxoplasma gondii in central California. Counter to expectations, sea otters from unpopulated stretches of coastline are less healthy and more exposed to parasites than city-associated otters. Ironically, now it seems that spillover from wildlife, not pets, dominates spatial patterns of disease transmission.

  20. Application of Sivasubramanian Kalimuthu Hypothesis to Triangles

    OpenAIRE

    M. Sivasubramanian

    2009-01-01

    Problem statement: The interior angles sum of a number of Euclidean triangles was transformed into quadratic equations. The analysis of those quadratic equations yielded the following proposition: There exists Euclidean triangle whose interior angle sum is a straight angle. Approach: In this study, the researchers introduced a new hypothesis for quadratic equations and derived an entirely new result. Results: The result of the study was controversial, but mathematically consistent. Conclusion...

  1. Kelvin on an old, celebrated hypothesis

    Science.gov (United States)

    Harrison, Edward

    1986-07-01

    Lord Kelvin in 1901 tested an ``old and celebrated hypothesis'' that if we could see far enough into space the whole sky would be occupied with stellar disks all of perhaps the same brightness as the Sun. Kelvin was the first to solve quantitatively and correctly the riddle of a dark night sky, a riddle that had been previously solved qualitatively by Edgar Allan Poe, and is now known as Olbers' paradox.

  2. Test of Taylor's Hypothesis with Distributed Temperature

    Science.gov (United States)

    Cheng, Y.; Gentine, P.; Sayde, C.; Tanner, E.; Ochsner, T. E.; Dong, J.

    2016-12-01

    Taylor's hypothesis[Taylor, 1938] assumes that mean wind speed carries the spatial pattern of turbulent motion past a fixed point in a "frozen" way, which has been widely used to relate streamwise wavenumber and angular frequency . Experiments[Fisher, 1964; Tong, 1996] have shown some deviation from Taylor's hypothesis at highly turbulent intensity flows and at high wavenumbers. However, the velocity or scalar measurements have always been fixed at a few spatial points rather than distributed in space. This experiment was designed for the first time to directly compare the time and spatial spectrum of temperature to test Taylor's hypothesis, measuring temperature with high resolution in both time and space by Distributed Temperature Sensing utilizing the attenuation difference of Raman scattering in the optic fiber at the MOISST site Oklahoma. The length of transact is 233 meters along the dominant wind direction. The temperature sampling distance is 0.127m and sampling time frequency is 1 Hz. The heights of the 4 fiber cables parallel to ground are 1m, 1.254m, 1.508m and 1.762m respectively. Also, eddy covariance instrument was set up near the Distributed Temperature Sensing as comparison for temperature data. The temperature spatial spectrum could be obtained with one fixed time point, while the temperature time spectrum could be obtained with one fixed spatial point in the middle of transact. The preliminary results would be presented in the AGU fall meeting. Reference Fisher, M. J., and Davies, P.O.A.L (1964), Correlation measurements in a non-frozen pattern of turbulence, Journal of fluid mechanics, 18(1), 97-116. Taylor, G. I. (1938), The spectrum of turbulence, Proceedings of the Royal Society of London A: Mathematical, Physical and Engineering Sciences, 164(919), 476-490. Tong, C. (1996), Taylor's Hypothesis and Two-point Coherence Measurements, Boundary-Layer Meteorology, 81(3), 399-410.

  3. Unaware Memory in Hypothesis Generation Tasks

    Science.gov (United States)

    1986-12-01

    distinguished two forms of memory : deliberate recollection of prior events versus the unaware influence of prior events on the performance of a later task...attempts to remember information. The findings reported here contribute in particular to our understanding of the memory processes involved in hypothesis... influenced by prior exposure to relevant events. Indeed, since the prior events themselves often cannot be consciously retrieved, this latter form of memory

  4. Wave-mean flow interaction and the baroclinic adjustment hypothesis

    International Nuclear Information System (INIS)

    MacKay, M.D.; Moore, G.W.K.

    1994-01-01

    It has been hypothesized that baroclinic waves interact with the zonally averaged flow in such a way as to eliminate the baroclinicity of the zone and thus the source of instability. In the context of quasigeostrophic theory this amounts to the elimination the pseudopotential vorticity gradient bar Q y via adjustments in the vertical shear, the static stability, or both. Strictly speaking baroclinic neutralization can occur simply by eliminating the temperature gradient at the ground. Gutowski, however, shows that the minimal (i.e., with respect to changes in the zonal available potential energy) adjustment required to stabilize the flow is that where bar Q y vanishes at the surface and in a finite layer above the surface. This is the baroclinic adjustment hypothesis

  5. Consumer health information seeking as hypothesis testing.

    Science.gov (United States)

    Keselman, Alla; Browne, Allen C; Kaufman, David R

    2008-01-01

    Despite the proliferation of consumer health sites, lay individuals often experience difficulty finding health information online. The present study attempts to understand users' information seeking difficulties by drawing on a hypothesis testing explanatory framework. It also addresses the role of user competencies and their interaction with internet resources. Twenty participants were interviewed about their understanding of a hypothetical scenario about a family member suffering from stable angina and then searched MedlinePlus consumer health information portal for information on the problem presented in the scenario. Participants' understanding of heart disease was analyzed via semantic analysis. Thematic coding was used to describe information seeking trajectories in terms of three key strategies: verification of the primary hypothesis, narrowing search within the general hypothesis area and bottom-up search. Compared to an expert model, participants' understanding of heart disease involved different key concepts, which were also differently grouped and defined. This understanding provided the framework for search-guiding hypotheses and results interpretation. Incorrect or imprecise domain knowledge led individuals to search for information on irrelevant sites, often seeking out data to confirm their incorrect initial hypotheses. Online search skills enhanced search efficiency, but did not eliminate these difficulties. Regardless of their web experience and general search skills, lay individuals may experience difficulty with health information searches. These difficulties may be related to formulating and evaluating hypotheses that are rooted in their domain knowledge. Informatics can provide support at the levels of health information portals, individual websites, and consumer education tools.

  6. A test of the orthographic recoding hypothesis

    Science.gov (United States)

    Gaygen, Daniel E.

    2003-04-01

    The Orthographic Recoding Hypothesis [D. E. Gaygen and P. A. Luce, Percept. Psychophys. 60, 465-483 (1998)] was tested. According to this hypothesis, listeners recognize spoken words heard for the first time by mapping them onto stored representations of the orthographic forms of the words. Listeners have a stable orthographic representation of words, but no phonological representation, when those words have been read frequently but never heard or spoken. Such may be the case for low frequency words such as jargon. Three experiments using visually and auditorily presented nonword stimuli tested this hypothesis. The first two experiments were explicit tests of memory (old-new tests) for words presented visually. In the first experiment, the recognition of auditorily presented nonwords was facilitated when they previously appeared on a visually presented list. The second experiment was similar, but included a concurrent articulation task during a visual word list presentation, thus preventing covert rehearsal of the nonwords. The results were similar to the first experiment. The third experiment was an indirect test of memory (auditory lexical decision task) for visually presented nonwords. Auditorily presented nonwords were identified as nonwords significantly more slowly if they had previously appeared on the visually presented list accompanied by a concurrent articulation task.

  7. Hypothesis Testing as an Act of Rationality

    Science.gov (United States)

    Nearing, Grey

    2017-04-01

    Statistical hypothesis testing is ad hoc in two ways. First, setting probabilistic rejection criteria is, as Neyman (1957) put it, an act of will rather than an act of rationality. Second, physical theories like conservation laws do not inherently admit probabilistic predictions, and so we must use what are called epistemic bridge principles to connect model predictions with the actual methods of hypothesis testing. In practice, these bridge principles are likelihood functions, error functions, or performance metrics. I propose that the reason we are faced with these problems is because we have historically failed to account for a fundamental component of basic logic - namely the portion of logic that explains how epistemic states evolve in the presence of empirical data. This component of Cox' (1946) calculitic logic is called information theory (Knuth, 2005), and adding information theory our hypothetico-deductive account of science yields straightforward solutions to both of the above problems. This also yields a straightforward method for dealing with Popper's (1963) problem of verisimilitude by facilitating a quantitative approach to measuring process isomorphism. In practice, this involves data assimilation. Finally, information theory allows us to reliably bound measures of epistemic uncertainty, thereby avoiding the problem of Bayesian incoherency under misspecified priors (Grünwald, 2006). I therefore propose solutions to four of the fundamental problems inherent in both hypothetico-deductive and/or Bayesian hypothesis testing. - Neyman (1957) Inductive Behavior as a Basic Concept of Philosophy of Science. - Cox (1946) Probability, Frequency and Reasonable Expectation. - Knuth (2005) Lattice Duality: The Origin of Probability and Entropy. - Grünwald (2006). Bayesian Inconsistency under Misspecification. - Popper (1963) Conjectures and Refutations: The Growth of Scientific Knowledge.

  8. Statistical hypothesis testing with SAS and R

    CERN Document Server

    Taeger, Dirk

    2014-01-01

    A comprehensive guide to statistical hypothesis testing with examples in SAS and R When analyzing datasets the following questions often arise:Is there a short hand procedure for a statistical test available in SAS or R?If so, how do I use it?If not, how do I program the test myself? This book answers these questions and provides an overview of the most commonstatistical test problems in a comprehensive way, making it easy to find and performan appropriate statistical test. A general summary of statistical test theory is presented, along with a basicdescription for each test, including the

  9. The conscious access hypothesis: Explaining the consciousness.

    Science.gov (United States)

    Prakash, Ravi

    2008-01-01

    The phenomenon of conscious awareness or consciousness is complicated but fascinating. Although this concept has intrigued the mankind since antiquity, exploration of consciousness from scientific perspectives is not very old. Among myriad of theories regarding nature, functions and mechanism of consciousness, off late, cognitive theories have received wider acceptance. One of the most exciting hypotheses in recent times has been the "conscious access hypotheses" based on the "global workspace model of consciousness". It underscores an important property of consciousness, the global access of information in cerebral cortex. Present article reviews the "conscious access hypothesis" in terms of its theoretical underpinnings as well as experimental supports it has received.

  10. Confluence Model or Resource Dilution Hypothesis?

    DEFF Research Database (Denmark)

    Jæger, Mads

    Studies on family background often explain the negative effect of sibship size on educational attainment by one of two theories: the Confluence Model (CM) or the Resource Dilution Hypothesis (RDH). However, as both theories – for substantively different reasons – predict that sibship size should...... to identify a unique RDH effect on educational attainment. Using sibling data from the Wisconsin Longitudinal Study (WLS) and a random effect Instrumental Variable model, I find that in addition to having a negative effect on cognitive ability, sibship size also has a strong negative effect on educational...

  11. Set theory and the continuum hypothesis

    CERN Document Server

    Cohen, Paul J

    2008-01-01

    This exploration of a notorious mathematical problem is the work of the man who discovered the solution. The independence of the continuum hypothesis is the focus of this study by Paul J. Cohen. It presents not only an accessible technical explanation of the author's landmark proof but also a fine introduction to mathematical logic. An emeritus professor of mathematics at Stanford University, Dr. Cohen won two of the most prestigious awards in mathematics: in 1964, he was awarded the American Mathematical Society's Bôcher Prize for analysis; and in 1966, he received the Fields Medal for Logic.

  12. A HYPOTHESIS FOR THE COLOR BIMODALITY OF JUPITER TROJANS

    International Nuclear Information System (INIS)

    Wong, Ian; Brown, Michael E.

    2016-01-01

    One of the most enigmatic and hitherto unexplained properties of Jupiter Trojans is their bimodal color distribution. This bimodality is indicative of two sub-populations within the Trojans, which have distinct size distributions. In this paper, we present a simple, plausible hypothesis for the origin and evolution of the two Trojan color sub-populations. In the framework of dynamical instability models of early solar system evolution, which suggest a common primordial progenitor population for both Trojans and Kuiper Belt objects, we use observational constraints to assert that the color bimodalities evident in both minor body populations developed within the primordial population prior to the onset of instability. We show that, beginning with an initial composition of rock and ices, location-dependent volatile loss through sublimation in this primordial population could have led to sharp changes in the surface composition with heliocentric distance. We propose that the depletion or retention of H 2 S ice on the surface of these objects was the key factor in creating an initial color bimodality. Objects that retained H 2 S on their surfaces developed characteristically redder colors upon irradiation than those that did not. After the bodies from the primordial population were scattered and emplaced into their current positions, they preserved this primordial color bimodality to the present day. We explore predictions of the volatile loss model—in particular, the effect of collisions within the Trojan population on the size distributions of the two sub-populations—and propose further experimental and observational tests of our hypothesis.

  13. A HYPOTHESIS FOR THE COLOR BIMODALITY OF JUPITER TROJANS

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Ian; Brown, Michael E., E-mail: iwong@caltech.edu [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States)

    2016-10-01

    One of the most enigmatic and hitherto unexplained properties of Jupiter Trojans is their bimodal color distribution. This bimodality is indicative of two sub-populations within the Trojans, which have distinct size distributions. In this paper, we present a simple, plausible hypothesis for the origin and evolution of the two Trojan color sub-populations. In the framework of dynamical instability models of early solar system evolution, which suggest a common primordial progenitor population for both Trojans and Kuiper Belt objects, we use observational constraints to assert that the color bimodalities evident in both minor body populations developed within the primordial population prior to the onset of instability. We show that, beginning with an initial composition of rock and ices, location-dependent volatile loss through sublimation in this primordial population could have led to sharp changes in the surface composition with heliocentric distance. We propose that the depletion or retention of H{sub 2}S ice on the surface of these objects was the key factor in creating an initial color bimodality. Objects that retained H{sub 2}S on their surfaces developed characteristically redder colors upon irradiation than those that did not. After the bodies from the primordial population were scattered and emplaced into their current positions, they preserved this primordial color bimodality to the present day. We explore predictions of the volatile loss model—in particular, the effect of collisions within the Trojan population on the size distributions of the two sub-populations—and propose further experimental and observational tests of our hypothesis.

  14. Roots and Route of the Artification Hypothesis

    Directory of Open Access Journals (Sweden)

    Ellen Dissanayake

    2017-08-01

    Full Text Available Over four decades, my ideas about the arts in human evolution have themselves evolved, from an original notion of art as a human behaviour of “making special” to a full-fledged hypothesis of artification. A summary of the gradual developmental path (or route of the hypothesis, based on ethological principles and concepts, is given, and an argument presented in which artification is described as an exaptation whose roots lie in adaptive features of ancestral mother–infant interaction that contributed to infant survival and maternal reproductive success. I show how the interaction displays features of a ritualised behavior whose operations (formalization, repetition, exaggeration, and elaboration can be regarded as characteristic elements of human ritual ceremonies as well as of art (including song, dance, performance, literary language, altered surroundings, and other examples of making ordinary sounds, movement, language, environments, objects, and bodies extraordinary. Participation in these behaviours in ritual practices served adaptive ends in early Homo by coordinating brain and body states, and thereby emotionally bonding members of a group in common cause as well as reducing existential anxiety in individuals. A final section situates artification within contemporary philosophical and popular ideas of art, claiming that artifying is not a synonym for or definition of art but foundational to any evolutionary discussion of artistic/aesthetic behaviour.

  15. The alliance hypothesis for human friendship.

    Science.gov (United States)

    DeScioli, Peter; Kurzban, Robert

    2009-06-03

    Exploration of the cognitive systems underlying human friendship will be advanced by identifying the evolved functions these systems perform. Here we propose that human friendship is caused, in part, by cognitive mechanisms designed to assemble support groups for potential conflicts. We use game theory to identify computations about friends that can increase performance in multi-agent conflicts. This analysis suggests that people would benefit from: 1) ranking friends, 2) hiding friend-ranking, and 3) ranking friends according to their own position in partners' rankings. These possible tactics motivate the hypotheses that people possess egocentric and allocentric representations of the social world, that people are motivated to conceal this information, and that egocentric friend-ranking is determined by allocentric representations of partners' friend-rankings (more than others' traits). We report results from three studies that confirm predictions derived from the alliance hypothesis. Our main empirical finding, replicated in three studies, was that people's rankings of their ten closest friends were predicted by their own perceived rank among their partners' other friends. This relationship remained strong after controlling for a variety of factors such as perceived similarity, familiarity, and benefits. Our results suggest that the alliance hypothesis merits further attention as a candidate explanation for human friendship.

  16. Revisiting the genomic hypomethylation hypothesis of aging.

    Science.gov (United States)

    Unnikrishnan, Archana; Hadad, Niran; Masser, Dustin R; Jackson, Jordan; Freeman, Willard M; Richardson, Arlan

    2018-01-24

    The genomic hypomethylation hypothesis of aging proposes that an overall decrease in global DNA methylation occurs with age, and it has been argued that the decrease in global DNA methylation could be an important factor in aging, resulting in the relaxation of gene expression regulation and abnormal gene expression. Since it was initially observed that DNA methylation decreased with age in 1974, 16 articles have been published describing the effect of age on global DNA methylation in various tissues from rodents and humans. We critically reviewed the publications on the effect of age on DNA methylation and the expression of the enzymes involved in DNA methylation to evaluate the validity of the hypomethylation hypothesis of aging. On the basis of the current scientific literature, we conclude that a decrease in the global methylation of the genome occurs in most if not all tissues/cells as an animal ages. However, age-related changes in DNA methylation in specific regions or at specific sites in the genome occur even though the global DNA methylation does not change. © 2018 The Authors. Annals of the New York Academy of Sciences published by Wiley Periodicals, Inc. on behalf of New York Academy of Sciences.

  17. Hypothesis-driven physical examination curriculum.

    Science.gov (United States)

    Allen, Sharon; Olson, Andrew; Menk, Jeremiah; Nixon, James

    2017-12-01

    Medical students traditionally learn physical examination skills as a rote list of manoeuvres. Alternatives like hypothesis-driven physical examination (HDPE) may promote students' understanding of the contribution of physical examination to diagnostic reasoning. We sought to determine whether first-year medical students can effectively learn to perform a physical examination using an HDPE approach, and then tailor the examination to specific clinical scenarios. Medical students traditionally learn physical examination skills as a rote list of manoeuvres CONTEXT: First-year medical students at the University of Minnesota were taught both traditional and HDPE approaches during a required 17-week clinical skills course in their first semester. The end-of-course evaluation assessed HDPE skills: students were assigned one of two cardiopulmonary cases. Each case included two diagnostic hypotheses. During an interaction with a standardised patient, students were asked to select physical examination manoeuvres in order to make a final diagnosis. Items were weighted and selection order was recorded. First-year students with minimal pathophysiology performed well. All students selected the correct diagnosis. Importantly, students varied the order when selecting examination manoeuvres depending on the diagnoses under consideration, demonstrating early clinical decision-making skills. An early introduction to HDPE may reinforce physical examination skills for hypothesis generation and testing, and can foster early clinical decision-making skills. This has important implications for further research in physical examination instruction. © 2016 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

  18. The Debt Overhang Hypothesis: Evidence from Pakistan

    Directory of Open Access Journals (Sweden)

    Shah Muhammad Imran

    2016-04-01

    Full Text Available This study investigates the debt overhang hypothesis for Pakistan in the period 1960-2007. The study examines empirically the dynamic behaviour of GDP, debt services, the employed labour force and investment using the time series concepts of unit roots, cointegration, error correlation and causality. Our findings suggest that debt-servicing has a negative impact on the productivity of both labour and capital, and that in turn has adversely affected economic growth. By severely constraining the ability of the country to service debt, this lends support to the debt-overhang hypothesis in Pakistan. The long run relation between debt services and economic growth implies that future increases in output will drain away in form of high debt service payments to lender country as external debt acts like a tax on output. More specifically, foreign creditors will benefit more from the rise in productivity than will domestic producers and labour. This suggests that domestic labour and capital are the ultimate losers from this heavy debt burden.

  19. Gaussian Hypothesis Testing and Quantum Illumination.

    Science.gov (United States)

    Wilde, Mark M; Tomamichel, Marco; Lloyd, Seth; Berta, Mario

    2017-09-22

    Quantum hypothesis testing is one of the most basic tasks in quantum information theory and has fundamental links with quantum communication and estimation theory. In this paper, we establish a formula that characterizes the decay rate of the minimal type-II error probability in a quantum hypothesis test of two Gaussian states given a fixed constraint on the type-I error probability. This formula is a direct function of the mean vectors and covariance matrices of the quantum Gaussian states in question. We give an application to quantum illumination, which is the task of determining whether there is a low-reflectivity object embedded in a target region with a bright thermal-noise bath. For the asymmetric-error setting, we find that a quantum illumination transmitter can achieve an error probability exponent stronger than a coherent-state transmitter of the same mean photon number, and furthermore, that it requires far fewer trials to do so. This occurs when the background thermal noise is either low or bright, which means that a quantum advantage is even easier to witness than in the symmetric-error setting because it occurs for a larger range of parameters. Going forward from here, we expect our formula to have applications in settings well beyond those considered in this paper, especially to quantum communication tasks involving quantum Gaussian channels.

  20. A default Bayesian hypothesis test for mediation.

    Science.gov (United States)

    Nuijten, Michèle B; Wetzels, Ruud; Matzke, Dora; Dolan, Conor V; Wagenmakers, Eric-Jan

    2015-03-01

    In order to quantify the relationship between multiple variables, researchers often carry out a mediation analysis. In such an analysis, a mediator (e.g., knowledge of a healthy diet) transmits the effect from an independent variable (e.g., classroom instruction on a healthy diet) to a dependent variable (e.g., consumption of fruits and vegetables). Almost all mediation analyses in psychology use frequentist estimation and hypothesis-testing techniques. A recent exception is Yuan and MacKinnon (Psychological Methods, 14, 301-322, 2009), who outlined a Bayesian parameter estimation procedure for mediation analysis. Here we complete the Bayesian alternative to frequentist mediation analysis by specifying a default Bayesian hypothesis test based on the Jeffreys-Zellner-Siow approach. We further extend this default Bayesian test by allowing a comparison to directional or one-sided alternatives, using Markov chain Monte Carlo techniques implemented in JAGS. All Bayesian tests are implemented in the R package BayesMed (Nuijten, Wetzels, Matzke, Dolan, & Wagenmakers, 2014).

  1. Investigating deaf students' knowledge of Persian syntax: further evidence for a critical period hypothesis.

    Science.gov (United States)

    Gheitury, Amer; Ashraf, Vida; Hashemi, Reza

    2014-06-01

    The present study aims to investigate syntactic deficits in 13 Iranian deaf students aged between 17 and 21 years. Four tests in the form of sentence-recognition and sentence-completion were administered to examine their knowledge of verb inflection, derivational morphology, word order, and prepositions. A between-category analysis of errors indicated a significant dissociation between categories, most notably between verb inflection and derivational morphology and between word order as the category with fewest errors and the three others. On theoretical grounds, the fact that subjects have not acquired much syntax even after years of learning seemed to strengthen the significance of acquiring syntax and morphology in the early years.

  2. Learning-Related Changes in Adolescents' Neural Networks during Hypothesis-Generating and Hypothesis-Understanding Training

    Science.gov (United States)

    Lee, Jun-Ki; Kwon, Yongju

    2012-01-01

    Fourteen science high school students participated in this study, which investigated neural-network plasticity associated with hypothesis-generating and hypothesis-understanding in learning. The students were divided into two groups and participated in either hypothesis-generating or hypothesis-understanding type learning programs, which were…

  3. The Criticality Hypothesis in Neural Systems

    Science.gov (United States)

    Karimipanah, Yahya

    There is mounting evidence that neural networks of the cerebral cortex exhibit scale invariant dynamics. At the larger scale, fMRI recordings have shown evidence for spatiotemporal long range correlations. On the other hand, at the smaller scales this scale invariance is marked by the power law distribution of the size and duration of spontaneous bursts of activity, which are referred as neuronal avalanches. The existence of such avalanches has been confirmed by several studies in vitro and in vivo, among different species and across multiple scales, from spatial scale of MEG and EEG down to single cell resolution. This prevalent scale free nature of cortical activity suggests the hypothesis that the cortex resides at a critical state between two phases of order (short-lasting activity) and disorder (long-lasting activity). In addition, it has been shown, both theoretically and experimentally, that being at criticality brings about certain functional advantages for information processing. However, despite the plenty of evidence and plausibility of the neural criticality hypothesis, still very little is known on how the brain may leverage such criticality to facilitate neural coding. Moreover, the emergent functions that may arise from critical dynamics is poorly understood. In the first part of this thesis, we review several pieces of evidence for the neural criticality hypothesis at different scales, as well as some of the most popular theories of self-organized criticality (SOC). Thereafter, we will focus on the most prominent evidence from small scales, namely neuronal avalanches. We will explore the effect of adaptation and how it can maintain scale free dynamics even at the presence of external stimuli. Using calcium imaging we also experimentally demonstrate the existence of scale free activity at the cellular resolution in vivo. Moreover, by exploring the subsampling issue in neural data, we will find some fundamental constraints of the conventional methods

  4. A novel hypothesis splitting method implementation for multi-hypothesis filters

    DEFF Research Database (Denmark)

    Bayramoglu, Enis; Ravn, Ole; Andersen, Nils Axel

    2013-01-01

    The paper presents a multi-hypothesis filter library featuring a novel method for splitting Gaussians into ones with smaller variances. The library is written in C++ for high performance and the source code is open and free1. The multi-hypothesis filters commonly approximate the distribution...... transformations better, if the covariances of the individual hypotheses are sufficiently small. We propose a look-up table based method to calculate a set of Gaussian hypotheses approximating a wider Gaussian in order to improve the filter approximation. Python bindings for the library are also provided for fast...

  5. Alternatives to the linear risk hypothesis

    International Nuclear Information System (INIS)

    Craig, A.G.

    1976-01-01

    A theoretical argument is presented which suggests that in using the linear hypothesis for all values of LET the low dose risk is overestimated for low LET but that it is underestimated for very high LET. The argument is based upon the idea that cell lesions which do not lead to cell death may in fact lead to a malignant cell. Expressions for the Surviving Fraction and the Cancer Risk based on this argument are given. An advantage of this very general approach is that is expresses cell survival and cancer risk entirely in terms of the cell lesions and avoids the rather contentious argument as to how the average number of lesions should be related to the dose. (U.K.)

  6. Novae, supernovae, and the island universe hypothesis

    International Nuclear Information System (INIS)

    Van Den Bergh, S.

    1988-01-01

    Arguments in Curtis's (1917) paper related to the island universe hypothesis and the existence of novae in spiral nebulae are considered. It is noted that the maximum magnitude versus rate-of-decline relation for novae may be the best tool presently available for the calibration of the extragalactic distance scale. Light curve observations of six novae are used to determine a distance of 18.6 + or - 3.5 MPc to the Virgo cluster. Results suggest that Type Ia supernovae cannot easily be used as standard candles, and that Type II supernovae are unsuitable as distance indicators. Factors other than precursor mass are probably responsible for determining the ultimate fate of evolving stars. 83 references

  7. Multi-hypothesis modelling of snowmelt

    Science.gov (United States)

    Essery, R.

    2017-12-01

    Modules to predict the melt of snow on the ground are essential components of hydrological and climatological models. Energy to melt snow can come from shortwave or longwave radiation fluxes, turbulent heat fluxes from the atmosphere, conducted heat fluxes from the ground or advected heat in rain falling on snow. Multiple competing hypotheses (parametrizations) for these fluxes and how they are connected to model state variables are in current use. The multiple sources of energy and limited data to constrain them lead to a great deal of equifinality and difficulties in understanding model behaviour. This presentation will discuss how a multi-hypothesis snow model can be used to understand the complementary, competing and confounding influences of model structural choices, parameter uncertainty and input data errors on simulations of snowmelt.

  8. Extra dimensions hypothesis in high energy physics

    Directory of Open Access Journals (Sweden)

    Volobuev Igor

    2017-01-01

    Full Text Available We discuss the history of the extra dimensions hypothesis and the physics and phenomenology of models with large extra dimensions with an emphasis on the Randall- Sundrum (RS model with two branes. We argue that the Standard Model extension based on the RS model with two branes is phenomenologically acceptable only if the inter-brane distance is stabilized. Within such an extension of the Standard Model, we study the influence of the infinite Kaluza-Klein (KK towers of the bulk fields on collider processes. In particular, we discuss the modification of the scalar sector of the theory, the Higgs-radion mixing due to the coupling of the Higgs boson to the radion and its KK tower, and the experimental restrictions on the mass of the radion-dominated states.

  9. Large numbers hypothesis. II - Electromagnetic radiation

    Science.gov (United States)

    Adams, P. J.

    1983-01-01

    This paper develops the theory of electromagnetic radiation in the units covariant formalism incorporating Dirac's large numbers hypothesis (LNH). A direct field-to-particle technique is used to obtain the photon propagation equation which explicitly involves the photon replication rate. This replication rate is fixed uniquely by requiring that the form of a free-photon distribution function be preserved, as required by the 2.7 K cosmic radiation. One finds that with this particular photon replication rate the units covariant formalism developed in Paper I actually predicts that the ratio of photon number to proton number in the universe varies as t to the 1/4, precisely in accord with LNH. The cosmological red-shift law is also derived and it is shown to differ considerably from the standard form of (nu)(R) - const.

  10. The Stress Acceleration Hypothesis of Nightmares

    Directory of Open Access Journals (Sweden)

    Tore Nielsen

    2017-06-01

    Full Text Available Adverse childhood experiences can deleteriously affect future physical and mental health, increasing risk for many illnesses, including psychiatric problems, sleep disorders, and, according to the present hypothesis, idiopathic nightmares. Much like post-traumatic nightmares, which are triggered by trauma and lead to recurrent emotional dreaming about the trauma, idiopathic nightmares are hypothesized to originate in early adverse experiences that lead in later life to the expression of early memories and emotions in dream content. Accordingly, the objectives of this paper are to (1 review existing literature on sleep, dreaming and nightmares in relation to early adverse experiences, drawing upon both empirical studies of dreaming and nightmares and books and chapters by recognized nightmare experts and (2 propose a new approach to explaining nightmares that is based upon the Stress Acceleration Hypothesis of mental illness. The latter stipulates that susceptibility to mental illness is increased by adversity occurring during a developmentally sensitive window for emotional maturation—the infantile amnesia period—that ends around age 3½. Early adversity accelerates the neural and behavioral maturation of emotional systems governing the expression, learning, and extinction of fear memories and may afford short-term adaptive value. But it also engenders long-term dysfunctional consequences including an increased risk for nightmares. Two mechanisms are proposed: (1 disruption of infantile amnesia allows normally forgotten early childhood memories to influence later emotions, cognitions and behavior, including the common expression of threats in nightmares; (2 alterations of normal emotion regulation processes of both waking and sleep lead to increased fear sensitivity and less effective fear extinction. These changes influence an affect network previously hypothesized to regulate fear extinction during REM sleep, disruption of which leads to

  11. On the immunostimulatory hypothesis of cancer

    Directory of Open Access Journals (Sweden)

    Juan Bruzzo

    2011-12-01

    Full Text Available There is a rather generalized belief that the worst possible outcome for the application of immunological therapies against cancer is a null effect on tumor growth. However, a significant body of evidence summarized in the immunostimulatory hypothesis of cancer suggests that, upon certain circumstances, the growth of incipient and established tumors can be accelerated rather than inhibited by the immune response supposedly mounted to limit tumor growth. In order to provide more compelling evidence of this proposition, we have explored the growth behavior characteristics of twelve murine tumors -most of them of spontaneous origin- arisen in the colony of our laboratory, in putatively immunized and control mice. Using classical immunization procedures, 8 out of 12 tumors were actually stimulated in "immunized" mice while the remaining 4 were neither inhibited nor stimulated. Further, even these apparently non-antigenic tumors could reveal some antigenicity if more stringent than classical immunization procedures were used. This possibility was suggested by the results obtained with one of these four apparently non-antigenic tumors: the LB lymphoma. In effect, upon these stringent immunization pretreatments, LB was slightly inhibited or stimulated, depending on the titer of the immune reaction mounted against the tumor, with higher titers rendering inhibition and lower titers rendering tumor stimulation. All the above results are consistent with the immunostimulatory hypothesis that entails the important therapeutic implications -contrary to the orthodoxy- that, anti-tumor vaccines may run a real risk of doing harm if the vaccine-induced immunity is too weak to move the reaction into the inhibitory part of the immune response curve and that, a slight and prolonged immunodepression -rather than an immunostimulation- might interfere with the progression of some tumors and thus be an aid to cytotoxic therapies.

  12. The Stress Acceleration Hypothesis of Nightmares

    Science.gov (United States)

    Nielsen, Tore

    2017-01-01

    Adverse childhood experiences can deleteriously affect future physical and mental health, increasing risk for many illnesses, including psychiatric problems, sleep disorders, and, according to the present hypothesis, idiopathic nightmares. Much like post-traumatic nightmares, which are triggered by trauma and lead to recurrent emotional dreaming about the trauma, idiopathic nightmares are hypothesized to originate in early adverse experiences that lead in later life to the expression of early memories and emotions in dream content. Accordingly, the objectives of this paper are to (1) review existing literature on sleep, dreaming and nightmares in relation to early adverse experiences, drawing upon both empirical studies of dreaming and nightmares and books and chapters by recognized nightmare experts and (2) propose a new approach to explaining nightmares that is based upon the Stress Acceleration Hypothesis of mental illness. The latter stipulates that susceptibility to mental illness is increased by adversity occurring during a developmentally sensitive window for emotional maturation—the infantile amnesia period—that ends around age 3½. Early adversity accelerates the neural and behavioral maturation of emotional systems governing the expression, learning, and extinction of fear memories and may afford short-term adaptive value. But it also engenders long-term dysfunctional consequences including an increased risk for nightmares. Two mechanisms are proposed: (1) disruption of infantile amnesia allows normally forgotten early childhood memories to influence later emotions, cognitions and behavior, including the common expression of threats in nightmares; (2) alterations of normal emotion regulation processes of both waking and sleep lead to increased fear sensitivity and less effective fear extinction. These changes influence an affect network previously hypothesized to regulate fear extinction during REM sleep, disruption of which leads to nightmares. This

  13. The Nebular Hypothesis - A False Paradigm Misleading Scientists

    Science.gov (United States)

    Myers, L. S.

    2005-05-01

    Science has reached a turning point in history after being misled for 250 years by Immanuel Kant's nebular hypothesis, the most fundamental assumption in science. The nebular hypothesis assumes all nine planets were created 4.5 billion years ago (Ga) as molten bodies that cooled with the same size and chemical composition they have today. Reevaluation of the nebular hypothesis proves it has been wrong since its inception. The proof has lain in plain sight for centuries-coal beds that could not have existed at the assumed time of creation because they formed on Earth's surface after creation of the planet when forests and swamps were exposed to solar energy. The coal beds were subsequently buried under overburden accreted in later millennia, steadily increasing Earth's mass and diameter. The coal beds and layers of overburden are proof Earth was not created 4.5 Ga but is growing and expanding by accretion of extraterrestrial mass and core expansion-a process termed "Accreation" (creation by accretion). Each process accelerates over time, but internal expansion exceeds the rate of external accretion. Because the nebular hypothesis is erroneous researchers assumed Earth's diameter never changes, and, faced with the possibility the Earth might be expanding after the Atlantic basin was discovered to be widening, this assumption led to the unworkable concept of subduction to maintain a constant diameter Earth. Subduction will prove to be one of the greatest errors in the history of science. Nullification of the nebular hypothesis also nullifies subduction and rejuvenates Carey's earth expansion theory. Accreation provides Carey's missing energy source and mechanism of expansion. Expansion is proved by morphologic evidence today's continents were once a single planetary landmass on a smaller Earth when today's oceans, covering 70% of the planet, did not exist 200-250 Ma. Despite hundreds of tons of meteorites and dust known to accrete daily, its cumulative effect has been

  14. A Cross-linguistic Perspective on Questions in German and French Adult Second Language Acquisition

    OpenAIRE

    Matthias Bonnesen; Solveig Chilla

    2012-01-01

    Several studies have been conducted to try and understand and explain the morphological and syntactic aspects of adult second language acquisition (SLA). Two prominent hypotheses that have been put forward concerning late L2 speakers' knowledge of inflectional morphology and of related functional categories and their feature values are the Impaired Representation Hypothesis (IRH) and the Missing Surface Inflection Hypothesis (MSIH).The cross-linguistic comparison of the acquisition of questio...

  15. The Matter-Gravity Entanglement Hypothesis

    Science.gov (United States)

    Kay, Bernard S.

    2018-03-01

    I outline some of my work and results (some dating back to 1998, some more recent) on my matter-gravity entanglement hypothesis, according to which the entropy of a closed quantum gravitational system is equal to the system's matter-gravity entanglement entropy. The main arguments presented are: (1) that this hypothesis is capable of resolving what I call the second-law puzzle, i.e. the puzzle as to how the entropy increase of a closed system can be reconciled with the asssumption of unitary time-evolution; (2) that the black hole information loss puzzle may be regarded as a special case of this second law puzzle and that therefore the same resolution applies to it; (3) that the black hole thermal atmosphere puzzle (which I recall) can be resolved by adopting a radically different-from-usual description of quantum black hole equilibrium states, according to which they are total pure states, entangled between matter and gravity in such a way that the partial states of matter and gravity are each approximately thermal equilibrium states (at the Hawking temperature); (4) that the Susskind-Horowitz-Polchinski string-theoretic understanding of black hole entropy as the logarithm of the degeneracy of a long string (which is the weak string coupling limit of a black hole) cannot be quite correct but should be replaced by a modified understanding according to which it is the entanglement entropy between a long string and its stringy atmosphere, when in a total pure equilibrium state in a suitable box, which (in line with (3)) goes over, at strong-coupling, to a black hole in equilibrium with its thermal atmosphere. The modified understanding in (4) is based on a general result, which I also describe, which concerns the likely state of a quantum system when it is weakly coupled to an energy-bath and the total state is a random pure state with a given energy. This result generalizes Goldstein et al.'s `canonical typicality' result to systems which are not necessarily small.

  16. Learning and sleep: the sequential hypothesis.

    Science.gov (United States)

    Ambrosini, M V.; Giuditta, A

    2001-12-01

    During the last 30 years, paradoxical sleep (PS) has been generally considered as the only type of sleep involved in memory processing, mainly for the consistent increase of PS episodes in laboratory animals learning a relatively complex task, and for the retention deficits induced by post-training PS deprivation. The vicissitudes of this idea, examined in detail by several laboratories, have been critically presented in a number of review articles However, according to a more comprehensive unitary proposal (the sequential hypothesis), memory processing during sleep does require the initial participation of slow-wave sleep (SS) in addition to the subsequent involvement of PS. The evidence supporting this hypothesis, largely derived from experiments concerning rats trained for a two-way active avoidance task, is reviewed here in some detail. Recent studies of human sleep are in full agreement with this view. In the rat, the main effect of learning on post-training SS consists in the selective increment in the average duration of SS episodes initiating different types of sleep sequences. Notably, following training for a two-way active avoidance task, the occurrence of this effect in sleep sequences including transition sleep (TS), such as SS-->TS-->W and SS-->TS-->PS, appears related to the processing of memories of the novel avoidance response. Conversely, the occurrence of the same effect in sleep sequences lacking TS may reflect the processing of memories of innate responses (escapes and freezings). Memories of innate and novel responses are assumed to engage in a dynamic competitive interaction to attain control of waking behaviour. Interestingly, in baseline sleep, variables of SS-->TS-->W and SS-->TS-->PS sequences, such as the average duration of SS, TS, and PS episodes, have proved to be good indices of the capacity to learn, as shown by their strong correlations with the number of avoidances scored by rats the following day. Comparable correlations have not

  17. Evolutionary hypothesis for Chiari type I malformation.

    Science.gov (United States)

    Fernandes, Yvens Barbosa; Ramina, Ricardo; Campos-Herrera, Cynthia Resende; Borges, Guilherme

    2013-10-01

    Chiari I malformation (CM-I) is classically defined as a cerebellar tonsillar herniation (≥5 mm) through the foramen magnum. A decreased posterior fossa volume, mainly due to basioccipital hypoplasia and sometimes platybasia, leads to posterior fossa overcrowding and consequently cerebellar herniation. Regardless of radiological findings, embryological genetic hypothesis or any other postulations, the real cause behind this malformation is yet not well-elucidated and remains largely unknown. The aim of this paper is to approach CM-I under a broader and new perspective, conjoining anthropology, genetics and neurosurgery, with special focus on the substantial changes that have occurred in the posterior cranial base through human evolution. Important evolutionary allometric changes occurred during brain expansion and genetics studies of human evolution demonstrated an unexpected high rate of gene flow interchange and possibly interbreeding during this process. Based upon this review we hypothesize that CM-I may be the result of an evolutionary anthropological imprint, caused by evolving species populations that eventually met each other and mingled in the last 1.7 million years. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Environmental Kuznets Curve Hypothesis. A Survey

    International Nuclear Information System (INIS)

    Dinda, Soumyananda

    2004-01-01

    The Environmental Kuznets Curve (EKC) hypothesis postulates an inverted-U-shaped relationship between different pollutants and per capita income, i.e., environmental pressure increases up to a certain level as income goes up; after that, it decreases. An EKC actually reveals how a technically specified measurement of environmental quality changes as the fortunes of a country change. A sizeable literature on EKC has grown in recent period. The common point of all the studies is the assertion that the environmental quality deteriorates at the early stages of economic development/growth and subsequently improves at the later stages. In other words, environmental pressure increases faster than income at early stages of development and slows down relative to GDP growth at higher income levels. This paper reviews some theoretical developments and empirical studies dealing with EKC phenomenon. Possible explanations for this EKC are seen in (1) the progress of economic development, from clean agrarian economy to polluting industrial economy to clean service economy; (2) tendency of people with higher income having higher preference for environmental quality, etc. Evidence of the existence of the EKC has been questioned from several corners. Only some air quality indicators, especially local pollutants, show the evidence of an EKC. However, an EKC is empirically observed, till there is no agreement in the literature on the income level at which environmental degradation starts declining. This paper provides an overview of the EKC literature, background history, conceptual insights, policy and the conceptual and methodological critique

  19. Evidence for the spotting hypothesis in gymnasts.

    Science.gov (United States)

    Heinen, Thomas

    2011-04-01

    The goal of this study was to investigate the visual spotting hypothesis in 10 experts and 10 apprentices as they perform back aerial somersaults from a standing position with no preparatory jumps (short flight duration condition) and after some preparatory jumps with a flight time of 1s (long flight duration condition). Differences in gaze behavior and kinematics were expected between experts and apprentices and between experimental conditions. Gaze behavior was measured using a portable and wireless eye-tracking system in combination with a movement-analysis system. Experts exhibited a smaller landing deviation from the middle of the trampoline bed than apprentices. Experts showed higher fixation ratios during the take-off and flight phase. Experts exhibited no blinks in any of the somersaults in both conditions, whereas apprentices showed significant blink ratios in both experimental conditions. The findings suggest that gymnasts can use visual spotting during the back aerial somersault, even when the time of flight is delimited. We conclude that knowledge about gaze-movement relationships may help coaches develop specific training programs in the learning process of the back aerial somersault.

