Recent Ionospheric Observations Relating to Solar-Wind--Magnetosphere Coupling [and Discussion]

Simultaneous observations in the high-latitude ionosphere and in the near-Earth interplanetary medium have revealed the control exerted by the interplanetary magnetic field and the solar wind flow on field-perpendicular convection of plasma in both the ionosphere and the magnetosphere. Previous studies, using statistical surveys of data from both low-altitude polar-orbiting satellites and ground-based radars and magnetometers, have established that magnetic reconnection at the dayside magnetopause is the dominant driving mechanism for convection. More recently, ground-based data and global auroral images of higher temporal resolution have been obtained and used to study the response of the ionospheric flows to changes in the interplanetary medium. These observations show that ionospheric convection responds rapidly (within a few minutes) to both increases and decreases in the reconnection rate over a range of spatial scales, as well as revealing transient enhancements which are also thought to be related to magnetopause phenomena. Such results emphasize the potential of ground-based radars and other remote-sensing instruments for studies of the Earth's interaction with the interplanetary medium.

Eastward propagation of a plasma convection enhancement following a southward turning of the interplanetary magnetic field

On October 27th 1984, high-latitude ionospheric convection was observed by the European incoherent scatter (EISCAT) radar. For a nine-hour period, simultaneous observations of the interplanetary magnetic field (IMF) were obtained sunward of the Earth's bow shock. During this period, the IMF abruptly turned southward, having previously been predominantly northward for approximately three hours, and a strong enhancement in convection was observed 11 ± 1 minutes later. Using the very high time resolution of the EISCAT data, it is shown that the convection enhancement propagated eastward, around the afternoon magnetic local time sector, at a speed of the order of 1 kms−1. These results are interpreted in terms of the effects of an onset of steady IMF-geomagnetic field merging and are the first to show how a new pattern of enhanced convection is established in the high latitude ionosphere.

The umbilical cord in Cantrell: Pentalogy or Hexalogy?

Objective: Pentalogy of Cantrell (PC) is a rare congenital defect associated with five midline anomalies. The type of cardiac malformation and the size of the abdominal wall defect is often responsible for the high mortality. Of interest, the embryonic period in which PC develops is similar to that of the umbilical cord’s (UC) formation. The aim of the following study was to investigate the relationship between UC anomalies and PC. Methods: Charts of four cases with PC from 2002–08 were retrospectively reviewed for associated UC anomalies. UC anomalies were defined as single umbilical artery (SUA), short cord (during 1st trimester less than CRL or less than 30cm at term) or atypical UC coiling pattern. Results: We identified four cases: 3 singletons and one monochorionic diamniotic twin pregnancy with TRAP sequence. All cases showed a normal karyotype. All but one demonstrated the classical pulsatile omphalocele with ectopia cordis and all others anomalies of PC. One case was characterized by a major cranial omphalocele without ectopia cordis and no UC anomaly. This fetus was delivered by Cesarean at term and successfully operated on d1. In all other cases the parents requested ToP. Among the three cases with ectopia cordis, two had a short UC with SUA and one a short three-vessel cord; all these three UC were markedly uncoiled. Conclusions: Our data suggest a strong association between Cantrell and the development of the UC, in particular in cases with ectopia cordis. One might speculate that hemodynamic alterations of the feto-placental blood flow because of the cardiac malformation or structural changes at the umbilical ring (omphalocele) influence the development of the UC. More observations are needed to decide if Cantrell is a ‘‘hexalogy’’ instead of pentalogy.

An application of the Health Belief Model to understanding use of child restraint practices

Aims Multi-method study including two parts: Study One: three sets of observations in two regional areas of Queensland Study Two: two sets of parent intercept interviews conducted in Toowoomba, Queensland. The aim of Study Two is to determine parents’ views, opinions and knowledge of child restraint practices and the Queensland legislative amendment.

