Refine
Year of publication
Document Type
- Article (16101)
- Part of Periodical (2822)
- Working Paper (2358)
- Preprint (2256)
- Doctoral Thesis (2069)
- Book (1736)
- Conference Proceeding (1196)
- Part of a Book (1071)
- Report (471)
- Review (165)
Language
- English (30440) (remove)
Keywords
- taxonomy (749)
- new species (449)
- morphology (178)
- Deutschland (142)
- Syntax (126)
- Englisch (120)
- distribution (117)
- biodiversity (103)
- inflammation (100)
- Deutsch (98)
Institute
- Medizin (5426)
- Physik (4103)
- Wirtschaftswissenschaften (1928)
- Frankfurt Institute for Advanced Studies (FIAS) (1877)
- Biowissenschaften (1571)
- Informatik (1515)
- Center for Financial Studies (CFS) (1499)
- Biochemie und Chemie (1093)
- Sustainable Architecture for Finance in Europe (SAFE) (1077)
- House of Finance (HoF) (714)
When speech is too fast, the tracking of the acoustic signal along the auditory pathway deteriorates, leading to suboptimal speech segmentation and decoding of speech information. Thus, speech comprehension is limited by the temporal constraints of the auditory system. Here we ask whether individual differences in auditory-motor coupling strength in part shape these temporal constraints. In two behavioral experiments, we characterize individual differences in the comprehension of naturalistic speech as function of the individual synchronization between the auditory and motor systems and the preferred frequencies of the systems. Obviously, speech comprehension declined at higher speech rates. Importantly, however, both higher auditory-motor synchronization and higher spontaneous speech motor production rates were predictive of better speech-comprehension performance. Furthermore, performance increased with higher working memory capacity (Digit Span) and higher linguistic, model-based sentence predictability – particularly so at higher speech rates and for individuals with high auditory-motor synchronization. These findings support the notion of an individual preferred auditory– motor regime that allows for optimal speech processing. The data provide evidence for a model that assigns a central role to motor-system-dependent individual flexibility in continuous speech comprehension.
When speech is too fast, the tracking of the acoustic signal along the auditory pathway deteriorates, leading to suboptimal speech segmentation and decoding of speech information. Thus, speech comprehension is limited by the temporal constraints of the auditory system. Here we ask whether individual differences in auditory-motor coupling strength in part shape these temporal constraints. In two behavioural experiments, we characterize individual differences in the comprehension of naturalistic speech as function of the individual synchronization between the auditory and motor systems and the preferred frequencies of the systems. Obviously, speech comprehension declined at higher speech rates. Importantly, however, both higher auditory-motor synchronization and higher spontaneous speech motor production rates were predictive of better speech-comprehension performance. Furthermore, performance increased with higher working memory capacity (digit span) and higher linguistic, model-based sentence predictability—particularly so at higher speech rates and for individuals with high auditory-motor synchronization. The data provide evidence for a model of speech comprehension in which individual flexibility of not only the motor system but also auditory-motor synchronization may play a modulatory role.
We use observations of total particle number concentration at 36 worldwide sites and a global aerosol model to quantify the primary and secondary sources of particle number. We show that emissions of primary particles can reasonably reproduce the spatial pattern of observed condensation nuclei (CN) (R2=0.51) but fail to explain the observed seasonal cycle at many sites (R2=0.1). The modeled CN concentration in the free troposphere is biased low (normalised mean bias, NMB=−88%) unless a secondary source of particles is included, for example from binary homogeneous nucleation of sulfuric acid and water (NMB=−25%). Simulated CN concentrations in the continental boundary layer (BL) are also biased low (NMB=−74%) unless the number emission of anthropogenic primary particles is increased or an empirical BL particle formation mechanism based on sulfuric acid is used. We find that the seasonal CN cycle observed at continental BL sites is better simulated by including a BL particle formation mechanism (R2=0.3) than by increasing the number emission from primary anthropogenic sources (R2=0.18). Using sensitivity tests we derive optimum rate coefficients for this nucleation mechanism, which agree with values derived from detailed case studies at individual sites.
