A Study of the Use of High-Power Medium-Wave Broadcasting Transmitters in the European Area

An engineering study has been made of the use of high-power transmitters for providing medium-wave broadcasting service in Europe and the nearby areas of North Africa and the Middle East. The purpose of the study is to acquaint American broadcasting engineers with the experience and problems which have resulted from medium-wave broadcasting allocations and operations in the European area in recent years. The Clear Channel stations operating in the United States have, for some time, recommended the use of transmitter powers considerably higher than the present maximum limit of 50 kW which is set forth in the FCC rules. Only limited experimental operation with high power has been permitted in the United States and it is thus considered to be of interest to examine the results obtained with high-power broadcasting in Europe.     

Abuse against women in rural Minnesota

Several botanicals, including Crataegus oxycantha, Terminalia arjuna, Inula racemosa, and Astragalus membranaceus, have been found to have therapeutic benefit for the treatment of cardiovascular disease. Crataegus oxycantha has been used traditionally as a cardiac tonic and current uses include treatment for angina, hypertension, arrhythmias, and congestive heart failure. Animal studies have also indicated that Crataegus extracts may also have potential use as anti-ischemic and lipid-lowering agents. The bark of the Terminalia arjuna tree has a long history of use as a cardiac tonic as well, and has been indicated in the treatment of coronary artery disease, heart failure, hypercholesterolemia and for relief of anginal pain. Additionally, it has been found to have antibacterial and antimutagenic properties. Inula racemosa, also known as Pushkarmoola, is another traditional Ayurvedic botanical that has potential cardioprotective benefit. In human trials, a combination of Inula racemosa and Commiphora mukul was shown to be superior to nitroglycerin in reducing the chest pain and dyspnea associated with angina. Astragalus membranaceus, a Chinese herb, is often used as a "Qi tonifier" and has been studied for its therapeutic benefit in treatment of ischemic heart disease, myocardial infarction, heart failure, and relief of anginal pain. Clinical studies have indicated that its in vitro antioxidant activity is the mechanism by which it affords its cardioprotective benefit.     

Optical trapping force reduction and manipulation of nanoporous beads

We studied the interaction of infrared optical traps with controlled-pore glass (CPG) beads in aqueous medium. The lateral optical trapping force and stiffness were experimentally found considerably smaller than those of their solid counterparts. The simulation using an average refractive index revealed significant losses of effective trapping efficiency, which quantitatively agreed well with experimentally fitted curves. This effect was ascribed to the reduced relative refractive index of medium-filled CPG beads with respect to the medium. Combining optical trapping with mechanical confinements, we demonstrated a microfluidic platform allowing for the synthesis of multiple DNA oligonucleotide sequences on individual beads of interest.     

Translation and manipulation of silicon nanomembranes using holographic optical tweezers

We demonstrate the use of holographic optical tweezers for trapping and manipulating silicon nanomembranes. These macroscopic free-standing sheets of single-crystalline silicon are attractive for use in next-generation flexible electronics. We achieve three-dimensional control by attaching a functionalized silica bead to the silicon surface, enabling non-contact trapping and manipulation of planar structures with high aspect ratios (high lateral size to thickness). Using as few as one trap and trapping powers as low as several hundred milliwatts, silicon nanomembranes can be rotated and translated in a solution over large distances.     

Can the interactive whiteboard support young children’s collaborative communication and thinking in classroom science activities?

Interactive whiteboards (IWBs) have been widely introduced to English primary schools (5–11 years) in the last decade and this has generated much research interest. In the past, research has focused on IWB-use in teacher-led sessions, attending particularly to the nature of teacher-pupil interaction at the IWB and the apparent motivational advantages for children. In contrast, this study focuses on children’s communication and thinking during their semi-autonomous use of the IWB during collaborative groupwork in primary school science lessons, aiming in part to see if the IWB is suited to this type of use. Over the course of one school year, twelve primary teachers of Years 4 and 5 (8–10 years) took part in a professional development and research programme which involved them in devising a sequence of three science lessons incorporating small-group activity at the IWB. The functionality of the IWB is analysed here as means for supporting the children’s joint communication and thinking, using embedded cues and the availability of certain features in the IWB technology. Our observational analysis of two examples of children’s collaborative activity in different classrooms, together with subsequent group interviews, suggests that the IWB can make some identifiable contributions to children’s productive communication and thinking. However the IWB is not seen to be an entirely distinctive or pedagogically transformative learning resource in the primary classroom. In our developing conceptual framework, the children’s knowledge building is closely related to their active engagement in using IWB affordances and their productive dialogue, essentially supported by the teacher’s scaffolding strategies, the establishment and use of “talk rules” in conversation, and the opportunities and constraints applying in classroom participation structures. These conditions help the children to deal with interconnected social, cognitive, and technical problems arising over time. Certain aspects of this form of computer-supported collaborative learning (CSCL) are discussed. These relate to the integration of the IWB with other classroom learning systems and resources, and to the nature of progression in children’s activity and learning with this new type of highly integrated system of CSCL.     

Crack dynamics and explosive burn via generalized coordinates

The growth of cracks and their role in the formation of hot spots in explosives are addressed in a three-part discussion. First the method of generalized coordinates is used to represent crack dynamics with two ordinary differential equations for crack opening and growth. These account for both stable and unstable behavior. Second, the behavior of burning cracks is addressed by coupling those differential equations to a burn model to show that burning cracks can exhibit either mild or violently unstable behavior. Finally, in the third part, it is shown that the burning crack algorithm in combination with SCRAM (which deals with Statistical CRAck Mechanics) can account for the reactive behavior of a plastic-bonded explosive (PBX 9501) subjected to multiple shocks. SCRAM allows for representation of brittle behavior in a variety of explosives, propellants, ceramics and geological materials. This revised version was published online in June 2006 with corrections to the Cover Date.     

Speed of reading in an adult population under differential conditions.

420 adults read 2 pairs of passages and unknown to them each reading time was recorded. After reading the 1st pair of passages, readers were asked to answer a comprehension question. Irrespective of the difficulty level of the passages, reading times for the pair of passages following the comprehension question were significantly longer than for that preceding it. Substantial positive correlations were found between 1st- and 2nd-pair reading times for both individuals and for passages. Slow readers showed greater increases in reading time for more difficult materials than did fast readers. Evidence of the dubious value of words per minute as a measure of reading speed is presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Curtain Antennas for High-Power HF Broadcasting Applications

The performance of high-power curtain antennas which have been designed for international broadcasting stations is presented along with details of design and construction. The antennas described provide horizontal beamwidths ranging from 190°to 28 °, vertical beamwidths from 4°to 12°, and power gains ranging from 18 to more than 23.5 dB above a half-wave dipole in free space.     

Expressed emotion in families of clinically referred and nonreferred children: Toward a further understanding of the expressed emotion index.

As assessed from a 5-min speech sample, level of expressed emotion (EE) in parents significantly discriminated between families of 7- to 16-year-old children who were referred for mental health treatment and a nonclinical comparison group; however, both groups contained a relatively high proportion of high-EE families. Furthermore, EE independently predicted clinical-nonclincal group status when considered in conjunction with overall family functioning and level of psychological distress in mothers. Findings support the relevance of EE, although the measure showed poor specificity and an analysis of the components that comprise the EE index indicated that only certain components were pertinent. The need to reassess the meaning of the EE construct and strengthen its applicability for the general clinical population of children and families is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)