Koinonia

Best Practices FeaturesStudents of Concern Committee: Coordinating Care, Connie Horton and Mark Davis Want to Change Student Culture on Your Campus? Do the CORE!, Eric Lowdermilk Spotlight FeaturesYou Only Get 1 Up, Justin Heth and Caleb Farmer The Season, Sharon Virkler Book ReviewsThe Future of Christian Learning: An Evangelical and Catholic Dialogue (by Mark Noll and James Turner), reviewed by Philip D. Byers Restoring Rebecca: A Story of Traumatic Stress, Caregiving and the Unmasking of a Superhero (by Christopher Marchand), reviewed by David M. Johnstone A Review of Culture Making: Recovering our Creative Calling (by Andy Crouch), reviewed by Jeff Rioux Revisiting How Minority Students Experience College: Implications for Planning and Policy (by LKemuel Watson, Melvin Terrell, Doris Wright, Fred Bonner II, Michael Cuyjet, James Gold, Donna Rudy and Dawn Person), reviewed by Joshua Canada Excerpts from Breathe: Finding Freedom to Thrive in Relationships after Childhood Sexual Abuse, Nicole Braddock Bromley ReflectionsMy Journey into Student Affairs, Kim Stave FeaturesThe President\u27s Corner Editor\u27s Deskhttps://pillars.taylor.edu/acsd_koinonia/1079/thumbnail.jp

Space Based Gravitational Wave Astronomy Beyond LISA

The Laser Interferometer Space Antenna (LISA) will open three decades of gravitational wave(GW) spectrum between 0.1 and 100 mHz, the mHz band [1]. This band is expected to be the richest part of the GW spectrum, in types of sources, numbers of sources, signal-to-noise ratios and discovery potential. When LISA opens the low-frequency window of the gravitational wave spectrum,around 2034, the surge of gravitational-wave astronomy will strongly compel a subsequent mission to further explore the frequency bands of the GW spectrum that can only be accessed from space. The 2020's is the time to start developing technology and studying mission concepts for a large-scale mission to be launched in the 2040's. The mission concept would then be proposed to Astro2030. Only space-based missions can access the GW spectrum between 108 and 1 Hz because of the Earth's seismic noise. This white paper surveys the science in this band and mission concepts that could accomplish that science. The proposed small scale activity is a technology development program that would support a range of concepts and a mission concept study to choose a specific mission concept for Astro2030. In this white paper, we will refer to a generic GW mission beyond LISA as bLISA

Building a Field: The Future of Astronomy with Gravitational Waves

Harnessing the sheer discovery potential of GW Astronomy will require bold, deliberate,and sustained efforts to train and develop the requisite workforce. The next decaderequires a strategic plan to build - from the ground up - a robust, open, andwell-connected GW Astronomy community with deep participation from traditionalastronomers, physicists, data scientists, and instrumentalists. This basic infrastructure issorely needed as an enabling foundation for research. We outline a set ofrecommendations for funding agencies, universities, and professional societies to helpbuild a thriving, diverse, and inclusive new field

Statistics for Fission-Track Thermochronology

This chapter introduces statistical tools to extract geologically meaningful information from fission-track (FT) data using both the external detector and LA-ICP-MS methods. The spontaneous fission of 238U is a Poisson process resulting in large single-grain age uncertainties. To overcome this imprecision, it is nearly always necessary to analyse multiple grains per sample. The degree to which the analytical uncertainties can explain the observed scatter of the single-grain data can be visually assessed on a radial plot and objectively quantified by a chi-square test. For sufficiently low values of the chi-square statistic (or sufficiently high p values), the pooled age of all the grains gives a suitable description of the underlying ‘true’ age population. Samples may fail the chi-square test for several reasons. A first possibility is that the true age population does not consist of a single discrete age component, but is characterised by a continuous range of ages. In this case, a ‘random effects’ model can constrain the true age distribution using two parameters: the ‘central age’ and the ‘(over)dispersion’. A second reason why FT data sets might fail the chi-square test is if they are underlain by multimodal age distributions. Such distributions may consist of discrete age components, continuous age distributions, or a combination of the two. Formalised statistical tests such as chi-square can be useful in preventing overfitting of relatively small data sets. However, they should be used with caution when applied to large data sets (including length measurements) which generate sufficient statistical ‘power’ to reject any simple yet geologically plausible hypothesis

Fast subduction, slow exhumation: dating continental subduction beneath the Oman ophiolite

