Type 2 radio bursts, interplanetary shocks and energetic particle events

Using the ISEE-3 radio astronomy experiment data 37 interplanetary (IP) type II bursts have been identified in the period September 1978 to December 1981. These events and the associated phenomena are listed. The events are preceded by intense, soft X ray events with long decay times (LDEs) and type II and/or type IV bursts at meter wavelengths. The meter wavelength type II bursts are usually intense and exhibit herringbone structure. The extension of the herringbone structure into the kilometer wavelength range results in the occurrence of a shock accelerated (SA) event. The majority of the interplanetary type II bursts are associated with energetic particle events. These results support other studies which indicate that energetic solar particles detected at 1 A.U. are generated by shock acceleration. From a preliminary analysis of the available data there appears to be a high correlation with white light coronal transients

Two classes of solar energetic particle events associated with impulsive and long duration soft X-ray flares

Solar energetic particle events observed in space have different properties depending on the class of associated flare. Impulsive flares, which occur low in the corona in regions of high energy density, are associated with particle events which are deficient in protons. These events are rarely associated with coronal mass ejections and interplanetary shocks. The vast majority of large, high energy proton events are associated with long duration flares, many of which are also associated with fast coronal mass ejections and strong interplanetary shocks. Such flare events originate relatively high in the corona

Type 2 solar radio events observed in the interplanetary medium. Part 1: General characteristics

Twelve type 2 solar radio events were observed in the 2 MHz to 30 kHz frequency range by the radio astronomy experiment on the ISEE-3 satellite over the period from September 1978 to December 1979. These data provide the most comprehensive sample of type 2 radio bursts observed at kilometer wavelengths. Dynamic spectra of a number of events are presented. Where possible, the 12 events were associated with an initiating flare, ground based radio data, the passage of a shock at the spacecraft, and the sudden commencement of a geomagnetic storm. The general characteristics of kilometric type 2 bursts are discussed

Fast drift kilometric radio bursts and solar proton events

Initial results of a comparative study of major fast drift kilometric bursts and solar proton events from Sep. 1978 to Feb. 1983 are presented. It was found that only about half of all intense, long duration ( 40 min above 500 sfu) 1 MHz bursts can be associated with F 20 MeV proton events. However, for the subset of such fast drift bursts accompanied by metric Type 2 and/or 4 activity (approximately 40% of the total), the degree of association with 20 MeV events is 80%. For the reverse association, it was found that proton events with J( 20 MeV) 0.01 1 pr cm(-2)s(-1)sr(-1)MeV(-1) were typically (approximately 80% of the time) preceded by intense 1 MHz bursts that exceeded the 500 sfu level for times 20 min (median duration approximately 35 min)

Role of Flares and Shocks in Determining Solar Energetic Particle Abundances

We examine solar energetic particle (SEP) event-averaged abundances of Fe relative to O and intensity versus time profiles at energies above 25 MeV/nucleon using the SIS instrument on ACE. These data are compared with solar wind conditions during each event and with estimates of the strength of the associated shock based on average travel times to 1 AU. We find that the majority of events with an Fe to O abundance ratio greater than two times the average 5–12 MeV/nuc value for large SEP events (0.134) occur in the western hemisphere. Furthermore, in most of these Fe-rich events the profiles peak within 12 hours of the associated flare, suggesting that some of the observed interplanetary particles are accelerated in these flares. The vast majority of events with Fe/O below 0.134 are influenced by interplanetary shock acceleration. We suggest that variations in elemental composition in SEP events mainly arise from the combination of flare particles and shock acceleration of these particles and/or the ambient medium

The Roles of Flares and Shocks in determining SEP Abundances

We examine solar energetic particle (SEP) event-averaged abundances of Fe relative to O and intensity versus time profiles at energies above 25 MeV/nucleon using the SIS instrument on ACE. These data are compared with solar wind conditions during each event and with estimates of the strength of the associated shock based on average travel times to 1 AU. We find that the majority of events with an Fe to 0 abundance ratio greater than two times the average 5-12 MeV/nuc value for large SEP events (0.134) occur in the western hemisphere. Furthermore, in most of these Fe-rich events the profiles peak within 12 hours of the associated flare, suggesting that some of the observed interplanetary particles are accelerated in these flares. The vast majority of events with Fe/O below 0.134 are influenced by interplanetary shock acceleration. We suggest that variations in elemental composition in SEP events mainly arise from the combination of flare particles and shock acceleration of these particles and/or the ambient medium

Relativistic Proton Production During the 14 July 2000 Solar Event: The Case for Multiple Source Mechanisms

Protons accelerated to relativistic energies by transient solar and interplanetary phenomena caused a ground-level cosmic ray enhancement on 14 July 2000, Bastille Day. Near-Earth spacecraft measured the proton flux directly and ground-based observatories measured the secondary responses to higher energy protons. We have modelled the arrival of these relativistic protons at Earth using a technique which deduces the spectrum, arrival direction and anisotropy of the high-energy protons that produce increased responses in neutron monitors. To investigate the acceleration processes involved we have employed theoretical shock and stochastic acceleration spectral forms in our fits to spacecraft and neutron monitor data. During the rising phase of the event (10:45 UT and 10:50 UT) we find that the spectrum between 140 MeV and 4 GeV is best fitted by a shock acceleration spectrum. In contrast, the spectrum at the peak (10:55 UT and 11:00 UT) and in the declining phase (11:40 UT) is best fitted with a stochastic acceleration spectrum. We propose that at least two acceleration processes were responsible for the production of relativistic protons during the Bastille Day solar event: (1) protons were accelerated to relativistic energies by a shock, presumably a coronal mass ejection (CME). (2) protons were also accelerated to relativistic energies by stochastic processes initiated by magnetohydrodynamic (MHD) turbulence.Comment: 38 pages, 9 figures, accepted for publication in the Astrophysical Journal, January, 200

