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Geophysical survey and excavations from 2010–2016 at Lawrenz Gun Club (11CS4), a late pre-Columbian village located in the central Illinois River valley in Illinois, identified 10 mounds, a central plaza, and dozens of structures enclosed within a stout 10 hectare bastioned palisade. Nineteen radiocarbon (14C) measurements were taken from single entities of wood charcoal, short-lived plants, and animal bones. A site chronology has been constructed using a Bayesian approach that considers the stratigraphic contexts and feature formation processes. The village was host to hundreds of years of continuous human activity during the Mississippi Period. Mississippian activity at the site is estimated to have begun in cal AD 990–1165 (95% probability), ended in cal AD 1295–1450 (95% probability), and lasted 150–420 yr (95% probability) in the primary Bayesian model with similar results obtained in two alternative models. The palisade is estimated to have been constructed in cal AD 1150–1230 (95% probability) and was continuously repaired and rebuilt for 15–125 yr (95% probability), probably for 40–85 yr (68% probability). Comparison to other studies demonstrates that the bastioned palisade at Lawrenz was one of the earliest constructed in the midcontinental United States.
Stigma can have a negative impact on help-seeking behaviour, treatment adherence and recovery of people with mental disorders. This study aimed to determine the feasibility of the WHO Mental Health Treatment Gap Interventions Guidelines (mhGAP-IG) to reduce stigma in face-to-face contacts during interventions for specific DSM-IV/ICD 10 diagnoses over a 6-month period.
This study was conducted in 20 health facilities across Makueni County in southeast Kenya which has one of the poorest economies in the country and has no psychiatrist or clinical psychologist. We recruited 2305 participants from the health facilities catchment areas that had already been exposed to community mental health services. We measured stigma using DISC-12 at baseline, followed by training to the health professionals on intervention using the WHO mhGAP-IG and then conducted a follow-up DISC-12 assessment after 6 months. Proper management of the patients by the trained professionals would contribute to the reduction of stigma in the patients.
There was 59.5% follow-up at 6 months. Overall, there was a significant decline in ‘reported/experienced discrimination’ following the interventions. A multivariate linear mixed model regression indicated that better outcomes of ‘unfair treatment’ scores were associated with: being married, low education, being young, being self-employed, higher wealth index and being diagnosed with depression. For ‘stopping self’ domain, better outcomes were associated with being female, married, employed, young, lower wealth index and a depression diagnosis. In regards to ‘overcoming stigma’ domain; being male, being educated, employed, higher wealth index and being diagnosed with depression was associated with better outcomes.
The statistically significant (p < 0.05) reduction of discrimination following the interventions by trained health professionals suggest that the mhGAP-IG may be a useful tool for reduction of discrimination in rural settings in low-income countries.
Lead isotope analyses of 50 Irish Chalcolithic and Early Bronze Age gold artefacts favour a gold source in southern Ireland. However when combined with major element analysis, the artefacts are not consistent with any Irish gold deposit analysed to date. Understanding the lead isotope signatures of ore deposits within a study region allows informed inferences to be drawn regarding the likelihood that an unanalysed ore deposit was exploited in the past. If an Irish gold source is assumed, then the gold is most likely to have originated from deposits hosted by Old Red Sandstone in the Variscan ore field of south-west Ireland. However, based on our current understanding of mineralisation in the region, this scenario is considered unlikely. A non-Irish source for the gold is therefore preferred – a scenario that may favour cosmologically-driven acquisition, ie, the deliberate procurement of a material from distant or esoteric sources. Available geochemical data, combined with current archaeological evidence, favour the alluvial deposits of south-west Britain as the most likely source of the gold.
Previous research has found that many patients with anorexia nervosa (AN) are unable to maintain normal weight after weight restoration. The objective of this study was to identify variables that predicted successful weight maintenance among weight-restored AN patients.
Ninety-three patients with AN treated at two sites (Toronto and New York) through in-patient or partial hospitalization achieved a minimally normal weight and were then randomly assigned to receive fluoxetine or placebo along with cognitive behavioral therapy (CBT) for 1 year. Clinical, demographic and psychometric variables were assessed after weight restoration prior to randomization and putative predictors of successful weight maintenance at 6 and 12 months were examined.
