The Holy Grail: A road map for unlocking the climate record stored within Mars' polar layered deposits

In its polar layered deposits (PLD), Mars possesses a record of its recent climate, analogous to terrestrial ice sheets containing climate records on Earth. Each PLD is greater than 2 ​km thick and contains thousands of layers, each containing information on the climatic and atmospheric state during its deposition, creating a climate archive. With detailed measurements of layer composition, it may be possible to extract age, accumulation rates, atmospheric conditions, and surface activity at the time of deposition, among other important parameters; gaining the information would allow us to “read” the climate record. Because Mars has fewer complicating factors than Earth (e.g. oceans, biology, and human-modified climate), the planet offers a unique opportunity to study the history of a terrestrial planet’s climate, which in turn can teach us about our own planet and the thousands of terrestrial exoplanets waiting to be discovered. During a two-part workshop, the Keck Institute for Space Studies (KISS) hosted 38 Mars scientists and engineers who focused on determining the measurements needed to extract the climate record contained in the PLD. The group converged on four fundamental questions that must be answered with the goal of interpreting the climate record and finding its history based on the climate drivers. The group then proposed numerous measurements in order to answer these questions and detailed a sequence of missions and architecture to complete the measurements. In all, several missions are required, including an orbiter that can characterize the present climate and volatile reservoirs; a static reconnaissance lander capable of characterizing near surface atmospheric processes, annual accumulation, surface properties, and layer formation mechanism in the upper 50 ​cm of the PLD; a network of SmallSat landers focused on meteorology for ground truth of the low-altitude orbiter data; and finally, a second landed platform to access ~500 ​m of layers to measure layer variability through time. This mission architecture, with two landers, would meet the science goals and is designed to save costs compared to a single very capable landed mission. The rationale for this plan is presented below. In this paper we discuss numerous aspects, including our motivation, background of polar science, the climate science that drives polar layer formation, modeling of the atmosphere and climate to create hypotheses for what the layers mean, and terrestrial analogs to climatological studies. Finally, we present a list of measurements and missions required to answer the four major questions and read the climate record. 1. What are present and past fluxes of volatiles, dust, and other materials into and out of the polar regions? 2. How do orbital forcing and exchange with other reservoirs affect those fluxes? 3. What chemical and physical processes form and modify layers? 4. What is the timespan, completeness, and temporal resolution of the climate history recorded in the PLD

The Holy Grail: A road map for unlocking the climate record stored within Mars' polar layered deposits

In its polar layered deposits (PLD), Mars possesses a record of its recent climate, analogous to terrestrial ice sheets containing climate records on Earth. Each PLD is greater than 2 ​km thick and contains thousands of layers, each containing information on the climatic and atmospheric state during its deposition, creating a climate archive. With detailed measurements of layer composition, it may be possible to extract age, accumulation rates, atmospheric conditions, and surface activity at the time of deposition, among other important parameters; gaining the information would allow us to “read” the climate record. Because Mars has fewer complicating factors than Earth (e.g. oceans, biology, and human-modified climate), the planet offers a unique opportunity to study the history of a terrestrial planet’s climate, which in turn can teach us about our own planet and the thousands of terrestrial exoplanets waiting to be discovered. During a two-part workshop, the Keck Institute for Space Studies (KISS) hosted 38 Mars scientists and engineers who focused on determining the measurements needed to extract the climate record contained in the PLD. The group converged on four fundamental questions that must be answered with the goal of interpreting the climate record and finding its history based on the climate drivers. The group then proposed numerous measurements in order to answer these questions and detailed a sequence of missions and architecture to complete the measurements. In all, several missions are required, including an orbiter that can characterize the present climate and volatile reservoirs; a static reconnaissance lander capable of characterizing near surface atmospheric processes, annual accumulation, surface properties, and layer formation mechanism in the upper 50 ​cm of the PLD; a network of SmallSat landers focused on meteorology for ground truth of the low-altitude orbiter data; and finally, a second landed platform to access ~500 ​m of layers to measure layer variability through time. This mission architecture, with two landers, would meet the science goals and is designed to save costs compared to a single very capable landed mission. The rationale for this plan is presented below. In this paper we discuss numerous aspects, including our motivation, background of polar science, the climate science that drives polar layer formation, modeling of the atmosphere and climate to create hypotheses for what the layers mean, and terrestrial analogs to climatological studies. Finally, we present a list of measurements and missions required to answer the four major questions and read the climate record. 1. What are present and past fluxes of volatiles, dust, and other materials into and out of the polar regions? 2. How do orbital forcing and exchange with other reservoirs affect those fluxes? 3. What chemical and physical processes form and modify layers? 4. What is the timespan, completeness, and temporal resolution of the climate history recorded in the PLD

