Naresuan University Journal
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Understanding the Neutron Star Population with the SKA
No full textSince their discovery in the late 1960's the population of known neutron stars (NSs) has grown to 2500. The last five decades of observations have yielded many surprises and demonstrated that the observational properties of NSs are remarkably diverse. The surveys that will be performed with SKA (the Square Kilometre Array) will produce a further tenfold increase in the number of Galactic NSs known. Moreover, the SKA's broad spectral coverage, sub-arraying and multi-beaming capabilities will allow us to characterise these sources with unprecedented efficiency, in turn enabling a giant leap in the understanding of their properties. Here we review the NS population and outline our strategies for studying each of the growing number of diverse classes that are populating the "NS zoo". Some of the main scientific questions that will be addressed by the much larger statistical samples and vastly improved timing efficiency provided by SKA include: (i) the spin period and spin-down rate distributions (and thus magnetic fields) at birth, and the associated information about the SNe wherein they are formed; (ii) the radio pulsar-magnetar connection; (iii) the link between normal radio pulsars, intermittent pulsars and rotating radio transients; (iv) the slowest possible spin period for a radio pulsar (revealing the conditions at the pulsar death-line); (v) proper motions of pulsars (revealing SN kick physics); (vi) the mass distribution of NSs (vii) the fastest possible spin period for a recycled pulsar (constraining magnetosphere-accretion disc interactions, gravitational wave radiation and the equation-of-state); (viii) the origin of high eccentricity millisecond pulsars (MSPs); (ix) the formation channels for recently identified triple systems; and finally (x) how isolated MSPs are formed. We expect that the SKA will break new ground unveiling exotic systems that will challenge... [abridged
Material data matter - Standard data format for engineering materials
No full textStandardisation is often linked to the very existence of an industry and its evolutionary dynamics especially in sectors where activities are particularly reliant on network economies. This paper investigates the interests of the stakeholders of the materials industry in the effort of setting the basis for standard-compliant formats for engineering materials test data used in materials test certificates (TCs). Test certificates provide a guarantee of origin, characteristics and materials specifications. A transition to standardised electronic-test certificates (E-TCs) is thought to offer advantages over the static alternatives currently in use. This work highlights that the stakeholders involved in the process have a general need for a standard compliant data model yet their particular interests might not be completely aligned. The choice of an open, non-proprietary, data format and compatibility of the standard with legacy technological solutions prove to be critical for the implementation of standardised E-TCs
Brokering fraud and fraudulent brokers: the intersections of licit and illicit relations in the food system
No full textThis paper draws upon current research being undertaken on the risks of food fraud by adulteration to the UK’s food system. Food fraud is committed when food is deliberately placed on the market, for financial gain, with the intention of deceiving the consumer, but little is known about how, why and under which conditions such food frauds are organised, or about how motivated offenders (legitimate actors in the supply chain) ‘make the most of’ the opportunities that arise at particular times and in particular places. This paper analyses the role of brokers as key ‘nodes’ in the social/criminal networks of those actors cooperating in the commission of food fraud. In food supply chains, brokers are an essential part of ensuring that the chain is efficient in its operation. An analysis of various food adulteration cases suggests that brokers may also have a critical role in the success of food fraud by ensuring that the introduction of adulterated foodstuffs into the supply chain happens undetected. This paper explores the role of brokers, their interactions with criminal actors (licit and illicit) and their modus operandi in the crime commission process including their use of deception and their abuse of the trust central to their occupational positions for economic gain
Competition for resources can explain patterns of social and individual learning in nature
No full textIn nature, animals often ignore socially available information despite the multiple theoretical benefits of social learning over individual trial-and-error learning. Using information filtered by others is quicker, more efficient and less risky than randomly sampling the environment. To explain the mix of social and individual learning used by animals in nature, most models penalize the quality of socially derived information as either out of date, of poor fidelity or costly to acquire. Competition for limited resources, a fundamental evolutionary force, provides a compelling, yet hitherto overlooked, explanation for the evolution of mixed-learning strategies. We present a novel model of social learning that incorporates competition and demonstrates that (i) social learning is favoured when competition is weak, but (ii) if competition is strong social learning is favoured only when resource quality is highly variable and there is low environmental turnover. The frequency of social learning in our model always evolves until it reduces the mean foraging success of the population. The results of our model are consistent with empirical studies showing that individuals rely less on social information where resources vary little in quality and where there is high within-patch competition. Our model provides a framework for understanding the evolution of social learning, a prerequisite for human cumulative culture.</p
Characterisation of THP-1 macrophages as an in vitro model for CD44-targeted therapies
No full textCD44 is the major cell surface receptor of hyaluronic acid (HA) and mediates the response of cells to their cellular microenvironment. Whereas the standard isoform (CD44s) is ubiquitously expressed throughout the body, variant isoforms (CD44v) are aberrantly overexpressed in certain tumours and integrate signaling in (pre)metastatic niches, thus CD44 has become a potential target for cancer chemotherapy. However, CD44 is also one of the most abundantly expressed macrophage receptors, rendering this cellular type a competitor for the uptake of targeted nanocarriers in vivo. In this study, we have established an in vitro human macrophage model, which would allow the off-targeting effects to be determined. In particular, we have developed a standard procedure for THP-1 (human monocytic leukaemia cell line) monocyte-to-macrophage differentiation by using phorbol 12-myristate 13-acetate (PMA), characterising the resulting phenotype. The successfully differentiated THP-1 monocytes showed a significantly increased expression of CD44, which was compared in terms of a) amount and isoform composition, b) internalisation kinetics of CD44-binding nanoparticles to that of a tumoural cell line (HT-29)
Pain in multiple system atrophy and progressive supranuclear palsy compared to Parkinson's disease.
No full textBACKGROUND: Pain is a common nonmotor symptom in Parkinson's disease (PD). The pathophysiology of pain in PD is not well understood. Pain characteristics have rarely been studied in atypical parkinsonian disorders such as Multiple System Atrophy (MSA) and Progressive Supranuclear Palsy (PSP). AIM OF THE STUDY: We aimed to evaluate pain intensity, location, and associated symptoms in atypical parkinsonian disorders compared to PD. METHODS: Twenty-one patients with MSA, 16 patients with PSP, and 65 patients with PD were screened for pain using question 1.9 of the MDS-UPDRS. Pain intensity was quantified using the short form McGill Pain Questionnaire (SFMPQ). Pain locations were documented. Motor disability was measured using UPDRS-III. Affective symptoms were assessed using the Hospital Anxiety and Depression Scale (HADS). RESULTS: Pain was significantly more common and more severe in PD and MSA compared to PSP (P <0.01). Pain locations were similar with limb pain being the most common followed by neck and back pain. Pain intensity correlated with HADS scores but not motor severity. CONCLUSIONS: Pain is more common and more intense in PD and MSA than PSP. Differences in distribution of neurodegenerative pathologies may underlie these differential pain profiles
A Comparison of Signal Processing Tools:Higher Order Spectra Versus Higher Order Coherences
No full textA class of signal processing tools, Higher Order Spectra (HOS) and their normalised amplitudes Higher Order Coherences (HOC) have been receiving attentions in numerous applications, including Health Monitoring (HM) techniques for structures and machines. It is however difficult to decide which of the tools (HOS or HOC) gives the best diagnostic features. In this paper,HOSand HOCs have been compared using numerically simulated signals with and without noise. The Cross-power Spectral Density (CSD) between two signals and its ordinary coherence are also compared. The results and observations on the different spectra and their coherences are discussed here. It is observed that the use of the HOS may be more advantageous over the HOC analysis
