4,835 research outputs found
Household decision-making about delivery in health facilities: evidence from Tanzania.
This study investigated how partners' perceptions of the healthcare system influence decisions about delivery-location in low-resource settings. A multistage population-representative sample was used in Kasulu district, Tanzania, to identify women who had given birth in the last five years and their partners. Of 826 couples in analysis, 506 (61.3%) of the women delivered in the home. In multivariate analysis, factors associated with delivery in a health facility were agreement of partners on the importance of delivering in a health facility and agreement that skills of doctors are better than those of traditional birth attendants. When partners disagreed, the opinion of the woman was more influential in determining delivery-location. Agreement of partners regarding perceptions about the healthcare system appeared to be an important driver of decisions about delivery-location. These findings suggest that both partners should be included in the decision-making process regarding delivery to raise rates of delivery at facility
Riparian woodland condition in relation to lippia (Phyla canescens (Kunth) Greene) and fire management, southern Queensland
The implementation of inappropriate management regimes encourages alien species invasion into native ecosystems. Disturbances, such as fire, flooding and grazing, create a unique window of opportunity for invasive species to colonise areas not previously invaded. Fire regimes can be changed through the introduction of foreign species and may induce detrimental ecosystem effects including increased tree mortality, an increase in bare ground and further invasion by foreign species.
Phyla canescens (lippia) is an invasive introduced species covering over 5.3 million hectares of the Murray-Darling Basin. Many potential control methods have been attempted. However, the response of lippia to fire as a potential management tool has not previously been studied.
The general question of this research was: what is the effect of a prescribed fire on lippia, the vegetation structural components and the soil seed bank of a vegetation remnant in a highly modified agricultural landscape? This research examined the following specific hypotheses: that there is no difference in the abundance of lippia between burnt and unburnt treatments, six months after a prescribed burn; that there is no difference in the abundance of other vegetative structural components between burnt and unburnt woodlands, six months after a prescribed burn; that the fire has resulted in no change in the seedling emergence of lippia seeds stores in the soil seed bank; and, that the fire has resulted in no change of pseudo-species (not taxonomically identified species) richness within the seed bank.
Ten sites, (5 burnt, 5 unburnt) were sampled within each of the two woodlands: Eucalyptus camaldulensis and Eucalyptus populnea, six months after a prescribed burn. At each site, a 500 m2 quadrat was established to determine general disturbance measures (using a 0–4 scoring method) and the abundance and percentage cover of vegetative structural components. Within each 500 m2 quadrat, the density of the following vegetative structural components were
measured: trees > 20 m; trees 10–20 m; trees 20 m; standing stags 10–20 m; standing stags < 10 m; stumps; logs 6–13 cm; logs 13–35 cm; logs 35–90 cm; and logs 90–150 cm. The percent cover of each of the following vegetative structural components was also
measured: trees; stags; stumps; logs; grasses/sedges; herbs/forbs; lippia; lippia litter; fine litter; bare ground. Within each 500 m2 quadrat, eight 70 cm2 sub-quadrats were placed along a 16 m transect to determine the cover abundance of lippia, grasses and forbs at a finer scale. Soil samples were also collected at each site for the glasshouse seed germination trial. Samples were
kept in the glasshouse for 14 weeks to determine total germination and pseudo-species richness of each site and treatment. Independent T-tests determined whether there were any significant differences of variables between treatments. The Levene’s Test for Homogeneity was used to
determine homogeneity.
There were no significant differences in the abundance and cover of lippia or vegetation structural components between burnt and unburnt woodlands, six months after a prescribed burn at either the broad (500 m2) or finer scale (70 cm2) (T-test, p > 0.05). The only exception to this finding was a significant difference in forb cover between burnt and unburnt Eucalyptus populnea woodlands (T-test, p < 0.05). There were no significant differences in seedling emergence or pseudo-species richness between burnt and unburnt treatments within each
woodland (T-test, p > 0.05).
