Dependence of nuclear binding on hadronic mass variation

We examine how the binding of light ($A\leq 8$) nuclei depends on possible variations of hadronic masses, including meson, nucleon, and nucleon-resonance masses. Small variations in hadronic masses may have occurred over time; the present results can help evaluate the consequences for big bang nucleosynthesis. Larger variations may be relevant to current attempts to extrapolate properties of nucleon-nucleon interactions from lattice QCD calculations. Results are presented as derivatives of the energy with respect to the different masses so they can be combined with different predictions of the hadronic mass-dependence on the underlying current-quark mass $m_q$. As an example, we employ a particular set of relations obtained from a study of hadron masses and sigma terms based on Dyson-Schwinger equations and a Poincar\'{e}-covariant Faddeev equation for confined quarks and diquarks. We find that nuclear binding decreases moderately rapidly as the quark mass increases, with the deuteron becoming unbound when the pion mass is increased by $\sim$60% (corresponding to an increase in $X_q=m_q/\Lambda_{QCD}$ of 2.5). In the other direction, the dineutron becomes bound if the pion mass is decreased by $\sim$15% (corresponding to a reduction of $X_q$ by $\sim$30%). If we interpret the disagreement between big bang nucleosynthesis calculations and measurements to be the result of variation in $X_q$, we obtain an estimate $\delta X_q/X_q=K \cdot (0.013 \pm 0.002)$ where $K \sim 1$ (the expected accuracy in $K$ is about a factor of 2). The result is dominated by $^7$Li data.Comment: 28 pages including 3 figures v2:additional citations/acknowledgments adde

Unitary interpolants and factorization indices of matrix functions

For an $n\times n$ bounded matrix function $\Phi$ we study unitary interpolants $U$, i.e., unitary-valued functions $U$ such that $\hat U(j)=\hat\Phi(j)$, $j<0$. We are looking for unitary interpolants $U$ for which the Toeplitz operator $T_U$ is Fredholm. We give a new approach based on superoptimal singular values and thematic factorizations. We describe Wiener--Hopf factorization indices of $U$ in terms of superoptimal singular values of $\Phi$ and thematic indices of $\Phi-F$, where $F$ is a superoptimal approximation of $\Phi$ by bounded analytic matrix functions. The approach essentially relies on the notion of a monotone thematic factorization introduced in [AP]. In the last section we discuss hereditary properties of unitary interpolants. In particular, for matrix functions $\Phi$ of class H^\be+C we study unitary interpolants $U$ of class $QC$.Comment: 20 page

Rabbit behaviour research in Australia and its relevance in control operations

Research in Australia on the behaviour of wild rabbits has provided a basis for improvements in the tactics and strategy of control. As the warren is a central focus for growth and survival of a population, a program for effective control or eradication should aim at making the warren unavailable to rabbits. Enclosure studies of behaviour suggested that poisoning would be much more effective when carried out in the non-breeding season. This has been confirmed in field trials. The behavioural importance of the odour-producing inguinal, submandibular, and anal glands is emphasized. It is suggested that further studies of these glands may provide insights for the development of repellents or attractants

Computer circuit card puller

The invention generally relates to hand tools, and more particularly to an improved device for facilitating removal of printed circuit cards from a card rack characterized by longitudinal side rails arranged in a mutually spaced parallelism and a plurality of printed circuit cards extended between the rails of the rack

Magnetic and magnetoelectric studies in pure and cation doped BiFeO3

We report magnetic and magnetoelectric studies on BiFeO3 and divalent cation (A) suvtitute Bi0.7A0.3FeO3 (A = Sr,Ba, and Sr0.5Ba0.5). It is shown that the rapid increase of magnetization at the Neel temperature (TN = 642 K) is suppressed in the co-doped compound A = Sr0.5Ba0.5. All the divalent subtituted compounds show enhanced magnetization and hysteresis loop. Both longitudinal and transverse magnetoelectric coefficients were measured using the dynamical lock-in technique. The co-doped compound shows the highest magnetoelectric coefficient at room temperature although it is not the compound with the highest saturation magnetization. It is found that as the size of the A-site cation increses, the transverse magnetoelectric coeffient increases and exceeds the longitudinal magnetoelectric coefficient. It is suggested that changes in magnetic domain structure and magnetostriction are possible reasons for the observed changes in the magnetoelectric coefficients.Comment: 16 pages, 6 figur

Electrical, magnetic, magnetodielectric and magnetoabsorption studies in multiferroic GaFeO3

We report electrical, magnetic, magnetodielectric and magnetoabsorption properties of a polycrystalline GaFeO3. The resistivity measurement shows that the sample is highly insulating below 200 K and the resistivity above 200 K obey the Arrhenius law with an activation energy of Ea = 0.67 eV. An anomaly occurs in the temperature dependence of permittivity (e) near the ferrimagnetic transition temperature (TC = 228 K) in a zero magnetic field and it is suppressed under H = 60 mT which indicates a possible magnetoelectric coupling in GaFeO3 with a fractional change of de/e = -1.8% at 60 mT around TC. The coercivity (HC) of the sample increases dramatically with lowering temperature below 200 K from 0.1 T at 200 K to 0.9 T at 5 K. Magnetoabsorption was studied with a LC resonance technique and we found a close correlation between the shift in the resonance frequency due to applied magnetic field and the coercive field measured using dc magnetization measurements. Our results obtained with multiple techniques suggest that GaFeO3 is an interesting ferrimagnet with potential applications in future multiferroic devices.Comment: 22 pages, 6 figures. submitted to J. Appl. Phy