992 research outputs found
Non-Mendelian Segregation Of The Maize Embryo-Specific Mutation UND-9
The maize mutant UND-9 is being studied in our lab as part of a larger study into the genes responsible for embryo development in maize. It is known as an embryo-specific mutant, which causes the embryo of the maize kernel to fail to develop fully while not hindering the development of the endosperm. During this study, it was discovered that the inheritance of this mutation appeared to behave in a manner contrary to the normal laws of Mendelian inheritance. This paper represents a deeper study into the mechanisms of this behavior, analyzing the data collected so far and in particular whether transmission through either the male or female gametophyte has any effect on the presence of the mutation in further generations. We conclude that while some trends in the non-Mendelian behavior are inheritable, we find little evidence of gametophytes playing an abnormal role, and set the stage for future studies with a new hypothetical model
NEW AND UPDATED RECORDS FOR AMPHIBIANS AND REPTILES IN MINNESOTA, USA
Following the publication of the revised edition of “Amphibians and Reptiles in Minnesota” by Moriarty and Hall (2014), we accessioned several new or updated records at the Bell Museum of Natural History (JFBM). Records include digital photographs (accession number preceded by “P”) and audio recordings (accession number preceded by “AUD”). In addition, a subset of these observations were accessioned in www.HerpMapper.org. HerpMapper accession numbers are preceded by “HM” and can be viewed online. Benjamin Lowe verified species determinations. Latitude and longitude coordinates are based on datum WGS 84
Analysis of Factors Affecting Farmers’ Willingness to Adopt Switchgrass Production
In the United States, biomass is the largest source of renewable energy accounting for over 3 percent of the energy consumed domestically and is currently the only source for liquid, renewable, transportation fuels. Continued development of biomass as a renewable energy source is being driven in large part by the Energy Independence and Security Act of 2007, which mandates that by 2022 at least 36 billion gallons of fuel ethanol be produced, with at least 16 billion gallons being derived from cellulose, hemi-cellulose, or lignin. However, the market for cellulosic biofuels is still under development. As such, little is known about producer response to feedstock prices paid for dedicated energy crops. While there have been some studies done on factors that determine farmers’ willingness to produce switchgrass, these have been very regional in nature. This study will provide information regarding potential switchgrass adoption by agricultural producers in twelve southeastern states. The objectives of this research are 1) to determine the likelihood of farmers growing switchgrass as a biomass feedstock and the acres they would be willing to devote to switchgrass production and 2) to evaluate some of the factors that are likely to influence these decisions, including the price of switchgrass.Switchgrass, Farmer Adoption, Crop Production/Industries, Research and Development/Tech Change/Emerging Technologies, Resource /Energy Economics and Policy, Q12, Q16,
Social Distancing, Psychological Mood and Physical Activity Behavior During COVID-19 in the United States
International Journal of Exercise Science 15(5): 313-329, 2022. Social distancing, during previous epidemics, has been shown to lead to poor mental health outcomes and reduced physical activity. The purpose of the present study was to examine the relationships between self-reported psychological state and physical activity behaviors of individuals under social distancing policies during the COVID-19 pandemic. 199 individuals (29.85 ± 10.22 yrs) in the United States who had been in social distancing for 2-4 weeks participated in this study. Participants answered a questionnaire regarding feelings of loneliness, depression, anxiety, mood state, and physical activity. 66.8% of participants had depressive symptoms and 72.8% had symptoms of anxiety. Loneliness was correlated with depression (r = 0.66), trait anxiety (r = 0.36), fatigue (r = 0.38), confusion (r = 0.39), and total mood disturbance (TMD; r = 0.62). Participation in total physical activity was negatively associated with depressive symptoms (r = -0.16) and TMD (r = -0.16). State anxiety was positively associated with participation in total physical activity (r = 0.22). In addition, a binomial logistic regression was performed to predict participation in sufficient physical activity. The model explained 45% of the variance in physical activity participation and correctly categorized 77% of cases. Individuals with higher vigor scores had an increased likelihood of participating in sufficient physical activity. Loneliness was associated with negative psychological mood state. Individuals with higher feelings of loneliness, depressive symptoms, trait anxiety, and negative mood state were observed to spend less time engaged in physical activity. Higher state anxiety was positively associated with engagement in physical activity
Global Models for the Evolution of Embedded, Accreting Protostellar Disks
Most analytic work to date on protostellar disks has focused on those in
isolation from their environments. However, observations are now beginning to
probe the earliest, most embedded phases of star formation, during which disks
are rapidly accreting from their parent cores and cannot be modeled in
isolation. We present a simple, one-zone model of protostellar accretion disks
with high mass infall rates. Our model combines a self-consistent calculation
of disk temperatures with an approximate treatment of angular momentum
transport via two mechanisms. We use this model to survey the properties of
protostellar disks across a wide range of stellar masses and evolutionary
times, and make predictions for disks' masses, sizes, spiral structure, and
fragmentation that will be directly testable by future large-scale surveys of
deeply embedded disks. We define a dimensionless accretion-rotation parameter
which, in conjunction with the disk's temperature, controls the disk evolution.
