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Magnesian Limestone zoned dolomite (red and non-luminescent zones) now partly dedolomitized), calcite (yellow luminescence), blue luminescent albite has non-luminescent overgrowths) Mansfield Quarry, Nottinghamshire. Modern tropical carbonate sediments are generally aragonite and high-Mg calcite with high porosities (Enos & Swatsky, [16]), yet ancient carbonates (Miocene and older) are generally calcite or dolomite with far lower porosity. Dissolution of aragonite and Mg calcite with precipitation of calcite cements with 2-8 mol% MgCO SB 3 sb occur in sea water undersaturated with respect to aragonite and high-Mg calcite, but supersaturated with respect to low-Mg calcite. The Xiong et al. compilation shows that the cycles of aragonite/high-Mg calcite were more variable than previously recognised, with the first inferred transition from a high-Mg calcite to low-Mg calcite sea occurring during early Cambrian stage 3. [Extracted from the article]

The dynamic inter‐relationships between marine and freshwater carbonate depositional environments are illustrated in the Sian Ka'an Wetlands, a 5 280 km2 complex of groundwater‐fed freshwater marshes, lakes and brackish coastal lagoons in the South‐East Yucatán Peninsula (Mexico). The Yucatán Platform was subaerially emergent and extensively karstified during the last glacial maximum at 18, 000 yr bp. The Late Holocene transgression has caused progressive reflooding of the continental margin, backstepping of the MesoAmerican Reef and encroachment of coastal environments into the platform interior as rising groundwaters flood an interconnected cave and sinkhole system and feed seasonal marshes above. The Sian Ka'an Wetlands form a vast palustrine carbonate factory which is directly juxtaposed and dynamically linked with the marine carbonate factory to seaward. Continuing sea‐level rise has caused synchronous landward migration of marginal marine and freshwater environments as beach barriers were breached and palustrine sloughs flooded to form marginal marine seagrass lagoons. The Rio Hondo Fault conditions fluid inflow while the sub‐environments of the Sian Ka'an Wetlands reflect tectonic controls on microtopography and hydroperiod. Modern analogues for the Sian Ka'an Wetlands include the Florida Everglades, formed during transgression of the Florida Platform, and relict marsh environments preserved on leeward shores of Andros, Abaco and other Bahama islands. A wide range of ancient examples deposited in coastal and continental interior settings similarly reflect seasonal aquifer rise in response to marine transgression and/or onlap of late‐stage basin fill onto a karstified pediment. Freshwater palustrine carbonate factories on carbonate platforms are transient deposystems, controlled by subtle water depth, climate, vegetation and hydrological factors while being critically sensitive to sea‐level changes and tectonics. The preservation potential of palustrine carbonates may be relatively low in coastal settings due to erosion or shallow marine overprinting, while greater further inland where marine flooding is rarer and in tectonically subsident continental interior basins where accommodation space is continuously created. [ABSTRACT FROM AUTHOR]

Side‐scan sonar and Compressed High Intensity Radar Pulse mapping of Great Salt Lake, Utah, linked to reprocessing of acoustic data from bathymetric surveys, has enabled the distribution of microbial bioherms to be assessed. Bioherms occupy an estimated area >700 km2 in the south arm and >300 km2 in the north arm. Distributions vary from statistically dispersed to clustered, and in this latter case, are predominantly located on metre‐scale, fault‐controlled topographic highs, with sediment infilling intervening lows between adjacent offsets. Individual bioherms are circular to oblate and range from centimetres to over 2 m in diameter. In some areas, bioherm heights were measured at more than 1.5 m above adjacent substrate. Sublittoral bioherms are made of aragonite, calcite and minor dolomite precipitated due to physico‐chemical, biologically induced and influenced carbonate mineralization processes in association with microbial mats. Bioherm fabrics vary at the millimetre to centimetre‐scale and consist of leiolitic and clotted peloidal micrite‐grade carbonate, sinuous threads of spherulitic fibrous aragonite crystals, laminated micrite boundstone and internal carbonate mud sediment with peloids and ooids. The identification of factors that influence microbial bioherm occurrence and spatial distribution in Great Salt Lake is limited to a set of collinear physical, chemical and biological variables that are confined to a localised closed system, such as salinity, water depth, wave energy, stable substrate and sediment accumulation. Anthropogenic modifications to Great Salt Lake resulting in increased salinity have exceeded the salinity range in which bioherm‐mediating microbial communities can survive, effectively defining an upper limit of salinity for bioherm microbial community viability. The better understanding of the distribution of microbial bioherms has significant implications for managing and protecting the lake ecosystem and may provide insights into the physical and chemical controls that existed during the formation of fossil microbialites in deep time. [ABSTRACT FROM AUTHOR]

