Temporal variability of tidal and gravity waves during a record long 10-day continuous lidar sounding

Gravity waves (GWs) as well as solar tides are a key driving mechanism for the circulation in the Earth's atmosphere. The propagation of gravity waves is strongly affected by tidal waves as they modulate the mean background wind field and vice versa, which is not yet fully understood and not adequately implemented in many circulation models. The daylight-capable Rayleigh–Mie–Raman (RMR) lidar at Kühlungsborn (54° N, 12° E) typically provides temperature data to investigate both wave phenomena during one full day or several consecutive days in the middle atmosphere between 30 and 75 km altitude. Outstanding weather conditions in May 2016 allowed for an unprecedented 10-day continuous lidar measurement, which shows a large variability of gravity waves and tides on timescales of days. Using a one-dimensional spectral filtering technique, gravity and tidal waves are separated according to their specific periods or vertical wavelengths, and their temporal evolution is studied. During the measurement period a strong 24 h wave occurs only between 40 and 60 km and vanishes after a few days. The disappearance is related to an enhancement of gravity waves with periods of 4–8 h. Wind data provided by ECMWF are used to analyze the meteorological situation at our site. The local wind structure changes during the observation period, which leads to different propagation conditions for gravity waves in the last days of the measurement period and therefore a strong GW activity. The analysis indicates a further change in wave–wave interaction resulting in a minimum of the 24 h tide. The observed variability of tides and gravity waves on timescales of a few days clearly demonstrates the importance of continuous measurements with high temporal and spatial resolution to detect interaction phenomena, which can help to improve parametrization schemes of GWs in general circulation models

Tobacco cigarette smoking and patellar reflex depression

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/117001/1/cpt196910172.pd

First observation of one noctilucent cloud by a twin lidar in two different directions

International audienceIn the early morning hours of 14 July 1999, a noctilucent cloud (NLC) was observed simultaneously by the two branches of a twin lidar system located at the ALOMAR observatory in northern Norway (69° N). The telescopes of the two lidars were pointing vertical (L^) and off the zenith by 30° (L30°). The two lidars detected an enhancement in the altitude profile of backscattered light (relative to the molecular background) for more than 5 h, starting approximately at 01:00 UT. These measurements constitute the detection of one NLC by two lidars under different directions and allow for a detailed study of the morphology of the NLC layer. A cross-correlation analysis of the NLC signals demonstrates that the main structures seen by both lidars are practically identical. This implies that a temporal evolution of the microphysics within the NLC during its drift from one lidar beam to the other is negligible. From the time delay of the NLC structures, a drift velocity of 55?65 m/s is derived which agrees nicely with radar wind measurements. During the observation period, the mean NLC altitude decreases by ~0.5 km/h (=14 cm/s) at both observation volumes. Further-more, the NLC is consistently observed approximately 500 m lower in altitude at L30° compared to L^. Supplementing these data by observations from rocket-borne and ground-based instruments, we show that the general downward progression of the NLC layer through the night, as seen by both lidars, is caused by a combination of particle sedimentation by 4?5 cm/s and a downward directed vertical wind by 9?10 cm/s, whereas a tilt of the layer in drift direction can be excluded

A new description of probability density distributions of polar mesospheric clouds

In this paper we present a new description of statistical probability density functions (pdfs) of polar mesospheric clouds (PMCs). The analysis is based on observations of maximum backscatter, ice mass density, ice particle radius, and number density of ice particles measured by the ALOMAR Rayleigh-Mie-Raman lidar for all PMC seasons from 2002 to 2016. From this data set we derive a new class of pdfs that describe the statistics of PMC events that is different from previous statistical methods using the approach of an exponential distribution commonly named the g distribution. The new analysis describes successfully the probability distributions of ALOMAR lidar data. It turns out that the former g-function description is a special case of our new approach. In general the new statistical function can be applied to many kinds of different PMC parameters, e.g., maximum backscatter, integrated backscatter, ice mass density, ice water content, ice particle radius, ice particle number density, or albedo measured by satellites. As a main advantage the new method allows us to connect different observational PMC distributions of lidar and satellite data, and also to compare with distributions from ice model studies. In particular, the statistical distributions of different ice parameters can be compared with each other on the basis of a common assessment that facilitates, for example, trend analysis of PMC. © Author(s) 2019

Inhibition of glyoxylate conversion to oxalate in cultured human cells by the carbonyl-scavenging drug, aminoguanidine

