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The release of phosphorus (P) from crustal rocks during weathering plays a key role in determining the size of Earth’s biosphere, yet the concentration of P in crustal rocks over time remains controversial. Here, we combine spatial, temporal, and chemical measurements of preserved rocks to reconstruct the lithological and chemical evolution of Earth’s continental crust. We identify a threefold increase in average crustal P concentrations across the Neoproterozoic-Phanerozoic boundary (600 to 400 million years), showing that preferential biomass burial on shelves acted to progressively concentrate P within continental crust. Rapid compositional change was made possible by massive removal of ancient P-poor rock and deposition of young P-rich sediment during an episode of enhanced global erosion. Subsequent weathering of newly P-rich crust led to increased riverine P fluxes to the ocean. Our results suggest that global erosion coupled to sedimentary P-enrichment forged a markedly nutrient-rich crust at the dawn of the Phanerozoic.

New first-year students are vulnerable to dropping out of university because the transition into higher education (HE) is difficult to navigate. Using thematic analysis, we analysed focus groups/interview, exit interviews and qualitative survey data with university students during their first year as criminology undergraduates to explore how they transitioned into HE. Findings show that the transition to a new identity of ‘university student’ was hampered by feelings of awkwardness, which prevented students from fully integrating into student life. However, the subject of criminology was a protective factor because interest in the topic and wanting a degree for betterment, including for future career plans, buffered students against dropping out. We argue that subject specific interventions may be better in supporting the retention of students and that addressing physical, social and academic awkwardness is key.

The expressive power of natural languages depends on their regular compositional structure, which allows us to express and understand an infinite set of messages. However, a complete model of language evolution should also account for irregular exceptions to regular rules, common in natural languages. Historical linguistics has established a correlation between irregularity and frequency in language use, which has been attributed to preferential irregularisation of frequent items, or preferential regularisation of infrequent items. In an iterated learning experiment where participants learn and reproduce a miniature language across multiple generations, we show that this correlation can be explained by the relationship between frequency, regularity and learnability, without needing to appeal to frequency-dependent irregularisation. We find that systems of plural marking regularise across generations of transmission, but that high-frequency items remain irregular. Our results further show that the persistence of irregularity is due to high frequency overriding pressures which normally reduce learnability, such as low generalisability of the inflectional strategy (suppletion is disfavoured except in high frequency items) and low type frequency (belonging to a small inflectional class is disfavoured except in high frequency items).

In one of the most common procedures for studying recognition memory, subjects first study a set of items with instructions to remember them for a subsequent memory test and later are shown randomly intermixed studied and non-studied items one at a time and asked to make old/new recognition judgment for each one. We refer to this as the study-test or ST procedure. In a different approach, items are presented one at a time for old/new recognition judgments, with some items being re-presented after varying lags. This is called the continuous recognition, or CR procedure. We speculated that there may be interesting psychological differences between ST and CR, as intuitively the task demands of the two procedures seem to us quite different.

In one of the most common procedures for studying recognition memory, subjects first study a set of items with instructions to remember them for a subsequent memory test and later are shown randomly intermixed studied and non-studied items one at a time and asked to make old/new recognition judgment for each one. We refer to this as the study-test or ST procedure. In a different approach, items are presented one at a time for old/new recognition judgments, with some items being re-presented after varying lags. This is called the continuous recognition, or CR procedure. We speculated that there may be interesting psychological differences between ST and CR, as intuitively the task demands of the two procedures seem to us quite different. In an ST procedure, during the study phase participants do something to encode items, and then they are distracted by some other activity for a while, and then they make recognition judgments about test probes. The participant’s goals and orientation during study and test phases of ST are quite different and they are temporally separated. In contrast, in CR each item (after the first item) is to be processed both as a to-be-remembered stimulus and as a test probe, such that studying and testing are intermingled. Participants typically don’t know how many or few items will intervene between the initial presentation of a stimulus and its representation, and that might encourage them to try to keep more stimuli in mind for a longer period. At the start of this research we did not have specific predictions but we thought that task-demand differences between ST and CR might produce differences in hit or FA rates and/or differences in subjective reports such as confidence ratings and Remember/Know judgments. We also intend to examine response latency for recognition decisions. We have already completed 6 experiments comparing ST and CR and have observed that, for word stimuli, we get more false alarms (FAs), but fewer hits, in CR vs. ST procedures, but for face stimuli we get more FAs and more hits in CR vs. ST. This experiment uses non-word stimuli.

