Proton Compton Scattering from Linearly Polarized Gamma Rays.

Differential cross sections for Compton scattering from the proton have been measured at scattering angles of 55°, 90°, and 125° in the laboratory frame using quasimonoenergetic linearly (circularly) polarized photon beams with a weighted mean energy value of 83.4 MeV (81.3 MeV). These measurements were performed at the High Intensity Gamma-Ray Source facility at the Triangle Universities Nuclear Laboratory. The results are compared to previous measurements and are interpreted in the chiral effective field theory framework to extract the electromagnetic dipole polarizabilities of the proton, which gives α_{E1}^{p}=13.8±1.2_{stat}±0.1_{BSR}±0.3_{theo},ß_{M1}^{p}=0.2∓1.2_{stat}±0.1_{BSR}∓0.3_{theo} in units of 10^{-4} fm^{3}.

Deeply Virtual Compton Scattering Cross Section at High Bjorken x_{B}.

We report high-precision measurements of the deeply virtual Compton scattering (DVCS) cross section at high values of the Bjorken variable x_{B}. DVCS is sensitive to the generalized parton distributions of the nucleon, which provide a three-dimensional description of its internal constituents. Using the exact analytic expression of the DVCS cross section for all possible polarization states of the initial and final electron and nucleon, and final state photon, we present the first experimental extraction of all four helicity-conserving Compton form factors (CFFs) of the nucleon as a function of x_{B}, while systematically including helicity flip amplitudes. In particular, the high accuracy of the present data demonstrates sensitivity to some very poorly known CFFs.

Form Factors and Two-Photon Exchange in High-Energy Elastic Electron-Proton Scattering.

We present new precision measurements of the elastic electron-proton scattering cross section for momentum transfer (Q^{2}) up to 15.75 (GeV/c)^{2}. Combined with existing data, these provide an improved extraction of the proton magnetic form factor at high Q^{2} and double the range over which a longitudinal or transverse separation of the cross section can be performed. The difference between our results and polarization data agrees with that observed at lower Q^{2} and attributed to hard two-photon exchange (TPE) effects, extending to 8 (GeV/c)^{2} the range of Q^{2} for which a discrepancy is established at >95% confidence. We use the discrepancy to quantify the size of TPE contributions needed to explain the cross section at high Q^{2}.

Deep Exclusive Electroproduction of π

We report measurements of the exclusive neutral pion electroproduction cross section off protons at large values of x_{B} (0.36, 0.48, and 0.60) and Q^{2} (3.1 to 8.4 GeV^{2}) obtained from Jefferson Lab Hall A experiment E12-06-014. The corresponding structure functions dσ_{T}/dt+εdσ_{L}/dt, dσ_{TT}/dt, dσ_{LT}/dt, and dσ_{LT^{'}}/dt are extracted as a function of the proton momentum transfer t-t_{min}. The results suggest the amplitude for transversely polarized virtual photons continues to dominate the cross section throughout this kinematic range. The data are well described by calculations based on transversity generalized parton distributions coupled to a helicity flip distribution amplitude of the pion, thus providing a unique way to probe the structure of the nucleon.

Mycobacterium tuberculosis lineages in Hawaii demonstrate distinctive demographic and migration characteristics.

OBJECTIVES: The American state of Hawaii presents a tuberculosis (TB) burden more consistent with that of the Philippines and the Pacific Islands than that with the United States (US) or Europe. This study seeks to determine if the genetic families of Mycobacterium tuberculosis (Mtb) that are prevalent in Hawaii display differences in host demographics that may be of use for TB control in Hawaii and the Pacific. STUDY DESIGN: This retrospective study was conducted by analyzing data from the Hawaii State Department of Health to investigate the demographics associated with the Beijing (global lineage 2) and Manila (lineage 1) families of Mtb in Hawaii. METHODS: Deidentified records of all culture-positive TB cases reported by the Hawaii State Department of Health Tuberculosis Control Program from 2004 to 2016 were analyzed to identify lineage-specific demographic differences and trends. Patients' countries of origin, age, sex, and time in the US before TB diagnosis were included in this analysis. RESULTS: Manila family isolates were found to predominantly enter Hawaii through Filipino immigrants, whereas Beijing family isolates originated from a diverse set of countries. Both families exhibited significant differences in age and sex demographics. In addition, Manila family cases presented from patients with significantly longer average time of residence in the US than non-Manila cases, whereas Beijing family cases presented from patients with significantly shorter time of residence in the US than non-Beijing cases. CONCLUSIONS: Both the Beijing and Manila families of Mtb demonstrated demographic differences in Hawaii that may prove important for improving TB control and surveillance policy in Hawaii and throughout the Pacific. Areas with heavy Filipino immigration may benefit from directing more resources toward screening and education efforts for middle-aged men and those who have resided in the country longer, whereas other areas of the Pacific should consider a younger and more sex-balanced allocation. Specific to the US and Hawaii, effective screening of youths emigrating from the Compact of Free Association states remains vital.

