A recommended method for detecting salmonellae in composted biosolids

It has been found in Australia and in the United States that composting does not always result in the complete removal of salmonellae from biosolids. It is therefore likely that monitoring of composted Biosolids for salmonellae will be required in Australia to ensure the safety of biosolids products. At present rapid methods of detection such as PCR and ELISA are not sufficiently developed to monitor environmental samples. The relative efficiency of various culture methods for detecting salmonellae in composted biosolids was therefore investigated. On the basis of the results a presence/absence method is recommended for the detection of salmonellae in biosolids products. The recommended technique involves pre-enrichment of samples, followed by enrichment in Rappaport-Vassiliadis and mannitol selenite enrichment broths, and isolation on lysine mannitol glycerol agar

The Neutrino Response of Low-Density Neutron Matter from the Virial Expansion

We generalize our virial approach to study spin-polarized neutron matter and the consistent neutrino response at low densities. In the long-wavelength limit, the virial expansion makes model-independent predictions for the density and spin response, based only on nucleon-nucleon scattering data. Our results for the neutrino response provide constraints for random-phase approximation or other model calculations, and we compare the virial vector and axial response to response functions used in supernova simulations. The virial expansion is suitable to describe matter near the supernova neutrinosphere, and this work extends the virial equation of state to predict neutrino interactions in neutron matter.Comment: 8 pages, 5 figures, minor additions, to appear in Phys. Lett.

The Virial Equation of State of Low-Density Neutron Matter

We present a model-independent description of low-density neutron matter based on the virial expansion. The virial equation of state provides a benchmark for all nuclear equations of state at densities and temperatures where the interparticle separation is large compared to the thermal wavelength. We calculate the second virial coefficient directly from the nucleon-nucleon scattering phase shifts. Our results for the pressure, energy, entropy and the free energy correctly include the physics of the large neutron-neutron scattering length. We find that, as in the universal regime, thermodynamic properties of neutron matter scale over a wide range of temperatures, but with a significantly reduced interaction coefficient compared to the unitary limit.Comment: 7 pages, 6 figures, minor revisions, to appear in Phys. Lett.

Resequencing And Nucleotide Variation Of Sucrose Synthase (Nmsusy1) Gene In A Tropical Timber Tree Neolamarckia Macrophylla

Sucrose synthase (SuSy) is a key enzyme that catalyses the reversible synthesis and degradation of sucrose. It provides greater impact in regulating the photosynthetic processes and environmental stresses in plants. Thus, the nucleotide variation of partial NmSusy1 genomic DNAs (750 bp) generated through PCR amplification was examined in this study, and this followed by resequencing from 15 selected Neolamarckia macrophylla clones. The consensus sequences were aligned to detect the presence of single nucleotide polymorphisms (SNPs). In total, five SNPs were detected at nucleotide 1, 2, 34, 35 and 397. Of these, four SNPs were located at the predicted coding region while one SNP was located at the predicted non-coding region. Interestingly, one single base pair InDel polymorphism was also detected at nucleotide 17. On average, one SNP at every 150 bp was detected based on the 15 NmSusy1 sequences. There was one non-synonymous mutation detected, whereby amino acid glutamic acid (E) was replaced by arginine (R) in one of the 15 samples tested. This non-synonymous SNP might change the structural, functional or biochemical properties of the enzyme being produced and therefore possibly lead to changes in phenotypic characteristic of the trees. Overall, this study has demonstrated that resequencing is an effective technique for classifying molecular diversity or nucleotide variation in the Susy gene of N. macrophylla. Those SNPs, once validated, could potentially be used as a tool in marker-assisted selection (MAS) that enables more precise and accurate in the selection and prediction of yield or performance at the early developmental stages, such as at the seedling stage

Effective non-linear dynamics of binary condensates and open problems

We report on a recent result concerning the effective dynamics for a mixture of Bose-Einstein condensates, a class of systems much studied in physics and receiving a large amount of attention in the recent literature in mathematical physics; for such models, the effective dynamics is described by a coupled system of non-linear Sch\"odinger equations. After reviewing and commenting our proof in the mean field regime from a previous paper, we collect the main details needed to obtain the rigorous derivation of the effective dynamics in the Gross-Pitaevskii scaling limit.Comment: Corrected typos, updated reference

