In this paper, we introduce and provide access to daily (1960-2017) and hourly (1993-2017) datasets of snow and meteorological data measured at the Col de Porte site, 1325 m a.s.l., Chartreuse, France. Site metadata and ancillary measurements such as soil properties and masks of the incident solar radiation are also provided. Weekly snow profiles are made available from September 1993 to March 2018. A detailed study of the uncertainties originating from both measurement errors and spatial variability within the measurement site is provided for several variables. We show that the estimates of the ratio of diffuse-to-total shortwave broadband irradiance is affected by an uncertainty of +/- 0.21 (no unit). The estimated root mean square deviation, which mainly represents spatial variability, is +/- 10 cm for snow depth, +/- 25 kg m(-2) for the water equivalent of snow cover (SWE), and +/- 1 K for soil temperature (+/- 0.4 K during the snow season). The daily dataset can be used to quantify the effect of climate change at this site, with a decrease of the mean snow depth (1 December to 30 April) of 39 cm from the 1960-1990 period to the 1990-2017 period (40% of the mean snow depth for 1960-1990) and an increase in temperature of +0.90 K for the same periods. Finally, we show that the daily and hourly datasets are useful and appropriate for driving and evaluating a snowpack model over such a long period. The data are placed on the repository of the Observatoire des Sciences de l'Univers de Grenoble (OSUG) data centre: https://doi.org/10.17178/CRYOBSCLIM.CDP.2018.
Changes in gene expression patterns can reflect the adaptation of organisms to divergent environments. Quantitative real‐time PCR ( qRT ‐ PCR ) is an important tool for ecological adaptation studies at the gene expression level. The quality of the results of qRT ‐ PCR analysis largely depends on the availability of reliable reference genes ( RG s). To date, reliable RG s have not been determined for adaptive evolution studies in insects using a standard approach. Here, we evaluated the reliability of 17 candidate RG s for five Gynaephora populations inhabiting various altitudes of the Tibetan Plateau ( TP ) using four independent (geNorm, NormFinder, BestKeeper, and the deltaCt method) and one comprehensive (RefFinder) algorithms. Our results showed that EF 1‐ α, RPS 15 , and RPS 13 were the top three most suitable RG s, and a combination of these three RG s was the most optimal for normalization. Conversely, RPS 2 , ACT , and RPL 27 were the most unstable RG s. The expression profiles of two target genes ( HSP 70 and HSP 90 ) were used to confirm the reliability of the chosen RG s. Additionally, the expression patterns of four other genes ( GPI , HIF 1A , HSP 20 , and USP ) associated with adaptation to extreme environments were assessed to explore the adaptive mechanisms of TP Gynaephora species to divergent environments. Each of these six target genes showed discrepant expression patterns among the five populations, suggesting that the observed expression differences may be associated with the local adaptation of Gynaephora to divergent altitudinal environments. This study is a useful resource for studying the adaptive evolution of TP Gynaephora to divergent environments using qRT ‐ PCR , and it also acts as a guide for selecting suitable RG s for ecological and evolutionary studies in insects. We evaluated the reliability of 17 candidate RGs for five Gynaephora populations inhabiting divergent altitudes of the Tibetan Plateau. EF1‐α , RPS15 , and RPS13 were the top three suitable RGs, and the combination of the three RGs was the most optimal normalization number. The expression patterns of six genes associated with the adaptation of animals to extreme environments were detected to explore the adaptive mechanisms of Gynaephora to divergent environments.
Persons who are not acclimatized to high altitudes and who ascend to 2500 m are at risk for acute high-altitude illnesses. This article reviews approaches to prevention (e.g., slow ascent, inclusion of a rest day during ascent, and medications) and treatment. Foreword This Journal feature begins with a case vignette highlighting a common clinical problem. Evidence supporting various strategies is then presented, followed by a review of formal guidelines, when they exist. The article ends with the authors' clinical recommendations. Stage A 45-year-old healthy man wishes to climb Mount Kilimanjaro (5895 m) in a 5-day period, starting at 1800 m. The results of a recent exercise stress test were normal; he runs 10 km 4 or 5 times per week and finished a marathon in less than 4 hours last year. He wants to know how he can prevent becoming ill at high altitude and whether training or sleeping under normobaric hypoxic conditions in the weeks before the ascent would be helpful. What would you advise? The Clinical Problem Persons who are not acclimatized and ascend rapidly to high altitudes . . .
