56 research outputs found
Association of Structural Magnetic Resonance Imaging Measures With Psychosis Onset in Individuals at Clinical High Risk for Developing Psychosis:An ENIGMA Working Group Mega-analysis
IMPORTANCE The ENIGMA clinical high risk (CHR) for psychosis initiative, the largest pooled neuroimaging sample of individuals at CHR to date, aims to discover robust neurobiological markers of psychosis risk.OBJECTIVE To investigate baseline structural neuroimaging differences between individuals at CHR and healthy controls as well as between participants at CHR who later developed a psychotic disorder (CHR-PS+) and those who did not (CHR-PS-).DESIGN, SETTING, AND PARTICIPANTS In this case-control study, baseline T1-weighted magnetic resonance imaging (MRI) data were pooled from 31 international sites participating in the ENIGMA Clinical High Risk for Psychosis Working Group. CHR status was assessed using the Comprehensive Assessment of At-Risk Mental States or Structured Interview for Prodromal Syndromes. MRI scans were processed using harmonized protocols and analyzed within a mega-analysis and meta-analysis framework from January to October 2020.MAIN OUTCOMES AND MEASURES Measures of regional cortical thickness (CT), surface area, and subcortical volumes were extracted from T1-weighted MRI scans. Independent variables were group (CHR group vs control group) and conversion status (CHR-PS+ group vs CHR-PS- group vs control group).RESULTS Of the 3169 included participants, 1428 (45.1%) were female, and the mean (SD; range) age was 21.1 (4.9; 9.5-39.9) years. This study included 1792 individuals at CHR and 1377 healthy controls. Using longitudinal clinical information, 253 in the CHR-PS+ group, 1234 in the CHR-PS- group, and 305 at CHR without follow-up data were identified. Compared with healthy controls, individuals at CHR exhibited widespread lower CT measures (mean [range] Cohen d = -0.13 [-0.17 to -0.09]), but not surface area or subcortical volume. Lower CT measures in the fusiform, superior temporal, and paracentral regions were associated with psychosis conversion (mean Cohen d = -0.22; 95% CI, -0.35 to 0.10). Among healthy controls, compared with those in the CHR-PS+ group, age showed a stronger negative association with left fusiform CT measures (F = 9.8; P < .001; q < .001) and left paracentral CT measures (F = 5.9; P = .005; q = .02). Effect sizes representing lower CT associated with psychosis conversion resembled patterns of CT differences observed in ENIGMA studies of schizophrenia (rho = 0.35; 95% CI, 0.12 to 0.55; P = .004) and individuals with 22q11.2 microdeletion syndrome and a psychotic disorder diagnosis (rho = 0.43; 95% CI, 0.20 to 0.61; P = .001).CONCLUSIONS AND RELEVANCE This study provides evidence for widespread subtle, lower CT measures in individuals at CHR. The pattern of CT measure differences in those in the CHR-PS+ group was similar to those reported in other large-scale investigations of psychosis. Additionally, a subset of these regions displayed abnormal age associations. Widespread disruptions in CT coupled with abnormal age associations in those at CHR may point to disruptions in postnatal brain developmental processes.Question How are brain morphometric features associated with later psychosis conversion in individuals at clinical high risk (CHR) for developing psychosis?Findings In this case-control study including 3169 participants, lower cortical thickness, but not cortical surface area or subcortical volume, was more pronounced in individuals at CHR in a manner highly consistent with thinner cortex in individuals with established psychosis. Regions that displayed lower cortical thickness in individuals at CHR who later developed a psychotic disorder additionally displayed abnormal associations with age.Meaning In this study, CHR status and later transition to psychosis was robustly associated with lower cortical thickness; abnormal age associations and specificity to cortical thickness may point to aberrant postnatal brain development in individuals at CHR, including pruning and myelination.This case-control study investigates baseline structural magnetic resonance imaging (MRI) differences between individuals at clinical high risk and healthy controls as well as between participants at clinical high risk who later developed a psychotic disorder and those who did not
Lichenometric dating (lichenometry) and the biology of the lichen genus rhizocarpon:challenges and future directions
Lichenometric dating (lichenometry) involves the use of lichen measurements to estimate the age of exposure of various substrata. Because of low radial growth rates and considerable longevity, species of the crustose lichen genus Rhizocarpon have been the most useful in lichenometry. The primary assumption of lichenometry is that colonization, growth and mortality of Rhizocarpon are similar on surfaces of known and unknown age so that the largest thalli present on the respective faces are of comparable age. This review describes the current state of knowledge regarding the biology of Rhizocarpon and considers two main questions: (1) to what extent does existing knowledge support this assumption; and (2) what further biological observations would be useful both to test its validity and to improve the accuracy of lichenometric dates? A review of the Rhizocarpon literature identified gaps in knowledge regarding early development, the growth rate/size curve, mortality, regeneration, competitive effects, colonization, and succession on rock surfaces. The data suggest that these processes may not be comparable on different rock surfaces, especially in regions where growth rates and thallus turnover are high. In addition, several variables could differ between rock surfaces and influence maximum thallus size, including rate and timing of colonization, radial growth rates, environmental differences, thallus fusion, allelopathy, thallus mortality, colonization and competition. Comparative measurements of these variables on surfaces of known and unknown age may help to determine whether the basic assumptions of lichenometry are valid. Ultimately, it may be possible to take these differences into account when interpreting estimated dates
Perda de nitrogĂȘnio pela Brachiaria decumbens apĂłs a antese: relação com a umidade do solo
Clinical characteristics of women captured by extending the definition of severe postpartum haemorrhage with 'refractoriness to treatment': a cohort study
Background: The absence of a uniform and clinically relevant definition of severe postpartum haemorrhage
hampers comparative studies and optimization of clinical management. The concept of persistent postpartum
haemorrhage, based on refractoriness to initial first-line treatment, was proposed as an alternative to common
definitions that are either based on estimations of blood loss or transfused units of packed red blood cells
(RBC). We compared characteristics and outcomes of women with severe postpartum haemorrhage captured
by these three types of definitions.