During the Aptian (Cretaceous), in what is now the South Atlantic, the largest chemogenic (abiotic) carbonate factory so far identified in the Phanerozoic geological record developed as a vast hyper‐alkaline lake system. This covered at least 330 000 km2, producing carbonates, locally over 500 m thick, in what are now the offshore Santos and Campos basins (Brazil), and Kwanza Basin (Angola). Current evidence supports the view that almost all of this carbonate was chemogenic in origin, precipitated from hyper‐alkaline, shallow lake waters, probably by evaporation. This unit, best documented from offshore Brazil and known as the Barra Velha Formation (Santos Basin) and the Macabu Formation (Campos Basin), consists of just two basic carbonate components, millimetre to centimetre sized crystal shrubs and spherulites. These are commonly in situ but can also be reworked into a range of detrital facies. Demonstrable microbialites are generally rare. These carbonates are associated with Mg silicates (as clays) which had a profound influence not only on the textural development of the in situ carbonates, but also on their diagenesis. The dissolution of the clays produced much of the porosity in these limestones, which are the hosts for multi‐billion barrel oil fields. The source of the carbonate was most likely from metasomatic alteration of mafic rocks, such as continental flood basalts related to Atlantic opening, with some contribution from much older continental basement. Clear evidence that serpentinization of possible exhumed mantle is lacking but mantle CO2 is likely to have been a critical factor in determining the composition of the fluids from which the carbonates formed and the high alkalinities of the lake waters. [ABSTRACT FROM AUTHOR]

The Aptian lacustrine carbonates of the Barra Velha Formation, offshore Brazil, have undergone a highly unusual paragenetic and diagenetic history and present significant terminological problems if current textural classifications are applied. Existing limestone classifications invoke the concept of textural maturity, whereby the ratio of matrix to grain is a critical property and can be used to infer energy levels and the degree of transport prior to deposition. In the Barra Velha Formation, some critical carbonate grains grew in a matrix which later dissolved, congruently, producing what appears to be primary intergranular porosity. In addition, apparent boundstone textures occur, not due to organic trapping or binding, but ones which can be shown to be diagenetic, and were also related in part to the former presence of labile matrices. Thus, applying some terms in existing classifications can lead to false interpretations, and to avoid misinterpretations criteria for identifying ghost (former) matrices are provided. [ABSTRACT FROM AUTHOR]

The sedimentology, petrography and mineralogy of the seemingly monotonous Late Triassic Mercia Mudstone Group across the Severn Basin and Bristol Channel region reveals a bipartite division of mudrock facies above and below the Arden Sandstone Formation. Frequently cryptic sedimentary and pedogenic features reveal diverse alluvial, aeolian, playa‐lacustrine and pedogenic processes operating at different times, locations and scales probably in response to climate change. The current study found no evidence of significant marine influence in either of the two mudrock facies associations that are described here. Blocky claystones dominate the lower Mercia Mudstone Group (Sidmouth Mudstone Formation), with pedogenic features such as slickensides, mottling, tubules and carbonate/sulphate nodules common and widespread. The claystones are of alluvial/lacustrine origin with subordinate sheet sandstones, themselves overprinted by pedogenic features, reflecting occasional high intensity rainfall events. These facies reflect a seasonal (wet/dry) semi‐arid climate favouring development of transformed/neoformed (smectite‐rich) clay minerals of intrabasinal origin. Massive to weakly stratified silty mudstones dominate the upper Mercia Mudstone Group (Branscombe Mudstone Formation). Commonly conchoidally weathered, locally gypsiferous, but with distinct sedimentary structures scarce, they alternate with subordinate blue‐grey laminated silty mudstones. Together they reflect fluctuating hydrological conditions within extensive saline mudflats and ephemeral playa lakes, with laminated facies deposited under subaqueous conditions during more humid phases whereas massive mudstones reflect modification through interstitial growth/dissolution of sulphates and deflation of surface sediments during drier episodes. These facies reflect increased aridity during deposition of the upper Mercia Mudstone Group compared with the lower Mercia Mudstone Group, favouring development of detrital/transformed (illite–chlorite) clay minerals of extrabasinal origin. The described facies associations and the sedimentary fabrics and structures that characterize them, occur widely in the Mercia Mudstone Group across the United Kingdom and comparable facies associations may be anticipated in other fine‐grained red bed successions. Recognition of these facies may aid palaeoenvironmental interpretation of such sequences on Earth and, potentially, on Mars also. [ABSTRACT FROM AUTHOR]

