645 research outputs found
Correspondence between HBT radii and the emission zone in non-central heavy ion collisions
In non-central collisions between ultra-relativistic heavy ions, the
freeze-out distribution is anisotropic, and its major longitudinal axis may be
tilted away from the beam direction. The shape and orientation of this
distribution are particularly interesting, as they provide a snapshot of the
evolving source and reflect the space-time aspect of anisotropic flow.
Experimentally, this information is extracted by measuring pion HBT radii as a
function of angle with respect to the reaction plane. Existing formulae
relating the oscillations of the radii and the freezeout anisotropy are in
principle only valid for Gaussian sources with no collective flow. With a
realistic transport model of the collision, which generates flow and
non-Gaussian sources, we find that these formulae approximately reflect the
anisotropy of the freezeout distribution.Comment: 9 pages, 8 figure
Observable implications of geometrical and dynamical aspects of freeze-out in heavy ion collisions
Using an analytical parameterization of hadronic freeze-out in relativistic
heavy ion collisions, we present a detailed study of the connections between
features of the freeze-out configuration and physical observables. We focus
especially on anisotropic freeze-out configurations (expected in general for
collisions at finite impact parameter), azimuthally-sensitive HBT
interferometry, and final-state interactions between non-identical particles.
Model calculations are compared with data taken in the first year of running at
RHIC; while not perfect, good agreement is found, raising the hope that a
consistent understanding of the full freeze-out scenario at RHIC is possible,
an important first step towards understanding the physics of the system prior
to freeze-out.Comment: 36 pages, 56 figures, 2 tables; version accepted for publication in
PRC: some figures, references and discussion added; now also discusses
classical versus quantum statistic
Deterioration of muscle force and contractile characteristics are early pathological events in spinal and bulbar muscular atrophy mice
Spinal and bulbar muscular atrophy (SBMA), also known as Kennedy's Disease, is a late-onset, X-linked, progressive neuromuscular disease, which predominantly affects males. The pathological hallmarks of the disease are defined by selective loss of spinal and bulbar motor neurons, accompanied by weakness, atrophy and fasciculations of bulbar and limb muscles. SBMA is caused by a CAG repeat expansion in the gene that encodes the androgen receptor (AR) protein. Disease manifestation is androgen dependent and results principally from a toxic gain of AR function. There are currently no effective treatments for this debilitating disease. It is important to understand the course of the disease in order to target therapeutics to key pathological stages. This is especially relevant in disorders such as SBMA, where disease can be identified prior to symptom onset, through family history and genetic testing. To fully characterise the role of muscle in SBMA, we undertook a longitudinal physiological and histological characterisation of disease progression in the AR100 mouse model of SBMA. Our results show that the disease first manifests in skeletal muscle, prior to any motor neuron degeneration, which only occurs in late stage disease. These findings reveal alterations in muscle function, including reduced muscle force and changes in contractile characteristics, are early pathological events in SBMA mice and suggest that muscle-targeted therapeutics may be effective in SBMA
Exploring Perceptions of Customer Value: The Role of Corporate Social Responsibility Initiatives in the European Telecommunications Industry
Purpose - This paper develops a framework that describes and explains how corporate social
responsibility (CSR) initiatives are perceived by customers and links customer perception to
the notion of customer value perception. In order to explore customer value conception
firstly, the perception of CSR initiatives is investigated; secondly, indications for the value
enhancing effects of CSR initiatives are studied, and finally, the varying effects which
different value categories can have on customer attitudes and behaviour are extracted.
Design/methodology/approach - The data consists of twelve semi-structured interviews
with customers of European telecommunication companies.
Findings - The results suggest that CSR initiatives, when communicated efficiently and
considered as relevant by customers, will in the main enhance two customer value categories:
(1) the extrinsic self-oriented value defined as efficiency and excellence and (2) the intrinsic
other-oriented value pertaining to ethics or spirituality. Enhancement of extrinsic selforiented
value imbeds the potential of CSR initiatives to affect customers’ purchase
behaviour and thus strengthen ethical consumerism within the telecommunications industry.
Research limitations/implications – The main implication for research is a better
understanding of the relationship between customer perception and customer value
perception in the field of ethical consumerism. Focusing on one industry for the study can be
named as a limitation.
Practical implications – As indicated by the research results by customers prioritised CSR
initiative can affect the customer value perception, mainly the extrinsic/self-oriented value. If
the company is aiming to change customer behaviour and to strengthen ethical consumerism,
it is important that the customer experience of CSR initiatives improve excellence (quality)
and/or efficiency of the product/service.
