Preliminary analysis of the potential of LANDSAT imagery to study desertification

The use of LANDSAT imagery to define and delimit areas under process of desertification was investigated. Imagery for two different years (1973 and 1978) and two different seasons (dry and rainy seasons in 1976), were used to identify terrain morphology and vegetation cover. The analysis of LANDSAT interpretation, combined with geological and soil information obtained from published literature, allowed the identification of eleven ecological units which were classified corresponding to the degree of the Xique Xique region of Rio Sao Francisco

Investigating Delamination Migration in Composite Tape Laminates

A modification to a recently developed test specimen designed to investigate migration of a delamination between neighboring ply interfaces in tape laminates is presented. The specimen is a cross-ply laminated beam consisting of 40 plies with a polytetrafluoroethylene insert spanning part way along its length. The insert is located between a lower 0-degree ply (specimen length direction) and a stack of four 90-degree plies (specimen width direction). The modification involved a stacking sequence that promotes stable delamination growth prior to migration, and included a relocation of the insert from the specimen midplane to the interface between plies 14 and 15. Specimens were clamped at both ends onto a rigid baseplate and loaded on their upper surface via a piano hinge assembly, resulting in a predominantly flexural loading condition. Tests were conducted with the load-application point positioned at various locations along a specimen's span. This position affected the sequence of damage events during a test

Occasional essay: upper motor neuron syndrome in amyotrophic lateral sclerosis

The diagnosis of amyotrophic lateral sclerosis (ALS) requires recognition of both lower (LMN) and upper motor neuron (UMN) dysfunction.1 However, classical UMN signs are frequently difficult to identify in ALS.2 LMN involvement is sensitively detected by electromyography (EMG)3 but, as yet, there are no generally accepted markers for monitoring UMN abnormalities,4 the neurobiology of ALS itself, and disease spread through the brain and spinal cord,.5 Full clinical assessment is therefore necessary to exclude other diagnoses and to monitor disease progression. In part, this difficulty regarding detection of UMN involvement in ALS derives from the definition of ‘the UMN syndrome’. Abnormalities of motor control in ALS require reformulation within an expanded concept of the UMN, together with the neuropathological, neuro-imaging and neurophysiological abnormalities in ALS. We review these issues here

Predictors of Posttraumatic Stress Disorder in Chronic Low Back Pain Patients

The present study investigated the predictors of posttraumatic stress disorder (PTSD) symptom severity level in patients with chronic low back pain (CLBP). Research questions focused on whether or not patients with CLBP would evidence clinically-significant levels of PTSD, whether or not the intensity and duration of the trauma would predict PTSD symptoms, and whether or not the age of the patient and perceived uncontrollability would positively predict PTSD symptom severity level. Participants included 161 patients receiving treatment for their CLBP from several Southern California chronic pain clinics, as well as major Southern California chiropractic facilities. Data was gathered through selfreport measures for perceived pain severity, traumatic experiences, locus of control, and PTSD. Participants were placed into one of the following groups: (1) Pain Only, No Trauma, (2) Pain w/ Non-Back-Related Trauma, (3) Pain w/Back-Related Trauma, or (4) Pain w/ Combined Trauma. Results indicated that approximately 51 % of the patients in the CLBP sample evidenced clinically-significant levels of posttraumatic stress disorder symptoms. In the groups, between 25% and 77% of patients reported clinically-significant PTSD symptoms. Patients with pain and combined trauma exhibited the highest levels of PTSD symptoms in comparison to the other groups. These individuals also evidenced more: pain severity, severe diagnoses, back surgeries, treatments for their CLBP, perceived uncontrollability (external locus of control), and numerous other negative life events. Moreover, age and perceived uncontrollability positively predicted PTSD symptom severity level across all of the groups. Further, pain alone may be a sufficient trauma to predict PTSD symptoms in this population. The present study established links between a number of predictors, and a preliminary model was subsequently devised for predictors of PTSD symptom severity level in patients with CLBP. A paucity of research still remains for considering the relationship between CLBP and PTSD. The present study ascertained that both the nature of the trauma, as well as person characteristics must be considered in the assessment, diagnosis, and treatment of patients with CLBP. In addressing all possible predictors, clinicians may promote greater healing at all levels for patients with chronic low back pain