In one of the most common procedures for studying recognition memory, subjects first study a set of items with instructions to remember them for a subsequent memory test and later are shown randomly intermixed studied and non-studied items one at a time and asked to make old/new recognition judgment for each one. We refer to this as the study-test or ST procedure. In a different approach, items are presented one at a time for old/new recognition judgments, with some items being re-presented after varying lags. This is called the continuous recognition, or CR procedure. We speculated that there may be interesting psychological differences between ST and CR, as intuitively the task demands of the two procedures seem to us quite different. In an ST procedure, during the study phase participants do something to encode items, and then they are distracted by some other activity for a while, and then they make recognition judgments about test probes. The participant’s goals and orientation during study and test phases of ST are quite different and they are temporally separated. In contrast, in CR each item (after the first item) is to be processed both as a to-be-remembered stimulus and as a test probe, such that studying and testing are intermingled. Participants typically don’t know how many or few items will intervene between the initial presentation of a stimulus and its representation, and that might encourage them to try to keep more stimuli in mind for a longer period. At the start of this research we did not have specific predictions but we thought that task-demand differences between ST and CR might produce differences in hit or FA rates and/or differences in subjective reports such as confidence ratings and Remember/Know judgments. We also intend to examine response latency for recognition decisions. We have already completed 6 experiments comparing ST and CR and have observed that, for word stimuli, we get more false alarms (FAs), but fewer hits, in CR vs. ST procedures. This experiment uses low-frequency word stimuli as target items, and their synonyms as matched lure items.

Supplemental data and materials associated with paper: Williams, H.L. and Lindsay, D.S. (2019). Different definitions of the nonrecollection-based response option(s) change how people use the “remember” response in the remember/know paradigm. Memory and Cognition. https://doi.org/10.3758/s13421-019-00938-0

In one of the most common procedures for studying recognition memory, subjects first study a set of items with instructions to remember them for a subsequent memory test and later are shown randomly intermixed studied and non-studied items one at a time and asked to make old/new recognition judgment for each one. We refer to this as the study-test or ST procedure. In a different approach, items are presented one at a time for old/new recognition judgments, with some items being re-presented after varying lags. This is called the continuous recognition, or CR procedure. We speculated that there may be interesting psychological differences between ST and CR, as intuitively the task demands of the two procedures seem to us quite different. In an ST procedure, during the study phase participants do something to encode items, and then they are distracted by some other activity for a while, and then they make recognition judgments about test probes. The participant’s goals and orientation during study and test phases of ST are quite different and they are temporally separated. In contrast, in CR each item (after the first item) is to be processed both as a to-be-remembered stimulus and as a test probe, such that studying and testing are intermingled. Participants typically don’t know how many or few items will intervene between the initial presentation of a stimulus and its representation, and that might encourage them to try to keep more stimuli in mind for a longer period. At the start of this research we did not have specific predictions but we thought that task-demand differences between ST and CR might produce differences in hit or FA rates and/or differences in subjective reports such as confidence ratings and Remember/Know judgments. We also intend to examine response latency for recognition decisions. We have already completed 6 experiments comparing ST and CR and have observed that, for word stimuli, we get more false alarms (FAs), but fewer hits, in CR vs. ST procedures, but for face stimuli we get more FAs and more hits in CR vs. ST. This experiment uses non-word stimuli which are shown in either a plain font or a distinctive font (e.g., varied on colour, size, font, and capitalization) at 1st presentation and shown in the other format at 2nd presentation.

In one of the most common procedures for studying recognition memory, subjects first study a set of items with instructions to remember them for a subsequent memory test and later are shown randomly intermixed studied and non-studied items one at a time and asked to make old/new recognition judgment for each one. We refer to this as the study-test or ST procedure. In a different approach, items are presented one at a time for old/new recognition judgments, with some items being re-presented after varying lags. This is called the continuous recognition, or CR procedure. We speculated that there may be interesting psychological differences between ST and CR, as intuitively the task demands of the two procedures seem to us quite different. In an ST procedure, during the study phase participants do something to encode items, and then they are distracted by some other activity for a while, and then they make recognition judgments about test probes. The participant’s goals and orientation during study and test phases of ST are quite different and they are temporally separated. In contrast, in CR each item (after the first item) is to be processed both as a to-be-remembered stimulus and as a test probe, such that studying and testing are intermingled. Participants typically don’t know how many or few items will intervene between the initial presentation of a stimulus and its representation, and that might encourage them to try to keep more stimuli in mind for a longer period. At the start of this research we did not have specific predictions but we thought that task-demand differences between ST and CR might produce differences in hit or FA rates and/or differences in subjective reports such as confidence ratings and Remember/Know judgments. We also intend to examine response latency for recognition decisions. We have already completed 6 experiments comparing ST and CR and have observed that, for word stimuli, we get more false alarms (FAs), but fewer hits, in CR vs. ST procedures. This experiment uses pictures of everyday objects as the stimuli.

