Total bacterial number concentration in free tropospheric air above the Alps

Over a period from June to October 2010, we carried out four short campaigns on the northern alpine ridge (High Altitude Research Station Jungfraujoch, 3,450m above sea level) to determine bacterial number concentrations by collecting aerosol with liquid impingers, followed by filtration, fluorescent staining and counting with a microscope. Impinger liquid was also subjected to drop freeze tests to determine the number of ice nucleators. Parallel measurements of 222Rn enabled us to distinguish air masses with no, or little, recent land surface contact (free troposphere, 222Rn≤0.50Bqm−3) from air masses influenced by recent contact with land surface (222Rn>0.50Bqm−3). In free tropospheric air, concentration of total bacteria was on average 3.4×104cellsm−3 (SD=0.8×104cellsm−3). When wind conditions preceding sampling were calm, or when the station was in clouds during sampling, there was no detectable difference in bacterial number concentrations between free tropospheric air and air influenced by recent land surface contact. One campaign was preceded by a storm. Here, recent land surface contact had enriched the air in bacterial cells (up to 7.5×104cellsm−3). Very few of these bacteria may act as ice nucleators in clouds. The median ratio of ice nucleators to the number of bacterial cells in our study was 1.0×10−5. We conclude that injection of bacterial cells into the free troposphere is an intermittent process. Conditions controlling the release of bacteria into near surface air are probably more of a limiting factor than vertical transport and mixing of near surface air into the free tropospher

Soils rich in biological ice-nucleating particles abound in ice-nucleating macromolecules likely produced by fungi

Soil organic matter carries ice-nucleating particles (INPs) the origin of which is hard to define and that are active at slight supercooling. The discovery and characterization of INPs produced by the widespread soil fungus Mortierella alpina permits a more targeted investigation of the likely origin of INPs in soils. We searched for INPs with characteristics similar to those reported for M. alpina in 20 soil samples from four areas in the northern midlatitudes and one area in the tropics. In the 15 samples where we could detect such INPs, they constituted between 1 and 94&thinsp;% (median 11&thinsp;%) of all INPs active at −10&thinsp;°C or warmer (INP−10) associated with soil particles &lt;&thinsp;5&thinsp;µm. Their concentration increased overproportionately with the concentration of INP−10 in soil and seems to be greater in colder climates. Large regional differences and prevalently high concentrations allow us to make inferences regarding their potential role in the atmosphere and the soil.</p

Calcium antagonist induced vasodilation in peripheral, coronary and cerebral vasculature as important factors in the treatment of elderly hypertensives

Increased arteriolar tone is the pathophysiological hallmark of essential hypertension and is determined by the intracellular free calcium concentration in the vascular smooth muscle cell. Calcium influx is an important determinant of vasoconstriction and excess calcium influx-dependent vasoconstriction has been shown by plethysmographical studies in patients with essential hypertension. Calcium antagonists acutely lower BP by reducing calcium influx, calcium concentration and peripheral resistance. The degree of the attendant sympathetic nerve reflex activation and counter-regulatory mechanisms determines the antihypertensive response of the individual. Chronic monotherapy with a calcium antagonist results in an antihypertensive response, which is directly related to the patient's age and pretreatment BP and indirectly related to plasma renin levels. The resulting reduction in after-load neither leads to reduced cerebral blood flow in hypertensive patients, nor aggravates congestive heart failure. Calcium antagonists are a useful alternative to diuretics, primarily in older patients with low renin levels, either alone or combined with any other antihypertensive drug, and provide effective and safe control of blood pressur