  20. [Hypothesis of "sinew-meridian system"].

    Science.gov (United States)

    Liu, Nongyu

    2017-01-12

    The author provides the hypothesis on the "sinew-meridian system" in terms of the physiology, pathology, diagnosis and treatment of meridians and sinew-meridians. Meridians are nourished with blood and sinew-meridians are softened with yang qi . Meridians are circulated in linear form and sinew-meridians are distributed in centripetal state. Meridians are communicated externally and internally and sinew-meridians are connected with tendons and bones. Meridians pertain to zangfu organs and sinew-meridians stabilize zangfu organs. Meridians nourish five sensory organs and sinew-meridians moisten nine orifices. Meridians are characterized as nourishment and sinew-meridians as solidity. Meridians emphasize the conditions of either deficiency or excess, and sinew-meridians as either cold or heat. The meridian disorder is located deeply and of complex and sinew-meridian's is located superficially and of simplicity. The meridian disorder is difficult to treat and with poor therapeutic effect and the sinew-meridian disorder is easy to treat and with rapid therapeutic effect. The "sinew-meridian system" composes of meridian-collateral system and tendon-skin system, in which the meridian-collateral system includes the twelve meridians, eight extra meridians and fifteen collaterals, being relevant with nutrition and blood, acting on transporting qi , blood and message; the tendon-skin system includes twelve sinew-meridians and twelve meridians of cutaneous regions, being relevant with defensive qi , acting on governing the motor function and protecting the body.

  1. Iron hypothesis of cardiovascular disease: still controversial.

    Science.gov (United States)

    Aursulesei, Viviana; Cozma, A; Krasniqi, A

    2014-01-01

    Iron hypothesis has been a controversial subject for over 30 years as many studies support its role as a risk factor for cardiovascular disease, while other studies found no evidence to support it. The conflicting results are accounted for by the non-homogeneity of trial design in terms of population inclusion criteria and different endpoints, non-uniform use of parameters for assessing iron role, and incomplete understanding of the mechanisms of action. The nature of iron is dual, being of crucial importance for the human body, but also toxic as "free iron" induces oxidative stress. Under physiological conditions, there are efficient and complex mechanisms against iron-induced oxidative stress, which could be reproduced for creating new, intelligent antioxidants. Iron depletion improves the cardiovascular prognosis only if serum concentration is at the lowest limit of normal ranges. However, low iron levels and the type of dietary iron intake correlate with atherosclerotic cardiovascular disease, influence the ischemic endpoints in the elderly, and exert negative impact on heart failure prognosis. So far, the causal relation and involved mechanisms are not fully elucidated. Iron overload is a difficult and frequent condition, involving the cardiovascular system by specific pathogenic pathways, therefore determining a particular form of restrictive cardiomyopathy and vaso-occlusive arterial damage.

  2. The social brain hypothesis of schizophrenia

    Science.gov (United States)

    BURNS, JONATHAN

    2006-01-01

    The social brain hypothesis is a useful heuristic for understanding schizophrenia. It focuses attention on the core Bleulerian concept of autistic alienation and is consistent with well-replicated findings of social brain dysfunction in schizophrenia as well as contemporary theories of human cognitive and brain evolution. The contributions of Heidegger, Merleau-Ponty and Wittgenstein allow us to arrive at a new "philosophy of interpersonal relatedness", which better reflects the "embodied mind" and signifies the end of Cartesian dualistic thinking. In this paper I review the evolution, development and neurobiology of the social brain - the anatomical and functional substrate for adaptive social behaviour and cognition. Functional imaging identifies fronto-temporal and fronto-parietal cortical networks as comprising the social brain, while the discovery of "mirror neurons" provides an understanding of social cognition at a cellular level. Patients with schizophrenia display abnormalities in a wide range of social cognition tasks such as emotion recognition, theory of mind and affective responsiveness. Furthermore, recent research indicates that schizophrenia is a disorder of functional and structural connectivity of social brain networks. These findings lend support to the claim that schizophrenia represents a costly by-product of social brain evolution in Homo sapiens. Individuals with this disorder find themselves seriously disadvantaged in the social arena and vulnerable to the stresses of their complex social environments. This state of "disembodiment" and interpersonal alienation is the core phenomenon of schizophrenia and the root cause of intolerable suffering in the lives of those affected. PMID:16946939

  3. Impulse Control Disorders - The Continuum Hypothesis.

    Science.gov (United States)

    Stenberg, Georg

    2016-01-01

    The group Parkinson Inside Out is composed of health professionals and academic researchers who have been diagnosed with Parkinson's Disease. In our discussions we try to make use of both our inside perspective as patients, and our outside perspective as professionals. In this paper, we apply the two perspectives to the Impulse Control Disorders. These impulsive behaviour patterns are thought to be relatively uncommon side effects of some of the medication used in dopamine replacement therapy. The phenomenon is usually described as relatively rare (controlling impulses is a very common experience for patients undergoing dopamine replacement therapy. They result from difficulties in decision making engendered by variations in dopamine accessibility in the reward centre of the brain. Only in a minority do the consequences grow to the damaging proportions of a disorder, but most patients are probably affected to some degree. Seeing, and measuring, decision difficulties as a continuous dimension, rather than as a discrete category, brings increased possibilities for early detection and continuous monitoring. With reliable measures of the propensity for impulsive decision making, it may become possible to both reap the benefits and avoid the dangers of the dopamine agonists. We point to ways of empirically testing our continuity hypothesis.

  4. The Stem Cell Hypothesis of Aging

    Directory of Open Access Journals (Sweden)

    Anna Meiliana

    2010-04-01

    Full Text Available BACKGROUND: There is probably no single way to age. Indeed, so far there is no single accepted explanation or mechanisms of aging (although more than 300 theories have been proposed. There is an overall decline in tissue regenerative potential with age, and the question arises as to whether this is due to the intrinsic aging of stem cells or rather to the impairment of stem cell function in the aged tissue environment. CONTENT: Recent data suggest that we age, in part, because our self-renewing stem cells grow old as a result of heritable intrinsic events, such as DNA damage, as well as extrinsic forces, such as changes in their supporting niches. Mechanisms that suppress the development of cancer, such as senescence and apoptosis, which rely on telomere shortening and the activities of p53 and p16INK4a may also induce an unwanted consequence: a decline in the replicative function of certain stem cells types with advancing age. This decrease regenerative capacity appears to pointing to the stem cell hypothesis of aging. SUMMARY: Recent evidence suggested that we grow old partly because of our stem cells grow old as a result of mechanisms that suppress the development of cancer over a lifetime. We believe that a further, more precise mechanistic understanding of this process will be required before this knowledge can be translated into human anti-aging therapies. KEYWORDS: stem cells, senescence, telomere, DNA damage, epigenetic, aging.

  5. Export-led Growth Hypothesis: Turkey Application

    Directory of Open Access Journals (Sweden)

    İsmail KÜÇÜKAKSOY

    2015-12-01

    Full Text Available This paper aims to investigate validity of “Export-led Growth Hypothesis” for Turkey using quarterly data in period from 2003:Q1 to 2015:Q1. Hypothesis argues that there is causality relationship from real export to real Gross Domestic Product (GDP. Johansen cointegration test, Gregory-Hansen cointegration test, Toda-Yamamoto causality test, Fully Modified Ordinary Least Squares (FMOLS, Canonical cointegrating regression (CCR and Dynamic ordinary least squares (DOLS methods were used in this study. Findings can be summarized as follows: a According to Johansen cointegration test there is no relationship among variables in the long-run whereas Gregory-Hansen cointegration test has determined relationship in the long-run; b According to Toda-Yamamoto causality test there is bidirectional causality between real export and real GDP. This finding proves the validity of “Export-led Growth Hypothesis” for Turkey; c According to FMOLS, CCR, DOLS methods a 1% increase in the real export increases the real GDP by 1.5195%, 1.5552%, 1.3171% respectively in the long-run. These methods prove the validity of “Export-led Growth Hypothesis” for Turkey.

  6. A matched filter hypothesis for cognitive control.

    Science.gov (United States)

    Chrysikou, Evangelia G; Weber, Matthew J; Thompson-Schill, Sharon L

    2014-09-01

    The prefrontal cortex exerts top-down influences on several aspects of higher-order cognition by functioning as a filtering mechanism that biases bottom-up sensory information toward a response that is optimal in context. However, research also indicates that not all aspects of complex cognition benefit from prefrontal regulation. Here we review and synthesize this research with an emphasis on the domains of learning and creative cognition, and outline how the appropriate level of cognitive control in a given situation can vary depending on the organism's goals and the characteristics of the given task. We offer a matched filter hypothesis for cognitive control, which proposes that the optimal level of cognitive control is task-dependent, with high levels of cognitive control best suited to tasks that are explicit, rule-based, verbal or abstract, and can be accomplished given the capacity limits of working memory and with low levels of cognitive control best suited to tasks that are implicit, reward-based, non-verbal or intuitive, and which can be accomplished irrespective of working memory limitations. Our approach promotes a view of cognitive control as a tool adapted to a subset of common challenges, rather than an all-purpose optimization system suited to every problem the organism might encounter. © 2013 Published by Elsevier Ltd.

  7. The Zinc Dyshomeostasis Hypothesis of Alzheimer's Disease

    Science.gov (United States)

    Craddock, Travis J. A.; Tuszynski, Jack A.; Chopra, Deepak; Casey, Noel; Goldstein, Lee E.; Hameroff, Stuart R.; Tanzi, Rudolph E.

    2012-01-01

    Alzheimer's disease (AD) is the most common form of dementia in the elderly. Hallmark AD neuropathology includes extracellular amyloid plaques composed largely of the amyloid-β protein (Aβ), intracellular neurofibrillary tangles (NFTs) composed of hyper-phosphorylated microtubule-associated protein tau (MAP-tau), and microtubule destabilization. Early-onset autosomal dominant AD genes are associated with excessive Aβ accumulation, however cognitive impairment best correlates with NFTs and disrupted microtubules. The mechanisms linking Aβ and NFT pathologies in AD are unknown. Here, we propose that sequestration of zinc by Aβ-amyloid deposits (Aβ oligomers and plaques) not only drives Aβ aggregation, but also disrupts zinc homeostasis in zinc-enriched brain regions important for memory and vulnerable to AD pathology, resulting in intra-neuronal zinc levels, which are either too low, or excessively high. To evaluate this hypothesis, we 1) used molecular modeling of zinc binding to the microtubule component protein tubulin, identifying specific, high-affinity zinc binding sites that influence side-to-side tubulin interaction, the sensitive link in microtubule polymerization and stability. We also 2) performed kinetic modeling showing zinc distribution in extra-neuronal Aβ deposits can reduce intra-neuronal zinc binding to microtubules, destabilizing microtubules. Finally, we 3) used metallomic imaging mass spectrometry (MIMS) to show anatomically-localized and age-dependent zinc dyshomeostasis in specific brain regions of Tg2576 transgenic, mice, a model for AD. We found excess zinc in brain regions associated with memory processing and NFT pathology. Overall, we present a theoretical framework and support for a new theory of AD linking extra-neuronal Aβ amyloid to intra-neuronal NFTs and cognitive dysfunction. The connection, we propose, is based on β-amyloid-induced alterations in zinc ion concentration inside neurons affecting stability of polymerized

  8. The zinc dyshomeostasis hypothesis of Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Travis J A Craddock

    Full Text Available Alzheimer's disease (AD is the most common form of dementia in the elderly. Hallmark AD neuropathology includes extracellular amyloid plaques composed largely of the amyloid-β protein (Aβ, intracellular neurofibrillary tangles (NFTs composed of hyper-phosphorylated microtubule-associated protein tau (MAP-tau, and microtubule destabilization. Early-onset autosomal dominant AD genes are associated with excessive Aβ accumulation, however cognitive impairment best correlates with NFTs and disrupted microtubules. The mechanisms linking Aβ and NFT pathologies in AD are unknown. Here, we propose that sequestration of zinc by Aβ-amyloid deposits (Aβ oligomers and plaques not only drives Aβ aggregation, but also disrupts zinc homeostasis in zinc-enriched brain regions important for memory and vulnerable to AD pathology, resulting in intra-neuronal zinc levels, which are either too low, or excessively high. To evaluate this hypothesis, we 1 used molecular modeling of zinc binding to the microtubule component protein tubulin, identifying specific, high-affinity zinc binding sites that influence side-to-side tubulin interaction, the sensitive link in microtubule polymerization and stability. We also 2 performed kinetic modeling showing zinc distribution in extra-neuronal Aβ deposits can reduce intra-neuronal zinc binding to microtubules, destabilizing microtubules. Finally, we 3 used metallomic imaging mass spectrometry (MIMS to show anatomically-localized and age-dependent zinc dyshomeostasis in specific brain regions of Tg2576 transgenic, mice, a model for AD. We found excess zinc in brain regions associated with memory processing and NFT pathology. Overall, we present a theoretical framework and support for a new theory of AD linking extra-neuronal Aβ amyloid to intra-neuronal NFTs and cognitive dysfunction. The connection, we propose, is based on β-amyloid-induced alterations in zinc ion concentration inside neurons affecting stability of

  9. The nitric oxide hypothesis of aging.

    Science.gov (United States)

    McCann, S M; Licinio, J; Wong, M L; Yu, W H; Karanth, S; Rettorri, V

    1998-01-01

    Nitric oxide (NO), generated by endothelial (e) NO synthase (NOS) and neuronal (n) NOS, plays a ubiquitous role in the body in controlling the function of almost every, if not every, organ system. Bacterial and viral products, such as bacterial lipopolysaccharide (LPS), induce inducible (i) NOS synthesis that produces massive amounts of NO toxic to the invading viruses and bacteria, but also host cells by inactivation of enzymes leading to cell death. The actions of all forms of NOS are mediated not only by the free radical oxidant properties of this soluble gas, but also by its activation of guanylate cyclase (GC), leading to the production of cyclic guanosine monophosphate (cGMP) that mediates many of its physiological actions. In addition, NO activates cyclooxygenase and lipoxygenase, leading to the production of physiologically relevant quantities of prostaglandin E2 (PGE2) and leukotrienes. In the case of iNOS, the massive release of NO, PGE2, and leukotrienes produces toxic effects. Systemic injection of LPS causes induction of interleukin (IL)-1 beta mRNA followed by IL-beta synthesis that induces iNOS mRNA with a latency of two and four hours, respectively, in the anterior pituitary and pineal glands, meninges, and choroid plexus, regions outside the blood-brain barrier, and shortly thereafter, in hypothalamic regions, such as the temperature-regulating centers, paraventricular nucleus containing releasing and inhibiting hormone neurons, and the arcuate nucleus, a region containing these neurons and axons bound for the median eminence. We are currently determining if LPS similarly activates cytokine and iNOS production in the cardiovascular system and the gonads. Our hypothesis is that recurrent infections over the life span play a significant role in producing aging changes in all systems outside the blood-brain barrier via release of toxic quantities of NO. NO may be a major factor in the development of coronary heart disease (CHD). Considerable evidence

  10. Sparse Representation Based Binary Hypothesis Model for Hyperspectral Image Classification

    Directory of Open Access Journals (Sweden)

    Yidong Tang

    2016-01-01

    Full Text Available The sparse representation based classifier (SRC and its kernel version (KSRC have been employed for hyperspectral image (HSI classification. However, the state-of-the-art SRC often aims at extended surface objects with linear mixture in smooth scene and assumes that the number of classes is given. Considering the small target with complex background, a sparse representation based binary hypothesis (SRBBH model is established in this paper. In this model, a query pixel is represented in two ways, which are, respectively, by background dictionary and by union dictionary. The background dictionary is composed of samples selected from the local dual concentric window centered at the query pixel. Thus, for each pixel the classification issue becomes an adaptive multiclass classification problem, where only the number of desired classes is required. Furthermore, the kernel method is employed to improve the interclass separability. In kernel space, the coding vector is obtained by using kernel-based orthogonal matching pursuit (KOMP algorithm. Then the query pixel can be labeled by the characteristics of the coding vectors. Instead of directly using the reconstruction residuals, the different impacts the background dictionary and union dictionary have on reconstruction are used for validation and classification. It enhances the discrimination and hence improves the performance.

  11. Men’s Perception of Raped Women: Test of the Sexually Transmitted Disease Hypothesis and the Cuckoldry Hypothesis

    Directory of Open Access Journals (Sweden)

    Prokop Pavol

    2016-06-01

    Full Text Available Rape is a recurrent adaptive problem of female humans and females of a number of non-human animals. Rape has various physiological and reproductive costs to the victim. The costs of rape are furthermore exaggerated by social rejection and blaming of a victim, particularly by men. The negative perception of raped women by men has received little attention from an evolutionary perspective. Across two independent studies, we investigated whether the risk of sexually transmitted diseases (the STD hypothesis, Hypothesis 1 or paternity uncertainty (the cuckoldry hypothesis, Hypothesis 2 influence the negative perception of raped women by men. Raped women received lower attractiveness score than non-raped women, especially in long-term mate attractiveness score. The perceived attractiveness of raped women was not influenced by the presence of experimentally manipulated STD cues on faces of putative rapists. Women raped by three men received lower attractiveness score than women raped by one man. These results provide stronger support for the cuckoldry hypothesis (Hypothesis 2 than for the STD hypothesis (Hypothesis 1. Single men perceived raped women as more attractive than men in a committed relationship (Hypothesis 3, suggesting that the mating opportunities mediate men’s perception of victims of rape. Overall, our results suggest that the risk of cuckoldry underlie the negative perception of victims of rape by men rather than the fear of disease transmission.

  12. The Role of Hypothesis in Constructive Design Research

    DEFF Research Database (Denmark)

    Bang, Anne Louise; Krogh, Peter; Ludvigsen, Martin

    2012-01-01

    and solid perspective on how to keep constructive design research on track, this paper offers a model for understanding the role of hypothesis in constructive design research. The model allows for understanding the hypothesis’s relation to research motivation, questions, experiments, evaluation...... position of the hypothesis as a key-governing element even in artistic led research processes....

  13. Dynamical agents' strategies and the fractal market hypothesis

    Czech Academy of Sciences Publication Activity Database

    Vácha, Lukáš; Vošvrda, Miloslav

    2005-01-01

    Roč. 14, č. 2 (2005), s. 172-179 ISSN 1210-0455 Grant - others:GA UK(CZ) 454/2004/A EK/FSV Institutional research plan: CEZ:AV0Z10750506 Keywords : efficient market hypothesis * fractal market hypothesis * agent's investment horizons Subject RIV: AH - Economics

  14. An Exercise for Illustrating the Logic of Hypothesis Testing

    Science.gov (United States)

    Lawton, Leigh

    2009-01-01

    Hypothesis testing is one of the more difficult concepts for students to master in a basic, undergraduate statistics course. Students often are puzzled as to why statisticians simply don't calculate the probability that a hypothesis is true. This article presents an exercise that forces students to lay out on their own a procedure for testing a…

  15. A new 'hidden colour hypothesis' in hadron physics

    Indian Academy of Sciences (India)

    A new `hidden colour hypothesis' within the framework of QCD, as an extension of and in keeping with the spirit of the `colour singlet hypothesis' is hereby proposed. As such it should play a role in a consistent description of exotic hadrons, such as diquonia, pentaquarks, dibaryons etc. How these exotic hadrons are ...

  16. A new 'hidden colour hypothesis' in hadron physics

    Indian Academy of Sciences (India)

    Abstract. A new 'hidden colour hypothesis' within the framework of QCD, as an exten- sion of and in keeping with the spirit of the 'colour singlet hypothesis' is hereby proposed. As such it should play a role in a consistent description of exotic hadrons, such as diquonia, pentaquarks, dibaryons etc. How these exotic hadrons ...

  17. New Hypothesis for SOFC Ceramic Oxygen Electrode Mechanisms

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Chatzichristodoulou, Christodoulos; Graves, Christopher R.

    2016-01-01

    A new hypothesis for the electrochemical reaction mechanism in solid oxide cell ceramic oxygen electrodes is proposed based on literature including our own results. The hypothesis postulates that the observed thin layers of SrO-La2O3 on top of ceramic perovskite and other Ruddlesden-Popper...

  18. The Younger Dryas impact hypothesis: A critical review

    NARCIS (Netherlands)

    van Hoesel, A.; Hoek, W.Z.; Pennock, G.M.; Drury, Martyn

    2014-01-01

    The Younger Dryas impact hypothesis suggests that multiple extraterrestrial airbursts or impacts resulted in the Younger Dryas cooling, extensive wildfires, megafaunal extinctions and changes in human population. After the hypothesis was first published in 2007, it gained much criticism, as the

  19. New methods of testing nonlinear hypothesis using iterative NLLS estimator

    Science.gov (United States)

    Mahaboob, B.; Venkateswarlu, B.; Mokeshrayalu, G.; Balasiddamuni, P.

    2017-11-01

    This research paper discusses the method of testing nonlinear hypothesis using iterative Nonlinear Least Squares (NLLS) estimator. Takeshi Amemiya [1] explained this method. However in the present research paper, a modified Wald test statistic due to Engle, Robert [6] is proposed to test the nonlinear hypothesis using iterative NLLS estimator. An alternative method for testing nonlinear hypothesis using iterative NLLS estimator based on nonlinear hypothesis using iterative NLLS estimator based on nonlinear studentized residuals has been proposed. In this research article an innovative method of testing nonlinear hypothesis using iterative restricted NLLS estimator is derived. Pesaran and Deaton [10] explained the methods of testing nonlinear hypothesis. This paper uses asymptotic properties of nonlinear least squares estimator proposed by Jenrich [8]. The main purpose of this paper is to provide very innovative methods of testing nonlinear hypothesis using iterative NLLS estimator, iterative NLLS estimator based on nonlinear studentized residuals and iterative restricted NLLS estimator. Eakambaram et al. [12] discussed least absolute deviation estimations versus nonlinear regression model with heteroscedastic errors and also they studied the problem of heteroscedasticity with reference to nonlinear regression models with suitable illustration. William Grene [13] examined the interaction effect in nonlinear models disused by Ai and Norton [14] and suggested ways to examine the effects that do not involve statistical testing. Peter [15] provided guidelines for identifying composite hypothesis and addressing the probability of false rejection for multiple hypotheses.

  20. Assess the Critical Period Hypothesis in Second Language Acquisition

    Science.gov (United States)

    Du, Lihong

    2010-01-01

    The Critical Period Hypothesis aims to investigate the reason for significant difference between first language acquisition and second language acquisition. Over the past few decades, researchers carried out a series of studies to test the validity of the hypothesis. Although there were certain limitations in these studies, most of their results…

  1. Revisiting the hypothesis-driven interview in a contemporary context.

    Science.gov (United States)

    Holmes, Alex; Singh, Bruce; McColl, Geoff

    2011-12-01

    The "hypothesis-driven interview" was articulated by George Engel as a method of raising and testing hypotheses in the process of building a biopsychosocial formulation and determining the most likely diagnosis. This interview was a forerunner of the modern medical interview as well as the contemporary psychiatric assessment. The objective of this article is to describe the hypothesis-driven interview and to explore its relationship with the contemporary medical interview. The literature on the medical and hypothesis-driven interview was reviewed. Key features of each were identified. The hypothesis-driven interview shares much with the contemporary medical interview. In addition, it enhances the application of communication skills and allows the interviewer to develop a formulation during the course of the assessment. The hypothesis-driven interview is well suited to the aims of a contemporary psychiatric assessment.

  2. Light extraction block with curved surface

    Science.gov (United States)

    Levermore, Peter; Krall, Emory; Silvernail, Jeffrey; Rajan, Kamala; Brown, Julia J.

    2016-03-22

    Light extraction blocks, and OLED lighting panels using light extraction blocks, are described, in which the light extraction blocks include various curved shapes that provide improved light extraction properties compared to parallel emissive surface, and a thinner form factor and better light extraction than a hemisphere. Lighting systems described herein may include a light source with an OLED panel. A light extraction block with a three-dimensional light emitting surface may be optically coupled to the light source. The three-dimensional light emitting surface of the block may includes a substantially curved surface, with further characteristics related to the curvature of the surface at given points. A first radius of curvature corresponding to a maximum principal curvature k.sub.1 at a point p on the substantially curved surface may be greater than a maximum height of the light extraction block. A maximum height of the light extraction block may be less than 50% of a maximum width of the light extraction block. Surfaces with cross sections made up of line segments and inflection points may also be fit to approximated curves for calculating the radius of curvature.

  3. How do Economic Growth Asymmetry and Inflation Expectations Affect Fisher Hypothesis and Fama’s Proxy Hypothesis?

    Directory of Open Access Journals (Sweden)

    Yuan-Ming Lee

    2017-12-01

    Full Text Available Based on the threshold panel data model, this study employs the quarterly panel data of 38 countries between 1981 and 2014 to test whether economic growth asymmetry, expected inflation, and unexpected inflation affect the Fisher hypothesis and Fama’s proxy hypothesis. The empirical results show the following: (1 When real economic growth rate is greater than the threshold (-0.009, Fisher hypothesis is supported. (2 When real economic growth rate is less than the threshold (-0.009, two scenarios hold true: before real variables are included, Fisher hypothesis is rejected; and when real variables are included, real economic growth is negative, inflation is expected, and thus, Fama’s hypothesis is supported.

  4. The linear hypothesis - an idea whose time has passed

    International Nuclear Information System (INIS)

    Tschaeche, A.N.

    1995-01-01

    The linear no-threshold hypothesis is the basis for radiation protection standards in the United States. In the words of the National Council on Radiation Protection and Measurements (NCRP), the hypothesis is: open-quotes In the interest of estimating effects in humans conservatively, it is not unreasonable to follow the assumption of a linear relationship between dose and effect in the low dose regions for which direct observational data are not available.close quotes The International Commission on Radiological Protection (ICRP) stated the hypothesis in a slightly different manner: open-quotes One such basic assumption ... is that ... there is ... a linear relationship without threshold between dose and the probability of an effect. The hypothesis was necessary 50 yr ago when it was first enunciated because the dose-effect curve for ionizing radiation for effects in humans was not known. The ICRP and NCRP needed a model to extrapolate high-dose effects to low-dose effects. So the linear no-threshold hypothesis was born. Certain details of the history of the development and use of the linear hypothesis are presented. In particular, use of the hypothesis by the U.S. regulatory agencies is examined. Over time, the sense of the hypothesis has been corrupted. The corruption of the hypothesis into the current paradigm of open-quote a little radiation, no matter how small, can and will harm youclose quotes is presented. The reasons the corruption occurred are proposed. The effects of the corruption are enumerated, specifically, the use of the corruption by the antinuclear forces in the United States and some of the huge costs to U.S. taxpayers due to the corruption. An alternative basis for radiation protection standards to assure public safety, based on the weight of scientific evidence on radiation health effects, is proposed

  5. Vehicle Detection Based on Probability Hypothesis Density Filter

    Directory of Open Access Journals (Sweden)

    Feihu Zhang

    2016-04-01

    Full Text Available In the past decade, the developments of vehicle detection have been significantly improved. By utilizing cameras, vehicles can be detected in the Regions of Interest (ROI in complex environments. However, vision techniques often suffer from false positives and limited field of view. In this paper, a LiDAR based vehicle detection approach is proposed by using the Probability Hypothesis Density (PHD filter. The proposed approach consists of two phases: the hypothesis generation phase to detect potential objects and the hypothesis verification phase to classify objects. The performance of the proposed approach is evaluated in complex scenarios, compared with the state-of-the-art.

  6. Biostatistics series module 2: Overview of hypothesis testing

    Directory of Open Access Journals (Sweden)

    Avijit Hazra

    2016-01-01

    Full Text Available Hypothesis testing (or statistical inference is one of the major applications of biostatistics. Much of medical research begins with a research question that can be framed as a hypothesis. Inferential statistics begins with a null hypothesis that reflects the conservative position of no change or no difference in comparison to baseline or between groups. Usually, the researcher has reason to believe that there is some effect or some difference which is the alternative hypothesis. The researcher therefore proceeds to study samples and measure outcomes in the hope of generating evidence strong enough for the statistician to be able to reject the null hypothesis. The concept of the P value is almost universally used in hypothesis testing. It denotes the probability of obtaining by chance a result at least as extreme as that observed, even when the null hypothesis is true and no real difference exists. Usually, if P is < 0.05 the null hypothesis is rejected and sample results are deemed statistically significant. With the increasing availability of computers and access to specialized statistical software, the drudgery involved in statistical calculations is now a thing of the past, once the learning curve of the software has been traversed. The life sciences researcher is therefore free to devote oneself to optimally designing the study, carefully selecting the hypothesis tests to be applied, and taking care in conducting the study well. Unfortunately, selecting the right test seems difficult initially. Thinking of the research hypothesis as addressing one of five generic research questions helps in selection of the right hypothesis test. In addition, it is important to be clear about the nature of the variables (e.g., numerical vs. categorical; parametric vs. nonparametric and the number of groups or data sets being compared (e.g., two or more than two at a time. The same research question may be explored by more than one type of hypothesis test

  7. Temperature Dependence of Arn + Cluster Backscattering from Polymer Surfaces: a New Method to Determine the Surface Glass Transition Temperature

    Science.gov (United States)

    Poleunis, Claude; Cristaudo, Vanina; Delcorte, Arnaud

    2018-01-01

    In this work, time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used to study the intensity variations of the backscattered Arn + clusters as a function of temperature for several amorphous polymer surfaces (polyolefins, polystyrene, and polymethyl methacrylate). For all these investigated polymers, our results show a transition of the ratio Ar2 +/(Ar2 + + Ar3 +) when the temperature is scanned from -120 °C to +125 °C (the exact limits depend on the studied polymer). This transition generally spans over a few tens of degrees and the temperature of the inflection point of each curve is always lower than the bulk glass transition temperature (Tg) reported for the considered polymer. Due to the surface sensitivity of the cluster backscattering process (several nanometers), the presented analysis could provide a new method to specifically evaluate a surface transition temperature of polymers, with the same lateral resolution as the gas cluster beam. [Figure not available: see fulltext.

  8. Temperature Dependence of Arn+ Cluster Backscattering from Polymer Surfaces: a New Method to Determine the Surface Glass Transition Temperature.

    Science.gov (United States)

    Poleunis, Claude; Cristaudo, Vanina; Delcorte, Arnaud

    2018-01-01

    In this work, time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used to study the intensity variations of the backscattered Ar n + clusters as a function of temperature for several amorphous polymer surfaces (polyolefins, polystyrene, and polymethyl methacrylate). For all these investigated polymers, our results show a transition of the ratio Ar 2 + /(Ar 2 + + Ar 3 + ) when the temperature is scanned from -120 °C to +125 °C (the exact limits depend on the studied polymer). This transition generally spans over a few tens of degrees and the temperature of the inflection point of each curve is always lower than the bulk glass transition temperature (T g ) reported for the considered polymer. Due to the surface sensitivity of the cluster backscattering process (several nanometers), the presented analysis could provide a new method to specifically evaluate a surface transition temperature of polymers, with the same lateral resolution as the gas cluster beam. Graphical abstract ᅟ.

  9. Using the Gaia Hypothesis to Synthesize an Introductory Biology Course.

    Science.gov (United States)

    Baker, Gail A.

    1993-01-01

    The Gaia Hypothesis emphasizes the interactions and feedback mechanisms between the living and nonliving process that take place on Earth. Employing this concept in instruction can emphasize the interdisciplinary nature of science and give a planetary perspective of biology. (PR)

  10. Update on the "Dutch hypothesis" for chronic respiratory disease

    DEFF Research Database (Denmark)

    Vestbo, J; Prescott, E

    1998-01-01

    BACKGROUND: Many patients with chronic obstructive lung disease show increased airways responsiveness to histamine. We investigated the hypothesis that increased airways responsiveness predicts the development and remission of chronic respiratory symptoms. METHODS: We used data from 24-year follo...

  11. Incidence of allergy and atopic disorders and hygiene hypothesis.

    Czech Academy of Sciences Publication Activity Database

    Bencko, V.; Šíma, Petr

    2017-01-01

    Roč. 2, 6 March (2017), č. článku 1244. ISSN 2474-1663 Institutional support: RVO:61388971 Keywords : allergy disorders * atopic disorders * hygiene hypothesis Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology

  12. Cross-system log file analysis for hypothesis testing

    NARCIS (Netherlands)

    Glahn, Christian

    2008-01-01

    Glahn, C. (2008). Cross-system log file analysis for hypothesis testing. Presented at Empowering Learners for Lifelong Competence Development: pedagogical, organisational and technological issues. 4th TENCompetence Open Workshop. April, 10, 2008, Madrid, Spain.

  13. Crustal Plateaus as Ancient Large Impact Features: A Hypothesis

    Science.gov (United States)

    Hansen, V. L.

    2005-03-01

    An alternate hypothesis of crustal plateau formation through deformation and progressive crystallization of a huge lava pond, that results from massive melting of the mantle due to bolide impact with ancient thin Venus lithosphere is presented.

  14. The hypothesis of superluminal neutrinos: Comparing OPERA with other data

    DEFF Research Database (Denmark)

    Drago, A.; Masina, I.; Pagliara, G.

    2012-01-01

    The OPERA Collaboration reported evidence for muonic neutrinos traveling slightly faster than light in vacuum. While waiting further checks from the experimental community, here we aim at exploring some theoretical consequences of the hypothesis that muonic neutrinos are superluminal, considering...

  15. On a Misconception Involving Point Collocation and the Rayleigh Hypothesis

    DEFF Research Database (Denmark)

    Christiansen, Søren; Kleinman, Ralph E.

    1996-01-01

    It is shown that the Rayleigh hypothesis does notgovern convergence of the simple point collocationapproach to the numerical solutions of scatteringby a sinusoidal grating. A recently developed numerical technique, interval arithmetic, is employed to perform some decisive numerical experiments...

  16. History of the emergence of the electron spin hypothesis

    International Nuclear Information System (INIS)

    Fu Haihui

    2002-01-01

    Electron spin is an important concept in atomic physics and quantum mechanics. The emergence and acceptance of the hypothesis of electron spin has a special place in history, and is reviewed here from three aspects

  17. Alzheimer's disease: the amyloid hypothesis and the Inverse Warburg effect

    KAUST Repository

    Demetrius, Lloyd A.

    2015-01-14

    Epidemiological and biochemical studies show that the sporadic forms of Alzheimer\\'s disease (AD) are characterized by the following hallmarks: (a) An exponential increase with age; (b) Selective neuronal vulnerability; (c) Inverse cancer comorbidity. The present article appeals to these hallmarks to evaluate and contrast two competing models of AD: the amyloid hypothesis (a neuron-centric mechanism) and the Inverse Warburg hypothesis (a neuron-astrocytic mechanism). We show that these three hallmarks of AD conflict with the amyloid hypothesis, but are consistent with the Inverse Warburg hypothesis, a bioenergetic model which postulates that AD is the result of a cascade of three events—mitochondrial dysregulation, metabolic reprogramming (the Inverse Warburg effect), and natural selection. We also provide an explanation for the failures of the clinical trials based on amyloid immunization, and we propose a new class of therapeutic strategies consistent with the neuroenergetic selection model.

  18. Interpretative possibilities and limitations of Saxe/Goldstein hypothesis

    Directory of Open Access Journals (Sweden)

    André Strauss

    2012-08-01

    Full Text Available The Saxe/Goldstein Hypothesis was generated within the processual archaeology milieu and therefore it was supposed to allow reconstructing the social dimensions of past populations by studying their mortuary practices. In its original form stated that the emergency of formal cemeteries would be the result of an increase on the competition for vital resources. This would lead to the formation of corporate groups of descent whose main objectives were to monopolize the access to vital resources. Later, a reformulated version of this hypothesis was developed emphasizing the relationship between the presence of formal cemeteries and mobility pattern of human groups. In this contribution we present a critical review on the formation of this hypothesis and discuss its limitations. Finally, two examples taken from the Brazilian archaeological record are used to show how the lack of a critical posture in relation to the Saxe/Goldstein Hypothesis may lead to fragile interpretations of the archaeological record.

  19. Hypothesis Testing of Parameters for Ordinary Linear Circular Regression

    Directory of Open Access Journals (Sweden)

    Abdul Ghapor Hussin

    2006-07-01

    Full Text Available This paper presents the hypothesis testing of parameters for ordinary linear circular regression model assuming the circular random error distributed as von Misses distribution. The main interests are in testing of the intercept and slope parameter of the regression line. As an illustration, this hypothesis testing will be used in analyzing the wind and wave direction data recorded by two different techniques which are HF radar system and anchored wave buoy.

  20. The comprehension of sentences with unaccusative verbs in aphasia: a test of the intervener hypothesis.

    Science.gov (United States)

    Sullivan, Natalie; Walenski, Matthew; Love, Tracy; Shapiro, Lewis P

    2017-01-01

    It is well accepted that individuals with agrammatic Broca's aphasia have difficulty comprehending some sentences with filler-gap dependencies. While investigations of these difficulties have been conducted with several different sentence types (e.g., object relatives, Wh -questions), we explore sentences containing unaccusative verbs, which arguably have a single noun phrase (NP) that is base-generated in object position but then is displaced to surface subject position. Unaccusative verbs provide an ideal test case for a particular hypothesis about the comprehension disorder-the Intervener Hypothesis-that posits that the difficulty individuals with agrammatic Broca's aphasia have comprehending sentences containing filler-gap dependencies results from similarity-based interference caused by the presence of an intervening NP between the two elements of a syntactic chain. To assess a particular account of the comprehension deficit in agrammatic Broca's aphasia-the Intervener Hypothesis. We used a sentence-picture matching task to determine if listeners with agrammatic Broca's aphasia (LWBA) and age-matched neurologically unimpaired controls (AMC) have difficulty comprehending unaccusative verbs when placed in subject relative and complement phrase (CP) constructions. We found above-chance comprehension of both sentence constructions with the AMC participants. In contrast, we found above-chance comprehension of CP sentences containing unaccusative verbs but poor comprehension of subject relative sentences containing unaccusative verbs for the LWBA. These results provide support for the Intervener Hypothesis, wherein the presence of an intervening NP between two elements of a filler-gap dependency adversely affects sentence comprehension.

  1. Testing the null hypothesis: the forgotten legacy of Karl Popper?

    Science.gov (United States)

    Wilkinson, Mick

    2013-01-01

    Testing of the null hypothesis is a fundamental aspect of the scientific method and has its basis in the falsification theory of Karl Popper. Null hypothesis testing makes use of deductive reasoning to ensure that the truth of conclusions is irrefutable. In contrast, attempting to demonstrate the new facts on the basis of testing the experimental or research hypothesis makes use of inductive reasoning and is prone to the problem of the Uniformity of Nature assumption described by David Hume in the eighteenth century. Despite this issue and the well documented solution provided by Popper's falsification theory, the majority of publications are still written such that they suggest the research hypothesis is being tested. This is contrary to accepted scientific convention and possibly highlights a poor understanding of the application of conventional significance-based data analysis approaches. Our work should remain driven by conjecture and attempted falsification such that it is always the null hypothesis that is tested. The write up of our studies should make it clear that we are indeed testing the null hypothesis and conforming to the established and accepted philosophical conventions of the scientific method.

  2. Surface potential at the hematite (001) crystal plane in aqueous environments and the effects of prolonged aging in water

    Science.gov (United States)

    Lützenkirchen, Johannes; Preočanin, Tajana; Stipić, Filip; Heberling, Frank; Rosenqvist, Jörgen; Kallay, Nikola

    2013-11-01

    The surface potentials of a (0 0 1) terminated hematite crystal that was annealed at high-temperature were measured as a function of pH by means of the corresponding single crystal electrode. The surface potential at a given pH did not depend on the electrolyte concentration, and was found to exhibit an inflection point. The shape of the function is in phenomenological agreement with the presence of two distinct surface terminations (O and Fe) that have been previously reported for this surface. Aging of the annealed hematite surface, in aqueous electrolyte medium over 2 weeks, leads to a drastic change in the surface potential pH curve. The surface potential becomes that of the ideal O termination. While the O termination data can be modeled using the MUSIC approach, the initial sample that is expected to correspond to the two-domain surface with O and Fe terminations cannot be described within the MUSIC approach based on previously published surface diffraction data. However, the experimental data fall between the O and Fe termination limiting cases when the point of zero potential is placed at the inflection point. The fact that a surface with the two terminations cannot be modeled may be attributed to various issues, three of which are discussed: (i) the general difficulty to average the potential arising from both terminations, which furthermore are short-circuited via the crystal, (ii) the difficulty of treating patchwise heterogeneous surfaces in surface complexation models, and (iii) the incapability of surface complexation models in their present form to describe potential gradients within the solid. Conclusively, we interpret our results as a transformation from a bi-domain surface, to a single domain surface over time under conditions where bulk hematite solubility is low. Accordingly, the oxygen terminated domain should be the more stable one at this single crystal surface at our experimental conditions.

  3. Social learning and evolution: the cultural intelligence hypothesis.

    Science.gov (United States)

    van Schaik, Carel P; Burkart, Judith M

    2011-04-12

    If social learning is more efficient than independent individual exploration, animals should learn vital cultural skills exclusively, and routine skills faster, through social learning, provided they actually use social learning preferentially. Animals with opportunities for social learning indeed do so. Moreover, more frequent opportunities for social learning should boost an individual's repertoire of learned skills. This prediction is confirmed by comparisons among wild great ape populations and by social deprivation and enculturation experiments. These findings shaped the cultural intelligence hypothesis, which complements the traditional benefit hypotheses for the evolution of intelligence by specifying the conditions in which these benefits can be reaped. The evolutionary version of the hypothesis argues that species with frequent opportunities for social learning should more readily respond to selection for a greater number of learned skills. Because improved social learning also improves asocial learning, the hypothesis predicts a positive interspecific correlation between social-learning performance and individual learning ability. Variation among primates supports this prediction. The hypothesis also predicts that more heavily cultural species should be more intelligent. Preliminary tests involving birds and mammals support this prediction too. The cultural intelligence hypothesis can also account for the unusual cognitive abilities of humans, as well as our unique mechanisms of skill transfer.