This thesis was scanned from the print manuscript for digital preservation and is copyright the author. Researchers can access this thesis by asking their local university, institution or public library to make a request on their behalf. Monash staff and postgraduate students can use the link in the References field.

Supplemental material, sj-pdf-1-prf-10.1177_02676591221080506 for Utility of cephalic drains in infants receiving extracorporeal membrane oxygenation by Allison T Rose, Joel Davis, Helen O Williams, Matthew Clifton, Matthew Paden, and Sarah D Keene in Perfusion

Supplemental material, sj-pdf-1-prf-10.1177_02676591221080506 for Utility of cephalic drains in infants receiving extracorporeal membrane oxygenation by Allison T Rose, Joel Davis, Helen O Williams, Matthew Clifton, Matthew Paden, and Sarah D Keene in Perfusion

The awarding of grades or marks to student work is traditionally considered a fundamental feature of assessment. Grades became more widely established in the twentieth century becoming ubiquitous across most educational institutions. There is increasing evidence to suggest that grades are not effective tools for promoting or measuring learning. One alternative approach for promoting and measuring learning is "Ungrading," in which no letter grades or marks are given to students. Instead, they are replaced with formative feedback provided through strategies such as individual feedback, peer review and self-assessment. An Ungrading approach promises increased learner motivation, a reduction in stress, and enhanced learner independence. It also helps to develop an improved teacher/learner relationship and opens up new course design possibilities. This paper presents a background to traditional grading policies to set a context. It continues with an introduction to the topic of Ungrading with a brief explanation and rationale for its selection. We ask the question, can Ungrading support a new pedagogy of care for the future of online education? The paper concludes by suggesting strategies for the effective implementation of Ungrading in undergraduate classes to support diverse learner needs.

The awarding of grades or marks to student work is traditionally considered a fundamental feature of assessment. Traditional grades, the awarding of numeric values to student work, date back to the 1600s where Harvard used exit grades to measure and categorize students (Smallwood, 1935). Grades became more widely established in the education sector at the beginning of the twentieth century to deal with increased numbers of students and as a means of communication between educational institutions and third parties, a form of universal measurement. Although becoming ubiquitous across most educational spectrums in the second half of the twentieth century, there is mounting evidence to suggest that grades are not effective tools for measuring learning. A number of institutions and individual practitioners have moved away from grading in the hope of improving motivation, collaboration and lifelong learning for their students (Brilleslyper, et al., 2012) (White & Fantone, 2014) (Sackstein, 2015) (Beckie, 2019). With calls for a ‘Pedagogy of Care’ (Bali, 2020) and a decolonising of curriculum (Begum, & Saini, 2019) new approaches are being explored to replace traditional grading practices., One alternative approach is "ungrading,", in which no letter grades or marks are given to students, has gained momentum. Recent literature (Blum, 2017) (Gibbs, 2019) suggests that ungrading increases motivation reduces stress, enhances independence, helps form new learning habits, makes room for creative work, promotes better communication, and opens up new course design possibilities. Strategies to go gradeless include providing plentiful formative feedback, facilitating peer and self-assessment, teaching students metacognitive skills through reflection, and (if the academic institution requires a final grade) allowing students to grade themselves (Stommel, 2018) (Sackstein, 2015) (Stommel, 2017). The involvement of students as partners in assessment has been shown to enhance motivation, self-critical learning, and performance (Logan, 2009) (Ndoye, 2017) (Panadero & Al-Qassab, 2019). This paper presents three case studies(action research) based on the delivery of undergraduate modules in an Irish Higher education setting using an ‘Ungrading’ approach The 3 case studies describe activities that took place during the 2020-2021 academic year, in the midst of the global Covid pandemic. Two of the modules are from the Creative Digital Media BA Programme, (Multimedia Development 1 & Web Development 2) and a module in IT & Professional Development as part of a BSc in Horticulture. Each case study will detail the rationale for choosing ungrading, mechanics for delivery and reflection based on qualitative feedback from the three practitioners and student cohorts. The paper concludes by suggesting strategies for the effective implementation of ungrading in undergraduate classes to support diverse learner needs.

