Counting-on, trading and partitioning: effects of training and prior knowledge on performance on Base-10 tasks

Factors affecting performance on Base-10 tasks were investigated in a series of four studies with a total of 453 children aged five to seven years. Training in counting-on was found to enhance child performance on Base-10 tasks (Studies 2, 3, and 4), while prior knowledge of counting-on (Study 1), trading (Studies 1 and 3) and partitioning (Studies 1 and 4) were associated with enhanced Base-10 performance. It emerged that procedural knowledge of counting-on, trading and partitioning can lead to improvements in procedural knowledge of the Base-10 system. The findings lend support to the model of iterative development of conceptual and procedural knowledge advanced by Rittle-Johnson, Siegler and Alibali (2001)

The prompt hypothesis: clarification requests as corrective input for grammatical errors

The potential of clarification questions (CQs) to act as a form of corrective input for young children's grammatical errors was examined. Corrective responses were operationalized as those occasions when child speech shifted from erroneous to correct (E -> C) contingent on a clarification question. It was predicted that E -> C sequences would prevail over shifts in the opposite direction (C -> E), as can occur in the case of nonerror-contingent CQs. This prediction was tested via a standard intervention paradigm, whereby every 60s a sequence of two clarification requests (either specific or general) was introduced into conversation with a total of 45 2- and 4-year-old children. For 10 categories of grammatical structure, E -> C sequences predominated over their C -> E counterparts, with levels of E -> C shifts increasing after two clarification questions. Children were also more reluctant to repeat erroneous forms than their correct counterparts, following the intervention of CQs. The findings provide support for Saxton's prompt hypothesis, which predicts that error-contingent CQs bear the potential to cue recall of previously acquired grammatical forms

Negative evidence and negative feedback: immediate effects on the grammaticality of child speech

Until recently, a long-standing assumption in the field of child language acquisition research was that parents do not correct the grammatical errors of their children. While consensus now exists that potentially corrective responses are often supplied, controversy persists as to whether the child can identify and exploit such information in practice. To address these issues, this study adopts the contrast theory of negative input as a framework for analysis (Saxton 1995). In this theory, two distinct kinds of corrective input are identified, termed negative evidence and negative feedback, respectively. The corrective potential of each category was investigated by examining the immediate effects of each on the grammaticality of child speech. A longitudinal corpus of naturalistic data (49 hours) from a single child were analysed with respect to 11 grammatical categories. The effects of negative input were compared with two non-corrective sources of input, namely positive input and adult move-ons. It was found that grammatical forms were more frequent in child speech following negative evidence and negative feedback than either of the two non-corrective sources of input. In light of these, and related, findings, it is argued that corrective input may well prove important in explanations for how the child eventually retreats from error to attain a mature system of grammar

Constraints on Primary Production in Lake Erie

The Laurentian Great Lake, Lake Erie is an invaluable global resource and its watershed is home to over 11 million people. The pressures placed on the lake because of this high population caused Lake Erie to experience numerous environmental problems, including seasonal hypoxia and harmful algal blooms. While these topics have been widely studied in Lake Erie for over 40 years a more nuanced understanding of the interaction between phytoplankton and nutrient is needed to properly address the problems continuing to face the lake. In this study we combine classical limnological and cell growth experiments with modern molecular biological techniques and microscopy to more completely describe the aquatic microbial ecology of the lake. We used an oxalate rinse technique to examine the surface absorbed P pool of the toxic cyanobacterium Microcystis aeruginosa grown under a range of P conditions, as well as the general Lake Erie plankton assemblage. Our results suggest that while Microcystis is plastic in its cellular P needs, the ratio of intracellular to extracellular P remains stable across growth conditions. We describe the effect of the phosphonate herbicide glyphosate on the Lake Erie phytoplankton community using laboratory cell growth studies, field microcosm experiments and PCR amplification of a gene implicated in the breakdown of this compound from the environment. Results from these experiments suggest that the presence of glyphosate can affect community structure in multiple ways and may explain areas of unexplained phytoplankton diversity in coastal areas of Lake Erie. We also show heterotrophic bacteria are likely critical to the breakdown of glyphosate and further illustrate that understanding the context of the larger microbial community is critical to understanding the ecology of the constituent members of the community. Finally, we investigate the activity of the phytoplankton community in winter months with a focus on diatoms abundant in Lake Erie under the ice. We show these diatoms are active and that the winter bloom is a likely source of carbon important to seasonal hypoxia formation. Together, these studies significantly enrich our understanding of how phytoplankton influence important ecological processes in Lake Erie

'No Negative Evidence': What's the Problem?

