AI in space: Past, present, and possible futures

While artificial intelligence (AI) has become increasingly present in recent space applications, new missions being planned will require even more incorporation of AI techniques. In this paper, we survey some of the progress made to date in implementing such programs, some current directions and issues, and speculate about the future of AI in space scenarios. We also provide examples of how thinkers from the realm of science fiction have envisioned AI's role in various aspects of space exploration

Coherent description of the intrinsic and extrinsic anomalous Hall effect in disordered alloys on an abab initioinitio level

A coherent description of the anomalous Hall effect (AHE) is presented that is applicable to pure as well as disordered alloy systems by treating all sources of the AHE on equal footing. This is achieved by an implementation of the Kubo-St\v{r}eda equation using the fully relativistic Korringa-Kohn-Rostoker (KKR) Green's function method in combination with the Coherent Potential Approximation (CPA) alloy theory. Applications to the pure elemental ferromagnets bcc-Fe and fcc-Ni led to results in full accordance with previous work. For the alloy systems fcc-Fe$_x$Pd$_{1-x}$ and fcc-Ni$_x$Pd$_{1-x}$ very satisfying agreement with experiment could be achieved for the anomalous Hall conductivity (AHC) over the whole range of concentration. To interpret these results an extension of the definition for the intrinsic AHC is suggested. Plotting the corresponding extrinsic AHC versus the longitudinal conductivity a linear relation is found in the dilute regimes, that allows a detailed discussion of the role of the skew and side-jump scattering processes.Comment: * shortened manuscript * slight rewordings * changed line style in Fig 1 * corrected misprinted S (skewness) factor * merged Fig. 3 with Fig. 1 * new citation introduce

Critical Charges on Strange Quark Nuggets and Other Extended Objects

We investigate the behavior of the critical charge for spontaneous pair production, $Z_C$, defined as the charge at which the total energy of a $K$-shell electron is $E=-m_e$, as a function of the radius $R$ of the charge distribution. Our approach is to solve the Dirac equation for a potential $V(r)$ consisting of a spherically symmetrical charge distribution of radius $R$ and a Coulomb tail. For a spherical shell distribution of the type usually associated with color-flavor locked strange quark nuggets, we confirm the relation $Z_C=0.71 R({\rm fm})$ for sufficiently large $R$ obtained by Madsen, who used an approach based on the Thomas-Fermi model. We also present results for a uniformly charged sphere and again find that $Z_C\sim R$ for large enough $R$. Also discussed is the behavior of $Z_C$ when simple {\it ad hoc} modifications are made to the potential for $0\leq r < R$.Comment: 7 pages, 6 figure

Antibacterial and anticancer activity of green synthesised silver nanoparticles using polysaccharides extracted from the marine alga Portieria hornemannii

The increasing incidence of cancer cases and multi-drug-resistant bacteria, which are major threats to humankind, forces the research world to innovate new molecules to deal with them.  The main aim of the present work is to prepare silver nanoparticles using macroalgal polysaccharides and to study biological activities. The silver nanoparticles (NPs) were prepared using polysaccharides extracted from the marine macro alga Portieria hornemannii by stirring them with 1 mM silver nitrate after 24 h at 90 ºC. The formed silver nanoparticles were characterized using UV-visible spectrophotometry, Fourier transform infrared spectroscopy (FTIR) analysis, Transmission Electron Microscopy (TEM) analysis, selected-area electron diffraction (SAED), and Energy Dispersive X-ray (EDX) analysis. UV-visible spectrum analysis revealed a surface plasmon peak at 380 nm, showing the development of silver nanoparticles. The nanoparticle size varied between 40 and 50 nm and the functional group was analyzed using FT-IR spectrum. The broadband was observed at 3304 cm-1 (hydroxyl and amino group) and the narrow band was observed at 2907 cm-1 (C–H stretching vibration), 1657 cm-1 (stretching of carbonyl groups), and 1001 cm-1 (C–O stretching vibration). The crystalline nature of silver NPs was confirmed by SAED. EDX analysis reveals the purity and the chemical composition of silver NPs. Nanoparticles were highly effective against Proteus mirabilis (24 mm zone of inhibition) and Bacillus substilis (24 mm zone of inhibition). The anticancer activity of the silver nanoparticles tested against colorectal adenocarcinoma cell lines increased at increasing concentrations of nanoparticles