A screening model to predict microalgae biomass growth in photobioreactors and raceway ponds.

A microalgae biomass growth model was developed for screening novel strains for their potential to exhibit high biomass productivities under nutrient-replete conditions in photobioreactors or outdoor ponds. Growth is modeled by first estimating the light attenuation by biomass according to Beer-Lambert's Law, and then calculating the specific growth rate in discretized culture volume slices that receive declining light intensities due to attenuation. The model uses only two physical and two species-specific biological input parameters, all of which are relatively easy to determine: incident light intensity, culture depth, as well as the biomass light absorption coefficient and the specific growth rate as a function of light intensity. Roux bottle culture experiments were performed with Nannochloropsis salina at constant temperature (23°C) at six different incident light intensities (10, 25, 50, 100, 250, and 850 µmol/m(2) s) to determine both the specific growth rate under non-shading conditions and the biomass light absorption coefficient as a function of light intensity. The model was successful in predicting the biomass growth rate in these Roux bottle batch cultures during the light-limited linear phase at different incident light intensities. Model predictions were moderately sensitive to minor variations in the values of input parameters. The model was also successful in predicting the growth performance of Chlorella sp. cultured in LED-lighted 800 L raceway ponds operated in batch mode at constant temperature (30°C) and constant light intensity (1,650 µmol/m(2) s). Measurements of oxygen concentrations as a function of time demonstrated that following exposure to darkness, it takes at least 5 s for cells to initiate dark respiration. As a result, biomass loss due to dark respiration in the aphotic zone of a culture is unlikely to occur in highly mixed small-scale photobioreactors where cells move rapidly in and out of the light. By contrast, as supported also by the growth model, biomass loss due to dark respiration occurs in the dark zones of the relatively less well-mixed pond cultures. In addition to screening novel microalgae strains for high biomass productivities, the model can also be used for optimizing the pond design and operation. Additional research is needed to validate the biomass growth model for other microalgae species and for the more realistic case of fluctuating temperatures and light intensities observed in outdoor pond cultures.

Monitoring Skull Base Abnormalities in Children with Osteogenesis Imperfecta - Review of Current Practice and a Suggested Clinical Pathway.

OBJECTIVES: In the context of a lack of national consensus on the benefits of skull base imaging in children with osteogenesis imperfecta (OI), this study aims to analyse and correlate the clinical symptoms and radiological images of children with severe OI. METHODS: A retrospective case notes and image analysis was carried out on children with complex OI between 2012 and 2018 at a specialist tertiary centre. Data were collected on patient demographic factors, clinical data, imaging findings (presence of Wormian bones, platybasia, basilar impression (McGregor's technique) and basilar invagination (McRae's technique)), and clinical features at the time of imaging. RESULTS: Of the 127 patients in the OI database, 94 were included. A total of 321 radiographs, 21 CT scans and 39 MRI scans were analysed. Average frequency of radiographs was 8 per 10 years. Of the 94 patients, 58 (62%), 10 (11%), 1 (1%) demonstrated platybasia, basilar impression, and basilar invagination, respectively. Of the radiographs analysed, platybasia, basilar impression, basilar invagination, and the presence of Wormian bones, could not be evaluated in 71 (22.3%), 48 (15.2%), 61 (19.5%) and 28 (9.4%) radiographs respectively (due to poor positioning, anatomical abnormalities, and poor image quality). Of the 140 radiographs with platybasia, 17 (12%) also demonstrated basilar impression compared to only 3 (2.9%) out of the 99 without platybasia (p = 0.03). No significant associations were seen between the presence of Wormian bones and basilar impression. Of the 39 MRIs, additional information on CSF flow rate, spinal cord signal and cerebellar morphology was reported in 14 (36%). There was a lack of concordance between MRI and matched radiographs in 7.1% (1/14) and 36% (5/14) for platybasia and basilar impression respectively, with full concordance for basilar invagination. Fewer than 5% had positive clinical symptoms/signs at the time of imaging; 2% (7/321) had macrocephaly, 0.6% (2/321) headache, all other neurological features were absent). Clinical features were not documented in >85% of patients. CONCLUSION: The apparent low prevalence of clinical symptoms and signs and of radiologically identified cranio-cervical abnormalities, suggests that current levels of serial imaging may be excessive. Until larger prospective studies clarify these issues, we suggest a clinical pathway for base of skull imaging which proposes a risk stratification approach to radiographic frequency and suggests parameters for proceeding to MRI.

