Persistent effects of pre-Columbian plant domestication on Amazonian forest composition.

The extent to which pre-Columbian societies altered Amazonian landscapes is hotly debated. We performed a basin-wide analysis of pre-Columbian impacts on Amazonian forests by overlaying known archaeological sites in Amazonia with the distributions and abundances of 85 woody species domesticated by pre-Columbian peoples. Domesticated species are five times more likely than nondomesticated species to be hyperdominant. Across the basin, the relative abundance and richness of domesticated species increase in forests on and around archaeological sites. In southwestern and eastern Amazonia, distance to archaeological sites strongly influences the relative abundance and richness of domesticated species. Our analyses indicate that modern tree communities in Amazonia are structured to an important extent by a long history of plant domestication by Amazonian peoples.

Predicting pre-Columbian anthropogenic soils in Amazonia.

The extent and intensity of pre-Columbian impacts on lowland Amazonia have remained uncertain and controversial. Various indicators can be used to gauge the impact of pre-Columbian societies, but the formation of nutrient-enriched terra preta soils has been widely accepted as an indication of long-term settlement and site fidelity. Using known and newly discovered terra preta sites and maximum entropy algorithms (Maxent), we determined the influence of regional environmental conditions on the likelihood that terra pretas would have been formed at any given location in lowland Amazonia. Terra pretas were most frequently found in central and eastern Amazonia along the lower courses of the major Amazonian rivers. Terrain, hydrologic and soil characteristics were more important predictors of terra preta distributions than climatic conditions. Our modelling efforts indicated that terra pretas are likely to be found throughout ca 154 063 km(2) or 3.2% of the forest. We also predict that terra preta formation was limited in most of western Amazonia. Model results suggested that the distribution of terra preta was highly predictable based on environmental parameters. We provided targets for future archaeological surveys under the vast forest canopy and also highlighted how few of the long-term forest inventory sites in Amazonia are able to capture the effects of historical disturbance.

Abundant and stable char residues in soils: implications for soil fertility and carbon sequestration.

Large-scale soil application of biochar may enhance soil fertility, increasing crop production for the growing human population, while also sequestering atmospheric carbon. But reaching these beneficial outcomes requires an understanding of the relationships among biochar's structure, stability, and contribution to soil fertility. Using quantitative (13)C nuclear magnetic resonance (NMR) spectroscopy, we show that Terra Preta soils (fertile anthropogenic dark earths in Amazonia that were enriched with char >800 years ago) consist predominantly of char residues composed of ~6 fused aromatic rings substituted by COO(-) groups that significantly increase the soils' cation-exchange capacity and thus the retention of plant nutrients. We also show that highly productive, grassland-derived soils in the U.S. (Mollisols) contain char (generated by presettlement fires) that is structurally comparable to char in the Terra Preta soils and much more abundant than previously thought (~40-50% of organic C). Our findings indicate that these oxidized char residues represent a particularly stable, abundant, and fertility-enhancing form of soil organic matter.

Tonsillolith--report of an unusual case.

Tonsilloliths are rare concretions found in the tonsillar crypt. They are usually single and unilateral, but occasionally may be multiple or bilateral. This report describes a case of a 47-year-old woman whose radiography revealed one radiopaque image located in the right ramus of the mandible. The patient revealed a history of slight dysphagia, halitosis and swallowing pain with a foreign body sensation. Her medical history revealed a tonsillectomy when she was eight years old and the removal of the uvula because of sleep apnoea six years ago. Computer tomography showed a delimited and calcified oval image measuring 0.6 x 0.6 cm. The tonsillar concretion might have been formed because of a calcification of the lymphoid tissue. On the patient's request, surgical excision was not performed and she will be monitored due to the tendency of such lesions to grow.

Spinal cord injury: patients who had an accident, walked but became spinal paralysed.

Out of 1410 patients admitted to the spinal cord injury unit (SARAH) for rehabilitation during a 10-year period (1981-90) 10 had a missed spinal trauma lesion and became paralysed after having overcome the initial injuries and being allowed to walk. Patients were admitted to hospital with a history of being able to walk after an accident and subsequently developing a neurological deficit. Seven patients had radiological findings compatible with instability of the spine. Four had a head injury with coma and an undetected spinal fracture at the first evaluation in the emergency room. Other associated factors were: spinal stenosis, prolapsed disc, infection, foreign bodies, procedures for reduction and stabilization of the fractured spine. We emphasize the need for very careful clinical study and investigation for the diagnosis of multiinjured patients, especially when there is a concurrent brain injury.

Pyrexia in hospitalised spinal cord injury patients.

To discover the frequency of pyrexia in spinal cord injury (SCI) patients in the Hospital for Medicine of the Locomotor System (HMLS/SARAH), a review study was undertaken. For a period of 3 months, all new episodes of fever were recorded. During the study 221.3 patients/month were observed. The age ranged from 14 to 60 years and time of lesion from 1 to 6,264 days: 85 patients were paraplegia or paraparetic, and 44 tetraplegic or tetraparetic. At the beginning of the study 10.8% of the patients had fever. During follow up, we observed a rate of 33.9 new incidences per 100 patients/month. In 77.3% only one cause was identified, and in 8% no cause could be defined. The commonest causes were urinary tract infection (UTI) (44.3%), and soft tissue infections (11.4%). Frequent causes of fever in the acute stage other than UTI were complications related to the initial trauma and thromboembolic disease (p < 0.05). These results demonstrate the high incidence of fever in patients with SCI, in addition to providing a useful approach for diagnosis and management.

Traumatic injury to the spinal cord. Prevalence in Brazilian hospitals.

Traumatic spinal cord lesions have a worldwide high morbidity and mortality, and in many developed countries the problem has received special attention, based on epidemiological studies. In Brazil these studies have been restricted to institutional data. In 1988 a survey conducted by the Integrated System of Traumatology and Orthopaedics, covering 36 public hospitals from 7 Brazilian capitals, revealed a point prevalence of 8.6% (108 patients) with spinal cord injury, aged from 6-56 years; 81% were men. The most frequent causes were traffic accidents (42%), firearms (27%) and falling from heights (15%). The main complications were pressure ulcers (54%) and urinary infections (32%).

Experience with a spinal cord unit in Brasilia, Brazil.

We have analysed our experiences in a Spinal Cord Unit in Brasilia, Brazil in the last 5 years (1982-1986). There were 738 outpatients and 243 inpatients. One hundred and six patients were operated on by the neurosurgical staff, and the indications for operation are discussed. Some patients showed neurological recovery with surgery and some without surgery. Patients with a complete neurological deficit on admission did not show any improvement, and those with a severe but incomplete deficit showed improvement with surgery (18%), which was better than those without an operation. We conclude that a surgical procedure seems to be indicated in those with a comminuted, or with an unstable fracture, if there is an incomplete neurological deficit with an unreduced spinal deformity. There was a possibility of recovery of some nerve root function. The goal of surgical treatment is to restore and maintain the anatomical relationships between the spinal canal, spinal cord and nerve roots with the simplest possible surgical procedure, returning the patient as soon as possible to his functional capacity and social life.