Lucas' Theorem for Prime Powers

Lucas' theorem on binomial coefficients states that (AB)≡(arbr)⋯(a1b1)(a0b0)(mod p) where p is a prime and A = arpr + ⋯ + a0p + a0, B = brpr + ⋯ + b1p + b0 + are the p-adic expansions of A and B. If s ⩾ 2, it is shown that a similar formula holds modulo ps where the product involves a slightly modified binomial coefficient evaluated on blocks of s digits.

The Dover Mound

Fifty-five burials with their accompanying artifacts were uncovered during the excavation of the Dover Mound, located in Mason County, Kentucky, yielding new data on the cultural group known as the Adena which is reported in detail by the authors.https://uknowledge.uky.edu/upk_archaeological_anthropology/1000/thumbnail.jp

The Oxidative Decarboxylation Of Polyaminocarboxylic Acids - I. A Study Of The Reaction Of Ethylenedinitrilotetraacetic Acid (EDTA) With Cerium (IV) In Acid Solution

The reaction between Ce(IV) and EDTA was followed titrimetrically and spectrophotometrically and was found to occur in stages. Four equivalents of Ce(IV) are reduced per mole of EDTA almost instantaneously at room temperature. With increasing temperature and reaction time an ultimate of about 14 equivalents of Ce (IV) is consumed per mole of EDTA. Carbon dioxide, formaldehyde, and other yet unidentified compounds are the products of oxidation of EDTA. The kinetics of the reaction in aqueous sulfuric acid was studied over the temperature range 11.7°-40°C by a spectrophotometric technique. The effects of the acidity of the medium and of added salts are reported. © 1969 Springer-Verlag

The effect of local wind on seismic noise near 1 Hz at the MELT site and in Iceland

The mantle electromagnetic and tomography (MELT) experiment on the east Pacific rise near 17°S was the first large teleseismic experiment on a midocean ridge. During the six-month deployment, no compressional arrivals were well recorded above 0.5 Hz. In comparison, the ICEMELT experiment in Iceland recorded compressional arrivals at 1-2 Hz from about 2 earthquakes per month. We compare noise spectra from the two experiments and show that this difference in detection is at least in part a result of noise. Near 1 Hz, seismic noise in the oceans is produced locally by wind-generated waves. At both experiment sites, 1-Hz noise levels are well correlated with local sea-surface-wind speeds derived from satellite observations. For a given wind speed, 1-Hz noise levels are about 10-20 dB lower in Iceland. At the MELT site, cross-correlations of wind speed with the logarithm of noise in a narrow-frequency band yield correlation coefficients exceeding 0.7 at frequencies between 0.4 Hz and 2 Hz. Noise levels at 1 Hz increase with wind by 1.3-1.4 dB per m/sec for wind speeds less than 10 m/sec. For the ICEMELT experiment, high correlation coefficients extend to markedly higher frequencies for coastal stations, and there is a 10-dB drop in 1-Hz noise levels 100-km inland. Noise levels increase by about 0.8 dB per m/sec. The strong correlation between wind speed and l-Hz seismic noise provides justification for using satellite wind speed data to search for locations on the global spreading system where there is a better probability of recording high-frequency arrivals. The calmest sites are found on the northern east Pacific rise, near the equator in all oceans, and near 34 ° N and 22 ° S on the mid- Atlantic ridge.This study was supported by the National Science Foundation under grant OCE-9414299.Peer Reviewe

Occurrence, Resource Use, and Demography of the Common Raven in North America: a Research Synthesis

We reviewed the scientific literature to inventory existing studies of common raven (Corvus corax; raven) ecology in western North America. We conducted an intial literature review between June 2015 and March 2018. Prior to completing our review, we revisited the published literature for any additional relevant studies in July 2021. Our goal was to identify knowledge gaps and to synthesize the current understanding of environmental features that may support raven populations that pose general threats to biodiversity and sensitive species in particular. We focused our review on studies with direct conservation applications related to 3 processes of raven ecology: occurrence, resource use, and demography. We identified covariates that researchers associated with these processes of raven ecology, and we also quantified the geographic distribution of studies. Our review identified 54 studies, with an increasing number of studies published per decade and a geographic bias characterized by more studies conducted in the Mojave and Columbia Plateau ecoregions than elsewhere. Most studies (44) reported on a single ecological process, but 10 studies reported on multiple ecological processes. Results related to raven occurrence appeared 31 times; demographic results appeared 21 times; and resource use was reported 17 times. We also identified 13 explanatory covariates regularly invoked to explain variation in raven ecological processes. Greater attention was given to covariates including vegetation land cover, human settlement, recreation, and linear rights-of-ways than were used to explain variation in ecological processes. Most demographic studies investigated raven reproduction exclusively, but a small number of studies considered raven survival exclusively or in combination with reproduction. Along with a detailed summary of individual studies provided as an appendix, we intend for our findings to serve as a reference and to help identify future research priorities

Percepciones de directores y ejecutivos del Instituto Colombiano Agropecuario acerca del rol del director regional de desarrollo rural.