This research shows that fire may not be a suitable control method for lippia invasion. The results found for structural components and the seedling germination trial were consistent with previous literature. Lippia’s response to fire in this study and the lack of positive effect that fire had on the invasive weed at St Ruth Reserve, has begun to fill an identified knowledge gap in the control methods for lippia. This study shows that fire may not be a useful management tool for lippia
Mitral valve infective endocarditis following device occlusion of a coronary artery fistula
A three year old girl, with a right coronary artery fistula and signs of a hyperdynamic circulation, underwent uncomplicated closure of the fistula using an occluding device introduced via the femoral arterial route and covered with appropriate antibiotics. Two months later she presented with a persistent fever, signs of infective endocarditis (IE) and embolic phenomena in the left lower limb. Mitral valve endocarditis was confirmed immediately and treated effectively. However, initial ultrasound and doppler did not show the femoral artery thrombo-occlusion that was only confirmed on magnetic resonance angiography (MRA) one month later. This case highlights the usefulness of MRA in diagnosing suspected vessel occlusion in young children, and is in keeping with the latest NICE guidelines that suggest that prophylactic antibiotics do not always prevent IE. Parent and patient education on ‘what to look out for’, combined with careful clinical vigilance is paramount in the early detection of IE with a consequent reduction in morbidity and mortality.peer-reviewe
A roadmap to integrate astrocytes into Systems Neuroscience.
Systems neuroscience is still mainly a neuronal field, despite the plethora of evidence supporting the fact that astrocytes modulate local neural circuits, networks, and complex behaviors. In this article, we sought to identify which types of studies are necessary to establish whether astrocytes, beyond their well-documented homeostatic and metabolic functions, perform computations implementing mathematical algorithms that sub-serve coding and higher-brain functions. First, we reviewed Systems-like studies that include astrocytes in order to identify computational operations that these cells may perform, using Ca2+ transients as their encoding language. The analysis suggests that astrocytes may carry out canonical computations in a time scale of subseconds to seconds in sensory processing, neuromodulation, brain state, memory formation, fear, and complex homeostatic reflexes. Next, we propose a list of actions to gain insight into the outstanding question of which variables are encoded by such computations. The application of statistical analyses based on machine learning, such as dimensionality reduction and decoding in the context of complex behaviors, combined with connectomics of astrocyte-neuronal circuits, is, in our view, fundamental undertakings. We also discuss technical and analytical approaches to study neuronal and astrocytic populations simultaneously, and the inclusion of astrocytes in advanced modeling of neural circuits, as well as in theories currently under exploration such as predictive coding and energy-efficient coding. Clarifying the relationship between astrocytic Ca2+ and brain coding may represent a leap forward toward novel approaches in the study of astrocytes in health and disease
Sclerostin's role in bone's adaptive response to mechanical loading
Mechanical loading is the primary functional determinant of bone mass and architecture, and osteocytes play a key role in translating mechanical signals into (re)modelling responses. Although the precise mechanisms remain unclear, Wnt signalling pathway components, and the anti-osteogenic canonical Wnt inhibitor Sost/sclerostin in particular, play an important role in regulating bone's adaptive response to loading. Increases in loading-engendered strains down-regulate osteocyte sclerostin expression, whereas reduced strains, as in disuse, are associated with increased sclerostin production and bone loss. However, while sclerostin up-regulation appears to be necessary for the loss of bone with disuse, the role of sclerostin in the osteogenic response to loading is more complex. While mice unable to down-regulate sclerostin do not gain bone with loading, Sost knockout mice have an enhanced osteogenic response to loading. The molecular mechanisms by which osteocytes sense and transduce loading-related stimuli into changes in sclerostin expression remain unclear but include several, potentially interlinked, signalling cascades involving periostin/integrin, prostaglandin, estrogen receptor, calcium/NO and Igf signalling. Deciphering the mechanisms by which changes in the mechanical environment regulate sclerostin production may lead to the development of therapeutic strategies that can reverse the skeletal structural deterioration characteristic of disuse and age-related osteoporosis and enhance bones' functional adaptation to loading. By enhancing the osteogenic potential of the context in which individual therapies such as sclerostin antibodies act it may become possible to both prevent and reverse the age-related skeletal structural deterioration characteristic of osteoporosis
