What is important in electronic textbooks for students of different achievement levels?

This paper reports the findings of a study that explored which characteristics of electronic textbooks correlated with knowledge acquisition by learners of different achievement levels. The study was carried out on 35 units of electronic textbooks that were studied by 19 high-achieving and 19 low-achieving students in four Estonian schools. The low-achieving students profited from clear instructions, familiar icons, examples, and answering from the keyboard. The high-achieving students benefited from key-combinations, menus with different levels, the Internet, analogies and lower density of terms in the content of the material. In electronic textbooks, not only the content, but also the design of the software, should be different for learners with a different achievement level.     

In a big boost for the Federal Arbitration Act,the Supreme Court decides in Preston v. Ferrer that the arbitrator remains supreme

The U.S. Supreme Court hands down the first decision from a 2007‐08 docket that now includes four arbitration cases. Michael E. Johnson and Piret Loone, of New York, who wrote the January preview of the Preston v. Ferrer case, return to analyze the Court's holding that the Federal Arbitration Act preempts a California statute that a state appeals court had said sent a management contract dispute to the state's labor commissioner before the arbitrator.     

Within-herd prevalence of intramammary infection caused by Mycoplasma bovis and associations between cow udder health,milk yield,and composition

Subclinical mastitis is one of the major health problems in dairy herds due to decreased milk production and reduced milk quality. The aim of this study was to examine the within-herd prevalence of subclinical intramammary infection caused by Mycoplasma bovis and to evaluate associations between M. bovis and cow daily milk yield, udder health, and milk composition. Individual cow composite milk samples (n = 522) were collected from all lactating dairy cows in 1 Estonian dairy farm in November 2014. Daily milk yield, days in milk, and parity were recorded. Collected milk samples were analyzed for somatic cell count, milk protein, fat, and urea content. The presence of M. bovis, Staphylococcus aureus, Streptococcus agalactiae, and Streptococcus uberis in the milk samples was confirmed by quantitative PCR analysis. The within-herd prevalence of M. bovis was 17.2% in the study herd. No association was observed between days in milk and parity to the presence of M. bovis in milk. According to linear regression analysis, the daily milk yield from cows positive for M. bovis was on average 3.0 kg lower compared with cows negative for M. bovis. In addition, the presence of M. bovis in milk samples was significantly associated with higher somatic cell count and lower fat and urea content compared with milk samples negative for M. bovis. In conclusion, subclinical M. bovis intramammary infection is associated with decreased milk yield and lower milk quality.     

Interfaces between dendritic cells, other immune cells, and nerve fibres in mouse Peyer's patches: potential sites for neuroinvasion in prion diseases

In this study, we examined where immune cells and nerve fibres are located in mouse Peyer's patches, with a view to identifying potential sites for neuroinvasion by prions. Special attention was paid to dendritic cells, viewed as candidate transporters of infectious prion. Double immunofluorescence labellings with anti-CD11c antibody and marker for other immune cells (B cells, T cells, follicular dendritic cells) were carried out and analysed by confocal microscopy on Peyer's patch cryosections. To reveal the extensive ganglionated networks of the myenteric and submucosal plexi and the sparse meshworks of nerve strands, we used antibodies directed against different neurofilament subunits or against glial fibrillary acidic protein. In the suprafollicular dome, dendritic cells connect, via their cytoplasmic extensions, enterocytes with M cells of the follicle-associated epithelium. They are also close to B and T cells. Nerve fibres are detected in the suprafollicular dome, notably in contact with dendritic cells. Similar connections between dendritic cells, T cells, and nerve fibres are seen in the interfollicular region. Germinal centres are not innervated; inside them dendritic cells establish contacts with follicular dendritic cells and with B cells. After immunolabelling of normal prion protein, dendritic cells of the suprafollicular dome are intensely positive labelled.     

Diarrhea caused by Cryptosporidium as the initial manifestation of AIDS in an elderly man

Reproductive history of mothers of 115 Down's syndrome children was studied and compared with 200 control mothers who gave birth to normal children. The frequency of spontaneous abortions in mothers of Down's syndrome babies was found to be elevated significantly (p < 0.05). The data suggest that the maternal health and reproductive potential have a prominent aetiological significance in the occurrence of Down's syndrome.     

Optimizing bismuth control during copper production

Base metal quality requirements necessitate the application of effective processes for adequate impurity elimination and tight control of operations to cope with impurity level fluctuations. In copper, lead, and tin, specified levels of bismuth are 1 ppm, 50–100 ppm, and 100–500 ppm, respectively. In copper’production, existing bismuth removal processes are being improved and new ones are being developed and introduced commercially.     

Two results on the permuting mailbox channel

Two problems of information transmission on the permuting mailbox (or relay) channel are considered. Such a channel is characterized by the cardinality ε of the alphabet and the number b of letters in the mailbox. In the case b=1, an upper bound is obtained on the achievable rate in the jamming situation. In the case ε=2, it is proven that time-sharing is not always the best solution when both main users wish to transmit information to a third user