Scholarworks
ScholarWorks is an open access repository for the capture of the intellectual work of Montana State University (MSU) in support of its teaching, research and service missions. MSU ScholarWorks is a central point of discovery for accessing, collecting, sharing, preserving, and distributing knowledge to the Montana State University community and the world.
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Cool semi-arid cropping treatments alter Avena fatua's performance and competitive intensity
(Wiley, 2024-03) Larson, Christian D.; Wong, Mei Long; Carr, Patrick M.; Seipel, Timothy
Introduction. Multiple herbicide-resistant Avena fatua L. is common in the Northern Great Plains, USA. This prevalence and the ecological impacts of tillage in this semi-arid agricultural region have created a need for integrated weed management, with a specific knowledge gap in using annual forage crops and targeted grazing for A. fatua suppression. Materials and Methods. A 2-year study in central Montana, USA, assessed A. fatua performance (aboveground biomass, stem density and seed production) in response to seven cropping treatments: (1–4) tall and short spring wheat cultivars crossed with high and low seeding rates, (5–6) annual forage mixture terminated using sheep grazing and simulated haying and (7) tilled fallow. Avena fatua's competitive intensity in wheat and the annual forage mixture was determined using a relative competition intensity index. Results. Avena fatua performance was lowest in tilled fallow, although stem density and seed production did not differ from the grazed annual forage treatment. Response variables were lower in the forage treatments compared with the wheat treatments, and there were no differences among the four fully crossed wheat treatments. Separate analysis of the wheat treatments indicated lower A. fatua biomass and stem density when wheat was sown at a higher rate with no impact of wheat height. Avena fatua competition impacted wheat and forage crops but was more intense for wheat. Conclusion. Tillage was the most effective treatment at reducing A. fatua performance, but annual forage mixtures can be used to resist A. fatua invasion (reduced A. fatua competitive intensity) and limit its performance after invasion. We conclude that crop sequences that combine higher cash crop (wheat) seeding rates and competitive annual forage mixtures may be utilized to manage A. fatua invaded systems, thereby reducing heavy reliance on tillage in the US Northern Great Plains and similar semi-arid regions.
Dynamical tides during the inspiral of rapidly spinning neutron stars: Solutions beyond mode resonance
(American Physical Society, 2024-07) Yu, Hang; Arras, Phil; Weinberg, Nevin N.
We investigate the dynamical tide in a gravitational wave (GW)-driven coalescing binary involving at least one neutron star (NS). The deformed NS is assumed to spin rapidly, with its spin axis antialigned with the orbit. Such an NS may exist if the binary forms dynamically in a dense environment, and it can lead to a particularly strong tide because the NS f-mode can be resonantly excited during the inspiral. We present a new analytical solution for the f-mode resonance by decomposing the tide into a resummed equilibrium component varying at the tidal forcing frequency and a dynamical component varying at the f-mode eigenfrequency that is excited only around mode resonance. This solution simplifies numerical implementations by avoiding the subtraction of two diverging terms as was done in previous analyses. It also extends the solution’s validity to frequencies beyond mode resonance. When the dynamical tide back reacts on the orbit, we demonstrate that the commonly adopted effective Love number is insufficient because it does not capture the tidal torque on the orbit that dominates the back reaction during mode resonance. An additional dressing factor originating from the imaginary part of the Love number is therefore introduced to model the torque. The dissipative interaction between the NS and the orbital mass multipoles is computed including the dynamical tide and shown to be subdominant compared to the conservative energy transfer from the orbit to the NS modes. Our study shows that orbital phase shifts caused by the 𝑙=3 and 𝑙=2 f-modes can reach 0.5 and 10 radians at their respective resonances if the NS has a spin rate of 850 Hz and direction antialigned with the orbit. Because of the large impact of the 𝑙=2 dynamical tide, a linearized analytical description becomes insufficient, calling for future developments to incorporate higher-order corrections. After mode excitation, the orbit cannot remain quasicircular, and the eccentricity excited by the 𝑙=2 dynamical tide can approach nearly 𝑒≃0.1, leading to nonmonotonic frequency evolution which breaks the stationary phase approximation commonly adopted by frequency domain phenomenological waveform constructions. Lastly, we demonstrate that the GW radiation from the resonantly excited f-mode alone can be detected with a signal-to-noise ratio exceeding unity at a distance of 50 Mpc with the next-generation GW detectors.
