Emergent behaviour in a chlorophenol-mineralising three-tiered microbial `food web'

Anaerobic digestion enables the water industry to treat wastewater as a resource for generating energy and recovering valuable by-products. The complexity of the anaerobic digestion process has motivated the development of complex models. However, this complexity makes it intractable to pin-point stability and emergent behaviour. Here, the widely used Anaerobic Digestion Model No. 1 (ADM1) has been reduced to its very backbone, a syntrophic two-tiered microbial food chain and a slightly more complex three-tiered microbial food web, with their stability analysed as function of the inflowing substrate concentration and dilution rate. Parameterised for phenol and chlorophenol degradation, steady-states were always stable and non-oscillatory. Low input concentrations of chlorophenol were sufficient to maintain chlorophenol- and phenol-degrading populations but resulted in poor conversion and a hydrogen flux that was too low to sustain hydrogenotrophic methanogens. The addition of hydrogen and phenol boosted the populations of all three organisms, resulting in the counterintuitive phenomena that (i) the phenol degraders were stimulated by adding hydrogen, even though hydrogen inhibits phenol degradation, and (ii) the dechlorinators indirectly benefitted from measures that stimulated their hydrogenotrophic competitors; both phenomena hint at emergent behaviour.Comment: 19 pages, 8 figure

Optimal Grazing Termination Date for Dual-Purpose Winter Wheat Production

Dual-purpose winter wheat (fall-winter forage plus grain) production is an important economic enterprise in the southern Great Plains. Grazing termination to enable grain production is a critical decision. The objective is to determine the optimal grazing termination date for dual-purpose wheat. The value of knowing the occurrence of first hollow stem (FHS), a wheat growth threshold for grazing termination, is also determined. Results indicate that for most price situations grazing should be terminated at or before FHS. Marginal wheat returns from extended grazing were negative and the value of FHS information ranges from $1.50 to$10 per acre.dual-purpose, first hollow stem, plateau function, stocker cattle, value of information, wheat, Agribusiness, Agricultural Finance, Crop Production/Industries, Farm Management, Land Economics/Use, Livestock Production/Industries, Production Economics, Q12, Q16,

Racialized Sexual Discrimination (RSD) in the Age of Online Sexual Networking: Are Young Black Gay/Bisexual Men (YBGBM) at Elevated Risk for Adverse Psychological Health?

Young Black gay/bisexual men (YBGBM) are a highly marginalized population across multiple health outcomes. Most research on YBGBM health has focused on HIV/sexual health, but there is a demonstrable need for research examining racism and psychosocial functioning among this population. Racialized Sexual Discrimination (RSD), also known as sexual racism, is an important but under‐investigated phenomenon that may have implications for the psychological health and well‐being of YBGBM. This paper provides an overview of empirical research on RSD as experienced by gay/bisexual men of color in online partner‐seeking venues. First, the researchers discuss how racialized experiences are a documented online phenomenon, with a variety of manifestations, and identify the potential effects that this phenomenon may have on the psychosocial health of YBGBM, and gay/bisexual men of color as a whole. Second, the researchers synthesize the RSD literature with a broader literature examining psychological well‐being across race and sexual orientation. Third, the researchers present a theoretically grounded conceptual model detailing the pathways between RSD and psychological well‐being using a stress and coping framework. The paper concludes with recommendations for future research on this topic, including scale development and hypothesis testing.HighlightsRacialized Sexual Discrimination (RSD) is a multidimensional yet understudied construct.RSD, also known as sexual racism, is widely perpetuated in online hook‐up websites for gay men.RSD may negatively impact the psychological health of gay/bisexual men of color.There is an imperative to develop robust measurement tools to capture the full extent of RSD.A conceptual and analytic model to guide scientific inquiry into RSD is proposed.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155883/1/ajcp12401.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155883/2/ajcp12401_am.pd

The Effects of Acute Resistance Exercise on Vascular and Cognitive Function

Please refer to the pdf version of the abstract located adjacent to the title

An Assessment of Microcomputer Competencies Needed by Vocational Agriculture Instructors in Nebraska and Iowa

In order to provide effective preservice and inservice instruction to vocational agriculture teachers, certain baseline data are necessary. It was the intent of this study to: a) identify specific microcomputer competencies needed by vocational agriculture instructors and to make comparisons by state, size of vocational agriculture department, and years of teaching experience; b) identify barriers that may impede the use of microcomputers; and c) assess the current status of microcomputer usage in Nebraska and Iowa vocational agriculture programs

Effects of sex chromosome dosage on corpus callosum morphology in supernumerary sex chromosome aneuploidies.