  4. Investigating the environmental Kuznets curve hypothesis in Vietnam

    International Nuclear Information System (INIS)

    Al-Mulali, Usama; Saboori, Behnaz; Ozturk, Ilhan

    2015-01-01

    This study investigates the existence of the environmental Kuznets curve (EKC) hypothesis in Vietnam during the period 1981–2011. To realize the goals of this study, a pollution model was established applying the Autoregressive Distributed Lag (ARDL) methodology. The results revealed that the pollution haven hypothesis does exist in Vietnam because capital increases pollution. In addition, imports also increase pollution which indicates that most of Vietnam's imported products are energy intensive and highly polluted. However, exports have no effect on pollution which indicates that the level of exports is not significant enough to affect pollution. Moreover, fossil fuel energy consumption increases pollution while renewable energy consumption has no significant effect in reducing pollution. Furthermore, labor force reduces pollution since most of Vietnam's labor force is in the agricultural and services sectors which are less energy intensive than the industrial sector. Based on the obtained results, the EKC hypothesis does not exist because the relationship between GDP and pollution is positive in both the short and long run. - Highlights: • The environmental Kuznets curve (EKC) hypothesis in Vietnam is investigated. • The Autoregressive Distributed Lag (ARDL) methodology was utilized. • The EKC hypothesis does not exist

  5. Sexual differentiation and the neuroendocrine hypothesis of autism.

    Science.gov (United States)

    Aiello, Timothy P; Whitaker-Azmitia, Patricia M

    2011-10-01

    The phenotypic expression of autism spectrum disorders varies widely in severity and characteristics and it is, therefore, likely that a number of etiological factors are involved. However, one finding which has been found consistently is that there is a greater incidence of autism in boys than girls. Recently, attention has been given to the extreme male hypothesis-that is that autism behaviors are an extreme form of typical male behaviors, including lack of empathy and language deficits but an increase in so-called systemizing behaviors, such as attention to detail and collecting. This points to the possibility that an alteration during sexual differentiation of the brain may occur in autism. During sexual differentiation of the brain, two brain regions are highly sexually dimorphic-the amygdala and the hypothalamus. Both of these regions are also implicated in the neuroendocrine hypothesis of autism, wherein a balance between oxytocin and cortisol may contribute to the disorder. We are thus proposing that the extreme male hypothesis and the neuroendocrine hypothesis are in fact compatible in that sexual differentiation of the brain towards an extreme male phenotype would result in the neuroendocrine changes proposed in autism. We have preliminary data, treating developing rat pups with the differentiating hormone 17-β estradiol during a critical time and showing changes in social behaviors and oxytocin, to support this hypothesis. Further studies should be undertaken to confirm the role of extremes of normal sexual differentiation in producing the neuroendocrine changes associated with autism. Copyright © 2011 Wiley-Liss, Inc.

  6. A large scale test of the gaming-enhancement hypothesis.

    Science.gov (United States)

    Przybylski, Andrew K; Wang, John C

    2016-01-01

    A growing research literature suggests that regular electronic game play and game-based training programs may confer practically significant benefits to cognitive functioning. Most evidence supporting this idea, the gaming-enhancement hypothesis , has been collected in small-scale studies of university students and older adults. This research investigated the hypothesis in a general way with a large sample of 1,847 school-aged children. Our aim was to examine the relations between young people's gaming experiences and an objective test of reasoning performance. Using a Bayesian hypothesis testing approach, evidence for the gaming-enhancement and null hypotheses were compared. Results provided no substantive evidence supporting the idea that having preference for or regularly playing commercially available games was positively associated with reasoning ability. Evidence ranged from equivocal to very strong in support for the null hypothesis over what was predicted. The discussion focuses on the value of Bayesian hypothesis testing for investigating electronic gaming effects, the importance of open science practices, and pre-registered designs to improve the quality of future work.

  7. Social learning and evolution: the cultural intelligence hypothesis

    Science.gov (United States)

    van Schaik, Carel P.; Burkart, Judith M.

    2011-01-01

    If social learning is more efficient than independent individual exploration, animals should learn vital cultural skills exclusively, and routine skills faster, through social learning, provided they actually use social learning preferentially. Animals with opportunities for social learning indeed do so. Moreover, more frequent opportunities for social learning should boost an individual's repertoire of learned skills. This prediction is confirmed by comparisons among wild great ape populations and by social deprivation and enculturation experiments. These findings shaped the cultural intelligence hypothesis, which complements the traditional benefit hypotheses for the evolution of intelligence by specifying the conditions in which these benefits can be reaped. The evolutionary version of the hypothesis argues that species with frequent opportunities for social learning should more readily respond to selection for a greater number of learned skills. Because improved social learning also improves asocial learning, the hypothesis predicts a positive interspecific correlation between social-learning performance and individual learning ability. Variation among primates supports this prediction. The hypothesis also predicts that more heavily cultural species should be more intelligent. Preliminary tests involving birds and mammals support this prediction too. The cultural intelligence hypothesis can also account for the unusual cognitive abilities of humans, as well as our unique mechanisms of skill transfer. PMID:21357223

  8. A large scale test of the gaming-enhancement hypothesis

    Directory of Open Access Journals (Sweden)

    Andrew K. Przybylski

    2016-11-01

    Full Text Available A growing research literature suggests that regular electronic game play and game-based training programs may confer practically significant benefits to cognitive functioning. Most evidence supporting this idea, the gaming-enhancement hypothesis, has been collected in small-scale studies of university students and older adults. This research investigated the hypothesis in a general way with a large sample of 1,847 school-aged children. Our aim was to examine the relations between young people’s gaming experiences and an objective test of reasoning performance. Using a Bayesian hypothesis testing approach, evidence for the gaming-enhancement and null hypotheses were compared. Results provided no substantive evidence supporting the idea that having preference for or regularly playing commercially available games was positively associated with reasoning ability. Evidence ranged from equivocal to very strong in support for the null hypothesis over what was predicted. The discussion focuses on the value of Bayesian hypothesis testing for investigating electronic gaming effects, the importance of open science practices, and pre-registered designs to improve the quality of future work.

  9. RPD-based Hypothesis Reasoning for Cyber Situation Awareness

    Science.gov (United States)

    Yen, John; McNeese, Michael; Mullen, Tracy; Hall, David; Fan, Xiaocong; Liu, Peng

    Intelligence workers such as analysts, commanders, and soldiers often need a hypothesis reasoning framework to gain improved situation awareness of the highly dynamic cyber space. The development of such a framework requires the integration of interdisciplinary techniques, including supports for distributed cognition (human-in-the-loop hypothesis generation), supports for team collaboration (identification of information for hypothesis evaluation), and supports for resource-constrained information collection (hypotheses competing for information collection resources). We here describe a cognitively-inspired framework that is built upon Klein’s recognition-primed decision model and integrates the three components of Endsley’s situation awareness model. The framework naturally connects the logic world of tools for cyber situation awareness with the mental world of human analysts, enabling the perception, comprehension, and prediction of cyber situations for better prevention, survival, and response to cyber attacks by adapting missions at the operational, tactical, and strategic levels.

  10. Unicorns do exist: a tutorial on "proving" the null hypothesis.

    Science.gov (United States)

    Streiner, David L

    2003-12-01

    Introductory statistics classes teach us that we can never prove the null hypothesis; all we can do is reject or fail to reject it. However, there are times when it is necessary to try to prove the nonexistence of a difference between groups. This most often happens within the context of comparing a new treatment against an established one and showing that the new intervention is not inferior to the standard. This article first outlines the logic of "noninferiority" testing by differentiating between the null hypothesis (that which we are trying to nullify) and the "nill" hypothesis (there is no difference), reversing the role of the null and alternate hypotheses, and defining an interval within which groups are said to be equivalent. We then work through an example and show how to calculate sample sizes for noninferiority studies.

  11. Exercise Test Performance Reveals Evidence of the Cardiorespiratory Fitness Hypothesis.

    Science.gov (United States)

    Billinger, Sandra A; Vidoni, Eric D; Morris, Jill K; Thyfault, John P; Burns, Jeffrey M

    2017-04-01

    Positive physiologic and cognitive responses to aerobic exercise have resulted in a proposed cardiorespiratory (CR) fitness hypothesis in which fitness gains drive changes leading to cognitive benefit. The purpose of this study was to directly assess the CR fitness hypothesis. Using data from an aerobic exercise trial, we examined individuals who completed cardiopulmonary and cognitive testing at baseline and 26 weeks. Change in cognitive test performance was not related to CR fitness change (r 2 = .06, p = .06). However, in the subset of individuals who gave excellent effort during exercise testing, change in cognitive test performance was related to CR fitness change (r 2 = .33, p fitness hypothesis and mechanisms by which physiologic adaptation may drive cognitive change.

  12. Testing the double-deficit hypothesis in an adult sample.

    Science.gov (United States)

    Miller, Carlin J; Miller, Scott R; Bloom, Juliana S; Jones, Lauren; Lindstrom, William; Craggs, Jason; Garcia-Barrera, Mauricio; Semrud-Clikeman, Margaret; Gilger, Jeffrey W; Hynd, George W

    2006-06-01

    The double-deficit hypothesis of dyslexia posits that reading deficits are more severe in individuals with weaknesses in phonological awareness and rapid naming than in individuals with deficits in only one of these reading composite skills. In this study, the hypothesis was tested in an adult sample as a model of reading achievement. Participants were parents of children referred for evaluation of reading difficulties. Approximately half of all participants reported difficulty learning to read in childhood and a small subset demonstrated ongoing weaknesses in reading. Structural equation modeling results suggest that the double-deficit hypothesis is an accurate model for understanding adult reading achievement. Better reading achievement was associated with better phonological awareness and faster rapid automatized naming in adults. Posthoc analyses indicated that individuals with double deficits had significantly lower reading achievement than individuals with single deficits or no deficits.

  13. Tunguska, 1908: the gas pouch and soil fluidization hypothesis

    Science.gov (United States)

    Nistor, I.

    2012-01-01

    The Siberian taiga explosion of 30 June 1908 remains one of the great mysteries of the 20th century: millions of trees put down over an area of 2200 km2 without trace of a crater or meteorite fragments. Hundred years of failed searches have followed, resulting in as many flawed hypothesis which could not offer satisfactory explanations: meteorite, comet, UFO, etc. In the author's opinion, the cause is that the energy the explorers looked for was simply not there! The author's hypothesis is that a meteoroid encountered a gas pouch in the atmosphere, producing a devastating explosion, its effects being amplified by soil fluidization.

  14. Revisiting Hudson’s (1992) OO = O2 hypothesis

    DEFF Research Database (Denmark)

    Shibuya, Yoshikata; Jensen, Kim Ebensgaard

    2018-01-01

    In an important paper on the English “double-object”, or ditransitive, construction, Richard Hudson proposes a hypothesis that conflates the ditransitive direct object, or O2, and the monotransitive direct object, or OO, into the same syntactic functional category. While making important departures....... Applying simple collexeme analysis and multifactorial heatmap analysis to instances of OOs and O2s in ICE-GB, this paper shows that the usage-patterns of both are far too complex, displaying cross-register variation, for the OO = O2 hypothesis to be tenable. The findings provide support for a usage...

  15. The truncation of stellar discs : The magnetic hypothesis

    NARCIS (Netherlands)

    Battaner, E; Florido, E; Jimenez-Vicente, J

    We propose a hypothesis of the truncation of stellar discs based on the magnetic model of the rotation curve of spiral galaxies. Once the disc had formed and acquired its present structure, approximately, three balanced forces were acting on the initial gas: gravity and magnetic forces, inwards, and

  16. Developmental Dyslexia: The Visual Attention Span Deficit Hypothesis

    Science.gov (United States)

    Bosse, Marie-Line; Tainturier, Marie Josephe; Valdois, Sylviane

    2007-01-01

    The visual attention (VA) span is defined as the amount of distinct visual elements which can be processed in parallel in a multi-element array. Both recent empirical data and theoretical accounts suggest that a VA span deficit might contribute to developmental dyslexia, independently of a phonological disorder. In this study, this hypothesis was…

  17. Does the temporal mismatch hypothesis match in boreal populations?

    Science.gov (United States)

    Vatka, Emma; Rytkönen, Seppo; Orell, Markku

    2014-10-01

    The temporal mismatch hypothesis suggests that fitness is related to the degree of temporal synchrony between the energetic needs of the offspring and their food supply. The hypothesis has been a basis in studying the influence of climate warming on nature. This study enhances the knowledge on prevalence of temporal mismatches and their consequences in boreal populations, and questions the role of the temporal mismatch hypothesis as the principal explanation for the evolution of timing of breeding. To test this, we examined if synchrony with caterpillar prey or timing of breeding per se better explains reproductive output in North European parid populations. We compared responses of temperate-origin species, the great tit (Parus major) and the blue tit (Cyanistes caeruleus), and a boreal species, the willow tit (Poecile montanus). We found that phenologies of caterpillars and great tits, but not of blue tits, have advanced during the past decades. Phenologies correlated with spring temperatures that may function as cues about the timing of the food peak for great and blue tits. The breeding of great and blue tits and their caterpillar food remained synchronous. Synchrony explained breeding success better than timing of breeding alone. However, the synchrony effect arose only in certain conditions, such as with high caterpillar abundances or high breeding densities. Breeding before good synchrony seems advantageous at high latitudes, especially in the willow tit. Thus, the temporal mismatch hypothesis appears insufficient in explaining the evolution of timing of breeding.

  18. Planned Hypothesis Tests Are Not Necessarily Exempt from Multiplicity Adjustment

    Science.gov (United States)

    Frane, Andrew V.

    2015-01-01

    Scientific research often involves testing more than one hypothesis at a time, which can inflate the probability that a Type I error (false discovery) will occur. To prevent this Type I error inflation, adjustments can be made to the testing procedure that compensate for the number of tests. Yet many researchers believe that such adjustments are…

  19. Interactive comparison of hypothesis tests for statistical model checking

    NARCIS (Netherlands)

    de Boer, Pieter-Tjerk; Reijsbergen, D.P.; Scheinhardt, Willem R.W.

    2015-01-01

    We present a web-based interactive comparison of hypothesis tests as are used in statistical model checking, providing users and tool developers with more insight into their characteristics. Parameters can be modified easily and their influence is visualized in real time; an integrated simulation

  20. The estrogen hypothesis of schizophrenia implicates glucose metabolism

    DEFF Research Database (Denmark)

    Olsen, Line; Hansen, Thomas; Jakobsen, Klaus D

    2008-01-01

    implicated by the candidate genes resulting from the estrogen selection. We identified ten candidate genes using this approach that are all active in glucose metabolism and particularly in the glycolysis. Thus, we tested the hypothesis that variants of the glycolytic genes are associated with schizophrenia...

  1. Decision Environment and Heuristics in Individual and Collective Hypothesis Generation

    Science.gov (United States)

    2017-11-01

    making analysis . Organizational Behavior and Human Decision Processes, 69, 149-163. Mueller, S. T., & Piper, B. J. (2014). The Psychology...U.S. Army Research Institute for the Behavioral and Social Sciences Research Report 2013 Decision Environment...and Heuristics in Individual and Collective Hypothesis Generation Drew A. Leins Jim Leonard Laura A. Zimmerman Applied Research Associates

  2. The Lehman Sisters Hypothesis: an exploration of literature and bankers

    NARCIS (Netherlands)

    I.P. van Staveren (Irene)

    2012-01-01

    textabstractAbstract This article tests the Lehman Sisters Hypothesis in two complementary, although incomplete ways. It reviews the diverse empirical literature in behavioral, experimental, and neuroeconomics as well as related fields of behavioral research. And it presents the findings from an

  3. The Lehman Sisters Hypothesis: an exploration of literature and bankers

    NARCIS (Netherlands)

    I.P. van Staveren (Irene)

    2012-01-01

    textabstractThis article tests the Lehman Sisters Hypothesis in two complementary, although incomplete ways. It reviews the diverse empirical literature in behavioural, experimental, and neuroeconomics as well as related fields of behavioural research. And it presents the findings from an

  4. The Twin Deficits Hypothesis: An Empirical Analysis for Tanzania

    Directory of Open Access Journals (Sweden)

    Manamba Epaphra

    2017-09-01

    Full Text Available This paper examines the relationship between current account and government budget deficits in Tanzania. The paper tests the validity of the twin deficits hypothesis, using annual time series data for the 1966-2015 period. The paper is thought to be significant because the concept of the twin deficit hypothesis is fraught with controversy. Some researches support the hypothesis that there is a positive relationship between current account deficits and fiscal deficits in the economy while others do not. In this paper, the empirical tests fail to reject the twin deficits hypothesis, indicating that rising budget deficits put more strain on the current account deficits in Tanzania. Specifically, the Vector Error Correction Model results support the conventional theory of a positive relationship between fiscal and external balances, with a relatively high speed of adjustment toward the equilibrium position. This evidence is consistent with a small open economy. To address the problem that may result from this kind of relationship, appropriate policy variables for reducing budget deficits such as reduction in non-development expenditure, enhancement of domestic revenue collection and actively fight corruption and tax evasion should be adopted. The government should also target export oriented firms and encourage an import substitution industry by creating favorable business environments.

  5. Menarche and critical weight hypothesis revisted in Sagamu ...

    African Journals Online (AJOL)

    Using logistic regression correlation, while accounting for other variables, demonstrated stronger correlation between age at menarche and weight than menarche and height. Conclusion: Study demonstrated leveling off of menarche at between 13 and 14 years in our practice and agreed with hypothesis of critical weight of ...

  6. Rational Variability in Children's Causal Inferences: The Sampling Hypothesis

    Science.gov (United States)

    Denison, Stephanie; Bonawitz, Elizabeth; Gopnik, Alison; Griffiths, Thomas L.

    2013-01-01

    We present a proposal--"The Sampling Hypothesis"--suggesting that the variability in young children's responses may be part of a rational strategy for inductive inference. In particular, we argue that young learners may be randomly sampling from the set of possible hypotheses that explain the observed data, producing different hypotheses with…

  7. The catecholaminergic-cholinergic balance hypothesis of bipolar disorder revisited

    Science.gov (United States)

    van Enkhuizen, Jordy; Janowsky, David S; Olivier, Berend; Minassian, Arpi; Perry, William; Young, Jared W; Geyer, Mark A

    2014-01-01

    Bipolar disorder is a unique illness characterized by fluctuations between mood states of depression and mania. Originally, an adrenergic-cholinergic balance hypothesis was postulated to underlie these different affective states. In this review, we update this hypothesis with recent findings from human and animal studies, suggesting that a catecholaminergic-cholinergic hypothesis may be more relevant. Evidence from neuroimaging studies, neuropharmacological interventions, and genetic associations support the notion that increased cholinergic functioning underlies depression, whereas increased activations of the catecholamines (dopamine and norepinephrine) underlie mania. Elevated functional acetylcholine during depression may affect both muscarinic and nicotinic acetylcholine receptors in a compensatory fashion. Increased functional dopamine and norepinephrine during mania on the other hand may affect receptor expression and functioning of dopamine reuptake transporters. Despite increasing evidence supporting this hypothesis, a relationship between these two neurotransmitter systems that could explain cycling between states of depression and mania is missing. Future studies should focus on the influence of environmental stimuli and genetic susceptibilities that may affect the catecholaminergic-cholinergic balance underlying cycling between the affective states. Overall, observations from recent studies add important data to this revised balance theory of bipolar disorder, renewing interest in this field of research. PMID:25107282

  8. Why chronic wounds will not heal: a novel hypothesis

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Kirketerp-Moller, K.; Jensen, P.O.

    2008-01-01

    The present paper presents a hypothesis aimed at explaining why venous leg ulcers, pressure ulcers, and diabetic foot ulcers develop into a chronic state. We propose that the lack of proper wound healing is at least in part caused by inefficient eradication of infecting, opportunistic pathogens...

  9. Tax Evasion, Information Reporting, and the Regressive Bias Hypothesis

    DEFF Research Database (Denmark)

    Boserup, Simon Halphen; Pinje, Jori Veng

    A robust prediction from the tax evasion literature is that optimal auditing induces a regressive bias in effective tax rates compared to statutory rates. If correct, this will have important distributional consequences. Nevertheless, the regressive bias hypothesis has never been tested empirically...

  10. Does Effeciency Wage Hypothesis Hold in Tanzanian Labour Market?

    African Journals Online (AJOL)

    The primary objective of this paper is to test the hypothesis of efficiency wage in the context of Tanzania labour market. The test is facilitated via estimating the correlation between firm level productivity and firm level weighted average wage in Tanzania manufacturing enterprises. The study uses panel dimension of the data ...

  11. Hypothesis, Prediction, and Conclusion: Using Nature of Science Terminology Correctly

    Science.gov (United States)

    Eastwell, Peter

    2012-01-01

    This paper defines the terms "hypothesis," "prediction," and "conclusion" and shows how to use the terms correctly in scientific investigations in both the school and science education research contexts. The scientific method, or hypothetico-deductive (HD) approach, is described and it is argued that an understanding of the scientific method,…

  12. A test of the reward-value hypothesis.

    Science.gov (United States)

    Smith, Alexandra E; Dalecki, Stefan J; Crystal, Jonathon D

    2017-03-01

    Rats retain source memory (memory for the origin of information) over a retention interval of at least 1 week, whereas their spatial working memory (radial maze locations) decays within approximately 1 day. We have argued that different forgetting functions dissociate memory systems. However, the two tasks, in our previous work, used different reward values. The source memory task used multiple pellets of a preferred food flavor (chocolate), whereas the spatial working memory task provided access to a single pellet of standard chow-flavored food at each location. Thus, according to the reward-value hypothesis, enhanced performance in the source memory task stems from enhanced encoding/memory of a preferred reward. We tested the reward-value hypothesis by using a standard 8-arm radial maze task to compare spatial working memory accuracy of rats rewarded with either multiple chocolate or chow pellets at each location using a between-subjects design. The reward-value hypothesis predicts superior accuracy for high-valued rewards. We documented equivalent spatial memory accuracy for high- and low-value rewards. Importantly, a 24-h retention interval produced equivalent spatial working memory accuracy for both flavors. These data are inconsistent with the reward-value hypothesis and suggest that reward value does not explain our earlier findings that source memory survives unusually long retention intervals.

  13. Semiparametric Power Envelopes for Tests of the Unit Root Hypothesis

    DEFF Research Database (Denmark)

    Jansson, Michael

    This paper derives asymptotic power envelopes for tests of the unit root hypothesis in a zero-mean AR(1) model. The power envelopes are derived using the limits of experiments approach and are semiparametric in the sense that the underlying error distribution is treated as an unknown...

  14. The "Discouraged-Business-Major" Hypothesis: Policy Implications

    Science.gov (United States)

    Marangos, John

    2012-01-01

    This paper uses a relatively large dataset of the stated academic major preferences of economics majors at a relatively large, not highly selective, public university in the USA to identify the "discouraged-business-majors" (DBMs). The DBM hypothesis addresses the phenomenon where students who are screened out of the business curriculum often…

  15. A test for diffusional coherency strain hypothesis in the ...

    Indian Academy of Sciences (India)

    boundary in the case of diffusion induced grain boundary migration (DIGM) and liquid film migration (LFM). In the present work, the validity of diffusional coherency strain hypothesis is verified in Mg–Al alloy, which exhibits discontinuous precipitation. Samples were tested with an applied stress simultaneously with disconti-.

  16. A re-examination of the exchange rate overshooting hypothesis

    African Journals Online (AJOL)

    kirstam

    employed the ARDL model, which allows for variables of different integration orders to be examined in the same ... determined rate following the introduction of the broad-based interbank foreign exchange rate system in Zambia ... overshooting hypothesis for Taiwan and Turkey, respectively. This study should fill the gap in ...

  17. The Purchasing Power Parity Hypothesis: Is there evidence from the ...

    African Journals Online (AJOL)

    The hypothesis that national price levels should be equal when expressed in a common currency has been widely studied. However, evidence from empirical literature is mixed on the validity of purchasing power parity (PPP) in the long run. This paper examined the long run validity of PPP using the bilateral real exchange ...

  18. ON THE REJECTION ABILITY REQUIRED IN MULTIPLE HYPOTHESIS TECHNIQUES

    NARCIS (Netherlands)

    Sako, H.; Kagehiro, T.; Fujisawa, H.

    2004-01-01

    The so­called multiple hypothesis technique is applied to solve a recognition problem that can be divided into at least two sub­problems. The principle of the technique is to solve the sub­problems by recognisers, a pre­recogniser and a post­recogniser, and to allow the pre­recogniser to leave

  19. Fecundity of trees and the colonization-competition hypothesis

    Science.gov (United States)

    James S. Clark; Shannon LaDeau; Ines Ibanez

    2004-01-01

    Colonization-competition trade-offs represent a stabilizing mechanism that is thought to maintain diversity of forest trees. If so, then early-successional species should benefit from high capacity to colonize new sites, and late-successional species should be good competitors. Tests of this hypothesis in forests have been precluded by an inability to estimate...

  20. Random Effects Structure for Confirmatory Hypothesis Testing: Keep It Maximal

    Science.gov (United States)

    Barr, Dale J.; Levy, Roger; Scheepers, Christoph; Tily, Harry J.

    2013-01-01

    Linear mixed-effects models (LMEMs) have become increasingly prominent in psycholinguistics and related areas. However, many researchers do not seem to appreciate how random effects structures affect the generalizability of an analysis. Here, we argue that researchers using LMEMs for confirmatory hypothesis testing should minimally adhere to the…

  1. THE BARKER HYPOTHESIS: IMPLICATIONS FOR FUTURE DIRECTIONS IN TOXICOLOGY RESEARCH

    Science.gov (United States)

    This review covers the past year’s papers germane to the Barker hypothesis. While much of the literature has centered on maternal and developmental nutrition, new findings have emerged on the ability of toxic exposures during development to impact fetal/developmental programming....

  2. Simultaneity modeling analysis of the environmental Kuznets curve hypothesis

    International Nuclear Information System (INIS)

    Ben Youssef, Adel; Hammoudeh, Shawkat; Omri, Anis

    2016-01-01

    The environmental Kuznets curve (EKC) hypothesis has been recognized in the environmental economics literature since the 1990's. Various statistical tests have been used on time series, cross section and panel data related to single and groups of countries to validate this hypothesis. In the literature, the validation has always been conducted by using a single equation. However, since both the environment and income variables are endogenous, the estimation of a single equation model when simultaneity exists produces inconsistent and biased estimates. Therefore, we formulate simultaneous two-equation models to investigate the EKC hypothesis for fifty-six countries, using annual panel data from 1990 to 2012, with the end year is determined by data availability for the panel. To make the panel data analysis more homogeneous, we investigate this issue for a three income-based panels (namely, high-, middle-, and low-income panels) given several explanatory variables. Our results indicate that there exists a bidirectional causality between economic growth and pollution emissions in the overall panels. We also find that the relationship is nonlinear and has an inverted U-shape for all the considered panels. Policy implications are provided. - Highlights: • We have given a new look for the validity of the EKC hypothesis. • We formulate two-simultaneous equation models to validate this hypothesis for fifty-six countries. • We find a bidirectional causality between economic growth and pollution emissions. • We also discover an inverted U-shaped between environmental degradation and economic growth. • This relationship varies at different stages of economic development.

  3. A critique of statistical hypothesis testing in clinical research

    Directory of Open Access Journals (Sweden)

    Somik Raha

    2011-01-01

    Full Text Available Many have documented the difficulty of using the current paradigm of Randomized Controlled Trials (RCTs to test and validate the effectiveness of alternative medical systems such as Ayurveda. This paper critiques the applicability of RCTs for all clinical knowledge-seeking endeavors, of which Ayurveda research is a part. This is done by examining statistical hypothesis testing, the underlying foundation of RCTs, from a practical and philosophical perspective. In the philosophical critique, the two main worldviews of probability are that of the Bayesian and the frequentist. The frequentist worldview is a special case of the Bayesian worldview requiring the unrealistic assumptions of knowing nothing about the universe and believing that all observations are unrelated to each other. Many have claimed that the first belief is necessary for science, and this claim is debunked by comparing variations in learning with different prior beliefs. Moving beyond the Bayesian and frequentist worldviews, the notion of hypothesis testing itself is challenged on the grounds that a hypothesis is an unclear distinction, and assigning a probability on an unclear distinction is an exercise that does not lead to clarity of action. This critique is of the theory itself and not any particular application of statistical hypothesis testing. A decision-making frame is proposed as a way of both addressing this critique and transcending ideological debates on probability. An example of a Bayesian decision-making approach is shown as an alternative to statistical hypothesis testing, utilizing data from a past clinical trial that studied the effect of Aspirin on heart attacks in a sample population of doctors. As a big reason for the prevalence of RCTs in academia is legislation requiring it, the ethics of legislating the use of statistical methods for clinical research is also examined.

  4. Mechanisms of eyewitness suggestibility: tests of the explanatory role hypothesis.

    Science.gov (United States)

    Rindal, Eric J; Chrobak, Quin M; Zaragoza, Maria S; Weihing, Caitlin A

    2017-10-01

    In a recent paper, Chrobak and Zaragoza (Journal of Experimental Psychology: General, 142(3), 827-844, 2013) proposed the explanatory role hypothesis, which posits that the likelihood of developing false memories for post-event suggestions is a function of the explanatory function the suggestion serves. In support of this hypothesis, they provided evidence that participant-witnesses were especially likely to develop false memories for their forced fabrications when their fabrications helped to explain outcomes they had witnessed. In three experiments, we test the generality of the explanatory role hypothesis as a mechanism of eyewitness suggestibility by assessing whether this hypothesis can predict suggestibility errors in (a) situations where the post-event suggestions are provided by the experimenter (as opposed to fabricated by the participant), and (b) across a variety of memory measures and measures of recollective experience. In support of the explanatory role hypothesis, participants were more likely to subsequently freely report (E1) and recollect the suggestions as part of the witnessed event (E2, source test) when the post-event suggestion helped to provide a causal explanation for a witnessed outcome than when it did not serve this explanatory role. Participants were also less likely to recollect the suggestions as part of the witnessed event (on measures of subjective experience) when their explanatory strength had been reduced by the presence of an alternative explanation that could explain the same outcome (E3, source test + warning). Collectively, the results provide strong evidence that the search for explanatory coherence influences people's tendency to misremember witnessing events that were only suggested to them.

  5. The Effectiveness of the Comprehension Hypothesis: A Review on the Current Research on Incidental Vocabulary Acquisition

    Science.gov (United States)

    Ponniah, Joseph

    2011-01-01

    The Comprehension Hypothesis (CH) is the most powerful hypothesis in the field of Second Language Acquisition despite the presence of the rivals the skill-building hypothesis, the output hypothesis, and the interaction hypothesis. The competing hypotheses state that consciously learned linguistic knowledge is a necessary step for the development…

  6. Experimental investigation of the streaming potential hypothesis for ionic polymer transducers in sensing

    International Nuclear Information System (INIS)

    Kocer, Bilge; Weiland, Lisa Mauck

    2013-01-01

    Ionic polymer transducers (IPTs) are ionomers that are plated with conductive media such as metals, leading to capacitive behavior. IPTs exhibit bending deformation when a voltage difference is applied across the surfaces of the transducer, thus displaying actuation. A current is generated when they are deformed, thus exhibiting sensing. However, the mechanisms responsible for actuation and sensing differ; research to date has focused predominantly on actuation, while identification of the dominant mechanism responsible for IPT sensing remains an open topic. The goal of this work is to initiate experimental investigations of the streaming potential hypothesis for IPT sensing. This hypothesis argues that the presence of unbound counter-ions within the hydrophilic phase of an ionic polymer behaves as an electrolyte in the presence of the electrode. Thus, as per classic streaming potential analyses, relative motion of the electrolyte with respect to the electrode will result in the evolution of a streaming potential. According to this hypothesis, the extent of communication between the electrode and electrolyte becomes important in the evolution of an electrical signal. This study experimentally explores the effect of electrode architecture on the sensing response where the IPTs are prepared via the direct assembly process (DAP). The DAP is selected because it enables control over the fabrication of the electrode structure. In this study, cantilevered IPT samples having different electrode composition are tested under several step input tip displacements. The experimental outcomes are consistent with predicted trends via streaming potential theory. (paper)

  7. The physical constants as biosignature: an anthropic retrodiction of the Selfish Biocosm Hypothesis

    Science.gov (United States)

    Gardner, James N.

    2004-07-01

    Goal 7 of the NASA Astrobiology Roadmap states: "Determine how to recognize signatures of life on other worlds and on early Earth. Identify biosignatures that can reveal and characterize past or present life in ancient samples from Earth, extraterrestrial samples measured in situ, samples returned to Earth, remotely measured planetary atmospheres and surfaces, and other cosmic phenomena." The cryptic reference to "other cosmic phenomena" would appear to be broad enough to include the possible identification of biosignatures embedded in the dimensionless constants of physics. The existence of such a set of biosignatures - a life-friendly suite of physical constants - is a retrodiction of the Selfish Biocosm (SB) hypothesis. This hypothesis offers an alternative to the weak anthropic explanation of our indisputably life-friendly cosmos favoured by (1) an emerging alliance of M-theory-inspired cosmologists and advocates of eternal inflation like Linde and Weinberg, and (2) supporters of the quantum theory-inspired sum-over-histories cosmological model offered by Hartle and Hawking. According to the SB hypothesis, the laws and constants of physics function as the cosmic equivalent of DNA, guiding a cosmologically extended evolutionary process and providing a blueprint for the replication of new life-friendly progeny universes.

  8. A robust null hypothesis for the potential causes of megadrought in western North America

    Science.gov (United States)

    Ault, T.; St George, S.; Smerdon, J. E.; Coats, S.; Mankin, J. S.; Cruz, C. C.; Cook, B.; Stevenson, S.

    2017-12-01

    The western United States was affected by several megadroughts during the last 1200 years, most prominently during the Medieval Climate Anomaly (MCA: 800 to 1300 CE). A null hypothesis is developed to test the possibility that, given a sufficiently long period of time, these events are inevitable and occur purely as a consequence of internal climate variability. The null distribution of this hypothesis is populated by a linear inverse model (LIM) constructed from global sea-surface temperature anomalies and self-calibrated Palmer Drought Severity Index data for North America. Despite being trained only on seasonal data from the late 20th century, the LIM produces megadroughts that are comparable in their duration, spatial scale, and magnitude as the most severe events of the last 12 centuries. The null hypothesis therefore cannot be rejected with much confidence when considering these features of megadrought, meaning that similar events are possible today, even without any changes to boundary conditions. In contrast, the observed clustering of megadroughts in the MCA, as well as the change in mean hydroclimate between the MCA and the 1500-2000 period, are more likely to have been caused by either external forcing or by internal climate variability not well sampled during the latter half of the Twentieth Century. Finally, the results demonstrate the LIM is a viable tool for determining whether paleoclimate reconstructions events should be ascribed to external forcings, "out of sample" climate mechanisms, or if they are consistent with the variability observed during the recent period.

  9. ON THE COMPOUND INFLECTIONS MADE WITH VERB “TO BE” AND THEIR USES IN TURKEY TURKISH ACCENTS “ol- ” FİİLİ İLE YAPILAN BİRLEŞİK ÇEKİMLER VE TÜRKİYE TÜRKÇESİ AĞIZLARINDAKİ KULLANIMI ÜZERİNE

    Directory of Open Access Journals (Sweden)

    Özgür AY

    2011-01-01

    Full Text Available It is utmost important to re-examine the inflections of the tenses and modals in Turkish and to develop tables on which these inflections are categorized in detail in order both to overcome the hardships faced during the teaching of Turkish as the mother language and to eliminate the errors in the field. The compound inflections used in Turkey Turkish have been reviewed by G. Gülsevin in his article titled “On the Compound Inflections of Tenses and Modals in Turkey Turkish”. In this article, I have tried to study the uses and the prevalence of the compound inflections made with “to be” verb in the accents of Turkey Turkish, one of the topics G. Gülsevin has covered in his article. Türkiye Türkçesindeki fiil zaman ve kip çekimlerinin yeniden incelenmesi ve ayrıntılı sınıflandırmaların bulunduğu tabloların geliştirilmesi, hem Türkçenin ana dili olarak öğretiminde çıkan zorlukların aşılması için hem de içine düşülen yanlışlıkların ortadan kaldırılması için son derece önemlidir. Türkiye Türkçesinde fiil ve kip çekimlerinde kullanılan birleşik yapılar G. Gülsevin’in “Türkiye Türkçesindeki Zaman ve Kip Çekimlerinde Birleşik Yapılar Üzerine” başlıklı bildirisinde ayrıntıları ile değerlendirilmiştir. Bu yazıda, o bildiride öne sürülen tespitlerden biri olan “ol-” fiili ile yapılan birleşik çekimlerin, Türkiye Türkçesi ağızlarındaki kullanımı ve yaygınlığı değerlendirilmeye çalışılmıştır.

  10. Formation of Pluto's moons: the fission hypothesis revisited

    Science.gov (United States)

    Prentice, A. J.

    2015-12-01

    I re-examine the fission hypothesis for the formation of Pluto's moons within the framework of a gas ring model for the origin of the solar system (Prentice 1978 Moon Planets 19 341; 2015 LPSC, abs. 2664). It is supposed that the planetary system condensed from a concentric family of orbiting gas rings. These were cast off by the proto-solar cloud (PSC) as a means for disposing of excess spin angular momentum during gravitational contraction. If contraction is homologous, the mean orbital radii R(n) (n = 0,1,2,3,..) of the rings form a nearly geometric sequence. The temperatures T(n) of the rings scale roughly as T(n) = A/R(n) and the gas pressures p(n) on the gas ring mean orbits scale as p(n) = B/R(n)^4. The constants A & B are chosen so that (1) the geometric mean of the ratio R(n+1)/R(n) of successive gas ring radii from Jupiter to Mercury matches the observed mean ratio of planetary distances and (2) that the metal mass fraction at Mercury's orbit, namely 0.70, yields a planet whose mean density equals the observed value (Prentice 2008, LPSC abs. 1945.pdf). I assume that proto-Pluto (PPO) condensed within the n = 0 gas ring shed by the PSC at the orbit of Quaoar (43.2 AU). Here T(0) = 26.3 K and p(0) = 1.3 x 10^(-9) bar. The condensate consists of anhydrous rock (mass fraction 0.5255), graphite (0.0163), water ice (0.1858), dry ice (0.2211), and methane ice (0.0513). The RTP rock density is 3.662 g/cc. I assume that melting of the ices in the PPO took place through the decay of short-lived radioactive nuclides, causing internal segregation of rock & graphite. If rotational fission did occur and Pluto's moons formed from ejected liquid water and CO2, we get a Charon mean density of 1.24 g/cc. This is much lower than the observed value. Perhaps some of the rock and graphite became entrained in the fissioned liquid, so yielding a dense core for Charon of mass fraction ~0.4? In any event, the surfaces of all of the moons should have initially been football

  11. Incremental balloon deflation following complete resuscitative endovascular balloon occlusion of the aorta results in steep inflection of flow and rapid reperfusion in a large animal model of hemorrhagic shock.

    Science.gov (United States)

    Davidson, Anders J; Russo, Rachel M; Ferencz, Sarah-Ashley E; Cannon, Jeremy W; Rasmussen, Todd E; Neff, Lucas P; Johnson, M Austin; Williams, Timothy K

    2017-07-01

    To avoid potential cardiovascular collapse after resuscitative endovascular balloon occlusion of the aorta (REBOA), current guidelines recommend methodically deflating the balloon for 5 minutes to gradually reperfuse distal tissue beds. However, anecdotal evidence suggests that this approach may still result in unpredictable aortic flow rates and hemodynamic instability. We sought to characterize aortic flow dynamics following REBOA as the balloon is deflated in accordance with current practice guidelines. Eight Yorkshire-cross swine were splenectomized, instrumented, and subjected to rapid 25% total blood volume hemorrhage. After 30 minutes of shock, animals received 60 minutes of Zone 1 REBOA with a low-profile REBOA catheter. During subsequent resuscitation with shed blood, the aortic occlusion balloon was gradually deflated in stepwise fashion at the rate of 0.5 mL every 30 seconds until completely deflated. Aortic flow rate and proximal mean arterial pressure (MAP) were measured continuously over the period of balloon deflation. Graded balloon deflation resulted in variable initial return of aortic flow (median, 78 seconds; interquartile range [IQR], 68-105 seconds). A rapid increase in aortic flow during a single-balloon deflation step was observed in all animals (median, 819 mL/min; IQR, 664-1241 mL/min) and corresponded with an immediate decrease in proximal MAP (median, 30 mm Hg; IQR, 14.5-37 mm Hg). Total balloon volume and time to return of flow demonstrated no correlation (r = 0.016). This study is the first to characterize aortic flow during balloon deflation following REBOA. A steep inflection point occurs during balloon deflation that results in an abrupt increase in aortic flow and a concomitant decrease in MAP. Furthermore, the onset of distal aortic flow was inconsistent across study animals and did not correlate with initial balloon volume or relative deflation volume. Future studies to define the factors that affect aortic flow during balloon

  12. Prospective detection of large prediction errors: a hypothesis testing approach

    International Nuclear Information System (INIS)

    Ruan, Dan

    2010-01-01

    Real-time motion management is important in radiotherapy. In addition to effective monitoring schemes, prediction is required to compensate for system latency, so that treatment can be synchronized with tumor motion. However, it is difficult to predict tumor motion at all times, and it is critical to determine when large prediction errors may occur. Such information can be used to pause the treatment beam or adjust monitoring/prediction schemes. In this study, we propose a hypothesis testing approach for detecting instants corresponding to potentially large prediction errors in real time. We treat the future tumor location as a random variable, and obtain its empirical probability distribution with the kernel density estimation-based method. Under the null hypothesis, the model probability is assumed to be a concentrated Gaussian centered at the prediction output. Under the alternative hypothesis, the model distribution is assumed to be non-informative uniform, which reflects the situation that the future position cannot be inferred reliably. We derive the likelihood ratio test (LRT) for this hypothesis testing problem and show that with the method of moments for estimating the null hypothesis Gaussian parameters, the LRT reduces to a simple test on the empirical variance of the predictive random variable. This conforms to the intuition to expect a (potentially) large prediction error when the estimate is associated with high uncertainty, and to expect an accurate prediction when the uncertainty level is low. We tested the proposed method on patient-derived respiratory traces. The 'ground-truth' prediction error was evaluated by comparing the prediction values with retrospective observations, and the large prediction regions were subsequently delineated by thresholding the prediction errors. The receiver operating characteristic curve was used to describe the performance of the proposed hypothesis testing method. Clinical implication was represented by miss

  13. Universal phase and force diagrams for a microbubble or pendant drop in static fluid on a surface

    Science.gov (United States)

    Wei, P. S.; Hsiao, C. C.; Chen, K. Y.

