1,018 research outputs found
Shadow-free multimers as extreme-performance meta-atoms
We generalize the concept of parity-time symmetric structures with the goal
to create meta-atoms exhibiting extraordinary abilities to overcome the
presumed limitations in the scattering of overall lossless particles, such as
non-zero forward scattering and the equality of scattering and extinction
powers for all lossless particles. Although the forward scattering amplitude
and the extinction cross section of our proposed meta-atoms vanish, they
scatter incident energy into other directions, with controllable
directionality. These meta-atoms possess extreme electromagnetic properties not
achievable for passive scatterers. As an example, we study meta-atoms
consisting of two or three small dipole scatters. We consider possible
microwave realizations in the form of short dipole antennas loaded by lumped
elements. The proposed meta-atom empowers extraordinary response of a
shadow-free scatterer and theoretically enables most unusual material
properties when used as a building block of an artificial medium.Comment: 14 pages, 9 Figure
Lack of association between two ACE gene polymorphisms (rs4291 and Alu I/D) and late onset Alzheimer’s disease
Alzheimer’s disease (AD) is a prevalent disorder and the most common cause of dementia in elderly populations. Genetic and environmental factors together play a role in developing late onset Alzheimer's disease (LOAD). According to the recent published papers, ACE is one of the candidate susceptibility genes for LOAD. In this study, allele and genotype frequencies for rs4291 and rs1799752 polymorphisms of ACE gene, for 100 Iranian patients, affected with AD and 100 healthy controls were compared using Chi-square test. No statistically significant differences were found in genotype and allele frequencies of rs4291 and rs1799752 polymorphisms between our LOAD patients and controls. The pair-wise haplotype analysis of rs4291 -240 A/T and rs1799752 Alu I/D polymorphisms were also performed, but no significant associations were identified.Key words: ACE, Alzheimer’s disease, Iranian, association, polymorphism
Controlling Insider Dealing Through Criminal Enforcement in China
The enforcement of the new Securities Law (SL 2020) of the People’s Republic of China (PRC) in March 2020 presents a perfect opportunity to review the criminal enforcement of insider dealing cases in China’s securities market and to provide feasible suggestions for improvement for a more coherent and streamlined insider dealing regulatory framework in the PRC.
Through analysing the previous literature on public interest theories and economic theories of regulation, this article examines the necessity to regulate insider dealing in China with criminal law to ensure fairness and avoid monopolies in its securities market. The article reviews the criminalising of severe insider dealing cases in China from the Nanking National Government in the 1920s to the inception of the securities market of the PRC in the 1990s to the present day. The investigation, prosecution, enforcement, and trial of criminal offences of insider dealing in China are thoroughly examined.
The article finds a tendency for over reliance on the investigation and the administrative judgement of the China Securities Regulatory Commission (CSRC) in criminal investigation, prosecution, and trial in the PRC.
The article is one of the first articles to critically and thoroughly analyse the criminal enforcement of insider dealing in China following the recent enforcement of China’s new Securities Law in March 2020
Feeding practices and nutritional status of infants in Morogoro Municipality, Tanzania
Breast feeding practice especially exclusive breast feeding (EBF) is a major determinant of child growth and development. In Tanzania, most women breastfeed their infants for long periods, but many introduce alternative feeding too early in life. The objective of this study was to determine factors affecting EBF and the relationship between feeding practices and the nutritional status of infants. This cross-sectional survey, using a semi-structured questionnaire, was conducted in Morogoro Municipality in Tanzania. The study involved lactating women recruited from five randomly selected health facilities. Demographic, clinical, knowledge and practices related to infant feeding as well as infant anthropometric information were collected. Infant nutritional status was assessed based on weight-for-age, height-for-age and weight- for- height. There were wide variations in knowledge and practice of breastfeeding among women. Majority (92%) of the respondents gave colostrums to infants although more than 50% did not know its benefits. Eight percent of the respondents discarded colostrums on the account that it is not good for their neonates. Only 23.1% of the respondents thought that infants should be breastfed exclusively during the first six months of infancy. Ninety–eight percent of infants < 1 month of age received breast milk only, compared with 28.5% of infants aged 2-3 months and 22.3% among those who were above 3 months of age. No child in the ≥4 months old was exclusively breastfed. Over 80% of the infants had normal weights, 13% were stunted and 8% wasted. EBF was associated with higher scores for height- for- age Z (P<0.05) and weight- for- height Z (P<0.01). Age, education level and occupation of respondents were important predictors of EBF. Overall, breast feeding practices in the study population were largely suboptimal. As a result, considerable proportions of children had poor health indicators. Thus, correct breastfeeding practices should be supported and promoted to improve the well-being of children
Analytical evaluation of atomic form factors: application to Rayleigh scattering
Atomic form factors are widely used for the characterization of targets and
specimens, from crystallography to biology. By using recent mathematical
results, here we derive an analytical expression for the atomic form factor
within the independent particle model constructed from nonrelativistic screened
hydrogenic wavefunctions. The range of validity of this analytical expression
is checked by comparing the analytically obtained form factors with the ones
obtained within the Hartee-Fock method. As an example, we apply our analytical
expression for the atomic form factor to evaluate the differential cross
section for Rayleigh scattering off neutral atoms.Comment: 7 pages, 1 figur
Relativistic total cross section and angular distribution for Rayleigh scattering by atomic hydrogen
We study the total cross section and angular distribution in Rayleigh
scattering by hydrogen atom in the ground state, within the framework of Dirac
relativistic equation and second-order perturbation theory. The relativistic
states used for the calculations are obtained by making use of the finite basis
set method and expressed in terms of B-splines and B-polynomials. We pay
particular attention to the effects that arise from higher (non-dipole) terms
in the expansion of the electron-photon interaction. It is shown that the
angular distribution of scattered photons, while it is symmetric with respect
to the scattering angle =90 within the electric dipole
approximation, becomes asymmetric when higher multipoles are taken into
account. The analytical expression of the angular distribution is parametrized
in terms of Legendre polynomials. Detailed calculations are performed for
photons in the energy range 0.5 to 10 keV. When possible, results are compared
with previous calculations.Comment: 8 pages, 5 figure
Fatigue interventions in long term, physical health conditions: A scoping review of systematic reviews.
