Acquisition Of Constraints Research Articles

New approach to constraining Cr-mineralization and forearc processes: U-Pb dating and geochemistry of titanites in chromitites of the Dun Mountain ophiolite belt (New Zealand)

Ophiolites provide important insights for understanding of subduction zones and forearc mantle-wedge geodynamics. Specifically, within the mantle section, podiform chromitites may record processes associated with development of highly depleted supra-subduction ophiolites, chromium mineralization and subsequent metasomatism. This study explores the first ever U-Pb isotope and trace-element data obtained from titanites in chromitites of the Dun Mountain ophiolite belt in New Zealand. Titanite is unusual in such geochemically depleted rocks and a low recovery rate attests to its rarity (ca. 190 grains from 100 kg of material from two chromitite samples). Results of U-Pb geochronology and geochemistry for the titanites constrain both the mid-Permian timing of chromitite crystallization (∼283 Ma) and later metasomatism (∼272 Ma). Older titanite grains are depleted in HFSE and have flat REE chondrite-normalized patterns reflecting a high-degree of partial melting in depths greater than the plagioclase stability field (>15 km). Younger titanites show enrichment in HFSE, depletion in LREE and negative Eu anomalies, revealing melt extraction at shallower depths (<15 km) that likely record refertilization of the mantle-wedge. Results highlight the potential of titanites in the acquisition of direct geochronological and geochemical constraints from rocks commonly devoid of minerals suitable for U-Pb dating.

Quantitative phase imaging with two in-line holograms.

Quantitative phase imaging (QPI) has emerged as a practical technique for acquiring structural information from phase objects. Digital holography can realize phase detection, but it is limited by a spatial bandwidth product or affected by the overlap of conjugate images. The phase retrieval algorithm serves as an effective tool for QPI dealing with intensity patterns. Traditional phase retrieval algorithms heavily rely on strong support constraints or high data redundancy to accurately reconstruct the sample image. However, in single-frame phase retrieval algorithms, the precise acquisition of support constraints is notably challenging. The multiple-measurement spends much time on data acquisition and is unsuitable for dynamic sample observation. In this paper, we propose a novel, to the best of our knowledge, quantitative phase imaging method that utilizes only two in-line holograms. We have developed a phase retrieval algorithm based on ptychography, which eliminates twin-image and separates illumination background. The proposed method achieves high data utilization efficiency and can be employed for dynamic imaging.

Obviating the mood, but mostly under control: Spanish heritage speakers’ acquisition of the binding constraints of desiderative complements

ABSTRACT Verbal morphology has been identified as a particularly vulnerable domain for adult heritage speakers (HSs) of Spanish, especially when it involves the selection of subjunctive mood. A minimal amount is known, however, about the potential effects of the variability associated with these forms on the acquisition of related epiphenomena, such as the anaphoric relations and binding constraints of complements that select subjunctive. The present investigation addresses this gap in the research by focusing on how HSs express and interpret subject co-referentiality and disjoint reference in desiderative constructions. Results from two experimental tasks (a Truth-Value judgment and a Sentence Completion task) revealed that participants’ Spanish proficiency was a significant predictor of their performance. In particular, more advanced HSs exhibited a higher likelihood of linking the presence of subjunctive to subject disjoint reference (a pattern observed among most Spanish controls) and a higher probability of using this form to express subject disjoint-reference in production. Furthermore, optionality in this domain was significantly linked to the degree to which HSs restructured the referential properties associated with subjunctive complements. Specifically, participants who exhibited lower rates of structural and morphological variability in connection to the expression of disjoint-reference also appeared to be more likely to assign this reading to the null subjects of subjunctive complements and reject the possibility of subject co-referentiality. These findings provide new evidence of how syntactic dependencies such as subject obviation and control are developed among heritage speakers of Spanish and explore the potential role of structural and morphological optionality in their (re)-configuration.

Using Computational Models to Test Syntactic Learnability

We studied the learnability of English filler-gap dependencies and the “island” constraints on them by assessing the generalizations made by autoregressive (incremental) language models that use deep learning to predict the next word given preceding context. Using factorial tests inspired by experimental psycholinguistics, we found that models acquire not only the basic contingency between fillers and gaps, but also the unboundedness and hierarchical constraints implicated in the dependency. We evaluated a model’s acquisition of island constraints by demonstrating that its expectation for a filler-gap contingency is attenuated within an island environment. Our results provide empirical evidence against the argument from the poverty of the stimulus for this particular structure.