Continent subduction beneath continental upper plates has occurred at a broad range of rates that correlate with the size of the subducted fragment: small slivers subduct and exhume fast and cold while larger fragments undergo much slower and hotter orogenesis (Kylander-Clark et al., 2012). The few extant examples of continental fragments subducted beneath oceanic crust record cold geothermal gradients (<10 °C/km), but rates associated with this process are uncertain. To better constrain these rates, we dated garnet, zircon, and rutile from the (U)HP As Sifah unit in the Saih Hatat of Oman. Existing geochronology from As Sifah suggests that either i) continental subduction occurred at ~110 Ma (Gray et al., 2004), predating ophiolite formation by ≥15 My, or ii) occurred at ~79 Ma (Warren et al., 2005), 15 My after initial emplacement of the ophiolite nappe. New dates from multiple lithologies in the As Sifah unit show that 1) previously published Sm-Nd dates are likely inaccurate and 2) multi-grain U-Pb zircon TIMS dates may be averages of long-term metamorphism. Our data suggest that garnet growth started by ~85 Ma – ~11 Myr after formation of the ophiolite crust – and lasted until at least ~74 Ma. Combined with other thermobarometric and structural constraints, these data indicate a subduction rate of 7±2 mm/yr and an exhumation rate of 3±2 mm/yr for the Arabian continental margin. The duration of HP metamorphism is similar to other continental fragments subducted beneath ophiolites (e.g., New Caledonia, Corsica). Our data show that As Sifah behaved as a small continental sliver during subduction yet like a larger continental body during exhumation – consistent with subduction of extended continental crust followed by thickening

Frequency tunable continuous THz wave generation in a periodically poled fiber

An all-fiber approach to terahertz generation using a periodically poled optical fiber is proposed and experimentally demonstrated. In the proposed approach, a continuous-wave THz wave is generated at a periodically poled fiber by beating two optical wavelengths from two laser sources with the wavelength spacing corresponding to the frequency of the THz wave. The key component in the system is the periodically poled fiber, which is made by a twin-hole fiber with the fiber core residing between two holes. The twin-hole fiber is then thermally poled at a temperature of similar to 260 degrees C with a voltage of 3.3 kV applied to the silver electrodes inside the two holes to introduce second-order nonlinearity. The quasi phase matching (QPM) condition is achieved by periodically erasing the thermal poling induced second-order nonlinearity with an ultraviolet laser, which enhances the energy conversion efficiency. The proposed approach is validated by an experiment. The emission of a THz wave centered at 3.8 THz with an output power of 0.5 mu W is observed. The frequency tunability between 2.2 and 3.8 THz is also experimentally demonstrated

A Wireless Multi-Sensor Dielectric Impedance Spectroscopy Platform

This paper describes the development of a low-cost, miniaturized, multiplexed, and connected platform for dielectric impedance spectroscopy (DIS), designed for in situ measurements and adapted to wireless network architectures. The platform has been tested and used as a DIS sensor node on ZigBee mesh and was able to interface up to three DIS sensors at the same time and relay the information through the network for data analysis and storage. The system is built from low-cost commercial microelectronics components, performs dielectric spectroscopy ranging from 5 kHz to 100 kHz, and benefits from an on-the-fly calibration system that makes sensor calibration easy. The paper describes the microelectronics design, the Nyquist impedance response, the measurement sensitivity and accuracy, and the testing of the platform for in situ dielectric impedance spectroscopy applications pertaining to fertilizer sensing, water quality sensing, and touch sensing

Controlling the Orientation and Synaptic Differentiation of Myotubes with Micropatterned Substrates

Micropatterned poly(dimethylsiloxane) substrates fabricated by soft lithography led to large-scale orientation of myoblasts in culture, thereby controlling the orientation of the myotubes they formed. Fusion occurred on many chemically identical surfaces in which varying structures were arranged in square or hexagonal lattices, but only a subset of patterned surfaces yielded aligned myotubes. Remarkably, on some substrates, large populations of myotubes oriented at a reproducible acute angle to the lattice of patterned features. A simple geometrical model predicts the angle and extent of orientation based on maximizing the contact area between the myoblasts and patterned topographic surfaces. Micropatterned substrates also provided short-range cues that influenced higher-order functions such as the localization of focal adhesions and accumulation of postsynaptic acetylcholine receptors. Our results represent what we believe is a new approach for musculoskeletal tissue engineering, and our model sheds light on mechanisms of myotube alignment in vivo