Abstract
We study the anisotropies on large angular scales which can be present in the flux of cosmic rays reaching the Earth from a population of extragalactic sources, focusing on the energy range ...between the second knee and the ankle. In this energy range the particles are significantly affected by the Galactic magnetic field, which then plays a relevant role in shaping the expected anisotropies. The Galactic magnetic field deflects the cosmic-ray trajectories and thus modifies the anisotropies present outside the halo of the Galaxy, in particular the dipolar one associated with the translational motion of the observer (Compton-Getting effect). Also, due to the Galactic rotation, in the reference frame of an observer at Earth there is an electric component of the Galactic field that produces a small change in the particles' momentum. This acceleration depends on the cosmic-ray arrival direction and it hence induces anisotropies in the flux observed in a given energy range. We analyse the expected amplitude and phase of the resulting dipolar component of the flux and discuss the possibility to explain via these effects the change in the phase of the right-ascension distribution which is observed at energies around 1 EeV.
We review some of the recent progress in our knowledge about high-energy cosmic rays, with an emphasis on the interpretation of the different observational results. We discuss the effects that are ...relevant to shape the cosmic ray spectrum and the explanations proposed to account for its features and for the observed changes in composition. The physics of air-showers is summarized and we also present the results obtained on the proton–air cross section and on the muon content of the showers. We discuss the cosmic ray propagation through magnetic fields, the effects of diffusion and of magnetic lensing, the cosmic ray interactions with background radiation fields and the production of secondary neutrinos and photons. We also consider the cosmic ray anisotropies, both at large and small angular scales, presenting the results obtained from the TeV up to the highest energies and discuss the models proposed to explain their origin.
To describe the clinical phenotype of paroxysmal extreme pain disorder (previously called familial rectal pain syndrome), an autosomal dominant condition recently shown to be a sodium channelopathy ...involving SCN9A.
An international consortium of clinicians, scientists, and affected families was formed. Clinical details of all accessible families worldwide were collected, including age at onset, features of attacks, problems between attacks, investigational results, treatments tried, and evolution over time. A validated pain questionnaire was completed by 14 affected individuals.
Seventy-seven individuals from 15 families were identified. The onset of the disorder is in the neonatal period or infancy and persists throughout life. Autonomic manifestations predominate initially, with skin flushing in all and harlequin color change and tonic attacks in most. Dramatic syncopes with bradycardia and sometimes asystole are common. Later, the disorder is characterized by attacks of excruciating deep burning pain often in the rectal, ocular, or jaw areas, but also diffuse. Attacks are triggered by factors such as defecation, cold wind, eating, and emotion. Carbamazepine is effective in almost all who try it, but the response is often incomplete.
Paroxysmal extreme pain disorder is a highly distinctive sodium channelopathy with incompletely carbamazepine-sensitive bouts of pain and sympathetic nervous system dysfunction. It is most likely to be misdiagnosed as epilepsy and, particularly in infancy, as hyperekplexia and reflex anoxic seizures.
The large scale pattern in the arrival directions of extragalactic cosmic rays that reach the Earth is different from that of the flux arriving to the halo of the Galaxy as a result of the ...propagation through the galactic magnetic field. Two different effects are relevant in this process: deflections of trajectories and (de)acceleration by the electric field component due to the galactic rotation. The deflection of the cosmic ray trajectories makes the flux intensity arriving to the halo from some direction to appear reaching the Earth from another direction. This applies to any intrinsic anisotropy in the extragalactic distribution or, even in the absence of intrinsic anisotropies, to the dipolar Compton-Getting anisotropy induced when the observer is moving with respect to the cosmic rays rest frame. For an observer moving with the solar system, cosmic rays traveling through far away regions of the Galaxy also experience an electric force coming from the relative motion (due to the rotation of the Galaxy) of the local system in which the field can be considered as being purely magnetic. This produces small changes in the particles momentum that can originate large scale anisotropies even for an isotropic extragalactic flux.
