Dynamical reduction of the dimensionality of exchange interactions and the "spin-liquid" phase of κ\kappa-(BEDT-TTF)2X_2X

We show that the anisotropy of the effective spin model for the dimer Mott insulator phase of $\kappa$-(BEDT-TTF)$_2X$ salts is dramatically different from that of the underlying tight-binding model. Intra-dimer quantum interference results in a model of coupled spin chains, where frustrated interchain interactions suppress long-range magnetic order. Thus, we argue, the "spin liquid" phase observed in some of these materials is a remnant of the Tomonaga-Luttinger physics of a single chain. This is consistent with previous experiments and resolves some outstanding puzzles. An erratum [Phys. Rev. Lett. 120, 199901 (2018).] is added as an appendix.Comment: Accepted by PRL, 6 pages, 5 figure

Towards mechanomagnetics in elastic crystals: insights from [Cu(acac)2_2]

We predict that the magnetic properties of \cuacac, an elastically flexible crystal, change dramatically when the crystal is bent. We find that unbent \cuacac\ is an almost perfect Tomonaga-Luttinger liquid. Broken-symmetry density functional calculations reveal that the magnetic exchange interactions along the chains is an order of magnitude larger than the interchain exchange. The geometrically frustrated interchain interactions cannot magnetically order the material at any experimentally accessible temperature. The ordering temperature ($T_N$), calculated from the chain random phase approximation, increases by approximately 24 orders of magnitude when the material is bent. We demonstrate that geometric frustration both suppresses $T_N$ and enhances the sensitivity of $T_N$ to bending. In \cuacac, $T_N$ is extremely sensitive to bending, but remains too low for practical applications, even when bent. Partially frustrated materials could achieve the balance of high $T_N$ and good sensitivity to bending required for practical applications of mechanomagnetic elastic crystals

Computer optimization techniques for NASA Langley's CSI evolutionary model's real-time control system

The evolution and optimization of a real-time digital control system is presented. The control system is part of a testbed used to perform focused technology research on the interactions of spacecraft platform and instrument controllers with the flexible-body dynamics of the platform and platform appendages. The control system consists of Computer Automated Measurement and Control (CAMAC) standard data acquisition equipment interfaced to a workstation computer. The goal of this work is to optimize the control system's performance to support controls research using controllers with up to 50 states and frame rates above 200 Hz. The original system could support a 16-state controller operating at a rate of 150 Hz. By using simple yet effective software improvements, Input/Output (I/O) latencies and contention problems are reduced or eliminated in the control system. The final configuration can support a 16-state controller operating at 475 Hz. Effectively the control system's performance was increased by a factor of 3

Feed intake pattern, behaviour, rumen characteristics and blood metabolites of finishing beef steers offered total mixed rations constituted at feeding or ensiling

peer-reviewedTwo experiments were undertaken. In Experiment 1, behaviour, intake pattern and blood metabolites, were recorded for steers offered total mixed rations (TMR) based on grass silage and concentrates, and constituted either at ensiling (E-TMR) or feedout (F-TMR). Fourteen continental crossbred steers (mean starting weight 505 (s.d. 41.5) kg) were assigned to each of the following eight treatments: grass silage offered ad libitum (SO), E-TMR diets constituted in approximate dry matter (DM) ratios of grass:concentrates of 75:25 (EL), 50:50 (EM) and 25:75 (EH), F-TMR diets constituted in approximate DM ratios of grass silage:concentrates of 75:25 (FL), 50:50 (FM) and 25:75 (FH), and finally concentrates ad libitum (AL). Total DM intake increased linearly (P < 0.001) and the time spent eating and ruminating decreased linearly (P < 0.001) with increasing concentrate proportion. Animals on the F-TMR diets had higher total DM intakes (P < 0.05) and plasma glucose (P < 0.05) and urea (P < 0.001) concentrations than animals on the corresponding E-TMR diets. No effect of method of feed preparation on intake pattern or behaviour was recorded. In Experiment 2, four ruminally cannulated Holstein-Friesian steers of mean initial live weight 630 (s.d. 23.2) kg were used to evaluate rumen characteristics for four of the above diets (FL, EL, FH and EH) in a 4 × 4 latin square design. Higher concentrate diets resulted in lower rumen pH (P < 0.05), higher lactic acid (P < 0.001) and ammonia (P < 0.05) concentrations and lower acetate:propionate (P < 0.05). F-TMR was associated with a higher (P < 0.05) rumen volatile fatty acid concentration but no difference in other rumen fermentation characteristics compared to E-TMR. Concentrate proportion and method of feed preparation had no effect (P > 0.05) on rumen pool sizes but animals consuming the high concentrate diet had a faster (P < 0.05) rumen passage rate of NDF than animals on the low concentrate diet.B. Cummins was in receipt of a Teagasc Walsh Fellowship