OBJECTIVE: Fatigue is prominent across many long term physical health conditions. This scoping review aimed to map the fatigue intervention literature, to ascertain if certain interventions may be effective across conditions, and if novel interventions tested in specific long term conditions may be promising for other conditions. METHODS: Scoping review methodological frameworks were used. Electronic bibliographic databases were searched (inception to November 2016) for systematic reviews of fatigue interventions in long term conditions. Inclusion criteria were: long term physical health condition; review focus on fatigue management; objective and systematic review process; primary review outcome is fatigue. Articles focussing on surgical interventions or treatments thought to trigger fatigue were excluded. A narrative synthesis was performed. RESULTS: Of 115 full texts screened, 52 reviews were included. Interventions were categorised as pharmacological and non-pharmacological (exercise, psychological/behavioural and complementary medicine). Pharmacological interventions did not consistently demonstrate benefit, except for anti-TNFs and methylphenidate which may be effective at reducing fatigue. Non-pharmacological interventions such as graded exercise and fatigue-specific psychological interventions may be effective, but heterogeneous intervention components limit conclusions. 'Complementary medicine' interventions (e.g. Chinese herbal medicines) showed promise, but the possibility of publication bias must be considered. CONCLUSIONS: Further research is necessary to inform clinical practice. The reported effectiveness of some interventions across inflammatory health conditions, such as anti-TNFs, aerobic exercise, and psychologically based approaches such as CBT, highlights a potential transdiagnostic avenue for fatigue management. More novel strategies that may be worth exploring include expressive writing and mindfulness, although the mechanisms for these in relation to fatigue are unclear. More work is needed to identify transdiagnostic mechanisms of fatigue and to design interventions based on these
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A global view of aquaculture policy
Aquaculture is among the most dynamic sectors in the global food system, yet it remains surprisingly underrepresented in the mainstream literature on food policy. This article reviews 204 published articles and re ports and shows that government policies have strongly influenced the geographic distribution of aquaculture growth, as well as the types of species, technology, management practices, and infrastructure adopted in different locations. Global cross-section studies reveal a broad spectrum of under- to over-regulated aquaculture systems that correspond, respectively, to high- and low-growth areas for aquaculture. The bulk of this paper centers on aquaculture policy as it plays out six individual countries plus the EU: Bangladesh, Zambia, Chile, China, USA, and Norway. These case studies shed light on aquaculture policies aimed at economic development, aquaculture disease management, siting, environmental performance, and trade protection. Experiences from these countries point to the need to find the right policy balance between semi-subsistence farms, small and medium enterprises (SME), and large-scale commercial operations, particularly in low-income settings. The cases also highlight the importance of addressing aquaculture disease pressures and misuse of antimicrobials in many parts of the world, and identifying successful aquaculture policy instruments and institutions that can be transferred between countries. The review underscores the challenges of establishing nutrition-sensitive aquaculture policies and of incorporating aquaculture directly into food policy and global food system dialogues and action
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High Quality, Fully Dense Ceramic Components Manufactured Using Fused Deposition of Ceramics (FDC)
Solid Freeform Fabrication (SFF) is a technology that produces physical solid components or
parts from computer design models. This technology has the potential of reducing functional
ceramic product development cycle time in terms of reducing design iteration and production
time, minimizing extra post processing, and therefore reducing cost. A commercially available
Fused Deposition Modeling (FDM™) 3D Modeler was altered for use with ceramics. This
newly developed method referred to as Fused Deposition of Ceramics (FDC) is capable of
fabricating complex shape, functional ceramic components.
We have investigated issues related to hardware, software, feed material, and build strategy which
are required to achieve high quality, fully dense green ceramic parts. In this paper, we report
recent improvements made in the FDC process, including hardware modifications, software
improvements, feed material standardization, as well as build strategy/condition control. We also
report the current FDC status for making complex functional parts. Our goal is to optimize the
FDC condition to ensure its robustness for producing defect free green ceramic parts consistently
and without interruption.Mechanical Engineerin
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