Unlocking the Climate Record Stored within Mars’ Polar Layered Deposits

In the icy beds of its polar layered deposits (PLD), Mars likely possesses a record of its recent climate history, analogous to terrestrial ice sheets that contain records of Earth's past climate. Both northern and southern PLDs store information on the climatic and atmospheric state during the deposition of each layer (WPs: Becerra et al.; Smith et al). Reading the climate record stored in these layers requires detailed measurements of layer composition, thickness, isotope variability, and near-surface atmospheric measurements. We identify four fundamental questions that must be answered in order to interpret this climate record and decipher the recent climatic history of Mars: 1. Fluxes: What are the present and past fluxes of volatiles, dust, and other materials into and out of the polar regions? 2. Forcings: How do orbital/axial forcing and exchange with other reservoirs affect those fluxes? 3. Layer Processes: What chemical and physical processes form and modify layers? 4. Record: What is the timespan, completeness, and temporal resolution of the climate history recorded in the PLD? In a peer reviewed report (1), we detailed a sequence of missions, instruments, and architecture needed to answer these questions. Here, we present the science drivers and a mission concept for a polar lander that would enable a future reading of the past few million years of the Martian climate record. The mission addresses as-yet-unachieved science goals of the current Decadal Survey and of MEPAG for obtaining a record of Mars climate and has parallel goals to the NEXSAG and ICE-SAG reports

Product-access challenges to menstrual health throughout the COVID-19 pandemic among a cohort of adolescent girls and young women in Nairobi, Kenya

Background Access to menstrual hygiene products enables positive health for adolescent girls and young women (AGYW). Among AGYW in Nairobi, Kenya, this prospective mixed-methods study characterised menstrual health product-access challenges at two time points during the COVID-19 pandemic; assessed trajectories over the pandemic; and examined factors associated with product-access trajectories. Methods Data were collected from an AGYW cohort in August-October 2020 and March-June 2021 (n=591). The prevalence of menstrual health product-access challenges was calculated per timepoint, with trajectories characterizing product-access challenges over time. Logistic regression models examined associations with any product-access challenge throughout the pandemic; multinomial and logistic regressions further assessed factors associated with trajectories. Qualitative data contextualize results. Findings In 2020, 52.0% of AGYW experienced a menstrual health product-access challenge; approximately six months later, this proportion dropped to 30.3%. Product-access challenges during the pandemic were heightened for AGYW with secondary or lower education (aOR=2.40; p < 0.001), living with parents (aOR=1.86; p=0.05), not the prime earner (aOR=2.27; p=0.05); and unable to meet their basic needs (aOR=2.25; p < 0.001). Between time points, 38.0% experienced no product-access challenge and 31.7% resolved, however, 10.2% acquired a challenge and 20.1% experienced sustained challenges. Acquired product-access challenges, compared to no challenges, were concentrated among those living with parents (aOR=3.21; p=0.05); multinomial models further elucidated nuances. Qualitative data indicate deprioritization of menstrual health within household budgets as a contributor. Interpretation Menstrual health product-access challenges are prevalent among AGYW during the pandemic; barriers were primarily financial. Results may reflect endemic product-access gaps amplified by COVID-specific constraints. Ensuring access to menstrual products is essential to ensure AGYW's health needs. Copyright (C) 2022 The Author(s). Published by Elsevier Ltd

Needs and unmet needs for support services for recently pregnant intimate partner violence survivors in Ethiopia during the COVID-19 pandemic

Abstract Background Globally, 2–14% of women experience intimate partner violence (IPV) during pregnancy. Timely response to IPV is critical to mitigate related adverse health outcomes. Barriers to accessing limited IPV support services are pervasive in low- and middle-income countries (LMICs), such as Ethiopia; key barriers include mistrust, stigmatization, and self-blame, and discourage women from disclosing their experiences. Infection control measures for COVID-19 have the potential to further disrupt access to IPV services. Methods In-depth qualitative interviews were undertaken from October-November 2020 with 24 women who experienced IPV during recent pregnancy to understand the needs and unmet needs of IPV survivors in Ethiopia amid the COVID-19 pandemic. Trained qualitative interviewers used a structured note-taking tool to allow probing of experiences, while permitting rapid analysis for timely results. Inductive thematic analysis identified emergent themes, which were organized into matrices for synthesis. Results Qualitative themes center around knowledge of IPV services; experiences of women in seeking services; challenges in accessing services; the impact of COVID-19 on resource access; and persistent unmet needs of IPV survivors. Notably, few women discussed the violence they experienced as unique to pregnancy, with most referring to IPV over an extended period, both prior to and during COVID-19 restrictions. The majority of IPV survivors in our study heavily relied on their informal network of family and friends for protection and assistance in resolving the violence. Though formal IPV services remained open throughout the pandemic, restrictions resulted in the perception that services were not available, and this perception discouraged survivors from seeking help. Survivors further identified lack of integrated and tailored services as enduring unmet needs. Conclusions Results reveal a persistent low awareness and utilization of formal IPV support and urge future policy efforts to address unmet needs through expansion of services by reducing socio-cultural barriers. COVID-19 impacted access to both formal and informal support systems, highlighting needs for adaptable, remote service delivery and upstream violence prevention. Public health interventions must strengthen linkages between formal and informal resources to fill the unmet needs of IPV survivors in receiving medical, psychosocial, and legal support in their home communities

FAM20A mutations can cause enamel-renal syndrome (ERS).