On the ultrahigh energy cosmic ray horizon Harari, D; Mollerach, S; Roulet, E
Journal of Cosmology and Astroparticle Physics,
11/2006, Letnik:
2006, Številka:
11
Journal Article
We analyse in detail the two-dimensional Kolmogorov–Smirnov test as a tool to learn about the distribution of the sources of the ultra-high energy cosmic rays. We confront, in particular, models ...based on active galactic nuclei observed in X-rays, galaxies observed in H i and isotropic distributions, discussing how this method can be used not only to reject isotropy but also to support or reject specific source models, extending results obtained recently in the literature.
We report the results of three years of the population-based, prospective Swiss NeuroPaediatric Stroke Registry (SNPSR) of children (up to 16 years) with childhood arterial ischaemic stroke (AIS1), ...neonatal stroke (AIS2), or symptomatic sinus venous thrombosis (SVT). Data on risk factors (RF), presentation, diagnostic work-up, localisation, and short-term neurological outcome were collected. 80 children (54 males) have been included, 40 AIS1, 23 AIS2, and 17 SVT. The data presented will be concentrated on AIS. The presentation for AIS1 was hemiparesis in 77% and cerebellar symptoms and seizures in 20%, respectively. AIS2 presented in 83% with seizures and in 38% with abnormality of muscle tone. Two or more RF were detected in 54%, one RF in 35%. The most prominent RF for AIS1 were infections (40%), followed by cardiopathies and coagulopathies (25% each). AIS2 were frequently related to birth problems. Neurological outcomes in AIS1 and AIS2 were moderate/severe in 45 % and 32 %, respectively. The outcome correlated significantly with the size of infarction (p = 0.013) and age at stroke (p = 0.027). The overall mortality was 6%. Paediatric stroke is a multiple risk problem, which leads to important long-term sequelae.
The study combined prospective neuropsychological and EEG results of 22 children presenting with typical benign partial epilepsy with rolandic spikes (19 participants) and occipital spikes (three ...participants). The aims were to assess the types of cognitive problems which may be encountered in this population, to evaluate the course of cognitive and learning capacities during the active phase of epilepsy, and to see if there was a correlation with paroxysmal activity on the EEG. Average age at entry in the study was 8.4 years and each child was seen 2 to 4 times over a period of 1 to 3 years. EEGs showed persistent spike foci in most cases that worsened in three cases, but there were no continuous spike–waves during sleep. No child had persistent stagnation, marked fluctuations, or a regression in cognitive abilities. Of 22 children, 21 had average IQ (>80). Eight children had school difficulties requiring special adjustment. No single cognitive profile was identified. Four children had delayed language development and eight children had transient weak scores in one isolated domain (verbal, visuospatial, memory) which improved or normalized during the course of the study with concomitant EEG improvement or normalization. In two of the three children with aggravation of the paroxysmal EEG activity, clinical changes were documented. A proportion of children with typical benign partial epilepsy with rolandic spikes showed mild, varied, and transient cognitive difficulties during the course of their epilepsy and in most cases this probably had a direct relation with the paroxysmal EEG activity.
Background
To estimate the prevalence of undernutrition among children with profound intellectual and multiple disabilities (PIMD) and to explore its influence on quality of life.
Methods
Seventy‐two ...children with PIMD (47 male; 25 female; age range 2 to 15 years 4 months; mean age 8.6, SD 3.6) underwent an anthropometric assessment, including body weight, triceps skinfold thickness, segmental measures and recumbent length. Undernutrition was determined using tricipital skinfold percentile and z‐scores of weight‐for‐height and height‐for‐age. The quality of life of each child was evaluated using the QUALIN questionnaire adapted for profoundly disabled children.
Results
Twenty‐five children (34.7%) were undernourished and seven (9.7%) were obese. Among undernourished children only eight (32 %) were receiving food supplements and two (8%) had a gastrostomy, of which one was still on a refeeding programme. On multivariate analysis, undernutrition was one of the independent predictors of lower quality of life.
Conclusion
Undernutrition remains a matter of concern in children with PIMD. There is a need to better train professionals in systematically assessing the nutritional status of profoundly disabled children in order to start nutritional management when necessary.
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