Overview of the Role of Environmental Factors in Neurodevelopmental Disorders

Evidence implicates environmental factors in the pathogenesis of diverse complex neurodevelopmental disorders. However, the identity of specific environmental chemicals that confer risk for these disorders, and the mechanisms by which environmental chemicals interact with genetic susceptibilities to influence adverse neurodevelopmental outcomes remain significant gaps in our understanding of the etiology of most neurodevelopmental disorders. It is likely that many environmental chemicals contribute to the etiology of neurodevelopmental disorders but their influence depends on the genetic substrate of the individual. Research into the pathophysiology and genetics of neurodevelopmental disorders may inform the identification of environmental susceptibility factors that promote adverse outcomes in brain development. Conversely, understanding how low-level chemical exposures influence molecular, cellular, and behavioral outcomes relevant to neurodevelopmental disorders will provide insight regarding gene-environment interactions and possibly yield novel intervention strategies

Parallel Driving and Modulatory Pathways Link the Prefrontal Cortex and Thalamus

Pathways linking the thalamus and cortex mediate our daily shifts from states of attention to quiet rest, or sleep, yet little is known about their architecture in high-order neural systems associated with cognition, emotion and action. We provide novel evidence for neurochemical and synaptic specificity of two complementary circuits linking one such system, the prefrontal cortex with the ventral anterior thalamic nucleus in primates. One circuit originated from the neurochemical group of parvalbumin-positive thalamic neurons and projected focally through large terminals to the middle cortical layers, resembling ‘drivers’ in sensory pathways. Parvalbumin thalamic neurons, in turn, were innervated by small ‘modulatory’ type cortical terminals, forming asymmetric (presumed excitatory) synapses at thalamic sites enriched with the specialized metabotropic glutamate receptors. A second circuit had a complementary organization: it originated from the neurochemical group of calbindin-positive thalamic neurons and terminated through small ‘modulatory’ terminals over long distances in the superficial prefrontal layers. Calbindin thalamic neurons, in turn, were innervated by prefrontal axons through small and large terminals that formed asymmetric synapses preferentially at sites with ionotropic glutamate receptors, consistent with a driving pathway. The largely parallel thalamo-cortical pathways terminated among distinct and laminar-specific neurochemical classes of inhibitory neurons that differ markedly in inhibitory control. The balance of activation of these parallel circuits that link a high-order association cortex with the thalamus may allow shifts to different states of consciousness, in processes that are disrupted in psychiatric diseases

The Human Affectome

Over the last decades, the interdisciplinary field of the affective sciences has seen proliferation rather than integration of theoretical perspectives. This is due to differences in metaphysical and mechanistic assumptions about human affective phenomena (what they are and how they work) which, shaped by academic motivations and values, have determined the affective constructs and operationalizations. An assumption on the purpose of affective phenomena can be used as a teleological principle to guide the construction of a common set of metaphysical and mechanistic assumptions—a framework for human affective research. In this capstone paper for the special issue “Towards an Integrated Understanding of the Human Affectome”, we gather the tiered purpose of human affective phenomena to synthesize assumptions that account for human affective phenomena collectively. This teleologically-grounded framework offers a principled agenda and launchpad for both organizing existing perspectives and generating new ones. Ultimately, we hope Human Affectome brings us a step closer to not only an integrated understanding of human affective phenomena, but an integrated field for affective research

The Science Performance of JWST as Characterized in Commissioning

This paper characterizes the actual science performance of the James Webb Space Telescope (JWST), as determined from the six month commissioning period. We summarize the performance of the spacecraft, telescope, science instruments, and ground system, with an emphasis on differences from pre-launch expectations. Commissioning has made clear that JWST is fully capable of achieving the discoveries for which it was built. Moreover, almost across the board, the science performance of JWST is better than expected; in most cases, JWST will go deeper faster than expected. The telescope and instrument suite have demonstrated the sensitivity, stability, image quality, and spectral range that are necessary to transform our understanding of the cosmos through observations spanning from near-earth asteroids to the most distant galaxies.Comment: 5th version as accepted to PASP; 31 pages, 18 figures; https://iopscience.iop.org/article/10.1088/1538-3873/acb29

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Source rocks, bitumens and petroleum inclusions from the Prague Basin (Barrandian, Czech Republic) - constraints for petroleum generation and migration from petrology, organic geochemistry and basin modelling

