Approaching Freshet beneath Landfast Ice in Kugmallit Bay on the Canadian Arctic Shelf: Evidence from Sensor and Ground Truth Data

The Mackenzie River is the largest river in the North American Arctic. Its huge freshwater and sediment load impacts the Canadian Beaufort Shelf, transporting large quantities of sediment and associated organic carbon into the Arctic Ocean. The majority of this sediment transport occurs during the freshet peak flow season (May to June). Mackenzie River-Arctic Ocean coupling has been widely studied during open water seasons, but has rarely been investigated in shallow water under landfast ice in Kugmallit Bay with field-based surveys, except for those using remote sensing. We observed and measured sedimentation rates (51 g m-2 d-1) and the concentrations of chlorophyll a (mean 2.2 ?g L-1) and suspended particulate matter (8.5 mg L-1) and determined the sediment characteristics during early spring, before the breakup of landfast ice in Kugmallit Bay. We then compared these results with comparable data collected from the same site the previous summer. Comparison of organic quality in seston and trapped material demonstrated substantial seasonal differences. The subtle changes in biological and oceanographic variables beneath landfast ice that we measured using sensors and field sampling techniques suggest the onset of a spring melt occurring hundreds of kilometres farther south in the Mackenzie Basin.Le fleuve Mackenzie est le plus grand fleuve de l’Arctique nord-américain. Son énorme bassin d’eau douce et sa masse de sédiments ont des effets sur la plateforme externe de la mer de Beaufort canadienne, transportant ainsi de grandes quantités de sédiments et de carbone organique associé dans l’océan Arctique. La plus grande partie du transport des sédiments se produit pendant la saison haute d’écoulement du courant d’eau douce dans la mer (de mai à juin). Même si le couplage du fleuve Mackenzie et de l’océan Arctique a fait l’objet d’études approfondies durant les saisons d’eau libre, il a rarement été étudié en eau peu profonde sous la banquise de la baie Kugmallit au moyen d’études sur le terrain, sauf dans le cas d’études faisant appel à la télédétection. Nous avons observé et mesuré les taux de sédimentation (51 g m-2 d-1) et les concentrations de chlorophylle a (moyenne de 2,2 ?g L-1) et de matière particulaire en suspension (8,5 mg L-1), puis déterminé les caractéristiques des sédiments au début du printemps, avant la rupture de la banquise dans la baie Kugmallit. Ensuite, nous avons comparé ces résultats à des données comparables recueillies au même emplacement l’été précédent. La comparaison de la qualité organique du seston et des matières emprisonnées faisait ressortir d’importantes différences saisonnières. Les changements subtils sur le plan des variables biologiques et océanographiques sous la banquise que nous avons mesurés à l’aide de capteurs et de techniques d’échantillonnage sur le terrain laissent entrevoir un début de fonte du printemps se produisant à des centaines de kilomètres plus au sud, dans le bassin du Mackenzie

Plastic Bags Prohibition Bill: A developing story of crass legalism aiming to reduce plastic marine pollution in Nigeria

Mismanaged plastic land-based waste entering the marine environment is a growing problem globally. Plastic bag reduction policies have been widely adopted in Africa but are mainly punitive outright legislative bans. Limited evidence exists that document effectiveness of these legislative bans on curbing plastic marine pollution in Africa. In May 2019, the Nigerian government passed the Plastic Bags Prohibition Bill (Bill) which proposed to prohibit the use, manufacture and importation of all plastic bags used for commercial and household packaging. The Bill proposed by the Nigerian government mirrors punitive legislation prevalent elsewhere across Africa. Legislative tools used internationally were compared to the proposed Nigerian Bill and limitations identified. We highlight how the Bill can be redrafted to reflect national policy to improve ocean management. Redrafting the Bill should include proactive measures, such as market-based instruments, proper planning, coordination, implementation and enforcement before final enactment into law

