Water supply of Rolla, Missouri

An essential feature of a prospering town is a system of water supply, to protect property from losses by fire and to furnish water for domestic use. Rolla, a town of about fifteen hundred inhabitants, is without a proper water supply, in consequence of which it has suffered many losses to property, which could have been averted, or at least diminished, had the proper protection been at hand. At present the only fire protection the business part of town has, is derived from one large cistern placed on the principal street, while the protection for the residence portion, is derived from private cicterns sic. The quantity of water in these cisterns is dependant sic on the amount of rainfall, which in this region is very uncertain; therefore, when there is the greatest demand for water in these cisterns, the quantity may be insufficient to meet the necessary requirements. Hence the reason for selecting this subject for our thesis --page 3

Causal Consistency of Structural Equation Models

Complex systems can be modelled at various levels of detail. Ideally, causal models of the same system should be consistent with one another in the sense that they agree in their predictions of the effects of interventions. We formalise this notion of consistency in the case of Structural Equation Models (SEMs) by introducing exact transformations between SEMs. This provides a general language to consider, for instance, the different levels of description in the following three scenarios: (a) models with large numbers of variables versus models in which the `irrelevant' or unobservable variables have been marginalised out; (b) micro-level models versus macro-level models in which the macro-variables are aggregate features of the micro-variables; (c) dynamical time series models versus models of their stationary behaviour. Our analysis stresses the importance of well specified interventions in the causal modelling process and sheds light on the interpretation of cyclic SEMs.Comment: equal contribution between Rubenstein and Weichwald; accepted manuscrip

Leveraging Diffusion-Based Image Variations for Robust Training on Poisoned Data

Backdoor attacks pose a serious security threat for training neural networks as they surreptitiously introduce hidden functionalities into a model. Such backdoors remain silent during inference on clean inputs, evading detection due to inconspicuous behavior. However, once a specific trigger pattern appears in the input data, the backdoor activates, causing the model to execute its concealed function. Detecting such poisoned samples within vast datasets is virtually impossible through manual inspection. To address this challenge, we propose a novel approach that enables model training on potentially poisoned datasets by utilizing the power of recent diffusion models. Specifically, we create synthetic variations of all training samples, leveraging the inherent resilience of diffusion models to potential trigger patterns in the data. By combining this generative approach with knowledge distillation, we produce student models that maintain their general performance on the task while exhibiting robust resistance to backdoor triggers.Comment: 11 pages, 3 tables, 2 figure

Heterobimetallic conducting polymers based on salophen complexes via electrosynthesis

In this work, we report the first electrochemical synthesis of two copolymeric bimetallic conducting polymers by a simple anodic electropolymerization method. The adopted precursors are electroactive transition metal (M = Ni, Cu and Fe) salophen complexes, which can be easily obtained by direct chemical synthesis. The resulting films, labeled poly-NiCu and poly-CuFe, were characterized by cyclic voltammetry in both organic and aqueous media, attenuated total reflectance Fourier transform infrared spectroscopy, UV-vis spectroscopy, scanning electron microscopy, and coupled energy dispersive X-ray spectroscopy. The films are conductive and exhibit great electrochemical stability in both organic and aqueous media (resistant over 100 cycles without significant loss in current response or changes in electrochemical behavior), which makes them good candidates for an array of potential applications. Electrochemical detection of ascorbic acid was performed using both materials

Dinuclear Tb and Dy complexes supported by hybrid Schiff-base/calixarene ligands: synthesis, structures and magnetic properties

The synthesis of the new lanthanide complexes [HNEt$_{3}$][Dy$_{2}$(HL$^{1}$)(L$^{1}$)] (5), and [Ln$_{2}$(L$_{2}$)$_{2}$] (Ln = Tb$^{III}$ (7), Dy$^{III}$ (8)) supported by the hybrid Schiff-base/calix[4]arene ligands H$_{4}$L$^{1}$ (25-[2-((2-methylphenol)imino)ethoxy]-26,27,28-trihydroxy-calix[4]arene) and H$_{3}$L$^{2}$ (25-[2-((2-methylpyridine)imino)ethoxy]-26,27,28-trihydroxy-calix[4]arene) are reported. Spectroscopic data (for 5) and X-ray crystallographic analysis (for 7·4MeCN, 8·4MeCN) reveal the presence of dimeric structures, featuring doubly-bridged NO$_{4}$Ln(μ-O)$_{2}$LnO$_{4}$N (5) or N$_{2}$O$_{3}$Ln(μ-O)$_{2}$LnO$_{3}$N$_{2}$ cores (7, 8) with seven-coordinated Ln$^{3+}$ ions. The magnetic properties of polycrystalline samples of 5, 7 and 8 were studied by variable temperature dc and ac magnetic susceptibility measurements. The χ′′(T) vs. T plots show no maxima in zero field, but the maxima can be detected under a 3 kOe dc field. The relaxation times τ obey the Arrhenius law above 5 K. Anisotropy barriers of ∼18 cm$^{-1}$ (26 K) for 5 and ∼23 cm$^{-1}$ (33 K) for 8 were determined