Search

This study investigates child heritage speakers’ Spanish direct objects. A task designed to elicit direct objects was completed in Spanish and English by 40 child heritage speakers of Spanish in the U.S., and in Spanish by 24 monolingual children in Mexico. Both participant groups varied their direct object forms, following the same ranking: clitics>lexical NPs>omission>doubling. Animate referents promoted clitics; inanimate referents promoted lexical NPs. Among the heritage speakers, more Spanish experience and Spanish lexical proficiency predicted more clitic use (less omission and lexical NP use). We also argue that the child heritage speakers’ production of strong pronouns, more lexical NPs, and masculine clitic lo with inanimate feminine referents suggest English influence. The study underscores the importance of examining structured variation, which revealed both similarities and differences between heritage and monolingual speakers.

Child language acquisition research has provided ample evidence of lexical frequency effects. This corpus-based analysis introduces a novel frequency measure shown to significantly constrain adult language variation, but heretofore unexplored in child language acquisition research. Among adults, frequent occurrence of a form in a particular discourse context that conditions usage accumulates in memory over time and shapes the lexical representation of that form. This study contributes to the body of research on frequency effects in child language acquisition by testing whether such cumulative conditioning effects are also found among children, and, if so, at what age such effects appear. Specifically, the study investigates the influence of a distributional frequency measure (each verb form’s likelihood of use in a switch vs same-reference discourse context) on variable subject personal pronoun (SPP) expression ( N = 2227) in Spanish (e.g. yo voy ~ voy, both meaning ‘I go’) in the speech of 65 monolingual children in two age cohorts. Results reveal sensitivity to the contextual conditioning of discourse continuity (switch reference) among both the younger (6- and 7-year-olds) and older (8- and 9-year-olds) children in support of previous research. In addition, each verb’s likelihood of use in a switch-reference context significantly predicted the SPP use among the older children, but not the younger ones, suggesting that the cumulative effect of a probabilistic pattern takes time to emerge during childhood. The lexically specific accumulation in memory of contextual conditioning effects supports exemplar models of child language acquisition: each instance of use in discourse contributes to the lexical representation of that form and, over time, plays a role in the creation of morphosyntactic patterns during language development.

This article presents a developmental pathway for the acquisition of morphosyntactic variation. Although there is abundant evidence that morphosyntactic variation is pervasive among adults, much le...

This article reviews Bilingualism in the community. Code-switching and grammars in contact 9781108235259

Scholars have argued that restricted language input slows language acquisition, but the pathway of development may remain the same. The current study investigated the influence of amount of Spanish input on Spanish demonstrative usage among 19 U.S. child heritage speakers, ages 3;4–8;7. Demonstratives are among the first grammatical features to emerge in children’s language, but we know little about their acquisition by heritage speakers. Previous research shows that monolingual Spanish-speaking children rely heavily on este/esta ‘this’ andonly later learn to vary between demonstrative forms, using este/esta primarily for proximal referents and ese/esa ‘that’ for distal referents. As such, we hypothesized that child heritage speakers who experience restricted Spanish input would rely on este/esta for a prolonged period of time. 586 demonstratives were elicited during a puzzle completion task and were coded for referent location (proximal, distal). Contrary to our hypothesis, less Spanish spoken at home negatively correlated with proportion of este/esta-usage. Children exposed to abundant Spanish in the home patterned like adult monolingual Spanish speakers, producing este/esta for proximal referents and ese/esa for distal referents. By contrast, children who experienced restricted input in Spanish produced mostly ese/esa, regardless of spatial location of the referent. The results suggest that restricted input in Spanish yields a developmental trajectory with overgeneralization of ese/esa rather than este/esta. Importantly, we argue thatthe identification of two groups of child heritage speakers who exhibit different developmental pathways lends itself to differentiated instruction in the heritage language classroom.