The most powerful predictors of weight maintenance at 6 and 12 months following weight restoration were pre-randomization body mass index (BMI) and the rate of weight loss in the first 28 days following randomization. Higher BMI and lower rate of weight loss were associated with greater likelihood of maintaining a normal BMI at 6 and 12 months. An additional predictor of weight maintenance was site; patients in Toronto fared better than those in New York.
This study found that the best predictors of weight maintenance in weight-restored AN patients over 6 and 12 months were the level of weight restoration at the conclusion of acute treatment and the avoidance of weight loss immediately following intensive treatment. These results suggest that outcome might be improved by achieving a higher BMI during structured treatment programs and on preventing weight loss immediately following discharge from such programs.
The aim of this review is to consider the potential mechanisms birds may use to manipulate the sex of their progeny, and the possible role played by maternal hormones. Over the past few years there has been a surge of reports documenting the ability of birds to overcome the rigid process of chromosomal sex determination. However, while many of these studies leave us in little doubt that mechanisms allowing birds to achieve this feat do exist, we are only left with tantalizing suggestions as to what the precise mechanism or mechanisms may be. The quest to elucidate them is made no easier by the fact that a variety of environmental conditions have been invoked in relation to sex manipulation, and there is no reason to assume that any particular mechanism is conserved among the vast diversity of species that can achieve it. In fact, a number of intriguing proposals have been put forward. We begin by briefly reviewing some of the most recent examples of this phenomenon before highlighting some of the more plausible mechanisms, drawing on recent work from a variety of taxa. In birds, females are the heterogametic sex and so non-Mendelian segregation of the sex chromosomes could conceivably be under maternal control. Another suggestion is that follicles that ultimately give rise to males and females grow at different rates. Alternatively, the female might selectively abort embryos or ‘dump lay’ eggs of a particular sex, deny certain ova a chance of ovulation, fertilization or zygote formation, or selectively provision eggs so that there is sex-specific embryonic mortality. The ideas outlined in this review provide good starting points for testing the hypotheses both experimentally (behaviourally and physiologically) and theoretically.
The external and internal morphology of the adult stage of the nematode parasite Heligmosomoides polygyrus.
The mating behaviour of the adult worms.
The distribution of worms in the small intestine and the selection of a preferred site.
Intestinal nematode parasites are very common in mammalian hosts and are responsible for human disease as well as for losses to the agricultural industries through their effects on domestic animals. H. polygyrus (Fig. 1.15.1) is an intestinal nematode parasite of mice that is very easy to maintain in the laboratory and provides convenient material to demonstrate some of the adaptations that have evolved in nematodes for survival in their hosts.
Unfortunately, this parasite has been the subject of a longstanding taxonomic debate as to the most appropriate name for the species. These problems are discussed by Behnke et al. (1991) and the reader is referred to this publication for further details. The approach used here is that the alternative name for the species, Nematospiroides dubius, is no longer used. H. polygyrus bakeri is the strain maintained in domestic/laboratory mice, Mus musculus. In Europe, however, wild field or wood mice, Apodemus sylvaticus, carry the subspecies called H.p. polygyrus and voles, Clethrionomys glareolus, H. glareoli. All of these, if available, can provide useful teaching material. This protocol is based on the laboratory passaged subspecies H. polygyrus bakeri.
The trematode Fasciola hepatica secretes
a number of cathepsin L-like proteases that are proposed
to be involved in feeding, migration, and immune evasion
by the parasite. To date, six full cDNA sequences encoding
cathepsin L preproproteins have been identified. Previous
studies have demonstrated that one of these cathepsins
(L2) is unusual in that it is able to cleave substrates
with a proline in the P2 position, translating
into an unusual ability (for a cysteine proteinase) to
clot fibrinogen. In this study, we report the sequence
of a novel cathepsin (L5) and compare the substrate specificity
of a recombinant enzyme with that of recombinant cathepsin
L2. Despite sharing 80% sequence identity with cathepsin
L2, cathepsin L5 does not exhibit substantial catalytic
activity against substrates containing proline in the P2
position. Molecular modeling studies suggested that a single
amino acid change (L69Y) in the mature proteinases may
account for the difference in specificity at the S2
subsite. Recombinant cathepsin L5/L69Y was expressed in
yeast and a substantial increase in the ability of this
variant to accommodate substrates with a proline residue
in the P2 position was observed. Thus, we have
identified a single amino acid substitution that can substantially
influence the architecture of the S2 subsite
of F. hepatica cathepsin L proteases.