We synthesised observations of total particle number (CN) concentration from 36 sites around the world. We found that annual mean CN concentrations are typically 300–2000 cm -3 in the marine boundary layer and free troposphere (FT) and 1000–10 000 cm -3 in the continental boundary layer (BL). Many sites exhibit pronounced seasonality with summer time concentrations a factor of 2–10 greater than wintertime concentrations. We used these CN observations to evaluate primary and secondary sources of particle number in a global aerosol microphysics model. We found that emissions of primary particles can reasonably reproduce the spatial pattern of observed CN concentration (R2=0.46) but fail to explain the observed seasonal cycle (R2=0.1). The modeled CN concentration in the FT was biased low (normalised mean bias, NMB=& -88%) unless a secondary source of particles was included, for example from binary homogeneous nucleation of sulfuric acid and water (NMB= -25%). Simulated CN concentrations in the continental BL were also biased low (NMB= -74%) unless the number emission of anthropogenic primary particles was increased or a mechanism that results in particle formation in the BL was included. We ran a number of simulations where we included an empirical BL nucleation mechanism either using the activation-type mechanism (nucleation rate, J, proportional to gas-phase sulfuric acid concentration to the power one) or kinetic-type mechanism (J proportional to sulfuric acid to the power two) with a range of nucleation coefficients. We found that the seasonal CN cycle observed at continental BL sites was better simulated by BL particle formation (R2=0.3) than by increasing the number emission from primary anthropogenic sources (R2=0.18). The nucleation constants that resulted in best overall match between model and observed CN concentrations were consistent with values derived in previous studies from detailed case studies at individual sites. In our model, kinetic and activation-type nucleation parameterizations gave similar agreement with observed monthly mean CN concentrations.
A number of recent studies have concluded that consumer spending patterns over the month are closely linked to the timing of income receipt. This correlation is interpreted as evidence of hyperbolic discounting. I re-examine patterns of spending in the diary sample of the U.S. Consumer Expenditure Survey, incorporating information on the timing of the main consumption commitment for most households - their monthly rent or mortgage payment. I find that non-durable and food spending increase with 30-48% on the day housing payments are made, with smaller increases in the days after. Moreover, households with weekly, biweekly and monthly income streams but the same timing of rent/mortgage payments have very similar consumption patterns. Exploiting variation in income, I find that households with extra liquidity decrease non-durable spending around housing payments, especially those households with a large budget share of housing.
Magnitude processing is one of the most central cognitive mechanisms that underlie persistent mathematics difficulties. No consensus has yet been reached about whether these difficulties can be predominantly attributed to deficits in symbolic or nonsymbolic magnitude processing. To investigate this issue, we assessed symbolic and nonsymbolic magnitude representations in children with low or typical achievement in school mathematics. Response latencies and the distance effect were comparable between groups in both symbolic and nonsymbolic tasks. The results indicated that both typical and low achievers were able to access magnitude representation via symbolic and nonsymbolic processing. However, low achievers presented higher error rates than typical achievers, especially in the nonsymbolic task. Furthermore, measures of nonsymbolic magnitude explained individual differences in school mathematics better than measures of symbolic magnitude when considering all of the children together. When examining the groups separately, symbolic magnitude representation explained differences in school mathematics in low achievers but not in typical achievers. These results suggest that symbolic magnitude is more relevant to solving arithmetic problems when mathematics achievement is particularly low. In contrast, individual differences in nonsymbolic processing appear to be related to mathematics achievement in a more general manner.
This paper investigates how US and European equity markets affected the US dollar-euro rate from the introduction of the euro through April 2001. More detailed the following questions are raised: First, do movements in the stock market help to explain movements in the exchange rate? Second, how large is the impact of stock market returns on the exchange rate? And third, does the exchange rate respond differently to different equity markets? The investigation was carried out using daily data within a vector-autoregression model (VAR). Surprisingly, positive returns on US equities as well as on European stock markets had a negative impact on the US dollar-euro rate. Quantitatively, the US dollar-euro rate seems to be more influenced by European stock markets compared to US stock markets. Further, there is evidence for a somewhat weaker impact of technology stock indices on the US dollar-euro rate compared with broader market indices. Finally, the long-term interest rate differential seems to contain more information about exchange rate movements than the short-term interest rate differential. This Version: August, 2001. Klassifikation: C32, F31
Explanations and "engineering solutions"? Aspects of the relation between Minimalism and HPSG
(2017)
It is not simple to compare Minimalism and HPSG, but it is possible to identify a variety of differences, some not so important but others of considerable importance. Two of the latter are: (1) the fact that Minimalism is a very lexically-based approach whereas HPSG is more syntactically-based, and (2) the fact that Minimalism uses Internal Merge in the analysis of unbounded dependencies whereas HPSG employs the SLASH feature. In both cases the HPSG approach seems to offer a better account of the facts. Thus, in two important respects it seems preferable to Minimalism.
