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<p>Freezing is an important factor in soil degradation. In order to predict soil erosion in mountainous areas, the freezing process and the frequency and extent of freezing must be understood. This study aims to identify a relationship between air temperature and a depth of freezing, taking into account soil water content. The soil is considered to be frozen when all the free water within the pores freezes which, according to our numerical model, mainly occurs at temperatures slightly below 0°C. On the other hand, the temperature is not homogeneous in the soil as it is driven by the process of heat diffusion from the soil-atmosphere interface to depth, controlled by soil thermal conductivity and heat capacity, which depend on ice and water contents. As a consequence, the relationship between air temperature and the thickness of the frozen layer is not direct, and the relevance of using air temperature as a measure of frozen depth is to be evaluated.</p> <p>A small N-S-oriented claystone ridge in an Eastern Pyrenees badland is being monitored. A series of thermometers, water content sensors, and specific heat sensors are collecting data in 5-minute intervals on both sides of the ridge. The data show an attenuation of temperature oscillation with an increasing depth and a time delay of the surface temperature propagation. The differences in the soil temperatures on the north and south side are moreover showing the importance of solar radiation in the process. These observations are further integrated into a procedure allowing for the analysis of possible ad-hoc relationships between current and past air temperature and depth of the frozen layer.</p>

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BackgroundAmbulatory surgery is often followed by the development of nausea & vomiting (N/V). Although risk factors for postoperative nausea & vomiting (PONV) are often studied, PONV is not well understood in context of a patient’s home. This is especially troublesome given the potential consequences of postdischarge nausea & vomiting (PDNV), which include major discomfort and hospital readmission.MethodsIn this retrospective cohort study, data from 10,231 adult patients undergoing ambulatory surgery with general anesthesia were collected and analyzed. Multivariable multinomial logistic regression was used to assess the association between patient & operative characteristics (including age, body mass index (BMI), American Society of Anesthesiologists (ASA) classification, current smoker status, and intra & postoperative opioid usage) and the odds of experiencing N/V only in the postanesthesia care unit (PACU), only at home, or in the PACU and at home, as compared to not experiencing N/V at all. ResultsIn this study, 17.8% of all patients developed N/V in at least one location following ambulatory surgery with general anesthesia. Patients who experienced N/V in the PACU had 3.05 (95% confidence interval: 2.55-3.65) times the risk of reporting N/V at home than those who did not. Multivariable multinomial logistic regression found that younger age, greater hydromorphone use, and female sex were associated with increased likelihood of experiencing N/V in all settings. Increased morphine usage was found to be associated with greater odds of experiencing Home only and PACU plus Home N/V, but not PACU only N/V. Greater oxycodone and volatile anesthetic usage were associated with lower and higher odds of experiencing PACU only N/V respectively, but neither were significantly associated with Home only and PACU plus Home N/V.ConclusionsPatients experiencing N/V in the PACU are observed to develop PDNV disproportionately. N/V at home and N/V in the PACU, while having some overlap, are associated with several unique indicators, including usage of oxycodone, morphine, and volatile anesthetics. More investigation into PDNV specific indicators and prevention strategies is warranted. Trial RegistrationN/A

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