The paper reports on collaborative journal writing and dialogue sustained by two education professionals with a view to engaging in meaningful reflective practice. The transition from journal writing to reporting in this paper was underpinned by knowledge of the place of reflective practice in teacher education and continuous professional development. Knowledge of the limited opportunities and time for meaningful continuous professional development, as experienced across the education sector, also informed a desire to share the writing experience with a view to encouraging other teachers to develop writing communities. As teacher educators, we relate how we came to write together and sustained a dialogue that provided us with newly framed insights into our professional lives and experiences. Our journalling told our stories and was very much in the spirit of evocative autoethnography. We describe how we naturally included sensory description related to the time and place of writing. We also used more evocative language, including the use of metaphors. Themes of critical reflection, reflexivity, embodied reflection and evocative autoethnography are therefore explored in the light of our writing experience. The journals and the associated dialogue highlight the values of such small and time constrained moments as informal professional development opportunities. [ABSTRACT FROM AUTHOR]

Retail beef markets not offering objective grade indicators in-store leave consumers uncertain about the quality of beef they purchase. The introduction of fresh brands can better meet consumers’ expectations. Willingness-to-pay for ‘ideal’ quality cuts represents the maximum premiums brands could achieve. Using Australian consumers’ survey data, the maximum premiums are modelled using zero-inflated negative binomial models. Results indicate that buyer’s characteristics and perceptions about product attributes influence the premiums for high-quality beef that consumers are willing to pay for a cut considered ‘ideal’, indicating the maximum premium that brands could achieve in relevant segments. The premiums indicate there is substantial potential for beef cuts that reduce purchase risk by more assuredly meeting buyer’s preferences in Australia. [ABSTRACT FROM AUTHOR]

The most salient feature of conservation today is contradiction. Conservation is simultaneously characterized by decentralisation and recentralisation, deterritorialisation and reterritorialisation, deregulation and reregulation. At the heart of these contradictions are reconfigurations of state-society relations, provoking unprecedented risk but also opportunity for rural communities. Paramount to these processes is the threat of 'recentralizing while decentralizing' (Ribot et al. 2006). Governments decentralise authority while simultaneously finding ways to retain central control and maintain their political and/or economic interests. Recentralising while decentralising especially defines Tanzania's most recent decentralisation scheme, Wildlife Management Areas (WMAs). This paper contributes to the debate about WMAs and the nature of decentralisation. The WMAs, I argue, represent risk but also opportunity for rural communities. Amidst the contradictions and conundrum of decentralising and recentralising, new political spaces invariably emerge, wherein novel alliances, political community, and resistance unfold. In cases like Enduimet and Lake Natron WMAs, this has translated into appropriating and redeploying WMAs in ways that privilege community interests. Notwithstanding the significant constraints that continue jeopardizing most WMAs, the cases reviewed in this paper offer some hope for WMAs' turbulent terrains. [ABSTRACT FROM AUTHOR]

Latest Precambrian to Early Palaeozoic biosphere evolution triggered changes in early diagenesis and carbonate precipitation which fed back to biodiversity through colonization of hard substrates. Progressive increase in the depth and intensity of bioturbation and bio-irrigation lowered the zone of early carbonate cementation in the uppermost sediment column. This firstly led to a decline in the abundance of the flat-pebble conglomerates which had been a common feature of Cambrian and Early Ordovician successions, replaced by the peak and subsequent decline in the Palaeozoic abundance of submarine hardgrounds. The availability of very widespread lithified sea floors in shallow subtidal settings during the Ordovician promoted a rapid expansion in sclerobiont diversity and contributed to the Great Ordovician Biodiversification Event. [ABSTRACT FROM AUTHOR]

This paper discusses the turbulent times facing trophy hunting in Tanzania, East Africa. It reviews the industry’s contentious history, and illustrates the ominous politics that are emerging out of the country’s recent neoliberal schemes, Wildlife Management Areas. Through the decentralisation that comprises WMAs, the rural communities who co-inhabit trophy hunting spaces are finding new ways to limit, resist, and sometimes, eliminate it. As argued in this paper, trophy hunting in Tanzania faces a momentous convergence of aggrieved histories, and neoliberal reforms that shift authority to rural communities. It amounts to turbulent times and what I call, fighting history today. [ABSTRACT FROM AUTHOR]

