Fermi Surfaces of Diborides: MgB2 and ZrB2

We provide a comparison of accurate full potential band calculations of the Fermi surfaces areas and masses of MgB2 and ZrB2 with the de Haas-van Alphen date of Yelland et al. and Tanaka et al., respectively. The discrepancies in areas in MgB2 can be removed by a shift of sigma-bands downward with respect to pi-bands by 0.24 eV. Comparison of effective masses lead to orbit averaged electron-phonon coupling constants lambda(sigma)=1.3 (both orbits), lambda(pi)=0.5. The required band shifts, which we interpret as an exchange attraction for sigma states beyond local density band theory, reduces the number of holes from 0.15 to 0.11 holes per cell. This makes the occurrence of superconductivity in MgB2 a somewhat closer call than previously recognized, and increases the likelihood that additional holes can lead to an increased Tc.Comment: 7 pages including 4 figure

Electronic structure of CaCuO2 from the B3LYP hybrid density functional

Published versio

The relational shift in urban ecology: from place and structures to multiple modes of coproduction for positive urban futures

This perspective emerged from ongoing dialogue among ecologists initiated by a virtual workshop in 2021. A transdisciplinary group of researchers and practitioners conclude that urban ecology as a science can better contribute to positive futures by focusing on relationships, rather than prioritizing urban structures. Insights from other relational disciplines, such as political ecology, governance, urban design, and conservation also contribute. Relationality is especially powerful given the need to rapidly adapt to the changing social and biophysical drivers of global urban systems. These unprecedented dynamics are better understood through a relational lens than traditional structural questions. We use three kinds of coproduction—of the social-ecological world, of science, and of actionable knowledge—to identify key processes of coproduction within urban places. Connectivity is crucial to relational urban ecology. Eight themes emerge from the joint explorations of the paper and point toward social action for improving life and environment in urban futures

Chirality and Symmetry Breaking in a discrete internal Space

In previous papers the permutation group S_4 has been suggested as an ordering scheme for elementary particles, and the appearance of this finite symmetry group was taken as indication for the existence of a discrete inner symmetry space underlying elementary particle interactions. Here it is pointed out that a more suitable choice than the tetrahedral group S_4 is the pyritohedral group A_4 x Z_2 because its vibrational spectrum exhibits exactly the mass multiplet structure of the 3 fermion generations. Furthermore it is noted that the same structure can also be obtained from a primordial symmetry breaking S_4 --> A_4. Since A_4 is a chiral group, while S_4 is achiral, an argument can be given why the chirality of the inner pyritohedral symmetry leads to parity violation of the weak interactions.Comment: 42 pages, 3 table

Factors influencing rate of gain, amount of feed consumed and carcass grade

This is the second trial to study the effect of differences which can be observed in feed calves classified as good to choice. The two lots in this trial were sorted from the 100 range-bred heifer calves purchased last November for feeding experiments at this station. This was a very uniform shipment of calves with no plain ones in the group. Sorting for the two lots of calves was made on apparent differences in capacity for feed, chest room, muscling, bone, and general appearance. The individual calves also were graded by using a standard feeder chart

Fattening heifers for the summer or early fall market.

The purpose of this experiment is to develop a desirable system or systems of fattening heifer calves similar to the Deferred Full Feeding system for steer calves. The system developed for good quality steer calves consisted of three phases (1) producing 225 to 250 pounds of gain during the winter, which usually require the feeding of four to five pounds of grain per head daily; (2) grazing 90 days without grain; (3) full feeding 100 days in the dry lot. The results of several prior trials at this station with heifer calves were considered before planning this experimen

Comparison of Hereford steers sired by small, medium and large size bulls.

The Kansas, Oklahoma, and Ohio Agricultural Experiment Stations are cooperating in this study, which is supported by grants from the American Hereford Association. In October, 1948, each station received 96 steer calves from the following commercial herds: Bar 13 Ranch, P. K. Ranch, and O. M. Wallop, Sheridan, Wyoming; and M. C. Simpson, Volborg, Montana. These steer calves, sired by small, medium, and large size bulls are being compared at each of the three stations under three standard systems of feeding and management. System I involves immediate full feeding for 225 days. System II represents a deferred full feeding program in which the steers calves are wintered well, grazed without grain from May 1 to August 1, and then full fed in dry lot 100 days. System III has for its objective the production of two-year old grass fat steers without the feeding of grain. Phases under this system include: wintering as calves without grain; grazing as yearlings a full season without supplemental feed; wintering as yearlings without grain; grazing as two-year olds without supplemental feed and selling as slaughter cattle directly off pasture