Correction for ‘Precise measurement of selenium isotopes by HG-MC-ICPMS using a 76–78 double-spike’ by Marie-Laure Pons et al., J. Anal. At. Spectrom., 2020, 35, 320–330, https://doi.org/10.1030/c9ja00331b.

Persistent Absence (missing at least 10% of school over a term) affects 1 in 10 young people in England, with a greater weighting towards those in marginalised communities. It has long-term negative academic, economic, social and psychological outcomes for young people, their families and communities. This study explores the views of three young people in London who have returned to mainstream secondary school after a period of Persistent Absence. It used a Narrative Inquiry qualitative design to analyse and share their stories and experiences. Data was gathered through unstructured interviews with some narrative prompts, and then analysed according to a Narrative Oriented Inquiry model. This first involved dividing texts into two parts: Sjuzet (the way in which the story is told)and Fabula (the sequence of relayed events). A second holistic stage of analysis was employed to answer the question ���what story is the participant trying to tell?��� and to draw out any common themes across the three. The findings illustrate how lonely and overwhelming secondary school can be, and how transition is a deeply difficult time for some young people, with absence being used perhaps as a coping mechanism. They also show the impressive perseverance and effort that these three young people put in to return and how relationships, a sense of agency and self-worth are crucial to their success. Applied to the theories of Second Wave Positive Psychology, the narratives help formulate a tentative model of how young people might experience Persistent Absence as a traumatic event, and move through it to a place of growth, by drawing on the good and the bad elements of their realities. Coming from an ecosystemic and interpretive-constructivist background, the study highlights how important the people and communities around young people are in providing the right conditions for resilience and growth. The thesis concludes by discussing the implications of the findings for future research and Educational Psychology practice.

This thesis was scanned from the print manuscript for digital preservation and is copyright the author. Researchers can access this thesis by asking their local university, institution or public library to make a request on their behalf. Monash staff and postgraduate students can use the link in the References field.

Zircon crystals from the Jack Hills, Western Australia, are one of the few surviving mineralogical records of Earth's first 500 million years and have been proposed to contain a paleomagnetic record of the Hadean geodynamo. A prerequisite for the preservation of Hadean magnetization is the presence of primary magnetic inclusions within pristine igneous zircon. To date no images of the magnetic recorders within ancient zircon have been presented. Here we use high-resolution transmission electron microscopy to demonstrate that all observed inclusions are secondary features formed via two distinct mechanisms. Magnetite is produced via a pipe-diffusion mechanism whereby iron diffuses into radiation-damaged zircon along the cores of dislocations and is precipitated inside nanopores and also during low-temperature recrystallization of radiation-damaged zircon in the presence of an aqueous fluid. Although these magnetites can be recognized as secondary using transmission electron microscopy, they otherwise occur in regions that are indistinguishable from pristine igneous zircon and carry remanent magnetization that postdates the crystallization age by at least several hundred million years. Without microscopic evidence ruling out secondary magnetite, the paleomagnetic case for a Hadean-Eoarchean geodynamo cannot yet been made.

Supplemental material, Manuscript_QHR_S1_20190714 for Men and Miscarriage: A Systematic Review and Thematic Synthesis by Helen M. Williams, Annie Topping, Arri Coomarasamy and Laura L. Jones in Qualitative Health Research

Supplemental material, Manuscript_QHR_S2_20190714 for Men and Miscarriage: A Systematic Review and Thematic Synthesis by Helen M. Williams, Annie Topping, Arri Coomarasamy and Laura L. Jones in Qualitative Health Research

Supplemental material, Manuscript_QHR_S3_20190714 for Men and Miscarriage: A Systematic Review and Thematic Synthesis by Helen M. Williams, Annie Topping, Arri Coomarasamy and Laura L. Jones in Qualitative Health Research

Gender differences between school students have been extensively studied in a range of domains, such as students' interest and academic achievement in so-called non-traditional subjects as well as wellbeing. While researchers agree with the notion that wellbeing is multi-dimensional, there is no agreement about the number and type of those dimensions. M. Lau and J. Bradshaw suggested that various dimensions of wellbeing all contribute to subjective wellbeing, which, they argued, is the essence of wellbeing. The Flourishing Scale "provides a good assessment of overall self-reported psychological wellbeing". G. Carter and I. Liddle also acknowledged the need to differentiate mental health and mental illness, and using an approach based in positive psychology, they developed the Stirling Children's Wellbeing Scale, suitable for children aged 8–15. Students' gender and year level were associated with the likelihood of flourishing, languishing, or having moderate mental health.