    2008-01-01

    Dimensionless three-dimensional universal phase and lift force diagrams of a microbubble (or pendant drop) in static liquid on a solid surface (or orifice) are presented in this work. Microbubble dynamics has been found to play a vital role in mass, momentum, energy, and concentration transfer rates in contemporary micro- and nanosciences and technologies. In this study, dimensionless phase and force diagrams are introduced by utilizing the analytical solutions of the microbubble shape reported in the literature. It shows that phase and force diagrams can be universally specified by two dimensionless independent parameters, Bond number, and contact angle (or base radius). Based on the presence of an inflection point or neck on the microbubble surface, each diagram exhibits three regions. Growth, detachment, and entrapment of a microbubble can be described by path lines in three regions. The corresponding universal total lift forces include hydrostatic buoyancy, difference in gas, and hydrostatic pressures at the base, capillary pressure, as well as surface tension induced by the variation of circumference, which has not been treated in the literature so far. In the absence of viscous stress and Marangoni force, the total lift force equals surface tension induced by the variation of circumference. The latter can be an attaching or lifting force, depending on whether the state in the distinct regions and contact angle is less than or greater than a critical angle. The critical angle, which is slightly less than the inclination angle at the inflection point, is decreased with increasing Bond number.

  14. Teen Fertility and Gender Inequality in Education: A Contextual Hypothesis

    Directory of Open Access Journals (Sweden)

    C. Shannon Stokes

    2004-12-01

    Full Text Available Previous studies in developed countries have found a micro-level association between teenage fertility and girls' educational attainment but researchers still debate the policy implications of these associations. First, are these associations causal? Second, are they substantively important enough, at the macro-level, to warrant policy attention? In other words, how much would policy efforts to reduce unintended pregnancy among teens pay off in terms of narrowing national gender gaps in educational attainment? Third, under what contexts are these payoffs likely to be important? This paper focuses on the latter two questions. We begin by proposing a contextual hypothesis to explain cross-national variation in the gender-equity payoffs from reducing unintended teen fertility. We then test this hypothesis, using DHS data from 38 countries.

  15. The Riemann hypothesis illuminated by the Newton flow of ζ

    International Nuclear Information System (INIS)

    Neuberger, J W; Feiler, C; Maier, H; Schleich, W P

    2015-01-01

    We analyze the Newton flow of the Riemann zeta function ζ and rederive in an elementary way the Riemann–von Mangoldt estimate of the number of non-trivial zeros below a given imaginary part. The representation of the flow on the Riemann sphere highlights the importance of the North pole as the starting and turning point of the separatrices, that is of the continental divides of the Newton flow. We argue that the resulting patterns may lead to deeper insight into the Riemann hypothesis. For this purpose we also compare and contrast the Newton flow of ζ with that of a function which in many ways is similar to ζ, but violates the Riemann hypothesis. (invited comment)

  16. A hypothesis on chemical mechanism of the effect of hydrogen

    Directory of Open Access Journals (Sweden)

    Shi Penghui

    2012-06-01

    Full Text Available Abstract Many studies have shown that hydrogen can play important roles on the antioxidant, anti-inflammatory and other protective effects. Ohsawa et al have proved that hydrogen can electively and directly scavenge hydroxyl radical. But this mechanism cannot explain more new experimental results. In this article, the hypothesis, which is inspired by H2 could bind to the metal as a ligand, come up to explain its extensive biology effect: Hydrogen could regulate particular metalloproteins by bonding (M–H2 interaction it. And then it could affect the metabolization of ROS and signal transduction. Metalloproteins may be ones of the target molecules of H2 action. Metal ions may be appropriate role sites for H2 molecules. The hypothesis pointed out a new direction to clarify its mechanisms.

  17. Hyman Minsky's financial instability hypothesis and the Greek debt crisis

    Directory of Open Access Journals (Sweden)

    Sergey Beshenov

    2015-12-01

    Full Text Available This article attempts to analyze the current debt crisis in Greece based on the financial instability hypothesis developed by Hyman Minsky. This article shows that the hypothesis provides an understanding of how an economy endogenously becomes “financially fragile” and thus prone to crises. The authors analyze how public and private sector behavior in the Greek economy led to the country's debt crisis. In particular, based on a sample of 36 Greek companies, the authors show that between 2001 and 2014, the majority of those companies had switched to fragile financial structures. Special attention is devoted to the negative consequences of applying the neoclassical doctrine of “austerity measures” in Greece as the principal “anti-crisis” concept of mainstream economic science.

  18. A Unifying Hypothesis for Familial and Sporadic Alzheimer's Disease

    Directory of Open Access Journals (Sweden)

    Carole J. Proctor

    2012-01-01

    Full Text Available Alzheimer's disease (AD is characterised by the aggregation of two quite different proteins, namely, amyloid-beta (Aβ, which forms extracellular plaques, and tau, the main component of cytoplasmic neurofibrillary tangles. The amyloid hypothesis proposes that Aβ plaques precede tangle formation but there is still much controversy concerning the order of events and the linkage between Aβ and tau alterations is still unknown. Mathematical modelling has become an essential tool for generating and evaluating hypotheses involving complex systems. We have therefore used this approach to discover the most probable pathway linking Aβ and tau. The model supports a complex pathway linking Aβ and tau via GSK3β, p53, and oxidative stress. Importantly, the pathway contains a cycle with multiple points of entry. It is this property of the pathway which enables the model to be consistent with both the amyloid hypothesis for familial AD and a more complex pathway for sporadic forms.

  19. The hormonal sensitivity hypothesis: A review and new findings.

    Science.gov (United States)

    Pope, Carley J; Oinonen, Kirsten; Mazmanian, Dwight; Stone, Suzanne

    2017-05-01

    Previous women's health practitioners and researchers have postulated that some women are particularly sensitive to hormonal changes occurring during reproductive events. We hypothesize that some women are particularly sensitive to hormonal changes occurring across their reproductive lifespan. To evaluate this hypothesis, we reviewed findings from the existing literature and findings from our own lab. Taken together, the evidence we present shows a recurring pattern of hormonal sensitivity at predictable but different times across the lifespan of some women (i.e., menarche, the premenstrual phase, hormonal contraceptive use, pregnancy, the postpartum period, and menopause). These findings provide support for the hypothesis that there is a subgroup of women who are more susceptible to physical, psychological, and sexual symptoms related to hormonal shifts or abrupt hormonal fluctuations that occur throughout the reproductive lifespan. We propose that this pattern reflects a Hormonal Sensitivity Syndrome. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. The hubris hypothesis: The downside of comparative optimism displays.

    Science.gov (United States)

    Hoorens, Vera; Van Damme, Carolien; Helweg-Larsen, Marie; Sedikides, Constantine

    2017-04-01

    According to the hubris hypothesis, observers respond more unfavorably to individuals who express their positive self-views comparatively than to those who express their positive self-views non-comparatively, because observers infer that the former hold a more disparaging view of others and particularly of observers. Two experiments extended the hubris hypothesis in the domain of optimism. Observers attributed less warmth (but not less competence) to, and showed less interest in affiliating with, an individual displaying comparative optimism (the belief that one's future will be better than others' future) than with an individual displaying absolute optimism (the belief that one's future will be good). Observers responded differently to individuals displaying comparative versus absolute optimism, because they inferred that the former held a gloomier view of the observers' future. Consistent with previous research, observers still attributed more positive traits to a comparative or absolute optimist than to a comparative or absolute pessimist. Copyright © 2016. Published by Elsevier Inc.

  1. The patriarch hypothesis : An alternative explanation of menopause.

    Science.gov (United States)

    Marlowe, F

    2000-03-01

    Menopause is puzzling because life-history theory predicts there should be no selection for outliving one's reproductive capacity. Adaptive explanations of menopause offered thus far turn on women's long-term investment in offspring and grandoffspring, all variations on the grandmother hypothesis. Here, I offer a very different explanation. The patriarch hypothesis proposes that once males became capable of maintaining high status and reproductive access beyond their peak physical condition, selection favored the extension of maximum life span in males. Because the relevant genes were not on the Y chromosome, life span increased in females as well. However, the female reproductive span was constrained by the depletion of viable oocytes, which resulted in menopause.

  2. Amyloid cascade hypothesis: Pathogenesis and therapeutic strategies in Alzheimer's disease.

    Science.gov (United States)

    Barage, Sagar H; Sonawane, Kailas D

    2015-08-01

    Alzheimer's disease is an irreversible, progressive neurodegenerative disorder. Various therapeutic approaches are being used to improve the cholinergic neurotransmission, but their role in AD pathogenesis is still unknown. Although, an increase in tau protein concentration in CSF has been described in AD, but several issues remains unclear. Extensive and accurate analysis of CSF could be helpful to define presence of tau proteins in physiological conditions, or released during the progression of neurodegenerative disease. The amyloid cascade hypothesis postulates that the neurodegeneration in AD caused by abnormal accumulation of amyloid beta (Aβ) plaques in various areas of the brain. The amyloid hypothesis has continued to gain support over the last two decades, particularly from genetic studies. Therefore, current research progress in several areas of therapies shall provide an effective treatment to cure this devastating disease. This review critically evaluates general biochemical and physiological functions of Aβ directed therapeutics and their relevance. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. A test of the domain-specific acculturation strategy hypothesis.

    Science.gov (United States)

    Miller, Matthew J; Yang, Minji; Lim, Robert H; Hui, Kayi; Choi, Na-Yeun; Fan, Xiaoyan; Lin, Li-Ling; Grome, Rebekah E; Farrell, Jerome A; Blackmon, Sha'kema

    2013-01-01

    Acculturation literature has evolved over the past several decades and has highlighted the dynamic ways in which individuals negotiate experiences in multiple cultural contexts. The present study extends this literature by testing M. J. Miller and R. H. Lim's (2010) domain-specific acculturation strategy hypothesis-that individuals might use different acculturation strategies (i.e., assimilated, bicultural, separated, and marginalized strategies; J. W. Berry, 2003) across behavioral and values domains-in 3 independent cluster analyses with Asian American participants. Present findings supported the domain-specific acculturation strategy hypothesis as 67% to 72% of participants from 3 independent samples using different strategies across behavioral and values domains. Consistent with theory, a number of acculturation strategy cluster group differences emerged across generational status, acculturative stress, mental health symptoms, and attitudes toward seeking professional psychological help. Study limitations and future directions for research are discussed.

  4. KESEMPATAN BERTUMBUH DAN MANAJEMEN LABA: UJI POLITICAL COST HYPOTHESIS

    Directory of Open Access Journals (Sweden)

    R. Anastasia Endang Susilawati

    2010-02-01

    Full Text Available In this paper, we test political cost hypothesis in Indonesian market. Political cost hypothesis said that some firms that are more vulnerable to political cost than the others manage income downward to avoiding the attention of government and regulator. In this context we evaluate firms with high investment opportunity set (IOS. Firm with high IOS faces more political cost than firm with low IOS. So it is hypotesized that they will be lowering income to minimize the political cost, like increasing demand of labor union, government intrusion, antitrust regulator and the other. Consistent with previous study, we find that firm with high investment opportunity set manage accrual downward to counter the potential government intrusions and to reduce the political cost.

  5. Discrete causal theory emergent spacetime and the causal metric hypothesis

    CERN Document Server

    Dribus, Benjamin F

    2017-01-01

    This book evaluates and suggests potentially critical improvements to causal set theory, one of the best-motivated approaches to the outstanding problems of fundamental physics. Spacetime structure is of central importance to physics beyond general relativity and the standard model. The causal metric hypothesis treats causal relations as the basis of this structure. The book develops the consequences of this hypothesis under the assumption of a fundamental scale, with smooth spacetime geometry viewed as emergent. This approach resembles causal set theory, but differs in important ways; for example, the relative viewpoint, emphasizing relations between pairs of events, and relationships between pairs of histories, is central. The book culminates in a dynamical law for quantum spacetime, derived via generalized path summation.

  6. The linear model and hypothesis a general unifying theory

    CERN Document Server

    Seber, George

    2015-01-01

    This book provides a concise and integrated overview of hypothesis testing in four important subject areas, namely linear and nonlinear models, multivariate analysis, and large sample theory. The approach used is a geometrical one based on the concept of projections and their associated idempotent matrices, thus largely avoiding the need to involve matrix ranks. It is shown that all the hypotheses encountered are either linear or asymptotically linear, and that all the underlying models used are either exactly or asymptotically linear normal models. This equivalence can be used, for example, to extend the concept of orthogonality in the analysis of variance to other models, and to show that the asymptotic equivalence of the likelihood ratio, Wald, and Score (Lagrange Multiplier) hypothesis tests generally applies.

  7. The Literal Translation Hypothesis in ESP Teaching/Learning Environments

    Directory of Open Access Journals (Sweden)

    Pedro A. Fuertes-Olivera

    2015-11-01

    Full Text Available Research on the characteristics of specialized vocabulary usually replicates studies that deal with general words, e.g. they typically describe frequent terms and focus on their linguistic characteristics to aid in the learning and acquisition of the terms. We dispute this practise, as we believe that the basic characteristic of terms is that they are coined to restrict meaning, i.e. to be as precise and as specific as possible in a particular context. For instance, around 70% of English and Spanish accounting terms are multi-word terms, most of which contain more than three orthographic words that syntactically behave in a way that is very different from the syntactic behaviour of the node on which they are formed (Fuertes-Olivera and Tarp, forthcoming. This has prompted us to propose a research framework that investigates whether or not the literal translation hypothesis, which has been addressed in several areas of translation studies, can also be applied in ESP teaching/learning environments. If plausible, the assumptions on which this hypothesis is based can shed light on how learners disambiguate terms they encounter. Within this framework, this paper presents evidence that the literal translation hypothesis is possible in ESP; it offers the results of a pilot study that sheds light on how this hypothesis may work, and also discusses its usability in the context of ESP learning. In particular, this paper presents strategies for teaching multi-word terms that are different from those currently based on corpus data. We believe that exercises such as “cloze”, “fill in” and similar “guessing” exercises must be abandoned in ESP teaching/learning environments. Instead, we propose exercises that reproduce L1 teaching and learning activities, i.e., exercises that are typically used when acquiring specialised knowledge and skills in any domain, e.g. taking part in meetings and giving presentations in a business context.

  8. A developmental hypothesis to explain the multicentricity of breast cancer

    OpenAIRE

    Sharpe, C R

    1998-01-01

    In this article the author proposes that the multicentricity of breast cancer might be explained by a developmental hypothesis. Genetic alterations ("hits") occurring in epithelial stem cells during the development of the breast may be transmitted to populations of daughter cells during growth. As a result, areas of the breast may be predisposed to malignant transformation with the occurrence of further genetic hits. Areas with the same predisposition should be anatomically connected, and ear...

  9. Job Discrimination, Market Forces and the Invisibility Hypothesis

    OpenAIRE

    Paul R. Milgrom

    1984-01-01

    The Invisibility Hypothesis holds that the job skills of disadvantaged workers are not easily discovered by potential new employers, but that promotion enhances visibility and alleviates this problem. Then, at a competitive labor market equilibrium, firms profit by hiding talented disadvantaged workers in low level jobs. Consequently, those workers are paid less on average and promoted less often than others with the same education and ability. As a result of the inefficient and discriminator...

  10. Milton Friedman and the Emergence of the Permanent Income Hypothesis

    OpenAIRE

    Hsiang-Ke Chao

    2001-01-01

    The purpose of this paper is to investigate the evolution of MiltonFriedman's permanent income hypothesis from the 1940s to 1960s, andhow it became the paradigm of modern consumption theory. Modellingunobservables, such as permanent income and permanent consumption, isa long-standing issue in economics and econometrics. While theconventional approach has been to set an empirical model to make"permanent income" measurable, the historical change in the meaningof that theoretical construct is al...

  11. A Generalization of Refined Similarity Hypothesis for Isotropic Turbulence*

    Science.gov (United States)

    Hosokawa, Iwao

    2000-03-01

    The refined similarity hypothesis for isotropic turbulenceestablished by Kolmogorov in 1962 is generalized so that thestatistics of similarity variable may have a slight scale-ratiodependence. A reasonable form of the dependence is given on the basisof a recent multifractal model of intermittent energy dissipation andon some theoretical and experimental knowledge. This modificationleads us to predict reasonable values of all the Kolmogorov prefactorsand the scalings of longitudinal as well as transverse velocitystructure functions in isotropic turbulence.

  12. Language, Emotions, and Cultures: Emotional Sapir-Whorf Hypothesis

    OpenAIRE

    Perlovsky, Leonid

    2011-01-01

    An emotional version of Sapir-Whorf hypothesis suggests that differences in language emotionalities influence differences among cultures no less than conceptual differences. Conceptual contents of languages and cultures to significant extent are determined by words and their semantic differences; these could be borrowed among languages and exchanged among cultures. Emotional differences, as suggested in the paper, are related to grammar and mostly cannot be borrowed. Conceptual and emotional ...

  13. Visual perception and imagery: a new molecular hypothesis.

    Science.gov (United States)

    Bókkon, I

    2009-05-01

    Here, we put forward a redox molecular hypothesis about the natural biophysical substrate of visual perception and visual imagery. This hypothesis is based on the redox and bioluminescent processes of neuronal cells in retinotopically organized cytochrome oxidase-rich visual areas. Our hypothesis is in line with the functional roles of reactive oxygen and nitrogen species in living cells that are not part of haphazard process, but rather a very strict mechanism used in signaling pathways. We point out that there is a direct relationship between neuronal activity and the biophoton emission process in the brain. Electrical and biochemical processes in the brain represent sensory information from the external world. During encoding or retrieval of information, electrical signals of neurons can be converted into synchronized biophoton signals by bioluminescent radical and non-radical processes. Therefore, information in the brain appears not only as an electrical (chemical) signal but also as a regulated biophoton (weak optical) signal inside neurons. During visual perception, the topological distribution of photon stimuli on the retina is represented by electrical neuronal activity in retinotopically organized visual areas. These retinotopic electrical signals in visual neurons can be converted into synchronized biophoton signals by radical and non-radical processes in retinotopically organized mitochondria-rich areas. As a result, regulated bioluminescent biophotons can create intrinsic pictures (depictive representation) in retinotopically organized cytochrome oxidase-rich visual areas during visual imagery and visual perception. The long-term visual memory is interpreted as epigenetic information regulated by free radicals and redox processes. This hypothesis does not claim to solve the secret of consciousness, but proposes that the evolution of higher levels of complexity made the intrinsic picture representation of the external visual world possible by regulated

  14. Aquagenic keratoderma. Two new case reports and a new hypothesis

    Directory of Open Access Journals (Sweden)

    Georgi Tchernev

    2014-01-01

    Full Text Available Aquagenic keratoderma has been described as a transient condition affecting predominantly young females and defined clinically by the appearance of palmar hyper-wrinkling accentuated after immersion in water. We present two new cases with aquagenic palmoplantar acrokeratoderma - a child and a young male. A significant clinical improvement was achieved after topical treatment with aluminum salts. Aquagenic palmar keratoderma may be a clue to cystic fibrosis in adolescents and young adults. We developed a new hypothesis on its pathogenesis.

  15. Performing Detailed Diagnostics Using a Hypothesis Driven Approach

    Directory of Open Access Journals (Sweden)

    Ioana OLARIU

    2012-11-01

    Full Text Available This paper is about understanding through deep market analysis what are the issues and opportunities in distribution. It highlights the detailed hypotheses driven ‘diagnostic’ framework to perform this analysis and shows the selling force role in successfully managing distribution excellence as a change intervention. For each issue we built the most common hypotheses which can conduct to a certain situation and we have highlighted different type of key questions which can describe each hypothesis.

  16. Nonparametric hypothesis testing for equality of means on the simplex

    OpenAIRE

    Tsagris, Michail; Preston, Simon; Wood, Andrew T. A.

    2016-01-01

    In the context of data that lie on the simplex, we investigate use of empirical and exponential empirical likelihood, and Hotelling and James statistics, to test the null hypothesis of equal population means based on two independent samples. We perform an extensive numerical study using data simulated from various distributions on the simplex. The results, taken together with practical considerations regarding implementation, support the use of bootstrap-calibrated James statis...

  17. A hypothesis on the selective advantage for sleep

    OpenAIRE

    Tannenbaum, Emmanuel

    2005-01-01

    In this note, we present a hypothesis for the emergence of the phenomenon of sleep in organisms with sufficiently developed central nervous systems. We argue that sleep emerges because individual neurons must periodically enter a resting state and perform various ``garbage collection'' activities. Because the proper functioning of the central nervous system is dependent on the interconnections amongst a large collection of individual neurons, it becomes optimal, from the standpoint of the org...

  18. SU(7) GUT and evasion of the survival hypothesis

    International Nuclear Information System (INIS)

    Umemura, I.; Yamamoto, K.

    1981-01-01

    Characteristic features of an SU(7) GUT are discussed, in which the fundamental representation 7 consists of SU(5)'5 and its two singlets with charge q = +-1/2. The so-called survival hypothesis for fermions is naturally evaded by a kind of electric charge conservation due to q = +-1/2, and a brief comment on the suppression of the νsub(e) mass is given also. (orig.)

  19. The validity of the severity-psychosis hypothesis in depression

    DEFF Research Database (Denmark)

    Østergaard, Søren Dinesen; Stentoft-Hansen, Nils Lauge; Søltoft-Jensen, Henrik

    2012-01-01

    Psychotic depression (PD) is classified as a subtype of severe depression in the current diagnostic manuals. Accordingly, it is a common conception among psychiatrists that psychotic features in depression arise as a consequence of depressive severity. The aim of this study was to determine whether...... the severity of depressive and psychotic symptoms correlate in accordance with this "severity-psychosis" hypothesis and to detect potential differences in the clinical features of PD and non-psychotic depression (non-PD)....

  20. Chronic oxidative stress after irradiation: an unproven hypothesis

    OpenAIRE

    Cohen, Samuel R; Cohen, Eric P

    2012-01-01

    Injury and organ failure after irradiation of late-responding tissues is a substantial problem in radiation oncology and a major threat after accidental or belligerent exposures. The mechanisms of injury may include death of clonogens, vascular injury, activation of cytokine networks, and/or chronic oxidative stress. Knowledge of mechanisms may guide optimal use of mitigators. The hypothesis of chronic oxidative stress as a mechanism of late radiation injury has received much attention. We re...

  1. Hypothesis of Piezoelectricity of Inner Core As the Origin of Geomagnetism

    Directory of Open Access Journals (Sweden)

    Y Hayakawa

    2009-06-01

    Full Text Available A novel hypothesis is proposed that assumes piezoelectricity of the inner core as the origin of geomagnetism. By high pressure, electric charge is created on the surface and at the center of the earth. Inner core rotation yields a magnetic field. From the intensity and direction of geomagnetism at the present time, the surface charge density of the inner core is assumed to be -2x10-5C/m2. The rotation axis of the inner core is inclined by 10.4 degrees from that of the mantle. The inner core rotates with the mantle rotation. The reason for this is thought to be the eddy currents induced in the outer core of electrically conductive fluid that rotates with the mantle.

  2. Geometric and Topological Invariants of the Hypothesis Space

    Science.gov (United States)

    Rodríguez, Carlos C.

    2011-03-01

    The form and shape of a hypothesis space imposes natural objective constraints to any inferential process. This contribution summarizes what is currently known and the mathematics that are thought to be needed for new developments in this area. For example, it is well known that the quality of best possible estimators deteriorates with increasing volume, dimension and curvature of the hypothesis space. It is also known that regular statistical parametric models are finite dimensional Riemannian manifolds admitting a family of dual affine connections. Fisher information is the metric induced on the hypothesis space by the Hellinger distance. Nonparametric models are infinite dimensional manifolds. Global negative curvature implies asymptotic inadmissibility of uniform priors. When there is uncertainty about the model and the prior, entropic methods are more robust than standard Bayesian inference. The presence of some types of singularities allow the existence of faster than normal estimators …, etc. The large number of fundamental statistical concepts with geometric and topological content suggest to try to look at Riemannian Geometry, Algebraic Geometry, K-theory, Algebraic Topology, Knot-theory and other branches of current mathematics, not as empty esoteric abstractions but as allies for statistical inference.

  3. The differentiation hypothesis: distinguishing between perceiving and memorizing.

    Science.gov (United States)

    Galbraith, R C; Olsen, S F; Duerden, D S; Harris, W L

    1982-01-01

    The differentiation hypothesis states that perceiving and memorizing are functionally undifferentiated for young children (preschoolers). With age, additional strategies are implemented under intentional recall conditions, thus providing greater recall than under incidental conditions. Appel and colleagues presented initial evidence in 1972 that appeared to support the predicted Age X Recall Instruction (incidental, intentional) interaction of the differentiation hypothesis. Subsequent research in children's memory, however, has failed to replicate the critical features of the Appel et al. data. A closer look at Appel et al.'s procedures revealed a methodological flaw present in both their Experiments 1 and 2--the variable of instructional condition was manipulated within subjects. In addition, an inspection of their reported Age X Instruction interaction revealed a larger quadratic than linear component. The difference between incidental and intentional recall first increased and then decreased with age. Correcting for these errors of method and analysis, the present experiment found no support for the differentiation hypothesis. Recall did increase with age, but the increase was not differential with respect to incidental or intentional recall instructions.

  4. [Defensive pessimists and coping: the goodness of fit hypothesis].

    Science.gov (United States)

    Hosogoshi, Hiroki; Kodama, Masahiro

    2006-12-01

    The goodness of fit hypothesis (Lazarus & Folkman, 1984) posits that it is adaptive to use emotion-focused coping and not to use problem-focused coping in uncontrollable situations. This study examines the coping skills that defensive pessimists (DPs) tend to use in uncontrollable situations. The participants were 282 Japanese college students, from which 61 DPs and 64 strategic optimists (SOs) were identified. Based on the controllability they reported about recalled stress situations, they were classified into controllable or uncontrollable subgroups. Eight coping skills, which are concerned with emotion-focused or problem-focused coping, were compared. T-test and analysis of variance (ANOVA) showed that DPs in uncontrollable situations tended not to use emotion-focused coping, which is not consistent with the goodness of fit hypothesis, but they also tended not to use problem-focused coping, which is consistent with the hypothesis. These results imply that DPs can control their behavior adaptively so they do not increase stress more in uncontrollable situations, although they have a vulnerability to feel stress easily because they can not use emotion-focused coping effectively.

  5. Testing competing forms of the Milankovitch hypothesis: A multivariate approach

    Science.gov (United States)

    Kaufmann, Robert K.; Juselius, Katarina

    2016-02-01

    We test competing forms of the Milankovitch hypothesis by estimating the coefficients and diagnostic statistics for a cointegrated vector autoregressive model that includes 10 climate variables and four exogenous variables for solar insolation. The estimates are consistent with the physical mechanisms postulated to drive glacial cycles. They show that the climate variables are driven partly by solar insolation, determining the timing and magnitude of glaciations and terminations, and partly by internal feedback dynamics, pushing the climate variables away from equilibrium. We argue that the latter is consistent with a weak form of the Milankovitch hypothesis and that it should be restated as follows: internal climate dynamics impose perturbations on glacial cycles that are driven by solar insolation. Our results show that these perturbations are likely caused by slow adjustment between land ice volume and solar insolation. The estimated adjustment dynamics show that solar insolation affects an array of climate variables other than ice volume, each at a unique rate. This implies that previous efforts to test the strong form of the Milankovitch hypothesis by examining the relationship between solar insolation and a single climate variable are likely to suffer from omitted variable bias.

  6. Alertness and Cognitive Control: Testing the Early Onset Hypothesis.

    Science.gov (United States)

    Schneider, Darryl W

    2017-11-20

    Previous research has revealed a peculiar interaction between alertness and cognitive control in selective-attention tasks: Congruency effects are larger on alert trials (on which an alerting cue is presented briefly in advance of the imperative stimulus) than on no-alert trials, despite shorter response times (RTs) on alert trials. One explanation for this finding is the early onset hypothesis, which is based on the assumptions that increased alertness shortens stimulus-encoding time and that cognitive control involves gradually focusing attention during a trial. The author tested the hypothesis in 3 experiments by manipulating alertness and stimulus quality (which were intended to shorten and lengthen stimulus-encoding time, respectively) in an arrow-based flanker task involving congruent and incongruent stimuli. Replicating past findings, the alerting manipulation led to shorter RTs but larger congruency effects on alert trials than on no-alert trials. The stimulus-quality manipulation led to longer RTs and larger congruency effects for degraded stimuli than for intact stimuli. These results provide mixed support for the early onset hypothesis, but the author discusses how data and theory might be reconciled if stimulus quality affects stimulus-encoding time and the rate of evidence accumulation in the decision process. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  7. The concept possession hypothesis of self-consciousness.

    Science.gov (United States)

    Savanah, Stephane

    2012-06-01

    This paper presents the hypothesis that concept possession is sufficient and necessary for self-consciousness. If this is true it provides a yardstick for gauging the validity of different research paradigms in which claims for self-consciousness in animals or human infants are made: a convincing demonstration of concept possession in a research subject, such as a display of inferential reasoning, may be taken as conclusive evidence of self-consciousness. Intuitively, there appears to be a correlation between intelligence in animals (which presupposes concept possession) and the existence of self-consciousness. I present three discussions to support the hypothesis: an analogy between perception and conception, where both are self-specifying; an argument that any web of concepts will always include the self-concept; and a fresh interpretation of Bermũdez (1998) showing how his theory of non-conceptual content provides strong support for the concept possession hypothesis. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. A test of the substitution-habitat hypothesis in amphibians.

    Science.gov (United States)

    Martínez-Abraín, Alejandro; Galán, Pedro

    2017-12-08

    Most examples that support the substitution-habitat hypothesis (human-made habitats act as substitutes of original habitat) deal with birds and mammals. We tested this hypothesis in 14 amphibians by using percentage occupancy as a proxy of habitat quality (i.e., higher occupancy percentages indicate higher quality). We classified water body types as original habitat (no or little human influence) depending on anatomical, behavioral, or physiological adaptations of each amphibian species. Ten species had relatively high probabilities (0.16-0.28) of occurrence in original habitat, moderate probability of occurrence in substitution habitats (0.11-0.14), and low probability of occurrence in refuge habitats (0.05-0.08). Thus, the substitution-habitat hypothesis only partially applies to amphibians because the low occupancy of refuges could be due to the negligible human persecution of this group (indicating good conservation status). However, low occupancy of refuges could also be due to low tolerance of refuge conditions, which could have led to selective extinction or colonization problems due to poor dispersal capabilities. That original habitats had the highest probabilities of occupancy suggests amphibians have a good conservation status in the region. They also appeared highly adaptable to anthropogenic substitution habitats. © 2017 Society for Conservation Biology.

  9. Biological fingerprint of high LET radiation. Brenner hypothesis

    International Nuclear Information System (INIS)

    Kodama, Yoshiaki; Awa, Akio; Nakamura, Nori

    1997-01-01

    Hypothesis by Brenner et al. (1994) that in chromosome aberrations in human peripheral lymphocytes induced by radiation exposure, F value (dicentrics/rings) differs dependently on the LET and can be a biomarker of high LET radiation like neutron and α-ray was reviewed and evaluated as follows. Radiation and chromosome aberrations; in this section, unstable aberrations like dicentric and rings (r) and stable ones like translocation and pericentric inversions were described. F value. Brenner hypothesis. Bauchinger's refutation. F value determined by FISH method; here, FISH is fluorescence in situ hybridization. F value in studies by author's Radiation Effect Research Facility. Frequency of chromosome aberration in A-bomb survivors and ESR (ESR: electron spin resonance). The cause for fluctuation of F values. The Brenner hypothesis could not be supported by studies by author's facility, suggesting that the rate of inter-chromosomal and intra-chromosomal exchange abnormalities can not be distinguishable by the radiation LET. This might be derived from the difference in detection technology of r rather than in LET. (K.H.)

  10. Generalized probabilistic theories without the no-restriction hypothesis

    Science.gov (United States)

    Janotta, Peter; Lal, Raymond

    2013-05-01

    The framework of generalized probabilistic theories is a popular approach for studying the physical foundations of quantum theory. The standard framework assumes the no-restriction hypothesis, in which the state space of a physical theory determines the set of measurements. However, this assumption is not physically motivated. We generalize the framework to account for systems that do not obey the no-restriction hypothesis. We then show how our framework can be used to describe certain classes of probabilistic theories, for example, those which include intrinsic noise. Relaxing the restriction hypothesis also allows us to introduce a “self-dualization” procedure, which yields a class of theories that share many features of quantum theory. We then characterize joint states, generalizing the maximal tensor product. We show how this tensor product can be used to describe the convex closure of the Spekkens toy theory, and in doing so we obtain an analysis of why it is local in terms of the geometry of its state space. We show that the unrestricted version of the Spekkens toy theory is the theory known as “boxworld” that allows maximal nonlocal correlations.

  11. Nonstrategic Nuclear Weapons at an Inflection Point

    Science.gov (United States)

    2017-07-01

    an exercise ................................................22 figure 9. Nato enlargement ...defenselink.mil) [Public domain], via Wikimedia Commons, https://commons.wikimedia.org/wiki/File%3ANATO_Summit_in_ Washington_1999.jpg; right, NATO Enlargement ... NATO enlargement and oft-expressed displeasure with the post–Cold War international order led by the United States. We then examine events of an

  12. Why Does REM Sleep Occur? A Wake-up Hypothesis

    Directory of Open Access Journals (Sweden)

    Dr. W. R. eKlemm

    2011-09-01

    Full Text Available Brain activity differs in the various sleep stages and in conscious wakefulness. Awakening from sleep requires restoration of the complex nerve impulse patterns in neuronal network assemblies necessary to re-create and sustain conscious wakefulness. Herein I propose that the brain uses REM to help wake itself up after it has had a sufficient amount of sleep. Evidence suggesting this hypothesis includes the facts that, 1 when first going to sleep, the brain plunges into Stage N3 (formerly called Stage IV, a deep abyss of sleep, and, as the night progresses, the sleep is punctuated by episodes of REM that become longer and more frequent toward morning, 2 conscious-like dreams are a reliable component of the REM state in which the dreamer is an active mental observer or agent in the dream, 3 the last awakening during a night’s sleep usually occurs in a REM episode during or at the end of a dream, 4 both REM and awake consciousness seem to arise out of a similar brainstem ascending arousal system 5 N3 is a functionally perturbed state that eventually must be corrected so that embodied brain can direct adaptive behavior, and 6 corticofugal projections to brainstem arousal areas provide a way to trigger increased cortical activity in REM to progressively raise the sleeping brain to the threshold required for wakefulness. This paper shows how the hypothesis conforms to common experience and has substantial predictive and explanatory power regarding the phenomenology of sleep in terms of ontogeny, aging, phylogeny, abnormal/disease states, cognition, and behavioral physiology. That broad range of consistency is not matched by competing theories, which are summarized herein. Specific ways to test this wake-up hypothesis are suggested. Such research could lead to a better understanding of awake consciousness.

  13. Why does rem sleep occur? A wake-up hypothesis.

    Science.gov (United States)

    Klemm, W R

    2011-01-01

    Brain activity differs in the various sleep stages and in conscious wakefulness. Awakening from sleep requires restoration of the complex nerve impulse patterns in neuronal network assemblies necessary to re-create and sustain conscious wakefulness. Herein I propose that the brain uses rapid eye movement (REM) to help wake itself up after it has had a sufficient amount of sleep. Evidence suggesting this hypothesis includes the facts that, (1) when first going to sleep, the brain plunges into Stage N3 (formerly called Stage IV), a deep abyss of sleep, and, as the night progresses, the sleep is punctuated by episodes of REM that become longer and more frequent toward morning, (2) conscious-like dreams are a reliable component of the REM state in which the dreamer is an active mental observer or agent in the dream, (3) the last awakening during a night's sleep usually occurs in a REM episode during or at the end of a dream, (4) both REM and awake consciousness seem to arise out of a similar brainstem ascending arousal system (5) N3 is a functionally perturbed state that eventually must be corrected so that embodied brain can direct adaptive behavior, and (6) cortico-fugal projections to brainstem arousal areas provide a way to trigger increased cortical activity in REM to progressively raise the sleeping brain to the threshold required for wakefulness. This paper shows how the hypothesis conforms to common experience and has substantial predictive and explanatory power regarding the phenomenology of sleep in terms of ontogeny, aging, phylogeny, abnormal/disease states, cognition, and behavioral physiology. That broad range of consistency is not matched by competing theories, which are summarized herein. Specific ways to test this wake-up hypothesis are suggested. Such research could lead to a better understanding of awake consciousness.

  14. [Examination of the hypothesis 'the factors and mechanisms of superiority'].

    Science.gov (United States)

    Sierra-Fitzgerald, O; Quevedo-Caicedo, J; López-Calderón, M G

    INTRODUCTION. The hypothesis of Geschwind and Galaburda suggests that specific cognitive superiority arises as a result of an alteration in development of the nervous system. In this article we review the co existence of superiority and inferiority . PATIENTS AND METHODS. A study was made of six children aged between 6 and 8 years old at the Instituto de Belles Artes Antonio Maria Valencia in Cali,Columbia with an educational level between second and third grade at a primary school and of medium low socio economic status. The children were considered to have superior musical ability by music experts, which is the way in which the concept of superiority was to be tested. The concept of inferiority was tested by neuropsychological tests = 1.5 DE below normal for the same age. We estimated the perinatal neurological risk in each case. Subsequently the children s general intelligence and specific cognitive abilities were evaluated. In the first case the WISC R and MSCA were used. The neuropsychological profiles were obtained by broad evaluation using a verbal fluency test, a test using counters, Boston vocabulary test, the Wechster memory scale, sequential verbal memory test, super imposed figures test, Piaget Head battery, Rey Osterrieth complex figure and the Wisconsin card classification test. The RESULTS showed slight/moderate deficits in practical construction ability and mild defects of memory and concept abilities. In general the results supported the hypothesis tested. The mechanisms of superiority proposed in the classical hypothesis mainly involve the contralateral hemisphere: in this study the ipsilateral mechanism was more important.

  15. How organisms do the right thing: The attractor hypothesis

    Science.gov (United States)

    Emlen, J.M.; Freeman, D.C.; Mills, A.; Graham, J.H.

    1998-01-01

    Neo-Darwinian theory is highly successful at explaining the emergence of adaptive traits over successive generations. However, there are reasons to doubt its efficacy in explaining the observed, impressively detailed adaptive responses of organisms to day-to-day changes in their surroundings. Also, the theory lacks a clear mechanism to account for both plasticity and canalization. In effect, there is a growing sentiment that the neo-Darwinian paradigm is incomplete, that something more than genetic structure, mutation, genetic drift, and the action of natural selection is required to explain organismal behavior. In this paper we extend the view of organisms as complex self-organizing entities by arguing that basic physical laws, coupled with the acquisitive nature of organisms, makes adaptation all but tautological. That is, much adaptation is an unavoidable emergent property of organisms' complexity and, to some a significant degree, occurs quite independently of genomic changes wrought by natural selection. For reasons that will become obvious, we refer to this assertion as the attractor hypothesis. The arguments also clarify the concept of "adaptation." Adaptation across generations, by natural selection, equates to the (game theoretic) maximization of fitness (the success with which one individual produces more individuals), while self-organizing based adaptation, within generations, equates to energetic efficiency and the matching of intake and biosynthesis to need. Finally, we discuss implications of the attractor hypothesis for a wide variety of genetical and physiological phenomena, including genetic architecture, directed mutation, genetic imprinting, paramutation, hormesis, plasticity, optimality theory, genotype-phenotype linkage and puncuated equilibrium, and present suggestions for tests of the hypothesis. ?? 1998 American Institute of Physics.

  16. [Dr James Lovelock and story about GAIA hypothesis].

    Science.gov (United States)

    Gajić, Vladimir

    2011-01-01

    Gaia is the Anglo-Saxon term for the Hellenic term Gea or Ge, which means Earth. The GAIA hypothesis was launched almost 40 years ago by the famous chemist James Lovelock, who was engaged by the National Aeronautics and Space Administration (NASA) to create a sensitive instrument for searching forms of extraterrestrial life on other planets. Then he published the book The ages of GAIA, which perturbed the world's scientific public of those days. Lovelock struck upon this idea in the late sixties of the past century, during the space race with Russians, when he was hired hy the National Aeronautics and Space Administration to conduct a series of experiments to find and explore life forms on the planet Mars. Experiments executed by the American module Viking failed to trace any life form, as Lovelock had predicted. He called it a dead equilibrium. Then he turned to Earth, whose perspective is totally different from its first neighbors. Venus and Mars, and is far from a dead equilibrium. DAISYWORLD: In this hypothesis. Lovelock represents Earth as one living, giant super organism, composed of all living creatures and its material environnent. In that super organisnm, the level of oxygen, weather conditions, ocean salinity and so on are under constant influence of physical, chemical and biological processes, which provide the existence for such life forms on Earth. Dr James Lovelock represents a pioneer of climatology, and his hypothesis gives a unique insight into the correlation of dynamic processes on our planet, no matter whether they are of physical or biological nature.

  17. Creativity and Autism Spectrum Conditions: a Hypothesis on Lewis Carroll

    Directory of Open Access Journals (Sweden)

    Stefano Calabrese

    2017-06-01

    Full Text Available The hypothesis formulated by Simon Baron-Cohen and his collaborators on the onset of autistic syndromes and their link with an excess of the so-called S brain is reflected in the work of Lewis Carroll, a formal logic and mathematics professor deeply inclined to visual and spatial descriptions, interested in affordances and systemic circuits, and devoid of empathic tendencies in creating his characters. In the future, this finding may serve as a test for predicting autism spectrum disorders and support the elaboration of narrative artefact for therapeutic purposes in relation to people with autism.