Adenosine modifications impede SARS-CoV-2 RNA-dependent RNA transcription
(Cold Spring Harbor Laboratory, 2024-06) Snyder, Laura R.; Kilde, Ingrid; Nemudryi, Artem; Wiedenheft, Blake; Koutmos, Markos; Koutmou, Kristin S.
SARS-CoV-2, the causative virus of the COVID-19 pandemic, follows SARS and MERS as recent zoonotic coronaviruses causing severe respiratory illness and death in humans. The recurrent impact of zoonotic coronaviruses demands a better understanding of their fundamental molecular biochemistry. Nucleoside modifications, which modulate many steps of the RNA life cycle, have been found in SARS-CoV-2 RNA, although whether they confer a pro- or antiviral effect is unknown. Regardless, the viral RNA-dependent RNA polymerase will encounter these modifications as it transcribes through the viral genomic RNA. We investigated the functional consequences of nucleoside modification on the pre-steady state kinetics of SARS-CoV-2 RNA-dependent RNA transcription using an in vitro reconstituted transcription system with modified RNA templates. Our findings show that N6-methyladenosine and 2′-O-methyladenosine modifications slow the rate of viral transcription at magnitudes specific to each modification, which has the potential to impact SARS-CoV-2 genome maintenance.
Divergent Electrically Conductive Pathways in Yttrium-Based 2- and 3-Dimensional Metal–Organic Frameworks
(American Chemical Society, 2024-07) Welty, Connor; Gormley, Eoghan L.; Oppenheim, Julius J.; Dincă, Mircea; Hendon, Christopher H.; Stadie, Nicholas P.
Despite most porous framework solids exhibiting insulating character, some are known to conduct electrical charge. The peak performing conductive metal–organic frameworks are composed of redox-active hexasubstituted triphenylene linkers, but the impact of redox activity on material conductivity remains enigmatic because of limited availability of direct structure–function relationships. Here, we report a hexagonal yttrium-based conductive porous scaffold, comprising hexahydroxytriphenylene connected by Y-chains (YHOTP). In comparison to its known porous cubic counterpart (Y6HOTP2), this material features a 1000-fold increase in peak conductivity in polycrystalline samples (∼10–1 S cm–1). Furthermore, through a comparison of their electronic structures, we rationalize the origin of this difference and highlight the role of charge carrier concentration in dictating bulk electrical conductivity. Together, this work provides a design principle for the development of next-generation conductive porous frameworks.
Brief Psychoeducational Group for Stroke Survivors and Family Caregivers
(Ohio Counseling Association, 2024-04) Gonzalez-Voller, Jessica; Wood, Andrew W.; Lamb, Bryan C.; Sladkowski, Christina
As group leaders aim to benefit the well-being of individuals, it is important to examine each individual from a systemic and holistic point of view. This becomes integral when individuals experience acute distress due to medical concerns, such as stroke. The integrated care team surrounding a stroke survivor includes physical health professionals, mental health professionals, and family caregivers. Family caregivers often provide unpaid caregiving services to a loved one who experienced medical issues. Having a stroke can be particularly distressing and has unique implications for family caregiving (Rigby et al., 2009). Stroke survivors and their family caregivers are at risk for experiencing symptoms of depression and anxiety (Balhara et al., 2012), and if left untreated, symptoms could worsen. In working to support the emotional needs of stroke survivors and their family caregivers, the authors designed this brief group curriculum to provide psychoeducation on common psychological symptoms of distress this population may experience and tools for them to cope with those stressors.