Education Reform in Democratic Spain.

Education Reform in Democratic Spain. Oliver Boyd-Barrett and Pamela O'Malley, eds. New York: Routledge, 1995. 265 pp.     

Age-Specific Mortality During the 1918 Influenza Pandemic: Unravelling the Mystery of High Young Adult Mortality

The worldwide spread of a novel influenza A (H1N1) virus in 2009 showed that influenza remains a significant health threat, even for individuals in the prime of life. This paper focuses on the unusually high young adult mortality observed during the Spanish flu pandemic of 1918. Using historical records from Canada and the U.S., we report a peak of mortality at the exact age of 28 during the pandemic and argue that this increased mortality resulted from an early life exposure to influenza during the previous Russian flu pandemic of 1889–90. We posit that in specific instances, development of immunological memory to an influenza virus strain in early life may lead to a dysregulated immune response to antigenically novel strains encountered in later life, thereby increasing the risk of death. Exposure during critical periods of development could also create holes in the T cell repertoire and impair fetal maturation in general, thereby increasing mortality from infectious diseases later in life. Knowledge of the age-pattern of susceptibility to mortality from influenza could improve crisis management during future influenza pandemics.

“The war is over – and I must go” Egon Schiele, 1890–1918.

     

Extending a Model of Shift‐Work Tolerance

The present study contributes to theory and practice through the development of a model of shift‐work tolerance with the potential to indicate interventions that reduce nurses' intention toward turnover and increase job satisfaction in hospital‐based settings. Survey data from 1257 nurses were used to conduct structural equation modeling that examine the direct and indirect effects of supervisor and colleague support, team identity, team climate, and control over working environment on time‐based work/life conflict, psychological well‐being, physical symptoms, job satisfaction, and turnover intention. The analysis of the proposed model revealed a good fit The chi‐square difference test was non‐significant (χ²(26)=338.56), the fit indices were high (CFI=.923, NFI=.918, and NNFI=.868), the distribution of residuals was symmetric and approached zero, the average standardized residual was low (AASR=.04), and the standardized RMR was. 072. In terms of the predictor variable, the final model explained 48% of the variance in turnover intention. The data revealed considerable evidence of both direct effects on adjustment and complex indirect links between levels of adjustment and work‐related social support, team identity, team climate, and control. Nurses with high supervisor and coworker support experienced more positive team climates, identified more strongly with their team, and increased their perceptions of control over their work environment. This in turn lowered their appraisals of their time‐based work/life conflict, which consequently increased their psychological well‐being and job satisfaction and reduced their physical health symptoms and turnover intention. The type of shift schedule worked by the nurses influenced levels of turnover intention, control over work environment, time‐based work/life conflict, and physical symptoms.     

Spider capture silk: performance implications of variation in an exceptional biomaterial

Spiders and their silk are an excellent system for connecting the properties of biological materials to organismal ecology. Orb-weaving spiders spin sticky capture threads that are moderately strong but exceptionally extensible, resulting in fibers that can absorb remarkable amounts of energy. These tough fibers are thought to be adapted for arresting flying insects. Using tensile testing, we ask whether patterns can be discerned in the evolution of silk material properties and the ecological uses of spider capture fibers. Here, we present a large comparative data set that allows examination of capture silk properties across orb-weaving spider species. We find that material properties vary greatly across species. Notably, extensibility, strength, and toughness all vary approximately sixfold across species. These material differences, along with variation in fiber size, dictate that the mechanical performance of capture threads, the energy and force required to break fibers, varies by more than an order of magnitude across species. Furthermore, some material and mechanical properties are evolutionarily correlated. For example, species that spin small diameter fibers tend to have tougher silk, suggesting compensation to maintain breaking energy. There is also a negative correlation between strength and extensibility across species, indicating a potential evolutionary trade-off. The different properties of these capture silks should lead to differences in the performance of orb webs during prey capture and help to define feeding niches in spiders.     

A New Species of Ctenomys (Rodentia: Ctenomyidae) from Patagonia Related to C. sociabilis

The genus Ctenomys includes a high number of taxa, with at least ten species from Patagonia and three recently described species for northeastern Chubut Province (Argentina). Ctenomys sociabilis is a social species of the genus Ctenomys and is currently distributed in the surrounding area of Sierra Cuyin Manzano (Neuquén Province), with a recently extinct population that occurred in Laguna Nahuelquir (Cushamen, Chubut Province). Molecular analyses have placed C. sociabilis at the base of Ctenomys clade, as the sister species to all other Ctenomys. Based on a morphological assessment (qualitative and quantitative) and DNA sequencing, we describe a new species of Ctenomys from Esquel, Chubut Province. Phylogenetic analysis shows the new species to be closely related to C. sociabilis, with evidence of solitary behavior. This new species is the first reported to be closely related phylogenetically to Ctenomys sociabilis at the base of the Ctenomys phylogeny. We provide anatomical comparisons between the new species and other species of Ctenomys from Patagonia, especially C. sociabilis.