Do’s and don’ts of microplastic research: a comprehensive guide

Microplastics are environmental contaminants consisting of small plastics ≤ 5 mm. Concerns over the adverse effects of microplastics have led to a rapid growth in the available literature despite the lack of harmonized methods and materials. Therefore, the field is becoming increasingly daunting to new researchers. A state-of-theart guide was assembled following a comprehensive literature review of microplastics research with the intent of addressing contemporary challenges, prioritized based on a survey, and introducing best practices. The lack of standardized methods and reference materials, the lack of access to analytical equipment, and the difficulty in working with lower environmental concentrations in laboratory tests (e.g., toxicity assays) remain a great challenge. The present work addresses these issues across three main sections: definitions, sampling, and evaluation of adverse effects. Harmonized methods and greater collaboration were identified as opportunities in this rapidly evolving field. A review of available interlaboratory comparison tests was also conducted to support additional recommendations.Padrão J would like to acknowledge the funding by the Portuguese Foundation for Science and Technology (FCT), European Regional Development Fund (FEDER), Operational Program for Competitiveness Factors (COMPETE), and Portuguese Ministry of Science, Technology and Higher Education (MCTS): [UID/CTM/00264/2021]

Investigating Material Approximations in Spacecraft Radiation Analysis

During the design process, the configuration of space vehicles and habitats changes frequently and the merits of design changes must be evaluated. Methods for rapidly assessing astronaut exposure are therefore required. Typically, approximations are made to simplify the geometry and speed up the evaluation of each design. In this work, the error associated with two common approximations used to simplify space radiation vehicle analyses, scaling into equivalent materials and material reordering, are investigated. Over thirty materials commonly found in spacesuits, vehicles, and human bodies are considered. Each material is placed in a material group (aluminum, polyethylene, or tissue), and the error associated with scaling and reordering was quantified for each material. Of the scaling methods investigated, range scaling is shown to be the superior method, especially for shields less than 30 g/cm2 exposed to a solar particle event. More complicated, realistic slabs are examined to quantify the separate and combined effects of using equivalent materials and reordering. The error associated with material reordering is shown to be at least comparable to, if not greater than, the error associated with range scaling. In general, scaling and reordering errors were found to grow with the difference between the average nuclear charge of the actual material and average nuclear charge of the equivalent material. Based on this result, a different set of equivalent materials (titanium, aluminum, and tissue) are substituted for the commonly used aluminum, polyethylene, and tissue. The realistic cases are scaled and reordered using the new equivalent materials, and the reduced error is shown

A Reference Field for GCR Simulation and an LET-Based Implementation at NSRL

Exposure to galactic cosmic rays (GCR) on long duration deep space missions presents a serious health risk to astronauts, with large uncertainties connected to the biological response. In order to reduce the uncertainties and gain understanding about the basic mechanisms through which space radiation initiates cancer and other endpoints, radiobiology experiments are performed. Some of the accelerator facilities supporting such experiments have matured to a point where simulating the broad range of particles and energies characteristic of the GCR environment in a single experiment is feasible from a technology, usage, and cost perspective. In this work, several aspects of simulating the GCR environment in the laboratory are discussed. First, comparisons are made between direct simulation of the external, free space GCR field and simulation of the induced tissue field behind shielding. It is found that upper energy constraints at the NASA Space Radiation Laboratory (NSRL) limit the ability to simulate the external, free space field directly (i.e. shielding placed in the beam line in front of a biological target and exposed to a free space spectrum). Second, variation in the induced tissue field associated with shielding configuration and solar activity is addressed. It is found that the observed variation is within physical uncertainties, allowing a single reference field for deep space missions to be defined. Third, an approach for simulating the reference field at NSRL is presented. The approach allows for the linear energy transfer (LET) spectrum of the reference field to be approximately represented with discrete ion and energy beams and implicitly maintains a reasonably accurate charge spectrum (or, average quality factor). Drawbacks of the proposed methodology are discussed and weighed against alternative simulation strategies. The neutron component and track structure characteristics of the proposed strategy are discussed in this context