Instabilities in a Two-Component, Species Conserving Condensate

We consider a system of two species of bosons of equal mass, with interactions $U^{a}(|x|)$ and $U^{x}(|x|)$ for bosons of the same and different species respectively. We present a rigorous proof -- valid when the Hamiltonian does not include a species switching term -- showing that, when $U^{x}(|x|)>U^{a}(|x|)$, the ground state is fully "polarized" (consists of atoms of one kind only). In the unpolarized phase the low energy excitation spectrum corresponds to two linearly dispersing modes that are even a nd odd under species exchange. The polarization instability is signaled by the vani shing of the velocity of the odd modes.Comment: To appear in Phys. Rev.

Cluster Formation and The Virial Equation of State of Low-Density Nuclear Matter

We present the virial equation of state of low-density nuclear matter composed of neutrons, protons and alpha particles. The virial equation of state is model-independent, and therefore sets a benchmark for all nuclear equations of state at low densities. We calculate the second virial coefficients for nucleon-nucleon, nucleon-alpha and alpha-alpha interactions directly from the relevant binding energies and scattering phase shifts. The virial approach systematically takes into account contributions from bound nuclei and the resonant continuum, and consequently provides a framework to include strong-interaction corrections to nuclear statistical equilibrium models. The virial coefficients are used to make model-independent predictions for a variety of properties of nuclear matter over a range of densities, temperatures and compositions. Our results provide constraints on the physics of the neutrinosphere in supernovae. The resulting alpha particle concentration differs from all equations of state currently used in supernova simulations. Finally, the virial equation of state greatly improves our conceptual understanding of low-density nuclear matter.Comment: 15 pages, 17 figures, minor revisions, to appear in Nucl. Phys.

Topology of the ground state of two interacting Bose-Einstein condensates

We investigate the spatial patterns of the ground state of two interacting Bose-Einstein condensates. We consider the general case of two different atomic species (with different mass and in different hyperfine states) trapped in a magnetic potential whose eigenaxes can be tilted with respect to the vertical direction, giving rise to a non trivial gravitational sag. Despite the complicated geometry, we show that within the Thomas-Fermi approximations and upon appropriate coordinate transformations, the equations for the density distributions can be put in a very simple form. Starting from this expressions we give explicit rules to classify the different spatial topologies which can be produced, and we discuss how the behavior of the system is influenced by the inter-atomic scattering length. We also compare explicit examples with the full numeric Gross-Pitaevskii calculation.Comment: RevTex4, 8 pages, 7 figure

Fast evaluation of appointment schedules for outpatients in health care

We consider the problem of evaluating an appointment schedule for outpatients in a hospital. Given a fixed-length session during which a physician sees K patients, each patient has to be given an appointment time during this session in advance. When a patient arrives on its appointment, the consultations of the previous patients are either already finished or are still going on, which respectively means that the physician has been standing idle or that the patient has to wait, both of which are undesirable. Optimising a schedule according to performance criteria such as patient waiting times, physician idle times, session overtime, etc. usually requires a heuristic search method involving a huge number of repeated schedule evaluations. Hence, the aim of our evaluation approach is to obtain accurate predictions as fast as possible, i.e. at a very low computational cost. This is achieved by (1) using Lindley's recursion to allow for explicit expressions and (2) choosing a discrete-time (slotted) setting to make those expression easy to compute. We assume general, possibly distinct, distributions for the patient's consultation times, which allows us to account for multiple treatment types, as well as patient no-shows. The moments of waiting and idle times are obtained. For each slot, we also calculate the moments of waiting and idle time of an additional patient, should it be appointed to that slot. As we demonstrate, a graphical representation of these quantities can be used to assist a sequential scheduling strategy, as often used in practice

Boundary of two mixed Bose-Einstein condensates

The boundary of two mixed Bose-Einstein condensates interacting repulsively was considered in the case of spatial separation at zero temperature. Analytical expressions for density distribution of condensates were obtained by solving two coupled nonlinear Gross-Pitaevskii equations in cases corresponding weak and strong separation. These expressions allow to consider excitation spectrum of a particle confined in the vicinity of the boundary as well as surface waves associated with surface tension.Comment: 6 pages, 3 figures, submitted to Phys.Rev.