  18. Yawning, fatigue, and cortisol: expanding the Thompson Cortisol Hypothesis.

    Science.gov (United States)

    Thompson, Simon B N

    2014-10-01

    Yawning and its involvement in neurological disorders has become the new scientific conundrum. Cortisol levels are known to rise during stress and fatigue; yawning may occur when we are under stress or tired. However, the link between yawning, fatigue, and cortisol has not been fully understood. Expansion of the Thompson Cortisol Hypothesis proposes that the stress hormone, cortisol, is responsible for yawning and fatigue especially in people with incomplete innervation such as multiple sclerosis. This informs our understanding of the functional importance of the brain stem region of the brain in regulating stress and fatigue. Copyright © 2014 The Author. Published by Elsevier Ltd.. All rights reserved.

  19. The athlete's heart: a contemporary appraisal of the 'Morganroth hypothesis'.

    Science.gov (United States)

    Naylor, Louise H; George, Keith; O'Driscoll, Gerry; Green, Daniel J

    2008-01-01

    As early as 1975, Morganroth and colleagues hypothesized that the cardiac morphological adaptation observed in athletes corresponded with the nature of the haemodynamic stimulus imposed on the ventricles during repeated exercise bouts. Endurance training purportedly leads to an eccentric form of cardiac hypertrophy, principally characterized by increased left ventricular (LV) cavity dimension, and thus LV mass (LVM), as a consequence of prolonged repetitive volume overload. In contrast, strength training is supposedly associated with a concentric form of hypertrophy where increased ventricular wall thickness, with no change in cavity size, underpins the elevated LVM as a consequence of the pressure overload produced during strenuous resistive exercise. The 'Morganroth hypothesis' has been broadly adopted in the scientific and medical literature, partly as a consequence of a large body of cross-sectional evidence suggesting that endurance athletes have greater cavity dimensions than control subjects or resistance athletes. However, in conflict with the 'Morganroth hypothesis', several studies suggest that LV wall thickness is increased more in endurance-, than strength-trained athletes and others have reported no morphological changes in resistance-trained athletes. Such controversial data may reflect variability in the training stimuli, with little obvious attempt to quantify these issues in previous research. Further reflection on the 'Morganroth hypothesis' may also be pertinent as more sensitive technologies, such as magnetic resonance imaging, are now being employed for the assessment of cardiac morphology. Finally, the process of scaling (or normalizing) cardiac size for between-subject differences in body size and composition has further complicated the description and understanding of cardiac morphology in athletes. Specifically, it is possible that the increased LVM observed in some athletes may merely reflect a 'larger than normal' body size. These

  20. Quadratic Forms and Semiclassical Eigenfunction Hypothesis for Flat Tori

    Science.gov (United States)

    T. Sardari, Naser

    2018-03-01

    Let Q( X) be any integral primitive positive definite quadratic form in k variables, where {k≥4}, and discriminant D. For any integer n, we give an upper bound on the number of integral solutions of Q( X) = n in terms of n, k, and D. As a corollary, we prove a conjecture of Lester and Rudnick on the small scale equidistribution of almost all functions belonging to any orthonormal basis of a given eigenspace of the Laplacian on the flat torus {T^d} for {d≥ 5}. This conjecture is motivated by the work of Berry [2,3] on the semiclassical eigenfunction hypothesis.

  1. Water Pollution Detection Based on Hypothesis Testing in Sensor Networks

    Directory of Open Access Journals (Sweden)

    Xu Luo

    2017-01-01

    Full Text Available Water pollution detection is of great importance in water conservation. In this paper, the water pollution detection problems of the network and of the node in sensor networks are discussed. The detection problems in both cases of the distribution of the monitoring noise being normal and nonnormal are considered. The pollution detection problems are analyzed based on hypothesis testing theory firstly; then, the specific detection algorithms are given. Finally, two implementation examples are given to illustrate how the proposed detection methods are used in the water pollution detection in sensor networks and prove the effectiveness of the proposed detection methods.

  2. From animal cruelty to serial murder: applying the graduation hypothesis.

    Science.gov (United States)

    Wright, Jeremy; Hensley, Christopher

    2003-02-01

    Although serial murder has been recorded for centuries, limited academic attention has been given to this important topic. Scholars have attempted to examine the causality and motivations behind the rare phenomenon of serial murder. However, scant research exists which delves into the childhood characteristics of serial murderers. Using social learning theory, some of these studies present supporting evidence for a link between childhood animal cruelty and adult aggression toward humans. Based on five case studies of serial murderers, we contribute to the existing literature by exploring the possible link between childhood cruelty toward animals and serial murder with the application of the graduation hypothesis.

  3. Conjecture and hypothesis: The importance of reality checks

    Directory of Open Access Journals (Sweden)

    David Deamer

    2017-03-01

    Full Text Available In origins of life research, it is important to understand the difference between conjecture and hypothesis. This commentary explores the difference and recommends alternative hypotheses as a way to advance our understanding of how life can begin on the Earth and other habitable planets. As an example of how this approach can be used, two conditions have been proposed for sites conducive to the origin of life: hydrothermal vents in salty seawater, and fresh water hydrothermal fields associated with volcanic landmasses. These are considered as alternative hypotheses and the accumulating weight of evidence for each site is described and analyzed.

  4. Nearly Efficient Likelihood Ratio Tests of the Unit Root Hypothesis

    DEFF Research Database (Denmark)

    Jansson, Michael; Nielsen, Morten Ørregaard

    Seemingly absent from the arsenal of currently available "nearly efficient" testing procedures for the unit root hypothesis, i.e. tests whose local asymptotic power functions are indistinguishable from the Gaussian power envelope, is a test admitting a (quasi-)likelihood ratio interpretation. We...... show that the likelihood ratio unit root test derived in a Gaussian AR(1) model with standard normal innovations is nearly efficient in that model. Moreover, these desirable properties carry over to more complicated models allowing for serially correlated and/or non-Gaussian innovations....

  5. Cosmic-ray antimatter - A primary origin hypothesis

    Science.gov (United States)

    Stecker, F. W.; Protheroe, R. J.; Kazanas, D.

    1983-01-01

    The present investigation is concerned with the possibility that the observed cosmic-ray protons are of primary extragalactic origin, taking into account the significance of the current antiproton data. Attention is given to questions regarding primary antiprotons, antihelium fluxes, and the propagation of extragalactic cosmic rays. It is concluded that the primary origin hypothesis should be considered as a serious alternative explanation for the cosmic-ray antiproton fluxes. Such extragalactic primary origin can be considered in the context of a baryon symmetric domain cosmology. The fluxes and propagation characteristics suggested are found to be in rough agreement with the present antiproton data.

  6. Segmentation by Large Scale Hypothesis Testing - Segmentation as Outlier Detection

    DEFF Research Database (Denmark)

    Darkner, Sune; Dahl, Anders Lindbjerg; Larsen, Rasmus

    2010-01-01

    We propose a novel and efficient way of performing local image segmentation. For many applications a threshold of pixel intensities is sufficient but determine the appropriate threshold value can be difficult. In cases with large global intensity variation the threshold value has to be adapted...... locally. We propose a method based on large scale hypothesis testing with a consistent method for selecting an appropriate threshold for the given data. By estimating the background distribution we characterize the segment of interest as a set of outliers with a certain probability based on the estimated...

  7. Riemann hypothesis for period polynomials of modular forms.

    Science.gov (United States)

    Jin, Seokho; Ma, Wenjun; Ono, Ken; Soundararajan, Kannan

    2016-03-08

    The period polynomial r(f)(z) for an even weight k≥4 newform f∈S(k)(Γ(0)((N)) is the generating function for the critical values of L(f,s) . It has a functional equation relating r(f)(z) to r(f)(-1/Nz). We prove the Riemann hypothesis for these polynomials: that the zeros of r(f)(z) lie on the circle |z|=1/√N . We prove that these zeros are equidistributed when either k or N is large.

  8. Ten Challenges of the Amyloid Hypothesis of Alzheimer's Disease

    DEFF Research Database (Denmark)

    Kepp, Kasper Planeta

    2017-01-01

    of the major paradigm in the field, the amyloid hypothesis, are sharply formulated. These challenges together show that new approaches are necessary that address data heterogeneity, increase focus on the proteome level, use available human patient data more actively, account for the aging phenotype......The inability to effectively halt or cure Alzheimer's disease (AD), exacerbated by the recent failures of high-profile clinical trials, emphasizes the urgent need to understand the complex biochemistry of this major neurodegenerative disease. In this paper, ten central, current challenges...

  9. The food-insecurity obesity paradox: A resource scarcity hypothesis.

    Science.gov (United States)

    Dhurandhar, Emily J

    2016-08-01

    Food insecurity is paradoxically associated with obesity in the United States. Current hypotheses to explain this phenomenon are descriptive regarding the low food security population's dietary and physical activity habits, but are not mechanistic. Herein it is proposed that a resource scarcity hypothesis may explain this paradox, such that fattening is a physiologically regulated response to threatened food supply that occurs specifically in low social status individuals. Evidence that this may be occurring, the implications for addressing the food insecurity-obesity paradox, and future areas of research, are reviewed and discussed. Copyright © 2016. Published by Elsevier Inc.

  10. A Critique of One-Tailed Hypothesis Test Procedures in Business and Economics Statistics Textbooks.

    Science.gov (United States)

    Liu, Tung; Stone, Courtenay C.

    1999-01-01

    Surveys introductory business and economics statistics textbooks and finds that they differ over the best way to explain one-tailed hypothesis tests: the simple null-hypothesis approach or the composite null-hypothesis approach. Argues that the composite null-hypothesis approach contains methodological shortcomings that make it more difficult for…

  11. Explanation of changes of stellar radiation polarization by means of an ''active longitudes'' hypothesis with U Mon as an example

    International Nuclear Information System (INIS)

    Polyakova, T.A.

    1980-01-01

    The hypothesis explaining the variability of some stars with U Mon as an example resulting from antipodal active regions on their surface is discussed qualitatively. The plane of polarization is determined by average magnetic field of the bipolar active region. The changes of polarization and brightness are assumed to be connected with the star rotation. The rotation period is taken to be twice as much as the period doubling of spectral lines

  12. Pornography actresses: an assessment of the damaged goods hypothesis.

    Science.gov (United States)

    Griffith, James D; Mitchell, Sharon; Hart, Christian L; Adams, Lea T; Gu, Lucy L

    2013-01-01

    The damaged goods hypothesis posits that female performers in the adult entertainment industry have higher rates of childhood sexual abuse (CSA), psychological problems, and drug use compared to the typical woman. The present study compared the self-reports of 177 porn actresses to a sample of women matched on age, ethnicity, and marital status. Comparisons were conducted on sexual behaviors and attitudes, self-esteem, quality of life, and drug use. Porn actresses were more likely to identify as bisexual, first had sex at an earlier age, had more sexual partners, were more concerned about contracting a sexually transmitted disease (STD), and enjoyed sex more than the matched sample, although there were no differences in incidence of CSA. In terms of psychological characteristics, porn actresses had higher levels of self-esteem, positive feelings, social support, sexual satisfaction, and spirituality compared to the matched group. Last, female performers were more likely to have ever used 10 different types of drugs compared to the comparison group. A discriminant function analysis was able to correctly classify 83% of the participants concerning whether they were a porn actress or member of the matched sample. These findings did not provide support for the damaged goods hypothesis.

  13. On the Pathogenesis of Alzheimer's Disease: The MAM Hypothesis.

    Science.gov (United States)

    Area-Gomez, Estela; Schon, Eric A

    2017-03-01

    The pathogenesis of Alzheimer's disease (AD) is currently unclear and is the subject of much debate. The most widely accepted hypothesis designed to explain AD pathogenesis is the amyloid cascade, which invokes the accumulation of extracellular plaques and intracellular tangles as playing a fundamental role in the course and progression of the disease. However, besides plaques and tangles, other biochemical and morphological features are also present in AD, often manifesting early in the course of the disease before the accumulation of plaques and tangles. These include altered calcium, cholesterol, and phospholipid metabolism; altered mitochondrial dynamics; and reduced bioenergetic function. Notably, these other features of AD are associated with functions localized to a subdomain of the endoplasmic reticulum (ER), known as mitochondria-associated ER membranes (MAMs). The MAM region of the ER is a lipid raft-like domain closely apposed to mitochondria in such a way that the 2 organelles are able to communicate with each other, both physically and biochemically, thereby facilitating the functions of this region. We have found that MAM-localized functions are increased significantly in cellular and animal models of AD and in cells from patients with AD in a manner consistent with the biochemical findings noted above. Based on these and other observations, we propose that increased ER-mitochondrial apposition and perturbed MAM function lie at the heart of AD pathogenesis.-Area-Gomez, E., Schon, E. A. On the pathogenesis of Alzheimer's disease: the MAM hypothesis. © FASEB.

  14. Romanticism and schizophrenia. Second part: The intimacy hypothesis.

    Science.gov (United States)

    López-Ibor, Juan J; López-Ibor, María I

    2014-01-01

    In the first part of this article we have analyzed the evidence supporting the recency hypothesis of schizophrenia and also what we can call the intimate nature of the disease. In this part we highlight the role of certain cultural aspects that have been ignored up to now, aspects that are associated with deep changes in the Weltanschauung and systems of beliefs on human nature brought up by the late Modernism, specifically by Romanticism. The description of the main characteristics of Romanticism, starting with the “discovery of intimacy”, leads to the conclusion that the characteristic alteration of subjectivity and ipseity of the disease appears to be a vulnerability factor when somebody has to face the new challenges raise Romanticism. The consideration of Hölderlin’s literary achievements and the deep psychological drama prevailing in them, makes explicit how the late modern human being finds in Romanticism the source of creativity and personal development but also the threat of his or her own destruction. Finally we link our hypothesis with recent genetic perspectives that consider sets of diseases associated to the same gene or genes (diseasome). In any case the process of associating the traits of Late Modernism and Romanticism with the core features of schizophrenia allows to consider the amalgamation of insanity with society, both at a general level an in what concerns individual patients, paving the way for novel therapeutic strategies.

  15. The influence of symbolic literacy on memory: testing Plato's hypothesis.

    Science.gov (United States)

    Eskritt, M; Lee, K; Donald, M

    2001-03-01

    The present study examined the influence of the production of external symbols on memory strategies. Plato hypothesized that dependency on writing as an external memory store would be deterimental to memory. Three experiments were conducted to explore this hypothesis. Participants played Concentration, a memory game where players must find matching pairs of cards placed face down in an array. Participants were allowed to make notes to aid their performance under some experimental conditions, while under other conditions they could not. In Experiments 1 and 2, the unexpected removal of participants' notes revealed that the performance benefit was due to notes acting as a form of external memory storage, rather than as an aid to encoding information in memory. Experiment 3 qualified these findings by demonstrating that the identity of each card was retained in memory, while the location of each card tended to be stored in the participants' external notations. These data suggest a modified interpretation of Plato's hypothesis in that symbolic literacy may change how we remember information. Rather than storing all information in memory, we only have to retain the information necessary to use the much larger storage capacity of the external system. Thus, the introduction of external symbols allows for a change in how memory is adaptively distributed.

  16. Pathogenesis of and unifying hypothesis for idiopathic pouchitis.

    LENUS (Irish Health Repository)

    Coffey, J Calvin

    2009-04-01

    Ileal pouch-anal anastomosis is the procedure of choice in the surgical management of refractory ulcerative colitis. Pouchitis affects up to 60% of patients following ileal pouch-anal anastomosis for ulcerative colitis. It overlaps significantly with ulcerative colitis such that improvements in our understanding of one will impact considerably on the other. The symptoms are distressing and impinge significantly on patients\\' quality of life. Despite 30 years of scientific and clinical investigation, the pathogenesis of pouchitis is unknown; however, recent advances in molecular and cell biology make a synergistic hypothesis possible. This hypothesis links interaction between epithelial metaplasia, changes in luminal bacteria (in particular sulfate-reducing bacteria), and altered mucosal immunity. Specifically, colonic metaplasia supports colonization by sulfate-reducing bacteria that produce hydrogen sulfide. This causes mucosal depletion and subsequent inflammation. Although in most cases antibiotics lead to bacterial clearance and symptom resolution, immunogenetic subpopulations can develop a chronic refractory variant of pouchitis. The aims of this paper are to discuss proposed pathogenic mechanisms and to describe a novel mechanism that combines many hypotheses and explains several aspects of pouchitis. The implications for the management of both pouchitis and ulcerative colitis are discussed.

  17. Pathogenesis of and unifying hypothesis for idiopathic pouchitis.

    LENUS (Irish Health Repository)

    Coffey, J Calvin

    2012-02-01

    Ileal pouch-anal anastomosis is the procedure of choice in the surgical management of refractory ulcerative colitis. Pouchitis affects up to 60% of patients following ileal pouch-anal anastomosis for ulcerative colitis. It overlaps significantly with ulcerative colitis such that improvements in our understanding of one will impact considerably on the other. The symptoms are distressing and impinge significantly on patients\\' quality of life. Despite 30 years of scientific and clinical investigation, the pathogenesis of pouchitis is unknown; however, recent advances in molecular and cell biology make a synergistic hypothesis possible. This hypothesis links interaction between epithelial metaplasia, changes in luminal bacteria (in particular sulfate-reducing bacteria), and altered mucosal immunity. Specifically, colonic metaplasia supports colonization by sulfate-reducing bacteria that produce hydrogen sulfide. This causes mucosal depletion and subsequent inflammation. Although in most cases antibiotics lead to bacterial clearance and symptom resolution, immunogenetic subpopulations can develop a chronic refractory variant of pouchitis. The aims of this paper are to discuss proposed pathogenic mechanisms and to describe a novel mechanism that combines many hypotheses and explains several aspects of pouchitis. The implications for the management of both pouchitis and ulcerative colitis are discussed.

  18. Modulation-demodulation hypothesis of periodic breathing in human respiration.

    Science.gov (United States)

    Pal, Tanmay; Dutta, Pranab Kumar; Maka, Srinivasu

    2018-03-08

    Periodic breathing (PB) is a diseased condition of the cardiorespiratory system, and mathematically it is modelled as an oscillation. Modeling approaches replicate periodic oscillation in the minute ventilation due to a higher than normal gain of the feedback signals from the chemoreceptors coupled with a longer than normal latency in feedback, and do not consider the waxing-waning pattern of the oronasal airflow. In this work, a noted regulation model is extended by integrating respiratory mechanics and respiratory central pattern generator (rCPG) model, using modulation-demodulation 1 hypothesis. This is a top-down modeling approach, and it is assumed that the sensory feedback signal from the chemoreceptors modulates the output of the rCPG model. It is also assumed that the brainstem network is responsible for the demodulation process. The respiratory mechanics is modeled as a multi-input multi-output (MIMO) system, where modulated and demodulated neural signals are applied as input and the minute ventilation and the oronasal airflow are specified as output. The minute ventilation signal drives the regulation model, completing the feedback loop. The proposed model is validated by comparing the model output with the clinical data. Using the modulation-demodulation hypothesis, a respiratory mechanics model is formulated in the form of a linear state-space model, which can be useful for providing assisted ventilation in clinical conditions. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Verifying the Simulation Hypothesis via Infinite Nested Universe Simulacrum Loops

    Science.gov (United States)

    Sharma, Vikrant

    2017-01-01

    The simulation hypothesis proposes that local reality exists as a simulacrum within a hypothetical computer's dimension. More specifically, Bostrom's trilemma proposes that the number of simulations an advanced 'posthuman' civilization could produce makes the proposition very likely. In this paper a hypothetical method to verify the simulation hypothesis is discussed using infinite regression applied to a new type of infinite loop. Assign dimension n to any computer in our present reality, where dimension signifies the hierarchical level in nested simulations our reality exists in. A computer simulating known reality would be dimension (n-1), and likewise a computer simulating an artificial reality, such as a video game, would be dimension (n +1). In this method, among others, four key assumptions are made about the nature of the original computer dimension n. Summations show that regressing such a reality infinitely will create convergence, implying that the verification of whether local reality is a grand simulation is feasible to detect with adequate compute capability. The action of reaching said convergence point halts the simulation of local reality. Sensitivities to the four assumptions and implications are discussed.

  20. A hypothesis to explain lichen-Rangifer dynamic relationships

    Directory of Open Access Journals (Sweden)

    Eldar Gaare

    1997-04-01

    Full Text Available A small group of fruticous lichen species, viz. Cetraria nivalis, Cladonia mitis, C. stellaris, and Stereocaulon paschale forms extensive mats in the most winter habitats of Rangifer tarandus populations in Norway. The plant communities accessible for grazing are often found on easily drained, moraine ridges. These lichen species are perennial, lying on the ground while growing slowly at the top. As they decompose they add humus to the top of the soil profile. The lichen mats catch all water from small showers, thus preventing vascular plants from obtaining a more regular water supply. Grazing removs whole plants and gradually makes larger and larger holes in the lichen mats. Wind and water erode the humus, with only coarse gravel remaining. This diminishes the soil water storage capacity. Without grazing, lichens will gradually build a humus layer, which would improve the soil water storage capacity. In time vascular plants then would take the place of the lichens. I propose the hypothesis that by (over-grazing Rangifer improve their winter pastures by making conditions more favourable for lichens than for vascular plants.The fact that lichens are more scarce on habitats with more and regular precipitation, 1 in more oceanic climates, 2 on soils with more silt, and 3 on bird perches with thick peat due to regular fertilising, support this hypothesis.

  1. Denis Burkitt and the origins of the dietary fibre hypothesis.

    Science.gov (United States)

    Cummings, John H; Engineer, Amanda

    2017-06-06

    For more than 200 years the fibre in plant foods has been known by animal nutritionists to have significant effects on digestion. Its role in human nutrition began to be investigated towards the end of the 19th century. However, between 1966 and 1972, Denis Burkitt, a surgeon who had recently returned from Africa, brought together ideas from a range of disciplines together with observations from his own experience to propose a radical view of the role of fibre in human health. Burkitt came late to the fibre story but built on the work of three physicians (Peter Cleave, G. D. Campbell and Hugh Trowell), a surgeon (Neil Painter) and a biochemist (Alec Walker) to propose that diets low in fibre increase the risk of CHD, obesity, diabetes, dental caries, various vascular disorders and large bowel conditions such as cancer, appendicitis and diverticulosis. Simply grouping these diseases together as having a common cause was groundbreaking. Proposing fibre as the key stimulated much research but also controversy. Credit for the dietary fibre hypothesis is given largely to Burkitt who became known as the 'Fibre Man'. This paper sets out the story of the development of the fibre hypothesis, and the contribution to it of these individuals.

  2. Synchronization and phonological skills: precise auditory timing hypothesis (PATH

    Directory of Open Access Journals (Sweden)

    Adam eTierney

    2014-11-01

    Full Text Available Phonological skills are enhanced by music training, but the mechanisms enabling this cross-domain enhancement remain unknown. To explain this cross-domain transfer, we propose a precise auditory timing hypothesis (PATH whereby entrainment practice is the core mechanism underlying enhanced phonological abilities in musicians. Both rhythmic synchronization and language skills such as consonant discrimination, detection of word and phrase boundaries, and conversational turn-taking rely on the perception of extremely fine-grained timing details in sound. Auditory-motor timing is an acoustic feature which meets all five of the pre-conditions necessary for cross-domain enhancement to occur (Patel 2011, 2012, 2014. There is overlap between the neural networks that process timing in the context of both music and language. Entrainment to music demands more precise timing sensitivity than does language processing. Moreover, auditory-motor timing integration captures the emotion of the trainee, is repeatedly practiced, and demands focused attention. The precise auditory timing hypothesis predicts that musical training emphasizing entrainment will be particularly effective in enhancing phonological skills.

  3. The delphic oracle and the ethylene-intoxication hypothesis.

    Science.gov (United States)

    Foster, J; Lehoux, D

    2007-01-01

    An interdisciplinary team of scientists--including an archeologist, a geologist, a chemist, and a toxicologist--has argued that ethylene intoxication was the probable cause of the High Priestess of Delphi's divinatory (mantic) trances. The claim that the High Priestess of Delphi entered a mantic state because of ethylene intoxication enjoyed widespread reception in specialist academic journals, science magazines, and newspapers. This article uses a similar interdisciplinary approach to show that this hypothesis is implausible since it is based on problematic scientific and textual evidence, as well as a fallacious argument. The main issue raised by this counterargument is not that a particular scientific hypothesis or conjecture turned out to be false. (This is expected in scientific investigation.) Rather, the main issue is that it was a positivist disposition that originally led readers to associate the evidence presented in such a way that it seemed to point to the conclusion, even when the evidence did not support the conclusion. We conclude by observing that positivist dispositions can lead to the acceptance of claims because they have a scientific form, not because they are grounded in robust evidence and sound argument.

  4. On the origins of autism: The Quantitative Threshold Exposure hypothesis.

    Science.gov (United States)

    Crawford, S

    2015-12-01

    The Quantitative Threshold Exposure (QTE) hypothesis is a multifactorial threshold model that accounts for the cumulative effects of risk factor exposure in both the causation of autism spectrum disorder (ASD) and its dramatic increase over the past 30 years. The QTE hypothesis proposes that ASD is triggered by the cumulative effects of high-level exposure to endogenous and environmental factors that act as antigens to impair normal immune system (IS) and associated central nervous system (CNS) functions during critical developmental stages. The quantitative threshold parameters that comprise a cumulative risk for the development of ASD are identified by the assessment of documented epidemiological factors that, in sum, determine the likelihood that ASD will occur as a result of their effects on critically integrated IS and CNS pathways active during prenatal, neo-natal and early childhood brain maturation. The model proposes an explanation for the relationship between critical developmental stages of brain/immune system development in conjunction with the quantitative effects of genetic and environmental risk factors that may interface with these critical developmental windows. This model may be useful even when the individual contributions of specific risk factors cannot be quantified, as it proposes that the combined quantitative level of exposure to risk factors for ASD rather than exposure to any one risk factor per se defines threshold occurrence rates. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Immigration, political trust, and Brexit - Testing an aversion amplification hypothesis.

    Science.gov (United States)

    Abrams, Dominic; Travaglino, Giovanni A

    2018-04-01

    A few weeks prior to the EU referendum (23rd June 2016) two broadly representative samples of the electorate were drawn in Kent (the south-east of England, N = 1,001) and Scotland (N = 1,088) for online surveys that measured their trust in politicians, concerns about acceptable levels of immigration, threat from immigration, European identification, and voting intention. We tested an aversion amplification hypothesis that the impact of immigration concerns on threat and identification would be amplified when political trust was low. We hypothesized that the effect of aversion amplification on voting intentions would be mediated first by perceived threat from immigration, and then by (dis) identification with Europe. Results in both samples were consistent with this hypothesis and suggest that voters were most likely to reject the political status quo (choose Brexit) when concerns that immigration levels were too high were combined with a low level of trust in politicians. © 2018 The Authors. British Journal of Social Psychology published by John Wiley & Sons Ltd on behalf of British Psychological Society.

  6. Analogical reasoning and aging: the processing speed and inhibition hypothesis.

    Science.gov (United States)

    Bugaiska, Aurélia; Thibaut, Jean-Pierre

    2015-01-01

    This study was designed to investigate the effect of aging on analogical reasoning by manipulating the strength of semantic association (LowAssoc or HighAssoc) and the number of distracters' semantic analogies of the A:B::C:D type and to determine which factors might be responsible for the age-related differences on analogical reasoning by testing two different theoretical frameworks: the inhibition hypothesis and the speed mediation hypothesis. We compared young adults and two groups of aging people (old and old-old) with word analogies of the A:B::C:D format. Results indicate an age-related effect on analogical reasoning, this effect being greatest with LowAssoc analogies. It was not associated with the presence of semantic distractors. Moreover, the results show that the variance part of the analogy task due to age was mainly explained by processing speed (rather than by inhibition) in the case of old participants and by both processing speed and inhibition in the old-old group. These results are discussed in relation to current models of aging and their interaction with the processes involved in analogical reasoning.

  7. Intraclutch variation in avian eggshell pigmentation: the anaemia hypothesis.

    Science.gov (United States)

    De Coster, Greet; De Neve, Liesbeth; Lens, Luc

    2012-10-01

    Many passerine species lay eggs that are speckled with dark protoporphyrin pigmentation. Because protoporphyrin is mainly derived from the blood, we here formulate and test a new hypothesis that links an increase in anaemia along the laying sequence to within-clutch variation in egg pigmentation. More intense pigmentation is expected if pigments accumulate during enhanced red blood cell production in response to anaemia. Reduced pigmentation is expected if pigments are derived from the degradation of red blood cells that circulate in smaller numbers due to blood loss. To test this hypothesis, we manipulated anaemia in great tit (Parus major) females by infesting the nests with hen fleas (Ceratophyllus gallinae) prior to egg laying. Polychromatophil (i.e., immature red blood cells) percentage, as a measure of blood cell production, was positively correlated with parasite load confirming that female great tits experienced stronger anaemia when infested with haematophagous parasites during egg laying. We found a positive relationship between spot darkness and laying order that weakened under high parasite load. This result suggests that anaemia in females due to blood-sucking parasites led to diminished protoporphyrin from disintegrated red blood cells and hence a decreased deposition of protoporphyrin. However, the overall increase in pigment darkness along the laying sequence suggests that pigments also accumulate by enhanced red blood cell production caused by anaemia due to egg production itself.

  8. Testing for Marshall-Lerner hypothesis: A panel approach

    Science.gov (United States)

    Azizan, Nur Najwa; Sek, Siok Kun

    2014-12-01

    The relationship between real exchange rate and trade balances are documented in many theories. One of the theories is the so-called Marshall-Lerner condition. In this study, we seek to test for the validity of Marshall-Lerner hypothesis, i.e. to reveal if the depreciation of real exchange rate leads to the improvement in trade balances. We focus our study in ASEAN-5 countries and their main trade partners of U.S., Japan and China. The dynamic panel data of pooled mean group (PMG) approach is used to detect the Marshall-Lerner hypothesis among ASEAN-5, between ASEAN-5 and U.S., between ASEAN-5 and Japan and between ASEAN-5 and China respectively. The estimation is based on the autoregressive Distributed Lag or ARDL model for the period of 1970-2012. The paper concludes that Marshal Lerner theory does not hold in bilateral trades in four groups of countries. The trade balances of ASEAN5 are mainly determined by the domestic income level and foreign production cost.

  9. Microbial biofilms and wound healing: an ecological hypothesis.

    Science.gov (United States)

    Krom, Bastiaan P; Oskam, Jacques

    2014-05-01

    Man has lived together with microbes for so long that we have become completely dependent on their presence. Most microbes reside in biofilms; structured communities encased in a protective matrix of biopolymers. Under healthy conditions, the microbial biofilm is in balance with itself (endo-balance) and with the host (exo-balance). Integrity of the skin is an important immunological function. Wounds go through a well-orchestrated series of healing steps. However, if for some reason healing times are extended, serious problems related to infection and homeostasis can develop. Based on recent advances in biofilm research and microbiological identification we discuss two hypotheses describing the role of microbial biofilms in chronic wound biology. The first hypothesis describes microbial biofilms as the cause of extended healing times. The second hypothesis is based on the host as cause of extended healing times and basically treats microbial biofilms as a logical consequence of failure to re-build the integrity of the skin. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  10. Testing the reproductive groundplan hypothesis in ants (Hymenoptera: Formicidae).

    Science.gov (United States)

    Pamminger, Tobias; Hughes, William O H

    2017-01-01

    The evolution of complex societies with obligate reproductive division of labor represents one of the major transitions in evolution. In such societies, functionally sterile individuals (workers) perform many of fitness-relevant behaviors including allomaternal ones, without getting any direct fitness benefits. The question of how such worker division of labor has evolved remains controversial. The reproductive groundplan hypothesis (RGPH) offers a powerful proximate explanation for this evolutionary leap. The RGPH argues that the conserved genetic and endocrinological networks regulating fitness-relevant behavior (e g. foraging and brood care) in their solitary ancestors have become decoupled from actual reproduction in the worker caste and now generate worker behavioral phenotypes. However, the empirical support for this hypothesis remains limited to a handful of species making its general validity uncertain. In this study, we combine data from the literature with targeted sampling of key species and apply phylogenetically controlled comparative analysis to investigate if the key prediction of the RGPH, namely an association between allomaternal behavior and an allomaternal physiological state holds in the largest and most species-rich clade of social insects, the ants. Our findings clearly support the RPGH as a general framework to understand the evolution of the worker caste and shed light on one of the major transition in evolutionary history. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  11. A hypothesis to explain childhood cancers near nuclear power plants

    International Nuclear Information System (INIS)

    Fairlie, Ian

    2014-01-01

    Over 60 epidemiological studies world-wide have examined cancer incidences in children near nuclear power plants (NPPs): most of them indicate leukemia increases. These include the 2008 KiKK study commissioned by the German Government which found relative risks (RR) of 1.6 in total cancers and 2.2 in leukemias among infants living within 5 km of all German NPPs. The KiKK study has retriggered the debate as to the cause(s) of these increased cancers. A suggested hypothesis is that the increased cancers arise from radiation exposures to pregnant women near NPPs. However any theory has to account for the >10,000 fold discrepancy between official dose estimates from NPP emissions and observed increased risks. An explanation may be that doses from spikes in NPP radionuclide emissions are significantly larger than those estimated by official models which are diluted through the use of annual averages. In addition, risks to embryos/fetuses are greater than those to adults and haematopoietic tissues appear more radiosensitive in embryos/fetuses than in newborn babies. The product of possible increased doses and possible increased risks per dose may provide an explanation. - Highlights: • Over 60 studies worldwide on increased cancers near nuclear power plants (NPPs). • German government KiKK study provides very strong evidence. • Hypothesis proposes cancers arise in pregnant women near NPPs. • Nuclide spikes during refuelling could result in increased exposures. • Explanation offered for discrepancy between small dose estimates and large risks

  12. More than genes: the advanced fetal programming hypothesis.

    Science.gov (United States)

    Hocher, Berthold

    2014-10-01

    Many lines of data, initial epidemiologic studies as well as subsequent extensive experimental studies, indicate that early-life events play a powerful role in influencing later suceptibility to certain chronic diseases. Such events might be over- or undernutrition, exposure to environmental toxins, but also changes in hormones, in particular stress hormones. Typically, those events are triggered by the environmental challenges of the mother. However, recent studies have shown that paternal environmental or nutritional factors affect the phenotype of the offspring as well. The maternal and paternal environmental factors act on the phenotype of the offspring via epigenetic modification of its genome. The advanced fetal programming hypothesis proposes an additional non-environmentally driven mechanism: maternal and also paternal genes may influence the maturating sperm, the oocyte, and later the embryo/fetus, leading to their epigenetic alteration. Thus, the observed phenotype of the offspring may be altered by maternal/paternal genes independent of the fetal genome. Meanwhile, several independent association studies in humans dealing with metabolic and neurological traits also suggest that maternal genes might affect the offspring phenotype independent of the transmission of that particular gene to the offspring. Considering the implications of this hypothesis, some conclusions drawn from transgenic or knockout animal models and based on the causality between a genetic alteration and a phenotype, need to be challenged. Possible implications for the development, diagnostic and therapy of human genetic diseases have to be investigated. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  13. A Highest Order Hypothesis Compatibility Test for Monocular SLAM

    Directory of Open Access Journals (Sweden)

    Edmundo Guerra

    2013-08-01

    Full Text Available Simultaneous Location and Mapping (SLAM is a key problem to solve in order to build truly autonomous mobile robots. SLAM with a unique camera, or monocular SLAM, is probably one of the most complex SLAM variants, based entirely on a bearing-only sensor working over six DOF. The monocular SLAM method developed in this work is based on the Delayed Inverse-Depth (DI-D Feature Initialization, with the contribution of a new data association batch validation technique, the Highest Order Hypothesis Compatibility Test, HOHCT. The Delayed Inverse-Depth technique is used to initialize new features in the system and defines a single hypothesis for the initial depth of features with the use of a stochastic technique of triangulation. The introduced HOHCT method is based on the evaluation of statistically compatible hypotheses and a search algorithm designed to exploit the strengths of the Delayed Inverse-Depth technique to achieve good performance results. This work presents the HOHCT with a detailed formulation of the monocular DI-D SLAM problem. The performance of the proposed HOHCT is validated with experimental results, in both indoor and outdoor environments, while its costs are compared with other popular approaches.

  14. Testing the "Mudball Earth" Hypothesis: Are Neoproterozoic Glacial Deposits Capped with Supraglacial Dust?

    Science.gov (United States)

    Goodman, J. C.; Alvim Lage, C.

    2014-12-01

    The Snowball Earth hypothesis has inspired several variants which may help to explain some of the great mysteries of the Neoproterozoic glaciations. One of these, the "Mudball Earth", proposes that as the Earth remained completely frozen for millions of years, a layer of dust accumulated on the ice surface. This dust layer would darken the planet, making it easier for the Earth to escape from the highly stable snowball climate state. This hypothesis is testable: after the ice melted at the end of a glacial era, this dust would sink to the bottom of the ocean, possibly forming a distinct clay, mud, or silt layer on the top of the glacial till deposits: this "clay drape" would then be covered by the cap carbonates that mark a return to warm climate. Sublimation and ice flow during the glacial episode should make this layer thicker at the equator and thinner or absent in the poles. Is this clay layer actually present in the rock record? Is it more prevalent at the paleoequator, as predicted? A clay drape has been noticed anecdotally, but no global survey has been done to date. We conducted a thorough literature review of all sites where Neoproterozoic glacial diamictites have been observed, identifying the type of rock that lies between the diamictite and the postglacial cap carbonate, when present, during both Sturtian and Marinoan glacial periods. Only a few publications identify a distinct clay/silt/mud layer that might represent weathered dust. These sites are not grouped by paleolatitude in any obvious way. With access only to published reports, we cannot determine whether such a layer is absent, went unreported, or was misinterpreted by us. With this work we hope to attract the attention of Neoproterozoic field geologists, inviting them to comment on the presence or absence of strata which could confirm or reject the "Mudball" hypothesis.

  15. Sexual orientation, fraternal birth order, and the maternal immune hypothesis: a review.

    Science.gov (United States)

    Bogaert, Anthony F; Skorska, Malvina

    2011-04-01

    In 1996, psychologists Ray Blanchard and Anthony Bogaert found evidence that gay men have a greater number of older brothers than do heterosexual men. This "fraternal birth order" (FBO) effect has been replicated numerous times, including in non-Western samples. More recently, strong evidence has been found that the FBO effect is of prenatal origin. Although there is no direct support for the exact prenatal mechanism, the most plausible explanation may be immunological in origin, i.e., a mother develops an immune reaction against a substance important in male fetal development during pregnancy, and that this immune effect becomes increasingly likely with each male gestation. This immune effect is hypothesized to cause an alteration in (some) later born males' prenatal brain development. The target of the immune response may be molecules (i.e., Y-linked proteins) on the surface of male fetal brain cells, including in sites of the anterior hypothalamus, which has been linked to sexual orientation in other research. Antibodies might bind to these molecules and thus alter their role in typical sexual differentiation, leading some later born males to be attracted to men as opposed to women. Here we review evidence in favor of this hypothesis, including recent research showing that mothers of boys develop an immune response to one Y-linked protein (i.e., H-Y antigen; SMCY) important in male fetal development, and that this immune effect becomes increasingly likely with each additional boy to which a mother gives birth. We also discuss other Y-linked proteins that may be relevant if this hypothesis is correct. Finally, we discuss issues in testing the maternal immune hypothesis of FBO. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. The direct perception hypothesis: perceiving the intention of another’s action hinders its precise imitation

    Science.gov (United States)

    Froese, Tom; Leavens, David A.

    2014-01-01

    We argue that imitation is a learning response to unintelligible actions, especially to social conventions. Various strands of evidence are converging on this conclusion, but further progress has been hampered by an outdated theory of perceptual experience. Comparative psychology continues to be premised on the doctrine that humans and non-human primates only perceive others’ physical “surface behavior,” while mental states are perceptually inaccessible. However, a growing consensus in social cognition research accepts the direct perception hypothesis: primarily we see what others aim to do; we do not infer it from their motions. Indeed, physical details are overlooked – unless the action is unintelligible. On this basis we hypothesize that apes’ propensity to copy the goal of an action, rather than its precise means, is largely dependent on its perceived intelligibility. Conversely, children copy means more often than adults and apes because, uniquely, much adult human behavior is completely unintelligible to unenculturated observers due to the pervasiveness of arbitrary social conventions, as exemplified by customs, rituals, and languages. We expect the propensity to imitate to be inversely correlated with the familiarity of cultural practices, as indexed by age and/or socio-cultural competence. The direct perception hypothesis thereby helps to parsimoniously explain the most important findings of imitation research, including children’s over-imitation and other species-typical and age-related variations. PMID:24600413

  17. Graphic tests of Easterlin's hypothesis: science or art?

    Science.gov (United States)

    Rutten, A; Higgs, R

    1984-01-01

    Richard Easterlin believes that the postwar fertility cycle is uniquely consistent with the hypothesis of his relative income model of fertility, yet a closer examination of his evidence shows that the case for the relative income explanation is much weaker than initially appears. Easterlin finds the postwar baby boom a transparent event. Couples who entered the labor market in the postwar period have very low material aspirations. Having grown up during the Great Depression and World War II, they were content with a modest level of living. Their labor market experience was very good. Tight restrictions on immigration kept aliens from coming in to fill the gap. Thus the members of his generation occupied an unprecedented position. They could easily meet and even exceed their expectations. This high level of relative income meant that they could have more of everything they wanted, including children. For the children born during the baby boom, all this was reversed, and hence the needs of the baby bust were sown. To test this hypothesis, Easterlin compared the movements of relative income and fertility over the postwar years using a graph. 4 published versions of the graph are presented. The graph shows that relative income and fertility did move together over the cycle, apparently very closely. Easterlin's measure of fertility is the total fertility rate (TFR). There is no such direct measure of relative income. Easterlin develops 2 proxies based on changing economic conditions believed to shape the level of material aspirations. His preferred measure, labeled R or income in his graph, relates the income experience of young couples in the years previous to marriage to that of their parents in the years before the young people left home. Because of the available data limit construction of this index to the years after 1956, another measure, labeled Re or employment in Easterlin's graphs, is constructed for the pre-1956 period. This measure relates the average of

  18. Birth order and fratricide: an evaluation of Sulloway's hypothesis.

    Science.gov (United States)

    Marleau, Jacques D

    2005-01-01

    Sulloway (1996) suggested that older siblings were more likely to be fratricidal than younger ones. Our data, based on 113 case studies found in the psychiatric, psychological and criminological literature since 1959, confirms his hypothesis. In 72 out of the 92 cases (78%) where age could be determined, the aggressor was older than the victim. The same held true even when the age of aggressor, sex of aggressor and victim, presence or not of a blood tie, and presence of one or more victims are taken into account. Surprisingly, most of the aggressors in our sample were under the age of 18 years. Also, first-borns were more often the aggressor than the victim. This result seems to confirm the Adlerian theory of dethronement. Some suggestions and hypotheses are advanced for future research to improve our understanding of this phenomenon.

