Two-beam lidar measurements in a non-homogeneous wind field

Nacelle based wind lidars are designed to sit atop a wind turbine structure and make measurements at given distances from it. Most times the lidar faces the turbine’s upstream direction to sense oncoming wind. Two lidars were set up looking upstream on two adjacent offshore turbines in Denmark. The case considered was for when the turbines were oriented such that one lidar was looking into the free stream while the other lidar had one beam in the first turbine’s wake and the other beam in near free stream conditions. This enabled the possibility to look at horizontal wind speeds reconstructed inside homogeneous and non-homogeneous wind fields. Data for the two lidars were processed and averaged over different intervals. Correlations of radial and horizontal wind speeds in different wind fields were performed. Results in this case show horizontal wind speeds reconstructed in non-homogeneous field similar to those reconstructed in a (assumed) homogeneous one

Distribution of plastic polymer types in the marine environment ; a meta-analysis

Despite growing plastic discharge into the environment, researchers have struggled to detect expected increases of marine plastic debris in sea surfaces, sparking discussions about “missing plastics” and final sinks, which are hypothesized to be coastal and deep-sea sediments. While it holds true that the highest concentrations of plastic particles are found in these locations (103-104 particles m−3 in sediments vs. 0.1–1 particles m−3 in the water column), our meta-analysis also highlights that in open oceans, microplastic polymer types segregated in the water column according to their density. Lower density polymers, such as polypropylene and polyethylene, dominated sea surface samples (25% and 42%, respectively) but decreased in abundance through the water column (3% and 2% in the deep-sea, respectively), whereas only denser polymers (i.e. polyesters and acrylics) were enriched with depth (5% in surface seawater vs. 77% in deep-sea locations). Our meta-analysis demonstrates that some of the most abundant and recalcitrant manufactured plastics are more persistent in the sea surface than previously anticipated and that further research is required to determine the ultimate fate of these polymers as current knowledge does not support the deep sea as the final sink for all polymer types

Development and Validation of a Risk Score for Chronic Kidney Disease in HIV Infection Using Prospective Cohort Data from the D:A:D Study

Ristola M. on työryhmien DAD Study Grp ; Royal Free Hosp Clin Cohort ; INSIGHT Study Grp ; SMART Study Grp ; ESPRIT Study Grp jäsen.Background Chronic kidney disease (CKD) is a major health issue for HIV-positive individuals, associated with increased morbidity and mortality. Development and implementation of a risk score model for CKD would allow comparison of the risks and benefits of adding potentially nephrotoxic antiretrovirals to a treatment regimen and would identify those at greatest risk of CKD. The aims of this study were to develop a simple, externally validated, and widely applicable long-term risk score model for CKD in HIV-positive individuals that can guide decision making in clinical practice. Methods and Findings A total of 17,954 HIV-positive individuals from the Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) study with >= 3 estimated glomerular filtration rate (eGFR) values after 1 January 2004 were included. Baseline was defined as the first eGFR > 60 ml/min/1.73 m2 after 1 January 2004; individuals with exposure to tenofovir, atazanavir, atazanavir/ritonavir, lopinavir/ritonavir, other boosted protease inhibitors before baseline were excluded. CKD was defined as confirmed (>3 mo apart) eGFR In the D:A:D study, 641 individuals developed CKD during 103,185 person-years of follow-up (PYFU; incidence 6.2/1,000 PYFU, 95% CI 5.7-6.7; median follow-up 6.1 y, range 0.3-9.1 y). Older age, intravenous drug use, hepatitis C coinfection, lower baseline eGFR, female gender, lower CD4 count nadir, hypertension, diabetes, and cardiovascular disease (CVD) predicted CKD. The adjusted incidence rate ratios of these nine categorical variables were scaled and summed to create the risk score. The median risk score at baseline was -2 (interquartile range -4 to 2). There was a 1: 393 chance of developing CKD in the next 5 y in the low risk group (risk score = 5, 505 events), respectively. Number needed to harm (NNTH) at 5 y when starting unboosted atazanavir or lopinavir/ritonavir among those with a low risk score was 1,702 (95% CI 1,166-3,367); NNTH was 202 (95% CI 159-278) and 21 (95% CI 19-23), respectively, for those with a medium and high risk score. NNTH was 739 (95% CI 506-1462), 88 (95% CI 69-121), and 9 (95% CI 8-10) for those with a low, medium, and high risk score, respectively, starting tenofovir, atazanavir/ritonavir, or another boosted protease inhibitor. The Royal Free Hospital Clinic Cohort included 2,548 individuals, of whom 94 individuals developed CKD (3.7%) during 18,376 PYFU (median follow-up 7.4 y, range 0.3-12.7 y). Of 2,013 individuals included from the SMART/ESPRIT control arms, 32 individuals developed CKD (1.6%) during 8,452 PYFU (median follow-up 4.1 y, range 0.6-8.1 y). External validation showed that the risk score predicted well in these cohorts. Limitations of this study included limited data on race and no information on proteinuria. Conclusions Both traditional and HIV-related risk factors were predictive of CKD. These factors were used to develop a risk score for CKD in HIV infection, externally validated, that has direct clinical relevance for patients and clinicians to weigh the benefits of certain antiretrovirals against the risk of CKD and to identify those at greatest risk of CKD.Peer reviewe