Understanding the impact of legislative changes on child car seating and restraint practices in regional Queensland

Road crashes contribute to a significant amount of child mortality and morbidity in Australia. In fact, passenger injuries contribute to the majority of child crash road trauma. A number of factors contribute to child injury and death in motor vehicles, including inappropriate seating position, inappropriate choice of restraint, and incorrect installation and use of child restraints. Prior to March 2010, child restraint legislation in Queensland only required children twelve months and younger to be seated in a properly adjusted and fastened child restraint. This legislation left older infants and young children potentially suboptimally protected. From March 2010, new legislation specified seating position and type of child restraint required, depending on the age of the child. This research was underpinned by the Health Belief Model (HBM), which explores health related behaviour, behaviour change, environmental factors influencing behaviour change (including legislative changes) and is flexible enough to be used in relation to parents' health practices for their children, rather than parent health directly. This thesis investigates the extent to which the changes to child restraint legislation have led parents in regional areas of Queensland to use appropriate restraint practices for their children and determines the extent to which the constructs of the HBM, parental perceptions, barriers and environmental factors contribute to the appropriateness of child seating and restraint use. Study One included three sets of observations taken in two regional cities of Queensland prior to the legislative amendment, during an educative period of six months, and after the enactment of the legislation. Each child's seating position and restraint type were recorded. Results showed that the proportion of children observed occupying the front seat decreased by 15.6 per cent with the announcement the legislation. There was no decrease in front seat use at the enactment of the legislation. The proportion of children observed using dedicated child restraints increased by 8.8 per cent with the announcement of the legislation when there was one child in the vehicle. Further, there was a 10.1 per cent increase in the proportion of children observed using a seat belt that fit with the announcement when there was one child in the vehicle and with the enactment of the legislation regardless of the number of children in the vehicle (21.8 per cent for one child, 39.7 per cent for two children and 40.2 per cent for three or more children). Study Two comprised initial intercept interviews, later followed up by telephone, with parents with children aged eight years and younger at the announcement and telephone interviews at the enactment of the legislation in one regional city in Queensland. Parents reported their child restraint practices, and opinions, knowledge and understanding of the requirements of the new legislation. Parent responses were analysed in terms of the constructs in the HBM. When asked which seating position their child 'usually' used, parents reported child front seat use was nil (0.0 per cent) and did not change with the enactment of the legislative amendment. However, when parents were asked whether they allowed children to use the front seat at some point within the six months prior to the interview, reported child front seat use was 7 (5.4 per cent) children at T2 and 10 (9.6 per cent) at T3. Reported use of age-appropriate child restraints did not increase with the enactment of the legislation (p = 0.77, ns). Parents reported restraint practices were classed as either appropriate or inappropriate. Parents who reported appropriate restraint practices were those whose children were sitting in optimal restraints and seating positions for their age according to the requirements of the legislation. Parents who reported inappropriate restraint practices were those who had one or more children who were suboptimally restrained or seated for their age according to the requirements of the legislation. Neither parents' perceptions about their susceptibility of being in a crash nor the likelihood of severity of child injury if involved in a crash yielded significant differences in the appropriateness of reported parent restraint practices over time with the enactment of the legislation. A trend in the data suggested parents perceived a benefit to using appropriate restraint practices was to avoid fines and demerit points. Over 75 per cent of parents who agreed that child restraints provide better protection for children than an adult seat belt reported appropriately seating and restraining their children (2 (1) = 8.093, p<.05). The self-efficacy measure regarding parents' confidence in installing a child restraint showed a significant association with appropriate parental restraint practices (2 (1) = 7.036, p<.05). Results suggested that some parents may have misinterpreted the announcement of the legislative amendment as the announcement of the enforcement of the legislation instead. Some parents who correctly reported details of the legislation did not report appropriate child restraint practices. This finding shows that parents' knowledge of the legislative amendment does not necessarily have an impact on their behaviour to appropriately seat and restrain children. The results of these studies have important implications for road safety and the prevention of road-related injury and death to children in Queensland. Firstly, parents reported feeling unsure of how to install restraints, which suggests that there may be children travelling in restraints that have not been installed correctly, putting them at risk. Interventions to alert and encourage parents to seek advice when unsure about the correct installation of child restraints could be considered. Secondly, some parents in this study although they were using the most appropriate restraint for their children, reported using a type that was not the most appropriate restraint for the child's age according to the legislation. This suggests that intervention may be effective in helping parents make a more accurate choice of the most appropriate type of restraint to use with children, especially as the child ages and child restraint requirements change. Further research could be conducted to ascertain the most effective methods of informing and motivating parents to use the most appropriate restraints and seating positions for their children, as these results show a concerning disparity between reported restraint practices and those that were observed.