A Fourier Approach to Kinematic Acquisition of Geometric Constraints of Planar Motion for Practical Mechanism Design

Abstract This paper studies the problem of geometric constraint acquisition from a given planar motion task using Fourier descriptor. In the previous work, we established a computational geometric framework for simultaneous type and dimensional synthesis of planar dyads by extracting line or circle constraints from a sequence of task poses. In cases where six or more poses are specified as the desired movement, the resulting optimal constraint may be nowhere in the accuracy neighborhood to be viewed as an approximate line or circle. The approach herein enhances the framework by exploiting Fourier transform to capture the feasible constraint of a continuous motion with a large set of poses. Theoretically, any arbitrary point trajectory on the task motion can be transformed to an array of harmonics and used as a constraint; on a practical level, only those with low number of harmonics could allow accurate realization by simple planar mechanisms suitable for real applications, e.g., four- and six-bar linkages, cams, and coupled serial chains. Therefore, the practical goal is to find the simple Fourier constraint defined with the least number of harmonics. Two examples of designing assistive mechanisms for upper- and lower-limb rehabilitation are provided in the end to illustrate the effectiveness of our approach.

A comparison of L2 and L1 speakers’ production of adverb positions in the Cardiff variety of Welsh

The grammaticality of adverb positions varies by language. Consequently, L2 and L1 speakers may differ from each other in their acquisition of adverb positions. Given that L2 Welsh speakers outnumber L1 Welsh speakers in Wales, differences in acquisition may change which adverb positions occur in contemporary Welsh. This study compares which adverb positions L2 and L1 speakers produce in the spoken data from Cardiff in the CorCenCC corpus (Knight et al., 2020) in order to identify any differences in acquisition. Comparisons of L2 and L1 English speakers find that L2 speakers consistently acquire novel adverb positions yet they frequently use ungrammatical adverb positions. They also do not acquire additional constraints on adverb positions. This study largely reinforces these findings. First, L2 Welsh speakers produce every adverb position that L1 speakers produce. Secondly, although the definiteness constraint that Borsley et al. (2009: 50) describe is not productive in the sample of Cardiff Welsh speakers, L1 speakers exhibit a heaviness constraint on V-Adv-O that L2 speakers do not. Therefore, L1 transfer neither inhibits the acquisition of adverb positions nor facilitates the acquisition of additional constraints. However, unlike L2 English speakers, L2 Welsh speakers do not produce ungrammatical adverb positions. This likely derives from the lack of transferable adverb positions between Welsh and English rather than a lack of transfer. Therefore, this sample of Cardiff Welsh reinforces the crosslinguistic consistency of L2 speakers’ acquisition of adverb positions. It also suggests that L2 Welsh speakers most likely diverge from L1 speakers in the contexts in which they use adverb positions rather than the adverb positions that they use.

The role of social factors in the acquisition of vernacular English: A variationist study with pedagogical implications

AbstractThe study reported here explores the role of various social factors in the L2 acquisition of vernacular variation. In so doing, it investigates acquisition of probabilistic constraints on the use of a globally available innovation, quotative be like, as a diagnostic linguistic variable. Drawing on data obtained from 37 individuals from three age cohorts all living in Mannheim, Germany, and applying the variationist method of evaluation, I show that German learners managed to acquire the variable grammar of quotative be like. I also test for a diverse set of sociolinguistic and sociopsychological variables by way of exploring their relative contribution to the process of acquiring structured variation by adult learners. The results of mixed‐effects modeling (Johnson 2009) show that acquisition of quotative be like is mediated by age, gender, and learners’ linguistic identity. I conclude that EFL (English as a Foreign Language) learners’ (implicit) knowledge about structured variation is an inherent component of their sociolinguistic competence, while drawing English teachers’ attention to the general importance of the issue concerning learners’ knowledge about structured variability.