The Prague Basin (Barrandian, Czech Republic) represents a classical locality for the Lower and Middle Paleozoic in Europe. Although so far no economic hydrocarbon accumulations have been detected, occurrences of biturnens and petroleum inclusions prove the generation and migration of hydrocarbons within the basin. Based on sedimentological and organic geochemical investigations a first systematic approach on the characterisation and classification of bitumens and petroleum inclusions has been carried out. Their relationship with possible source rocks, the thermal history of the basin and petroleum generation-migration has been analysed using field observations and microscopy, geochemical data and numerical simulations . Potential source rocks, ranging from Middle Ordovician to Middle Devonian, have been studied with respect to their source rock quality . Despite the advanced catagenetic stage of most of the screened strata, ranging from 0.75% (Srbsko Fm., Lower Givetian) to 2.34% (Letnd Fm., Middle Ordovician) reflectivity equivalent to vitrinite reflectance (VR, ~qw), total organic carbon (TOC) contents exceeding 1 % have been determined. The richest source rocks can be found in the Silurian where TOC values reach 2.62%. The hydrocarbon potential of Devonian strata is limited to the lowermost Lochkov Fm., directly succeeding the Upper Silurian . Rock Eval and open system pyrolysis data indicate the Silurian PoMry and Litefi Fm. to be the most prolific source rocks, with some residual hydrocarbon potential be recognised for the Middle to Upper Ordovician Letnd and Vinice Fm. Kerogen typing resulted in mixed type IUIII kerogens for all possible source rock horizons. Bitumens were found exclusively in Silurian and Devonian strata, hosted in veins, fossil molds or vuggy porosity. Black solid bitumen was present at all sampled localities, and in some outcrops greenish and orange, semi-liquid and waxy later stage bitumens occurred as well. Black solid bitumens are remnants of oils that have been thermally altered and influenced by weathering effects. Semi-liquid waxy biturnens are optically isotropic, show yellow fluorescence when excited with ultraviolet light and exhibit low reflectance values (<0.2%). They are interpreted as precipitates that have dropped out of ascending and cooling condensates. As these bitumens occur in hostrocks of an advanced catagenetic maturity stage and in fractures circulated by meteoric water, this mechanism must be a young phenomenon and is probably related to Tertiary block tectonics. Petroleum inclusions occur at all bitumen localities and can reach a remarkable size of up to 0.8 mm. Fluids are trapped in calcite and quartz crystals of diagenetic cements and vein mineralisations . In addition to pure aqueous and pure organic inclusions heterogeneous trapping

Quantitative whole oil gas chromatography as a tool for understanding biodegradation processes in oil reservoirs

Quantitative whole oil gas chromatography of oils has been used to examine the effect of moderate biodegradation on 18 oils from the Barrow Island oilfield, Australia. The Barrow Island oils came from different production wells, reservoir horizons and compartments, but have a common source (the Upper Jurassic Dingo Claystone Formation), with some organo-facies differences. Biodegradation resulted in strong depletion of n-alkanes (>95%) from most of the oils, and water washing partially or completely removed benzene and toluene. Other C5–C9 hydrocarbons were variably affected by biodegradation. Quantitation (mg hydrocarbons / g oil) has enabled comparison with less or non-biodegraded oils, and thus estimation of relative % losses of each C5–C9 hydrocarbon. Adjacent methyl groups reduce the susceptibility of an isomer to biodegradation. 2-Methylalkanes are the most susceptible branched alkanes to biodegradation, 3-methylalkanes are the most resistant and 4-methylalkanes have intermediate resistance. For example, 2-methylpentane is depleted ~15% quicker than 3-methylpentane, and 2-methylhexane is depleted ~10% quicker than 3-methylhexane. Similarly, trans-1,2-dimethylcyclopentane is depleted ~35% quicker than 1,1-dimethylcyclopentane, and cis-1,3-dimethylcyclohexane is depleted ~35% quicker than 1,1-dimethylcyclohexane, because cyclic alkanes with gem-dimethyl substituents inhibit bacterial attack. In addition to the position of alkylation, the carbon skeleton and the degree of alkylation also control susceptibility to moderate biodegradation of cyclic, branched and aromatic C5–C9 hydrocarbons. Quantitative data help to better understand bacterial processes operating in petroleum reservoirs. This study shows that the distribution of low molecular weight hydrocarbons in oils is very useful for understanding the dynamic oil migration, mixing and alteration processes that affect many petroleum reservoirs

Influence of depositional environment and early diagenesis on molecular maturity parameters of coals an example from the Taranaki Basin

3 page(s

Geochemical analysis techniques and geological applications of oil-bearing fluid inclusions, with some Australian case studies

Reliable geochemical information of similar quality to conventional analyses of crude oils and source rocks can be obtained from oil-bearing fluid inclusions (FI). Carefully controlled analytical procedures including sample clean-up, procedural blanks and attention to detail are essential for the successful analysis of inclusion oils. The procedures are technically challenging, but if they are carefully followed, successfully analysed samples can include not only those with high abundances of oil inclusions, such as in current or palaeo-oil reservoirs, but also samples with low amounts of oil inclusions, such as those from oil migration pathways or from Proterozoic or even older rocks. A full range of hydrocarbons can be measured from inclusions, including low molecular weight hydrocarbons, n-alkanes, aliphatic biomarkers such as isoprenoids, hopanes and steranes, and aromatic hydrocarbons. There are many geological applications of the analysis of FI oils, which contribute to reducing regional exploration risk. This paper uses Australian case histories to illustrate the main applications of FI oil analysis. These include better constraining oil charge histories of reservoirs and identifying active source rocks previously unknown in a particular basin. The effects of oil-alteration by biodegradation and/or water-washing in the reservoir can be removed, mixing episodes in reservoirs can be deconvoluted, and the effects of drilling mud additives or other contaminants can be eliminated. Furthermore, the hydrocarbon composition and diversity of Earth's early biosphere can be constrained, and secondary migration pathways can be mapped across prospects or basins.20 page(s

Mass spectrometry techniques for analysis of oil and gas trapped in fluid inclusions

27 page(s