A Stereotaxic Atlas of the Brain of the Chick (Gallus domesticus)

Nine brains taken from chicks two weeks of age were used for the development of this atlas. Each chick was first anesthetized with an intravenous (IV) injection of Chloropent2 (1.8 ml/kg). Chicks were then perfused via the heart with 90 ml physiological saline followed by 90 ml Heidenhain\u27s3 solution. Each head was then positioned in a stereotaxic instrument as described in the previous section and three stainless steel (SS) insect pins (#2) were implanted in each brain at known coordinates. In the case of the brains used to construct the cross- sectional atlas plates, two pins were implanted horizontal to the base of the stereotaxic instrument. Each was inserted into the forebrain and the pins exited either the brainstem or the cerebellum. The third pin was inserted vertical to the base of the stereotaxic instrument. The brains used to construct the sagittal atlas plates had two pins inserted horizontally and one pin inserted vertically to the stereotaxic instrument. The horizontal pins entered the right side of the brain and exited the left side. The brains used for the horizontal plates had two pins inserted vertically and one pin horizontally. The latter entered the forebrain and exited the brainstem

Free Fridays: an alternative way to conserve energy

In February 2007, the University of Arkansas at Fayetteville (UAF) signed the President?s Climate Commitment to set a goal of becoming climate neutral. A large part of any strategy to become climate neutral includes energy conservation. In light of that, a four-day school week is proposed for UAF as an alternative energy savings possibility. This reduced schedule has been applied to K-12 schools and state government institutions, but not yet to universities. Along with numerous benefits such as energy conservation of buildings on the free day, a more effective use of time and building space and the positive emotional repercussions reported by veterans of the relatively new four-day schedule, the carbon footprint, specifically CO2 emissions, of 16 percent of the undergraduate commuters to UAF decreased by 13 percent. No consideration was given to exact calculations of energy that could be saved by shutting down classroom buildings on the extra day. However, it was found to be physically possible to collapse the current five-day school week into a four-day school week and still have extra classroom space and time to spare

Quantitative morphological analysis of submarine canyon-channel systems on the US Atlantic continental margin

Mulitbeam data of the Atlantic continental margin was used to quantify morphologic parameters of 15 canyon channels between Cape Hatteras and Georges Bank. Detailed morphologic comparison of channel parameters identified two different morphologies; Type I, U- and V-shaped with well-defined channels walls, and Type II, an incised channel bordered by terraces. Eight canyon channels are Type I whereas 7 are mixed Type I and II. Channel wall relief is the foremost differentiating parameter between Type I channels and either decreases with increased distance down-channel or increases to a maximum between the 3250 and 4000 m isobaths. Entrenchment co-occurs with steeper local seafloor slope and may reflect channel equilibrium status. The magnitude of entrenchment may be affected by riverine discharge and confinement. A north-south variation in the magnitude of channel wall relief indicates differences in margin processes. Longitudinal profiles of the channels also show a north-south relationship that reflects regional slopes

Grain yield and groat-protein percentage relationships in oats (Avena sativa L)

Relationships between groat-protein percentage (PP), grain yield (GYD), and protein yield (PYD) of oats were studied using F(,2)-derived lines in the F(,3) and F(,4) populations from 27 matings between high-protein and high-yield lines. The high-protein parents included (a) selections from an Avena sativa bulk, (b) selections from three-way matings in which an initial parent was A. sterilis, and (c) commercial cultivars. The high-yield parents were derived from backcross populations involving A. sterilis donor parents;Significant genetic variability existed among F(,2)-derived lines for PP, GYD and PYD in all matings except one for PP. Progeny means and midparent values for PP, GYD, and PYD in 5, 12, and 16 matings, respectively suggested additive gene action was operating for these traits. Design II analyses of 23 matings indicated the importance of additive effects for GYD genes and additive and nonadditive effects for PP and PYD genes. Mean heritabilities on a plot basis for the matings ranged from 0.11-0.63 for PP, 0.11-0.43 for GYD, and 0.10-0.44 for PYD;PP had a highly significant negative correlation with GYD (-0.33**) overall, but in five matings, these traits were not significantly correlated. Overall, PP had a small significant negative correlation with PYD (-0.09**) and PYD and GYD had a high positive association (0.98**). F(,2)-derived lines with both high PP and high GYD were obtained;High transgressive segregates occurred in two matings for PP, in nine for GYD, and in 14 for PYD. These high transgressive segregates in many cases were probably due to epistatic interactions;Comparisons of high transgressive segregates for PYD with their mating midparent values showed that increases in PYD were due to either increases in GYD only or concurrent increases in PP and GYD. In four matings, high transgressive segregates for PYD were due to increases in both PP and GYD, with up to 57% of the increase due to PP. In 12 matings, high transgressive segregates for PYD were due to increases in GYD alone;Specific genetic combinations of high-protein and high-yield parents were important in determining which matings produced the highest PPs, GYDs, and PYDs. These traits are moderately heritable, so genetic variability for both PP and GYD should be exploited in selecting for high PYD

Encapsulation of Cs/Sr contaminated clinoptilolite in geopolymers produced from metakaolin

The encapsulation of caesium (Cs) and strontium (Sr) contaminated clinoptilolite in Na and K based metakaolin geopolymers is reported. When Cs or Sr loaded clinoptilolite is mixed with a metakaolin geopolymer paste, the high pH of the activating solution and the high concentration of ions in solution cause ion exchange reactions and dissolution of clinoptilolite with release of Cs and Sr into the geopolymer matrix. The leaching of Cs and Sr from metakaolin-based geopolymer has therefore been investigated. It was found that Na-based geopolymers reduce leaching of Cs compared to K-based geopolymers and the results are in agreement with the hard and soft acids and bases (HSAB) theory. Cs ions are weak Lewis acids and aluminates are a weak Lewis base. During the formation of the geopolymer matrix Cs ions are preferentially bound to aluminate phases and replace Na in the geopolymer structure. Sr uptake by Na-geopolymers is limited to 0.4 mol Sr per mole of Al and any additional Sr is immobilised by the high pH which causes precipitation of Sr as low solubility hydroxide and carbonate phases. There was no evidence of any other phases being formed when Sr or Cs are added to metakaolin geopolymers

A characterization of well-dominated Cartesian products

A graph is well-dominated if all its minimal dominating sets have the same cardinality. In this paper we prove that at least one factor of every connected, well-dominated Cartesian product is a complete graph, which then allows us to give a complete characterization of the connected, well-dominated Cartesian products if both factors have order at least $2$. In particular, we show that $G\,\Box\,H$ is well-dominated if and only if $G\,\Box\,H = P_3 \,\Box\,K_3$ or $G\,\Box\,H= K_n \,\Box\,K_n$ for some $n\ge 2$.Comment: 17 page