225 research outputs found
Deformation effects in the Si+C and Si+Si reaction Search
The possible occurence of highly deformed configurations is investigated in
the Ca and Ni di-nuclear systems as formed in the
Si+C,Si reactions by using the properties of emitted light
charged particles. Inclusive as well as exclusive data of the heavy fragments
and their associated light charged particles have been collected by using the
{\sc ICARE} charged particle multidetector array. The data are analysed by
Monte Carlo CASCADE statistical-model calculations using a consistent set of
parameters with spin-dependent level densities. Significant deformation effects
at high spin are observed as well as an unexpected large Be cluster
emission of a binary nature.Comment: 3 pages latex, 2 eps figures, paper presented in "wokshop on physics
with multidetector array (pmda2000)Calcutta, India (to be published at
PRAMANA, journal of Physics, India
The role of functional single nucleotide polymorphisms of the human glucocorticoid receptor gene NR3C1 in Polish patients with bronchial asthma
N363S and ER22/23EK polymorphisms observed within glucocorticoid receptor gene (NR3C1) may play an important role in the development of bronchial asthma. NR3C1 gene is associated with an altered sensitivity to GCs. The aim of the research project was to study the correlation between this NR3C1 gene polymorphisms and occurrence of asthma in the population of Polish asthmatics. Peripheral blood was obtained from 207 healthy volunteers and 221 asthma patients. Genotyping was carried out with PCR-RFLP method. In the groups of patients with uncontrolled moderate asthma and uncontrolled severe disease, the genotype distribution for the investigated polymorphisms was as follows: N363S-AA, AG, GG occurring with 0.881/0.073/0.046 frequency and ER22/23EK-GG, GA, AA occurring with 0.963/0.037/0.000 frequency. Chi-square analysis revealed a significantly different (P < 0.05) distribution between cases and controls for the N363S polymorphisms. The N363S polymorphism of NR3C1 gene is significantly associated with bronchial asthma, susceptibility to the development of moderate to severe form of uncontrolled bronchial asthma
Parity Dependence of Nuclear Level Densities
A simple formula for the ratio of the number of odd- and even-parity states
as a function of temperature is derived. This formula is used to calculate the
ratio of level densities of opposite parities as a function of excitation
energy. We test the formula with quantum Monte Carlo shell model calculations
in the -shell. The formula describes well the transition from low
excitation energies where a single parity dominates to high excitations where
the two densities are equal.Comment: 14 pages, 4 eps figures included, RevTe
Spallation reactions. A successful interplay between modeling and applications
The spallation reactions are a type of nuclear reaction which occur in space
by interaction of the cosmic rays with interstellar bodies. The first
spallation reactions induced with an accelerator took place in 1947 at the
Berkeley cyclotron (University of California) with 200 MeV deuterons and 400
MeV alpha beams. They highlighted the multiple emission of neutrons and charged
particles and the production of a large number of residual nuclei far different
from the target nuclei. The same year R. Serber describes the reaction in two
steps: a first and fast one with high-energy particle emission leading to an
excited remnant nucleus, and a second one, much slower, the de-excitation of
the remnant. In 2010 IAEA organized a worskhop to present the results of the
most widely used spallation codes within a benchmark of spallation models. If
one of the goals was to understand the deficiencies, if any, in each code, one
remarkable outcome points out the overall high-quality level of some models and
so the great improvements achieved since Serber. Particle transport codes can
then rely on such spallation models to treat the reactions between a light
particle and an atomic nucleus with energies spanning from few tens of MeV up
to some GeV. An overview of the spallation reactions modeling is presented in
order to point out the incomparable contribution of models based on basic
physics to numerous applications where such reactions occur. Validations or
benchmarks, which are necessary steps in the improvement process, are also
addressed, as well as the potential future domains of development. Spallation
reactions modeling is a representative case of continuous studies aiming at
understanding a reaction mechanism and which end up in a powerful tool.Comment: 59 pages, 54 figures, Revie
Real-Time, Real World Learning—Capitalising on Mobile Technology
