The Abundance and biodiversity of arthropods in biofuel crops: Insects and arachnids in corn, switchgrass and native mixed grass prairie fields

Concerns about fossil fuel prices and harmful effects have prompted research and investment in biofuel development. Biofuels have the potential to provide a stable fuel source that reduces carbon emissions. However, the ecological impacts of different crop choices should be examined. Arthropod communities in corn and switchgrass monocultures and mixed grass prairie polycultures were examined to determine the impact of the crop choice on the arthropod communities. Results show that, when compared to corn and switchgrass fields, mixed grass prairie fields had higher values for arthropod biomass, number, size, the number of orders present, the number of individuals in each order, and the overall arthropod diversity. Corn fields were dominated by Diptera (61.83%) and contained very low abundance of the other orders found in this study. Mixed grass prairie fields also showed Diptera as the most prevalent order (43.47%), followed by Hemiptera (17.89%) and Homoptera (13.65%), Hymenoptera (6.12%), Coleoptera (5.61%), with the others each less than 2.5%, Thysanoptera, Acari, Araneae, Lepidoptera, Orthoptera and Odonata. Switchgrass fields showed arthropod communities with diversity levels between that of corn and mixed grass prairies, with Diptera (39.33%), Coleoptera (17.91%) and Hemiptera (16.33%) dominating the community. Hymenoptera 5.53% and Lepidoptera, Odonata, Orthoptera, Thysanoptera, Acari and Araneae total 17%. Average arthropod abundance was 49.33 individuals and 98 milligrams in mixed grass prairie fields, 35.59 individuals and 49 milligrams in switchgrass fields, and only 23.93 individuals and 23 milligrams in corn fields. The average number of orders found was also correlated to field type, with 4.17 in corn fields, 5.53 in switchgrass fields, and 7.08 in mixed grass prairie fields. It is concluded that transitioning from planting fields with corn to growing mixed grass prairie, or switchgrass, for cellulosic ethanol and biodiesel production would increase the overall abundance and biodiversity of the arthropod community

A Jim Crow Welcome Home: African American World War Veterans In Knoxville, Tennessee

This essay will examine black veterans who returned to Knoxville, Tennessee after both world wars. Knoxville was a moderately sized Southern town that believed itself to be fairly progressive about racial issues. The life of average Knoxvillians was perennially disrupted in this period by two wars, two returns, and the racial tension that occasionally exploded into violence. This essay will attempt to show that the experience of Knoxville’s African American veterans was different after WWII from what it was in WWI because of the changing sympathies of the federal government, rather than because of changes within the African American community. In many ways, African Americans responded to both world wars with striking similarity: high expectations that the war would bring change, audible complaints at the hypocrisy of discrimination at home while fighting it abroad, and much disappointment in the aftermath. The federal government changed drastically, however, in its treatment of veterans, with the GI Bill, and of black soldiers, with the integration of the military. It was the combination of theses two important changes in federal policy that served as an impetus for social change. Knoxville serves as a case study within these larger historical trends

A new buoyancy instability in galaxy clusters due to streaming cosmic rays

Active Galactic Nuclei (AGN) are believed to provide the energy that prevents runaway cooling of gas in the cores of galaxy clusters. However, how this energy is transported and thermalized throughout the Intracluster Medium (ICM) remains unclear. In recent work we showed that streaming cosmic rays (CRs) destabilise sound waves in dilute ICM plasmas. Here we show that CR streaming in the presence of gravity also destabilises a pressure-balanced wave. We term this new instability the CR buoyancy instability (CRBI). In stark contrast to standard results without CRs, the pressure-balanced mode is highly compressible at short wavelengths due to CR streaming. Maximal growth rates are of order $(p_c / p_g) \beta^{1/2} \omega_{\rm ff}$, where $p_c/p_g$ is the ratio of CR pressure to thermal gas pressure, $\beta$ is the ratio of thermal to magnetic pressure and $\omega_{\rm ff}$ is the free-fall frequency. The CRBI operates alongside buoyancy instabilities driven by background heat fluxes, i.e. the heat-flux-driven buoyancy instability (HBI) and the magneto-thermal instability (MTI). When the thermal mean free path $l_{\rm mfp}$ is $\ll$ the gas scale height $H$, the HBI/MTI set the growth rate on large scales, while the CRBI sets the growth rate on small scales. Conversely, when $l_{\rm mfp} \sim H$ and $(p_c/p_g) \beta^{1/2} \gtrsim 1$, CRBI growth rates exceed HBI/MTI growth rates even on large scales. Our results suggest that CR-driven instabilities may be partially responsible for the sound waves/weak shocks and turbulence observed in galaxy clusters. CR-driven instabilities generated near radio bubbles may also play an important role redistributing AGN energy throughout clusters.Comment: Submitted to MNRA

Common mode noise modelling and resonant estimation in a three-phase motor drive system: 9-150 kHz frequency range