Partioning of dietary energy of chickens fed maize or wheat-based diets with and without a commercial blend of phytogenic feed additives

The aim of the study was to investigate the effects of a standardized mixture of a commercial blend of phytogenic feed additives containing 5% carvacrol, 3% cinnamaldehyde, and 2% capsicum on utilization of dietary energy and performance in broiler chickens. Four experimental diets were offered to the birds from 7 to 21 d of age. These included 2 basal control diets based on either wheat or maize that contained 215 g CP/kg and 12.13 MJ/kg ME and another 2 diets using the basal control diets supplemented with the plant extracts combination at 100 mg/kg diet. Each diet was fed to 16 individually penned birds following randomization. Dietary plant extracts improved feed intake and weight gain (P 0.05) but improved (P < 0.05) dietary NE by reducing the heat increment (P < 0.05) per kilogram feed intake. Feeding phytogenics improved (P < 0.05) total carcass energy retention and the efficiency of dietary ME for carcass energy retention. The number of interactions between type of diet and supplementary phytogenic feed additive suggest that the chemical composition and the energy to protein ratio of the diet may influence the efficiency of phytogenics when fed to chickens. The experiment showed that although supplementary phytogenic additives did not affect dietary ME, they caused a significant improvement in the utilization of dietary energy for carcass energy retention but this did not always relate to growth performance

Langmuir wave self-focusing versus decay instability

Electron trapping in a finite amplitude Langmuir wave (LW) leads to a frequency shift, \Delta\omega_{TP} < 0, and reduced Landau damping. These may lead to modulational instability. Its growth rate and damping threshold, due to escape of trapped electrons at rate \nu, are calculated for the first time in the short wavelength regime. If the background plasma is in thermal equilibrium, it is shown that this trapped particle modulational instability (TPMI) is not possible when k \lambda_D > 0.46, while for 0.33 < k \lambda_D < 0.46, TPMI requires that the fluctuation wavevector have a component perpendicular to k, the LW wavevector, with \lambda_D the electron Debye length. Its nonlinear evolution leads to self-focusing. Comparison is made with a re-evaluated LW ion acoustic decay instability (LDI): compared to classical estimates, the new LDI threshold is lowered by primary LW \Delta\omega_{TP} since frequency matching leads to wavenumber and hence damping reduction of the daughter LW. For parameters estimates relevant to a recent stimulated Raman scatter experiment (Kline et al., submitted to PRL), the LDI and TPMI thresholds cross in the range 0.28 < k \lambda_D < 0.34, consistent with the observed LDI regime change. However, if \nu exceeds a critical value, estimated to be order 1% of the electron plasma frequency, then TPMI is not possible at any wavenumber

Awareness of Online Library Services and Frequency of Utilization of Online Resources during Covid- 19 Pandemic among Education Students

As the Covid-19 greatly affected the libraries, so too did the librarians\u27 attempts to reach the library users through online and remote services. These emergency reforms have offered an unexpected opportunity to re-evaluate and re-imagine current service models in order to improve the library\u27s user experience. This study looks into the awareness of online library services and the frequency of utilization of online resources among education students during the COVID 19 Pandemic. Descriptive in nature, the study utilized an online survey which was accomplished by 70 students of the College of Education. Findings revealed that respondents are fully aware of the online library services and they frequently utilize the library\u27s online resources regardless of their gender, program, and year level. Findings also showed that the higher the level of respondents’ awareness on online library services, the more frequent they utilize the online resources. As a whole, the results imply that libraries need to ensure the sustainability of their online resources and services by providing user education and supporting the users to cope-up with the changing information environment so that optimum use of information resources becomes possible during and after the pandemic