Tablet use in schools: a critical review of the evidence for learning outcomes

The increased popularity of tablets in general has led to uptake in education. We critically review the literature reporting use of tablets by primary and secondary school children across the curriculum, with a particular emphasis on learning outcomes. The systematic review methodology was used, and our literature search resulted in 33 relevant studies meeting the inclusion criteria. A total of 23 met the minimum quality criteria and were examined in detail (16 reporting positive learning outcomes, 5 no difference and 2 negative learning outcomes). Explanations underlying these observations were analysed, and factors contributing to successful uses of tablets are discussed. While we hypothesize how tablets can viably support children in completing a variety of learning tasks (across a range of contexts and academic subjects), the fragmented nature of the current knowledge base, and the scarcity of rigorous studies, makes it difficult to draw firm conclusions. The generalizability of evidence is limited, and detailed explanations as to how, or why, using tablets within certain activities can improve learning remain elusive. We recommend that future research moves beyond exploration towards systematic and in‐depth investigations building on the existing findings documented here.     

Serotonin-deficient mutants and male mating behavior in the nematode Caenorhabditis elegans

Defining a behavior that requires the function of specific neurons in the free-living nematode Caenorhabditis elegans can allow one to screen for mutations that disrupt the specification or function of those neurons. We identified serotonin-immunoreactive neurons required for tail curling or "turning" behavior exhibited by C. elegans males during mating. Males mutant in three different genes that reduce serotonin expression, cat-1, cat-4, and bas-1, exhibited defects in turning behavior similar to those of wild-type males in which these neurons were ablated. The turning defect of cat-4 males was rescued by exogenous serotonin, consistent with the idea that their behavioral defect is caused by a lack of serotonin. While the serotonin-deficient mutants we analyzed shared certain behavioral traits, they were blocked for serotonin synthesis at different steps. Analysis of these and additional serotonin-deficient mutants may help us understand how a neuron controls the expression of a serotonergic phenotype.     

The synthesis of elastin, collagen, and glycosaminoglycans by high density primary cultures of neonatal rat aortic smooth muscle. An ultrastructural and biochemical study

Primary cultures of neonatal rat aortic smooth muscle cells inoculated at high densities (1 X 10(6) cells/25 cm2 Falcon flask) with adequate nutrient media and pH control grow rapidly and form multilayers of cells with typical "hill and valley" organization. After 10 days growth insoluble elastin formation could be visualized by phase contrast microscopy as small particles which grew rapidly to become larger irregular refractile aggregates and later coalesced to form larger aggregates and small fibres. With light and electronmicroscopy, elastin was the predominant matrix protein formed, with the "hill regions" of cultures containing abundant elastin aggregates and some collagen. In 2-week-old cultures differentiation could be observed within the cell multilayer. The older deeper cells contained more protein synthesis organelles and myofilaments and were in close association with large often coalescing elastin aggregates; compared to younger more superficial cells which contained more free polyribosomes less myofilaments, and were associated with fewer and small elastin aggregates. In older cultures this differentiation was not apparent; the cells contained many myofilaments, dense bodies, and lysosomes. Elastin aggregates and newly formed elastic fibres were abundant in the matrix. Quantitative analysis of insoluble elastin formation in the cell layer during the 4-week culture period indicated continuous biosynthesis and deposition which paralleled that of desmosine formation. Amino-acid analysis of a hot alkali insoluble residue (regarded as elastin) from 30-day-old cultures gave a profile identical with neonatal rat aortic elastin in vivo. Insoluble collagen formation in the cell layer tended to plateau after the log phase of growth was completed (10 days). Proteoglycans were found predominantly in the supernatant media. Glycosaminoglycan analysis revealed a profile of dermatan sulphate (32%), chondroitin 4-sulphate (43%), keratan and heparan sulphate (30%), with only a trace of hyaluronic acid. This study indicates that primary cultures of neonatal rat aortic smooth muscle cells remain differentiated in culture and have the unique capacity to continue to synthesize and deposit large amounts (mg) of insoluble elastin which aggregate and from elastic fibres in vitro.     

The influence of taking uterine biopsies on the concentration of some steroids in the blood and in the uterus, on the ovarian activity, and on the sexual behaviour of the mare

It has been shown that stimulation of the uterus of mares by the daily taking of biopsies can result in the occurrence of oestrous symptoms. This is accompanied by some follicular growth and a progesterone content in the blood often higher than 1 ng/ml. The following observations suggest that this progesterone originates in the uterus and not in the ovaries: (1) no active corpora lutea appeared to be present in the ovaries after ovariectomy, (2) ovariectomized mares showed the same oestrous symptoms in similar experiments and even mating took place, (3) in the uterine biopsies the concentration of the compound referred to as "5.4", which is assumed to be easily convertible into progesterone, had already increased considerably in the second biopsy, (4) administration of stilboestrol reduced the rise of the progesterone level in the uterine biopsies as well as in the blood. The absence of oestradiol-17 beta in the ovarian follicles and the fact that ovariectomized mares also come into heat suggest that oestrogens cannot be held responsible for the oestrous symptoms in these mares. Our experiments demonstrate that the uterus can be involved in sexual behaviour and the formation of steroids.     

Insertion element IS3-based PCR method for subtyping Escherichia coli O157:H7

An Escherichia coli O157:H7 subtyping method based on PCR amplification of variable DNA sequences between the repetitive element IS3 was developed. Template DNA was prepared by boiling cells in Chelex. Two separate IS3 PCR amplifications were performed for each isolate: one with a single primer (primer IS3A) and one with two primers (primers IS3A and IS3B). The IS3 PCR subtyping method was applied to 35 epidemiologically related and unrelated E. coli O157:H7 isolates that had been previously characterized by pulsed-field gel electrophoresis (PFGE). PFGE identified 25 different subtypes (difference of one or more bands). PCR with single primer IS3A and primer pair IS3A-IS3B identified 6 and 14 different subtypes, respectively. By combining the results of the two PCR amplifications, 15 different IS3 PCR subtypes were identified. While not as sensitive as PFGE, IS3 PCR subtyping grouped all outbreak-related isolates. IS3 PCR banding patterns were reproducible between amplifications and between subcultures. IS3 PCR could serve as a simple, rapid screening method for the identification of unrelated E. coli O157:H7 isolates.