Objectives: This study investigates the influence of lexical knowledge, progressive aspect, and verb type on bilingual children’s direct object expression in Spanish. Methodology: Sixty-one child heritage speakers of Spanish, ages 3;3-8;8, and 10 Spanish-speaking adults in the United States completed a task designed to elicit Spanish transitive verbs and direct objects. The children’s comprehension of Spanish vocabulary was measured by a standardized test. Data and Analysis: The children produced 743 transitive verbs, which were coded for grammatical aspect, comparing progressive and non-progressive forms, and for whether the verbs were “mixed” (verbs that routinely occur with or without a direct object among adults) or “non-mixed” (verbs that generally occur with a direct object among adults). Findings: The adults rarely omitted directed objects, whereas the children frequently did. Mixed-effects logistic regression analyses demonstrate that the higher the children’s Spanish vocabulary score, the less they omitted. Furthermore, progressive verb forms and mixed verbs increased the likelihood of omission. The progressive effect is interpreted as a reflection of children’s tendency to associate atelicity with intransitivity. The mixed-verb effect is interpreted as reflecting a lack of understanding of the discourse conditions that render omission infelicitous with mixed verbs. These two verb-level effects dissipated with age, suggesting a loosening of the atelicity–intransitivity association and an increasing awareness of the discourse conditions that guide direct object expression. Originality: The study demonstrates that bilingual children’s omission patterns are guided by progressive aspect and verb type, thus revealing an intricate and nuanced developmental pathway. Implications: While previous research has shown that bilingual children omit more direct objects than monolingual children, this study reveals important systematicities in bilingual children’s omission patterns. Studying child heritage speakers’ grammars in their own right paves the way for a deeper understanding of the systematic nature of the developing heritage grammar.

Recent discoveries of extreme cellular diversity in the brain warrant rapid development of technologies to access specific cell populations within heterogeneous tissue. Available approaches for engineering-targeted technologies for new neuron subtypes are low yield, involving intensive transgenic strain or virus screening. Here, we present Specific Nuclear-Anchored Independent Labeling (SNAIL), an improved virus-based strategy for cell labeling and nuclear isolation from heterogeneous tissue. SNAIL works by leveraging machine learning and other computational approaches to identify DNA sequence features that confer cell type-specific gene activation and then make a probe that drives an affinity purification-compatible reporter gene. As a proof of concept, we designed and validated two novel SNAIL probes that target parvalbumin-expressing (PV+) neurons. Nuclear isolation using SNAIL in wild-type mice is sufficient to capture characteristic open chromatin features of PV+ neurons in the cortex, striatum, and external globus pallidus. The SNAIL framework also has high utility for multispecies cell probe engineering; expression from a mouse PV+ SNAIL enhancer sequence was enriched in PV+ neurons of the macaque cortex. Expansion of this technology has broad applications in cell type-specific observation, manipulation, and therapeutics across species and disease models.

Recent discoveries of extreme cellular diversity in the brain warrant rapid development of technologies to access specific cell populations, enabling characterization of their roles in behavior and in disease states. Available approaches for engineering targeted technologies for new neuron subtypes are low-yield, involving intensive transgenic strain or virus screening. Here, we introduce SNAIL (Specific Nuclear-Anchored Independent Labeling), a new virus-based strategy for cell labeling and nuclear isolation from heterogeneous tissue. SNAIL works by leveraging machine learning and other computational approaches to identify DNA sequence features that confer cell type-specific gene activation and using them to make a probe that drives an affinity purification-compatible reporter gene. As a proof of concept, we designed and validated two novel SNAIL probes that target parvalbumin-expressing (PV) neurons. Furthermore, we show that nuclear isolation using SNAIL in wild type mice is sufficient to capture characteristic open chromatin features of PV neurons in the cortex, striatum, and external globus pallidus. Expansion of this technology has broad applications in cell type-specific observation, manipulation, and therapeutics across species and disease models.

This chapter reviews research on bilingual children's Spanish morphosyntax. The review focuses primarily on Latin children in the United States who are exposed to Spanish at home and are often English-dominant bilinguals. The chapter presents the term 'heritage speakers' when referring to children who are acquiring Spanish in the U. S. It also sometimes considers these heritage speakers as English-Spanish bilinguals, especially when highlighting the role that English plays in the children's acquisition of Spanish. The chapter provides broad generalizations from the literature, and interprets those generalizations within current theories of language acquisition and bilingualism. In particular, two questions are explored: Do child heritage speakers and monolingual children acquire Spanish morphosyntax at the same rate? Do child heritage speakers' morphosyntactic patterns reflect influence from English? The literature suggests that reduced exposure to Spanish results in slower acquisition of Spanish morphosyntax.

