Contrast implementation affects phonetic variability: A case study of Hindi and English stops

There is a large body of work in phonetics and phonology demonstrating sources and structure of acoustic variability, showing that variability in speech production is not random. This paper examines the question of how variability itself varies across languages and speakers, arguing that differences in extent of variability are also systematic. A classic hypothesis from Dispersion Theory (Lindblom, 1986) posits a relationship between extent of variability and phoneme inventory size, but this has been shown to be inadequate for predicting differences in phonetic variability. I propose an alternative hypothesis, Contrast-Dependent Variation, which considers cue weight of individual phonetic dimensions rather than size of phonemic inventories. This is applied to a case study of Hindi and American English stops and correctly predicts more variability in English stop closure voicing relative to Hindi, but similar amounts of lag time variability in both languages. In addition to these group-level between- language differences, the results demonstrate how patterns of individual speaker differences are language-specific and conditioned by differences in phonological contrast implementation.

Constraint summation in phonological theory

The classical constraints used in phonological theory apply to a single candidate at a time. Yet, some proposals in the phonological literature have enriched the classical constraint toolkit with constraints that instead apply to multiple candidates simultaneously. For instance, Dispersion Theory (Flemming 2002, 2004, 2008) adopts distinctiveness constraints that penalize pairs of surface forms which are not sufficiently dispersed. Also, some approaches to paradigm uniformity effects (Kenstowicz 1997; McCarthy 2005) adopt Optimal Paradigm faithfulness constraints that penalize pairs of stems in a paradigm which are not sufficiently similar. As a consequence, these approaches need to “lift” the classical constraints from a single candidate to multiple candidates by summing constraint violations across multiple candidates.Is this assumption of constraint summation typologically innocuous? Or do the classical constraints make different typological predictions when they are summed, independently of the presence of distinctiveness or optimal paradigm faithfulness constraints? The answer depends on the underlying model of constraint optimization, namely on how the profiles of constraint violations are ordered to determine the smallest one. Extending an independent result by Prince (2015), this paper characterizes those orderings for which the assumption of constraint summation is typologically innocuous. As a corollary, the typological innocuousness of constraint summation is established within both Optimality Theory and Harmonic Grammar.

Basic Geometric Dispersion Theory of Decision Making Under Risk: Asymmetric Risk Relativity, New Predictions of Empirical Behaviors, and Risk Triad

Many studies have spotlighted significant applications of expected utility theory (EUT), cumulative prospect theory (CPT), and mean-variance in assessing risks. We illustrate that these models and their extensions are unable to predict risk behaviors accurately in out-of-sample empirical studies. EUT uses a nonlinear value (utility) function of consequences but is linear in probabilities, which has been criticized as its primary weakness. Although mean-variance is nonlinear in probabilities, it is symmetric, contradicts first-order stochastic dominance, and uses the same standard deviation for both risk aversion and risk proneness. In this paper, we explore a special case of geometric dispersion theory (GDT) that is simultaneously nonlinear in both consequences and probabilities. It complies with first-order stochastic dominance and is asymmetric to represent the mixed risk-averse and risk-prone behaviors of the decision makers. GDT is a triad model that uses expected value, risk-averse dispersion, and risk-prone dispersion. GDT uses only two parameters, z and zX; these constants remain the same regardless of the scale of risk problem. We compare GDT to several other risk dispersion models that are based on EUT and/or mean-variance, and identify verified risk paradoxes that contradict EUT, CPT, and mean-variance but are easily explainable by GDT. We demonstrate that GDT predicts out-of-sample empirical risk behaviors far more accurately than EUT, CPT, mean-variance, and other risk dispersion models. We also discuss the underlying assumptions, meanings, and perspectives of GDT and how it reflects risk relativity and risk triad. This paper covers basic GDT, which is a special case of general GDT of Malakooti [Malakooti (2020) Geometric dispersion theory of decision making under risk: Generalizing EUT, RDEU, & CPT with out-of-sample empirical studies. Working paper, Case Western Reserve University, Cleveland.].

Sales and Markup Dispersion: Theory and Empirics

We characterize the relationship between the distributions of two variables linked by a structural model. We then show that, in models of heterogeneous firms in monopolistic competition, this relationship implies a new demand function that we call “CREMR” (Constant Revenue Elasticity of Marginal Revenue). This demand function is the only one that is consistent with productivity and sales distributions having the same form (whether Pareto, lognormal, or Fréchet) in the cross section, and it is necessary and sufficient for Gibrat's Law to hold over time. Among the applications we consider, we use our methodology to characterize misallocation across firms; we derive the distribution of markups implied by any assumptions on demand and productivity; and we show empirically that CREMR‐based markup distributions provide an excellent parsimonious fit to Indian firm‐level data, which in turn allows us to calculate the proportion of firms that are of suboptimal size in the market equilibrium.

Diffusion and steady state distributions of flexible chemotactic enzymes

Many experiments in recent years have reported that, when exposed to their corresponding substrate, catalytic enzymes undergo enhanced diffusion as well as chemotaxis (biased motion in the direction of a substrate gradient). Among other possible mechanisms, in a number of recent works we have explored several passive mechanisms for enhanced diffusion and chemotaxis, in the sense that they require only binding and unbinding of the enzyme to the substrate rather than the catalytic reaction itself. These mechanisms rely on conformational changes of the enzyme due to binding, as well as on phoresis due to non-contact interactions between enzyme and substrate. Here, after reviewing and generalizing our previous findings, we extend them in two different ways. In the case of enhanced diffusion, we show that an exact result for the long-time diffusion coefficient of the enzyme can be obtained using generalized Taylor dispersion theory, which results in much simpler and transparent analytical expressions for the diffusion enhancement. In the case of chemotaxis, we show that the competition between phoresis and binding-induced changes in diffusion results in non-trivial steady state distributions for the enzyme, which can either accumulate in or be depleted from regions with a specific substrate concentration.

Phonetic realisations of Madurese vowels and their implications for the Madurese vowel system

It has been suggested that Madurese has eight surface vowels [a, ɛ, ə, ɔ, ɤ, i, ɨ, u], but there have been disagreements with regard to the number of its vowel phonemes. The disagreements arise partly because some scholars base their analyses of Madurese vowels on phonetic grounds while others base them on certain phonological analyses. Besides, some researchers do not consider native versus non-native Madurese words in their analyses. The paper addresses these problems by incorporating both phonetic and phonological analyses in order to provide a better description of Madurese vowels. To achieve this, we investigated the acoustic realisations of the eight surface vowels by looking at the first and second formant frequencies (F1 and F2) of the high and non-high vowel pairs (i ~ ɛ, ɨ ~ ə, ɤ ~ a, u ~ ɔ). Fifteen speakers of Madurese were recorded reading Madurese words put in a carrier phrase. All segmentations were done employing Praat, and F1 and F2 values were extracted using a Praat script. The data were assessed with a linear mixed-effects model accounting for variation due to both random and fixed factors. The results showed that all high and non-high vowel pairs significantly differed in their F1 values. However, the results for F2 values showed variations; only the pair [ɨ ~ ə] showed a significant difference at vowel onset and at vowel midpoint the pairs [i ~ ɛ] and [ɨ ~ ə] were significantly different. Furthermore, we also looked at the vowels [ɤ] and [ɨ] as well as [ɤ] and [ə] to see if they differed in their F1 and F2 values. Our results confirmed that at both vowel onset and midpoint, they were significantly different. The results were discussed employing phonological analysis and vowel dispersion theory. The result of the analyses suggests that Madurese should be best described as a language with a four-vowel system and further offers a solution to the disagreements on the number of vowel phonemes in Madurese