Este libro ha sido editado y actualizado para satisfacer las necesidades del AQA examen de secundaria proporcionando grandes oportunidades para el trabajo práctico. Los temas del libro son: salud y seguridad y el uso de sistemas ICT, análisis de problemas y software (crear una hoja de cálculo, crear una página web), diseño de soluciones (ejemplos, elección de un software), selección y uso de dispositivos de almacenamiento, pantallas, impresoras, altavoces, un sistema ICT y sus componentes, los datos y la información, características de los usuarios, transferencia de datos: redes, factores que afectan el uso de las nuevas tecnologías, las consecuencias de su uso y el impacto que provocan. sc Biblioteca de Educación del Ministerio de Educación, Cultura y Deporte; Calle San Agustín, 5 - 3 planta; 28014 Madrid; Tel. +34917748000; biblioteca@mecd.es GBR

Estimates of the volume of the earliest crust based on zircon ages and radiogenic isotopes remain equivocal. Stable isotope systems, such as molybdenum, have the potential to provide further constraints but remain underused due to the lack of complementarity between mantle and crustal reservoirs. Here we present molybdenum isotope data for Archaean komatiites and Phanerozoic komatiites and picrites and demonstrate that their mantle sources all possess subchondritic signatures complementary to the superchondritic continental crust. These results confirm that the present-day degree of mantle depletion was achieved by 3.5 billion years ago and that Earth has been in a steady state with respect to molybdenum recycling. Mass balance modelling shows that this early mantle depletion requires the extraction of a far greater volume of mafic-dominated protocrust than previously thought, more than twice the volume of the continental crust today, implying rapid crustal growth and destruction in the first billion years of Earth’s history.

The lavas associated with mantle plumes may sample domains throughout Earth’s mantle and probe its dynamics. However, plume studies are often only able to take snapshots in time, usually of the most recent plume activity, leaving the chemical and geodynamic evolution of major convective upwellings in Earth’s mantle poorly constrained. Here, we report the geodynamically key information of how the lithology and density of a plume change from plume head phase to tail. We use iron stable isotopes and thermodynamic modeling to show that the Galápagos plume has contained small, nearly constant, amounts of dense recycled crust over its 90-million-year history. Despite a temporal evolution in the amount of recycled crust-derived melt in Galápagos-related lavas, we show that this can be explained by plume cooling alone, without associated changes in the plume’s mantle source; results are also consistent with a plume rooted in a lower mantle low-velocity zone also sampling primordial components.

A potential record of Earth’s magnetic field going back 4.2 billion years (Ga) ago is carried by magnetite inclusions in zircon grains from the Jack Hills. This magnetite may be secondary in nature, however, meaning that the magnetic record is much younger than the zircon crystallization age. Here, we use atom probe tomography to show that Pb-bearing nanoclusters in magnetite-bearing Jack Hills zircons formed during two discrete events at 3.4 and

Recent thermodynamic and experimental studies have suggested that volatile organic compounds (e.g., methane, formate, and acetate) can be produced and stabilized in subduction zones, potentially playing an important role in the deep carbon cycle. However, field evidence for the high-pressure production and storage of solid organic compounds is missing. Here, we examine forearc serpentinite clasts recovered by drilling mud volcanoes above the Mariana subduction zone. Notable correlations between carbon and iron stable-isotope signatures and fluid-mobile element (B, As and Sb) concentrations provide evidence for the percolation of slab-derived CO 2 -rich aqueous fluids through the forearc mantle. The presence of carbonaceous matter rich in aliphatic moieties within high-temperature clasts (>350°C) demonstrates that molecular hydrogen production associated with forearc serpentinization is an efficient mechanism for the reduction and conversion of slab-derived CO 2 -rich fluids into solid organic compounds. These findings emphasize the need to consider the forearc mantle as an important reservoir of organic carbon on Earth.