     

Hepatic metabolism of vasoactive intestinal polypeptide (VIP) in the rat

Vasoactive intestinal polypeptide (VIP) is released into the portal circulation by a meal stimulus, but is rapidly cleared from plasma. Although it is known to bind to receptors on liver cells, the role of the liver in the clearance of VIP is not clearly defined. We therefore studied the disappearance of VIP in recirculating and in single pass isolated perfused rat liver (IPRL) preparations. Disappearance of added VIP was rapid in recirculating IPRL experiments with a half life of ca. 30 min. In single-pass steady-state studies in which livers were perfused at 16 ml/min for 30 min, clearance of VIP was complete (16 ml/min) at concentrations of 500 fmol/ml, but clearance fell to 3 and 1 ml/min at perfusate concentrations of 8 and 40 pmol/ml respectively. Further experiments to evaluate whether VIP was disappearing in perfusate itself demonstrated substantial metabolism of VIP in perfusate which had previously been circulated through a liver for 90 min. The products of metabolism were identical to those found in the IPRL. We conclude that VIP is rapidly cleared as it passes through the isolated perfused rat liver model with a significant proportion of clearance attributable to release of a peptidase from the liver into the perfusate.     

X-ray microanalytical detection of iron in pigmentation of oral mucosa.

A patient was referred to the Charles Clifford Dental Hospital with a grey metallic pigmentation of the hard palate. Conventional histopathological examination was inconclusive, suggesting the presence of either an ephelis (freckle) of pigmentation resulting from a stainless steel upper denture. Material from the pathological specimen was dewaxed and reembedded in Spurr's resin. Examination in the TEM revealed electron dense deposits in the cytoplasm of macrophages. Energy dispersive X-ray microanalysis demonstrated that these inclusions contained iron. The results suggested that the iron was in a form similar to haemosiderin and had arisen from the steel denture.     

Compliance with growth hormone treatment - is it a problem?

Treatments fail for a number of reasons. These include the failure of medicines at a molecular level, failure to achieve the correct diagnosis and therefore use of the correct medication, problems surrounding the doctor-patient relationship, and failure of the service to meet patients' expectations. Compliance is characteristically viewed as the major cause of treatment failures but implicit in the use of the term compliance is the reliance on an imbalance of power where the patient follows what is ordered. Such an approach is likely to lead to failure. A better model is concerned with promoting the full participation of the patient to generate a therapeutic alliance. Despite the need for parental administration and a daily therapeutic regimen there appears to be little evidence to suggest that concordance is a major problem in growth hormone therapy. This is probably because treatment administration relies on the presence of a carer and there are tangible effects. However, concordance is likely to be an issue where there is mismatch between the patient's expectations and those of the doctor. Such a situation may arise when the therapeutic margin is narrow or the therapeutic effect minimal. To resolve this situation, adequate pre-intervention discussion is essential, which should include a clear statement of short- and long-term treatment targets and the likelihood of these being achieved or not. Carefully constructed health care plans are the key and should include educational programmes, home support and regular reinforcement. When concordance problems are suspected, careful consideration needs to be given as to whether the diagnosis is correct, is the treatment really effective and appropriate and does the patient really want the treatment.     

The cover of living and dead corals from airborne remote sensing

Trends in coral cover are widely used to indicate the health of coral reefs but are costly to obtain from field survey over large areas. In situ studies of reflected spectra at the coral surface show that living and recently dead colonies can be distinguished. Here, we investigate whether such spectral differences can be detected using an airborne remote sensing instrument. The Compact Airborne Spectrographic Imager (Itres Research Ltd, Canada) was flown in two configurations: 10 spectral bands with 1-m² pixels and 6 spectral bands with 0.25-m² pixels. First, we show that an instrument with 10 spectral bands possesses adequate spectral resolution to distinguish living Porites, living Pocillopora spp., partially dead Porites, recently dead Porites (total colony mortality within 6 months), old dead (>6 months) Porites, Halimeda spp., and coralline red algae when there is no water column to confuse spectra. All substrata were distinguished using fourth-order spectral derivatives around 538 nm and 562 nm. Then, at a shallow site (Tivaru) at Rangiroa Atoll, Tuamotu Archipelago (French Polynesia), we show that live and dead coral can be distinguished from the air to a depth of at least 4 m using first- and fourth-order spectral derivatives between 562–580 nm. However, partially dead and recently dead Porites colonies could not be distinguished from an airborne platform. Spectral differences among substrata are then exploited to predict the cover of reef substrata in ten 25-m² plots at nearby Motu Nuhi (max depth 8 m). The actual cover in these plots was determined in situ using quadrats with a 0.01-m² grid. Considerable disparity occurred between field and image-based measures of substrate cover within individual 25-m² quadrats. At this small scale, disparity, measured as the absolute difference in cover between field and remote-sensing methods, reached 25% in some substrata but was always less than 10% for living coral (99% of which consisted of Porites spp.). At the scale of the reef (all ten 25-m² quadrats), however, disparities in percent cover between imagery and field data were less than 10% for all substrata and extremely low for some classes (e.g. <3% for living Porites, recently dead Porites and Halimeda). The least accurately estimated substrata were sand and coralline red algae, which were overestimated by absolute values 7.9% and 6.6%, respectively. The precision of sampling was similar for field and remote-sensing methods: field methods required 19 plots to detect a 10% difference in coral cover among three reefs with a statistical power of 95%. Remote-sensing methods required 21 plots. However, it took 1 h to acquire imagery over 92,500 m² of reef, which represents 3,700 plots of 25 m² each, compared with 3 days to survey 10 such plots underwater. There were no significant differences in accuracy between 1-m² and 0.25-m² image resolutions, suggesting that the advantage of using smaller pixels is offset by reduced spectral information and an increase in noise (noise was observed to be 1.6–1.8 times greater in 0.25-m² pixels). We show that airborne remote sensing can be used to monitor coral and algal cover over large areas, providing that water is shallow and clear, and that brown fleshy macroalgae are scarce, that depth is known independently (e.g. from sonar survey).