Expletives as features
(2000)
Expletives have always been a central topic of theoretical debate and subject to different analyses within the different stages of the Principles and Parameter theory (see Chomsky 1981, 1986, 1995; Lasnik 1992, 1995; Frampton and Gutman 1997; among others). However, most analyses center on the question how to explain the behavior of expletives in A-chains (such as there in English or Þad in Icelandic). No account relates wh-expletives (as one finds them in so-called partial wh-movement constructions in languages such as Hungarian, Romani, and German) to expletives in Achains. In this paper, I argue that the framework of the Minimalist Program opens up the possibility of accounting for expletive-associate relations in A-/A'-chains in a unified manner. The main idea of the unitary analysis is that an expletive is an overtly realized feature bundle that is (sub)extracted from its associate DP. There in an expletive-associate chain is a moved D-feature which orginates inside the associate DP. Similarily, in A'-chains, the whexpletive originates as a focus-/wh-feature in the wh-phrase with which it is associated. This analysis provides evidence for the feature-checking theory in Chomsky (1995). The paper is organized as follows. Section 2 contains the discussion of expletive there. In section 3 I suggest an analysis for whexpletives, and I also explore whether this analysis can be extended to relations between X°-categories such as auxiliary and participle complexes.
Modern computational molecular quantum chemical studies, such as the present one, typically employ a wide range of theoretical techniques. The latter are often rather complicated and one should not generally expect that an experimental scientist in the area of physical chemistry, a potential reader of this work, should be familiar with all these techniques. To simplify the reading of the Thesis and to make it self-sufficient, it is supplied with an overview of the employed theoretical methodologies (Chapter 1). The overview explains basic quantum-chemical terminology referred to throughout the Thesis, introduces theoretical foundations of the methods and outlines their properties and limitations. In Part 1.1 of Chapter 1, methods for the solution of the molecular Schrödinger equation are introduced, while in the subsequent Parts 1.2 and 1.3 methods for the solution of the electronic Schrödinger equation are presented to find the ground and excited states, respectively. Part 1.4 is dedicated to basis-set effects which are omnipresent in electronic-structure calculations. It contains a number of unusual insights and concepts proposed by the author and, thus, may be insightful also to experts in quantum chemistry.
In Chapter 2, the phenomenon of acetone-water proton exchange catalyzed by tubular as well as amorphous aggregates of calix[4]hydroquinone (CHQ) macromolecules, which has been observed previously in NMR experiments (Ref. D1D), is investigated by means of correlated quantum-chemical methods. The first part of the study (Section 2.3-2.7) considers concerted proton transfer, assisted by several initially neutral OH-groups in the hydrogen-bonded networks of CHQ aggregates. The second part of the study (Section 2.8-2.13) is dedicated to a second mechanism of proton exchange: step-wise proton transfer via formation of ionic intermediates resulting from CHQ pre-dissociation. CHQ application-specific as well as general conclusions, relevant to the main topic of the Thesis (i.e. influence of specific microsolvation on the considered proton transfer processes), are presented in Section 2.14.
The phenomenon of dual fluorescence observed in clusters of methyl 4-N,N-dimethylaminobenzoate ester (DMABME) and two water molecules in the gas phase, is studied in Chapter 3. Experimentally, the dual fluorescence was detected in experiments combining optical and ground-state ion-depletion infrared spectroscopies in ultracold molecular beams (Ref. D2D). In Section 3.3, calculated ground-state infrared spectra are presented that allow to identify the structures of those isomers, which are present in the gas-phase, as well as the structure of the isomer responsible for dual fluorescence. To further understand the reaction mechanism of dual fluorescence, excited-state potential energy surfaces of the identified isomers were computed along the relevant twisted intermolecular charge-transfer formation coordinate and the mechanism of energy dissipation in these complexes was investigated (Section 3.4-3.5) (Ref. D3D). A brief summary of the main results of this chapter and conclusions are given in Section 3.6. Finally, in Section 3.7 a complementary benchmark study of the quality of ground-state potential energy surfaces of prototypical hydrogen-bonded systems (ammonia-water and formic acid-water dimers) obtained at the level of BSSE-corrected MP2 combined with moderate basis sets, has been conducted. The quality of potential energy surfaces was tested with respect to basis-set size, level of electron correlation and anharmonicity effects and the applied methodology to identify the IR spectrum of hydrated DMABME complexes (Section 3.3) has been found to be sufficient to uniquely assign the IR spectra.