The navigation and visualisation of environmental audio using zooming spectrograms

Acoustic recordings play an increasingly important role in monitoring terrestrial and aquatic environments. However, rapid advances in technology make it possible to accumulate thousands of hours of recordings, more than ecologists can ever listen to. Our approach to this big-data challenge is to visualize the content of long-duration audio recordings on multiple scales, from minutes, hours, days to years. The visualization should facilitate navigation and yield ecologically meaningful information prior to listening to the audio. To construct images, we calculate acoustic indices, statistics that describe the distribution of acoustic energy and reflect content of ecological interest. We combine various indices to produce false-color spectrogram images that reveal acoustic content and facilitate navigation. The technical challenge we investigate in this work is how to navigate recordings that are days or even months in duration. We introduce a method of zooming through multiple temporal scales, analogous to Google Maps. However, the “landscape” to be navigated is not geographical and not therefore intrinsically visual, but rather a graphical representation of the underlying audio. We describe solutions to navigating spectrograms that range over three orders of magnitude of temporal scale. We make three sets of observations: 1. We determine that at least ten intermediate scale steps are required to zoom over three orders of magnitude of temporal scale; 2. We determine that three different visual representations are required to cover the range of temporal scales; 3. We present a solution to the problem of maintaining visual continuity when stepping between different visual representations. Finally, we demonstrate the utility of the approach with four case studies.

Turbulent free convection above a heated plate inclined at a small angle to the horizontal Journal

An investigation has been made of the structure of the motion above a heated plate inclined at a small angle (about 10°) to the horizontal. The turbulence is considered in terms of the similarities to and differences from the motion above an exactly horizontal surface. One effect of inclination is, of course, that there is also a mean motion. Accurate data on the mean temperature field and the intensity of the temperature fluctuations have been obtained with platinum resistance thermometers, the signals being processed electronically. More approximate information on the velocity field has been obtained with quartz fibre anemometers. These results have been supplemented qualitatively by simultaneous observations of the temperature and velocity fluctuations and also by smoke experiments. The principal features of the flow inferred from these observations are as follows. The heat transfer and the mean temperature field are not much altered by the inclination, though small, not very systematic, variations may result from the complexities of the velocity field. This supports the view that the mean temperature field is largely governed by the large-scale motions. The temperature fluctuations show a systematic variation with distance from the lower edge and resemble those above a horizontal plate when this distance is large. The largescale motions of the turbulence start close to the lower edge, but the smaller eddies do not attain full intensity until the air has moved some distance up the plate. The mean velocity receives a sizable contribution from a ‘through-flow’ between the side-walls. Superimposed on this are developments that show that the momentum transfer processes are complex and certainly not capable of representation by any simple theory such as an eddy viscosity. On the lower part of the plate there is surprisingly large acceleration, but further up the mixing action of the small eddies has a decelerating effect.