  19. The General Motor Ability Hypothesis: An Old Idea Revisited.

    Science.gov (United States)

    Hands, Beth; McIntyre, Fleur; Parker, Helen

    2018-04-01

    While specific motor abilities have become a popular explanation for motor performance, the older, alternate notion of a general motor ability should be revisited. Current theories lack consensus, and most motor assessment tools continue to derive a single composite score to represent motor capacity. In addition, results from elegant statistical procedures such as higher order factor analyses, cluster analyses, and Item Response Theory support a more global motor ability. We propose a contemporary model of general motor ability as a unidimensional construct that is emergent and fluid over an individual's lifespan, influenced by both biological and environmental factors. In this article, we address the implications of this model for theory, practice, assessment, and research. Based on our hypothesis and Item Response Theory, our Lifespan Motor Ability Scale can identify motor assessment tasks that are relevant and important across varied phases of lifespan development.

  20. The intense world syndrome--an alternative hypothesis for autism

    DEFF Research Database (Denmark)

    Markram, Henry; Rinaldi, Tania; Markram, Kamila

    2007-01-01

    Autism is a devastating neurodevelopmental disorder with a polygenetic predisposition that seems to be triggered by multiple environmental factors during embryonic and/or early postnatal life. While significant advances have been made in identifying the neuronal structures and cells affected......, a unifying theory that could explain the manifold autistic symptoms has still not emerged. Based on recent synaptic, cellular, molecular, microcircuit, and behavioral results obtained with the valproic acid (VPA) rat model of autism, we propose here a unifying hypothesis where the core pathology...... of the autistic brain is hyper-reactivity and hyper-plasticity of local neuronal circuits. Such excessive neuronal processing in circumscribed circuits is suggested to lead to hyper-perception, hyper-attention, and hyper-memory, which may lie at the heart of most autistic symptoms. In this view, the autistic...

  1. Inflammation and the Two-Hit Hypothesis of Schizophrenia

    Science.gov (United States)

    Feigenson, Keith A.; Kusnecov, Alex W.; Silverstein, Steven M.

    2014-01-01

    The high societal and individual cost of schizophrenia necessitates finding better, more effective treatment, diagnosis, and prevention strategies. One of the obstacles in this endeavor is the diverse set of etiologies that comprises schizophrenia. A substantial body of evidence has grown over the last few decades to suggest that schizophrenia is a heterogeneous syndrome with overlapping symptoms and etiologies. At the same time, an increasing number of clinical, epidemiological, and experimental studies have shown links between schizophrenia and inflammatory conditions. In this review, we analyze the literature on inflammation and schizophrenia, with a particular focus on comorbidity, biomarkers, and environmental insults. We then identify several mechanisms by which inflammation could influence the development of schizophrenia via the two-hit hypothesis. Lastly, we note the relevance of these findings to clinical applications in the diagnosis, prevention, and treatment of schizophrenia. PMID:24247023

  2. Mirror neurons, birdsong, and human language: a hypothesis.

    Science.gov (United States)

    Levy, Florence

    2011-01-01

    THE MIRROR SYSTEM HYPOTHESIS AND INVESTIGATIONS OF BIRDSONG ARE REVIEWED IN RELATION TO THE SIGNIFICANCE FOR THE DEVELOPMENT OF HUMAN SYMBOLIC AND LANGUAGE CAPACITY, IN TERMS OF THREE FUNDAMENTAL FORMS OF COGNITIVE REFERENCE: iconic, indexical, and symbolic. Mirror systems are initially iconic but can progress to indexical reference when produced without the need for concurrent stimuli. Developmental stages in birdsong are also explored with reference to juvenile subsong vs complex stereotyped adult syllables, as an analogy with human language development. While birdsong remains at an indexical reference stage, human language benefits from the capacity for symbolic reference. During a pre-linguistic "babbling" stage, recognition of native phonemic categories is established, allowing further development of subsequent prefrontal and linguistic circuits for sequential language capacity.

  3. Mirror neurons, birdsong and human language: a hypothesis

    Directory of Open Access Journals (Sweden)

    Florence eLevy

    2012-01-01

    Full Text Available AbstractThe Mirror System Hypothesis (MSH and investigations of birdsong are reviewed in relation to the significance for the development of human symbolic and language capacity, in terms of three fundamental forms of cognitive reference: iconic, indexical, and symbolic. Mirror systems are initially iconic but can progress to indexal reference when produced without the need for concurrent stimuli. Developmental stages in birdsong are also explored with reference to juvenile subsong vs complex stereotyped adult syllables, as an analogy with human language development. While birdsong remains at an indexal reference stage, human language benefits from the capacity for symbolic reference. During a pre-linguistic ‘babbling’ stage, recognition of native phonemic categories is established, allowing further development of a subsequent prefrontal and linguistic circuits for sequential language capacity.

  4. Neurobiological hypothesis of color appearance and hue perception.

    Science.gov (United States)

    Schmidt, Brian P; Neitz, Maureen; Neitz, Jay

    2014-04-01

    De Valois and De Valois [Vis. Res.33, 1053 (1993)] showed that to explain hue appearance, S-cone signals have to be combined with M versus L opponent signals in two different ways to produce red-green and yellow-blue axes, respectively. Recently, it has been shown that color appearance is normal for individuals with genetic mutations that block S-cone input to blue-ON ganglion cells. This is inconsistent with the De Valois hypothesis in which S-opponent konio-geniculate signals are combined with L-M signals at a third processing stage in cortex. Instead, here we show that color appearance, including individual differences never explained before, are predicted by a model in which S-cone signals are combined with L versus M signals in the outer retina.

  5. Hypothesis testing approaches to the exon prediction problem.

    Science.gov (United States)

    Vilardell, Mireia; Sánchez-Pla, Alex

    2006-12-15

    Many gene identification methods assign scores to gene elements prior to their assembly into predicted genes. The scoring system is often based on log-likelihood ratios. These methods usually perform well but it is difficult to interpret how significant a score is. We have developed several tests of significance for the scores: (1) a sum-of-scores test (SST), (2) an intersection-union test (IUT), based on a multiple hypothesis testing interpretation of an exon's score and (3) a meta-analytical approach (MA), which combines several P-values, corresponding to the exon's parts, to yield a global P-value. We performed simulation studies, which show that the MA has better sensitivity and specificity than other methods and is easier to interpret by non-expert users. This is an improvement over other methods and is especially relevant for users who would like to predict incomplete gene sequences.

  6. Ten Challenges of the Amyloid Hypothesis of Alzheimer's Disease.

    Science.gov (United States)

    Kepp, Kasper Planeta

    2017-01-01

    The inability to effectively halt or cure Alzheimer's disease (AD), exacerbated by the recent failures of high-profile clinical trials, emphasizes the urgent need to understand the complex biochemistry of this major neurodegenerative disease. In this paper, ten central, current challenges of the major paradigm in the field, the amyloid hypothesis, are sharply formulated. These challenges together show that new approaches are necessary that address data heterogeneity, increase focus on the proteome level, use available human patient data more actively, account for the aging phenotype as a background model of the disease, unify our understanding of the interplay between genetic and non-genetic risk factors, and combine into one framework both the familial and sporadic forms of the disease.

  7. A new hypothesis of dinosaur relationships and early dinosaur evolution.

    Science.gov (United States)

    Baron, Matthew G; Norman, David B; Barrett, Paul M

    2017-03-22

    For 130 years, dinosaurs have been divided into two distinct clades-Ornithischia and Saurischia. Here we present a hypothesis for the phylogenetic relationships of the major dinosaurian groups that challenges the current consensus concerning early dinosaur evolution and highlights problematic aspects of current cladistic definitions. Our study has found a sister-group relationship between Ornithischia and Theropoda (united in the new clade Ornithoscelida), with Sauropodomorpha and Herrerasauridae (as the redefined Saurischia) forming its monophyletic outgroup. This new tree topology requires redefinition and rediagnosis of Dinosauria and the subsidiary dinosaurian clades. In addition, it forces re-evaluations of early dinosaur cladogenesis and character evolution, suggests that hypercarnivory was acquired independently in herrerasaurids and theropods, and offers an explanation for many of the anatomical features previously regarded as notable convergences between theropods and early ornithischians.

  8. The Role of Hypothesis in Constructive Design Research

    DEFF Research Database (Denmark)

    Bang, Anne Louise; Krogh, Peter; Ludvigsen, Martin

    2012-01-01

    It is, today, widely appreciated that Research-through-Design – or Constructive Design Research as we will call it in this paper – allows for designers to produce knowledge based on the skills and capacities of the design field itself. However, most of the research fails to bridge the gap between...... the general notions of constructive design research and the detailed research activities of the field. We therefore suggest bridging this methodological gap in the academic discussion with what we have ended up calling the “entrance level of constructive design research”. As a step towards to a more nuanced...... and solid perspective on how to keep constructive design research on track, this paper offers a model for understanding the role of hypothesis in constructive design research. The model allows for understanding the hypothesis’s relation to research motivation, questions, experiments, evaluation...

  9. Chi-square test and its application in hypothesis testing

    Directory of Open Access Journals (Sweden)

    Rakesh Rana

    2015-01-01

    Full Text Available In medical research, there are studies which often collect data on categorical variables that can be summarized as a series of counts. These counts are commonly arranged in a tabular format known as a contingency table. The chi-square test statistic can be used to evaluate whether there is an association between the rows and columns in a contingency table. More specifically, this statistic can be used to determine whether there is any difference between the study groups in the proportions of the risk factor of interest. Chi-square test and the logic of hypothesis testing were developed by Karl Pearson. This article describes in detail what is a chi-square test, on which type of data it is used, the assumptions associated with its application, how to manually calculate it and how to make use of an online calculator for calculating the Chi-square statistics and its associated P-value.

  10. Persistent Confusions about Hypothesis Testing in the Social Sciences

    Directory of Open Access Journals (Sweden)

    Christopher Thron

    2015-05-01

    Full Text Available This paper analyzes common confusions involving basic concepts in statistical hypothesis testing. One-third of the social science statistics textbooks examined in the study contained false statements about significance level and/or p-value. We infer that a large proportion of social scientists are being miseducated about these concepts. We analyze the causes of these persistent misunderstandings, and conclude that the conventional terminology is prone to abuse because it does not clearly represent the conditional nature of probabilities and events involved. We argue that modifications in terminology, as well as the explicit introduction of conditional probability concepts and notation into the statistics curriculum in the social sciences, are necessary to prevent the persistence of these errors.

  11. The source dilemma hypothesis: Perceptual uncertainty contributes to musical emotion.

    Science.gov (United States)

    Bonin, Tanor L; Trainor, Laurel J; Belyk, Michel; Andrews, Paul W

    2016-09-01

    Music can evoke powerful emotions in listeners. Here we provide the first empirical evidence that the principles of auditory scene analysis and evolutionary theories of emotion are critical to a comprehensive theory of musical emotion. We interpret these data in light of a theoretical framework termed "the source dilemma hypothesis," which predicts that uncertainty in the number, identity or location of sound objects elicits unpleasant emotions by presenting the auditory system with an incoherent percept, thereby motivating listeners to resolve the auditory ambiguity. We describe two experiments in which source location and timbre were manipulated to change uncertainty in the auditory scene. In both experiments, listeners rated tonal and atonal melodies with congruent auditory scene cues as more pleasant than melodies with incongruent auditory scene cues. These data suggest that music's emotive capacity relies in part on the perceptual uncertainty it produces regarding the auditory scene. Copyright © 2016. Published by Elsevier B.V.

  12. Imaging of Ventricular Fibrillation and Defibrillation: The Virtual Electrode Hypothesis.

    Science.gov (United States)

    Boukens, Bastiaan J; Gutbrod, Sarah R; Efimov, Igor R

    2015-01-01

    Ventricular fibrillation is the major underlying cause of sudden cardiac death. Understanding the complex activation patterns that give rise to ventricular fibrillation requires high resolution mapping of localized activation. The use of multi-electrode mapping unraveled re-entrant activation patterns that underlie ventricular fibrillation. However, optical mapping contributed critically to understanding the mechanism of defibrillation, where multi-electrode recordings could not measure activation patterns during and immediately after a shock. In addition, optical mapping visualizes the virtual electrodes that are generated during stimulation and defibrillation pulses, which contributed to the formulation of the virtual electrode hypothesis. The generation of virtual electrode induced phase singularities during defibrillation is arrhythmogenic and may lead to the induction of fibrillation subsequent to defibrillation. Defibrillating with low energy may circumvent this problem. Therefore, the current challenge is to use the knowledge provided by optical mapping to develop a low energy approach of defibrillation, which may lead to more successful defibrillation.

  13. Brain Evolution and Human Neuropsychology: The Inferential Brain Hypothesis

    Science.gov (United States)

    Koscik, Timothy R.; Tranel, Daniel

    2013-01-01

    Collaboration between human neuropsychology and comparative neuroscience has generated invaluable contributions to our understanding of human brain evolution and function. Further cross-talk between these disciplines has the potential to continue to revolutionize these fields. Modern neuroimaging methods could be applied in a comparative context, yielding exciting new data with the potential of providing insight into brain evolution. Conversely, incorporating an evolutionary base into the theoretical perspectives from which we approach human neuropsychology could lead to novel hypotheses and testable predictions. In the spirit of these objectives, we present here a new theoretical proposal, the Inferential Brain Hypothesis, whereby the human brain is thought to be characterized by a shift from perceptual processing to inferential computation, particularly within the social realm. This shift is believed to be a driving force for the evolution of the large human cortex. PMID:22459075

  14. Failure of the statistical hypothesis for compound nucleus decay

    International Nuclear Information System (INIS)

    Chrien, R.E.

    1976-01-01

    In the past five years, conclusive evidence has accumulated that channel correlations are important in resonance reactions. Experiments showing the failure of the statistical hypothesis for compound nucleus decay are described. The emphasis is on the radiative neutron capture reaction, where much detailed work has been done. A short summary of the theory of the (n,γ) reaction is presented; it is demonstrated that this reaction is a sensitive probe of the wave functions for highly excited nuclear states. Various experimental techniques using reactor and accelerator-based neutron sources are presented. The experiments have shown that both resonant and non-resonant reactions can show single particle effects where the external part of configuration space is dominant. In the non-resonant case, hard sphere capture is important; on resonances, valence particle motion and the contributions of 1 and 3 quasi-particle doorway states make up a significant fraction of the radiative width

  15. Perspective: Structural fluctuation of protein and Anfinsen's thermodynamic hypothesis

    Science.gov (United States)

    Hirata, Fumio; Sugita, Masatake; Yoshida, Masasuke; Akasaka, Kazuyuki

    2018-01-01

    The thermodynamics hypothesis, casually referred to as "Anfinsen's dogma," is described theoretically in terms of a concept of the structural fluctuation of protein or the first moment (average structure) and the second moment (variance and covariance) of the structural distribution. The new theoretical concept views the unfolding and refolding processes of protein as a shift of the structural distribution induced by a thermodynamic perturbation, with the variance-covariance matrix varying. Based on the theoretical concept, a method to characterize the mechanism of folding (or unfolding) is proposed. The transition state, if any, between two stable states is interpreted as a gap in the distribution, which is created due to an extensive reorganization of hydrogen bonds among back-bone atoms of protein and with water molecules in the course of conformational change. Further perspective to applying the theory to the computer-aided drug design, and to the material science, is briefly discussed.

  16. Etiology of common childhood acute lymphoblastic leukemia: the adrenal hypothesis

    DEFF Research Database (Denmark)

    Schmiegelow, K.; Vestergaard, T.; Nielsen, S.M.

    2008-01-01

    The pattern of infections in the first years of life modulates our immune system, and a low incidence of infections has been linked to an increased risk of common childhood acute lymphoblastic leukemia (ALL). We here present a new interpretation of these observations--the adrenal hypothesis......--that proposes that the risk of childhood ALL is reduced when early childhood infections induce qualitative and quantitative changes in the hypothalamus-pituitary-adrenal axis that increase plasma cortisol levels. This may directly eliminate leukemic cells as well as preleukemic cells for the ALL subsets...... that dominate in the first 5-7 years of life and may furthermore suppress the Th1-dominated proinflammatory response to infections, and thus lower the proliferative stress on pre-existing preleukemic cells Udgivelsesdato: 2008/12...

  17. Independent component analysis in non-hypothesis driven metabolomics

    DEFF Research Database (Denmark)

    Li, Xiang; Hansen, Jakob; Zhao, Xinjie

    2012-01-01

    components were involved in fuel metabolism, representing one of the most affected metabolic changes occurring in exercising humans. Conclusive time dependent physiological changes of the metabolic pattern under exercise conditions were detected. We conclude that after optimization ICA can successfully......In a non-hypothesis driven metabolomics approach plasma samples collected at six different time points (before, during and after an exercise bout) were analyzed by gas chromatography-time of flight mass spectrometry (GC-TOF MS). Since independent component analysis (ICA) does not need a priori...... information on the investigated process and moreover can separate statistically independent source signals with non-Gaussian distribution, we aimed to elucidate the analytical power of ICA for the metabolic pattern analysis and the identification of key metabolites in this exercise study. A novel approach...

  18. Planned Hypothesis Tests Are Not Necessarily Exempt From Multiplicity Adjustment

    Directory of Open Access Journals (Sweden)

    Andrew V. Frane

    2015-10-01

    Full Text Available Scientific research often involves testing more than one hypothesis at a time, which can inflate the probability that a Type I error (false discovery will occur. To prevent this Type I error inflation, adjustments can be made to the testing procedure that compensate for the number of tests. Yet many researchers believe that such adjustments are inherently unnecessary if the tests were “planned” (i.e., if the hypotheses were specified before the study began. This longstanding misconception continues to be perpetuated in textbooks and continues to be cited in journal articles to justify disregard for Type I error inflation. I critically evaluate this myth and examine its rationales and variations. To emphasize the myth’s prevalence and relevance in current research practice, I provide examples from popular textbooks and from recent literature. I also make recommendations for improving research practice and pedagogy regarding this problem and regarding multiple testing in general.

  19. Multitask Classification Hypothesis Space With Improved Generalization Bounds.

    Science.gov (United States)

    Li, Cong; Georgiopoulos, Michael; Anagnostopoulos, Georgios C

    2015-07-01

    This paper presents a pair of hypothesis spaces (HSs) of vector-valued functions intended to be used in the context of multitask classification. While both are parameterized on the elements of reproducing kernel Hilbert spaces and impose a feature mapping that is common to all tasks, one of them assumes this mapping as fixed, while the more general one learns the mapping via multiple kernel learning. For these new HSs, empirical Rademacher complexity-based generalization bounds are derived, and are shown to be tighter than the bound of a particular HS, which has appeared recently in the literature, leading to improved performance. As a matter of fact, the latter HS is shown to be a special case of ours. Based on an equivalence to Group-Lasso type HSs, the proposed HSs are utilized toward corresponding support vector machine-based formulations. Finally, experimental results on multitask learning problems underline the quality of the derived bounds and validate this paper's analysis.

  20. Outdoor Ambient Air Pollution and Neurodegenerative Diseases: the Neuroinflammation Hypothesis.

    Science.gov (United States)

    Jayaraj, Richard L; Rodriguez, Eric A; Wang, Yi; Block, Michelle L

    2017-06-01

    Accumulating research indicates that ambient outdoor air pollution impacts the brain and may affect neurodegenerative diseases, yet the potential underlying mechanisms are poorly understood. The neuroinflammation hypothesis holds that elevation of cytokines and reactive oxygen species in the brain mediates the deleterious effects of urban air pollution on the central nervous system (CNS). Studies in human and animal research document that neuroinflammation occurs in response to several inhaled pollutants. Microglia are a prominent source of cytokines and reactive oxygen species in the brain, implicated in the progressive neuron damage in diverse neurodegenerative diseases, and activated by inhaled components of urban air pollution through both direct and indirect pathways. The MAC1-NOX2 pathway has been identified as a mechanism through which microglia respond to different forms of air pollution, suggesting a potential common deleterious pathway. Multiple direct and indirect pathways in response to air pollution exposure likely interact in concert to exert CNS effects.

  1. A hypothesis of coevolution between cooperation and responses to inequity

    Directory of Open Access Journals (Sweden)

    Sarah F Brosnan

    2011-04-01

    Full Text Available Recent evidence demonstrates that humans are not the only species to respond negatively to inequitable outcomes which are to their disadvantage. Several species respond negatively if they subsequently receive a less good reward than a social partner for completing the same task. While these studies suggest that the negative response to inequity is not a uniquely human behavior, they do not provide a functional explanation for the emergence of these responses due to similar characteristics among these species. Emerging data support the hypothesis that an aversion to inequity is a mechanism to promote successful long-term cooperative relationships amongst non-kin. In this paper, I discuss several converging lines of evidence which illustrate the need to further evaluate this relationship. First, cooperation can survive modest inequity; in explicitly cooperative interactions, individuals are willing to continue to cooperate despite inequitable outcomes as long as the partner’s overall behavior is equitable. Second, the context of inequity affects reactions to it in ways which support the idea that joint efforts lead to an expectation of joint payoffs. Finally, comparative studies indicate a link between the degree and extent of cooperation between unrelated individuals in a species and that species’ response to inequitable outcomes. This latter line of evidence indicates that this behavior evolved in conjunction with cooperation and may represent an adaptation to increase the payoffs associated with cooperative interactions. Together these data inform a testable working hypothesis for understanding decision-making in the context of inequity and provide a new, comparative framework for evaluating decision-making behavior.

  2. Seeing via miniature eye movements: A dynamic hypothesis for vision

    Directory of Open Access Journals (Sweden)

    Ehud eAhissar

    2012-11-01

    Full Text Available During natural viewing, the eyes are never still. Even during fixation, miniature movements of the eyes move the retinal image across tens of foveal photoreceptors. Most theories of vision implicitly assume that the visual system ignores these movements and somehow overcomes the resulting smearing. However, evidence has accumulated to indicate that fixational eye movements cannot be ignored by the visual system if fine spatial details are to be resolved. We argue that the only way the visual system can achieve its high resolution given its fixational movements is by seeing via these movements. Seeing via eye movements also eliminates the instability of the image, which would be induced by them otherwise. Here we present a hypothesis for vision, in which coarse details are spatially-encoded in gaze-related coordinates, and fine spatial details are temporally-encoded in relative retinal coordinates. The temporal encoding presented here achieves its highest resolution by encoding along the elongated axes of simple cell receptive fields and not across these axes as suggested by spatial models of vision. According to our hypothesis, fine details of shape are encoded by inter-receptor temporal phases, texture by instantaneous intra-burst rates of individual receptors, and motion by inter-burst temporal frequencies. We further describe the ability of the visual system to readout the encoded information and recode it internally. We show how reading out of retinal signals can be facilitated by neuronal phase-locked loops (NPLLs, which lock to the retinal jitter; this locking enables recoding of motion information and temporal framing of shape and texture processing. A possible implementation of this locking-and-recoding process by specific thalamocortical loops is suggested. Overall it is suggested that high-acuity vision is based primarily on temporal mechanisms of the sort presented here and low-acuity vision is based primarily on spatial mechanisms.

  3. The CoRR hypothesis for genes in organelles.

    Science.gov (United States)

    Allen, John F

    2017-12-07

    Chloroplasts and mitochondria perform energy transduction in photosynthesis and respiration. These processes can be described in physico-chemical terms with no obvious requirement for co-located genetic systems, separat from those of the rest of the cell. Accordingly, biochemists once tended to regard endosymbiosis as untestable evolutionary speculation. Lynn Sagan's seminal 1967 paper "On the Origin of Mitosing Cells" outlined the evolution of eukaryotic cells by endosymbiosis of prokaryotes. The endosymbiont hypothesis is consistent with presence of DNA in chloroplasts and mitochondria, but does not assign it a function. Biochemistry and molecular biology now show that Sagan's proposal has an explanatory reach far beyond that originally envisaged. Prokaryotic origins of photosynthetic and respiratory mechanisms are apparent in protein structural insights into energy coupling. Genome sequencing confirms the underlying, prokaryotic architecture of chloroplasts and mitochondria and illustrates the profound influence of the original mergers of their ancestors' genes and proteins with those of their host cells. Peter Mitchell's 1961 chemiosmotic hypothesis applied the concept of vectorial catalysis that underlies biological energy transduction and cell structure, function, and origins. Continuity of electrical charge separation and membrane sidedness requires compartments within compartments, together with intricate mechanisms for transport within and between them. I suggest that the reason for the persistence of distinct genetic systems within bioenergetic organelles is the selective advantage of subcellular co-location of specific genes with their gene products. Co-location for Redox Regulation - CoRR - provides for a dialogue between chemical reduction-oxidation and the action of genes encoding its protein catalysts. These genes and their protein products are in intimate contact, and cannot be isolated from each other without loss of an essential mechanism of

  4. Mefloquine use, psychosis, and violence: a retinoid toxicity hypothesis.

    Science.gov (United States)

    Mawson, Anthony

    2013-07-15

    Mefloquine use has been linked to severe gastrointestinal and neuropsychiatric adverse effects, including cognitive disturbances, anxiety, depression, psychosis, and violence. The adverse effects of the drug are thought to result from the secondary consequences of hepatocellular injury; in fact, mefloquine is known to cause a transient, anicteric chemical hepatitis. However, the mechanism of mefloquine-associated liver damage and the associated neuropsychiatric and behavioral effects of the drug are not well understood. Mefloquine and other 8-amino-quinolines are the only antimalarial drugs that target the liver-stage malaria parasites, which selectively absorb vitamin A from the host. Vitamin A is also stored mainly in the liver, in potentially poisonous concentrations. These observations suggest that both the therapeutic effectiveness of mefloquine and its adverse effects are related to the ability of the 8-aminoquinolines to alter the metabolism of retinoids (vitamin A and its congeners). Several lines of evidence support the hypothesis that mefloquine neurotoxicity and other adverse effects reflect an endogenous form of hypervitaminosis A due to a process involving: mefloquine-induced dehydrogenase inhibition; the accumulation of retinoids in the liver; retinoid-induced hepatocellular damage; the spillage of stored retinoids into the circulation; and the transport of these compounds to the gut and brain in toxic concentrations. The retinoid hypothesis could be tested clinically by comparing cases of mefloquine toxicity and untreated controls in terms of retinoid profiles (retinol, retinyl esters, percent retinyl esters, and retinoic acid). Subject to such tests, retinoid profiling could provide an indicator for assessing mefloquine-associated adverse effects.

  5. Lynn White Jr. and the greening-of-religion hypothesis.

    Science.gov (United States)

    Taylor, Bron; Van Wieren, Gretel; Zaleha, Bernard Daley

    2016-10-01

    Lynn White Jr.'s "The Historical Roots of Our Ecologic Crisis," which was published in Science in 1967, has played a critical role in precipitating interdisciplinary environmental studies. Although White advances a multifaceted argument, most respondents focus on his claim that the Judeo-Christian tradition, especially Christianity, has promoted anthropocentric attitudes and environmentally destructive behaviors. Decades later, some scholars argue contrarily that Christianity in particular and the world's predominant religions in general are becoming more environmentally friendly, known as the greening-of-religion hypothesis. To test these claims, we conducted a comprehensive review of over 700 articles-historical, qualitative, and quantitative-that are pertinent to them. Although definitive conclusions are difficult, we identified many themes and dynamics that hinder environmental understanding and mobilization, including conservative theological orientations and beliefs about the role of divine agency in preventing or promoting natural events, whether the religion is an Abrahamic tradition or originated in Asia. On balance, we found the thrust of White's thesis is supported, whereas the greening-of-religion hypothesis is not. We also found that indigenous traditions often foster proenvironmental perceptions. This finding suggests that indigenous traditions may be more likely to be proenvironmental than other religious systems and that some nature-based cosmologies and value systems function similarly. Although we conclude White's thesis and subsequent claims are largely born out, additional research is needed to better understand under what circumstances and communication strategies religious or other individuals and groups may be more effectively mobilized to respond to contemporary environmental challenges. © 2016 Society for Conservation Biology.

  6. Somatic mutation, a cause of biliary atresia: A hypothesis.

    Science.gov (United States)

    Fabre, Alexandre; Roman, Céline; Roquelaure, Bertrand

    2017-05-01

    Despite many years of research, the causes of biliary atresia still remain elusive. Infection, immune disorder, toxins or maternal microchimerism have been cited as potential triggers of biliary atresia. This is a rare disease with a stable incidence over the years although with sizeable ethnic variations. This stability suggests that environmental factors have in fact only a slight influence. During the search for etiologies, twin studies have often helped disentangle the genetic from the environmental. For this condition, twin studies have mainly demonstrated a lack of concordance between twins (either monozygotic or dizygotic), ruling out Mendelian, infectious or toxic causes. Indeed, for toxic or infectious embryopathy, the concordance for twins (especially monozygotic) is about 80%. Paradoxically, these data suggest that biliary atresia has neither a genetic nor an environmental cause. One way of severing the Gordian knot is to hypothesize a role for post zygotic somatic mutation, leading to genetic mosaicism (as a cause of biliary atresia). In recent years, post zygotic mutation has been identified as a cause of non-cancerous disease ranging from dysmorphic syndrome to specific organ abnormalities. A potential model for this condition could be post zygotic mutation or copy number variations in genes or regulatory regions, triggering the cascade of events leading to inflammatory and obliterative cholangiopathy. These events could be enhanced by genetic susceptibility explaining the ethnic variations. In these models, the rate of mosaicism in different parts of the liver could explain the success rate of the Kasai procedure. This hypothesis can be tested: as most children with biliary atresia are eligible for the Kasai procedure, genetic material from the liver and ductal plate can be collected easily. If the hypothesis is correct, whole genome sequencing or copy number variation studies at individual cell level should allow to identify the expected low level

  7. The minimum transition hypothesis for intermittent hierarchical motor control

    Directory of Open Access Journals (Sweden)

    Amir eKarniel

    2013-02-01

    Full Text Available In intermittent control, instead of continuously calculating the control signal, the controller occasionally changes this signal at certain sparse points in time. The control law may include feedback, adaptation, optimization, or any other control strategies. When, where, and how does the brain employ intermittency as it controls movement? These are open questions in motor neuroscience. Evidence for intermittency in human motor control has been repeatedly observed in the neural control of movement literature. Moreover, some researchers have provided theoretical models to address intermittency. Even so, the vast majority of current models, and I would dare to say the dogma in most of the current motor neuroscience literature involves continuous control. In this paper, I focus on an area in which intermittent control has not yet been thoroughly considered, the structure of muscle synergies. A synergy in the muscle space is a group of muscles activated together by a single neural command. Under the assumption that the motor control is intermittent, I present the minimum transition hypothesis and its predictions with regards to the structure of muscle synergies. The minimum transitions hypothesis (MTH asserts that the purpose of synergies is to minimize the effort of the higher level in the hierarchy by minimizing the number of transitions in an intermittent control signal. The implications of the MTH are not only for the structure of the muscle synergies but also to the intermittent and hierarchical nature of the motor system, with various predictions as to the process of skill learning, and important implications to the design of brain machine interfaces and human robot interaction.

  8. Hypothesis to Explain the Size Effect Observed in APO-BMI Compression Tests

    Energy Technology Data Exchange (ETDEWEB)

    Schembri, Philip Edward [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Siranosian, Antranik Antonio [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kingston, Lance Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-01-07

    In 2013 compression tests were performed on cylindrical specimens of carbon-microballoon-APOBMI syntactic foam machined to different lengths (0.25, 0.5, and 2.8 inches1) (Kingston, 2013). In 2014 similar tests were performed on glass-microballoon-APO-BMI of different lengths (~0.15”, ~0.32”, and ~0.57”). In all these tests it was observed that, when strains were calculated from the platen displacement (corrected for machine compliance), the apparent Young’s modulus of the material decreased with specimen size, as shown in Table 1. The reason for this size effect was speculated to be a layer of damage on or near the top and bottom machined surfaces of the specimens (Kingston, Schembri, & Siranosian, 2014). This report examines that hypothesis in further detail.

  9. Ideas and perspectives: hydrothermally driven redistribution and sequestration of early Archaean biomass - the "hydrothermal pump hypothesis"

    Science.gov (United States)

    Duda, Jan-Peter; Thiel, Volker; Bauersachs, Thorsten; Mißbach, Helge; Reinhardt, Manuel; Schäfer, Nadine; Van Kranendonk, Martin J.; Reitner, Joachim

    2018-03-01

    Archaean hydrothermal chert veins commonly contain abundant organic carbon of uncertain origin (abiotic vs. biotic). In this study, we analysed kerogen contained in a hydrothermal chert vein from the ca. 3.5 Ga Dresser Formation (Pilbara Craton, Western Australia). Catalytic hydropyrolysis (HyPy) of this kerogen yielded n-alkanes up to n-C22, with a sharp decrease in abundance beyond n-C18. This distribution ( ≤ n-C18) is very similar to that observed in HyPy products of recent bacterial biomass, which was used as reference material, whereas it differs markedly from the unimodal distribution of abiotic compounds experimentally formed via Fischer-Tropsch-type synthesis. We therefore propose that the organic matter in the Archaean chert veins has a primarily microbial origin. The microbially derived organic matter accumulated in anoxic aquatic (surface and/or subsurface) environments and was then assimilated, redistributed and sequestered by the hydrothermal fluids (hydrothermal pump hypothesis).

  10. The sequential megafaunal collapse hypothesis: Testing with existing data

    Science.gov (United States)

    DeMaster, Douglas P.; Trites, Andrew W.; Clapham, Phillip; Mizroch, Sally; Wade, Paul; Small, Robert J.; Hoef, Jay Ver

    2006-02-01

    Springer et al. [Springer, A.M., Estes, J.A., van Vliet, G.B., Williams, T.M., Doak, D.F., Danner, E.M., Forney, K.A., Pfister, B., 2003. Sequential megafaunal collapse in the North Pacific Ocean: an ongoing legacy of industrial whaling? Proceedings of the National Academy of Sciences 100 (21), 12,223-12,228] hypothesized that great whales were an important prey resource for killer whales, and that the removal of fin and sperm whales by commercial whaling in the region of the Bering Sea/Aleutian Islands (BSAI) in the late 1960s and 1970s led to cascading trophic interactions that caused the sequential decline of populations of harbor seal, northern fur seal, Steller sea lion and northern sea otter. This hypothesis, referred to as the Sequential Megafaunal Collapse (SMC), has stirred considerable interest because of its implication for ecosystem-based management. The SMC has the following assumptions: (1) fin whales and sperm whales were important as prey species in the Bering Sea; (2) the biomass of all large whale species (i.e., North Pacific right, fin, humpback, gray, sperm, minke and bowhead whales) was in decline in the Bering Sea in the 1960s and early 1970s; and (3) pinniped declines in the 1970s and 1980s were sequential. We concluded that the available data are not consistent with the first two assumptions of the SMC. Statistical tests of the timing of the declines do not support the assumption that pinniped declines were sequential. We propose two alternative hypotheses for the declines that are more consistent with the available data. While it is plausible, from energetic arguments, for predation by killer whales to have been an important factor in the declines of one or more of the three populations of pinnipeds and the sea otter population in the BSAI region over the last 30 years, we hypothesize that the declines in pinniped populations in the BSAI can best be understood by invoking a multiple factor hypothesis that includes both bottom-up forcing (as

  11. The Psychoanalytic Concept of Jouissance and the Kindling Hypothesis

    Directory of Open Access Journals (Sweden)

    Yorgos Dimitriadis

    2017-09-01

    Full Text Available This article aims to define the conceptual field of jouissance in Lacanian theory, and put forth the hypothesis of a relationship between certain neurophysiological mechanisms and specific clinical phenomena where jouissance is “kindled” and outside the control of the symbolic process. First, the author briefly introduces Lacan's notion of jouissance and the way it draws on Freud's theorization, and describes the preliminary stages of this conceptual field in Lacan's work. Then, the jouissance related to two other concepts: repetition, with its Freudian and Lacanian nuances, as well as the—exclusively—Lacanian concept of the object petit a. Lacan's later conceptualization of language as jouissance (the notion of lalangue is then discussed in relation to Freud's early ideas (“Letter 52” on the different kinds of inscriptions that help form the mental apparatus. Finally, the author tries to formulate a hypothesis regarding specific neurophysiological mechanisms, based on clinical situations where jouissance becomes “kindled” and escapes the control of the symbolic processes through the neurophysiological mechanisms of conditioning, “kindling-sensitization” and “excitotoxicity.” In these cases, jouissance can have a destructive effect on the body and can affect, among others organs, the brain—a process the author has previously described heuristically as the “psychosomatic diseases of the brain.” This would be a special mechanism of automatism that would be triggered under the specific conditions of the fragility of the signifying chain (foreclosure of the Name-of-the-Father or solidification of the signifying chain in combination with biological factors, including genetic factors. In this process, signifiers are reduced to signals, which in turn may be reduced to stimuli, with a tendency toward self-perpetuation, while affects are reduced to emotions and moods. Thus, conditioning and kindling-sensitization could also

  12. The sequential hypothesis of the function of sleep.

    Science.gov (United States)

    Giuditta, A; Ambrosini, M V; Montagnese, P; Mandile, P; Cotugno, M; Grassi Zucconi, G; Vescia, S

    1995-01-01

    In addition to modulatory roles concerning bodily functions, sleep is assumed to play a main processing role with regard to newly acquired neural information. Elaboration of memory traces acquired during the waking period is assumed to require two sequential steps taking place during slow wave sleep (SWS) and eventually during paradoxical sleep (PS). This view is suggested by several considerations, not the least of which concerns the natural sequence of appearance of SWS and PS in the adult animal. While the involvement of PS in memory processing is well documented, the involvement of SWS is supported by the results of baseline and post-trial EEG analyses carried out in rats trained for a two-way active avoidance task or a spatial habituation task. Together with control analyses, these data indicate that the marked increase in the average duration of post-trial SWS episodes does not reflect the outcome of non-specific contingent factors, such as sleep loss or stress, but is related to memory processing events. Several considerations have furthermore led to the proposal that, during SWS, after a preliminary selection step, the first processing operation consists in the weakening of non-adaptative memory traces. The remaining memory traces would then be stored again under a better configuration during the ensuing PS episode. This view is in agreement with several relevant features of sleep, including the EEG waveforms prevailing during SWS and PS, as well as the ontogenetic sequence of appearance of SWS and PS. Some theoretical considerations on the role of sleep are also in agreement with the sequential hypothesis. More recent data indicate that the learning capacity of rats is correlated with several baseline EEG features of sleep and wakefulness. They include the average duration of PS episodes and of SWS episodes followed by wakefulness (longer in fast learning rats), and the waking EEG power spectrum of fast learning rats whose output is more balanced in the

  13. Problems with the Younger Dryas Boundary (YDB) Impact Hypothesis

    Science.gov (United States)

    Boslough, M.