Sensitivity of space and time on scanning LiDAR data correlation and the implications on synchronisation of bi-static systems

When possible, running a cross comparison between two or more instruments that are out on the field is an important check for accuracy, consistency and reliability of the instruments in question. As part of the Carbon Trust OWA Offshore wakes campaign, two scanning LiDAR systems were deployed to give near full coverage of the host offshore wind farm. As part of the programme, periodic checks were performed to give confidence on how each system was performing, and that system output remained consistent. The LiDARs were several kilometres apart and the scan patterns were not synchronised temporally or spatially. It was, however, possible to pick out data points from the two LiDAR data sets that could be used for such a cross comparison based on their spatial and temporal separation. The line of sight velocities were compared for certain beam angle scenarios. The process and results of the correlations and their sensitivity are presented, with implications as to the accuracy needed when looking to implement bi-static systems, using more than one system to scan the same volume of space

Tiger Beetles deserve separate family status in suborder Adephaga (Coleoptera, Cicindelidae)

Following a second author's recent paper (Cassola, 2001), the family status of the tiger beetles within the Adephagan Coleoptera is fully confirmed based also on preimaginal characters.Confirmation du statut de famille pour les Cicindélides (Coleóptera, Cicindelidae). Faisant suite à un récent travail du second auteur (Cassola, 2001), le statut de famille à part entière des Cicindélides parmi les Adéphagiens (Coleoptera) est tout à fait confirmé sur la base aussi des caractères préimaginaux.Putchkov Alexander, Cassola Fabio. Tiger Beetles deserve separate family status in suborder Adephaga (Coleoptera, Cicindelidae). In: Bulletin de la Société entomologique de France, volume 110 (3), août 2005. pp. 281-293

Variations in offshore wind turbine wake profiles with different inflow conditions of non-wake-affected upstream wind

The wind energy industry has recently started to look in more depth at wind turbine wakes. Studies of wake behaviour have been carried out by analysing data measured from within this turbulent wind flow downstream of a turbine. As part of The Carbon Trust’s Offshore Wind Accelerator (OWA) offshore wakes campaign, four nacelle mounted LiDARs were deployed on two neighbouring wind turbines located at the edge of an offshore wind farm in Denmark. The LiDARs were paired in a forward and backward facing configuration on each nacelle. This particular layout for the LiDARs allowed wind conditions to be recorded for each wind turbine at several distances from them from both upstream and downstream directions. Many variations of inflow wind conditions coming onto the turbines at hub height were captured by the forward facing LiDARs and the respectively different wake profiles were recorded by the aft LiDARs. Analysis was carried out on the LiDAR data for each wind turbine for the case when the upstream wind direction was from the free stream sector, that is, the sector relative to the turbine in which upstream wind was outside the wake of any other turbine in the farm. Different wind deficit profiles were characterised for the different inflow conditions such as wind speed and turbulence intensity, and any relationships between them were reported