Five-quark components in baryons

Evidence has been accumulating for the existence of significant intrinsic non-perturbative five-quark components in various baryons. The inclusion of the five-quark components gives a natural explanation of the excess of $\bar d$ over $\bar u$, significant quark orbital angular momentum in the proton, the problematic mass and decay pattern of the lowest $1/2^-$ baryon nonet, etc.. A breathing mode of $qqq\leftrightarrow qqqq\bar q$ is suggested for the lowest $1/2^-$ baryon octet. Evidence of a predicted member of the new scheme, $\Sigma^*(1/2^-)$ around 1380 MeV, is introduced.Comment: invited plenary talk at the 10th International Conference on Hypernuclear and Strange Particle Physics (HypX09) September 14th - 18th, 2009, Tokai, Ibaraki, Japa

From Rags to Riches: Assessing poverty and vulnerability in urban Nepal

Urbanisation brings with it rapid socio-economic change with volatile livelihoods and unstable ownership of assets. Yet, current measures of wealth are based predominantly on static livelihoods found in rural areas. We sought to assess the extent to which seven common measures of wealth appropriately capture vulnerability to poverty in urban areas. We then sought to develop a measure that captures the characteristics of one urban area in Nepal. We collected and analysed data from 1,180 households collected during a survey conducted between November 2017 and January 2018 and designed to be representative of the Kathmandu valley. A separate survey of a sub set of households was conducted using participatory qualitative methods in slum and non-slum neighbourhoods. A series of currently used indices of deprivation were calculated from questionnaire data. We used bivariate statistical methods to examine the association between each index and identify characteristics of poor and non-poor. Qualitative data was used to identify characteristics of poverty from the perspective of urban poor communities which were used to construct an Urban Poverty Index that combined asset and consumption focused context specific measures of poverty that could be proxied by easily measured indicators as assessed through multivariate modelling. We found a strong but not perfect association between each measure of poverty. There was disagreement when comparing the consumption and deprivation index on the classification of 19% of the sample. Choice of short-term monetary and longer-term capital approaches accounted for much of the difference. Those who reported migrating due to economic necessity were most likely to be categorised as poor. A combined index was developed to capture these dimension of poverty and understand urban vulnerability. A second version of the index was constructed that can be computed using a smaller range of variables to identify those in poverty. Current measures may hide important aspects of urban poverty. Those who migrate out of economic necessity are particularly vulnerable. A composite index of socioeconomic status helps to capture the complex nature of economic vulnerability

Anisotropic Structure of the Order Parameter in FeSe0.45Te0.55 Revealed by Angle Resolved Specific Heat

The symmetry and structure of the superconducting gap in the Fe-based superconductors are the central issue for understanding these novel materials. So far the experimental data and theoretical models have been highly controversial. Some experiments favor two or more constant or nearly-constant gaps, others indicate strong anisotropy and yet others suggest gap zeros ("nodes"). Theoretical models also vary, suggesting that the absence or presence of the nodes depends quantitatively on the model parameters. An opinion that has gained substantial currency is that the gap structure, unlike all other known superconductors, including cuprates, may be different in different compounds within the same family. A unique method for addressing this issue, one of the very few methods that are bulk and angle-resolved, calls for measuring the electronic specific heat in a rotating magnetic field, as a function of field orientation with respect to the crystallographic axes. In this Communication we present the first such measurement for an Fe-based high-Tc superconductor (FeBSC). We observed a fourfold oscillation of the specific heat as a function of the in-plane magnetic field direction, which allowed us to identify the locations of the gap minima (or nodes) on the Fermi surface. Our results are consistent with the expectations of an extended s-wave model with a significant gap anisotropy on the electron pockets and the gap minima along the \Gamma M (or Fe-Fe bond) direction.Comment: 32 pages, 7 figure

Gas-cushioned droplet impacts with a thin layer of porous media

The authors are grateful to Dr. Manish Tiwari for introducing them to experiments involving droplet impacts with textured substrates. PDH is grateful for the use of the Maxwell High-Performance Computing Cluster of the University of Aberdeen IT Service. RP is grateful for the use of the High-Performance Computing Cluster supported by the Research and Specialist Computing Support service at the University of East Anglia.Peer reviewedPostprin

Antiferromagnetic Correlation and the Pairing Mechanism of the Cuprates and Iron Pnictides : a View From the Functional Renormalization Group Studies

We compare the one-loop functional renormalization group results for the cuprates and the iron pnictides. Interestingly a coherent picture suggesting that antiferromagnetic correlation causes pairing for both materials emerges.Comment: 4 pages, 5 figures. Proposal for detecting out of phase s-wave pairing symmetry via STM is adde

Scanning SQUID microscopy on polycrystalline SmFeAsO_{0.85} and NdFeAsO_{0.94}F_{0.06}

The order parameter of the recently-discovered ferric arsenide family of superconductors remains uncertain. Some early experiments on polycrystalline samples suggested line nodes in the order parameter, however later experiments on single crystals have strongly supported fully-gapped superconductivity. An absence of nodes does not rule out unconventional order: {pi} phase shifts between the separate Fermi sheets and time-reversal symmetry-breaking components in the order parameter remain possibilities. One test for unconventional order is scanning magnetic microscopy on well-coupled polycrystalline samples: d- or p-wave order would result in orbital frustration, leading to spontaneous currents and magnetization in the superconducting state. We have performed scanning SQUID microscopy on SmFeAsO{sub 0.85} and NdFeAsO{sub 0.94}F{sub 0.06}, and in neither material do we find spontaneous orbital currents, ruling out p- or d-wave order

Limits on the Superconducting Order Parameter in NdFeAsO_{1-x}F_y from Scanning SQUID Microscopy

Identifying the symmetry of the superconducting order parameter in the recently-discovered ferrooxypnictide family of superconductors, RFeAsO{sub 1-x}F{sub y}, where R is a rare earth, is a high priority. Many of the proposed order parameters have internal {pi} phase shifts, like the d-wave order found in the cuprates, which would result in direction-dependent phase shifts in tunneling. In dense polycrystalline samples, these phase shifts in turn would result in spontaneous orbital currents and magnetization in the superconducting state. We perform scanning SQUID microscopy on a dense polycrystalline sample of NdFeAsO{sub 0.94}F{sub 0.06} with T{sub c} = 48K and find no such spontaneous currents, ruling out many of the proposed order parameters

Recycling oriented vertical vibratory separation of copper and polypropylene particles

Vibration has been employed in various engineering processes for material handling. The famous Brazil nut effect, large particles tend to rise to the top under vibration, initiates various research about vibration induced particle segregation. Particle size and density are two determining factors for their behaviour under vibration. Previous research in University of Nottingham proves vertical vibratory separation to be a promising environmental friendly mechanical separation method for recycling metallic fraction from shredded Waste Electric and Electronic Equipment (WEEE) stream. A pilot scale thin cell vibratory separator has been developed to investigate the potential for WEEE recycling applications. Shredded copper and polypropylene particles have been chosen to mimic metallic and non-metallic fractions in WEEE. Vibratory separation experiment with controlled environment and addition of solid lubricant are presented in this paper. The result demonstrates the effect of relative humidity and solid lubricant on improving flowability of granular system hence successful vibratory separation. The proposed mechanisms for the presence of moisture and solid lubricant are lubricant effect and elimination of static electricity