Biological residues define the ice nucleation properties of soil dust

Soil dust is a major driver of ice nucleation in clouds leading to precipitation. It consists largely of mineral particles with a small fraction of organic matter constituted mainly of remains of micro-organisms that participated in degrading plant debris before their own decay. Some micro-organisms have been shown to be much better ice nuclei than the most efficient soil mineral. Yet, current aerosol schemes in global climate models do not consider a difference between soil dust and mineral dust in terms of ice nucleation activity. Here, we show that particles from the clay and silt size fraction of four different soils naturally associated with 0.7 to 11.8 % organic carbon (w/w) can have up to four orders of magnitude more ice nucleation sites per unit mass active in the immersion freezing mode at −12 °C than montmorillonite, the nucleation properties of which are often used to represent those of mineral dusts in modelling studies. Most of this activity was lost after heat treatment. Removal of biological residues reduced ice nucleation activity to, or below that of montmorillonite. Desert soils, inherently low in organic content, are a large natural source of dust in the atmosphere. In contrast, agricultural land use is concentrated on fertile soils with much larger organic matter contents than found in deserts. It is currently estimated that the contribution of agricultural soils to the global dust burden is less than 20 %. Yet, these disturbed soils can contribute ice nuclei to the atmosphere of a very different and much more potent kind than mineral dusts

Using radon-222 to distinguish between vertical transport processes at Jungfraujoch

Trace gases measured at Jungfrajoch, a key baseline monitoring station in the Swiss Alps, are tranported from the surface to the alpine ridge by several different processes. On clear days with weak synoptic forcing, thermally-driven upslope mountain winds (anabatic winds) are prevalent. Using hourly radon–222 observations, which are often used to identify air of terrestrial origin, we used the shape of the diurnal cycle to sort days according to the strength of anabatic winds. Radon is ideal as an airmass tracer because it is emitted from soil at a relatively constant rate, it is chemically inert, and decays with a half-life of 3.8 days. Because of its short half-life, radon concentrations are much lower in the free troposphere than in boundary-layer air over land. For comparable radon concentrations, anabatic wind days at Jungfraujoch are different from non-anabatic days in terms of the average wind speed, humidity, air temperature anomalies, and trace species. As a consequence, future studies could be devised which focus on a subset of days, e.g. by excluding anabatic days, with the intention of choosing a set of days which can be more accurately simulated by a transport model. © Author(s) 2014

Influence of atmospheric circulation on turbulent air-sea heat fluxes over the Mediterranean Sea during winter

The influence of the winter atmospheric circulation on the turbulent variables of the air-sea boundary layer in the Mediterranean Sea is investigated. We examine the effects of several climatic indices and the corresponding large scale atmospheric patterns on the above variables by using a correlation analysis. The spatial characteristics and the behavior of the turbulent variables are also examined based on standard deviation and EOF analysis. Two main types of response to the index-specified atmospheric patterns have been identified: (1) A relatively uniform response of the entire basin associated with the influence of the East Atlantic pattern and (2) opposite responses in the western and eastern sub-basins linked mainly to the intrabasin SLP. The latter is a combined effect of the first four modes of atmospheric variability in the North Atlantic/Eurasia region, the North Atlantic Oscillation (NAO), the East Atlantic Pattern (EA), the Scandinavian Pattern (SCAND), and the East Atlantic-West Russia Pattern (EAWR). The two identified responses of the Mediterranean Sea to the atmospheric forcing are also in accordance with the primary modes of variability of the turbulent variables that result in the EOF analysis. All of the statistically independent indices (NAO, EA, SCAND, EAWR) have to be considered in order to fully account for the modulation of the turbulent variables in the Mediterranean Sea. As an example we refer to the mechanism through which, independent modes of atmospheric variability contributed to the Eastern Mediterranean Transient event between 1987 and 1995. © 2012 by the American Geophysical Union.Peer Reviewe

Radon: a universal baseline indicator at sites with contrasting physical settings