Bathing adaptations in the homes of older adults (BATH-OUT): protocol for a feasibility randomised controlled trial (RCT)

Introduction The Care Act 2014 has placed a responsibility on local authorities in England to provide services that prevent deterioration and minimise the use of other health and social care services. Housing adaptations have been identified as 1 of the 10 most promising prevention services for older adults, with bathing adaptations being the most requested. However, many local authorities have lengthy waiting times which may increase costs, reduce effectiveness and reduce the preventive effect. There is no robust evidence of the effect of these adaptations on: health, well-being and functional ability. Methods and analysis This is a feasibility randomised controlled trial (RCT) with nested qualitative interview study. The RCT will recruit between 40 and 60 people who have been referred for an accessible showering facility, and their carers, from 1 local authority in England. They will be randomised to either usual adaptations (∼3-month wait) or immediate adaptations (no wait). The primary outcome is the feasibility of conducting a powered study. The outcomes assessed will be: health and social care-related quality of life, independence in activities of daily living and bathing, falls and use of health and social care services. Outcomes will be assessed at 3 and 6 months. Preliminary health economic feasibility will be established. Ethics and dissemination Favourable ethical opinion was provided by the Social Care Research Ethics Committee (reference number 16/IEC08/0017). The results of this study will lay the foundations for a further powered study. This would investigate the effect of bathing adaptations on quality of life and whether increased waiting times are associated with poorer outcomes and increased costs. The results have further potential to inform trials of other housing or social care interventions using the novel waiting list control method. Dissemination will include peer-reviewed publications and presentations at national and international conferences. Trial registration number ISRCTN14876332; Pre-results

Gonadotrophin-mediated miRNA expression in testis at onset of puberty in rhesus monkey: Predictions on regulation of thyroid hormone activity and DLK1-DIO3 locus

Molecular mechanisms responsible for the initiation of primate spermatogenesis remain poorly characterized. Previously, 48 h stimulation of the testes of three juvenile rhesus monkeys with pulsatile LH and FSH resulted in down-regulation of a cohort of genes recognized to favor spermatogonia stem cell renewal. This change in genetic landscape occurred in concert with amplification of Sertoli cell proliferation and the commitment of undifferentiated spermatogonia to differentiate. In this report, the non-protein coding small RNA transcriptomes of the same testes were characterized using RNA sequencing: 537 mature micro-RNAs (miRNAs), 322 small nucleolar RNAs (snoRNAs) and 49 small nuclear RNAs (snRNAs) were identified. Pathway analysis of the 20 most highly expressed miRNAs suggested that these transcripts contribute to limiting the proliferation of the primate Sertoli cell during juvenile development. Gonadotrophin treatment resulted in differential expression of 35 miRNAs, 12 snoRNAs and four snRNA transcripts. Ten differentially expressed miRNAs were derived from the imprinted delta-like homolog 1-iodothyronine deiodinase 3 (DLK1-DIO3) locus that is linked to stem cell fate decisions. Four gonadotrophin-regulated expressed miRNAs were predicted to trigger a local increase in thyroid hormone activity within the juvenile testis. The latter finding leads us to predict that, in primates, a gonadotrophin-induced selective increase in testicular thyroid hormone activity, together with the established increase in androgen levels, at the onset of puberty is necessary for the normal timing of Sertoli cell maturation, and therefore initiation of spermatogenesis. Further examination of this hypothesis requires that peripubertal changes in thyroid hormone activity of the testis of a representative higher primate be determined empirically.Fil: Aliberti, Paula. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan". Servicio de Endocrinología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sethi, Rahil. University of Pittsburgh; Estados UnidosFil: Belgorosky, Alicia. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan". Servicio de Endocrinología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Chandran, Uma R.. University of Pittsburgh; Estados UnidosFil: Plant, Tony M.. University of Pittsburgh; Estados UnidosFil: Walker, William H.. University of Pittsburgh; Estados Unido

