Observations, mixed-layer theory and the Dutch Large-Eddy Simulation model (DALES) are used to analyze the dynamics of the boundary layer during an intensive operational period (1 July 2011) of the ...Boundary Layer Late Afternoon and Sunset Turbulence campaign. Continuous measurements made by remote sensing and in situ instruments in combination with radio soundings, and measurements done by remotely piloted aircraft systems and two manned aircrafts probed the vertical structure and the temporal evolution of the boundary layer during the campaign. The initial vertical profiles of potential temperature, specific humidity and wind, and the temporal evolution of the surface heat and moisture fluxes prescribed in the models runs are inspired by some of these observations. The research focuses on the role played by the residual layer during the morning transition and by the large-scale subsidence on the evolution of the boundary layer. By using DALES, we show the importance of the dynamics of the boundary layer during the previous night in the development of the boundary layer at the morning. DALES numerical experiments including the residual layer are capable of modeling the observed sudden increase of the boundary-layer depth during the morning transition and the subsequent evolution of the boundary layer. These simulations show a large increase of the entrainment buoyancy flux when the residual layer is incorporated into the mixed layer. We also examine how the inclusion of the residual layer above a shallow convective boundary layer modifies the turbulent kinetic energy budget. Large-scale subsidence mainly acts when the boundary layer is fully developed, and, for the studied day, it is necessary to be considered to reproduce the afternoon observations. Finally, we also investigate how carbon dioxide (CO2) mixing ratio stored the previous night in the residual layer plays a fundamental role in the evolution of the CO2 mixing ratio during the following day.
We study the influence of the large-scale atmospheric contribution to the dynamics of the convective boundary layer (CBL) in a situation observed during the Boundary Layer Late Afternoon and Sunset ...Turbulence (BLLAST) field campaign. We employ two modeling approaches, the mixed-layer theory and large-eddy simulation (LES), with a complete data set of surface and upper-air atmospheric observations, to quantify the contributions of the advection of heat and moisture, and subsidence. We find that by only taking surface and entrainment fluxes into account, the boundary-layer height is overestimated by 70%. Constrained by surface and upper-air observations, we infer the large-scale vertical motions and horizontal advection of heat and moisture. Our findings show that subsidence has a clear diurnal pattern. Supported by the presence of a nearby mountain range, this pattern suggests that not only synoptic scales exert their influence on the boundary layer, but also mesoscale circulations. LES results show a satisfactory correspondence of the vertical structure of turbulent variables with observations. We also find that when large-scale advection and subsidence are included in the simulation, the values for turbulent kinetic energy are lower than without these large-scale forcings. We conclude that the prototypical CBL is a valid representation of the boundary-layer dynamics near regions characterized by complex topography and small-scale surface heterogeneity, provided that surface- and large-scale forcings are representative for the local boundary layer.
Objective
Evaluation of the efficacy of a wireless high‐frequency stimulator placed over selected DRG of exiting nerve roots for the treatment of chronic low back pain.
Design
Feasibility.
Subjects
...Six subjects with chronic, intractable back pain refractory to standard medical treatment.
Methods
Four stimulators (Freedom‐4A) provided by Stimwave Technologies, were implanted over the DRG exiting nerve roots, bilaterally at both the T9 and L2 vertebral levels. Subjects were asked to evaluate stimulation independently with the devices turned on at T9 and subsequently L2 for each of 2 weeks. Subjects were then monitored for 8 weeks with the preferred stimulator. Pain reduction with the Visual Analog Scale (VAS), functionality with the Oswestry Disability Index (ODI), Patient Global Impression of Change (PGIC) and medication usage were evaluated.
Results
Four subjects preferred T9 stimulation with only one subject preferring stimulation at L2. One subject dropped out of the study before conclusion of the 4‐week evaluation and is not included in this report. Average pain levels (n = 5) at 12‐week post‐implantation decreased with 61% for back pain and 56% for leg pain with a significant reduction in pain medication, including a 100% reduction in opioid pain medications. The average reduction in disability was 12%. Subjects reported an average impression of change of 6 (1 = no change, 7 = great deal better).