The primary goal of World Meteorological Organisation Global Atmosphere Watch (WMO‐GAW) baseline stations is systematic global monitoring of chemical composition of the atmosphere, requiring a reliable, consistent and unambiguous approach for the identification of baseline air. Premier stations in the GAW baseline network span a broad range of physical settings, from remote marine to high‐altitude continental sites, necessitating carefully tailored site‐specific requirements for baseline sampling, data selection, and analysis. Radon‐222 is a versatile and unambiguous terrestrial tracer, widely‐used in transport and mixing studies. Since the majority of anthropogenic pollution sources also have terrestrial origins, radon has become a popular addition to the ‘baseline selection toolkit’ at numerous GAW stations as a proxy for ‘pollution potential’. In the past, detector performance and postprocessing methods necessitated the adoption of a relaxed (e.g. 100 mBq m‐3) radon threshold for minimal terrestrial influence, intended to be used in conjunction with other baseline criteria and analysis procedures, including wind speed, wind direction, particle number, outlier rejection and filtering. However, recent improvements in detector sensitivity, stability and post‐processing procedures have reduced detection limits below 10 mBq m‐3 at Cape Grim and to 25 mBq m‐3 at other baseline stations. Consequently, for suitably sensitive instruments (such as the ANSTO designed and built two‐filter dual‐flow‐loop detectors), radon concentrations alone can be used to unambiguously identify air masses that have been removed from terrestrial sources (at altitude or over ice), or in equilibrium with the ocean surface, for periods of >2‐3 weeks (radon ≤ 40 mBq m‐3). Potentially, radon observations alone can thus provide a consistent and universal (site independent) means for baseline identification. Furthermore, for continental sites with complex topography and meteorology, where true ‘baseline’ conditions may never occur, radon can be used to indicate the least terrestrially‐perturbed air masses, and provide a means by which to apply limits to the level of ‘acceptable terrestrial influence’ for a given application. We demonstrate the efficacy of the radon‐based selection at a range of sites in contrasting physical settings, including: Cape Grim (Tasmania), Cape Point (South Africa), Mauna Loa (Hawaii), Jungfraujoch (Switzerland) and Schneefernerhaus (Germany).Bureau of Meteorology and CSIRO Oceans and Atmosphere,Climate Science Centre

Association of calcemia and serum vitamin D with 24H-urinary calcium excretion in a swiss population-based study

Background: Elevated urinary calcium excretion is associated with reduced bone mineral density. Population-based data on urinary calcium excretion are scarce. We explored the association of serum calcium and circulating levels of vitamin D (including 25(OH)D2 and 25(OH)D3) with urinary calcium excretion in men and women in a population-based study. Methods: We used data from the "Swiss Survey on Salt" conducted between 2010 and 2012 and including people aged 15 years and over. Twenty-four hour urine collection, blood analysis, clinical examination and anthropometric measures were collected in 11 centres from the 3 linguistic regions of Switzerland. Vitamin D was measured centrally using liquid chromatography - tandem mass spectrometry. Hypercalciuria was defined as urinary calcium excretion &gt;0.1 mmol/kg/24h. Multivariable linear regression was used to explore factors associated with 24-hour urinary calcium excretion (mmol/24h) squared root transformed, taken as the dependant variable. Vitamin D was divided into monthspecific tertiles with the first tertile having the lowest value and the third tertile having the highest value. Results: The 669 men and 624 women had mean (SD) age of 49.2 (18.1) and 47 (17.9) years and a prevalence of hypercalciuria of 8.9% and 8.0%, respectively. In adjusted models, the association of urinary calcium excretion with protein-corrected serum calcium was (β coefficient &#x81;} standard error, according to urinary calcium squared root transformed) 1.125 &#x81;} 0.184 mmol/L per square-root (mmol/24h) (P&lt;0.001) in women and 0.374 &#x81;} 0.224 (P=0.096) in men. Men in the third month-specific vitamin D tertile had higher urinary calcium excretion than men in the first tertile (0.170 &#x81;} 0.05 nmol/L per mmol/24h, P=0.001) and the corresponding association was 0.048 &#x81;} 0.043, P= 0.272 in women. Conclusion: About one in eleven person has hypercalciuria in the Swiss population. The positive association of serum calcium with urinary calcium excretion was steeper in women than in men, independently of menopausal status. Circulating vitamin D was associated positively with urinary calcium excretion only in men. The reasons underlying the observed sex differences in the hormonal control of urinary calcium excretion need to be explored in further studies

Blood Omega-3 Fatty Acids Are Inversely Associated With Albumin-Creatinine Ratio in Young and Healthy Adults (The Omega-Kid Study).