BackgroundSupernumerary sex chromosome aneuploidies (sSCA) are characterized by the presence of one or more additional sex chromosomes in an individual's karyotype; they affect around 1 in 400 individuals. Although there is high variability, each sSCA subtype has a characteristic set of cognitive and physical phenotypes. Here, we investigated the differences in the morphometry of the human corpus callosum (CC) between sex-matched controls 46,XY (N =99), 46,XX (N =93), and six unique sSCA karyotypes: 47,XYY (N =29), 47,XXY (N =58), 48,XXYY (N =20), 47,XXX (N =30), 48,XXXY (N =5), and 49,XXXXY (N =6).MethodsWe investigated CC morphometry using local and global area, local curvature of the CC boundary, and between-landmark distance analysis (BLDA). We hypothesized that CC morphometry would vary differentially along a proposed spectrum of Y:X chromosome ratio with supernumerary Y karyotypes having the largest CC areas and supernumerary X karyotypes having significantly smaller CC areas. To investigate this, we defined an sSCA spectrum based on a descending Y:X karyotype ratio: 47,XYY, 46,XY, 48,XXYY, 47,XXY, 48,XXXY, 49,XXXXY, 46,XX, 47,XXX. We similarly explored the effects of both X and Y chromosome numbers within sex. Results of shape-based metrics were analyzed using permutation tests consisting of 5,000 iterations.ResultsSeveral subregional areas, local curvature, and BLDs differed between groups. Moderate associations were found between area and curvature in relation to the spectrum and X and Y chromosome counts. BLD was strongly associated with X chromosome count in both male and female groups.ConclusionsOur results suggest that X- and Y-linked genes have differential effects on CC morphometry. To our knowledge, this is the first study to compare CC morphometry across these extremely rare groups

Discovery of a strong magnetic field in the rapidly rotating B2Vn star HR 7355

We report the detection of a strong, organized magnetic field in the helium-variable early B-type star HR 7355 using spectropolarimetric data obtained with ESPaDOnS on the 3.6-m Canada-France-Hawaii Telescope within the context of the Magnetism in Massive Stars (MiMeS) Large Program. HR 7355 is both the most rapidly rotating known main-sequence magnetic star and the most rapidly rotating helium-strong star, with $v \sin i$ = 300 $\pm$ 15 km s$^{-1}$ and a rotational period of 0.5214404 $\pm$ 0.0000006 days. We have modeled our eight longitudinal magnetic field measurements assuming an oblique dipole magnetic field. Constraining the inclination of the rotation axis to be between $38^{\circ}$ and $86^{\circ}$, we find the magnetic obliquity angle to be between $30^{\circ}$ and $85^{\circ}$, and the polar strength of the magnetic field at the stellar surface to be between 13-17 kG. The photometric light curve constructed from HIPPARCOS archival data and new CTIO measurements shows two minima separated by 0.5 in rotational phase and occurring 0.25 cycles before/after the magnetic extrema. This photometric behavior coupled with previously-reported variable emission of the H$\alpha$ line (which we confirm) strongly supports the proposal that HR 7355 harbors a structured magnetosphere similar to that in the prototypical helium-strong star, $\sigma$ Ori E.Comment: 6 pages, 3 figures. Accepted for publication in MNRAS Letter

DERIVATION AND OPTIMIZATION OF A STOCHASTIC LIVESTOCK WEIGHT GAIN RESPONSE TO STOCKING DENSITY MODEL

Dual-purpose winter wheat production is an important economic enterprise in the southern Great Plains of the United States. Because of the complex interactions involved in producing wheat grain and beef gain from a single crop, stocking density is an important decision. The objective of the research is to determine the stocking density that maximizes expected net returns from dual-purpose winter wheat production. Statistical tests rejected a conventional linear-response plateau function in favor of a linear-response stochastic plateau function. The optimal stocking density of 1.48 steers per hectare (0.60 steers per acre) is 19% greater with a stochastic plateau than with a nonstochastic one.Livestock Production/Industries,