Vertical volume emission rate profiles of the OH(3–1) Meinel emission near the mesopause are retrieved from nighttime limb-emission observations with the SCIAMACHY (Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY) instrument on the Envisat satellite. Mean emission altitudes are determined by weighting altitude with the vertical OH(3–1) volume emission rate profile. Analysis of the SCIAMACHY data set from January 2003 to December 2011 shows a clear semi-annual variation of the mean emission altitudes at low latitudes – where SCIAMACHY performs measurements throughout the year – with an amplitude of 0.5–1.0 km. Confirming earlier studies, we find a near constant, or universal, scaling of mean OH emission altitude and vertically integrated emission rate, which can be employed by ground-based observers to infer indirect information on OH emission altitude and its variability, if measurements of OH emission rates are performed. For this purpose we provide climatological fit parameters for the altitude/emission rate relationship. No obvious long-term trends or 11-year solar cycle signatures are present in the OH emission altitude time series, partly contradicting earlier studies. The long-term stability in OH emission altitude at the local time of the SCIAMACHY nighttime observations (10 p.m.) strengthens the use of ground-based OH rotational temperature measurements to study middle atmospheric climate change.
Unlike other methods of estimating the Equilibrium Line Altitude of present or former glaciers from morphometric data (as distinct from direct observations of the glacier mass balance), the Area×Altitude, the Area×Altitude Balance Ratio and the Area×Altitude Balance Index methods take explicit account of hypsometric differences between glaciers and thus yield more reliable results. In addition they offer the means of applying various mass balance/altitude relationships of increasing complexity and examining which of these is most correct; the last of these methods is newly developed to permit the application of any desired relationship. Their general adoption has been restricted hitherto by computational problems, but this objection is removed by the easy-to-use spread sheets presented in this paper. By whatever method estimates are derived, it is essential to validate the optional variables used in the computations and methods for doing this are set out.
High-altitude illness is the collective term for acute mountain sickness (AMS), high-altitude cerebral oedema (HACE), and high-altitude pulmonary oedema (HAPE). The pathophysiology of these syndromes is not completely understood, although studies have substantially contributed to the current understanding of several areas. These areas include the role and potential mechanisms of brain swelling in AMS and HACE, mechanisms accounting for exaggerated pulmonary hypertension in HAPE, and the role of inflammation and alveolar-fluid clearance in HAPE. Only limited information is available about the genetic basis of high-altitude illness, and no clear associations between gene polymorphisms and susceptibility have been discovered. Gradual ascent will always be the best strategy for preventing high-altitude illness, although chemoprophylaxis may be useful in some situations. Despite investigation of other agents, acetazolamide remains the preferred drug for preventing AMS. The next few years are likely to see many advances in the understanding of the causes and management of high-altitude illness.
Haemoglobin levels and differences in glucose metabolism at high altitude may influence the diagnostic performance of testing for diabetes using HbA 1c . We found that the relationship between HbA 1c and fasting plasma glucose (FPG) differed markedly between high‐altitude and sea‐level areas. The relationship between HbA 1c and FPG was quadratic at sea level and linear at high altitude. Corresponding FPG values for an HbA 1c ≥ 48 mmol/mol (≥ 6.5%) cut‐off point, used for the diagnosis of diabetes, were 6.6 and 14.8 mmol/l (120 and 266 mg/dl) at sea level and high altitude, respectively. The sensitivity of HbA 1c to detect abnormal FPG was 87.3% at sea level and 40.9% at high altitude. This suggests a limitation in the performance of HbA 1c to diagnose diabetes at altitude.
Negi, PC, R. Marwaha, S. Asotra, A. Kandoria, N. Ganju, R. Sharma, R.V. Kumar, and R. Bhardwaj. Prevalence of high altitude pulmonary hypertension among the natives of Spiti Valley—A high altitude region in Himachal Pradesh, India. High Alt Med Biol 15:504–510, 2014.—The study aimed to determine the prevalence of high altitude pulmonary hypertension (HAPH) and its predisposing factors among natives of Spiti Valley. A cross-sectional survey study was done on the permanent natives of Spiti Valley residing at an altitude of 3000 m to 4200 m. Demographic characteristics, health behavior, anthropometrics, and blood pressure were recorded. Investigations included recording of 12 lead electrocardiogram (ECG), SaO 2 with pulse oximeter, spirometry and echocardiography study, and measurement of Hb levels using the cynmethhemoglobin method. HAPH was diagnosed using criteria; tricuspid regurgitation (TR) gradient of ≥46 mmHg. ECG evidence of RV overload on 12 lead ECG was documented based on presence of 2 out of 3 criteria; R>S in V1, right axis deviation or RV strain, T wave inversion in V1 and V2. Data of 1087 subjects were analyzed who were free of cardiorespiratory diseases to determine the prevalence of HAPH and its predisposing factors. HAPH was recorded in 3.23% (95% C.I. of 0.9–8.1%) and ECG evidence of right ventricular (RV) overload was 1.5% in the study population. Prevalence of HAPH was not different in men and women 2.63% vs. 3.54% p <0.2. Age (Z statistics of 3.4 p <0.0006), hypoxemia (Z statistics of 2.9 p <0.002), and erythrocythemia (Z statistics of 4.7 p <0.003) were independently associated with HAPH. Altitude of residence was not found to be significantly associated with HAPH, although there was a trend of increasing prevalence with increasing altitude. It can be concluded that HAPH is prevalent in 3.23% of natives of Spiti Valley. Increasing age, erythrocythemia and hypoxemia are independent predisposing factors.