Sensitized Up—Conversion Luminescence of Ho^3＋ in Nd^3＋—Yb^3＋—Ho^3＋ Co—doped ZrF4—Based Glass

Up-conversion processes for the blue, green and red emissions were found two-photon phenomenon, known as the cooperative phenomenon. This phenomenon was assisted by Nd³⁺ → Yb³⁺ → Ho³⁺ energy transfer. The strong green emission due to the Ho³⁺ : (⁵F₄, ⁵S₂)→ ⁵I₈ transitions was observed in Nd³⁺-Ho³⁺ co-doped ZrF₄-based fluoride glasses under 800 nm excitation. As an attempt to enhance Ho³⁺ up-conversion luminescences in the Nd³⁺ – Ho³⁺ co-doped ZrF₄-based glasses, Yb³⁺ ions were added to the glasses. As a result it was found that, in 800 nm excitation of 60 ZrF₄. 30BaF2. (8-x)LaF₃. lNdF₃. xYbF₃. 1HoF₃ glasses (x=0 to 7), sensitized up-conversion luminescences are observed at around 490 nm (blue), 545 nm (green), and 650 nm (red), which correspond to the Ho³⁺ : ⁵F₃ → ⁵I₈, ( ⁵F₄, ⁵S₂)→⁵I₈ and ⁵F₅→ ⁵I₈ transitions respectively. The intensities of the green and red emissions in a 3 mol % YbF₃-containing glass were about 50 times stronger than those glasses without YbF₃. This is based on sensitization due to Yb³⁺ ions. In particular, the green emission was extremely strong and the Nd³⁺-Yb³⁺-Ho³⁺ co-doped ZrF₄-based glasses have a high possibility of realizing a green up-conversion laser glass. In this paper the up-conversion mechanism in the glasses is discussed in detail.     

AUTISTIC SPECTRUM DISORDERS AND ASIAN CHILDREN

ABSTRACT:  This paper compares the incidence of the diagnosis of Autistic Spectrum Disorders (ASD) among White and Asian children with reference to data obtained from thirteen local education authorities (LEAs) in England. It begins by outlining some of the theoretical debates associated with the definition, diagnosis and prevalence of ASD. The empirical component underpinning this work uses logistic modelling to ascertain whether the proportion of children with a statement of special educational need (SEN) for ASD is different for Asian and for White children and whether the proportion of children with a statement of SEN for ASD varies between LEAs. The discussion speculates as to possible reasons for the differences found and identifies areas for further research.     

Role of jasmonic acid in improving tolerance of rapeseed (<Emphasis Type="Italic">Brassica napus</Emphasis> L.) to Cd toxicity

The well-known detrimental effects of cadmium (Cd) on plants are chloroplast destruction, photosynthetic pigment inhibition, imbalance of essential plant nutrients, and membrane damage. Jasmonic acid (JA) is an alleviator against different stresses such as salinity and drought. However, the functional attributes of JA in plants such as the interactive effects of JA application and Cd on rapeseed in response to heavy metal stress remain unclear. JA at 50 μmol/L was observed in literature to have senescence effects in plants. In the present study, 25 μmol/L JA is observed to be a “stress ameliorating molecule” by improving the tolerance of rapeseed plants to Cd toxicity. JA reduces the Cd uptake in the leaves, thereby reducing membrane damage and malondialdehyde content and increasing the essential nutrient uptake. Furthermore, JA shields the chloroplast against the damaging effects of Cd, thereby increasing gas exchange and photosynthetic pigments. Moreover, JA modulates the antioxidant enzyme activity to strengthen the internal defense system. Our results demonstrate the function of JA in alleviating Cd toxicity and its underlying mechanism. Moreover, JA attenuates the damage of Cd to plants. This study enriches our knowledge regarding the use of and protection provided by JA in Cd stress.     