Objective The Child and Adolescent Scale of Participation ( CASP) parent report is a brief and valid measure for use with children and youth with chronic conditions/disabilities that has been shown to have good coverage at the chapter level of the ' Activities and Participation' component of the International Classification of Functioning, Disability and Health. The purpose of this research was to assess the psychometric properties of a CASP youth self-report version, to further validate the parent report, and to compare parent and youth reports of youths' activity and participation. Methods Baseline data from a longitudinal study examining predictors of changes in quality of life for youth with chronic conditions/disabilities were used. CASP data were collected on 409 youth aged 11-17 with various conditions/disabilities using youth and parent reports. Internal consistency and factor structure were examined for both versions using Cronbach's alpha and exploratory factor analyses. Inter-rater agreement and magnitude of differences between youth and parent report were evaluated using intraclass correlation coefficients and paired t-tests respectively. Gender, age and condition/disability group differences in youth report CASP scores were examined using independent t-tests or analyses of variance. Results Strong internal consistency and internal structure validity was demonstrated for the CASP youth and parent report. The youth report factor structure was similar to the parent report in this and other studies. Youth reported their activity/participation to be significantly higher than did their parents. Significant differences in CASP scores were found among condition/disability groups. Conclusions Findings show that, from a psychometric standpoint, the youth version of the CASP is a promising new self-report measure of activity and participation. As youth perceive their activity and participation levels differently than their parents, it is important to collect data from both sources to obtain a more comprehensive understanding of this aspect of youths' lives. [ABSTRACT FROM AUTHOR]

The benefits and drawbacks of facilitating independent walking in children with physical mobility impairments, such as cerebral palsy, remain to be determined. This knowledge gap creates decision dilemmas about which mobility practices parents and children should adopt and rehabilitation professionals should foster. These dilemmas are reflected in continuing debates about allocation of time, effort and resources to optimize walking versus encouraging use of manual or powered wheelchairs. Recent studies have reported only modest measurable walking progress for severely disabled children using hands-free walkers. Despite these seemingly disappointing results, parents remained highly motivated to encourage their children to use these walking devices and appraised them very positively. In the present paper, we suggest that parents’ symbolic value of their children assuming upright comportment may explain why they perceive hands-free walkers positively and why they are so motivated to devote much time and effort to improving independent, walking-based mobility of their children. [ABSTRACT FROM AUTHOR]

The benefits and drawbacks of facilitating independent walking in children with physical mobility impairments, such as cerebral palsy, remain to be determined. This knowledge gap creates decision dilemmas about which mobility practices parents and children should adopt and rehabilitation professionals should foster. These dilemmas are reflected in continuing debates about allocation of time, effort and resources to optimize walking versus encouraging use of manual or powered wheelchairs. Recent studies have reported only modest measurable walking progress for severely disabled children using hands-free walkers. Despite these seemingly disappointing results, parents remained highly motivated to encourage their children to use these walking devices and appraised them very positively. In the present paper, we suggest that parents’ symbolic value of their children assuming upright comportment may explain why they perceive hands-free walkers positively and why they are so motivated to devote much time and effort to improving independent, walking-based mobility of their children. [ABSTRACT FROM PUBLISHER]

Cyberbullying is a growing concern because youth are technologically savvy. Much is to be learned about this pervasive phenomenon, especially during the middle school years when cyberbullying often peaks. This focus group study examined cyberbullying attitudes, beliefs, and opinions among middle school students in Alabama and describes conversations middle school students shared in the interviews. [ABSTRACT FROM AUTHOR]

Background Walking for children with cerebral palsy (CP) has physiological and functional benefits, but also holds symbolic significance that largely remains unexplored. The aims of this pilot study were to describe beliefs about the value of walking held by children with CP and their parents, and to examine how these beliefs inform rehabilitation choices and perceptions of 'success'. Methods A critical qualitative design was employed. Six parents and six children with CP (Gross Motor Function Classification System III or IV, aged 9 to 18 years) each participated in a private interview. Analyses examined the relationship between dominant social beliefs regarding walking and participants' accounts. Results Parents' accounts revealed that all adopted a stance of doing something/trying anything as part of being a 'good parent' and maintaining hope. Tapering of walking interventions contributed to feelings of guilt and doubt. Children primarily viewed walking as exercise rather than functional. Their accounts also demonstrated how they internalized negative attitudes towards disability and judged themselves accordingly. Conclusions The results of this pilot study provide provisional evidence regarding how dominant social values regarding walking and disability are taken up by parents and children. They suggest that rehabilitation programmes need to consider how they may unintentionally reinforce potentially harmful choices, and how best to engage families in discussions of their evolving values and treatment priorities. Further research is needed with a larger sample. [ABSTRACT FROM AUTHOR]