Feromones: el paper de l'olor en la comunicació animal
Chemical perception is considered one of the first senses used as a communication system between living organisms. Such communication is based on the emission of signals between a sender and a receiver; if the communication is chemical, these signals are called pheromones. These signals have evolved via natural selection through a mechanism known as ritualization, which converts cues (which are not adapted to communication and which the receiver picks up regardless of the interests of the sender) into signals (information that the sender transmits as an adaptative response to its previously developed perception of the receiver). When communication has evolved between actors (sender and receiver) with common interests, the honesty of the signal is taken for granted, since both want the same thing (i.e., there is no reason to deceive). If the actors have conflicting interests, however, then the possibility of deception seeps into the possible array of adaptations. This can be observed in the case of communicative mimicry. However, in other situations natural selection imposes conditions that screen the possible signals, allowing only those that meet the requirement of honesty to stabilize. These include indices and added-cost signals. The emission of pheromones plays a variety of roles in the life processes of living beings. It facilitates encounters between individuals of the same species and is heavily involved in the mechanisms of recognition of relatives. It also fosters behaviours such as altruism (cooperation between individuals that share a percentage of their genetic inheritance). In many species, including humans, chemical communication works behind the scenes to guide the choice of a sexual partner
Neural tube closure: cellular, molecular and biomechanical mechanisms.
Neural tube closure has been studied for many decades, across a range of vertebrates, as a paradigm of embryonic morphogenesis. Neurulation is of particular interest in view of the severe congenital malformations - 'neural tube defects' - that result when closure fails. The process of neural tube closure is complex and involves cellular events such as convergent extension, apical constriction and interkinetic nuclear migration, as well as precise molecular control via the non-canonical Wnt/planar cell polarity pathway, Shh/BMP signalling, and the transcription factors Grhl2/3, Pax3, Cdx2 and Zic2. More recently, biomechanical inputs into neural tube morphogenesis have also been identified. Here, we review these cellular, molecular and biomechanical mechanisms involved in neural tube closure, based on studies of various vertebrate species, focusing on the most recent advances in the field
Transcatheter device closure of atrial septal defect and patent foramen ovale in Malta
Significant atrial septal defects (ASD) are closed, surgically or through a transcatheter device, in order to avoid pulmonary hypertension in late life. A patent foramen ovale (PFO) may need to be closed because of transient shunt reversal resulting in transient ischaemic events or stroke. We report the Maltese experience to date in transcatheter closure of these defects. A total of 46 ASDs and 51 PFOs have been successfully closed at our unit (total 97), with very low complication rates, rates that compare very favourably with results from larger international centres.peer-reviewe
Laterality Differences in Cerebellar-Motor Cortex Connectivity
Lateralization of function is an important organizational feature of the motor system. Each effector is predominantly controlled by the contralateral cerebral cortex and the ipsilateral cerebellum. Transcranial magnetic stimulation studies have revealed hemispheric differences in the stimulation strength required to evoke a muscle response from the primary motor cortex (M1), with the dominant hemisphere typically requiring less stimulation than the nondominant. The current study assessed whether the strength of the connection between the cerebellum and M1 (CB-M1), known to change in association with motor learning, have hemispheric differences and whether these differences have any behavioral correlate. We observed, in right-handed individuals, that the connection between the right cerebellum and left M1 is typically stronger than the contralateral network. Behaviorally, we detected no lateralized learning processes, though we did find a significant effect on the amplitude of reaching movements across hands. Furthermore, we observed that the strength of the CB-M1 connection is correlated with the amplitude variability of reaching movements, a measure of movement precision, where stronger connectivity was associated with better precision. These findings indicate that lateralization in the motor system is present beyond the primary motor cortex, and points to an association between cerebellar M1 connectivity and movement execution
- …