Selenium (Se) stable isotopes are a new geochemical tool with great potential as a tracer of redox processes and chemical cycling of chalcophiles and volatile elements. However, Se isotope measurements in low-Se samples present a formidable analytical challenge. In this study, we report a new method to measure Se stable isotopes (δ82/78Se; per mil deviation relative to Se NIST SRM 3149) with extremely high precision. Selenium has six stable isotopes and therefore is a good candidate for isotope analysis using a double spike approach, which has the advantage that it can correct for any stable isotope fractionation that may occur during sample processing. We have calibrated a novel 76Se–78Se double spike and have developed a rapid and precise analytical protocol on a multi-collector inductively coupled plasma mass spectrometer using an ESI hydride generation introduction system. Sensitivity is over 1000 V per ppm for the total Se signal; a measurement typically requires 25 ng of natural Se. Argon dimer interferences on masses 76, 78 and 80 were corrected in situ by measuring mass 80. Germanium interferences on masses 74 and 76 were corrected by measuring mass 73 and mass 75 was monitored to correct for arsenic hydride on mass 76. Wash-out times were in the order of 180 s, greatly reduced compared to previous studies that rely on on peak zero argon dimer corrections (wash-out times of up to one hour). The 2 s.e. error for a single analysis typically ranges from 0.01 to 0.025‰ (n = 80) for δ82/78Se. Long-term reproducibility and accuracy were estimated by multiple analyses of the Se Merck standard over numerous different analytical sessions, resulting in a mean δ82/78Se value of −0.989 ± 0.034‰ (n = 93; 2 s.d.), which is in excellent agreement with previous studies.

Lithological heterogeneity is a widely accepted feature of the Earth’s mantle, with recycled crustal material accounting for a significant part of heterogeneity in ocean island basalt (OIB) geochemistry. Fe isotopes have been used to link geochemical heterogeneity in OIB sources to distinct mantle lithologies due to their mineral-specific equilibrium fractionation effects, or their composition, such as incorporation of kinetically-fractionated core liquids entrained from the core-mantle boundary. Here we present Fe isotope data for Samoan shield, and Azores volcanoes, together with a combined phase-equilibria and equilibrium mineral-melt isotope fractionation model. These OIB lavas allow us to study the roles of core-derived and recycled mantle components in generating heavy δ57Fe melts. Heavy δ57Fe correlates with radiogenic isotope signatures of enrichment by a crustal component and not with Fe/Mn or any indicator of core involvement. However, single-stage melting of a MORB-like eclogitic pyroxenite cannot generate the heavy δ57Fe seen in Pitcairn, Azores, and rejuvenated Samoa lavas. Melts of a reaction-zone pyroxenite (commonly suggested to form part of the OIB source), derived from eclogite melts hybridised with peridotite, also fail to generate the heaviest Fe isotopic compositions seen in OIB. Instead, the generation of heavy δ57Fe melts in OIB requires: (1) processes that make subducted eclogite isotopically heavier than its pristine precursor MORB (e.g., hydrothermal alteration, metamorphism, sediment input); (2) lithospheric processing, such as remobilisation of previously frozen small-degree melts, or a contribution from lithospheric material metasomatised by silicate melts; and/or (3) melting conditions that limit the dilution of melts with heavy δ57Fe by ambient lower δ57Fe materials. No single process we consider can generate the heavy δ57Fe seen in the Azores, Pitcairn, and rejuvenated Samoan lavas. Therefore, it cannot be assumed that a pyroxenite lithology derived from recycled crustal material is the sole producer of heavy δ57Fe melts in OIB, nor can these signatures be related to contributions from the Earth’s core. Instead, the observation of heavy δ57Fe OIB melts cannot be ascribed to a unique source or process. This ambiguity reflects the multitude of processes operating from the generation of recycled lithologies through to their mantle melting: from MORB generation, its low temperature alteration, through mantle heterogeneity development and lithospheric processing, to eruption at ocean islands.

