Developing use of strategy in childhood mental addition

The aim of this research was to look at the strategies used by children when doing mental addition problems of the varying levels of complexity. An authentic arithmetic task was designed for use in a school environment. The central aim was to study developing fluency in mental arithmetic as achieved through recruiting various strategies into solving more complex problems than those studied by existing research. The nature of mental addition strategies was inferred from children's solution times when doing sequences of sums. Three studies were carried out on 7–11 year-old children from two local schools. [Continues.

Synaptic nanomodules underlie the organization and plasticity of spine synapses.

Experience results in long-lasting changes in dendritic spine size, yet how the molecular architecture of the synapse responds to plasticity remains poorly understood. Here a combined approach of multicolor stimulated emission depletion microscopy (STED) and confocal imaging in rat and mouse demonstrates that structural plasticity is linked to the addition of unitary synaptic nanomodules to spines. Spine synapses in vivo and in vitro contain discrete and aligned subdiffraction modules of pre- and postsynaptic proteins whose number scales linearly with spine size. Live-cell time-lapse super-resolution imaging reveals that NMDA receptor-dependent increases in spine size are accompanied both by enhanced mobility of pre- and postsynaptic modules that remain aligned with each other and by a coordinated increase in the number of nanomodules. These findings suggest a simplified model for experience-dependent structural plasticity relying on an unexpectedly modular nanomolecular architecture of synaptic proteins

A membrane model for cytosolic calcium oscillations. A study using Xenopus oocytes

Cytosolic calcium oscillations occur in a wide variety of cells and are involved in different cellular functions. We describe these calcium oscillations by a mathematical model based on the putative electrophysiological properties of the endoplasmic reticulum (ER) membrane. The salient features of our membrane model are calcium-dependent calcium channels and calcium pumps in the ER membrane, constant entry of calcium into the cytosol, calcium dependent removal from the cytosol, and buffering by cytoplasmic calcium binding proteins. Numerical integration of the model allows us to study the fluctuations in the cytosolic calcium concentration, the ER membrane potential, and the concentration of free calcium binding sites on a calcium binding protein. The model demonstrates the physiological features necessary for calcium oscillations and suggests that the level of calcium flux into the cytosol controls the frequency and amplitude of oscillations. The model also suggests that the level of buffering affects the frequency and amplitude of the oscillations. The model is supported by experiments indirectly measuring cytosolic calcium by calcium-induced chloride currents in Xenopus oocytes as well as cytosolic calcium oscillations observed in other preparations

Pengaruh Sudut Kaca Penutup Dan Jenis Kaca Terhadap Efisiensi Kolektor Surya Pada Proses Destilasi Air Laut

Distillation system in terms of filtering sea water using solar power, the absorption of radiation plays important role for it functions is as solar radiation absorber and is to convert the radiation into heat energy. Glass cover that will be used on the solar collector is transparent glass and frosted glass. Have ben research, the writer would like to analyze the effects of angles of the glass cover and of the glass types toward the efficiency of the heat collector during the process of sea water distillations with the variant angel of 25o, 35o and 55o. The result shown that the variation on angel and the types of the glass covers, both transparent glass and frosted glass is different each other. The obtained result is that the highest efficiency is on the transparent glass cover with the glass angle declivity of 55o and the average value is of 46,78 % and the lowest is on the frosted glass cover with the angle glass declivity of 25o and the average value is of 42.60 %. While the highest amount of water distillations is on the transparent glass with the angle glass declivity of 25o and the average value is of 92.20 mL and the lowest of water amount is on the frosted glass with angle glass declivity of 55o and the average value is of 32.13 mL. Therefore, in the process of sea water distillations, it is better to use transparent glass cover as the collector with the angle glass declivity of 25o. However, the distance of plate absorber and the glass cover should be high so that the volume of heat room is large and the total amount of heat loss thrown from the solar collector is little to the surrounding

Altered Platelet Function in Patients with Severe Congestive Heart Failure

Platelet function was assessed in 15 patients with severe congestive heart failure (CHF) and in 26 control subjects of similar ages. The platelet count (mm3), surface reactivity, aggregometry studies, release factors, and circulating aggregates were investigated. The mean number of circulating platelets was normal, but a hyperactive platelet response was found in 53% of the CHF patients. CHF patients had a 42% mean for the spread type platelet, and the average number of aggregates was 64: control subjects had a 12% mean for the spread type platelet, and the average number of aggregates was 40 (p \u3c 0.05). Aggregation with all of the inducers was normal, although 27% of CHF patients showed spontaneous aggregation. The mean plasma levels of both platelet factor 4 and betathromboglobulin were abnormally elevated. No circulating platelet aggregates were detected. Our studies indicate that platelet function is abnormal in patients with CHF. The abnormal platelet reactivity found might contribute to the increased incidence of thromboembolic events observed in CHF patients

Prevalence, distribution and antibiotic resistance of emergent Arcobacter spp. from clinically healthy cattle and goats

Prevalence, distribution and antibiotic resistance of Arcobacter spp. were investigated in cattle, goats, floor and treated water samples in this study. The prevalence of Arcobacter in adult and young was recorded as 8/110 (7.27%) and 4/83 (4.81%), respectively, which showed insignificant difference (P = 0.3503) in detection rates between adult and young cattle. A total of 33.33% of the floor samples and 11.11% of the treated water samples analysed were determined as positive for Arcobacter. Among the species isolated, over all, A. butzleri (45%) was the most frequently detected species, followed by A. skirrowii (5%). A. butzleri was isolated from adult cattle, floor and water samples at the rates of 75.0%, 33.4% and 50%, respectively. Co-colonization of species was not uncommon, and 50% of the samples were carrying more than one Arcobacter species. Only 12.5% sample from cattle (adult) was detected positive for only A. skirrowii. All samples from young animals, floor and water contained mixed isolates. None of the samples from goat farm was found to be carrying Arcobacter species. On profiling of antimicrobial resistance patterns, it was found that only one A. butzleri isolate (3.7%) was sensitive to all nine antibiotics tested. A. butzleri was found highly resistant to ampicillin (55.6%), followed by cefotaxime (33.4%) and ciprofloxacin (33.4%). Overall, 20% of the isolates showed multidrug resistance (resistant ≥4 antibiotics). Gentamicin and enrofloxacin can be used as drugs of choice for the treatment for Arcobacter infection