An Improved Neutron Transport Algorithm for HZETRN

Long term human presence in space requires the inclusion of radiation constraints in mission planning and the design of shielding materials, structures, and vehicles. In this paper, the numerical error associated with energy discretization in HZETRN is addressed. An inadequate numerical integration scheme in the transport algorithm is shown to produce large errors in the low energy portion of the neutron and light ion fluence spectra. It is further shown that the errors result from the narrow energy domain of the neutron elastic cross section spectral distributions, and that an extremely fine energy grid is required to resolve the problem under the current formulation. Two numerical methods are developed to provide adequate resolution in the energy domain and more accurately resolve the neutron elastic interactions. Convergence testing is completed by running the code for various environments and shielding materials with various energy grids to ensure stability of the newly implemented method

Comparative analysis of the contribution of municipal waste management policies to GHG reductions in China

Waste generation and disposal have been a global issue for decades. The total global greenhouse gas (GHG) emissions in 2019 were 49,758 MtCO2e with waste disposal accounting for 3.2%. With rapid urbanization trends, municipal solid waste (MSW) has become a global challenge which needs to be addressed. A large fraction of MSW such as food wastes, e-waste among others still ends up with unregulated dumps or openly burned in low-income countries. As a response, China initiated the ‘zero-waste’ pilot program which has been running since 2019. To investigate the potential contribution of MSW management to GHG reductions, this study selected four ‘zero-waste’ cities in China, namely Shenzhen, Panjin, Xining and Tongling, as case studies to assess the impacts of different MSW management policies on GHG reductions from 2015 to 2019. Results demonstrated that Shenzhen city achieved progress in reducing GHGs, which decreased by more than 40% between 2015 and 2019. This study provides policy recommendations and waste management approaches and practices to optimize MSW management and reduction of GHGs

Micro(nano)plastic toxicity and health effects: Special issue guest editorial

Microplastics (MPs) and nanoplastics (NPs), collectively termed “Micro(nano)plastics [MNPs]” in the special issue, compose the vast majority of plastic contaminants. MPs have become ubiquitous in the global environment (Walker, 2021, Allen et al., 2022) and NPs have also been reported in environmental samples (Cai et al., 2021). MPs have been widely detected in hundreds of animal and plant species (Karbalaei et al., 2019, Litterbase, 2022), including human placentas and blood (Leslie and Depledge, 2020, Prata et al., 2020, Ragusa et al., 2021, Leslie et al., 2022) as MPs are inhaled or consumed via food products and drinking water (Danopoulos et al., 2020, Sequeira et al., 2020, Zhang et al., 2020, Adib et al., 2022). Due to their small sizes, ubiquitous and persistent nature, the potential toxicity and health effects of MNPs have attracted significant attention and spurring rapidly-increasing research efforts (e.g., Guo et al., 2020, Castro-Castellon et al., 2021, Karbalaei et al., 2021, Khoshnamvand et al., 2021, Lahive et al., 2022, Palacio-Cortés et al., 2022). Studies on laboratory animals have mostly focused on aquatic species and have shown accumulation of MNPs in tissues and organs, causing intestinal injuries, increasing oxidative stress, triggering inflammation, neurotoxicity, and impaired development (Castro-Castellon et al., 2021, Karbalaei et al., 2021, Kukkola et al., 2021, Matthews et al., 2021). However, the actual ecological and human health impacts of MNPs are still largely unknown and few published studies have directly investigated the effects of MNPs on humans (Weber et al., 2022). Evaluating the potential adverse ecological and human health effects of MNPs across levels of biological organization has become highly imperative but challenging due to the high heterogeneity of MNPs, unknown environmental concentrations, debated vector effects for associated chemicals, and co-impact with other environmental stressors, such as climate change and other chemical contaminants (Thornton Hampton et al., 2022). Currently, the concentrations of MNPs in the environment may be low, but their increasing inputs are inevitable based on current and projected plastic production data (Borrelle et al., 2020). Therefore, it has become imperative to evaluate the potential ecological and human health impacts of MNPs