Purification and characterization of eight class 5 outer membrane protein variants from a clone of Neisseria meningitidis serogroup A.

Methods published for the purification of P.II proteins from Neisseria gonorrhoea have been modified to allow the purification of class 5 proteins from Neisseria meningitidis serogroup A bacteria. The five class 5 protein electrophoretic variants detected within an epidemic in the Gambia (a, b, c, d, and e) and three other variants (f, g, and h) found within other isolates of the same clone in West Africa have been purified with yields of 6-28 mg. The NH2-terminal amino acid sequence for variant c differs from those of the other class 5 proteins, whereas the latter are very similar to the sequence predicted for two class 5 proteins from DNA analyses of serogroup C meningococci and determined for 8 P.II proteins from gonococci. Numerous other regulatory, chemical, and serological differences were found between the c protein and the other class 5 proteins such that we recommend that the class 5 proteins be subdivided into two subclasses. mAbs have been isolated that distinguish between these two protein subclasses and Western blotting with these antibodies enabled us to conclude that both protein subclasses were found in bacteria isolated from different epidemics and pandemics of the last 50 yr.

Measurements of the electric form factor of the neutron up to Q2=3.4 GeV2 using the reaction 3He(e,e'n)pp.

The electric form factor of the neutron was determined from studies of the reaction 3He(e,e'n)pp in quasielastic kinematics in Hall A at Jefferson Lab. Longitudinally polarized electrons were scattered off a polarized target in which the nuclear polarization was oriented perpendicular to the momentum transfer. The scattered electrons were detected in a magnetic spectrometer in coincidence with neutrons that were registered in a large-solid-angle detector. More than doubling the Q2 range over which it is known, we find G(E)(n)=0.0236±0.0017(stat)±0.0026(syst), 0.0208±0.0024±0.0019, and 0.0147±0.0020±0.0014 for Q(2)=1.72, 2.48, and 3.41 GeV2, respectively.

Paleomagnetic record of a geomagnetic field reversal from late miocene mafic intrusions, southern nevada.

Late Miocene (about 8.65 million years ago) mafic intrusions and lava flows along with remagnetized host rocks from Paiute Ridge, southern Nevada, provide a high-quality paleomagnetic record of a geomagnetic field reversal. These rocks yield thermoremanent magnetizations with declinations of 227 degrees to 310 degrees and inclinations of -7 degrees to 49 degrees , defining a reasonably continuous virtual geomagnetic pole path over west-central Pacific longitudes. Conductive cooling estimates for the intrusions suggest that this field transition, and mafic magmatism, lasted only a few hundred years. Because this record comes principally from intrusive rocks, rather than sediments or lavas, it is important in demonstrating the longitudinal confinement of the geomagnetic field during a reversal.

Optimisation of the zinc sulphate turbidity test for the determination of immune status.

Failure of passive transfer of maternal immunity occurs in calves that fail to absorb sufficient immunoglobulins from ingested colostrum. The zinc sulphate turbidity test has been developed to test bovine neonates for this failure. The specificity of this test has been shown to be less than ideal. The objective was to examine how parameters of the zinc sulphate turbidity test may be manipulated in order to improve its diagnostic accuracy. One hundred and five blood samples were taken from calves of dairy cows receiving various rates of colostrum feeding. The zinc sulphate turbidity test was carried out multiple times on each sample, varying the solution strength, time of reaction and wavelength of light used and the results compared with those of a radial immunodiffusion test, which is the reference method for measuring immunoglobulin concentration in serum. Reducing the time over which the reaction occurs, or increasing the wavelength of light used to read the turbidity, resulted in decreased specificity without improving sensitivity. Increasing the concentration of the zinc sulphate solution used in the test was shown to improve the specificity without decreasing sensitivity. Examination of the cut-off points suggested that a lower cut-off point would improve the performance.

Preliminary trial of the effect of general practice based nutritional advice.