Desarrollo de una vacuna inactivada contra la epidermitis exudativa porcina utilizando dos adyuvantes

Staphylococcus hyicus es el agente responsable de provocar la Epidermitis exudativa, una afección de la piel que afecta a los lechones lactantes y destetados menores de 6 semanas de edad. Esta patología se caracteriza por generar lesiones con exudación grasa, descamación y la formación de vesículas. A nivel global presenta una alta incidencia, con una variabilidad en la morbilidad del 20% al 100%, mientras que la mortalidad oscila entre el 50% y el 75%. En Argentina no se dispone actualmente de una vacuna que prevenga esta enfermedad, a pesar de que la inmunización se ha mostrado como una estrategia efectiva en la prevención de los procesos infecciosos en animales. Por lo tanto, el objetivo central de este estudio fue desarrollar dos bacterinas autógenas dirigidas contra Staphylococcus hyicus. Una de estas bacterinas se formuló utilizando un adyuvante convencional (hidróxido de aluminio), mientras que la otra utilizó el adyuvante inmunoestimulante (ISPA). La vacuna se empleó para inmunizar a cerdas preñadas, que fueron agrupadas según el adyuvante utilizado en la inmunización. La evaluación clínica se centró en determinar la tolerancia de las cerdas a las bacterinas. El resultado de esta evaluación fue exitoso, lo que marca un paso importante en la investigación y el desarrollo de medidas preventivas ante la Epidermitis exudativa

An Extreme Solar Event of 20 January 2005: Properties of the Flare and the Origin of Energetic Particles

The extreme solar and SEP event of 20 January 2005 is analyzed from two perspectives. Firstly, we study features of the main phase of the flare, when the strongest emissions from microwaves up to 200 MeV gamma-rays were observed. Secondly, we relate our results to a long-standing controversy on the origin of SEPs arriving at Earth, i.e., acceleration in flares, or shocks ahead of CMEs. All emissions from microwaves up to 2.22 MeV line gamma-rays during the main flare phase originated within a compact structure located just above sunspot umbrae. A huge radio burst with a frequency maximum at 30 GHz was observed, indicating the presence of a large number of energetic electrons in strong magnetic fields. Thus, protons and electrons responsible for flare emissions during its main phase were accelerated within the magnetic field of the active region. The leading, impulsive parts of the GLE, and highest-energy gamma-rays identified with pi^0-decay emission, are similar and correspond in time. The origin of the pi^0-decay gamma-rays is argued to be the same as that of lower energy emissions. We estimate the sky-plane speed of the CME to be 2000-2600 km/s, i.e., high, but of the same order as preceding non-GLE-related CMEs from the same active region. Hence, the flare itself rather than the CME appears to determine the extreme nature of this event. We conclude that the acceleration, at least, to sub-relativistic energies, of electrons and protons, responsible for both the flare emissions and the leading spike of SEP/GLE by 07 UT, are likely to have occurred simultaneously within the flare region. We do not rule out a probable contribution from particles accelerated in the CME-driven shock for the leading GLE spike, which seemed to dominate later on.Comment: 34 pages, 14 Postscript figures. Solar Physics, accepted. A typo corrected. The original publication is available at http://www.springerlink.co

Understanding childhood asthma in focus groups: perspectives from mothers of different ethnic backgrounds

BACKGROUND: Diagnosing childhood asthma is dependent upon parental symptom reporting but there are problems in the use of words and terms. The purpose of this study was to describe and compare understandings of childhood 'asthma' by mothers from three different ethnic backgrounds who have no personal experience of diagnosing asthma. A better understanding of parents' perceptions of an illness by clinicians should improve communication and management of the illness. METHOD: Sixty-six mothers living in east London describing their ethnic backgrounds as Bangladeshi, white English and black Caribbean were recruited to 9 focus groups. Discussion was semi-structured. Three sessions were conducted with each ethnic group. Mothers were shown a video clip of a boy with audible wheeze and cough and then addressed 6 questions. Sessions were recorded and transcribed verbatim. Responses were compared within and between ethnic groups. RESULTS: Each session, and ethnic group overall, developed a particular orientation to the discussion. Some mothers described the problem using single signs, while others imitated the sound or made comparisons to other illnesses. Hereditary factors were recognised by some, although all groups were concerned with environmental triggers. Responses about what to do included 'normal illness' strategies, use of health services and calls for complementary treatment. All groups were concerned about using medication every day. Expectations about the quality of life were varied, with recognition that restrictions may be based on parental beliefs about asthma, rather than asthma itself. CONCLUSION: Information from these focus groups suggests mothers know a great deal about childhood asthma even though they have no personal experience of it. Knowledge of how mothers from these ethnic backgrounds perceive asthma may facilitate doctor – patient communication with parents of children experiencing breathing difficulties