α1-Antitrypsin deficiency, which
can lead to both emphysema and liver disease, is a result
of the accumulation of α1-antitrypsin polymers
within the hepatocyte. A wealth of biochemical and biophysical
data suggests that α1-antitrypsin polymers
form via insertion of residues from the reactive center
loop of one molecule into the β-sheet of another. However,
this long-standing hypothesis has not been confirmed by
direct structural evidence. Here, we describe the first
crystallographic evidence of a β-strand linked polymer
form of α1-antitrypsin: the crystal structure
of a cleaved α1-antitrypsin polymer.
This paper was first published in 1957 (Vol. 10, p. 398). It is followed by comments from David Page.
With the comparative absence of navigation aids in the earlier days of flying, up to about ten years ago, the navigator was constantly engaged in associating observations, calculations and chartwork in what was essentially a high-class guessing game. The low speeds (just over 100 knots on flying boats and just under 200 knots on landplanes) provided enough time for this rather intriguing exercise to be carried out in a fairly relaxed atmosphere, conducive to an individualistic approach that could be justified by results. The navigator's performance was largely (at that stage of aviation) judged on the neatness of his plotting, the accuracy of ETA'S and the absence of late course corrections before arriving at destination or a check point. If there is anything in the view that navigation is an art, this particular yardstick certainly induced considerable artifice in the navigator.
We review the processes and mechanisms by which voltage offsets occur in the hysteresis loop of ferroelectric materials. Simply stated, voltage shifts arise from nearinterfacial charge trapping in the ferroelectric. We show that the impetus behind voltage shifts in ferroelectric capacitors is the net polarization, with the net polarization being determined by the perovskite and the aligned defect-dipole components. Some common defect-dipoles in the PZT system are lead vacancy-oxygen vacancy complexes. One way to change the net polarization in the ferroelectric is to subject the PZT capacitor to a dc bias at elevated temperature; this process is spectroscopically shown to align defect-dipoles along the direction of the applied electric field. The alignment of defect-dipoles can strongly impact several material properties. One such impact is that it can lead to enhanced voltage shifts (imprint). It is proposed that the net polarization determines the spatial location of the asymmetrically trapped charge that are the cause for the voltage shifts. An enhanced polarization at one electrode interface can lead to larger voltage shifts since it lowers the electrostatic potential well for electron trapping, i.e., more electron trapping can occur. Defect-dipole alignment is also shown to increase the UV sensitivity of the ferroelectric.
The common whelk, Buccinum undatum L., was selected as a model host-parasite system in a seasonal study at an ‘accumulating’ sewage-sludge dump-site in the Firth of Clyde, Scotland, where marked spatial concentration gradients exist for a variety of trace contaminants in the sediments. A total of 2808 whelks was examined from seven sites over 18 months. The prevalence of larval digenean parasites increased significantly with distance from the dump site from approximately 2% on its periphery to 15.1% at a reference site 3 km from the centre. At a second reference site, 13 km from the dumping area, 19.7% of Buccinum were parasitized. The effects of site, season, sex and parasitism on growth and condition of Buccinum and exposure to sewage sludge on the age-prevalence relationship and host response to infection were examined. Age-frequency distributions of Buccinum were used to compare various sources of mortalities (natural, fishing, pollution and parasite-induced). Patterns in parasite prevalence recorded at the dump site were not correlated with any natural environmental or host-related factors that were examined. The gradient in parasitism in Buccinum is considered to result principally from the toxic effects of trace metals on the miracidium, reducing parasite transmission to the molluscan host. The Bucrinum-parasite system may therefore provide a sensitive and valuable biologically-based index of the dispersal of these contaminants around the sewage-sludge dump-site, and may have wider applications for marine environmental monitoring.