Si nanowire growth on sapphire: Classical incubation, reverse reaction, and steady state supersaturation

Si nanowire growth on sapphire substrates by the vapor-liquid-solid (VLS) method using Au catalyst particles has been studied. Sapphire was chosen as the substrate to ensure that the vapor phase is the only source of Si. Three hitherto unreported observations are described. First, an incubation period of 120-480 s, which is shown to be the incubation period as defined in classical nucleation theory, is reported. This incubation period permits the determination of a desolvation energy of Si from Au-Si alloys of 15 kT. Two, transmission electron microscopy studies of incubation, point to Si loss by reverse reaction as an important part of the mechanism of Si nanowire growth by VLS. Three, calculations using these physico-chemical parameters determined from incubation and measured steady state growth rates of Si nanowires show that wire growth happens from a supersaturated catalyst droplet. (C) 2015 AIP Publishing LLC.

Testing inflationary cosmology with the BICEP1 and BICEP2 experiments

Recent observations of the temperature anisotropies of the cosmic microwave background (CMB) favor an inflationary paradigm in which the scale factor of the universe inflated by many orders of magnitude at some very early time. Such a scenario would produce the observed large-scale isotropy and homogeneity of the universe, as well as the scale-invariant perturbations responsible for the observed (10 parts per million) anisotropies in the CMB. An inflationary epoch is also theorized to produce a background of gravitational waves (or tensor perturbations), the effects of which can be observed in the polarization of the CMB. The E-mode (or parity even) polarization of the CMB, which is produced by scalar perturbations, has now been measured with high significance. Con- trastingly, today the B-mode (or parity odd) polarization, which is sourced by tensor perturbations, has yet to be observed. A detection of the B-mode polarization of the CMB would provide strong evidence for an inflationary epoch early in the universe’s history.

In this work, we explore experimental techniques and analysis methods used to probe the B- mode polarization of the CMB. These experimental techniques have been used to build the Bicep2 telescope, which was deployed to the South Pole in 2009. After three years of observations, Bicep2 has acquired one of the deepest observations of the degree-scale polarization of the CMB to date. Similarly, this work describes analysis methods developed for the Bicep1 three-year data analysis, which includes the full data set acquired by Bicep1. This analysis has produced the tightest constraint on the B-mode polarization of the CMB to date, corresponding to a tensor-to-scalar ratio estimate of r = 0.04±0.32, or a Bayesian 95% credible interval of r < 0.70. These analysis methods, in addition to producing this new constraint, are directly applicable to future analyses of Bicep2 data. Taken together, the experimental techniques and analysis methods described herein promise to open a new observational window into the inflationary epoch and the initial conditions of our universe.

Upconversion luminescence of Ce3+ doped BK7 glass by femtosecond laser irradiation

Near-infrared to visible upconversion luminescence was observed in a multicomponent silicate (BK7) glass containing Ce3+ ions under focused infrared femtosecond laser irradiation. The emission spectra show that the upconversion luminescence comes from the 4f-5d transition of the Ce3+ ions. The relationship between the intensity of the Ce3+ emission and the pump power reveals that a three-photon absorption predominates in the conversion process from the near-infrared into the blue luminescence. The analysis of the upconversion mechanism suggests that the upconversion luminescence may come from a three-photon simultaneous absorption that leads to a population of the 5d level in which the characteristic luminescence occurs.

Blue upconversion luminescence generation in Ce3+: Gd2SiO5 crystals by infrared femtosecond laser irradiation

Blue frequency-upconversion fluorescence emission has been observed in Ce3+-doped Gd2SiO5 single crystals, pumped with 120-fs 800 nm IR laser pulses. The observed fluorescence emission peaks at about 440nm is due to 5d -> 4f transition of Ce3+ ions. The intensity dependence of the blue fluorescence emission on the IR excitation laser power obeys the cubic law, demonstrating three-photon absorption process. Analysis suggested that three-photon simultaneous absorption induced population inversion should be the predominant frequency upconversion mechanism. (c) 2006 Optical Society of America.