We track the dominant mode of angular momentum transport, and demonstrate that
for stars with final masses greater than roughly one solar mass, gravitational
instabilities are the most important mechanism as most of the mass accumulates.
We predict that binary formation through disk fission, fragmentation of the
disk into small objects, and spiral arm strength all increase in importance to
higher stellar masses.Comment: 17 pages, 9 figures, accepted for publication in ApJ. Model updated
to better reflect simulations in the literature; discussion of key
assumptions and strategy clarifie
Efficiencies of Low-Mass Star and Star Cluster Formation
Using a quantitative model for bipolar outflows driven by hydromagnetic
protostellar winds, we calculate the efficiency of star formation assuming that
available gas is either converted into stars or ejected in outflows. We
estimate the efficiency of a single star formation event in a protostellar
core, finding 25%-70% for cores with various possible degrees of flattening.
The core mass function and the stellar initial mass function have similar
slopes, because the efficiency is not sensitive to its parameters. We then
consider the disruption of gas from a dense molecular clump in which a cluster
of young stars is being born. In both cases, we present analytical formulae for
the efficiencies that compare favorably against observations and, for clusters,
against numerical simulations. We predict efficiencies in the range 30%-50% for
the regions that form clusters of low-mass stars. In our model, star formation
and gas dispersal happen concurrently. We neglect the destructive effects of
massive stars: our results are therefore upper limits to the efficiency in
regions more massive than about 3000 Msun.Comment: 20 pages, 2 figures, accepted by Ap
An evaluation of the reliability of the foot-tapping test in a healthy sample
The foot-tapping test (FTT) can be used to assess upper motor neuron dysfunction in clinical populations. However, relatively little is known regarding the reliability or normative values of the FTT in either healthy or clinical populations. Although several different FTT methods have been used, no study to date has demonstrated the reliability or validity of FTT by comparing it across several different counting methods in healthy persons. This unfortunately limits its usefulness in medicine and research.Open Access fees paid for in whole or in part by the University of Oklahoma Libraries.Ye
Kinematic classifications of local interacting galaxies: implications for the merger/disk classifications at high-z
The classification of galaxy mergers and isolated disks is key for
understanding the relative importance of galaxy interactions and secular
evolution during the assembly of galaxies. The kinematic properties of galaxies
as traced by emission lines have been used to suggest the existence of a
significant population of high-z star-forming galaxies consistent with isolated
rotating disks. However, recent studies have cautioned that post-coalescence
mergers may also display disk-like kinematics. To further investigate the
robustness of merger/disk classifications based on kinematic properties, we
carry out a systematic classification of 24 local (U)LIRGs spanning a range of
galaxy morphologies: from isolated spiral galaxies, ongoing interacting
systems, to fully merged remnants. We artificially redshift the WiFeS
observations of these local (U)LIRGs to z=1.5 to make a realistic comparison
with observations at high-z, and also to ensure that all galaxies have the same
spatial sampling of ~900 pc. Using both kinemetry-based and visual
classifications, we find that the reliability of kinematic classification shows
a strong trend with the interaction stage of galaxies. Mergers with two nuclei
and tidal tails have the most distinct kinematic properties compared to
isolated disks, whereas a significant population of the interacting disks and
merger remnants are indistinguishable from isolated disks. The high fraction of
late-stage mergers showing disk-like kinematics reflects the complexity of the
dynamics during galaxy interactions. However, the exact fractions of
misidentified disks and mergers depend on the definition of kinematic
asymmetries and the classification threshold when using kinemetry-based
classifications. Our results suggest that additional indicators such as
morphologies traced by stars or molecular gas are required to further constrain
the merger/disk classifications at high-z.Comment: 16 pages, 5 figures, ApJ accepte
Short-Term Analysis (8 Weeks) of Social Distancing and Isolation on Mental Health and Physical Activity Behavior During COVID-19
Due to the COVID-19 pandemic, cities and states adopted social distancing, social isolation, or quarantine measurements to slow the transmission of the disease. Negative mental health outcomes including depression and anxiety have been associated with social distancing or social isolation. The purpose of the present study was to examine changes in psychological health and physical activity over an 8 week period under social distancing policies during the COVID-19 pandemic.Financial support was provided from the Office of the Vice President for Research and Partnerships and the Office of the Provost, University of Oklahoma. Open Access fees paid for in whole or in part by the University of Oklahoma Libraries.Ye
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