Second Language Acquisition of Constraints on WH-Movement by L2 English Speakers: Evidence for Full-Access to Syntactic Features

This paper presents results from two experiments on the L2 acquisition of wh-features and relevant constraints (Superiority and Subjacency) by L1 Sinhala–L2 English speakers. Our results from a Truth Value Judgment Task and a Grammaticality Judgment Task with 31 English native controls and 38 Sinhala/English bilinguals show that the advanced adult L2 speakers of English we tested have successfully acquired the uninterpretable wh-Q feature and relevant movement constraints in English, despite the lack of overt wh-movement in L1-Sinhala. These results raise questions for Representational Deficit Accounts of second language acquisition and offer evidence that (i) uninterpretable syntactic features are not necessarily subject to an early critical period and (ii) uninterpretable features not instantiated in learners’ L1 can be available for L2 syntactic computation. We take our results as evidence for full access by L2 learners to syntactic properties that are not instantiated in their L1, but that remain accessible due to a cognitive capacity for language (i.e., knowledge of Universal Grammar) independently of the L1.

Ellipsoidal one-class constraint acquisition for quadratically constrained programming

We propose Ellipsoidal One-Class Constraint Acquisition (EOCCA), a fast and scalable algorithm for the acquisition of constraints for Mixed-Integer Quadratically Constrained Programming (MIQCP) models from data. EOCCA acquires a well-formed MIQCP model using solely the examples of the feasible solutions to this model. It combines x-means partitioning, standardization, and principal components analysis to preprocess the training set and then wraps the preprocessed data into several hyper-ellipsoids expressed using MIQCP constraints. These MIQCP constraints are projected back to the space of the original training set, and their further use does not require data preprocessing. Experimental evaluation shows that EOCCA scores better than a state-of-the-art algorithm in terms of fidelity of the acquired constraints to ground-truth constraints and achieves this in few orders of magnitude shorter time. We demonstrate the practical use case of EOCCA in a fully automated workflow of modeling and optimization of a rice farm using real-world data.

“¿Tú tienes una little pumpkin?” Mixed noun phrases in Spanish-English bilingual children and adults

Objectives: This study investigates the switching of a noun or a determiner in mixed noun phrases, such as “ una little pumpkin,” to test predictions from two theoretical frameworks, the Matrix Language Frame model (MLF) and the Minimalist Approach (MA) and examines whether there is a difference between child and adult code-switching (CS) patterns in order to understand children’s acquisition of grammatical patterns in general. Methodology: All tokens of mixed noun phrases (NPs) were extracted from three bilingual child corpora and one bilingual adult corpus. The finite verb (matrix language) of each utterance was also analyzed to test predictions. Data and analysis: Four hundred sixty-one mixed NPs were extracted from 15 Spanish-English bilingual children and 14 Spanish-English bilingual adults. Findings: Results support both the MLF and the MA since in more than 80% of our data, the language of the determiner matched the language of the finite verb morphology and the language with the most phi features. Originality: This is the first study to compare children’s and adults’ mixed NPs, testing predictions from the MLF and MA theories. It also provides new evidence for the acquisition of CS constraints in early bilingual language development. Implications: This study demonstrates that, like adults, children’s mixed NPs are subject to grammatical constraints. Some examples show that children produce mixed NPs immediately after hearing their caregivers produce the same NP, but in one language only. This supports the conclusion that children’s mixed NP patterns follow generalized constraints and are not item-based imitations of what they hear. Limitations: Future research should more carefully examine the CS patterns of caregivers and members of the community with whom children interact to decipher the role of input. This would help answer the question of how children acquire CS patterns.

Survey of alongside midwifery-led care in North Rhine-Westfalia, Germany.

Background Alongside midwifery-led care (AMC) was introduced in Germany in 2003. The aim of our study was to collect data about the utilization of AMC within North Rhine-Westfalia (NRW), Germany's most populous state, and to collect information regarding the approach used for implementation of AMC and providers' experiences in day-to-day work. Methods Quantitative data were collected by questionnaire, telephone interview and comparative analysis of documents created for use in AMC. Qualitative data were compiled by questionnaire and workshop. Results Seven obstetric departments offer AMC in NRW. On average, 3.4% of women gave birth in these AMC units, corresponding to 0.3% of all births in NRW. For the establishment of AMC, institutional, organizational, professional and formal arrangements were undertaken. An eligibility and transfer checklist was agreed upon between midwives and obstetricians. Both professions were faced with skepticism. Daily work in AMC resulted in improved teamwork between the two professions and increased job satisfaction for midwives. Acquisition of manual skills and time constraints were the major challenges. Conclusion The low utilization of AMC is not due to the concept of care itself or difficulties with its implementation, nor to a lack of eligible women. Reasons may be insufficient awareness about AMC or a lack of interest in this type of care.