Proceedings of the Twenty-Second Annual Meeting of the Berkeley Linguistics Society: General Session and Parasession on The Role of Learnability in Grammatical Theory (1996

Basic calculation proficiency and mathematics achievement in elementary school children

The relation between skill in simple addition and subtraction and more general math achievement in elementary school is well established but not understood. Both the intrinsic importance of skill in simple calculation for math and the influence of conceptual knowledge and cognitive factors (working memory, processing speed, oral language) on simple calculation and math are plausible. The authors investigated the development of basic calculation fluency and its relations to math achievement and other factors by tracking a group of 259 United Kingdom English children from second to third grade. In both grades the group did not retrieve the solutions to most problems, but their math achievement was typical. Improvement in basic calculation proficiency was partially predicted by conceptual knowledge and cognitive factors. These factors only partially mediated the relation between basic calculation and math achievement. The relation between reading and math was wholly mediated by number measures and cognitive factors

Effects of Pulsed Electric Field (PEF) Preprocessing During Maceration for Red Wine Processing of Idaho Wines: Analysis of Polyphenol Content in Sangiovese Red Wine

The wine industry has created around 70 wineries in Idaho and has had a $209.6 million impact on its economy. The cool climate has made white wines its top-produced wine, however, Idaho has recently been focusing on increasing production of red wines. Sangiovese grapes are a light red color, so producers are interested in increasing the strength of the color pigment. Red wine is produced through the maceration of grapes. Maceration is the process where grapes soak in their juice after being crushed to extract color and flavor from their skins. The maceration time is around 7 days, and producers hope to decrease that time to increase wine production

Effect of age on cutaneous vasomotor responses during local skin heating

This study examined the effect of ageing on the low-frequency oscillations (vasomotion) of skin blood flow in response to local heating (LH). Skin blood flow was assessed by laser-Doppler flowmetry on the forearm at rest (33 °C) and in response to LH of the skin to both 42 °C and 44 °C in 14 young (24 ± 1 years) and 14 older (64 ± 1 years) participants. Vasomotion was analyzed using a wavelet transform to investigate power of the frequency intervals associated with endothelial, neural, myogenic, respiratory, and cardiac activities of the laser-Doppler signal. Laser-Doppler flux increased in both groups with LH (both d > 1.8, p 1.2, p 0.9, p 0.7), myogenic (d = 0.3, p > 0.7), respiratory (d = 0.4, p > 0.6), and cardiac (d = 0.1, p > 0.7) frequency intervals. These data indicate that LH increases cutaneous endothelial and myogenic activity, while decreasing neural activity. Furthermore, ageing reduces the increase in cutaneous endothelial activity in response to LH

Plasticity of Total and Intracellular Phosphorus Quotas in Microcystis aeruginosa Cultures and Lake Erie Algal Assemblages

Blooms of the potentially toxic cyanobacterium Microcystis are common events globally, and as a result significant resources continue to be dedicated to monitoring and controlling these events. Recent studies have shown that a significant proportion of total cell-associated phosphorus (P) in marine phytoplankton can be surface adsorbed; as a result studies completed to date do not accurately report the P demands of these organisms. In this study we measure the total cell-associated and intracellular P as well as growth rates of two toxic strains of Microcystis aeruginosa Kütz grown under a range of P concentrations. The results show that the intracellular P pool in Microcystis represents a percentage of total cell-associated P (50–90%) similar to what has been reported for actively growing algae in marine systems. Intracellular P concentrations (39–147 fg cell−1) generally increased with increasing P concentrations in the growth medium, but growth rate and the ratio of total cell-associated to intracellular P remained generally stable. Intracellular P quotas and growth rates in cells grown under the different P treatments illustrate the ability of this organism to successfully respond to changes in ambient P loads, and thus have implications for ecosystem scale productivity models employing P concentrations to predict algal bloom events

Transcriptional responses of Arabidopsis thaliana plants to As (V) stress

Background Arsenic is toxic to plants and a common environmental pollutant. There is a strong chemical similarity between arsenate [As (V)] and phosphate (Pi). Whole genome oligonucleotide microarrays were employed to investigate the transcriptional responses of Arabidopsis thaliana plants to As (V) stress. Results Antioxidant-related genes (i.e. coding for superoxide dismutases and peroxidases) play prominent roles in response to arsenate. The microarray experiment revealed induction of chloroplast Cu/Zn superoxide dismutase (SOD) (at2g28190), Cu/Zn SOD (at1g08830), as well as an SOD copper chaperone (at1g12520). On the other hand, Fe SODs were strongly repressed in response to As (V) stress. Non-parametric rank product statistics were used to detect differentially expressed genes. Arsenate stress resulted in the repression of numerous genes known to be induced by phosphate starvation. These observations were confirmed with qRT-PCR and SOD activity assays. Conclusion Microarray data suggest that As (V) induces genes involved in response to oxidative stress and represses transcription of genes induced by phosphate starvation. This study implicates As (V) as a phosphate mimic in the cell by repressing genes normally induced when available phosphate is scarce. Most importantly, these data reveal that arsenate stress affects the expression of several genes with little or unknown biological functions, thereby providing new putative gene targets for future research