This chapter explores the adoption of Web 2.0 technologies to promote active learning by students and to both mediate and enhance classroom instruction. Web 2.0 refers to open source, web-enabled applications (apps) that are driven by user-manipulated and user-generated content (Kassens-Noor, 2012). These apps are often rich in user participation, have dynamic content, and harness the collective intelligence of users (Chen, Hwang, & Wang, 2012). As such, these processes create “active, context based, personalised learning experiences” (Kaldoudi, Konstantinidis, & Bamidis, 2010, p. 130) that prioritise learning ahead of teaching. By putting the learner at the centre of the education process educators can provide environments that enhance employability prospects and spark a passion for learning that, hopefully, lasts a lifetime. As such, we critique an active learning approach that makes use of technology such as mobile applications (apps), Twitter, and augmented reality to enhance students’ real world learning. Dunlap and Lowenthal (2009) argue that social media can facilitate active learning as they recreate informal, free-flowing communications that allow students and academics to connect on a more emotional level. Furthermore, their use upskills students in the technical complexities of the digital world and also the specialised discourses that are associated with online participation, suitable for real world learning and working (Fig. 16.1). Three case studies explore the benefits of Web 2.0 processes. The first details the use of Twitter chats to connect students, academics, and industry professionals via online synchronous discussions that offer a number of benefits such as encouraging concise writing from students and maintaining on-going relationships between staff, students, and industry contacts. The second details a location-based mobile app that delivers content to students when they enter a defined geographical boundary linked to an area of a sports precinct. Finally, we explore the use of augmented reality apps to enhance teaching in Human Geography and Urban Studies
Affective and Deliberative Processes in Risky Choice: Age Differences in Risk Taking in the Columbia Card Task
Nucleic acid-based fluorescent probes and their analytical potential
It is well known that nucleic acids play an essential role in living organisms because they store and transmit genetic information and use that information to direct the synthesis of proteins. However, less is known about the ability of nucleic acids to bind specific ligands and the application of oligonucleotides as molecular probes or biosensors. Oligonucleotide probes are single-stranded nucleic acid fragments that can be tailored to have high specificity and affinity for different targets including nucleic acids, proteins, small molecules, and ions. One can divide oligonucleotide-based probes into two main categories: hybridization probes that are based on the formation of complementary base-pairs, and aptamer probes that exploit selective recognition of nonnucleic acid analytes and may be compared with immunosensors. Design and construction of hybridization and aptamer probes are similar. Typically, oligonucleotide (DNA, RNA) with predefined base sequence and length is modified by covalent attachment of reporter groups (one or more fluorophores in fluorescence-based probes). The fluorescent labels act as transducers that transform biorecognition (hybridization, ligand binding) into a fluorescence signal. Fluorescent labels have several advantages, for example high sensitivity and multiple transduction approaches (fluorescence quenching or enhancement, fluorescence anisotropy, fluorescence lifetime, fluorescence resonance energy transfer (FRET), and excimer-monomer light switching). These multiple signaling options combined with the design flexibility of the recognition element (DNA, RNA, PNA, LNA) and various labeling strategies contribute to development of numerous selective and sensitive bioassays. This review covers fundamentals of the design and engineering of oligonucleotide probes, describes typical construction approaches, and discusses examples of probes used both in hybridization studies and in aptamer-based assays
Stress and breast cancer: from epidemiology to molecular biology
Stress exposure has been proposed to contribute to the etiology of breast cancer. However, the validity of this assertion and the possible mechanisms involved are not well established. Epidemiologic studies differ in their assessment of the relative contribution of stress to breast cancer risk, while physiological studies propose a clear connection but lack the knowledge of intracellular pathways involved. The present review aims to consolidate the findings from different fields of research (including epidemiology, physiology, and molecular biology) in order to present a comprehensive picture of what we know to date about the role of stress in breast cancer development
- …