Originality/value – This paper fulfils an identified need of research on how CSR initiatives
can influence consumer behaviour
Application of a value chain approach to understanding white kenkey production, vending and consumption practices in three districts of Ghana
Traditional processing and street vending of foods is a vital activity in the informal sector of the Ghanaian economy and offers livelihood for a large number of traditional food processors. Kenkey is a fermented maize ‘dumpling’ produced by traditional food processors in Ghana. Ga and Fante kenkey have received research attention and there is a lot of scientific information on kenkey production. White kenkey produced from dehulled maize grains is a less known kind of kenkey. A survey was held in three districts of Ghana to study production, vending and consumption of white kenkey and to identify major bottlenecks related to production, which can be addressed in studies to re-package kenkey for a wider market. Questionnaires were designed for producers, vendors and consumers of white kenkey to collate information on Socio-cultural data, processing technologies, frequency of production and consumption, product shelf life, reasons for consumption and quality attributes important to consumers using proportional sampling. The survey was conducted in white kenkey production zones and trade centers. Results showed that production of white kenkey is done on small-scale levels by middle-aged women in households with 10-50 kg of dehulled maize processed into white kenkey, 1-3 times weekly. A third (28%) of the women processed up to 50-100 kg of maize per week. Although 62% of vendors sell 50-100 balls of white kenkey daily, 15% of them sell more than 170 balls. Majority of consumers (45.9%) liked white kenkey because of its convenience (ready-to-eat). Texture and taste were quality attributes desired by kenkey consumers. Producers did not have written records of process controls and product throughputs. Inspite of their cottage nature, production of white kenkey is a profitable employment for producers and vendors and is popular among consumers. Product improvement, process and product characteristics could offer scale-up criteria for development of white kenkey production using standardized procedures for steeping times, steeping temperature and fermentation times.Keywords: maize, white kenkey, value chain, traditional, product development, re-engineerin
Volatile compounds of maari, a fermented product from baobab (Adansonia digitata L.) seeds
The volatile compounds associated with baobab seeds fermentation for Maari production were extracted and analysed by Likens-Nickerson simultaneous steam distillation-extraction method and gas chromatography-mass spectrometry (GC-MS), respectively. Furthermore, the titratable acidity, tannin content and proximate composition were evaluated. A total of 96 compounds were identified with esters, acids, alcohols and ketones being quantitatively the major groups. Fermentation led to an increase in the concentration of total volatile compounds from 121.6 in unfermented cooked seeds to 809.1 mg kg-1 in the fermented product. Drying resulted in a significant loss of up to 80.7% of the total volatiles.Key words: Volatile compounds, maari, baobab, fermentation
A Biochemical Genomics Screen for Substrates of Ste20p Kinase Enables the In Silico Prediction of Novel Substrates
The Ste20/PAK family is involved in many cellular processes, including the regulation of actin-based cytoskeletal dynamics and the activation of MAPK signaling pathways. Despite its numerous roles, few of its substrates have been identified. To better characterize the roles of the yeast Ste20p kinase, we developed an in vitro biochemical genomics screen to identify its substrates. When applied to 539 purified yeast proteins, the screen reported 14 targets of Ste20p phosphorylation. We used the data resulting from our screen to build an in silico predictor to identify Ste20p substrates on a proteome-wide basis. Since kinase-substrate specificity is often mediated by additional binding events at sites distal to the phosphorylation site, the predictor uses the presence/absence of multiple sequence motifs to evaluate potential substrates. Statistical validation estimates a threefold improvement in substrate recovery over random predictions, despite the lack of a single dominant motif that can characterize Ste20p phosphorylation. The set of predicted substrates significantly overrepresents elements of the genetic and physical interaction networks surrounding Ste20p, suggesting that some of the predicted substrates are in vivo targets. We validated this combined experimental and computational approach for identifying kinase substrates by confirming the in vitro phosphorylation of polarisome components Bni1p and Bud6p, thus suggesting a mechanism by which Ste20p effects polarized growth
Cross-Country Comparisons of Covid-19: Policy, Politics and the Price of Life
This is the final version. Available on open access from Springer via the DOI in this recordCoronavirus has claimed the lives of over half a million people world-wide and this death toll
continues to rise rapidly each day. In the absence of a vaccine, non-clinical preventative
measures have been implemented as the principal means of limiting deaths. However, these
measures have caused unprecedented disruption to daily lives and economic activity. Given
this developing crisis, the potential for a second wave of infections and the near certainty of
future pandemics, lessons need to be rapidly gleaned from the available data. We address the
challenges of cross-country comparisons by allowing for differences in reporting and
variation in underlying socio-economic conditions between countries. Our analyses show
that, to date, differences in policy interventions have out-weighed socio-economic variation
in explaining the range of death rates observed in the data. Our epidemiological models show
that across 8 countries a further week long delay in imposing lockdown would likely have
cost more than half a million lives. Furthermore, those countries which acted more promptly
saved substantially more lives than those that delayed. Linking decisions over the timing of
lockdown and consequent deaths to economic data, we reveal the costs that national
governments were implicitly prepared to pay to protect their citizens as reflected in the
economic activity foregone to save lives. These ‘price of life’ estimates vary enormously
between countries, ranging from as low as around 1million (e.g. Denmark, Germany, New Zealand and Korea). The lowest estimates
are further reduced once we correct for under-reporting of Covid-19 deaths
Finding hidden knowledge in WASH: effective methods for exploring the needs of perimenopausal women in Ghana
As increased urbanisation brings the challenges of providing sustainable
and equitable WASH provision for all, a globally ageing population will bring more women in low income countries passing through the perimenopause, the transition to menopause , with various hidden WASH
needs. A lack of knowledge upon these needs also means that effective methods to work with perimenopausal women
are not well established. Drawing on field experiences from Accra and Kumasi in Ghana, this paper reflects upon the methodological lessons learned in researching the WASH needs of perimenopausal women in two low income communities. An effective methodology to explore perimenopausal women’s WASH needs encourages participation
and engagement with the topic through use of appropriate tools , and effective
community mobilisation. A collaboration of different people in a team, group reflection and adaptation of tools which consider practical aspects and local cultural values
are needed to understand such needs
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