Representation in the (Artificial) Immune System

Much of contemporary research in Artificial Immune Systems (AIS) has partitioned into either algorithmic machine learning and optimisation, or, modelling biologically plausible dynamical systems, with little overlap between. We propose that this dichotomy is somewhat to blame for the lack of significant advancement of the field in either direction and demonstrate how a simplistic interpretation of Perelson’s shape-space formalism may have largely contributed to this dichotomy. In this paper, we motivate and derive an alternative representational abstraction. To do so we consider the validity of shape-space from both the biological and machine learning perspectives. We then take steps towards formally integrating these perspectives into a coherent computational model of notions such as life-long learning, degeneracy, constructive representations and contextual recognition—rhetoric that has long inspired work in AIS, while remaining largely devoid of operational definition

Management of Patients With Crohn's Disease and Ulcerative Colitis During the Coronavirus Disease-2019 Pandemic: Results of an International Meeting

The International Organization for the Study of Inflammatory Bowel Diseases (IOIBD) is the only global organization devoted to the study of and management of the inflammatory bowel diseases (IBDs), namely, Crohn?s disease and ulcerative colitis. Membership is composed of physician-scientists who have established expertise in these diseases. The organization hosts an annual meeting and a number of working groups addressing issues of the epidemiology of IBD, diet and nutrition, and the development and use of treatments for IBD. There are currently 89 members of IOIBD representing 26 different countries. The organization has taken particular interest in the coronavirus disease-2019 (COVID-19) pandemic and how it may affect the IBD patient population. This document summarizes the results of 2 recent virtual meetings of the group and subsequent expert guidance for patients and providers

Hole distribution between the Ni 3d and O 2p orbitals in Nd2-xSrxNiO4-d

We present a joint experimental and theoretical study of x-ray absorption at the O-K and Ni-L-2.3 thresholds of Nd2-xSrxNiO4-delta providing an analysis of the distribution of doped holes induced by Sr substitution between Ni 3d and O 2p orbitals. The preedge peak in the O-K x-ray absorption (XAS) spectra, reflecting holes located in the O 2p orbitals, increases monotonically with the degree of Sr doping up to the maximum doping level studied (x=1.4). The saturation in the relative intensity of the O-K preedge peak in the analogous lanthanum nickelate reported in the literature is shown to be most likely due to surface oxygen deficiency. Furthermore, the experimental Ni-L-2.3 XAS spectrum of the Ni(III) nickelate Nd1.1ST0.9NiO3.95 was simulated by a cluster approach, including charge-transfer and complete multiplet interactions, and compared with the corresponding spectrum of the Ni(III) system Nd2Li0.5Ni0.5O4. The 3d(7) weight in the ground state of Nd1.1Sr0.9NiO3.95 was found to be 42%, somewhat smaller than the value of 51% found for Nd2Li0.5Ni0.5O4. This indicates the influence of nonlocal effects in x-ray-absorption spectroscopy, which, in this case is due to the increased covalency in the Sr-doped system as a result of inter-NiO6-cluster interaction. Such interactions are absent in Nd2Li0.5Ni0.5O4, which is characterized by having isolated NiO6 clusters

Chemical characterization of wet precipitation events and deposition of pollutants in coal mining region, India

The present study investigated the chemical composition of wet atmospheric precipitation in India’s richest coal mining belt. Total 418 samples were collected on event basis at six sites from July to October in 2003 and May to October in 2004 and analysed for pH, EC, F−, Cl−, SO2_ 4 , NO_3 , Ca2+, Mg2+, Na+, K+ and NHþ4 . The average pH value (5.7) of the rainwater of the investigated area is alkaline in nature. However, the temporal pH variation showed the alkaline nature during the early phase of monsoonal rainfall but it trends towards acidic during the late and high rainfall periods. The rainwater chemistry of the region showed high contribution of Ca2+ (47%) and NHþ4 (21%) in cations and SO24_ (55%) and Cl− (23%) in anionic abundance. The high non seas salt fraction (nss) of Ca2+ (99%) and Mg2+ (96%) suggests crustal source of the ions, while the high nss SO24_ (96%) and high SO2_ 4 _ NO_3 _ þ C1__ratio signifying the impact of anthropogenic sources and the source of the acidity. The ratio of SO2_ 4 þ NO_3 _ NHþ4 _ þ Ca2þ_varies from 0.03 to 3.23 with the average value of 0.84 suggesting that Ca2+ and NHþ4 play a major role in neutralization processes. The assessment of the wet ionic deposition rates shows no any specific trend, however Ca2+ deposition rate was highest followed by SO2_ 4 and NH4