3,932 research outputs found
Parallel developmental genetic features underlie stickleback gill raker evolution.
BackgroundConvergent evolution, the repeated evolution of similar phenotypes in independent lineages, provides natural replicates to study mechanisms of evolution. Cases of convergent evolution might have the same underlying developmental and genetic bases, implying that some evolutionary trajectories might be predictable. In a classic example of convergent evolution, most freshwater populations of threespine stickleback fish have independently evolved a reduction of gill raker number to adapt to novel diets. Gill rakers are a segmentally reiterated set of dermal bones important for fish feeding. A previous large quantitative trait locus (QTL) mapping study using a marine × freshwater F2 cross identified QTL on chromosomes 4 and 20 with large effects on evolved gill raker reduction.ResultsBy examining skeletal morphology in adult and developing sticklebacks, we find heritable marine/freshwater differences in gill raker number and spacing that are specified early in development. Using the expression of the Ectodysplasin receptor (Edar) gene as a marker of raker primordia, we find that the differences are present before the budding of gill rakers occurs, suggesting an early change to a lateral inhibition process controlling raker primordia spacing. Through linkage mapping in F2 fish from crosses with three independently derived freshwater populations, we find in all three crosses QTL overlapping both previously identified QTL on chromosomes 4 and 20 that control raker number. These two QTL affect the early spacing of gill raker buds.ConclusionsCollectively, these data demonstrate that parallel developmental genetic features underlie the convergent evolution of gill raker reduction in freshwater sticklebacks, suggesting that even highly polygenic adaptive traits can have a predictable developmental genetic basis
The Effects of Diet and Cooler Aging on Specific Flavor Notes in Beef
Crossbred steers (n = 64) were grazed on warm- or cool-season grass-dominated pastures, without or with energy supplementation of wet distillers grains with solubles (WDGS), and were finished on a corn-based diet with or without 35% WDGS. Finishing on corn increased desirable flavor notes and decreasedundesirable flavor notes in both L. dorsi and B. femoris steaks. In addition, grazing on warm-season grasses increased the prevalence of undesirable flavors but was often dissipated by the addition WDGS supplementation. Longer aging periods tended to increase the prevalence of undesirable flavors, especially in B. femoris steaks. It is recommended producers provide WDGS supplementation, especially when grazing on warm-season grasses, and finish on an all corn diet in order to create a favorable flavor palate
Roughrider... A Winterhard, High Yielding Hard Red Winter Wheat Variety
Roughrider is higher yielding and more lodging resistant than either Froid or Winoka, the two most popular winter wheat varieties in North Dakota. It is heavier in test weight, earlier maturing and shorter than Froid. Its winterhardiness is similar to Froid and superior to Winoka. The name "Roughrider" was taken from the association with President Theodore Roosevelt, who ranched in western North Dakota where this variety is well adapted
Effect of Enogen Feed Corn Inclusion in Conventional and Natural Finishing Cattle Diets
Increasing the extent of starch digestibility during finishing could allow producers to improve cattle efficiency. A finishing performance study was conducted to determine the effect of Enogen Feed Corn inclusion as dry-rolled corn and corn silage in comparison to a control corn hybrid within natural and conventional feeding programs for heifers and steers. Cattle in the conventional feeding program received implants and the ration included feed additives, while cattle on the natural program were not implanted and the ration did not contain feed additives. The inclusion of Enogen Feed Corn had no impact on steer or heifer finishing performance. The use of implants and feed additives in the conventional feeding program increased hot carcass weight 12.2% in steers and 7.0% in heifers. When compared to cattle in the natural program, feeding cattle in a conventional program improved feed conversion by 19.4% in steers and 13.0% in heifers
Anticipatory Resilience Bringing Back the Future into Urban Planning and Knowledge Systems
Anticipatory thinking is a critical component in urban planning practices and knowledge systems in an era of unpredictability and conflicting expectations of the future. This chapter introduces “anticipatory resilience” as a futures-oriented knowledge system that intentionally addresses uncertain climate conditions and explores alternative, desirable future states. It suggests a portfolio of tools suitable for building long-term foresight capacity in urban planning. Examples of knowledge systems interventions are presented to explore the trade-offs, constraints, possibilities, and desires of diverse future scenarios co-generated in settings with people that hold different perspectives, knowledge, and expectations
The resistance experiments: Morality, authority and obedience in Stanley Milgram's account
The paper seeks to re‐conceptualize Stanley Milgram's (in)famous experiments on willing obedience by drawing solely on Milgram's own contemporary account. It identifies a substantial incongruence between the findings Milgram presented (i.e., his description of the experiments) and the meaning he imputed to them (i.e., his interpretation of the exper iments). It argues that instead of operationalizing the concepts he claimed to operationalize – legitimate authority, embodied morality and willing obedience –, Milgram's description suggests that the operative forces in the experiments were an illegitimate authority and acts which in effect collude with that authority. As a result, the paper concludes that what the experimental findings represented was not so much obedience out of choice, but out of coercion. Thus, the paper seeks to redirect the conceptual‐moral focus of the findings from the participants who “shockingly” obeyed to those who managed to resist the coercive force of the total experimental situation
Effects of Corn Processing and Silage Inclusion in Feedlot Diets on Steer Performance
A feelot study compared the effects of corn silage inclusion on steer performance and carcass characteristics withing dry-rolled corn diets and steam-flaked corn diets. Treatments included four corn silage inclusions as 0, 15, 30, 45% of dry matter in both steam-flaked corn and dry-rolled corn base diets. Feeding a steam-flaked based corn diet increased average daily gain by 7.8% and improved feed conversion by 6.8% when compared to steers fed a dry-rolled corn diet. As corn silage inclusion increased, feed conversion increased linearly. When fed to the same days on feed carcass adjusted final body weight, hot carcass weight, and average daily gain responded quadratically: steers fed 15% and 30% corn silage gained faster and were heavier than steers fed 0% or 45% corn silage. Feeding steam-flaked corn improved gain and feed conversion compared to dry-rolled corn. Regardless of corn processing method, including corn silage in the diet at 15 or 30% of dry matter maximized gain but as expected, feed conversion was lowest with no roughage
Ferromagnetism in the Mott insulator Ba2NaOsO6
Results are presented of single crystal structural, thermodynamic, and
reflectivity measurements of the double-perovskite Ba2NaOsO6. These
characterize the material as a 5d^1 ferromagnetic Mott insulator with an
ordered moment of ~0.2 Bohr magnetons per formula unit and TC = 6.8(3) K. The
magnetic entropy associated with this phase transition is close to Rln2,
indicating that the quartet groundstate anticipated from consideration of the
crystal structure is split, consistent with a scenario in which the
ferromagnetism is associated with orbital ordering.Comment: 5 pages, 5 figures, added reference
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