Investigation of two-proton emission from excited states of the odd-Z nucleus P-28 by complete-kinematics measurements

An experiment to study exotic two-proton emission from excited levels of the odd-Z nucleus P-28 was performed at the National Laboratory of Heavy Ion Research-Radioactive Ion Beam Line (HIRFL-RIBLL) facility. The projectile P-28 at the energy of 46.5 MeV/u was bombarding a Au-197 target to populate the excited states via Coulomb excitation. Complete-kinematics measurements were realized by the array of silicon strip detectors and the CsI + PIN telescope. Two-proton events were selected and the relativistic-kinematics reconstruction was carried out. The spectrum of relative momentum and opening angle between two protons was deduced from Monte Carlo simulations. Experimental results show that two-proton emission from P-28 excited states less than 17.0 MeV is mainly two-body sequential emission or three-body simultaneous decay in phase space. The present simulations cannot distinguish these two decay modes. No obvious diproton emission was found.

Early-type stars observed in the ESO UVES Paranal Observatory Project - III. Sub-parsec and AU-scale structure in the interstellar medium

UVES interstellar observations from the Paranal Observatory Project are presented for early-type stars located in the line of sight to the nearby open clusters IC 2391 (Omni Vel) and NGC 6475 (M7), with spectroscopic resolution R similar to 80 000 and signal-to-noise ratios in the Ti II (3383 angstrom), Ca II K, CH+ (4232 angstrom), Na I D and K I (7698 angstrom) lines of several hundred. The sightlines are a mixture of cluster and non-cluster objects. A total of 22 early-type stars (A and B type) are present in our sample towards IC 2391, with 21 towards NGC 6475/M7, and enable us to probe for differences in column density on scales from similar to 0.07 to 7.3 and similar to 0.05 to 4.9 pc in the respective clusters. Additionally, towards Praesepe the Na I D interstellar variation only is probed towards 13 sightlines and transverse scales of similar to 0.16-10.7 pc at R = 70 000. Towards IC 2391 variations are found in Ti II, Ca II K and Na I D column density in different sightlines of up to 0.7, 1.0 and 1.8 dex (excluding one star), respectively. This kind of variability correlates well with the Hipparcos parallax of the objects, and probes structure within the Local Bubble. For cluster-only objects the variations are 0.3, 0.3 and 0.5 dex, respectively. For the field of view towards NGC6475 the corresponding maximum variations are somewhat smaller, being 0.5, 0.3, 0.8 and 1.0 dex for Ti II, Ca II K, Na I and K I, respectively, for all objects and 0.4, 0.2, 0.6 and 0.7 dex for the cluster-only objects. These are uncorrelated with parallax, and again demonstrate that Ca II K tends to be more smoothly distributed than Na I D. A few likely cluster sightlines show evidence for CH+ and variations in this molecular species of a factor of 10 in equivalent width over sub-pc scales. Towards Praesepe variation in interstellar Na I D is small, being a maximum of only similar to 0.4 dex (including measurement errors), but with fewer sightlines studied. Overall, the scatter in the data is similar for the singly ionized species Ti II and Ca II, lending more support to the hypothesis that these two species sample similar parts of the interstellar medium (ISM). This also appears to be the case for the neutral species Na I D and K I in the one cluster studied. Finally, multiple-epoch observations from a variety of archive sources are used to search for astronomical unit (au) scale structure in the ISM towards 46 sightlines. There are tentative indications of structure on scales of tens to thousands of au for three sightlines. Future observations will confirm the veracity or otherwise of the time-variable components and others presented.