    2009-12-01

    One breakthrough of 20th-century Earth science was the recognition of impacts as an important geologic process. The most obvious result is a crater. There are more than 170 confirmed terrestrial impact structures with a non-uniform spatial distribution suggesting more to be found. Many have been erased by tectonics and erosion. Deep water impacts do not form craters, and craters in ice sheets disappear when the ice melts. There is growing speculation that such hidden impacts have caused frequent major environmental events of the Holocene, but this is inconsistent with the astronomically-constrained population of Earth-crossing asteroids. Impacts can have consequences much more significant than excavation of a crater. The K/T boundary mass extinction is attributed to the environmental effects of a major impact, and some researchers argue that other extinctions, abrupt climate changes, and even civilization collapses have resulted from impacts. Nuclear winter models suggest that 2-km diameter asteroids exceed a "global catastrophe threshold" by injecting sufficient dust into the stratosphere to cause short-term climate changes, but would not necessarily collapse most natural ecosystems or cause mass extinctions. Globally-catastrophic impacts recur on timescales of about one million years. The 1994 collision of Comet Shoemaker-Levy 9 with Jupiter led us recognize the significance of terrestrial airbursts caused by objects exploding violently in Earth’s atmosphere. We have invoked airbursts to explain rare forms of non-volcanic glasses and melts by using high-resolution computational models to improve our understanding of atmospheric explosions, and have suggested that multiple airbursts from fragmented impactors could be responsible for regional effects. Our models have been cited in support of the widely-publicized YDB impact hypothesis. Proponents claim that a broken comet exploded over North America, with some fragments cratering the Laurentide Ice Sheet. They

  14. Introducing the refined gravity hypothesis of extreme sexual size dimorphism

    Directory of Open Access Journals (Sweden)

    Corcobado Guadalupe

    2010-08-01

    Full Text Available Abstract Background Explanations for the evolution of female-biased, extreme Sexual Size Dimorphism (SSD, which has puzzled researchers since Darwin, are still controversial. Here we propose an extension of the Gravity Hypothesis (i.e., the GH, which postulates a climbing advantage for small males that in conjunction with the fecundity hypothesis appears to have the most general power to explain the evolution of SSD in spiders so far. In this "Bridging GH" we propose that bridging locomotion (i.e., walking upside-down under own-made silk bridges may be behind the evolution of extreme SSD. A biomechanical model shows that there is a physical constraint for large spiders to bridge. This should lead to a trade-off between other traits and dispersal in which bridging would favor smaller sizes and other selective forces (e.g. fecundity selection in females would favor larger sizes. If bridging allows faster dispersal, small males would have a selective advantage by enjoying more mating opportunities. We predicted that both large males and females would show a lower propensity to bridge, and that SSD would be negatively correlated with sexual dimorphism in bridging propensity. To test these hypotheses we experimentally induced bridging in males and females of 13 species of spiders belonging to the two clades in which bridging locomotion has evolved independently and in which most of the cases of extreme SSD in spiders are found. Results We found that 1 as the degree of SSD increased and females became larger, females tended to bridge less relative to males, and that 2 smaller males and females show a higher propensity to bridge. Conclusions Physical constraints make bridging inefficient for large spiders. Thus, in species where bridging is a very common mode of locomotion, small males, by being more efficient at bridging, will be competitively superior and enjoy more mating opportunities. This "Bridging GH" helps to solve the controversial question of

  15. Introducing the refined gravity hypothesis of extreme sexual size dimorphism.

    Science.gov (United States)

    Corcobado, Guadalupe; Rodríguez-Gironés, Miguel A; De Mas, Eva; Moya-Laraño, Jordi

    2010-08-03

    Explanations for the evolution of female-biased, extreme Sexual Size Dimorphism (SSD), which has puzzled researchers since Darwin, are still controversial. Here we propose an extension of the Gravity Hypothesis (i.e., the GH, which postulates a climbing advantage for small males) that in conjunction with the fecundity hypothesis appears to have the most general power to explain the evolution of SSD in spiders so far. In this "Bridging GH" we propose that bridging locomotion (i.e., walking upside-down under own-made silk bridges) may be behind the evolution of extreme SSD. A biomechanical model shows that there is a physical constraint for large spiders to bridge. This should lead to a trade-off between other traits and dispersal in which bridging would favor smaller sizes and other selective forces (e.g. fecundity selection in females) would favor larger sizes. If bridging allows faster dispersal, small males would have a selective advantage by enjoying more mating opportunities. We predicted that both large males and females would show a lower propensity to bridge, and that SSD would be negatively correlated with sexual dimorphism in bridging propensity. To test these hypotheses we experimentally induced bridging in males and females of 13 species of spiders belonging to the two clades in which bridging locomotion has evolved independently and in which most of the cases of extreme SSD in spiders are found. We found that 1) as the degree of SSD increased and females became larger, females tended to bridge less relative to males, and that 2) smaller males and females show a higher propensity to bridge. Physical constraints make bridging inefficient for large spiders. Thus, in species where bridging is a very common mode of locomotion, small males, by being more efficient at bridging, will be competitively superior and enjoy more mating opportunities. This "Bridging GH" helps to solve the controversial question of what keeps males small and also contributes to

  16. The Psychoanalytic Concept of Jouissance and the Kindling Hypothesis.

    Science.gov (United States)

    Dimitriadis, Yorgos

    2017-01-01

    This article aims to define the conceptual field of jouissance in Lacanian theory, and put forth the hypothesis of a relationship between certain neurophysiological mechanisms and specific clinical phenomena where jouissance is "kindled" and outside the control of the symbolic process. First, the author briefly introduces Lacan's notion of jouissance and the way it draws on Freud's theorization, and describes the preliminary stages of this conceptual field in Lacan's work. Then, the jouissance related to two other concepts: repetition, with its Freudian and Lacanian nuances, as well as the-exclusively-Lacanian concept of the object petit a . Lacan's later conceptualization of language as jouissance (the notion of lalangue ) is then discussed in relation to Freud's early ideas ("Letter 52") on the different kinds of inscriptions that help form the mental apparatus. Finally, the author tries to formulate a hypothesis regarding specific neurophysiological mechanisms, based on clinical situations where jouissance becomes "kindled" and escapes the control of the symbolic processes through the neurophysiological mechanisms of conditioning, "kindling-sensitization" and "excitotoxicity." In these cases, jouissance can have a destructive effect on the body and can affect, among others organs, the brain-a process the author has previously described heuristically as the "psychosomatic diseases of the brain." This would be a special mechanism of automatism that would be triggered under the specific conditions of the fragility of the signifying chain (foreclosure of the Name-of-the-Father or solidification of the signifying chain) in combination with biological factors, including genetic factors. In this process, signifiers are reduced to signals, which in turn may be reduced to stimuli, with a tendency toward self-perpetuation, while affects are reduced to emotions and moods. Thus, conditioning and kindling-sensitization could also be understood in terms of a "semiotic

  17. The Psychoanalytic Concept of Jouissance and the Kindling Hypothesis

    Science.gov (United States)

    Dimitriadis, Yorgos

    2017-01-01

    This article aims to define the conceptual field of jouissance in Lacanian theory, and put forth the hypothesis of a relationship between certain neurophysiological mechanisms and specific clinical phenomena where jouissance is “kindled” and outside the control of the symbolic process. First, the author briefly introduces Lacan's notion of jouissance and the way it draws on Freud's theorization, and describes the preliminary stages of this conceptual field in Lacan's work. Then, the jouissance related to two other concepts: repetition, with its Freudian and Lacanian nuances, as well as the—exclusively—Lacanian concept of the object petit a. Lacan's later conceptualization of language as jouissance (the notion of lalangue) is then discussed in relation to Freud's early ideas (“Letter 52”) on the different kinds of inscriptions that help form the mental apparatus. Finally, the author tries to formulate a hypothesis regarding specific neurophysiological mechanisms, based on clinical situations where jouissance becomes “kindled” and escapes the control of the symbolic processes through the neurophysiological mechanisms of conditioning, “kindling-sensitization” and “excitotoxicity.” In these cases, jouissance can have a destructive effect on the body and can affect, among others organs, the brain—a process the author has previously described heuristically as the “psychosomatic diseases of the brain.” This would be a special mechanism of automatism that would be triggered under the specific conditions of the fragility of the signifying chain (foreclosure of the Name-of-the-Father or solidification of the signifying chain) in combination with biological factors, including genetic factors. In this process, signifiers are reduced to signals, which in turn may be reduced to stimuli, with a tendency toward self-perpetuation, while affects are reduced to emotions and moods. Thus, conditioning and kindling-sensitization could also be understood in

  18. Dehydration Influences Mood and Cognition: A Plausible Hypothesis?

    Directory of Open Access Journals (Sweden)

    David Benton

    2011-05-01

    Full Text Available The hypothesis was considered that a low fluid intake disrupts cognition and mood. Most research has been carried out on young fit adults, who typically have exercised, often in heat. The results of these studies are inconsistent, preventing any conclusion. Even if the findings had been consistent, confounding variables such as fatigue and increased temperature make it unwise to extrapolate these findings. Thus in young adults there is little evidence that under normal living conditions dehydration disrupts cognition, although this may simply reflect a lack of relevant evidence. There remains the possibility that particular populations are at high risk of dehydration. It is known that renal function declines in many older individuals and thirst mechanisms become less effective. Although there are a few reports that more dehydrated older adults perform cognitive tasks less well, the body of information is limited and there have been little attempt to improve functioning by increasing hydration status. Although children are another potentially vulnerable group that have also been subject to little study, they are the group that has produced the only consistent findings in this area. Four intervention studies have found improved performance in children aged 7 to 9 years. In these studies children, eating and drinking as normal, have been tested on occasions when they have and not have consumed a drink. After a drink both memory and attention have been found to be improved.

  19. Medical hypothesis: Xenoestrogens as preventable causes of breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Davis, D.L. (Department of Health and Human Services, Washington, DC (United States)); Bradlow, H.L. (Cornell Univ., Ithaca, NY (United States)); Wolff, M. (City Univ. of New York, NY (United States)); Woodruff, T. (Univ. of California, San Francisco, CA (United States)); Hoel, D.G. (Medical Univ. of South Carolina, SC (United States)); Anton-Culver, H. (Univ. of California, Irvine, CA (United States))

    1993-10-01

    Changes in documented risk factors for breast cancer and rates of screening cannot completely explain recent increases in incidence or mortality. Established risk factors for breast cancer, including genetics, account for at best 30% of cases. Most of these risk factors can be linked to total lifetime exposure to bioavailable estrogens. Experimental evidence reveals that compounds such as some chlorinated organics, polycyclic aromatic hydrocarbons (PAHs), triazine herbicides, and pharmaceuticals affect estrogen production and metabolism and thus function as xenoestrogens. Many of these xenoestrogenic compounds also experimentally induce mammary carcinogensis. Recent epidemiologic studies have found that breast fat and serum lipids of women with breast cancer contain significantly elevated levels of some chlorinated organics compared with noncancer controls. As the proportion of inherited breast cancer in the population is small, most breast cancers are due to acquired mutations. The authors hypothesize that substances such as xenoestrogens increase the risk of breast cancer by mechanisms which include interaction with breast-cancer susceptibility genes. A series of epidemiologic studies need to be developed to evaluate this hypothesis.

  20. Can We Determine High Risk Groups in Schizophrenia? A Hypothesis

    Directory of Open Access Journals (Sweden)

    Bulent Demirbek

    2012-09-01

    Full Text Available Neurodevelopmental hypothesis suggested that schizophrenia is a disorder of early brain development, in which the brain structural abnormalities are present. The causes of the abnormal processes remains unclear however, Genetics vulnerability, obstetric complications and viral infections have been shown to play a role in this disorder. Several studies have shown a greater incidence of winter or spring births in patients. Prenatal and perinatal infections, especially in the second trimester of pregnancy, have been considered a plausible risk factor for schizophrenia. Maternal exposure to influenza, herpes viruses, varicella zoster virus, Epstein-Barr virus, cytomegalovirus and rarely rubella virus infections confers an increased risk of schizophrenia to the developing offspring. As clinicians, we observed that our patients with psychotic disorder were not exposed to the viral infections even during epidemic. We hypothesized that perinatal viral infections have been associated with lifelong immunity to this infectious diseases which on the other hand cause an increased risk of developing schizophrenia. If we could determine antibodies against these viruses among patients with schizophrenia, perhaps we will be able to identify accurate markers heralding psychotic illness as well as can use these markers in a large population-based sample.

  1. Subsystem eigenstate thermalization hypothesis for entanglement entropy in CFT

    Science.gov (United States)

    He, Song; Lin, Feng-Li; Zhang, Jia-ju

    2017-08-01

    We investigate a weak version of subsystem eigenstate thermalization hypothesis (ETH) for a two-dimensional large central charge conformal field theory by comparing the local equivalence of high energy state and thermal state of canonical ensemble. We evaluate the single-interval Rényi entropy and entanglement entropy for a heavy primary state in short interval expansion. We verify the results of Rényi entropy by two different replica methods. We find nontrivial results at the eighth order of short interval expansion, which include an infinite number of higher order terms in the large central charge expansion. We then evaluate the relative entropy of the reduced density matrices to measure the difference between the heavy primary state and thermal state of canonical ensemble, and find that the aforementioned nontrivial eighth order results make the relative entropy unsuppressed in the large central charge limit. By using Pinsker's and Fannes-Audenaert inequalities, we can exploit the results of relative entropy to yield the lower and upper bounds on trace distance of the excited-state and thermal-state reduced density matrices. Our results are consistent with subsystem weak ETH, which requires the above trace distance is of power-law suppression by the large central charge. However, we are unable to pin down the exponent of power-law suppression. As a byproduct we also calculate the relative entropy to measure the difference between the reduced density matrices of two different heavy primary states.

  2. The fetal programming of telomere biology hypothesis: an update

    Science.gov (United States)

    Entringer, Sonja; Buss, Claudia; Wadhwa, Pathik D.

    2018-01-01

    Research on mechanisms underlying fetal programming of health and disease risk has focused primarily on processes that are specific to cell types, organs or phenotypes of interest. However, the observation that developmental conditions concomitantly influence a diverse set of phenotypes, the majority of which are implicated in age-related disorders, raises the possibility that such developmental conditions may additionally exert effects via a common underlying mechanism that involves cellular/molecular ageing–related processes. In this context, we submit that telomere biology represents a process of particular interest in humans because, firstly, this system represents among the most salient antecedent cellular phenotypes for common age-related disorders; secondly, its initial (newborn) setting appears to be particularly important for its long-term effects; and thirdly, its initial setting appears to be plastic and under developmental regulation. We propose that the effects of suboptimal intrauterine conditions on the initial setting of telomere length and telomerase expression/activity capacity may be mediated by the programming actions of stress-related maternal–placental–fetal oxidative, immune, endocrine and metabolic pathways in a manner that may ultimately accelerate cellular dysfunction, ageing and disease susceptibility over the lifespan. This perspectives paper provides an overview of each of the elements underlying this hypothesis, with an emphasis on recent developments, findings and future directions. This article is part of the theme issue ‘Understanding diversity in telomere dynamics’. PMID:29335381

  3. Convergent evolution of germ granule nucleators: A hypothesis.

    Science.gov (United States)

    Kulkarni, Arpita; Extavour, Cassandra G

    2017-10-01

    Germ cells have been considered "the ultimate stem cell" because they alone, during normal development of sexually reproducing organisms, are able to give rise to all organismal cell types. Morphological descriptions of a specialized cytoplasm termed 'germ plasm' and associated electron dense ribonucleoprotein (RNP) structures called 'germ granules' within germ cells date back as early as the 1800s. Both germ plasm and germ granules are implicated in germ line specification across metazoans. However, at a molecular level, little is currently understood about the molecular mechanisms that assemble these entities in germ cells. The discovery that in some animals, the gene products of a small number of lineage-specific genes initiate the assembly (also termed nucleation) of germ granules and/or germ plasm is the first step towards facilitating a better understanding of these complex biological processes. Here, we draw on research spanning over 100years that supports the hypothesis that these nucleator genes may have evolved convergently, allowing them to perform analogous roles across animal lineages. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  4. Multitarget botanical pharmacotherapy in major depression: a toxic brain hypothesis.

    Science.gov (United States)

    Tang, Siu W; Tang, Wayne H; Leonard, Brain E

    2017-11-01

    A significant number of patients with major depression do not respond optimally to current antidepressant drugs. As depression is likely to be a heterogeneous disorder, it is possible that existing neurotransmitter-based antidepressant drugs do not fully address other pathologies that may exist in certain cases. Biological pathologies related to depression that have been proposed and studied extensively include inflammation and immunology, hypercortisolemia, oxidative stress, and impaired angiogenesis. Such pathologies may induce neurodegeneration, which in turn causes cognitive impairment, a symptom increasingly being recognized in depression. A neurotoxic brain hypothesis unifying all these factors may explain the heterogeneity of depression as well as cognitive decline and antidepressant drug resistance in some patients. Compared with neurotransmitter-based antidepressant drugs, many botanical compounds in traditional medicine used for the treatment of depression and its related symptoms have been discovered to be anti-inflammatory, immunoregulatory, anti-infection, antioxidative, and proangiogenic. Some botanical compounds also exert actions on neurotransmission. This multitarget nature of botanical medicine may act through the amelioration of the neurotoxic brain environment in some patients resistant to neurotransmitter-based antidepressant drugs. A multitarget multidimensional approach may be a reasonable solution for patients resistant to neurotransmitter-based antidepressant drugs.

  5. An exploration of the social brain hypothesis in insects

    Directory of Open Access Journals (Sweden)

    Mathieu eLihoreau

    2012-11-01

    Full Text Available The ‘social brain hypothesis’ posits that the cognitive demands of sociality have driven the evolution of substantially enlarged brains in primates and some other mammals. Whether such reasoning can apply to all social animals is an open question. Here we examine the evolutionary relationships between sociality, cognition and brain size in insects, a taxonomic group characterized by an extreme sophistication of social behaviors and relatively simple nervous systems. We discuss the application of the social brain hypothesis in this group based on comparative studies of brain volumes across species exhibiting various levels of social complexity. We illustrate how some of the major behavioral innovations of social insects may in fact require little information processing and minor adjustments of neural circuitry, thus potentially selecting for more specialized rather than bigger brains. We argue that future work aiming to understand how animal behavior, cognition and brains are shaped by the environment (including social interactions should focus on brain functions and identify neural correlates of social tasks, not only brain sizes.

  6. Martingales, detrending data, and the efficient market hypothesis

    Science.gov (United States)

    McCauley, Joseph L.; Bassler, Kevin E.; Gunaratne, Gemunu H.

    2008-01-01

    We discuss martingales, detrending data, and the efficient market hypothesis (EMH) for stochastic processes x( t) with arbitrary diffusion coefficients D( x, t). Beginning with x-independent drift coefficients R( t) we show that martingale stochastic processes generate uncorrelated, generally non-stationary increments. Generally, a test for a martingale is therefore a test for uncorrelated increments. A detrended process with an x-dependent drift coefficient is generally not a martingale, and so we extend our analysis to include the class of ( x, t)-dependent drift coefficients of interest in finance. We explain why martingales look Markovian at the level of both simple averages and 2-point correlations. And while a Markovian market has no memory to exploit and presumably cannot be beaten systematically, it has never been shown that martingale memory cannot be exploited in 3-point or higher correlations to beat the market. We generalize our Markov scaling solutions presented earlier, and also generalize the martingale formulation of the EMH to include ( x, t)-dependent drift in log returns. We also use the analysis of this paper to correct a misstatement of the ‘fair game’ condition in terms of serial correlations in Fama's paper on the EMH. We end with a discussion of Levy's characterization of Brownian motion and prove that an arbitrary martingale is topologically inequivalent to a Wiener process.

  7. Biodiversity, productivity, and the spatial insurance hypothesis revisited

    Science.gov (United States)

    Shanafelt, David W.; Dieckmann, Ulf; Jonas, Matthias; Franklin, Oskar; Loreau, Michel; Perrings, Charles

    2015-01-01

    Accelerating rates of biodiversity loss have led ecologists to explore the effects of species richness on ecosystem functioning and the flow of ecosystem services. One explanation of the relationship between biodiversity and ecosystem functioning lies in the spatial insurance hypothesis, which centers on the idea that productivity and stability increase with biodiversity in a temporally varying, spatially heterogeneous environment. However, there has been little work on the impact of dispersal where environmental risks are more or less spatially correlated, or where dispersal rates are variable. In this paper, we extend the original Loreau model to consider stochastic temporal variation in resource availability, which we refer to as “environmental risk,” and heterogeneity in species dispersal rates. We find that asynchronies across communities and species provide community-level stabilizing effects on productivity, despite varying levels of species richness. Although intermediate dispersal rates play a role in mitigating risk, they are less effective in insuring productivity against global (metacommunity-level) than local (individual community-level) risks. These results are particularly interesting given the emergence of global sources of risk such as climate change or the closer integration of world markets. Our results offer deeper insights into the Loreau model and new perspectives on the effectiveness of spatial insurance in the face of environmental risks. PMID:26100182

  8. Earthquake hoax in Ghana: exploration of the Cry Wolf hypothesis

    Directory of Open Access Journals (Sweden)

    Ishmael D. Norman

    2012-04-01

    Full Text Available This paper investigated the belief of the news of impending earthquake from any source in the context of the Cry Wolf hypothesis as well as the belief of the news of any other imminent disaster from any source. We were also interested in the correlation between preparedness, risk perception and antecedents. This explorative study consisted of interviews, literature and Internet reviews. Sampling was of a simple random nature. Stratification was carried out by sex and residence type. The sample size of (N=400, consisted of 195 males and 205 Females. Further stratification was based on residential classification used by the municipalities. The study revealed that a person would believe news of an impending earthquake from any source, (64.4% and a model significance of (P=0.000. It also showed that a person would believe news of any other impending disaster from any source, (73.1% and a significance of (P=0.003. There is association between background, risk perception and preparedness. Emergency preparedness is weak. Earthquake awareness needs to be re-enforced. There is a critical need for public education of earthquake preparedness. The authors recommend developing emergency response program for earthquakes, standard operating procedures for a national risk communication through all media including instant bulk messaging.

  9. Behavioral Variability and Somatic Mosaicism: A Cytogenomic Hypothesis.

    Science.gov (United States)

    Vorsanova, Svetlana G; Zelenova, Maria A; Yurov, Yuri B; Iourov, Ivan Y

    2018-04-01

    Behavioral sciences are inseparably related to genetics. A variety of neurobehavioral phenotypes are suggested to result from genomic variations. However, the contribution of genetic factors to common behavioral disorders (i.e. autism, schizophrenia, intellectual disability) remains to be understood when an attempt to link behavioral variability to a specific genomic change is made. Probably, the least appreciated genetic mechanism of debilitating neurobehavioral disorders is somatic mosaicism or the occurrence of genetically diverse (neuronal) cells in an individual's brain. Somatic mosaicism is assumed to affect directly the brain being associated with specific behavioral patterns. As shown in studies of chromosome abnormalities (syndromes), genetic mosaicism is able to change dynamically the phenotype due to inconsistency of abnormal cell proportions. Here, we hypothesize that brain-specific postzygotic changes of mosaicism levels are able to modulate variability of behavioral phenotypes. More precisely, behavioral phenotype variability in individuals exhibiting somatic mosaicism might correlate with changes in the amount of genetically abnormal cells throughout the lifespan. If proven, the hypothesis can be used as a basis for therapeutic interventions through regulating levels of somatic mosaicism to increase functioning and to improve overall condition of individuals with behavioral problems.

  10. Tertiary ice sheet dynamics: The Snow Gun Hypothesis

    Science.gov (United States)

    Prentice, M. L.; Matthews, R. K.

    1991-04-01

    We observe strong negative correlation between Tertiary low- to mid-latitude planktonic foraminiferal δ18O and the difference between these data and coeval benthic foraminiferal δ18O. Late Quaternary data do not show this correlation. Coupling statistical model/δ18O comparisons and evidence for Antarctic ice and ocean temperature variation, we infer that Tertiary ice volume, recorded by tropical planktonic δ18O, increased as the deep ocean warmed. Because the isotopic signatures of deepwater temperature variation and ice volume change were of opposite sign, the sum of these signals in Tertiary benthic δ18O became lost in the noise. This renders low correlation between Tertiary planktonic and benthic δ18O time series compared to late Quaternary data. We contend that Tertiary ice sheet growth was commonly driven by warming of deep water from low- to mid-latitude marginal seas (snow gun hypothesis). In contrast, late Quaternary ice sheets grew as deep water, formed at high latitude, cooled. Because tectonic forcing and orbital forcing at low-latitude primarily controlled production and temperature variations of this Warm Saline Deep Water, these influences largely dictated Tertiary ice volume fluctuations. Through the Tertiary, we infer ice volume fluctuations to be an important component of sea level history on timescales between 103 and 107 years.

  11. An epigenetic hypothesis for the genomic memory of pain.

    Directory of Open Access Journals (Sweden)

    Sebastian eAlvarado

    2015-03-01

    Full Text Available Chronic pain is accompanied with long-term sensory, affective and cognitive disturbances. What are the mechanisms that mediate the long-term consequences of painful experiences and embed them in the genome? We hypothesize that alterations in DNA methylation, an enzymatic covalent modification of cytosine bases in DNA, serve as a genomic memory of pain in the adult cortex. DNA methylation is an epigenetic mechanism for long-term regulation of gene expression. Neuronal plasticity at the neuroanatomical, functional, morphological, physiological and molecular levels has been demonstrated throughout the neuroaxis in response to persistent pain, including in the adult prefrontal cortex (PFC. We have previously reported widespread changes in gene expression and DNA methylation in the PFC many months following peripheral nerve injury. In support of this hypothesis, we show here that up-regulation of a gene involved with synaptic function, Synaptotagmin II (syt2, in the PFC in a chronic pain model is associated with long-term changes in DNA methylation. The challenges of understanding the contributions of epigenetic mechanisms such as DNA methylation within the PFC to pain chronicity and their therapeutic implications are discussed.

  12. OPEC and Venezuelan oil production: Evidence against a cartel hypothesis

    International Nuclear Information System (INIS)

    Reynolds, Douglas B.; Pippenger, Michael K.

    2010-01-01

    This study revisits the OPEC cartel hypothesis using a case study. A test is conducted to see if Venezuela has its production Granger cause its OPEC quota or whether the OPEC quota for Venezuela Granger causes Venezuelan production. The results show both occur at different times. In the short run, OPEC's oil production quota for Venezuela Granger causes Venezuelan production. However, shortly after cuts, Venezuela cheats on agreements, suggesting a tit-for-tat oligopoly game, which is not anti-competitive. In the long run, we show that Venezuelan oil production Granger causes OPEC's quota for Venezuela, but not vice versa. Having Venezuelan oil production Granger cause OPEC quotas for Venezuela in the long run suggests OPEC does not coordinate outputs as much as it reacts to them. The evidence suggests Venezuela is not a part of an OPEC anti-competitive syndicate even though we show that Venezuelan oil production is low. An alternative explanation for why Venezuela and possibly other OPEC members have low oil production outputs is that institutions and risk aversion, not cartel participation, is the cause. A vector error correction model shows that there is no tendency for Venezuelan oil production to converge to OPEC's quota for Venezuela.

  13. The Smoothing Hypothesis, Stock Returns and Risk in Brazil

    Directory of Open Access Journals (Sweden)

    Antonio Lopo Martinez

    2011-01-01

    Full Text Available Income smoothing is defined as the deliberate normalization of income in order to reach a desired trend. If the smoothing causes more information to be reflected in the stock price, it is likely to improve the allocation of resources and can be a critical factor in investment decisions. This study aims to build metrics to determine the degree of smoothing in Brazilian public companies, to classify them as smoothing and non-smoothing companies and additionally to present evidence on the long-term relationship between the smoothing hypothesis and stock return and risk. Using the Economatica and CVM databases, this study focuses on 145 companies in the period 1998-2007. We find that Brazilian smoothers have a smaller degree of systemic risk than non-smoothers. In average terms, the beta of smoothers is significantly lower than non-smoothers. Regarding return, we find that the abnormal annualized returns of smoothers are significantly higher. We confirm differences in the groups by nonparametric and parametric tests in cross section or as time series, indicating that there is a statistically significant difference in performance in the Brazilian market between firms that do and do not engage in smoothing.

  14. An Integrated Hypothesis on the Domestication of Bactris gasipaes.

    Science.gov (United States)

    Galluzzi, Gea; Dufour, Dominique; Thomas, Evert; van Zonneveld, Maarten; Escobar Salamanca, Andrés Felipe; Giraldo Toro, Andrés; Rivera, Andrés; Salazar Duque, Hector; Suárez Baron, Harold; Gallego, Gerardo; Scheldeman, Xavier; Gonzalez Mejia, Alonso

    2015-01-01

    Peach palm (Bactris gasipaes Kunth) has had a central place in the livelihoods of people in the Americas since pre-Columbian times, notably for its edible fruits and multi-purpose wood. The botanical taxon includes both domesticated and wild varieties. Domesticated var gasipaes is believed to derive from one or more of the three wild types of var. chichagui identified today, although the exact dynamics and location of the domestication are still uncertain. Drawing on a combination of molecular and phenotypic diversity data, modeling of past climate suitability and existing literature, we present an integrated hypothesis about peach palm's domestication. We support a single initial domestication event in south western Amazonia, giving rise to var. chichagui type 3, the putative incipient domesticate. We argue that subsequent dispersal by humans across western Amazonia, and possibly into Central America allowed for secondary domestication events through hybridization with resident wild populations, and differential human selection pressures, resulting in the diversity of present-day landraces. The high phenotypic diversity in the Ecuadorian and northern Peruvian Amazon suggest that human selection of different traits was particularly intense there. While acknowledging the need for further data collection, we believe that our results contribute new insights and tools to understand domestication and dispersal patterns of this important native staple, as well as to plan for its conservation.

  15. [The auto-addictive hypothesis of pathological eating disorders].

    Science.gov (United States)

    Lienard, Yasmine; Vamecq, Joseph

    2004-10-23

    The pathogenic role of self-addiction. Addiction to an endogenous chemical is a new paradigm termed 'self-addiction'. It may contribute to the development of certain habits, the pathological nature of which may set-in on the basis of this "self-addictive"dimension. Pathological eating habits could be inscribed in this perspective. Two extreme situations. In well-fed populations, the ingestion of food does not represent a limiting phase in the global feeding process. Its pathological management may, however, lead to two extreme situations: the absence of ingestion (anorexia) and excessive ingestion (bulimia). In favour of the self-addictive hypothesis. Eating disorders are associated with abnormal levels of endorphins and share clinical similarities with psychoactive drug abuse. The key role of endorphins has recently been demonstrated in animals with regard to certain aspects of normal, pathological and experimental eating habits (food restriction combined with stress, locomotor hyperactivity). The factors leading to pathological eating habits. Neurobiological bases for eating disorders and their durability have recently come to light in the recent implication of abnormalities in the recompense system in the onset of addiction. The endorphin self-addictive model in fact appears the most pertinent with regard to the clinical profile of eating habits and integrates the role of stress.

  16. Refuge-effect hypothesis and the demise of the Dodo.

    Science.gov (United States)

    Roberts, David L

    2013-12-01

    The Dodo was last sighted on the inshore island of Ile d'Ambre in 1662, nearly 25 years after the previous sighting on the mainland of Mauritius. It has been suggested that its survival on the inshore island is representative of the refuge effect. Understanding what constitutes significant persistence is fundamental to conservation. I tested the refuge-effect hypothesis for the persistence of the Dodo (Raphus cucullatus) on an inshore island beyond that of the mainland population. For a location to be considered a refuge, most current definitions suggest that both spatial and temporal isolation from the cause of disturbance are required. These results suggest the island was not a refuge for the Dodo because the sighting in 1662 was not temporally isolated from that of the mainland sightings. Furthermore, with only approximately 350 m separating Ile d'Ambre from the mainland of Mauritius, it is unlikely this population of Dodos was spatially isolated. Hipótesis del Efecto Refugio y la Desaparición del Dodo. © 2013 Society for Conservation Biology.

  17. cit: hypothesis testing software for mediation analysis in genomic applications.

    Science.gov (United States)

    Millstein, Joshua; Chen, Gary K; Breton, Carrie V

    2016-08-01

    The challenges of successfully applying causal inference methods include: (i) satisfying underlying assumptions, (ii) limitations in data/models accommodated by the software and (iii) low power of common multiple testing approaches. The causal inference test (CIT) is based on hypothesis testing rather than estimation, allowing the testable assumptions to be evaluated in the determination of statistical significance. A user-friendly software package provides P-values and optionally permutation-based FDR estimates (q-values) for potential mediators. It can handle single and multiple binary and continuous instrumental variables, binary or continuous outcome variables and adjustment covariates. Also, the permutation-based FDR option provides a non-parametric implementation. Simulation studies demonstrate the validity of the cit package and show a substantial advantage of permutation-based FDR over other common multiple testing strategies. The cit open-source R package is freely available from the CRAN website (https://cran.r-project.org/web/packages/cit/index.html) with embedded C ++ code that utilizes the GNU Scientific Library, also freely available (http://www.gnu.org/software/gsl/). joshua.millstein@usc.edu Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  18. Dissimilarities of reduced density matrices and eigenstate thermalization hypothesis

    Science.gov (United States)

    He, Song; Lin, Feng-Li; Zhang, Jia-ju

    2017-12-01

    We calculate various quantities that characterize the dissimilarity of reduced density matrices for a short interval of length ℓ in a two-dimensional (2D) large central charge conformal field theory (CFT). These quantities include the Rényi entropy, entanglement entropy, relative entropy, Jensen-Shannon divergence, as well as the Schatten 2-norm and 4-norm. We adopt the method of operator product expansion of twist operators, and calculate the short interval expansion of these quantities up to order of ℓ9 for the contributions from the vacuum conformal family. The formal forms of these dissimilarity measures and the derived Fisher information metric from contributions of general operators are also given. As an application of the results, we use these dissimilarity measures to compare the excited and thermal states, and examine the eigenstate thermalization hypothesis (ETH) by showing how they behave in high temperature limit. This would help to understand how ETH in 2D CFT can be defined more precisely. We discuss the possibility that all the dissimilarity measures considered here vanish when comparing the reduced density matrices of an excited state and a generalized Gibbs ensemble thermal state. We also discuss ETH for a microcanonical ensemble thermal state in a 2D large central charge CFT, and find that it is approximately satisfied for a small subsystem and violated for a large subsystem.

  19. Fractal supersymmetric QM, Geometric Probability and the Riemann Hypothesis

    CERN Document Server

    Castro, C

    2004-01-01

    The Riemann's hypothesis (RH) states that the nontrivial zeros of the Riemann zeta-function are of the form $ s_n =1/2+i\\lambda_n $. Earlier work on the RH based on supersymmetric QM, whose potential was related to the Gauss-Jacobi theta series, allows to provide the proper framework to construct the well defined algorithm to compute the probability to find a zero (an infinity of zeros) in the critical line. Geometric probability theory furnishes the answer to the very difficult question whether the probability that the RH is true is indeed equal to unity or not. To test the validity of this geometric probabilistic framework to compute the probability if the RH is true, we apply it directly to the the hyperbolic sine function $ \\sinh (s) $ case which obeys a trivial analog of the RH (the HSRH). Its zeros are equally spaced in the imaginary axis $ s_n = 0 + i n \\pi $. The geometric probability to find a zero (and an infinity of zeros) in the imaginary axis is exactly unity. We proceed with a fractal supersymme...

  20. A Blind Test of the Younger Dryas Impact Hypothesis.

    Directory of Open Access Journals (Sweden)

    Vance Holliday

    Full Text Available The Younger Dryas Impact Hypothesis (YDIH states that North America was devastated by some sort of extraterrestrial event ~12,800 calendar years before present. Two fundamental questions persist in the debate over the YDIH: Can the results of analyses for purported impact indicators be reproduced? And are the indicators unique to the lower YD boundary (YDB, i.e., ~12.8k cal yrs BP? A test reported here presents the results of analyses that address these questions. Two different labs analyzed identical splits of samples collected at, above, and below the ~12.8ka zone at the Lubbock Lake archaeological site (LL in northwest Texas. Both labs reported similar variation in levels of magnetic micrograins (>300 mg/kg >12.8ka and <11.5ka, but <150 mg/kg 12.8ka to 11.5ka. Analysis for magnetic microspheres in one split, reported elsewhere, produced very low to nonexistent levels throughout the section. In the other split, reported here, the levels of magnetic microspherules and nanodiamonds are low or nonexistent at, below, and above the YDB with the notable exception of a sample <11,500 cal years old. In that sample the claimed impact proxies were recovered at abundances two to four orders of magnitude above that from the other samples. Reproducibility of at least some analyses are problematic. In particular, no standard criteria exist for identification of magnetic spheres. Moreover, the purported impact proxies are not unique to the YDB.

  1. An Integrated Hypothesis on the Domestication of Bactris gasipaes.

    Directory of Open Access Journals (Sweden)

    Gea Galluzzi

    Full Text Available Peach palm (Bactris gasipaes Kunth has had a central place in the livelihoods of people in the Americas since pre-Columbian times, notably for its edible fruits and multi-purpose wood. The botanical taxon includes both domesticated and wild varieties. Domesticated var gasipaes is believed to derive from one or more of the three wild types of var. chichagui identified today, although the exact dynamics and location of the domestication are still uncertain. Drawing on a combination of molecular and phenotypic diversity data, modeling of past climate suitability and existing literature, we present an integrated hypothesis about peach palm's domestication. We support a single initial domestication event in south western Amazonia, giving rise to var. chichagui type 3, the putative incipient domesticate. We argue that subsequent dispersal by humans across western Amazonia, and possibly into Central America allowed for secondary domestication events through hybridization with resident wild populations, and differential human selection pressures, resulting in the diversity of present-day landraces. The high phenotypic diversity in the Ecuadorian and northern Peruvian Amazon suggest that human selection of different traits was particularly intense there. While acknowledging the need for further data collection, we believe that our results contribute new insights and tools to understand domestication and dispersal patterns of this important native staple, as well as to plan for its conservation.

  2. The intense world syndrome - an alternative hypothesis for autism

    Directory of Open Access Journals (Sweden)

    Henry Markram

    2007-10-01

    Full Text Available Autism is a devastating neurodevelopmental disorder with a polygenetic predisposition that seems to be triggered by multiple environmental factors during embryonic and/or early postnatal life. While significant advances have been made in identifying the neuronal structures and cells affected, a unifying theory that could explain the manifold autistic symptoms has still not emerged. Based on recent synaptic, cellular, molecular, microcircuit, and behavioral results obtained with the valproic acid (VPA rat model of autism, we propose here a unifying hypothesis where the core pathology of the autistic brain is hyper-reactivity and hyper-plasticity of local neuronal circuits. Such excessive neuronal processing in circumscribed circuits is suggested to lead to hyper-perception, hyper-attention, and hyper-memory, which may lie at the heart of most autistic symptoms. In this view, the autistic spectrum are disorders of hyper-functionality, which turns debilitating, as opposed to disorders of hypo-functionality, as is often assumed. We discuss how excessive neuronal processing may render the world painfully intense when the neocortex is affected and even aversive when the amygdala is affected, leading to social and environmental withdrawal. Excessive neuronal learning is also hypothesized to rapidly lock down the individual into a small repertoire of secure behavioral routines that are obsessively repeated. We further discuss the key autistic neuropathologies and several of the main theories of autism and re-interpret them in the light of the hypothesized Intense World Syndrome.

  3. An epigenetic hypothesis of aging-related cognitive dysfunction

    Directory of Open Access Journals (Sweden)

    Marsha R Penner

    2010-03-01

    Full Text Available This brief review will focus on a new hypothesis for the role of epigenetic mechanisms in aging-related disruptions of synaptic plasticity and memory. Epigenetics refers to a set of potentially self-perpetuating, covalent modifications of DNA and post-translational modifications of nuclear proteins that produce lasting alterations in chromatin structure. These mechanisms, in turn, result in alterations in specific patterns of gene expression. Aging-related memory decline is manifest prominently in declarative/episodic memory and working memory, memory modalities anatomically based largely in the hippocampus and prefrontal cortex, respectively. The neurobiological underpinnings of age-related memory deficits include aberrant changes in gene transcription that ultimately affect the ability of the aged brain to be “plastic”. The molecular mechanisms underlying these changes in gene transcription are not currently known, but recent work points toward a potential novel mechanism, dysregulation of epigenetic mechanisms. This has led us to hypothesize that dysregulation of epigenetic control mechanisms and aberrant epigenetic “marks” drive aging-related cognitive dysfunction. Here we focus on this theme, reviewing current knowledge concerning epigenetic molecular mechanisms, as well as recent results suggesting disruption of plasticity and memory formation during aging. Finally, several open questions will be discussed that we believe will fuel experimental discovery.

  4. Habitat heterogeneity hypothesis and edge effects in model metacommunities.

    Science.gov (United States)

    Hamm, Michaela; Drossel, Barbara

    2017-08-07

    Spatial heterogeneity is an inherent property of any living environment and is expected to favour biodiversity due to a broader niche space. Furthermore, edges between different habitats can provide additional possibilities for species coexistence. Using computer simulations, this study examines metacommunities consisting of several trophic levels in heterogeneous environments in order to explore the above hypotheses on a community level. We model heterogeneous landscapes by using two different sized resource pools and evaluate the combined effect of dispersal and heterogeneity on local and regional species diversity. This diversity is obtained by running population dynamics and evaluating the robustness (i.e., the fraction of surviving species). The main results for regional robustness are in agreement with the habitat heterogeneity hypothesis, as the largest robustness is found in heterogeneous systems with intermediate dispersal rates. This robustness is larger than in homogeneous systems with the same total amount of resources. We study the edge effect by arranging the two types of resources in two homogeneous blocks. Different edge responses in diversity are observed, depending on dispersal strength. Local robustness is highest for edge habitats that contain the smaller amount of resource in combination with intermediate dispersal. The results show that dispersal is relevant to correctly identify edge responses on community level. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Hypothesis on the dual origin of the mammalian subplate

    Directory of Open Access Journals (Sweden)

    Juan F Montiel

    2011-04-01

    Full Text Available The development of the mammalian neocortex relies heavily on subplate. The proportion of this cell population varies considerably in different mammalian species. Subplate is almost undetectable in marsupials, forms a thin, but distinct layer in mouse and rat, a larger layer in carnivores and big-brained mammals as pig and a highly developed embryonic structure in human and non-human primates. The evolutionary origin of subplate neurons is the subject of current debate. Some hypothesize that subplate represents the ancestral cortex of sauropsids, while others consider it to be an increasingly complex phylogenetic novelty of the mammalian neocortex. Here we review recent work on expression of several genes that were originally identified in rodent as highly and differentially expressed in subplate. We relate these observations to cellular morphology, birthdating and hodology in the dorsal cortex/dorsal pallium of several amniote species. Based on this reviewed evidence we argue for a third hypothesis according to which subplate contains both ancestral and newly derived cell populations. We propose that the mammalian subplate originally derived from a phylogenetically ancient structure in the dorsal pallium of stem amniotes, but subsequently expanded with additional cell populations in the synapsid lineage to support an increasingly complex cortical plate development. Further understanding of the detailed molecular taxonomy, somatodendritic morphology and connectivity of subplate in a comparative context should contribute to the identification of the ancestral and newly evolved populations of subplate neurons.

  6. [Evolutionary process unveiled by the maximum genetic diversity hypothesis].

    Science.gov (United States)

    Huang, Yi-Min; Xia, Meng-Ying; Huang, Shi

    2013-05-01

    As two major popular theories to explain evolutionary facts, the neutral theory and Neo-Darwinism, despite their proven virtues in certain areas, still fail to offer comprehensive explanations to such fundamental evolutionary phenomena as the genetic equidistance result, abundant overlap sites, increase in complexity over time, incomplete understanding of genetic diversity, and inconsistencies with fossil and archaeological records. Maximum genetic diversity hypothesis (MGD), however, constructs a more complete evolutionary genetics theory that incorporates all of the proven virtues of existing theories and adds to them the novel concept of a maximum or optimum limit on genetic distance or diversity. It has yet to meet a contradiction and explained for the first time the half-century old Genetic Equidistance phenomenon as well as most other major evolutionary facts. It provides practical and quantitative ways of studying complexity. Molecular interpretation using MGD-based methods reveal novel insights on the origins of humans and other primates that are consistent with fossil evidence and common sense, and reestablished the important role of China in the evolution of humans. MGD theory has also uncovered an important genetic mechanism in the construction of complex traits and the pathogenesis of complex diseases. We here made a series of sequence comparisons among yeasts, fishes and primates to illustrate the concept of limit on genetic distance. The idea of limit or optimum is in line with the yin-yang paradigm in the traditional Chinese view of the universal creative law in nature.

  7. Coccospheres confer mechanical protection: New evidence for an old hypothesis.

    Science.gov (United States)

    Jaya, B N; Hoffmann, R; Kirchlechner, C; Dehm, G; Scheu, C; Langer, G

    2016-09-15

    Emiliania huxleyi has evolved an extremely intricate coccosphere architecture. The coccosphere is comprised of interlocking coccoliths embedded in a polysaccharide matrix. In this work, we performed in-situ scanning electron microscopy based compression tests and conclude that coccospheres have a mechanical protection function. The coccosphere exhibits exceptional damage tolerance in terms of inelastic deformation, recovery and stable crack growth before catastrophic fracture, a feature, which is not found in monolithic ceramic structures. Some of the mechanical features of the coccospheres are due to their architecture, especially polysaccharide matrix that acts as a kind of bio-adhesive. Our data provide strong evidence for the mechanical protection-hypothesis of coccolithophore calcification, without excluding other functions of calcification such as various biochemical roles discussed in the literature. Although bio-mechanics of shell structures like nacre have been studied over the past decade, coccospheres present an architecture that is quite distinct and complex. It is a porous cell structure evolved to protect the living algae cell inside it in the oceans, subjected to significant hydrostatic pressure. Despite being made of extremely brittle constituents like calcium carbonate, our study finds that coccospheres possess significant damage tolerance especially due to their interlocking coccolith architecture. This will have consequences in bio-mimetic design, especially relating to high pressure applications. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  8. Statistical sampling and hypothesis testing in orthopaedic research.