Background: Omega-3 fatty acids are associated with a lower risk of cardiovascular disease (CVD) and with beneficial effects on CV risk factors. The albumin-creatinine ratio (ACR) is a risk factor for CVD, all-cause mortality and accelerated glomerular filtration rate (GFR) decline in the general population. We aimed to investigate the association between n-3 PUFAS and ACR in heathy individuals with preserved GFR. Design and Methods: The present cross-sectional analysis is part of the GAPP study, a population-based cohort of healthy adults aged 25-41 years. Individuals with known CVD, diabetes, or a BMI >35 kg/m2 were excluded. eGFR was calculated according to the combined Creatinine/Cystatin C CKD-EPI formula. ACR was obtained from a fasting morning urine sample. The Omega-3 Index (relative amount of EPA and DHA of total fatty acids in %) was obtained from whole blood aliquots. Results: Overall, 2001 participants (median age 37 years IQR 31; 40, 53% female) were included in this analysis. Median Omega-3 Index was 4.59 (IQR 4.06; 5.25) and median eGFR 111 ml/min/1.73 m2 (IQR 103; 118). Median ACR was 0.14 mg/mmol (IQR 0; 0.43). We found a significant inverse association of the Omega-3 Index with ACR (ratio 0.84, 95%CI 0.73-0.96; p = 0.011) which remained after comprehensive adjustment (ratio 0.86, 95%CI 0.74-1.00; p = 0.048). No association of the Omega-3 Index with eGFR was found. The adjusted difference in eGFR per 1-unit increase in Omega3-Index was -0.21 (95%CI -0.76; 0.35; p = 0.47). Conclusions: A higher Omega-3 Index was significantly associated with lower ACR in this young and healthy population with preserved eGFR. Omega-3 fatty acids may exhibit cardio- and nephroprotective effects in healthy individuals through modulation of ACR

Towards a universal “baseline” characterisation of air masses for high- and low-altitude observing stations using Radon-222

We demonstrate the ability of atmospheric radon concentrations to reliably and unambiguously identify local and remote terrestrial influences on an air mass, and thereby the potential for alteration of trace gas composition by anthropogenic and biogenic processes. Based on high accuracy (lower limit of detection 10–40 mBq m–3), high temporal resolution (hourly) measurements of atmospheric radon concentration we describe, apply and evaluate a simple two-step method for identifying and characterising constituent mole fractions in baseline air. The technique involves selecting a radon-based threshold concentration to identify the “cleanest” (least terrestrially influenced) air masses, and then performing an outlier removal step based on the distribution of constituent mole fractions in the identified clean air masses. The efficacy of this baseline selection technique is tested at three contrasting WMO GAW stations: Cape Grim (a coastal low-altitude site), Mauna Loa (a remote high-altitude island site), and Jungfraujoch (a continental high-altitude site). At Cape Grim and Mauna Loa the two-step method is at least as effective as more complicated methods employed to characterise baseline conditions, some involving up to nine steps. While it is demonstrated that Jungfraujoch air masses rarely meet the baseline criteria of the more remote sites, a selection method based on a variable monthly radon threshold is shown to produce credible “near baseline” characteristics. The seasonal peak-to-peak amplitude of recent monthly baseline CO2 mole fraction deviations from the long-term trend at Cape Grim, Mauna Loa and Jungfraujoch are estimated to be 1.1, 6.0 and 8.1 ppm, respectively