Subducted serpentinites have the potential to control the exchange of volatile and redox sensitive elements (e.g., Fe, S, C, N) between the slab, the mantle wedge and the deep mantle. Here we examine the mobility of iron and zinc in serpentinite-derived fluids by using their stable isotopes (δFe and δZn) in high-pressure subducted meta-serpentinites from the Cerro del Almirez massif (Spain). This massif preserves a metamorphic front between antigorite (Atg-serpentinite) and antigorite-olivine-orthopyroxene (transitional lithologies) -bearing serpentinites, and chlorite-bearing harzburgite (Chl-harzburgite), displaying granofels, spinifex and fine-grained recrystallized textures. Those rocks were formed at eclogite facies conditions (1.6–1.9 GPa and 680–710 °C). The mean δFe of all the Cerro del Almirez meta-serpentinites (+0.05 ± 0.01‰) is identical within an error to that of primitive mantle (+0.03 ± 0.03‰). A positive correlation between δFe and indices of peridotite protolith fertility (e.g., AlO/SiO) suggests that the δFe values of Cerro del Almirez samples predominantly reflect protolith compositional variations, likely produced by prior episodes of melt extraction. In contrast, the Zn concentrations ([Zn] = 34–67 ppm) and isotope signatures (δZn = +0.18 – +0.55‰) of the Cerro del Almirez samples show a broad range of values, distinct to those of the primitive mantle ([Zn] = 54 ppm; δZn = +0.16 ± 0.06‰). The Atg-serpentinites ([Zn] = 34–46 ppm; δZn = +0.23 ± 0.06‰) display similar [Zn] and δZn values to those of slab serpentinites from other high-pressure meta-ophiolites. Both [Zn] and δZn increase in transitional lithologies ([Zn] = 45–67 ppm; δZn = +0.30 ± 0.06‰) and Chl-harzburgites with granofels ([Zn] = 38–59 ppm; δZn = +0.33 ± 0.04‰) or spinifex ([Zn] = 48–66 ppm; δZn = +0.43 ± 0.09‰) textures. Importantly, Cerro del Almirez transitional lithologies and Chl-harzburgites display abnormally high [Zn] relative to abyssal peridotites and serpentinites (29–45 ppm) and a positive correlation exists between [Zn] and δZn. This correlation is interpreted to reflect the mobilization of Zn by subduction zone fluids at high pressures and temperatures coupled with significant Zn stable isotope fractionation. An increase in [Zn] and δZn from Atg-serpentinite to Chl-harzburgite is associated with an increase in U/Yb, Sr/Y, Ba/Ce and Rb/Ce, suggesting that both [Zn] and δZn record the interaction of the transitional lithologies and the Chl-harzburgites with fluids that had equilibrated with metasedimentary rocks. Quantitative models show that metasediment derived fluids can have isotopically heavy Zn as a consequence of sediment carbonate dissolution and subsequent Zn complexation with carbonate species in the released fluids (e.g., [ZnHCO(HO)] or [ZnCO(HO)]). Our models further demonstrate that Zn complexation with reduced carbon species cannot produce fluids with heavy δZn signature and hence explain the δZn variations observed in the Chl-harzburgites. The most straightforward explanation for the heavy δZn of the Cerro del Almirez samples is thus serpentinite dehydration accompanied by the open system infiltration of the massif by oxidized, carbonate-rich sediment-derived fluids released during prograde subduction-related metamorphism., We thank G. Nowell (Durham University, UK) for technical support and K. Burton (Durham University, UK) for fruitful discussions. This work was supported by a Natural Environment Research Council (NERC) Deep Volatiles Consortium Grant (NE/M000303/1), a European Research Council (ERC) Starting Grant (HabitablePlanet; 306655) to H. Williams, and by the TelluS Program of CNRS/INSU. B Debret acknowledges financial support by LabEx UnivEarthS (ANR-10-LABX-0023 and ANR-18-IDEX-0001). M. T. Gómez‐Pugnaire, J. A. Padrón-Navarta, and C. Marchesi are thanked for early work and characterization of the samples investigated in the present study. We are grateful to the Sierra Nevada National Park authorities for providing the permit for fieldwork and sampling at the Cerro del Almirez massif. E.I. is supported as a postdoc on an ERC Horizon 2020 advanced grant (SHRED; 833632) awarded to Dr. C. Chauvel (IPG, Paris). C.J.G. and V.L.S.-V. acknowledge funding from the “Spanish Ministry of Science and Innovation” and “Agencia Estatal de Investigación (AEI)” grants no. CGL2016-75224-R and CGL2016-81085-R, and from the “Junta de Andalucía” research group grants RNM-131 and RNM-374. We thank S.-A. Liu, R. Halama and two anonymous reviewers for critical comments on earlier version of this article and careful editorial handling by D.A. Ionov.