Despite formal recommendations for dietary change to reduce the incidence of ischaemic heart disease, the acceptability and effectiveness of the proposed diets have not been well investigated in population based studies. In this preliminary investigation of nutritional advice in a well population, subjects in one group practice were randomized to receive either dietary instruction or simple follow up without instruction. The dietary recommendations were well received, and a substantial proportion of subjects reported altering their diets in accordance with them. There were modest beneficial changes in plasma lipid levels among men. Thus, using general practice as an avenue for promoting dietary change is feasible, and may be effective among men.

The introduction and evaluation of magnetic resonance imaging in Australia.

The introduction of magnetic resonance imaging (MRI) into Australia was linked to a formal assessment of the technology in public hospitals associated with restrictions on government funding. The assessment produced comprehensive data on the usage, cost and efficacy of MRI in the hospital setting. This paper summarises the major results of the assessment and considers issues related to the methodology used and the impact on the policy process.

A review of the experience with teleradiology in Australia.

Because of the geographical dispersion of the Australian population (25-30% of the total population of 20 million live outside metropolitan areas), there has been considerable interest in the use of teleradiology. In general, the provision of teleradiology by private radiology practices has been successful. However, as regards the provision of publicly funded, statewide teleradiology services, progress has been slower than expected, following enthusiastic support for the technology in the early 1990s. While there have been some notable successes in the implementation of publicly funded teleradiology services, given the delays that have been experienced in Australia, there is a case for a closer connection between the conduct of teleradiology evaluation studies and the incorporation of the results into health policy. This link would ensure that the benefits of technology are made available to the public in as short a time as possible.

Cost-effectiveness analysis of telemedicine.

There are a number of different costs associated with the development and operation of telemedicine services. A model is proposed in order to assist in strengthening the evidence base for telemedicine. It includes the following components: project establishment costs; equipment costs; maintenance costs; communication costs; staffing costs. All need to be considered in arriving at an annual cost figure for operating a telemedicine service. The inclusion of all these costs, prepared in the standard manner outlined in the model, will ensure that a realistic cost figure is available when evaluating the cost-effectiveness of a telemedicine service.

Telemedicine in Australia. Recent developments.

There have been a number of important developments in Australia in the area of telemedicine. At the national level, the House of Representatives' Standing Committee on Family and Community Affairs has been conducting the Inquiry into Health Information Management and Telemedicine. The Australian Health Ministers' Advisory Council has supported the establishment of a working party convened by the South Australian Health Commission to prepare a detailed report on issues relating to telemedicine. State governments have begun a number of telemedicine projects, including major initiatives in New South Wales and Victoria and the extensive development of telepsychiatry services in Queensland. Research activities in high-speed image transmission have been undertaken by the Australian Computing and Communications Institute and Telstra, and by the Australian Navy. The matter of the funding of both capital and recurrent costs of telemedicine services has not been resolved, and issues of security and privacy of medical information are subjects to discussion. The use of the Internet as a universal communications medium may provide opportunities for the expansion of telemedicine services, particularly in the area of continuing medical education. A need has been recognized for the coordinated evaluation of telemedicine services as cost-benefit considerations are seen to be very important.

Teleradiology at a children's hospital: a pilot study.

A pilot teleradiology project was conducted between the Royal Alexandra Hospital for Children in Camperdown, central Sydney, and Nepean Hospital in Penrith, about 48 km away. Over three months 575 paediatric radiographs were transmitted at full resolution. The results demonstrated that it was possible to transmit paediatric chest images of diagnostic quality in a reliable and secure manner. Mean transmission time per image was 3.26 min using ISDN, which was considered to be acceptable. Costs were calculated in terms of transmission, equipment, maintenance and staff components. The cost per image transmitted would vary from A$80 for 2500 images per year to A$34 for 10,000 images per year. The experience of the pilot study suggested that more widespread introduction of high-quality paediatric telemedicine in Australia would be feasible. Adoption of the technique would have major implications for paediatric health care, including potential improvements in patient management due to quicker diagnosis and earlier intervention, and potential savings through avoiding transfer of some emergency cases.

CT and MRI scanning. Specialised imaging techniques.

Advanced diagnostic imaging methods, while offering many benefits to patients, have caused concern because of the additive nature of the technologies and their costs. The authors outline the indications for the use of computed tomography and magnetic resonance imaging, discuss costs, availability and major indications for use, and recommend increased use of imaging algorithms in the selection of diagnostic tests.