Plotting individual learning trajectories in the acquisition of L2 prosodic constraints

Plotting individual learning trajectories in the acquisition of L2 prosodic constraints

Going global and sounding local

AbstractWe chart the incursion of quotativebe likeinto Dublin English, drawing comparisons with similar developments in urban Canadian English as well as with diachronic benchmarks representing vernacular Irish English. Quantitative analysis reveals thatbe likeis the lead variant in the quotative system used by young Dubliners and is advancing along a similar, though not identical, cline of grammaticalization to that found in urban Canadian English. We use the resultant information about the Dublin English quotative system as a baseline to assess the extent to which this system has been acquired by Polish-born L2 speakers of English differentiated in terms of target language proficiency. Comparison of the L2 quotative system with the L1 Dublin English benchmark reveals that not all L1 usage constraints are faithfully replicated by L2 speakers, indicating that the acquisition of the relevant constraints is incomplete, even in the case of advanced learners.

The acquisition of L3 variation among early bilinguals

Abstract The present study investigates whether prior experience with formal study of an L2 influences L3 Korean learners’ Type 1 variation (i.e., use of obligatory forms) and Type 2 variation (i.e., variation between alternative acceptable variants). The patterns of variation in Korean argument realization of early bilingual learners (English-Chinese/Malay/Indonesian/Tamil) of L3 Korean were assessed in light of the distribution of variants present in classroom input, learners’ prior L2 learning experience and home language background, argument animacy and number, and familiarity of verb structure type. Our findings demonstrate that prior experience with a typologically-similar L2 facilitates acquisition of grammatical patterns as well as acquisition of native-like patterns of variation between grammatical forms that are constrained by a range of internal linguistic factors. Any L2 experience, regardless of typological proximity, is found to facilitate acquisition of internal linguistic constraints, but not acquisition of grammatical patterns.

Acquisition of Contraction Constraint by Japanese Learners of English

Second language (L2) acquisition research has explored the acquisition of various syntactic constraints by L2 learners, one of which is wanna contraction. However, there is still a very limited body of research regarding the acquisition of wanna contraction, both in first language (L1) and L2. The purpose of the study is to examine adult L2 learners’ knowledge of wanna contraction by using a grammaticality judgment task. Ninety-three Japanese learners of English took the grammaticality judgment task which consisted of 24 experimental items and 24 fillers, with a context provided. The experimental stimuli consisted of six conditions: Object extraction (e.g., Who do you want to/wanna advise?), subject extraction (e.g., Who do you want to/*wanna advise Mary?), and no extraction (e.g., Do you want to/wanna advise Mary?), all of which were presented with and without contraction. Subject extraction with contraction was the only ungrammatical condition. The participants were divided into three groups according to their English proficiency as measured by the cloze test: High level (JPN-H), intermediate level (JPN-I), and low level (JPN-L). The same grammaticality judgment task was also given to 41 native speakers of English in order to collect the baseline data. The results showed a proportional increase of learners who were correctly differentiating the contraction patterns and the decrease of those who were overgeneralizing the patterns over the three proficiency groups. This suggests a developmental pattern among the L2 learners with respect to the contraction constraint.

Contextual variability and exemplar strength in phonotactic learning.