Development of the inflammatory response of rainbow trout to experimental infections with Diphyllobothrium dendriticum plerocercoids is described using light and electron microscopy. The cellular response to plerocercoids occurred within 2 weeks post-infection (p.i.). This was followed by an increase in leucocyte numbers during weeks 3–6 p.i., with full encapsulation of plerocercoids by week 6 p.i. Neutrophils were the first leucocytes to engage the developing plerocercoid, followed by large influxes of macrophages which transformed into epithelioid cells. With longer times p.i. the accumulation of different leucocyte types increased, and a blood vascular network developed. Full development of the composite cyst was characterized by fibroplasia, particularly at the periphery of the cyst, and the subsequent deposition of a collagenous tissue matrix. Enzyme-linked immunosorbent assay (ELISA) examination of serum samples taken over the 20 week period showed that specific anti-D. dendriticum antibody titres were first detected at 5 weeks p.i. and increased to a maximum by 11 weeks p.i.
Novel porous amorphous/crystalline superlattices were produced by the etching of mesas containing superlattices of alternating layers of Si and Si1−xGex. These layers were grown by molecular beam epitaxy on (100) Si substrates and etched in an aqueous HF:HNO3 solution. Preferential attack and amorphization of the Si1−x Gex layers was observed, leading to the formation of alternating layers of single crystal Si and porous amorphous Si1−xGex. The etchant is highly selective and it was possible to etch extremely thin (5nm) Si0.7Ge0.3 layers between 30nm Si layers. Complete conversion of the Si0.7Ge0.3 layers to the porous amorphous state was seen in lμm wide mesas. The role of composition and thickness of the Si1−xGex layers was studied. The variation in the lateral etch depths of the Si1−xGex layers in the superlattices demonstrates that lattice strain in these layers is an important factor in the selectivity of the etch process. As the thickness of the Si1−xGex layers is decreased, transport of the etchant to and the etch products from the reaction front is reduced, limiting the penetration of the etching process. The porosities of these etched Si1−xGex layers were determined to be comparable to measured values for thick etched alloy layers.
Molecular beam epitaxy of silicides is conventionally carried out at temperatures ≤500°C, with stoichiometric Si:metal flux ratios or deposition of pure metal. We have found novel growth modes for epitaxial CoSi2 at high temperatures coupled with Si-rich flux ratios or low deposition rates. In the first of these modes, codeposition of metal and Si at 600-800°C with excess Si leads to the formation of epitaxial silicide columns surrounded by single-crystal Si. During the initial stages of the deposition, the excess Si grows homoepitaxially in between the silicide, which forms islands, so that the lateral growth of the islands is confined. Once a template layer is established by this process, columns of silicide form as a result of selective epitaxy of silicide on silicide and Si on Si. This growth process allows nanometer control over silicide particles in three dimensions. In the second of these modes, a columnar silicide seed layer is used as a template to nucleate subsurface growth of CoSi2. With a 100 nm Si layer covering CoSi2 seeds, Co deposited at 800°C and 0.01 nm/s diffuses down to grow on the buried seeds rather than nucleating surface silicide islands. For thicker Si caps or higher deposition rates, the surface concentration of Co exceeds the critical concentration for nucleation of islands, preventing this subsurface growth mode from occurring. Using this technique, single-crystal layers of CoSi2 buried under single-crystal Si caps have been grown.
The nature of light-emitting porous Si layers produced by non-anodic stain etching of p-type (100) Si substrates is studied. The layers were characterized by transmission electron microscopy as being amorphous in nature. X-ray photoelectron spectroscopy and electron spin resonance measurements show these layers to be composed mainly of a-Si. The formation mechanism of the a-Si is explored using by stain etching SiGe ‘marker’ layers within epitaxially grown Si films and by high temperature annealing. These experiments provide strong evidence for a spontaneous crystalline-amorphous phase transformation during the etching process.
A candidate GeSi buffer layer structure suitable for strain-symmetrised GeSi/Si superlattice overgrowth is grown by molecular-beam epitaxy and its strain state characterised using microdiffraction in a dedicated scanning transmission electron microscope. The structure consists of five alloy layers of increasing Ge concentration grown on a Si (100) substrate, with all but the last annealed at high temperature. Analysis of higher order Laue zone deficit lines in the microdiffraction patterns acquired from each layer indicate that relaxation is complete in all the layers. Images of the structure in the transmission electron microscope show good crystallinity of the final layer with low concentrations of threading dislocations.