Se determinó si existía un conflicto entre directores y ejecutivos en la forma de percibir las funciones del Director Regional de Desarrollo Rural del Instituto. Se elaboró un cuestionario dividido en 2 secciones, la primera buscaba obtener respuesta de los funcionarios con relación a edad, último nivel académico obtenido, experiencia de trabajo con el Instituto y experiencia en Desarrollo Rural y la segunda hace referencia a las funciones que puede desempeñar el Director. Tanto directores como ejecutivos están de acuerdo con el rol que puede desempeñar en el Instituto el Director Regional de Desarrollo Rural. Las diferencias entre los grupos representados y sus respuestas se refieren más que todo al nivel en el cual están de acuerdo y no a los niveles en que no se encuentran de acuerdo. Ambos grupos percibieron que el rol de Director incluye 38 funciones del cuestionario y que tres de los enunciados no describen funciones. Existen diferencias marcadas entre ejecutivos y Directores para las características de: edad, entrenamiento y experiencia de trabajo con el Institut

Synthesis of Nest Predation Impacts of Common Ravens on Sensitive Avian Species

Decades of mounting scientific evidence have revealed that common raven (Corvus corax; raven) population numbers have been increasing across nearly all regions of their geographic range in North America. Concomitantly, numerous native wildlife species have experienced elevated predation rates from ravens as populations have increased and expanded their range. Managers are concerned that increased raven predation of many threatened and endangered avian species in the U.S. and Canada during nesting periods may be hampering species recovery. We explored the literature to aggregate existing knowledge and evaluate the impacts of raven predation on nests and young of sensitive avian species. We used this information to develop a simple relative index for each species, the “Raven Impact Index” (RII). The RII incorporated the species demographic rates, abundance of ravens in relation to each sensitive species’ breeding range, and the degree of overlap between raven and sensitive prey distributions. We also developed a second relative descriptor describing our confidence in each RII, termed a “Impact Credibility Index (ICI).” The species ICI was based on the number of published studies and the type of evidence presented (e.g., circumstantial vs. direct). We found evidence of nest predation on 8 sensitive avian species and suspected nest predation on 1 additional species. All species shared aspects of nesting biology that suggested they would likely be susceptible to raven nest predation. The RII varied among prey species, with greater sage-grouse (Centrocercus urophasianus) having the highest relative impact values, followed by snowy plover (Charadrius nivosus nivosus), marbled murrelet (Brachyramphus marmoratus), and Gunnison sage-grouse (Centrocercus minimus). Our species RII is intended to inform management decisions regarding actions that mitigate the negative effects of raven predation of sensitive avian species. Although elevated nest predation may be of high conservation concern, it is important to recognize that all of the sensitive native prey species we established an RII for also face multiple conservation threats

Movements of Spawning and Non-Spawning Shovelnose Sturgeon in the Missouri River Above Fort Peck Reservoir

During the last 40 yrs there has been a lack of pallid sturgeon (Scaphirhynchus albus) recruitment in the upper Missouri River (UMR). However, shovelnose sturgeon (Scaphirhynchus platorynchus) continue to exhibit recruitment in the UMR. Understanding the recruitment dichotomy between species is receiving much attention throughout their range. The objectives of this study were to identify the effects of varying discharge on spawning locations and spawning movements for pallid and shovelnose sturgeon. Two female pallid sturgeon, 32 gravid female shovelnose sturgeon, and 32 non-reproductively active female shovelnose sturgeon were radio tagged at three locations and tracked from 1 May to 5 July 2009. Unfortunately, no data are available for spawning pallid sturgeon movements because fish were not reproductively active. Upstream movement by gravid shovelnose sturgeon varied from 20 percent of the fish tagged at Judith Landing to 56 percent of the fish tagged at Coal Banks Recreation Area (CBRA). Mean maximum upstream movement of gravid shovelnose sturgeon varied from 35.7 km at CBRA to 87.9 km at Fred Robinson Bridge (FRB), mean maximum downstream movement varied from 24.9 km at FRB to 80.3 km at CBRA. Reproductively inactive shovelnose sturgeon exhibited lower mean maximum movements than reproductively active fish (mean maximum distance 5.7 km). Shovelnose sturgeon in the UMR exhibit both upstream and downstream movements prior to spawning and are using several spawning areas. Thus, maintaining spawning habitat throughout a regulated river is important with regard to shovelnose sturgeon conservation

Additively Manufactured RCS for Small Satellites and Landers

After a fifty year absence, NASA’s return to the lunar surface under the Artemis Program – for long term human exploration and utilization – is driving commercial and academic opportunities for small satellite and small lander platforms (e.g., Commercial Lunar Payload Services program – CLPS). Bipropellant thrusters are a reliable, low risk, and flight proven method for the propulsion and attitude control that is required for complex maneuvers such entry, descent, and landing (EDL) or in-space proximity operations. However, due to the increasingly competitive commercial spaceflight market in the last decade, satellite subsystems must also be affordable to buy their way into the final mission design and engineering solution. Therefore starting in 2019, and based off prior satellite integration work, Aerojet Rocketdyne (AR) undertook an advanced propulsion development effort to combine modern metal additive manufacturing (AM) techniques with thrust scalable hypergolic MON-25 propulsion technology to create a high performance and fully integrated (i.e., multiple thrusters integrated into a single package) reaction control system (RCS) at a fraction of the production cost when compared to the heritage designs that are assembled from individual thrusters. The point-of-departure for the RCS design comes from a new line of additively manufactured thrusters that stably burn volatile MON-25 oxidizer with monomethylhydrazine (MMH) fuel at thrust levels of 5 lbf and 100 lbf. Cost at the subsystem level is lowered by the AM integration of parts and functions which reduces the build of materials, touch labor, and assembly time. In addition, AM allows the design to be adaptable to changing requirements such as the number of thrusters, orientation, and thrust level. Cost at the satellite level is reduced by leveraging MON-25’s lower freezing point of -55 °C (compared to traditional dinitrogen tetroxide oxidizer) to minimize mass, thermal, and power requirements while operating in deep-space environments. In addition, thruster operation at the equal volume mixture ratio for MMH/MON-25 allows for a modular approach to tank design and a predictable center of gravity during maneuvering. This paper provides an overview of the ISE-5 and the ISE-100 MON-25 thruster technology that powers the integrated designs as well as the development progress of the AM RCS concept itself. This includes reduction to practice activities such as proof-of-concept AM material test demonstrators and water flow test units