Enamel-renal syndrome (ERS) is an autosomal recessive disorder characterized by severe enamel hypoplasia, failed tooth eruption, intrapulpal calcifications, enlarged gingiva, and nephrocalcinosis. Recently, mutations in FAM20A were reported to cause amelogenesis imperfecta and gingival fibromatosis syndrome (AIGFS), which closely resembles ERS except for the renal calcifications. We characterized three families with AIGFS and identified, in each case, recessive FAM20A mutations: family 1 (c.992G>A; g.63853G>A; p.Gly331Asp), family 2 (c.720-2A>G; g.62232A>G; p.Gln241_Arg271del), and family 3 (c.406C>T; g.50213C>T; p.Arg136* and c.1432C>T; g.68284C>T; p.Arg478*). Significantly, a kidney ultrasound of the family 2 proband revealed nephrocalcinosis, revising the diagnosis from AIGFS to ERS. By characterizing teeth extracted from the family 3 proband, we demonstrated that FAM20A(-/-) molars lacked true enamel, showed extensive crown and root resorption, hypercementosis, and partial replacement of resorbed mineral with bone or coalesced mineral spheres. Supported by the observation of severe ectopic calcifications in the kidneys of Fam20a null mice, we conclude that FAM20A, which has a kinase homology domain and localizes to the Golgi, is a putative Golgi kinase that plays a significant role in the regulation of biomineralization processes, and that mutations in FAM20A cause both AIGFS and ERS

Backscatter Scanning Electron Micrographs (bSEMs) of molar (#18) roots.

<p><i>A:</i> The bSEM of molar after it was cut sagitally (mesial-distally). <i>B:</i> Higher magnification of smaller box in A showing the layered build-up resembling cellular cementum. Arrowheads mark the dentin-cementum border. <i>C–D:</i> Higher magnifications of the larger box in A showing the thick layers of “cellular cementum” covering the roots. In panel D a dark line is placed at the dentin surface. <i>E:</i> Higher magnification of the larger box in panel C showing the thick layers of “cellular cementum” covering the roots and how the lamellar pattern suggests that deposition of these layers was punctuated by periods of resorption that sometimes penetrated into the dentin. <i>F–G:</i> Higher magnification of the smaller box in panel C also showing how deposition of the layers of acellular cementum was punctuated by resorption that sometimes penetrated into the dentin.</p

Scanning Electron Micrographs (SEMs) of molar (#18) occlusal surface.

<p><i>A:</i> Low magnification view of occlusal surface after partially cutting and then splitting the tooth sagitally (mesial-distal direction) for SEM analyses (bar: 1 mm). The boxes, from top to bottom, are locations of higher magnification views shown in B–E, respectively. <i>B:</i> Region showing knob-like calcifications (bar: 100 µm). <i>C:</i> Region where dentinal tubules reach the surface (bar: 10 µm); <i>D:</i> Region showing a relatively smooth surface (bar: 10 µm). <i>E:</i> Region from edge of crown (bar: 100 µm); <i>F:</i> Higher magnification of box in panel E showing no true enamel and apparent resorption lacunae (bar: 10 µm).</p

Images of <i>FAM20A</i>^−/− tooth #18.

<p><i>A:</i> Photographs of #18 after cutting it sagitally. <i>B:</i> Photographs of a wild-type molar after cutting it sagitally. <i>C:</i> Photograph of #18 before sectioning. <i>D:</i> Occlusal view of #18 by photograph (top) and 3-D μ-CT image. <i>E:</i> 3-D μ-CT image of inside #18. Note the hollow area in the crown and the calcified pulp chamber. <i>F:</i> 3-D μ-CT image of #18. Note the shortness of the crown, which as apparently greatly diminished by resorption.</p

Backscatter Scanning Electron Micrographs (bSEMs) of molar (#32).

<p><i>A:</i> The bSEM of molar after it was cut sagitally (mesial-distally). <i>B:</i> Rough “enamel” (e) covering sclerotic dentin. <i>C:</i> Acellular cementum covering sclerotic root dentin. <i>D–E:</i> Highly mineralized pulp or radicular calcifications (pc) comprised of coalesced spheres above the root furcation and associated with a less mineralized material that contacts dentin (d). <i>F:</i> The radicular area appears to be comprised entirely of acellular cementum (ac) or lamellar bone from the furcation to the highly mineralized coalesced spheres. <i>G:</i> Root dentin covered with a thick layer of acellular cementum (ac) or bone. A thin line of more highly mineralized material, possibly cementum (c), separates these layers. <i>H:</i> The material covering root dentin is deposited in layers and sometimes fills in areas of localized root resorption.</p