In 2010, all young patients treated for intrathoracic Hodgkin lymphoma (HL) at one of 10 radiotherapy centers in the province of Quebec received 3D conformal photon therapy. These patients may now be at risk for late effects of their treatment, notably secondary malignancies and cardiac toxicity. We hypothesized that more complex radiotherapy, including intensity‐modulated proton therapy (IMPT) and possibly IMRT (in the form of helical tomotherapy (HT)), could benefit these patients. With institutional review board approval at 10 institutions, all treatment plans for patients under the age of 30 treated for HL during a six‐month consecutive period of 2010 were retrieved. Twenty‐six patients were identified, and after excluding patients with extrathoracic radiation or treatment of recurrence, 20 patients were replanned for HT and IMPT. Neutron dose for IMPT plans was estimated from published measurements. The relative seriality model was used to predict excess risk of cardiac mortality. A modified linear quadratic model was used to predict the excess absolute risk for induction of lung cancer and, in female patients, breast cancer. Model parameters were derived from published data. Predicted risk for cardiac mortality was similar among the three treatment techniques (absolute excess risk of cardiac mortality was not reduced for HT or IMPT (p>0.05,p>0.05) as compared to 3D CRT). Predicted risks were increased for HT and reduced for IMPT for secondary lung cancer (p

American Sign Language (ASL) makes extensive use of pointing signs, but there has been only limited documentation of how pointing signs are used for demonstrative functions. We elicited demonstratives from four adult Deaf signers of ASL in a puzzle completion task. Our preliminary analysis of the demonstratives produced by these signers supports three important conclusions in need of further investigation. First, despite descriptions of four demonstrative signs in the literature, participants expressed demonstrative function 95% of the time through pointing signs. Second, proximal and distal demonstrative referents were not distinguished categorically on the basis of different demonstrative signs, nor on the basis of pointing handshape or trajectory. Third, non-manual features including eye gaze and facial markers were essential to assigning meaning to demonstratives. Our results identify new avenues for investigation of demonstratives in ASL.

Highlights • The first awake-rat model of explosive blast-induced traumatic brain injury (blast-TBI). • Rats with blast-TBI developed ongoing, spontaneous pain. • Blast-TBI did not result in persistent changes in activity of thalamic or spinal neurons, or in gliosis in these structures., Explosive blast-induced traumatic brain injury (blast-TBI) in military personnel is a leading cause of injury and persistent neurological abnormalities, including chronic pain. We previously demonstrated that chronic pain after spinal cord injury results from central sensitization in the posterior thalamus (PO). The presence of persistent headaches and back pain in veterans with blast-TBI suggests a similar involvement of thalamic sensitization. Here, we tested the hypothesis that pain after blast-TBI is associated with abnormal increases in activity of neurons in PO thalamus. We developed a novel model with two unique features: (1) blast-TBI was performed in awake, un-anesthetized rats, to simulate the human experience and to eliminate confounds of anesthesia and surgery inherent in other models; (2) only the cranium, rather than the entire body, was exposed to a collimated blast wave, with the blast wave striking the posterior cranium in the region of the occipital crest and foramen magnum. Three weeks after blast-TBI, rats developed persistent, ongoing spontaneous pain. Contrary to our hypothesis, we found no significant differences in the activity of PO neurons, or of neurons in the spinal trigeminal nucleus. There were also no significant changes in gliosis in either of these structures. This novel model will allow future studies on the pathophysiology of chronic pain after blast-TBI.

AIM: To re-examine whether hepatic vein thrombosis (HVT) (classical Budd-Chiari syndrome) and hepatic vena cava-Budd Chiari syndrome (HVC-BCS) are the same disorder. METHODS: A systematic review of observational studies conducted in adult subjects with primary BCS, hepatic vein outflow tract obstruction, membranous obstruction of the inferior vena cava (IVC), obliterative hepatocavopathy, or HVT during the period of January 2000 until February 2015 was conducted using the following databases: Cochrane Library, CINAHL, MEDLINE, PubMed and Scopus. RESULTS: Of 1299 articles identified, 26 were included in this study. Classical BCS is more common in women with a pure hepatic vein obstruction (49%-74%). HVC-BCS is more common in men with the obstruction often located in both the inferior vena cava and hepatic veins (14%-84%). Classical BCS presents with acute abdominal pain, ascites, and hepatomegaly. HVC-BCS presents with chronic abdominal pain and abdominal wall varices. Myeloproliferative neoplasms (MPN) are the most common etiology of classical BCS (16%-62%) with the JAK2V617-F mutation found in 26%-52%. In HVC-BCS, MPN are found in 4%-5%, and the JAK2V617-F mutation in 2%-5%. Classical BCS responds well to medical management alone and 1st line management of HVC-BCS involves percutaneous recanalization, with few managed with medical management alone. CONCLUSION: Systematic review of recent data suggests that classical BCS and HVC-BCS may be two clinically different disorders that involve the disruption of hepatic venous outflow.