Methods: In this large retrospective cohort study in 61 hospitals in the Netherlands we included 1391 consecutive
women with postpartum haemorrhage who received either â„4 units of RBC or a multicomponent transfusion. Clinical
characteristics and outcomes of women with severe postpartum haemorrhage defined as persistent postpartum
haemorrhage were compared to definitions based on estimated blood loss or transfused units of RBC within 24 h
following birth. Adverse maternal outcome was a composite of maternal mortality, hysterectomy, arterial embolisation
and intensive care unit admission.
Results: One thousand two hundred sixty out of 1391 women (90.6%) with postpartum haemorrhage fulfilled the
definition of persistent postpartum haemorrhage. The majority, 820/1260 (65.1%), fulfilled this definition within 1 h
following birth, compared to 819/1391 (58.7%) applying the definition of â„1 L blood loss and 37/845 (4.4%) applying
the definition of â„4 units of RBC. The definition persistent postpartum haemorrhage captured 430/471 adverse maternal
outcomes (91.3%), compared to 471/471 (100%) for â„1 L blood loss and 383/471 (81.3%) for â„4 units of RBC. Persistent
postpartum haemorrhage did not capture all adverse outcomes because of missing data on timing of initial, first-line
treatment.
Conclusion: The definition persistent postpartum haemo
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and lowâmiddle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of âsingle-useâ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for lowâmiddle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both highâ and lowâmiddleâincome countries
Geochemical mapping of the rural and urban environment : an aid for the detection of contaminated land
The cost-effective reclamation of contaminated land and/or water resources requires a detailed knowledge
of the current state of contamination and an understanding of the natural background to which the site may
be most appropriately returned. Within this context, the British Geological Survey is in the process of
completing a systematic national geochemical survey of the UK surface environment based on the
collection of stream sediments, soils and stream waters to produce a series of geochemical maps which can
be integrated with other environmental information to produce valuable baseline and benchmark data for
both rural and urban environments
Wolverhampton urban environmental survey : an integrated geoscientific case study
Geoscience and land use information for the Metropolitan Borough of Wolverhampton have been collated,
with the assistance of the Metropolitan Authority, and interpreted with the aid of a Geographical
Information System (GIS). The digital data can be rapidly manipulated within the GIS to produce
customised thematic maps of the urban area.
The report is a summary of a study undertaken in the Borough over a period of three years, and is supported
by a number of satellite reports which describe in more detail different aspects of the work.
The Borough of Wolverhampton lies on the western edge of the South Staffordshire Coalfield. The Western
Boundary Fault bisects the Borough and marks the edge of the exposed coalfield. To the west of this
structure the Coal Measures are concealed by a thick sequence of Upper Carboniferous and Permo-Triassic
redbeds. Glacial deposits, mainly clay-rich till with subordinate sands, gravels and laminated clays, cover
much of the area. The till is of variable thickness but due to its impermeability it affords some protection
to the migration of potential contaminants. Spoil and waste (made ground) from former coal workings cover
much of the eastern part of the Borough which is also extensively undermined. Thematic maps indicating
the extent and depth of the made ground, depth of till, extent of undermining and location of landfill sites
provide useful planning information
The geochemical estimation of solute residence times in some reference hydrogeological settings
This report assesses the concept of 'solute residence time' and considers whether the definition of
'reference' hydrogeological environments (RHEs) can be used to aid the geochemical estimation of
solute residence times in groundwaters.
In general, previous studies of techniques for estimating groundwater 'ages' have emphasised
determinations of the times since groundwaters were recharged. However, there have been
relatively few assessments of the time for which solutes have been resident in the aqueous phase
within a particular 'rock reservoir' (defined as a volume of rock, including all the matrix and
fracture porosity which occurs within it). Such assessments need to be made during investigations
of potential deep sites for the geological disposal of radioactive wastes.