What do they like? Communication preferences and patterns of older adults in the United States: The role of technology

ABSTRACT

With the development of information and communication technologies (ICTs), there are increasingly more Internet-based communication methods available for older adults besides traditional methods (e.g., in-person or landline phone). However, older adults’ preferred communication methods remain under-investigated. The purpose of this study is to explore the communication preferences and patterns of older adults in the United States, with emphasis on technologically-mediated environments. In this study, 17 semistructured interviews were conducted with participants from a midwestern state in the United States. The goal was to examine older adults’ communication patterns and preferences with family members and friends, as well as their views about the impacts of modern technology on communication. Three themes (communication preferences and reasons, communication barriers, and the impacts of technology) were generated from the interviews. The findings showed that although face-to-face communication is the most preferred method, telephone communication is the most commonly adopted method. Interviewees also shared different opinions regarding Internet-based communication. The current study illustrated the importance of understanding the preferences and patterns of older adults’ communication needs and desires.     

Recent Western Reflections on Islamic Education

This book review will examine and evaluate a number of books with regards to Muslim Education in the contemporary Western world. It will look at how the various books highlight and deal with (1) the growing awareness of the impact of Islamic education as an integral part of a young European Muslim's identity and its affect on the local and the larger community and (2) the necessity to try to engage with a new definition of Islamic education and its practice outside the traditional Muslim world.     

Addressing computational estimation in the Kuwaiti curriculum: teachers’ views

Computational estimation has not yet established a place in the Kuwaiti national curriculum. An attempt was made to include it during the early 1990s, but it was dropped by the Kuwaiti Ministry of Education because of the difficulties teachers had teaching it. In an effort to provide guidance for reintroducing the concept into the curriculum, this study reports on mathematics teachers’ understanding of the meaning of computational estimation and their views about its significance in the elementary and middle school curricula in Kuwait. Data gathered from 59 elementary and middle schools teachers in Kuwait revealed that more than 60% of teachers equate computational estimation with rounding. While two-thirds of the teachers viewed computational estimation to be an important skill for daily life; only one-fifth (20%) saw it as important in mathematics education. More than half of the teachers either disagreed with the idea of teaching computational estimation or only wanted to teach it in limited situations. Most were concerned about the difficulty of learning computational estimation or feared that teaching computational estimation would cause problems with students’ development of standard algorithms for determining an exact answer. These findings reveal the challenge that mathematics educators face in introducing computational estimation into the mathematics curriculum. In order for computational estimation to be taught in elementary and middle school classrooms, teachers need to understand the concept and its value in education. Teacher education needs to focus on helping teachers better understand the concept of computational estimation and appreciate its value for instruction.     

Quantitation of endogenous inhibitor of milli-CANP in Duchenne muscular dystrophy platelets and lymphocytes: Its implication in regulation

With a view to gain an insight into the regulation of calcium activated neutral protease by its endogenous inhibitor, the inhibitor was quantitated in platelets and lymphocytes of Duchenne muscular dystrophy patients and controls by dot immunoblot procedure using polyclonal antibodies against the inhibitor. A two fold increase in inhibitor levels was observed in lymphocytes but no significant increase in inhibitor levels in platelets from Duchenne muscular dystrophy. These results suggest that different regulatory mechanisms of modulation of CANP operate in these two cell types in Duchenne muscular dystrophy.     

The T-class of time-frequency distributions: Time-only kernels with amplitude estimation

This paper presents a class of time-frequency distributions (TFDs) characterized by time-lag kernels which are functions of time only. If the parameters of the time-only kernels are properly chosen, their corresponding TFDs, the T-distributions, are more efficient than their two-dimensional counterparts in terms of cross-terms suppression while keeping a high-energy concentration (resolution) around the IF law of non-stationary signals. The proposed class is a subclass of Cohen's Class of quadratic TFDs. We have shown that separable time-lag kernels should be lag-independent (or time-only) for best resolution. In addition, non-parametric amplitude estimation is possible directly from the T-distributions in case of FM signals, a property that is not verified by other TFDs. Two examples of the T-distributions are given and their performance is compared to other TFDs with numerical examples using synthetic and real-life signals.