Conservation characteristics of grass and dry sugar beet pulp co-ensiled after different degrees of mixing

peer-reviewedThe objective of this experiment was to quantify the effects of the degree of mixing of dry molassed sugar beet pulp (BP) with grass on silage conservation characteristics. Herbage from a timothy (Phleum pratense) sward was precision chopped and treated with a formic acid based additive (3 l/t grass). Units of 50 kg grass, without or with 2.5kg BP were randomly allocated among four replicates on each of seven treatments. The treatments were (1) no BP (NONE), (2) BP evenly mixed through the grass (EVEN), (3) BP evenly mixed through the lower 25 kg grass (LOWH), (4) BP evenly mixed through the lower 12.5 kg grass (LOWQ), (5) 0.625 kg BP mixed through the top 25 kg grass and 1.875 kg SBP mixed through the lower 25 kg grass (25/75), (6) BP placed in 0.5 kg layers beneath each 10 kg grass (LAYR), and (7) BP placed in a single layer under all of the grass (BOTM). Laboratory silos were filled and sealed, and stored at 15 °C for 163 days. Effluent was collected and weighed from each silo throughout the ensilage period. At opening, silage composition and aerobic stability measurements were made. Total outflow of effluent was reduced (P<0.001) by the addition of BP; LAYR had a greater effect (P<0.001) than any of the other treatments. Effluent dry matter (DM) concentration was highest (P<0.05) for BOTM and lowest (P<0.01) for NONE. All treatments underwent similar lactic-acid dominant fermentations. Incorporation of BP with grass increased silage DM concentration (P<0.001), in vitro DM digestibility (P<0.05) and water soluble carbohydrate (P<0.001) concentration and reduced acid detergent fibre (P<0.001) concentration. Aerobic stability was similar across treatments and aerobic deterioration at 192 h was higher (P<0.05) for LOWQ, 25/75, LAYR and BOTM than for NONE. In conclusion, the incorporation of BP increased silage DM digestibility but had relatively little effect on fermentation or aerobic stability. Placing BP in layers gave the largest and most sustained restriction in effluent output.B. Cummins acknowledges receipt of a Walsh Fellowship provided by Teagasc

Effects of breed type, silage harvest date and pattern of offering concentrates on intake, performance and carcass traits of finishing steers

peer-reviewedThe objective of this experiment was to investigate the effects and interactions of breed type, silage harvest date and pattern of offering concentrates on intake, performance and carcass traits of finishing steers. Seventy-two steers (36 Friesian and 36 beef cross) were blocked on weight within breed type and assigned to a pre-experimental slaughter group or to one of 4 dietary treatments in a 2 (breed type) 2 (early- or late- cut silage) 2 (flat rate or varied pattern of offering concentrates) factorial arrangement of treatments. The flat-rate feeding pattern was silage ad libitum plus 5 kg concentrates per head daily to slaughter. The varied feeding pattern was silage only for 79 days followed by concentrates ad libitum to slaughter. All animals were slaughtered together after 164 days when the groups on the two feeding patterns had consumed the same total quantity of concentrates. Friesians had a higher (P < 0.001) silage dry matter (DM) intake and a higher (P < 0.01) total DM intake than the beef crosses. Live-weight gain was similar for both breed types but the beef-cross animals had a higher (P < 0.001) kill-out proportion, higher (P < 0.01) carcass gain, and better (P < 0.001) carcass conformation than the Friesians. The beef-cross type also had a higher (P < 0.001) proportion of muscle and a lower (P < 0.001) proportion of bone in the carcass. Silage harvest date had no effect on silage or total DM intakes but the early-cut silage did result in higher (P < 0.01) carcass gain. Animals on the varied feeding pattern consumed less (P < 0.01) silage DM and less (P < 0.001) total DM than those on the flat rate feeding pattern. Live-weight gain and carcass gain were similar for the two feeding patterns. It is concluded that Friesians had a higher intake, but had lower carcass gain than the beef-cross type. Animals on the early-cut silage had higher carcass gain than those on the late-cut silage. The varied feeding pattern resulted in lower DM intake but efficiency of feed energy utilisation was similar for both feeding patterns. Interactions were generally not statistically significant

