Mass wasting triggered by seasonal CO₂ sublimation under Martian atmospheric conditions: Laboratory experiments

Sublimation is a recognized process by which planetary landscapes can be modified. However, interpretation of whether sublimation is involved in downslope movements on Mars and other bodies is restricted by a lack of empirical data to constrain this mechanism of sediment transport and its influence on landform morphology. Here we present the first set of laboratory experiments under Martian atmospheric conditions which demonstrate that the sublimation of CO2 ice from within the sediment body can trigger failure of unconsolidated, regolith slopes and can measurably alter the landscape. Previous theoretical studies required CO2 slab ice for movements, but we find that only frost is required. Hence, sediment transport by CO2 sublimation could be more widely applicable (in space and time) on Mars than previously thought. This supports recent work suggesting CO2 sublimation could be responsible for recent modification in Martian gullies

Women's perceptions of fertility assessment and counselling six years after attending a Fertility Assessment and Counselling clinic in Denmark

STUDY QUESTION What are women’s perceptions and experience of fertility assessment and counselling 6 years after attending a Fertility Assessment and Counselling (FAC) clinic in Denmark? SUMMARY ANSWER Women viewed the personalized fertility knowledge and advice they received as important aids to decision-making and they felt the benefits outweighed the risks of receiving personalized fertility information. WHAT IS KNOWN ALREADY Many young people wish to become parents in the future. However, research demonstrates there is a gap in women’s and men’s knowledge of fertility and suggests they may be making fertility decisions based on inaccurate information. Experts have called for the development of interventions to increase fertility awareness so that men and women can make informed fertility decisions and achieve their family-building goals. Since 2011, the FAC clinic in Copenhagen, Denmark has provided personalized fertility assessment and guidance based on clinical examination and evaluation of individual risk factors. Available qualitative research showed that attending the FAC clinic increased fertility awareness and knowledge and was experienced as a catalyst for change (e.g. starting to conceive, pursuing fertility treatment, ending a relationship) in women 1-year post-consultation. STUDY DESIGN, SIZE, DURATION The study was a 6-year follow-up qualitative study of 24 women who attended the FAC clinic between January and June 2012. All women were interviewed during a 2-month period from February to March 2018 at Rigshospitalet, their home or office, in Copenhagen, Denmark. Interviews were held in English and ranged between 60 and 94 min (mean 73 min). PARTICIPANTS/MATERIALS, SETTING, METHODS Invitations to participate in an interview-based follow-up study were sent to 141 women who attended the FAC clinic in 2012. In total, 95 women read the invitation, 35 confirmed interest in participating and 16 declined to participate. Twenty-five interviews were booked and 24 interviews held. Interviews followed a semi-structured format regarding reasons for attending the FAC clinic, if/how their needs were met, and perceptions of fertility assessment and counselling. Data were analysed using thematic analysis. MAIN RESULTS AND THE ROLE OF CHANCE At the follow-up interview, women were on average 39.5 years old. Ten were currently single or dating and 14 were married/cohabiting. All were childless when they attended the FAC clinic. At the follow-up interview, 21 women were parents (14 women with one child; 6 with two children; 1 with three children) and the remaining three women intended to have children in the future. The most common reason for originally attending the FAC clinic was to determine how long they could delay childbearing. Most of the women now believed their needs for attending had been met. Those who were dissatisfied cited a desire for more exact (‘concrete’) information as to their remaining years of fertility, although acknowledged that this was likely not realistic. Women stated that they had felt reassured as to their fertility status after attending the FAC clinic whilst receiving the message that they could not delay childbearing ‘too long’. Women viewed personalized fertility knowledge as an important aid to decision-making but cautioned about developing a false sense of security about their fertility and chance of conceiving in the future based on the results. Although women were generally satisfied with their experience, they wished for more time to discuss options and to receive additional guidance after their initial meeting at the FAC clinic. LIMITATIONS, REASONS FOR CAUTION Participants were from a group of Danish women attending the FAC clinic and interviews were conducted in English, which means they are not representative of all reproductive-aged women. Nevertheless, the study group included a broad spectrum of women who achieved parenthood through different means (heterosexual/lesbian relationship, single parent with donor, co-parent) with various family sizes, and women who were currently childless. WIDER IMPLICATIONS OF THE FINDINGS Our study provides support for an individualized approach to fertility education, assessment and counselling provided at a time when the information is relevant to the individual and their current fertility decision-making. The findings suggest that although satisfied with their visit to the FAC clinic, the women wished for more information and guidance after this visit, suggesting that the current intervention may need to be expanded or new interventions developed to meet these additional needs

Synthesis and characterization of UV photocrosslinkable hydrogels with poly(N-vinyl-2-pyrrolidone): Determination of the network mesh size distribution

Hydrogels of poly(n-vinyl-2-pyrrolidone) were produced by UV irradiation of aqueous solutions of the polymer in presence of hydrogen peroxide, used as initiator. The mechanical and the nanostructural properties of the gels were characterized by a combination of experimental techniques including rheology, low field nuclear magnetic resonance spectroscopy (LF-NMR), and small angle X-ray scattering. Different irradiation doses as well as polymer and initiator concentrations were tested in the characterization. The study elucidates the relationship between different methods to estimate the mesh size of the gel polymeric network. Moreover, a novel correlation model was developed based on Chui and Scherer theories for the interpretation of LF-NMR dataset of polymer solutions and networks

DISC - the dust impact sensor and counter on-board Comet Interceptor: Characterization of the dust coma of a dynamically new comet

The Comet Interceptor space mission, selected by ESA in June 2019 as the first F-Class mission, will study a dynamically new comet or an interstellar object by a unique multi-point 'snapshot' measurement. The mission design will allow to complement previous single spacecraft's fly-by cometary observations. The Dust Impact Sensor and Counter (DISC), devoted to the dust coma characterization, is part of the payload selected for Comet Interceptor. It will be mounted on-board two of the three spacecraft, as part of the Dust-Fields -Plasma (DFP) suite, dedicated to understand further: 1) dust in the coma; 2) magnetic field; 3) plasma and energetic neutral atoms. DISC architecture originates from the Impact Sensor subsystems, part of the Grain Impact Analyzer and Dust Accumulator (GIADA) that successfully flew on-board the ESA/Rosetta spacecraft. DISC main scientific objectives are: 1) to define the dust mass distribution for particles in the mass range 10-15 -10-8 kg ejected from the cometary nucleus; 2) to count dust particles with mass > 10-15 kg; 3) to constrain dust particle density/structure. In this paper, we describe DISC design, aims, methods, feasibility and performances evaluations, carried out by real and simulated dust impacts and by retrieving the number of particles, and their corresponding momentum, using the Comet Interceptor's Engineering Dust Coma Model