My experience with helicopters

The author recounts his experiments with helicopters. The object of his investigations was to remain stationary in the air for five minutes and to make a closed flight at low altitude. Some of the topics discussed include stabilization, horizontal flight, and directional control

Perineuronal satellite neuroglia in the telencephalon of New Caledonian crows and other Passeriformes: evidence of satellite glial cells in the central nervous system of healthy birds?

Glia have been implicated in a variety of functions in the central nervous system, including the control of the neuronal extracellular space, synaptic plasticity and transmission, development and adult neurogenesis. Perineuronal glia forming groups around neurons are associated with both normal and pathological nervous tissue. Recent studies have linked reduction in the number of perineuronal oligodendrocytes in the prefrontal cortex with human schizophrenia and other psychiatric disorders. Therefore, perineuronal glia may play a decisive role in homeostasis and normal activity of the human nervous system.Here we report on the discovery of novel cell clusters in the telencephala of five healthy Passeriforme, one Psittaciform and one Charadriiforme bird species, which we refer to as Perineuronal Glial Clusters (PGCs). The aim of this study is to describe the structure and distribution of the PGCs in a number of avian species.PGCs were identified with the use of standard histological procedures. Heterochromatin masses visible inside the nuclei of these satellite glia suggest that they may correspond to oligodendrocytes. PGCs were found in the brains of nine New Caledonian crows, two Japanese jungle crows, two Australian magpies, two Indian mynah, three zebra finches (all Passeriformes), one Southern lapwing (Charadriiformes) and one monk parakeet (Psittaciformes). Microscopic survey of the brain tissue suggests that the largest PGCs are located in the hyperpallium densocellulare and mesopallium. No clusters were found in brain sections from one Gruiform (purple swamphen), one Strigiform (barn owl), one Trochiliform (green-backed firecrown), one Falconiform (chimango caracara), one Columbiform (pigeon) and one Galliform (chick).Our observations suggest that PGCs in Aves are brain region- and taxon-specific and that the presence of perineuronal glia in healthy human brains and the similar PGCs in avian gray matter is the result of convergent evolution. The discovery of PGCs in the zebra finch is of great importance because this species has the potential to become a robust animal model in which to study the function of neuron-glia interactions in healthy and diseased adult brains

NACA Technical Memorandums

The author recounts his experiments with helicopters. The object of his investigations was to remain stationary in the air for five minutes and to make a closed flight at low altitude. Some of the topics discussed include stabilization, horizontal flight, and directional control

Talassemi i Sverige – Behandlingsmål och uppföljning varierar kraftigt.

A survey of transfusion-dependent thalassaemia was conducted to study epidemiology, treatment and follow-up routines as a basis for future discussions. Questionnaires were sent to 97 clinics in Sweden. Responses were submitted by 86 of the clinics, 21 of which cared for 32 patients (18 children, 14 adults; i.e.only one or a few patients per hospital). Ten of those 32 (33 procent) patients were born in Sweden. Children were given transfusions more frequently and had higher mean haemoglobin. Iron overload was treated with deferoxamine in 84 procent of the patients and with deferiprone in 44 procent. The mean ferritin concentration was 1670 g/l, although 34 procent (11/32) had levels > 2000 g/l. Follow-up monitoring of iron overload varied considerably, and ferritin analysis was the only routine examination in 28 procent of the patients. Furthermore, 47 procent had no regular follow-up evaluations of endocrine organ function