For groundwaters, solute residence times are normally defined for steady state conditions as
follows (Stumm and Morgan, 1981):
'tE = [ElV
[E]inq
where [E] and [Elin are the total concentration of solute in the system and the inflow respectively,
V is the total volume of the groundwater, and q is the rate of groundwater infiltration. The
'residence time' in this case is simply the time that is required for the quantity of a solute that is
present in the system at any instant, to be replaced completely by a fresh quantity of that solute.
However, operational difficulties arise when this definition is applied to solutes in groundwater
systems. This is because compositional gradients commonly arise along a groundwater flow path
(even when such a system is at steady state), and also because samples are typically taken from·
point sources. Therefore, the total quantity of a solute that is present in a reservoir of interest is
difficult to assess and a range of residence times will be estimated from waters sampled in different
places along a groundwater flow-path. A more appropriate definition of solute residence time is the
maximum estimated time for which a solute has been present within a rock reservoir of interest (or
alternatively, the minimum time that would be taken to flush all the solute of a given type from the
reservoir of interest).
There are three main types of technique that can be used in solute residence time studies:
1. Techniques that, under ideal circumstances, may. yield quantitative residence time
estimations;
2. Techniques that, under ideal circumstances, may yield quantitative, but limiting (maximum
or minimum) residence time estimates;
3. Techniques that, under ideal circumstances, may yield only relative residence time
indications.
The actual type of residence time estimate that may be made using a particular technique will
depend partly upon the hydrogeological setting of the rock reservoir of interest. A particular
technique that may yield quantitative residence time estimates under some circumstances, may yield
only limiting residence time estimates under others.
If non-steady state conditions prevail, then the estimation of residence times for solutes in any rock
reservoir becomes much more difficult or even impossible. In general, techniques that are
potentially quantitative under steady state conditions will give only limiting residence times under
non-steady state conditions. Techniques that may yield limiting or relative residence times under
steady state conditions will also tend to yield limiting or relative residence times under non-steady
state conditions.
Any hydrogeological environment can be considered to contain a number of different groundwater
reservoirs (e.g. rock matrix, faults, an aquifer, an aquiclude, etc.), and a given solute will have a
different residence time within each reservoir. Additionally, the 'ages' that are obtained may be an
integration of the residence times of the water and/or solutes within a series of reservoirs, if the
boundaries of the reservoirs are poorly defined. A set of rules is proposed for evaluating what type
of residence time indication (quantitative, limiting or relative) might be obtained from a particular
technique in any rock reservoir of interest. These rules are then applied to different rock reservoirs
within each of seven different reference geological environments. These environments were chosen
in order to represent a spectrum of hydrogeological environments within which potential
radioactive waste repositories might be constructed:
1 . Crystalline Shield Type
2. Argillaceous Rock Beneath Low-lying Plain Type
3. Coastal, Basin Margin Type
4. Salt Dome Beneath Low-lying Plain Type
5. Basin and Range Type
6. Argillaceous Rock in Foreland Basin Type
7. Sedimentary Basin at a Destructive Plate Margin Type
For each environment a table is presented which indicates what type of information might be
obtained from each of the major techniques for estimating solute residence times. The aim is to present a tool which might be used to design strategies for evaluating residence times of solutes in
groundwaters.
It is possible to use such reference environments in order to establish priorities for the application
of techniques. However, it is nec:essary for these techniques to be applied in conjunction with
groundwater head data and geochemical data for the origins of the waters and their salinities. Such
data enable the boundary conditions of rock reservoirs to be defined, and the flow paths of
groundwaters to be constrained. A knowledge of groundwater flow paths is essential in order to
make a thorough assessment of the applicability of a technique for groundwater dating
Parent-Infant Cosleeping: fathers' roles and perspectives
Dyadic co-sleeping (mother-baby) is a common strategy for night-time infant care in the majority of world cultures. Triadic co-sleeping (mother-father-baby) is less common, although still widely practised cross-culturally. This paper examines triadic co-sleeping in an opportunistic sample of parents from the North Tees region of England, and explores fathers' expectations and experiences of sleeping with their babies. Using a prospective study design, 36 sets of parents, pre- and post-natally, were interviewed about infant care strategies, particularly at night. Although they did not anticipate sleeping with their infants at the pre-natal interview, the majority of fathers (81%) had done so by the time of the second interview. First-time fathers were afraid that they would squash or suffocate the baby in their sleep, and some were concerned that the infant's presence would adversely affect their own sleep. Fathers used a variety of strategies to help overcome their initial fears of co-sleeping. Among those for whom triadic co-sleeping became a regular night-time infant care strategy, the pleasures of prolonged intimate contact with their infant were clearly apparent. It is suggested that the experience of sleeping with their infant ameliorates some of the distancing effects felt by fathers outside the breast-feeding relationship, and helps encourage paternal involvement in night-time infant care-giving
- âŠ