Estimates of the volume of the earliest crust based on zircon ages and radiogenic isotopes remain equivocal. Stable isotope\ud systems, such as molybdenum, have the potential to provide further constraints but remain underused due to the lack of complementarity between mantle and crustal reservoirs. Here we present molybdenum isotope data for Archaean komatiites and\ud Phanerozoic komatiites and picrites and demonstrate that their mantle sources all possess subchondritic signatures complementary to the superchondritic continental crust. These results confirm that the present-day degree of mantle depletion was\ud achieved by 3.5 billion years ago and that Earth has been in a steady state with respect to molybdenum recycling. Mass balance\ud modelling shows that this early mantle depletion requires the extraction of a far greater volume of mafic-dominated protocrust\ud than previously thought, more than twice the volume of the continental crust today, implying rapid crustal growth and destruction in the first billion years of Earth’s history

In any instance of learning, a student uses both knowledge related to the topic being studied and knowledge about learning. Our observations of students' knowledge about learning show that it is often quite limited and poorly developed. Many students struggle to develop a detailed description of what happens when they learn. It is disconcerting that students are in this state when there is now available a body of detailed research-based knowledge about learning that has been shown to benefit student achievement. We consider the possibility that this situation is associated with an inappropriate reliance on the belief that appropriate knowledge about learning will be generated through experience. This view underestimates the complexity of the domain of knowledge about learning, complexity that necessitates sustained teaching, and practice that parallels that provided for other knowledge domains.

The purpose of this research is to give a historical account of the educational developments for black students in Fairfax County, Virginia. The research will first address a brief history of education in Virginia. The second and third chapters will respectively address education for black students in the state and pre-Civil War education in Fairfax County. Chapters four and five will focus on the formation of post-Civil War public education in Fairfax County and the education of black students within the county. The author will fit the education of Fairfax County's black students into the context of education within the state of Virginia. Comparisons and contrasts can then be made regarding the quality of education offered to black students in Fairfax County. As with many southern communities, the growth of public education was affected by complacent attitudes, agrarian life styles, poor quality roads and lack of transportation. Fairfax County was no exception. Although numerous private and free schools existed prior to the Civil War, few received black students. The education of the black child, then, was left to the mercy and interest of those around him who chose to teach him basic reading and writing. Alexandria, for example, boasted of a large free black population--many of whom were educated in Alexandria when it was a part of Fairfax County. Both philanthropic and missionary agencies supported education for black students. After the Civil War other schools existed such as the Freedmen's Bureau schools. These schools functioned until 1871. By this time free public education was a reality in Virginia and the issue of placing both black and white children in the same school became the major topic of educational discussion. In an effort to avoid integration black students were sent outside of Fairfax County to Manassas and Washington. After years of struggle, Luther Jackson School was built within the county to educate Fairfax County's black students. Other schools were gradually built to accommodate the educational needs of the county's black students. Even though schools were built to educate black students, there were many disparities in terms of the quality of facilities within the buildings. Following the 1954 Brown Decision outlawing de jure segregation school assignment was not based on race for black or white children. As a result, parents could have a voice in school selection. In reality, the Brown Decision offered black parents more voice as these parents often sent their children to the formerly white schools. The general belief by whites was that black schools were inferior. Many of the formerly all-black schools eventually became administrative offices for Fairfax County Public Schools and black students began attending schools in their home districts. Ed. D.

This article describes, analyses and reflects on the challenges of planning and conducting the evaluation of the KidsMatter Initiative (KMI) in Australian primary schools during the first year of the two-year initiative. The purpose of the evaluation is to inform the Australia-wide rollout of the KMI. The discussion is arranged under four headings: conceptual challenges, design challenges, practical implementation challenges and managing collaborative complexity. Emphasis is placed on how the challenges were theorised as a basis for responding to the requirements of the evaluation. Conclusions include recognising and enabling contributions from diverse stakeholders, using the domain expertise of the evaluation team, operating flexibly to meet the needs and exigencies of the KMI, the clients and the diverse participant groups, maintaining focus on the core conceptual frameworks underlying the KMI and the evaluation, and the implications of the evaluation for developing wider knowledge relating to schools and their effects, as well as about factors contributing to educational change. Refereed/Peer-reviewed