Calcium oxalate is the most frequent cause of kidney stones, and is responsible for the damage to kidneys and other organs observed in inherited disorders of oxalate metabolism. Most oxalate produced in the body is derived from its metabolic precursor, glyoxylate. Thus, any means of scavenging glyoxylate to a non-toxic product, thereby diverting it away from oxalate synthesis, has considerable therapeutic implications. Here we show that aminoguanidine, a compound with a proven safety record and used for many years to prevent long-term complications of diabetes, binds glyoxylate covalently and reduces its conversion to oxalate by human liver- and lymphocyte-derived cell lines by >90%. We propose that scavenging glyoxylate with aminoguanidine or its congeners may provide a means of reducing oxalate production in vivo, and advocate the tissue culture system described here as a convenient means for testing such agents in vitro. A serendipitous finding to emerge from our study was the abiotic and strongly pH-dependent formation of oxalate from ascorbate, which has implications for the contribution of ascorbate to urine oxalate excretion

Analysis of small-scale structures in lidar observations of noctilucent clouds using a pattern recognition method

International audienceNoctilucent clouds (NLC) have been observed with the ALOMAR Rayleigh/Mie/Raman lidar at 69° N using a temporal resolution of 30 s since 2008. We present an approach to identify and analyze the localized small scale wave structures of the varying altitude of the NLC layers in the range of 5-30 min that may be caused by gravity waves. Small scale gravity waves breaking in the mesopause region contribute notably to the momentum flux but are difficult to observe and to characterize. The approach is based on a template matching method using generalized structures to be identified in the NLC observations. The new method permits the identification of structures that are present in NLC only for a time too short to appear in a Fourier or wavelet spectrum. Without the need for a continuous time series the method can handle multiple NLC layers and data gaps. In the 2000 h of NLC data from the years 2008-2015, we find almost 5000 single wave structures with a total length of 738 h. The structures are found on average 400 m below the NLC centroid altitude and a large number of the structures has a length at the lower limit of 5 min. With the background wind from the meteor radar near ALOMAR a horizontal scale is estimated based on the length of the individual structures. The distribution of horizontal scales shows a peak of wave structures at 15-20 km in accordance with the horizontal wavelengths found by ground-based camera observations of NLC

Communication in cross-cultural consultations in primary care in Europe: the case for improvement. The rationale for the RESTORE FP 7 project

The purpose of this paper is to substantiate the importance of research about barriers and levers to the implementation of supports for cross-cultural communication in primary care settings in Europe. After an overview of migrant health issues, with the focus on communication in cross-cultural consultations in primary care and the importance of language barriers, we highlight the fact that there are serious problems in routine practice that persist over time and across different European settings. Language and cultural barriers hamper communication in consultations between doctors and migrants, with a range of negative effects including poorer compliance and a greater propensity to access emergency services. It is well established that there is a need for skilled interpreters and for professionals who are culturally competent to address this problem. A range of professional guidelines and training initiatives exist that support the communication in cross-cultural consultations in primary care. However, these are commonly not implemented in daily practice. It is as yet unknown why professionals do not accept or implement these guidelines and interventions, or under what circumstances they would do so. A new study involving six European countries, RESTORE (REsearch into implementation STrategies to support patients of different ORigins and language background in a variety of European primary care settings), aims to address these gaps in knowledge. It uses a unique combination of a contemporary social theory, normalisation process theory (NPT) and participatory learning and action (PLA) research. This should enhance understanding of the levers and barriers to implementation, as well as providing stakeholders, with the opportunity to generate creative solutions to problems experienced with the implementation of such interventions

NLC and the background atmosphere above ALOMAR

Noctilucent clouds (NLC) have been measured by the Rayleigh/Mie/Raman-lidar at the ALOMAR research facility in Northern Norway (69° N, 16° E). From 1997 to 2010 NLC were detected during more than 1850 h on 440 different days. Colocated MF-radar measurements and calculations with the Leibniz-Institute Middle Atmosphere (LIMA-) model are used to characterize the background atmosphere. Temperatures as well as horizontal winds at 83 km altitude show distinct differences during NLC observations compared to when NLC are absent. The seasonally averaged temperature is lower and the winds are stronger westward when NLC are detected. The wind separation is a robust feature as it shows up in measurements as well as in model results and it is consistent with the current understanding that lower temperatures support the existence of ice particles. For the whole 14-year data set there is no statistically significant relation between NLC occurrence and solar Lyman-α radiation. On the other hand NLC occurrence and temperatures at 83 km show a significant anti-correlation, which suggests that the thermal state plays a major role for the existence of ice particles and dominates the pure Lyman-α influence on water vapor during certain years. We find the seasonal mean NLC altitudes to be correlated to both Lyman-α radiation and temperature. NLC above ALOMAR are strongly influenced by atmospheric tides. The cloud water content varies by a factor of 2.8 over the diurnal cycle. Diurnal and semidiurnal amplitudes and phases show some pronounced year-to-year variations. In general, amplitudes as well as phases vary in a different manner. Amplitudes change by a factor of more than 3 and phases vary by up to 7 h. Such variability could impact long-term NLC observations which do not cover the full diurnal cycle