Coupled Effects of a Perturbation in a Complex Structure Observed with SDO/AIA, SDO/HMI and ROSA/HARDcam

We study properties of intensity fluctuations in NOAA Active Region 11250 observed on 13 July 2011 starting at UT 13:32. Included are data obtained in the EUV bands of the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory (SDO/AIA) as well as nearly simultaneous observations of the chromosphere made, at much higher spatial and temporal resolution, with the Rapid Oscillations in the Solar Atmosphere (ROSA) and Hydrogen-Alpha Rapid Dynamics camera (HARDcam) systems at the Dunn Solar Telescope. A complex structure seen in both the ROSA/HARDcam and SDO data sets comprises a system of loops extending outward from near the boundary of the leading sunspot umbra. It is visible in the ROSA Ca II K and HARDcam Hα images, as well as the SDO 304 Å, 171 Å and 193 Å channels, and it thus couples the chromosphere, transition region and corona. In the ground-based images the loop structure is 4.1 Mm long. Some 17.5 Mm, can be traced in the SDO/AIA data. The chromospheric emissions observed by ROSA and HARDcam appear to occupy the inner, and apparently cooler and lower, quarter of the loop. We compare the intensity fluctuations of two points within the structure. From alignment with SDO/HMI images we identify a point "A" near the loop structure, which sits directly above a bipolar magnetic feature in the photosphere. Point "B" is characteristic of locations within the loops that are visible in both the ROSA/HARDcam and the SDO/AIA data. The intensity traces for point A are quiet during the first part of the data string. At time ~ 19 min they suddenly begin a series of impulsive brightenings. In the 171 Å and 193 Å coronal lines the brightenings are localized impulses in time, but in the transition region line at 304 Å they are more extended in time. The intensity traces in the 304 Å line for point B shows a quasi-periodic signal that changes properties at about 19 min. The wavelet power spectra are characterized by two periodicities. A 6.7 min period extends from the beginning of the series until about 25 minutes, and another signal with period ~3 min starts at about 20 min. The 193 Å power spectrum has a characteristic period of 5 min, before the 20 min transition and a 2.5 min periodicity afterward. In the case of HARDcam Hα data a localized 4 min periodicity can be found until about 7 min, followed by a quiet regime. After ~20 min a 2.3 min periodicity appears. Interestingly a coronal loop visible in the 94 Å line that is centrally located in the AR, running from the leading umbra to the following polarity, at about time 20 min undergoes a strong brightening beginning at the same moment all along 15 Mm of its length. The fact that these different signals all experience a clear-cut change at time about 20 min suggests an underlying organizing mechanism. Given that point A has a direct connection to the photospheric magnetic bipole, we conjecture that the whole extended structure is connected in a complex manner to the underlying magnetic field. The periodicities in these features may favor the wave nature rather than upflows and interpretations will be discussed.

Rapid Oscillations in the Solar Atmosphere: Spectra and Physical Effects

High-frequency fluctuations are observed with the Rapid Oscillations in the Solar Atmosphere (ROSA) instrument (Jess et al. 2010, Solar Phys, 261, 363) at the Dunn Solar Telescope. This can produce simultaneous observations in up to six channels, at different heights in the photosphere and chromosphere, at an unprecedentedly high cadence of 0.5 seconds, and at a spatial resolution of 100 km after photometrically correct speckle reconstruction. Here we concentrate on observations at two levels. The first is in the G-band of the CH radical at 4305.5Å, bandpass 9.2Å, with height of formation z <250 km at a cadence of 0.525 sec corresponding to Nyquist frequency 950 mHz. The second is in the Ca II K-line core at 3933.7Å, bandpass 1.0Å, with height of formation z <1300 km, and cadence 4.2 sec giving Nyquist frequency 120 mHz. The data span 53 min, and the maximum field of view is 45 Mm. The data were taken on 28 May 2009 in internetwork and network near disk center. Using both Fourier and Morlet wavelet methods we find evidence in the G-band spectra for intensity fluctuations above noise out to frequencies f >> 100 mHz. The K-line signal is noisier and is seen only for f <50 mHz. With wavelet techniques we find that G-band spectral power with 20 <f <100 mHz is clearly concentrated in the intergranular lanes and especially at the locations of magnetic elements indicated by G-band bright points. This wavelet power is highly intermittent in time. By cross-correlating the data we find that pulses of high-frequency G-band power in the photosphere tend to be followed by increases in K-line emission in the chromosphere with a time lag of about 2 min.