Defining novel mediators and mechanisms of neural microvasculature permeability

The microvasculature of the nervous system is exceptionally specialised and its restrictive nature implied by its moniker, blood-brain barrier (BBB), with blood-retinal barrier (BRB) relating to the retinal vasculature. The importance of these barriers is evident during disease states where their functionality is compromised, as in diabetic retinopathy (DR). Due to the complexity of circulating and local mediators with signalling potential at these barriers, and the lack of adequate treatment for some disorders with microvasculature disturbances, there is scope for enriching the knowledge base in this area. With DR as a starting point, it was hypothesised that there were factors other than vascular endothelial growth factor (VEGF) involved in disease progression. It was shown that a bioactive lipid, lysophosphatidylcholine (LPC), enhanced junctional permeability at both the BBB and BRB, doing so via VEGF receptor 2 (VEGFR2) activation thus implicating a transactivation mechanism. It followed that such a mechanism might be involved in the actions of other vascular mediators, bradykinin (BK), lysophosphatidic acid (LPA), thrombin (THR) and TNF-α, and the data shown suggests that this may be the case for more than one of the mediators tested. The former set of data also indicated the presence of transcellular transport across the BBB, the existence of which is highly contested within the literature, and a subsequent aim, investigating the extent of transcytosis for a range of pertinent mediators, was addressed, and for which novel multicellular BBB models were developed and characterised. Finally, in connection with the vesicular process observed for mediators tested, VE-Cadherin (VEC) internalisation, hypothetically to vesicular structures, was tested following ICAM-1 adhesion, as it is key to leukocyte migration via VEC modulation. This cumulative work demonstrates novel roles for LPC-induced permeability, VEGFR2 transactivation by vasoactive stimuli, transcytosis and VEC internalisation at the BBB

H.B. 635: Use on Use Sales Tax Exemption Reenacted

In May of 1978, the 112th General Assembly enacted House Bill 635, amending section 5739.02 of the Ohio Revised Code. The bill added subsection (B)(25), a use on use exemption from the sales tax.\u27 The ultimate effect of this exemption is to relieve certain sales from the sales tax. This exception is known as the direct use sales tax exception. Because the definition of retail sale excludes the direct use transaction, no sales tax is imposed. These two definitions appear in the definitional section of the sales tax chapter. The general sales tax levying provision, section 5739.02, lists numerous exemptions from the sales tax. The newest exemption, added by House Bill 635, exempts from sales tax any sale to persons engaged in manufacturing … of tangible personal property for use or consumption directly in the production by manufacturing … of other tangible personal property for use or consumption directly in the production of tangible personal property for sale by manufacturing … and of material and parts for incorporation into any such tangible personal property for use or consumption in production. This is known as the use on use exemption because the sales of material which will be directly used in the production of a product, which will later be used to produce a product for sale, are now exempt from any sales tax. Note the close similarity of language between the direct use exception and the use on use exemption. … There appears to be no sound justification for exempting the purchase of a machine used to produce a product for retail sale, but taxing the purchase of materials used to build a machine for the same purpose. The use on use exemption removes one artificial economic cost from the decision whether to purchase or build items used to produce products for retail sale

Regulation of Employee Welfare Benefit Plans: The Scope of ERISA\u27s Preemption and the State Power to Regulate Insurance

In 1974 Congress enacted the Employee Retirement Income Security Act, which was hailed as landmark social legislation in the area of pension and welfare plan reform. It has been characterized as the greatest development in the life of the American worker since social security. ERISA was enacted to remedy many of the defects and problems associated with employee pension and welfare benefit plans. A primary objective was to strengthen the private employee benefit plan system to provide for the retirement and financial security of employees and their families and, no less importantly, to encourage the growth of this system. Many employees were losing anticipated pension and welfare benefits because of the lack of vesting provisions, the financial instability of benefit plans, imprudent investment by plan trustees, theft of plan assets, and plan termination without adequate funds to cover accrued liabilities. ERISA is a lengthy and complex regulatory framework setting out standards for welfare and pension plan reporting and disclosure, fiduciary responsibility, administration and enforcement. … ERISA does not provide for the substantive regulation of benefit requirements for welfare plans. The result is a statutory vacuum for welfare plans. Some states have attempted to fill this vacuum by enacting legislation requiring that certain types of benefits be included in group health insurance which is purchased by employee welfare benefit plans, or by indirectly regulating welfare benefit plans. Many states view this legislation as socially progressive because it is designed to provide increased benefits and protect against illusory benefits. This policy, however, can produce the opposite of the expected result in some cases and is counter-productive to the goal of national uniformity sought by Congress. To eliminate conflict with state and local regulation, ERISA grants control to the federal government over the establishment, conduct, supervision, and regulation of employee benefit plans