This paper presents an equivalent circuit impedance-based estimation method of resonances in a three-phase motor drive system to predict common-mode (CM) noise circulations in 9-150 kHz frequency range, which is not considered so far in electromagnetic interference (EMI) analysis. The paper verifies the presented method by analyzing emission spectrums of CM currents in the three-phase system. The impact of EMI filter, DC-link filter and AC motor models on the generated common mode noise at 9-150 kHz range is also investigated using the predicted equivalent impedance results at the CM voltage source. It is found, there is a high probability to have resonances within 9-150 kHz range due to the components of the drive system. Hence, the work presented is useful to model and predict the possible resonances in the whole drive system that unnecessarily increases the CM noise at this frequency range. The presented estimation method not only enables the ability to early recognition of CM current emissions injected from the drive system to the grid but also supports EMI filter design or modification for 9-150 kHz frequency range. Further, this approach significantly contributes to accelerating the drive products development and entering the market after complying the future standards.</p

The MASSIVE Survey XIII -- Spatially Resolved Stellar Kinematics in the Central 1 kpc of 20 Massive Elliptical Galaxies with the GMOS-North Integral-Field Spectrograph

We use observations from the GEMINI-N/GMOS integral-field spectrograph (IFS) to obtain spatially resolved stellar kinematics of the central $\sim 1$ kpc of 20 early-type galaxies (ETGs) with stellar masses greater than $10^{11.7} M_\odot$ in the MASSIVE survey. Together with observations from the wide-field Mitchell IFS at McDonald Observatory in our earlier work, we obtain unprecedentedly detailed kinematic maps of local massive ETGs, covering a scale of $\sim 0.1-30$ kpc. The high ($\sim 120$) signal-to-noise of the GMOS spectra enable us to obtain two-dimensional maps of the line-of-sight velocity, velocity dispersion $\sigma$, as well as the skewness $h_3$ and kurtosis $h_4$ of the stellar velocity distributions. All but one galaxy in the sample have $\sigma(R)$ profiles that increase towards the center, whereas the slope of $\sigma(R)$ at one effective radius ($R_e$) can be of either sign. The $h_4$ is generally positive, with 14 of the 20 galaxies having positive $h_4$ within the GMOS aperture and 18 having positive $h_4$ within $1 R_e$. The positive $h_4$ and rising $\sigma(R)$ towards small radii are indicative of a central black hole and velocity anisotropy. We demonstrate the constraining power of the data on the mass distributions in ETGs by applying Jeans anisotropic modeling (JAM) to NGC~1453, the most regular fast rotator in the sample. Despite the limitations of JAM, we obtain a clear $\chi^2$ minimum in black hole mass, stellar mass-to-light ratio, velocity anisotropy parameters, and the circular velocity of the dark matter halo.Comment: Accepted to Ap

Toward Miniaturized Low-Power Solutions for Intestinal Implants

Intestinal electrical stimulation via implants is already used to treat several disorders like constipation or incontinence. Stimulation parameters are most often empiric and not based on systematic studies. One prerequisite to evaluate effects of intestinal electrical stimulation is a direct assessment of intestinal motility. Some common methods are strain gauge transducers or manometry. With both the methods, it is not possible to record the exact 3-D movement. Therefore, we established a new method to record gastrointestinal motility with ultraminiaturized accelerometers, directly glued to the outer surface of the stomach, small intestine, and colon. With this technique, we were able to record precise local motility changes after electrical stimulation. Due to the low energy demand and the small size of the system, it is potentially useful for chronic measurements at multiple sites of the intestinal tract. We will present our first results regarding stimulation-dependent motility changes using up to eight implanted accelerometers in an acute pig model

Application of the Generalized Contrast-to-Noise Ratio to Assess Photoacoustic Image Quality

The generalized contrast-to-noise ratio (gCNR) is a relatively new image quality metric designed to assess the probability of lesion detectability in ultrasound images. Although gCNR was initially demonstrated with ultrasound images, the metric is theoretically applicable to multiple types of medical images. In this paper, the applicability of gCNR to photoacoustic images is investigated. The gCNR was computed for both simulated and experimental photoacoustic images generated by amplitude-based (i.e., delay-and-sum) and coherence-based (i.e., short-lag spatial coherence) beamformers. These gCNR measurements were compared to three more traditional image quality metrics (i.e., contrast, contrast-to-noise ratio, and signal-to-noise ratio) applied to the same datasets. An increase in qualitative target visibility generally corresponded with increased gCNR. In addition, gCNR magnitude was more directly related to the separability of photoacoustic signals from their background, which degraded with the presence of limited bandwidth artifacts and increased levels of channel noise. At high gCNR values (i.e., 0.95-1), contrast, contrast-to-noise ratio, and signal-to-noise ratio varied by up to 23.7-56.2 dB, 2.0-3.4, and 26.5-7.6x10^20, respectively, for simulated, experimental phantom, and in vivo data. Therefore, these traditional metrics can experience large variations when a target is fully detectable, and additional increases in these values would have no impact on photoacoustic target detectability. In addition, gCNR is robust to changes in traditional metrics introduced by applying a minimum threshold to image amplitudes. In tandem with other photoacoustic image quality metrics and with a defined range of 0 to 1, gCNR has promising potential to provide additional insight, particularly when designing new beamformers and when reporting quantitative performance without an opportunity to qualitatively assess corresponding images (e.g., in text-only abstracts)