A usage-based analysis of four constructions in Spanish, each with a different verb meaning ‘become’ used with an animate subject and an adjective, provides evidence for exemplar representations of constructions, with analogy to these representations accounting for productive use. We analyze 423 tokens from spoken and written corpora, which we take to represent a subset of a speaker's experience with these constructions. The analysis, based on token frequency and semantic similarity, leads to the organization of tokens with two of the verbs into dense clusters of semantically related adjectives centered on a high-frequency exemplar. The other two verbs are used with more diverse sets of adjectives. We supplement the initial analysis with an experiment in which speakers were asked to rate the semantic similarity of pairs of adjectives. When subjected to multidimensional scaling, the results of the experiment support the initial analysis. We argue that novel instances of verb + adjective sequences are based on analogies to previous experience and not on rules that refer to abstract features. In a second experiment, speakers judged the acceptability of sentences taken from the corpora; the results showed that high-frequency expressions and expressions semantically similar to the high-frequency ones lead to an expression being judged more acceptable. Overall the results support exemplar representations, which are heavily based on usage experience.

Controlling oxygen concentration at a microscale level can benefit experimental investigations involving oxidative stress, ischemia, and reactive oxygen species (ROS) mediated cellular pathways. Here, we report the application of microfluidic gradient generation in an open-well culture model, in which a gradient of gas is delivered via diffusion through a gas permeable substrate that separates cells from the gas microchannels below. By using diffusion to localize oxygen delivery, microgradients of oxygen concentrations can be rapidly and controllably applied without exposing cells to mechanical stresses or reducing culture volumes inside microfluidic culture chambers. Furthermore, we demonstrate the modulation of intracellular ROS levels in Madin–Darby Canine Kidney (MDCK) cells by applying these oxygen microgradients. Increases in ROS levels consistent with both oxidative stress and hypoxic exposures were observed in MDCK cells. The measured ROS increases were comparable to 100 µM hydrogen peroxide exposure in a control comparison, which is within the range of standard ROS induction methods. Incubation with 200 µM vitamin C was able to demodulate the ROS response at both hypoxic and hyperoxic exposures. By providing microfluidic controlled gradients, constant ROS exposure, and a shear-free open well design, the devices introduced here greatly improve upon standard oxygen-based culturing methods.

Intensity differences were used to measure the degree of lenition of the voiced approximants in various contexts in order to contrast them with their stop variants [b, d, g], and in order to investigate the contexts in which they are traditionally thought to appear. 3,011 instances were taken from telephone conversations of eight native Spanish speakers from seven countries. The influence of phonetic context (post-pausal, post-nasal, post-lateral, etc.), stress, word frequency, appearance in a suffix (e.g., -ado, -aba) was determined using multiple regression. In line with traditional analyses, the results show that the voiced approximants are most lenited intervocalically and least lenited after a pause. However, post-nasal and post-lateral instances fall between these extremes. In addition, /β/, , and /γ/ are also more stop-like when following [s] or [h]. Traditional analyses do not factor in the influence of stress, word frequency, word boundaries, or appearance in a suffix, yet these emerge as significant predictors. Although the distribution of the variants of these three approximants is generally thought to be due to a unitary rule, significant differences between the three suggest otherwise. When followed by a stressed syllable, /β/ and exhibit more constriction when compared to /γ/, while all three phones are less lenited when they fall between two stressed syllables. /β/ and are also more constricted when they appear intervocalically in word-initial position when compared to word-internal intervocalic tokens, while the same is not true for /γ/. Contra traditional descriptions, is no less lenited than /β/ or /γ/ following a lateral. Instances of are also more lenited when they appear in high frequency words and less lenited in low frequency words. On the other hand, frequency is not a factor for /β/ and /γ/.

Oxygen is a key modulator of many cellular pathways, but current devices permitting in vitro oxygen modulation fail to meet the needs of biomedical research. A microfabricated insert for multiwell plates has been developed to more effectively control the temporal and spatial oxygen concentration to better model physiological phenomena found in vivo. The platform consists of a polydimethylsiloxane insert that nests into a standard multiwell plate and serves as a passive microfluidic gas network with a gas-permeable membrane aimed to modulate oxygen delivery to adherent cells. Equilibration time is on the order of minutes and a wide variety of oxygen profiles can be attained based on the device design, such as the cyclic profile achieved in this study, and even oxygen gradients to mimic those found in vivo. The proper biological consequences of the device's oxygen delivery were confirmed in cellular models via a proliferation assay and western analysis of the upregulation of hypoxia inducible transcription factor-1α. These experiments serve as a demonstration for the platform as a viable tool to increase experimental throughput and permit novel experimental possibilities in any biomedical research lab.