Phonotactics-constraints on the position and combination of speech sounds within syllables-are subject to statistical differences that gradiently affect speaker and listener behavior (e.g., Vitevitch & Luce, 1999). What statistical properties drive the acquisition of such constraints? Because they are naturally highly correlated, previous work has been unable to dissociate the contribution of 2 properties: contextual variability (the number of unique phonological contexts in which a phonotactic pattern appears) and exemplar strength (the overall number of times the pattern appears). Using an artificial language learning paradigm, 3 experiments disentangled the effects of variability and strength, indexed by type and token frequency, respectively, on the learning of gradient phonotactics. When the 2 factors were decorrelated (Experiment 2), participants showed greater generalization of patterns advantaged for contextual variability, but not those advantaged for exemplar strength. When the 2 factors were anticorrelated (Experiment 3), participants preferred patterns advantaged in contextual variability, even though they were disadvantaged for exemplar strength. These results suggest that contextual variability is the key force driving phonotactic learning, as it allows learners to home in on the invariant features of the input. (PsycINFO Database Record

Lack of knowledge and availability of diagnostic equipment could hinder the diagnosis of sarcopenia and its management.

ObjectivesSarcopenia is an emerging clinical challenge in an ageing population and is associated with serious negative health outcomes. This study aimed to assess the current state of the art regarding the knowledge about the concept of sarcopenia and practice of the diagnostic strategy and management of sarcopenia in a cohort of Dutch healthcare professionals (physicians, physiotherapists, dietitians and others) attending a lecture cycle on sarcopenia.Material and methodsThis longitudinal study included Dutch healthcare professionals (n = 223) who were asked to complete a questionnaire before, directly after and five months after (n = 80) attending a lecture cycle on the pathophysiology of sarcopenia, diagnostic strategy and management of sarcopenia, i.e. interventions and collaboration.ResultsBefore attendance, 69.7% of healthcare professionals stated to know the concept of sarcopenia, 21.4% indicated to know how to diagnose sarcopenia and 82.6% had treated patients with suspected sarcopenia. 47.5% used their clinical view as diagnostic strategy. Handgrip strength was the most frequently used objective diagnostic measure (33.9%). Five months after attendance, reported use of diagnostic tests was increased, i.e. handgrip strength up to 67.4%, gait speed up to 72.1% and muscle mass up to 20.9%. Bottlenecks during implementation of the diagnostic strategy were experienced by 67.1%; lack of awareness among other healthcare professionals, acquisition of equipment and time constraints to perform the diagnostic measures were reported most often. Before attendance, 36.4% stated not to consult a physiotherapists or exercise therapists (PT/ET) or dietitian for sarcopenia interventions, 10.5% consulted a PT/ET, 32.7% a dietitian and 20.5% both a PT/ET and dietitian. Five months after attendance, these percentages were 28.3%, 21.7%, 30.0% and 20.0% respectively.ConclusionThe concept of sarcopenia is familiar to most Dutch healthcare professionals but application in practice is hampered, mostly by lack of knowledge, availability of equipment, time constraints and lack of collaboration.

A Line Geometric Approach to Kinematic Acquisition of Geometric Constraints of Planar Motion

This paper examines the problem of geometric constraints acquisition of planar motion through a line-geometric approach. In previous work, we have investigated the problem of identifying point-geometric constraints associated with a motion task which is given in a parametric or discrete form. In this paper, we seek to extend the point-centric approach to the line-centric approach. The extracted geometric constraints can be used directly for determining the type and dimensions of a physical device such as mechanical linkage that generates this constrained motion task.

Negative knowledge from positive evidence

Why can’t we say the asleep cat ? There is a class of adjectives in English, all of which start with a schwa (e.g. afraid, alone, asleep, away , etc.), that cannot be used attributively in a prenominal position. A frequently invoked strategy for the acquisition of such negative constraints in language is to use indirect negative evidence. For instance, if the learner consistently observes paraphrases such as the cat that is asleep , then the conspicuous absence of the asleep cat may be a clue for its ungrammaticality (Boyd &amp; Goldberg 2011). This article provides formal and quantitative evidence from child-directed English data to show that such learning strategies are untenable. However, the child can rely on positive data to establish the distributional similarities between this apparently idiosyncratic class of adjectives and locative particles (e.g. here, over, out , etc.) and prepositional phrases. With the use of an independently motivated principle of generalization (Yang 2005), the ungrammaticality of attributive usage can be effectively extended to the adjectives in question.

Non-native Acquisition of Phonotactic Constraints: A Study of English Pronunciation by Korean Learners

Non-native Acquisition of Phonotactic Constraints: A Study of English Pronunciation by Korean Learners