    Science.gov (United States)

    Bernstein, Joseph; McGuire, Kevin; Freedman, Kevin B

    2003-08-01

    The purpose of the current article was to review the process of hypothesis testing and statistical sampling and empower readers to critically appraise the literature. When the p value of a study lies above the alpha threshold, the results are said to be not statistically significant. It is possible, however, that real differences do exist, but the study was insufficiently powerful to detect them. In that case, the conclusion that two groups are equivalent is wrong. The probability of this mistake, the Type II error, is given by the beta statistic. The complement of beta, or 1-beta, representing the chance of avoiding a Type II error, is termed the statistical power of the study. We previously examined the statistical power and sample size in all of the studies published in 1997 in the American and British volumes of the Journal of Bone and Joint Surgery, and in Clinical Orthopaedics and Related Research. In the journals examined, only 3% of studies had adequate statistical power to detect a small effect size in this sample. In addition, a study examining only randomized control trials in these journals showed that none of 25 randomized control trials had adequate statistical power to detect a small effect size. However, beta, or power, is less well understood. Because of this, researchers and readers should be aware of the need to address issues of statistical power before a study begins and be cautious of studies that conclude that no difference exists between groups.

  9. The Marley hypothesis: denial of racism reflects ignorance of history.

    Science.gov (United States)

    Nelson, Jessica C; Adams, Glenn; Salter, Phia S

    2013-02-01

    This study used a signal detection paradigm to explore the Marley hypothesis--that group differences in perception of racism reflect dominant-group denial of and ignorance about the extent of past racism. White American students from a midwestern university and Black American students from two historically Black universities completed surveys about their historical knowledge and perception of racism. Relative to Black participants, White participants perceived less racism in both isolated incidents and systemic manifestations of racism. They also performed worse on a measure of historical knowledge (i.e., they did not discriminate historical fact from fiction), and this group difference in historical knowledge mediated the differences in perception of racism. Racial identity relevance moderated group differences in perception of systemic manifestations of racism (but not isolated incidents), such that group differences were stronger among participants who scored higher on a measure of racial identity relevance. The results help illuminate the importance of epistemologies of ignorance: cultural-psychological tools that afford denial of and inaction about injustice.

  10. Muon capture on Ni isotopes, projected QRPA, and CVC hypothesis

    International Nuclear Information System (INIS)

    Samana, Arturo R.; Sande, Danilo; Krmpotic, Francisco; Universidad Nacional de La Plata

    2011-01-01

    In recent years we have developed a novel formalism for the weak interaction processes, obtaining new expressions for the transition rates, which greatly facilitate numerical calculations, for both neutrino-nucleus reactions and muon capture, allowing us to use very large configuration spaces and to evaluate the quasielastic 12 C (ν, μ - ) 12 N cross section at energies of the order of 1 GeV, which are measured in the MiniBooNE experiment. Our formulation includes for the first time the consequences of the explicit violation of the conserved vector current (CVC) hypothesis by the Coulomb field. We have also shown that the particle number projection procedure within the quasiparticle random phase approximation (QRPA) is important in describing the exclusive (ground-state) properties of 12 B and 12 N as well as the muon capture rate and the neutrino nucleus cross section in 56 Fe. In this work, we analyze in a quantitative way the consequences of the CVC violation on the muon capture rates in Ni isotopes (for which are available the experimental data) using both the standard QRPA and the projected QRPA (PQRPA). The last one is the only RPA model that treats the Pauli Principle correctly, and we demonstrate that the number projection procedure is important not only for light nuclei but also for medium heavy ones that were studied here. (author)

  11. Behavioral excesses in depression: a learning theory hypothesis.

    Science.gov (United States)

    Dygdon, Judith A; Dienes, Kimberly A

    2013-06-01

    This paper reviews two learning theory-based models of experiential contributions to depression: response contingent positive reinforcement and learned helplessness. The authors argue that these models connect to a phenomenon that may explain why symptoms of behavioral excess (e.g. rumination) often occur in depression that is otherwise marked by symptoms of behavioral deficit (e.g. anhedonia). Specifically, the authors illustrate that that concept of schedule strain (or low rates of response contingent reinforcement giving rise to low frequencies of behavior) unites these models. Depression is more likely, or more severe, when schedule strain conditions occur in situations containing reinforcers important to the individual and/or when they simultaneously occur in a number of situations. Conditions of schedule strain are known to give rise to adjunctive behaviors: apparently irrelevant, easy behaviors that deliver immediate reinforcement. This paper suggests that, for some depressed individuals, behavioral excess symptoms like rumination and overeating might serve adjunctive functions. Implications of this hypothesis are discussed. © 2013 Wiley Periodicals, Inc.

  12. The linear hypothesis: An idea whose time has passed

    International Nuclear Information System (INIS)

    Tschaeche, A.N.

    1995-01-01

    This paper attempts to present a clear idea of what the linear (no-threshold) hypothesis (LH) is, how it was corrupted and what happened to the nuclear industry as a result, and one possible solution to this major problem for the nuclear industry. The corruption lies in the change of the LH from ''a little radiation MAY produce harm'' to ''low doses of radiation WILL KILL you.'' The result has been the retardation of the nuclear industry in the United States, although the industry is one of the safest, if not the safest industry. It is suggested to replace the LH with two sets of standards, one having to do with human and environmental health and safety, and the other (more stringent) for protection of manufactured items and premises. The safety standard could be some dose such as 5 rem/year. This would do away with the ALARA concept below the annual limit and with the collective dose at low doses. Benefits of the two-tier radiation standards system would be the alleviation of the public fear of radiation and the health of the nuclear industry

  13. Organization of haemopoietic stem cells: the generation-age hypothesis

    International Nuclear Information System (INIS)

    Rosendaal, M.; Hodgson, G.S.; Bradley, T.R.

    1978-01-01

    This paper proposes that the previous division history of each stem cell is one determinant of the functional organisation of the haemopoietic stem cell population. Older stem cell are used to form blood before younger ones. The stem cells generating capacity of a lineage is finite, and cells are eventually lost to the system by forming two committed precursors of the cell lines, and the next oldest stem cell takes over. Hence the proposed term 'generation-age hypothesis', supported by experimental evidence. Older stem cells from normal bone marrow and 13 day foetal liver were stripped away with phase-specific drugs revealing a younger population of stem cells with three-to four-fold greater stem cell generating capacity. Normal stem cells aged by continuous irradiation and serial retransplantation had eight-fold reduced generating capacity. That of stem cells in the bloodstream was half to a quarter that of normal bone marrow stem cells. There were some circulating stem cells, identified by reaction to brain-associated antigen, positive for 75% of normal femoral stem cells but not their progeny, whose capacity for stem cell generation was an eighth to one fortieth that of normal cells. (U.K.)

  14. Early hominins in Europe: The Galerian migration hypothesis

    Science.gov (United States)

    Muttoni, Giovanni; Scardia, Giancarlo; Kent, Dennis V.

    2018-01-01

    Our updated review of sites bearing hominin remains and/or tools from Europe, including new findings from the Balkans, still indicates that the only compelling evidence of main hominin presence in these regions was only since ∼0.9 million years ago (Ma), bracketed by the end of the Jaramillo geomagnetic polarity subchron (0.99 Ma) and the Brunhes-Matuyama polarity chron boundary (0.78 Ma). This time window straddled the late Early Pleistocene climate transition (EPT) at the onset of enhanced glacial/interglacial activity that reverberated worldwide. Europe may have become initially populated during the EPT when, possibly for the first time in the Pleistocene, vast and exploitable ecosystems were generated along the eustatically emergent Po-Danube terrestrial conduit. These newly formed settings, characterized by stable terrestrial lowlands with open grasslands and reduced woody cover especially during glacial/interglacial transitions, are regarded as optimal ecosystems for several large Galerian immigrant mammals such as African and Asian megaherbivores, possibly linked with hominins in a common food web, to expand into en route to Europe. The question of when hominins first arrived in Europe thus places the issue in the context of changes in climate, paleogeography and faunal associations as potential environmental drivers and controlling agents in a specific time frame, a key feature of the Galerian migration hypothesis.

  15. A hypothesis concerning the nature of dark matter

    International Nuclear Information System (INIS)

    Paduroiu, Sinziana; Rusu, Mircea

    2004-01-01

    In this paper we briefly review the main observational facts that lead to the hypothesis of the so called 'dark matter' as a considerable part of the matter in the Universe that is not visible. The expansion rate of the universe, the birth of the galaxies and their rotation curves are some of the phenomena that can be explained by the existence of dark matter. Generally, there are two models for dark matter: the hot dark matter (HDM) model and the cold dark matter one (CDM). In this paper we will refer mainly to the cold dark matter model. Two different opinions regarding the nature of dark matter and its contribution to the total mass of the matter in the Universe due to a cosmological constant will be discussed. In the first part some particles candidates for dark matter like neutralino and axions will be considered and their prediction made by supersymmetry theory. In the second part different alternative models will be presented that imply singularities of the gravitational theory; inflationary models; and in particular one model that introduces a new expression in the gravitational potential as an attempt to explain the phenomena that made us believe in the existence of this kind of matter. (authors)

  16. Anosognosia as motivated unawareness: the 'defence' hypothesis revisited.

    Science.gov (United States)

    Turnbull, Oliver H; Fotopoulou, Aikaterini; Solms, Mark

    2014-12-01

    Anosognosia for hemiplegia has seen a century of almost continuous research, yet a definitive understanding of its mechanism remains elusive. Essentially, anosognosic patients hold quasi-delusional beliefs about their paralysed limbs, in spite of all the contrary evidence, repeated questioning, and logical argument. We review a range of findings suggesting that emotion and motivation play an important role in anosognosia. We conclude that anosognosia involves (amongst other things) a process of psychological defence. This conclusion stems from a wide variety of clinical and experimental investigations, including data on implicit awareness of deficit, fluctuations in awareness over time, and dramatic effects upon awareness of psychological interventions such as psychotherapy, reframing of the emotional consequences of the paralysis, and first versus third person perspectival manipulations. In addition, we review and refute the (eight) arguments historically raised against the 'defence' hypothesis, including the claim that a defence-based account cannot explain the lateralised nature of the disorder. We argue that damage to a well-established right-lateralised emotion regulation system, with links to psychological processes that appear to underpin allocentric spatial cognition, plays a key role in anosognosia (at least in some patients). We conclude with a discussion of implications for clinical practice. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. The fetal programming of telomere biology hypothesis: an update.

    Science.gov (United States)

    Entringer, Sonja; de Punder, Karin; Buss, Claudia; Wadhwa, Pathik D

    2018-03-05

    Research on mechanisms underlying fetal programming of health and disease risk has focused primarily on processes that are specific to cell types, organs or phenotypes of interest. However, the observation that developmental conditions concomitantly influence a diverse set of phenotypes, the majority of which are implicated in age-related disorders, raises the possibility that such developmental conditions may additionally exert effects via a common underlying mechanism that involves cellular/molecular ageing-related processes. In this context, we submit that telomere biology represents a process of particular interest in humans because, firstly, this system represents among the most salient antecedent cellular phenotypes for common age-related disorders; secondly, its initial (newborn) setting appears to be particularly important for its long-term effects; and thirdly, its initial setting appears to be plastic and under developmental regulation. We propose that the effects of suboptimal intrauterine conditions on the initial setting of telomere length and telomerase expression/activity capacity may be mediated by the programming actions of stress-related maternal-placental-fetal oxidative, immune, endocrine and metabolic pathways in a manner that may ultimately accelerate cellular dysfunction, ageing and disease susceptibility over the lifespan. This perspectives paper provides an overview of each of the elements underlying this hypothesis, with an emphasis on recent developments, findings and future directions.This article is part of the theme issue 'Understanding diversity in telomere dynamics'. © 2018 The Author(s).

  18. Counselor Hypothesis Testing Strategies: The Role of Initial Impressions and Self-Schema.

    Science.gov (United States)

    Strohmer, Douglas C.; Chiodo, Anthony L.

    1984-01-01

    Presents two experiments concerning confirmatory bias in the way counselors collect data to test their hypotheses. Counselors were asked either to develop their own clinical hypothesis or were given a hypothesis to test. Confirmatory bias in hypothesis testing was not supported in either experiment. (JAC)

  19. Personal Hypothesis Testing: The Role of Consistency and Self-Schema.

    Science.gov (United States)

    Strohmer, Douglas C.; And Others

    1988-01-01

    Studied how individuals test hypotheses about themselves. Examined extent to which Snyder's bias toward confirmation persists when negative or nonconsistent personal hypothesis is tested. Found negativity or positivity did not affect hypothesis testing directly, though hypothesis consistency did. Found cognitive schematic variable (vulnerability…

  20. The Variability Hypothesis: The History of a Biological Model of Sex Differences in Intelligence.

    Science.gov (United States)

    Shields, Stephanie A.

    1982-01-01

    Describes the origin and development of the variability hypothesis as applied to the study of social and psychological sex differences. Explores changes in the hypothesis over time, social and scientific factors that fostered its acceptance, and possible parallels between the variability hypothesis and contemporary theories of sex differences.…

  1. The Cognitive Mediation Hypothesis Revisited: An Empirical Response to Methodological and Theoretical Criticism.

    Science.gov (United States)

    Romero, Anna A.; And Others

    1996-01-01

    In order to address criticisms raised against the cognitive mediation hypothesis, three experiments were conducted to develop a more direct test of the hypothesis. Taken together, the three experiments provide converging support for the cognitive mediation hypothesis, reconfirming the central role of cognition in the persuasion process.…

  2. Why Do Fast-Growing Bacteria Enter Overflow Metabolism? Testing the Membrane Real Estate Hypothesis.

    Science.gov (United States)

    Szenk, Mariola; Dill, Ken A; de Graff, Adam M R

    2017-08-23

    Bacteria and other cells show a puzzling behavior. At high growth rates, E. coli switch from respiration (which is ATP-efficient) to using fermentation for additional ATP (which is inefficient). This overflow metabolism results in a several-fold decrease in ATP produced per glucose molecule provided as food. By integrating diverse types of experimental data into a simple biophysical model, we give evidence that this onset is the result of the membrane real estate hypothesis: Fast growth drives cells to be bigger, reducing their surface-to-volume ratios. This decreases the membrane area available for respiratory proteins despite growing demand, causing increased crowding. Only when respiratory proteins reach their crowding limit does the cell activate fermentation, since fermentation allows faster ATP production per unit membrane area. Surface limitation thus creates a Pareto trade-off between membrane efficiency and ATP yield that links metabolic choice to the size and shape of a bacterial cell. By exploring the predictions that emerge from this trade-off, we show how consideration of molecular structures, energetics, rates, and equilibria can provide important insight into cellular behavior. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Cumulative risk hypothesis: Predicting and preventing child maltreatment recidivism.

    Science.gov (United States)

    Solomon, David; Åsberg, Kia; Peer, Samuel; Prince, Gwendolyn

    2016-08-01

    Although Child Protective Services (CPS) and other child welfare agencies aim to prevent further maltreatment in cases of child abuse and neglect, recidivism is common. Having a better understanding of recidivism predictors could aid in preventing additional instances of maltreatment. A previous study identified two CPS interventions that predicted recidivism: psychotherapy for the parent, which was related to a reduced risk of recidivism, and temporary removal of the child from the parent's custody, which was related to an increased recidivism risk. However, counter to expectations, this previous study did not identify any other specific risk factors related to maltreatment recidivism. For the current study, it was hypothesized that (a) cumulative risk (i.e., the total number of risk factors) would significantly predict maltreatment recidivism above and beyond intervention variables in a sample of CPS case files and that (b) therapy for the parent would be related to a reduced likelihood of recidivism. Because it was believed that the relation between temporary removal of a child from the parent's custody and maltreatment recidivism is explained by cumulative risk, the study also hypothesized that that the relation between temporary removal of the child from the parent's custody and recidivism would be mediated by cumulative risk. After performing a hierarchical logistic regression analysis, the first two hypotheses were supported, and an additional predictor, psychotherapy for the child, also was related to reduced chances of recidivism. However, Hypothesis 3 was not supported, as risk did not significantly mediate the relation between temporary removal and recidivism. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Testing Kuznets’ Hypothesis for Russian Regions: Trends and Interpretations

    Directory of Open Access Journals (Sweden)

    James R. Alm

    2016-06-01

    Full Text Available The paper established a number of "stylized facts", one of which is a confirmation of the S. Kuznets’ hypothesis of the nonlinear dependence between the degree of inequality in income distribution and welfare economic systems on the example of a group of Russian regions for the period 2002–2012. It is shown that, for a given sample, the welfare and economic growth factors amplify their influence on inequality in income distribution in the post-crisis period. The monotonous growth of income inequality which was observed before the crisis of 2008 is slowing in the process of raising the per capita gross regional product (GRP during the post-crisis period, and for the foreseeable future, in some regions, its direction can be reversed, while maintaining a trend of socio-economic development. Despite the persistence over time of a convex nature of S. Kuznets’ curve for Russian regional data, its parameters changed during the reporting 2002–2012 period. The maximum point of the curve shifts to the left, its convexity increases. These facts indicate that the income inequality growth of the Russian regions’ as a result of growth of per capita GRP is slowing. For some regions in the post-crisis period, the income inequality does not grow with the growth of per capita GRP, or it even reduces. This fact can be attributed to the implementation of the Russian federal socially oriented projects and programs in recent years. The results can be used for the development of regional economic policy in order to regulate the level of income distribution inequality in the regions of Russia.

  5. Language and emotions: emotional Sapir-Whorf hypothesis.

    Science.gov (United States)

    Perlovsky, Leonid

    2009-01-01

    An emotional version of Sapir-Whorf hypothesis suggests that differences in language emotionalities influence differences among cultures no less than conceptual differences. Conceptual contents of languages and cultures to significant extent are determined by words and their semantic differences; these could be borrowed among languages and exchanged among cultures. Emotional differences, as suggested in the paper, are related to grammar and mostly cannot be borrowed. The paper considers conceptual and emotional mechanisms of language along with their role in the mind and cultural evolution. Language evolution from primordial undifferentiated animal cries is discussed: while conceptual contents increase, emotional reduced. Neural mechanisms of these processes are suggested as well as their mathematical models: the knowledge instinct, the dual model connecting language and cognition, neural modeling fields. Mathematical results are related to cognitive science, linguistics, and psychology. Experimental evidence and theoretical arguments are discussed. Dynamics of the hierarchy-heterarchy of human minds and cultures is formulated using mean-field approach and approximate equations are obtained. The knowledge instinct operating in the mind heterarchy leads to mechanisms of differentiation and synthesis determining ontological development and cultural evolution. These mathematical models identify three types of cultures: "conceptual" pragmatic cultures in which emotionality of language is reduced and differentiation overtakes synthesis resulting in fast evolution at the price of uncertainty of values, self doubts, and internal crises; "traditional-emotional" cultures where differentiation lags behind synthesis, resulting in cultural stability at the price of stagnation; and "multi-cultural" societies combining fast cultural evolution and stability. Unsolved problems and future theoretical and experimental directions are discussed.

  6. A critical review of Dunbar’s social brain hypothesis

    Directory of Open Access Journals (Sweden)

    Acedo-Carmona, Cristina

    2016-09-01

    Full Text Available Dunbar’s social brain hypothesis constitutes an influential position among those that relate the evolution of human cognition and sociality. In this work, we first present the essentials of the theory and discuss the paleoanthropological and social evidence claimed to support it. We also point out its shortcomings, which have to do with the general strategy of finding linear relations among different traits, the lack of attention to the mental capacities that make human social life possible, and the diversity of social relations and structures that take place. We put forward our way of complementing Dunbar’s approach by focusing on the role of trust in cementing society and explaining diversity.La hipótesis del cerebro social de Dunbar constituye una posición influyente entre aquellas que relacionan la evolución de la cognición y la socialidad humanas. En este trabajo, tras presentar los puntos esenciales de su teoría, discutimos las evidencias paleo-antropológicas y sociales en las que se sustenta. También señalamos algunas limitaciones. Tales limitaciones tienen que ver con la estrategia general de buscar relaciones lineales entre diferentes rasgos, la insuficiente atención a las capacidades mentales que hacen posible la vida social humana, y a la diversidad de las estructuras sociales efectivas. Presentamos nuestra forma de complementar el enfoque de Dunbar al centrarnos en el papel que juega la confianza como cemento de la sociedad y para explicar la diversidad

  7. Dental pain induced by an ambient thermal differential: pathophysiological hypothesis

    Directory of Open Access Journals (Sweden)

    Le Fur-Bonnabesse A

    2017-12-01

    Full Text Available Anaïs Le Fur-Bonnabesse,1,2 Céline Bodéré,1–3 Cyrielle Hélou,2 Valérie Chevalier,2,4 Jean-Paul Goulet5 1Laboratory of Neurosciences of Brest (EA4685, University of Western Brittany, Brest, France; 2Dental School, University of Western Brittany, Brest, France; 3Assessment and Treatment Center of Pain, Regional and University Hospital Center, Brest, France; 4Laboratory IRDL, FRE CNRS 3744, University of Western Brittany, Brest, France; 5School of Dental Medicine, Universite Laval, Quebec, QC, Canada Abstract: Dental pain triggered by temperature differential is a misrecognized condition and a form of dental allodynia. Dental allodynia is characterized by recurrent episodes of diffuse, dull and throbbing tooth pain that develops when returning to an indoor room temperature after being exposed for a long period to cold weather. The pain episode may last up to few hours before subsiding. Effective treatment is to properly shield the pulpal tissue of the offending tooth by increasing the protective layer of the dentin/enamel complex. This review underscores the difference in dentin hypersensitivity and offers a mechanistic hypothesis based on the following processes. Repeated exposure to significant positive temperature gradients (from cold to warm generates phenotypic changes of dental primary afferents on selected teeth with subsequent development of a “low-grade” neurogenic inflammation. As a result, nociceptive C-fibers become sensitized and responsive to innocuous temperature gradients because the activation threshold of specific TRP ion channels is lowered and central sensitization takes place. Comprehensive overviews that cover dental innervation and sensory modalities, thermodynamics of tooth structure, mechanisms of dental nociception and the thermal pain are also provided. Keywords: pain, dental pain, thermal allodynia, atypical tooth sensitivity, dentin hypersensitivity 

  8. ON THE DARWINIAN HYPOTHESIS OF THE ADAPTIVE SIGNIFICANCE OF TRISTYLY.

    Science.gov (United States)

    Barrett, Spencer C H; Glover, Deborah E

    1985-07-01

    Darwin proposed that the function of the stamen-style polymorphism in heterostylous plants is to increase the probability of legitimate (compatible) pollinations among the floral morphs. Conspicuous pollen trimorphism in tristylous Pontederia cordata enables a test of the hypothesis. Comparison of the composition of pollen loads in naturally pollinated stigmas of intact and emasculated flowers were made at a population in Paugh Lake, Ontario, which was visited primarily by bumblebees. The magnitude of legitimate pollination was analyzed by ANOVA. In intact flowers, significant legitimate pollination was detected in the long-styled morph only. Following emasculation legitimate pollination was evident in the long- and short-styled morphs, with the mid-styled morph just short of displaying significant legitimate pollination. Similar results were obtained by chi-square analysis. It has been suggested that heterostyly may reduce mutual interference between maternal and paternal reproductive function. Two aspects of pollen-stigma interference were investigated in P. cordata. The potential importance of stigmatic or stylar clogging by incompatible pollen was examined by controlled field pollinations and measurements of seed set. The results indicate that prior application of large amounts of incompatible pollen has no significant effect on the seed set of open-pollinated inflorescences. Comparison of legitimate pollen capture in intact and emasculated flowers provided no evidence that the presence of stamens within flowers of the floral morphs interferes with the receipt of legitimate pollen. Pollen-stigma interference remains to be demonstrated in heterostylous plants. © 1985 The Society for the Study of Evolution.

  9. The minimum transition hypothesis for intermittent hierarchical motor control.

    Science.gov (United States)

    Karniel, Amir

    2013-01-01

    In intermittent control, instead of continuously calculating the control signal, the controller occasionally changes this signal at certain sparse points in time. The control law may include feedback, adaptation, optimization, or any other control strategies. When, where, and how does the brain employ intermittency as it controls movement? These are open questions in motor neuroscience. Evidence for intermittency in human motor control has been repeatedly observed in the neural control of movement literature. Moreover, some researchers have provided theoretical models to address intermittency. Even so, the vast majority of current models, and I would dare to say the dogma in most of the current motor neuroscience literature involves continuous control. In this paper, I focus on an area in which intermittent control has not yet been thoroughly considered, the structure of muscle synergies. A synergy in the muscle space is a group of muscles activated together by a single neural command. Under the assumption that the motor control is intermittent, I present the minimum transition hypothesis (MTH) and its predictions with regards to the structure of muscle synergies. The MTH asserts that the purpose of synergies is to minimize the effort of the higher level in the hierarchy by minimizing the number of transitions in an intermittent control signal. The implications of the MTH are not only for the structure of the muscle synergies but also to the intermittent and hierarchical nature of the motor system, with various predictions as to the process of skill learning, and important implications to the design of brain machine interfaces and human robot interaction.

  10. A global test of the pollination syndrome hypothesis.

    Science.gov (United States)

    Ollerton, Jeff; Alarcón, Ruben; Waser, Nickolas M; Price, Mary V; Watts, Stella; Cranmer, Louise; Hingston, Andrew; Peter, Craig I; Rotenberry, John

    2009-06-01

    'Pollination syndromes' are suites of phenotypic traits hypothesized to reflect convergent adaptations of flowers for pollination by specific types of animals. They were first developed in the 1870s and honed during the mid 20th Century. In spite of this long history and their central role in organizing research on plant-pollinator interactions, the pollination syndromes have rarely been subjected to test. The syndromes were tested here by asking whether they successfully capture patterns of covariance of floral traits and predict the most common pollinators of flowers. Flowers in six communities from three continents were scored for expression of floral traits used in published descriptions of the pollination syndromes, and simultaneously the pollinators of as many species as possible were characterized. Ordination of flowers in a multivariate 'phenotype space' defined by the syndromes showed that almost no plant species fall within the discrete syndrome clusters. Furthermore, in approximately two-thirds of plant species, the most common pollinator could not be successfully predicted by assuming that each plant species belongs to the syndrome closest to it in phenotype space. The pollination syndrome hypothesis as usually articulated does not successfully describe the diversity of floral phenotypes or predict the pollinators of most plant species. Caution is suggested when using pollination syndromes for organizing floral diversity, or for inferring agents of floral adaptation. A fresh look at how traits of flowers and pollinators relate to visitation and pollen transfer is recommended, in order to determine whether axes can be identified that describe floral functional diversity more successfully than the traditional syndromes.

  11. Backcasting long-term climate data: evaluation of hypothesis

    Science.gov (United States)

    Saghafian, Bahram; Aghbalaghi, Sara Ghasemi; Nasseri, Mohsen

    2018-05-01

    Most often than not, incomplete datasets or short-term recorded data in vast regions impedes reliable climate and water studies. Various methods, such as simple correlation with stations having long-term time series, are practiced to infill or extend the period of observation at stations with missing or short-term data. In the current paper and for the first time, the hypothesis on the feasibility of extending the downscaling concept to backcast local observation records using large-scale atmospheric predictors is examined. Backcasting is coined here to contrast forecasting/projection; the former is implied to reconstruct in the past, while the latter represents projection in the future. To assess our hypotheses, daily and monthly statistical downscaling models were employed to reconstruct past precipitation data and lengthen the data period. Urmia and Tabriz synoptic stations, located in northwestern Iran, constituted two case study stations. SDSM and data-mining downscaling model (DMDM) daily as well as the group method of data handling (GMDH) and model tree (Mp5) monthly downscaling models were trained with National Center for Environmental Prediction (NCEP) data. After training, reconstructed precipitation data of the past was validated against observed data. Then, the data was fully extended to the 1948 to 2009 period corresponding to available NCEP data period. The results showed that DMDM performed superior in generation of monthly average precipitation compared with the SDSM, Mp5, and GMDH models, although none of the models could preserve the monthly variance. This overall confirms practical value of the proposed approach in extension of the past historic data, particularly for long-term climatological and water budget studies.

  12. Backcasting long-term climate data: evaluation of hypothesis

    Science.gov (United States)

    Saghafian, Bahram; Aghbalaghi, Sara Ghasemi; Nasseri, Mohsen

    2017-04-01

    Most often than not, incomplete datasets or short-term recorded data in vast regions impedes reliable climate and water studies. Various methods, such as simple correlation with stations having long-term time series, are practiced to infill or extend the period of observation at stations with missing or short-term data. In the current paper and for the first time, the hypothesis on the feasibility of extending the downscaling concept to backcast local observation records using large-scale atmospheric predictors is examined. Backcasting is coined here to contrast forecasting/projection; the former is implied to reconstruct in the past, while the latter represents projection in the future. To assess our hypotheses, daily and monthly statistical downscaling models were employed to reconstruct past precipitation data and lengthen the data period. Urmia and Tabriz synoptic stations, located in northwestern Iran, constituted two case study stations. SDSM and data-mining downscaling model (DMDM) daily as well as the group method of data handling (GMDH) and model tree (Mp5) monthly downscaling models were trained with National Center for Environmental Prediction (NCEP) data. After training, reconstructed precipitation data of the past was validated against observed data. Then, the data was fully extended to the 1948 to 2009 period corresponding to available NCEP data period. The results showed that DMDM performed superior in generation of monthly average precipitation compared with the SDSM, Mp5, and GMDH models, although none of the models could preserve the monthly variance. This overall confirms practical value of the proposed approach in extension of the past historic data, particularly for long-term climatological and water budget studies.

  13. [Hepatitis C, interferon a and depression: main physiopathologic hypothesis].

    Science.gov (United States)

    Vignau, J; Karila, L; Costisella, O; Canva, V

    2005-01-01

    classically involved in depression pathophysiology, other works have demonstrated that IFNalpha modulates the peripheral activity of indolamine-dioxygenase -- a regulating enzyme of serotonin metabolism -- possibly through lymphocyte T CD4 activation. Third, other authors have postulated an immune-induced vagal mechanism to explain depression caused by IFNalpha. Action of IFNalpha on the neuroendocrine and on neuromodulating functions: monoaminergic hypothesis -- cytokines could have an influence on the mood through their modulating role on the serotoninergic system. IFNalpha treatment is reported to produce: 1) a decrease in tryptophan availability for serotonin synthesis, 2) a decrease in the 5-HIAA level in the LCR, and 3) a modification of the central serotoninergic receptors. Moreover, selective inhibitors of serotonin transporters are effective to treat or prevent depression caused by IFNalpha. Many studies support the serotonin-transporter hypothesis: in vitro, both IFNalpha and interleukine 4 (IL-4) increases the expression of serotonin transporter gene, IFNalpha increases in the production of IL-4 by mononucleus cells (not found in vivo). Serotoninergic system can also be altered by a peripheral action of IFNalpha on trytophan catabolism by activating a concurrent pathway (known as "kynurenine pathway") to serotonin synthesis. Finally, serotonin-mediated vulnerability to the psychobehavioural effects of IFNalpha could be underlain by a polymorphism of serotonin transporter gene. Concerning the other monoaminergic systems, IFNalpha seems to have an amphetamine-like effect at its first administration, followed by a decrease in dopaminergic tone with chronic administration. Dopaminergic depletion, subsequent to psychostimulant abuse for instance, results in severe depressive syndromes. Interactions between IFNalpha and noradrenergic system have also been reported. Neuroendocrinian hypothesis -- when administered through central or peripheral way, IFNalpha simulates

  14. Surface-to-surface registration using level sets

    DEFF Research Database (Denmark)

    Hansen, Mads Fogtmann; Erbou, Søren G.; Vester-Christensen, Martin

    2007-01-01

    problem can be approximated by the image registration (IR) problem of the signed distance maps (SDMs) of the surfaces confined to some narrow band. By shrinking the narrow bands around the zero level sets the solution to the IR problem converges towards the S2SR problem. It is our hypothesis...... that this approach is more robust and less prone to fall into local minima than ordinary surface-to-surface registration. The IR problem is solved using the inverse compositional algorithm. In this paper, a set of 40 pelvic bones of Duroc pigs are registered to each other w.r.t. the Euclidean transformation...

  15. Structure based hypothesis of a mitochondrial ribosome rescue mechanism

    Directory of Open Access Journals (Sweden)

    Huynen Martijn A

    2012-05-01

    Full Text Available Abstract Background mtRF1 is a vertebrate mitochondrial protein with an unknown function that arose from a duplication of the mitochondrial release factor mtRF1a. To elucidate the function of mtRF1, we determined the positions that are conserved among mtRF1 sequences but that are different in their mtRF1a paralogs. We subsequently modeled the 3D structure of mtRF1a and mtRF1 bound to the ribosome, highlighting the structural implications of these differences to derive a hypothesis for the function of mtRF1. Results Our model predicts, in agreement with the experimental data, that the 3D structure of mtRF1a allows it to recognize the stop codons UAA and UAG in the A-site of the ribosome. In contrast, we show that mtRF1 likely can only bind the ribosome when the A-site is devoid of mRNA. Furthermore, while mtRF1a will adopt its catalytic conformation, in which it functions as a peptidyl-tRNA hydrolase in the ribosome, only upon binding of a stop codon in the A-site, mtRF1 appears specifically adapted to assume this extended, peptidyl-tRNA hydrolyzing conformation in the absence of mRNA in the A-site. Conclusions We predict that mtRF1 specifically recognizes ribosomes with an empty A-site and is able to function as a peptidyl-tRNA hydrolase in those situations. Stalled ribosomes with empty A-sites that still contain a tRNA bound to a peptide chain can result from the translation of truncated, stop-codon less mRNAs. We hypothesize that mtRF1 recycles such stalled ribosomes, performing a function that is analogous to that of tmRNA in bacteria. Reviewers This article was reviewed by Dr. Eugene Koonin, Prof. Knud H. Nierhaus (nominated by Dr. Sarah Teichmann and Dr. Shamil Sunyaev.

  16. SETI in vivo: testing the we-are-them hypothesis

    Science.gov (United States)

    Makukov, Maxim A.; Shcherbak, Vladimir I.

    2018-04-01

    After it was proposed that life on Earth might descend from seeding by an earlier extraterrestrial civilization motivated to secure and spread life, some authors noted that this alternative offers a testable implication: microbial seeds could be intentionally supplied with a durable signature that might be found in extant organisms. In particular, it was suggested that the optimal location for such an artefact is the genetic code, as the least evolving part of cells. However, as the mainstream view goes, this scenario is too speculative and cannot be meaningfully tested because encoding/decoding a signature within the genetic code is something ill-defined, so any retrieval attempt is doomed to guesswork. Here we refresh the seeded-Earth hypothesis in light of recent observations, and discuss the motivation for inserting a signature. We then show that `biological SETI' involves even weaker assumptions than traditional SETI and admits a well-defined methodological framework. After assessing the possibility in terms of molecular and evolutionary biology, we formalize the approach and, adopting the standard guideline of SETI that encoding/decoding should follow from first principles and be convention-free, develop a universal retrieval strategy. Applied to the canonical genetic code, it reveals a non-trivial precision structure of interlocked logical and numerical attributes of systematic character (previously we found these heuristically). To assess this result in view of the initial assumption, we perform statistical, comparison, interdependence and semiotic analyses. Statistical analysis reveals no causal connection of the result to evolutionary models of the genetic code, interdependence analysis precludes overinterpretation, and comparison analysis shows that known variations of the code lack any precision-logic structures, in agreement with these variations being post-LUCA (i.e. post-seeding) evolutionary deviations from the canonical code. Finally, semiotic

  17. The Logic and Realism of the Hypothesis of Exploitation Ecosystems.

    Science.gov (United States)

    Oksanen, Lauri; Oksanen, Tarja

    2000-06-01

    Hypotheses on trophic dynamics in terrestrial ecosystems fall into two major categories: those in which plants are assumed to be invulnerable to their consumers and those in which the build-up of plant biomass is assumed to require top-down control of folivores. The hypothesis of exploitation ecosystems (EEH) belongs to the latter category and focuses particularly on the consequences of the high energetic costs of maintenance of endotherms. Carnivorous endotherms require relatively high prey densities in order to break even. Moreover, they are dependent on folivorous prey during the limiting season, at least at high latitudes. The endotherm branch of the grazing web is thus predicted to collapse from three-link trophic dynamics (carnivores → folivores → plants → inorganic resources) to two-link dynamics (folivores → plants → inorganic resources) along gradients of decreasing primary productivity. Consequently, the vegetation of cold and unproductive areas is predicted to be under intense winter grazing pressure, which prevents the accumulation of aboveground plant biomass and excludes erect woody plants. In the most extreme habitats (e.g., polar deserts and their high alpine counterparts), even folivorous endotherms are predicted to be absent, and the scanty vegetation is predicted to be structured by preemptive competition. Within temperature-determined productivity gradients, EEH is corroborated by biomass patterns, by patterns in the structure and dynamics of carnivore, folivore, and plant communities, and by experimental results. The general idea of top-down trophic dynamics is supported for other autotroph-based systems, too, but the relevance and sufficiency of the energy constraint in explaining patterns in trophic dynamics appears to be variable. Moreover, critical empirical evidence for or against the capacity of folivorous insects to regulate plant biomass has not yet been obtained. Another open question is the ability of boreal and temperate

  18. The hygiene hypothesis: current perspectives and future therapies

    Directory of Open Access Journals (Sweden)

    Stiemsma LT

    2015-07-01

    Full Text Available Leah T Stiemsma,1,2 Lisa A Reynolds,3 Stuart E Turvey,1,2,4 B Brett Finlay1,3,5 1Department of Microbiology & Immunology, University of British Columbia, 2The Child and Family Research Institute, 3Michael Smith Laboratories, University of British Columbia, 4Department of Pediatrics, University of British Columbia, 5Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada Abstract: Developed countries have experienced a steady increase in atopic disease and disorders of immune dysregulation since the 1980s. This increase parallels a decrease in infectious diseases within the same time period, while developing countries seem to exhibit the opposite effect, with less immune dysregulation and a higher prevalence of infectious disease. The “hygiene hypothesis”, proposed by Strachan in 1989, aimed to explain this peculiar generational rise in immune dysregulation. However, research over the past 10 years provides evidence connecting the commensal and symbiotic microbes (intestinal microbiota and parasitic helminths with immune development, expanding the hygiene hypothesis into the “microflora” and “old friends” hypotheses, respectively. There is evidence that parasitic helminths and commensal microbial organisms co-evolved with the human immune system and that these organisms are vital in promoting normal immune development. Current research supports the potential for manipulation of the bacterial intestinal microbiota to treat and even prevent immune dysregulation in the form of atopic disease and other immune-mediated disorders (namely inflammatory bowel disease and type 1 diabetes. Both human and animal model research are crucial in understanding the mechanistic links between these intestinal microbes and helminth parasites, and the human immune system. Pro-, pre-, and synbiotic, as well as treatment with live helminth and excretory/secretory helminth product therapies, are all potential

  19. The Implications of Tides on the Mimas Ocean Hypothesis

    Science.gov (United States)

    Rhoden, Alyssa Rose; Henning, Wade; Hurford, Terry A.; Patthoff, D. Alex; Tajeddine, Radwan

    2017-01-01

    We investigate whether a present-day global ocean within Mimas is compatible with the lack of tectonic activity on its surface by computing tidal stresses for ocean-bearing interior structure models derived from observed librations. We find that, for the suite of compatible rheological models, peak surface tidal stresses caused by Mimas' high eccentricity would range from a factor of 2 smaller to an order of magnitude larger than those on tidally active Europa. Thermal stresses from a freezing ocean, or a past higher eccentricity, would enhance present-day tidal stresses, exceeding the magnitudes associated with Europa's ubiquitous tidally driven fractures and, in some cases, the failure strength of ice in laboratory studies. Therefore, in order for Mimas to have an ocean, its ice shell cannot fail at the stress values implied for Europa. Furthermore, if Mimas' ocean is freezing out, the ice shell must also be able to withstand thermal stresses that could be an order of magnitude higher than the failure strength of laboratory ice samples. In light of these challenges, we consider an ocean-free Mimas to be the most straightforward model, best supported by our tidal stress analysis.

  20. Applying the cost of generating force hypothesis to uphill running

    Directory of Open Access Journals (Sweden)

    Wouter Hoogkamer

    2014-07-01

    Full Text Available Historically, several different approaches have been applied to explain the metabolic cost of uphill human running. Most of these approaches result in unrealistically high values for the efficiency of performing vertical work during running uphill, or are only valid for running up steep inclines. The purpose of this study was to reexamine the metabolic cost of uphill running, based upon our understanding of level running energetics and ground reaction forces during uphill running. In contrast to the vertical efficiency approach, we propose that during incline running at a certain velocity, the forces (and hence metabolic energy required for braking and propelling the body mass parallel to the running surface are less than during level running. Based on this idea, we propose that the metabolic rate during uphill running can be predicted by a model, which posits that (1 the metabolic cost of perpendicular bouncing remains the same as during level running, (2 the metabolic cost of running parallel to the running surface decreases with incline, (3 the delta efficiency of producing mechanical power to lift the COM vertically is constant, independent of incline and running velocity, and (4 the costs of leg and arm swing do not change with incline. To test this approach, we collected ground reaction force (GRF data for eight runners who ran thirty 30-second trials (velocity: 2.0–3.0 m/s; incline: 0–9°. We also measured the metabolic rates of eight different runners for 17, 7-minute trials (velocity: 2.0–3.0 m/s; incline: 0–8°. During uphill running, parallel braking GRF approached zero for the 9° incline trials. Thus, we modeled the metabolic cost of parallel running as exponentially decreasing with incline. With that assumption, best-fit parameters for the metabolic rate data indicate that the efficiency of producing mechanical power to lift the center of mass vertically was independent of incline and running velocity, with a value of ∼29