Conclusions
Wireless high‐frequency stimulation of the DRG is a viable option to treat chronic low back pain. Preliminary results show a subject preference for stimulation at the T9 vertebral level.
Due to the major role of the sun in heating the earth's surface, the atmospheric planetary boundary layer over land is inherently marked by a diurnal cycle. The afternoon transition, the period of ...the day that connects the daytime dry convective boundary layer to the night-time stable boundary layer, still has a number of unanswered scientific questions. This phase of the diurnal cycle is challenging from both modelling and observational perspectives: it is transitory, most of the forcings are small or null and the turbulence regime changes from fully convective, close to homogeneous and isotropic, toward a more heterogeneous and intermittent state. These issues motivated the BLLAST (Boundary-Layer Late Afternoon and Sunset Turbulence) field campaign that was conducted from 14 June to 8 July 2011 in southern France, in an area of complex and heterogeneous terrain. A wide range of instrumented platforms including full-size aircraft, remotely piloted aircraft systems, remote-sensing instruments, radiosoundings, tethered balloons, surface flux stations and various meteorological towers were deployed over different surface types. The boundary layer, from the earth's surface to the free troposphere, was probed during the entire day, with a focus and intense observation periods that were conducted from midday until sunset. The BLLAST field campaign also provided an opportunity to test innovative measurement systems, such as new miniaturized sensors, and a new technique for frequent radiosoundings of the low troposphere. Twelve fair weather days displaying various meteorological conditions were extensively documented during the field experiment. The boundary-layer growth varied from one day to another depending on many contributions including stability, advection, subsidence, the state of the previous day's residual layer, as well as local, meso- or synoptic scale conditions. Ground-based measurements combined with tethered-balloon and airborne observations captured the turbulence decay from the surface throughout the whole boundary layer and documented the evolution of the turbulence characteristic length scales during the transition period. Closely integrated with the field experiment, numerical studies are now underway with a complete hierarchy of models to support the data interpretation and improve the model representations.
In spinal cord stimulation (SCS) mainly 2 distinctive implantation techniques can be recognized: the percutaneous and surgical technique.
A puncture is made with a blunt 14 gauge Tuohy needle. Once ...inside the epidural space the guide wire needs to be advanced in the epidural space, then the Tuohy needle is removed. The Epiducer is advanced under the guidance of lateral fluoroscopy, to confirm epidural entry. The S-series electrode is introduced through the sheet in the epidural space.
We present a novel technique to introduce small profile paddle leads (S-Series™: St. Jude Medical - Neuromodulation Division, Plano, TX) in the epidural space via a percutaneous approach using the Epiducer™ (St. Jude Medical - Neuromodulation Division, Plano, TX) lead delivery system.
During spinal cord stimulation there is sometimes a need to replace defective leads. Percutaneous lead replacement by recannulating the epidural space and "steering" the new lead to the prior ...location is sometimes very difficult, resulting in diminished analgesia. Since fibrous deposits are known to form around epidural catheters and epidural obstructions have been noted with other techniques, we have inserted the new lead through the well-dissected opening in the interspinal ligament. We will report the results of our case series.
In 11 patients with lead malfunction we reinserted a new electrode into the epidural space by first withdrawing the lead with one hand and inserting the new one through the interspinal ligament with the other. In using this method, we found we could position the new electrode almost identically to the first. In only 3 patients did we experience difficulty in identifying the opening for the insertion. In the successfully cannulated patients identical stimulation parameters and paresthesia areas were obtained. By experimentally injecting contrast dye through an epidural catheter inserted into the interspinal opening and epidural pathway, we could visualize a thin dense line representing the fibrous sheath.
Foreign bodies in the epidural space lead to fibrous deposits. Spinal cord stimulation, when those deposits form a sheath, the sheath is useful for lead revision. The procedure, if meticulously performed, has a high success rate.
In different species, embryonic aneuploidies and genome-wide errors are a major cause of developmental failure. The increasing number of equine embryos being produced worldwide provides the ...opportunity to characterize and rank or select embryos based on their genetic profile prior to transfer. Here, we explored the possibility of generic, genome-wide preimplantation genetic testing concurrently for aneuploidies (PGT-A) and monogenic (PGT-M) traits and diseases in the horse, meanwhile assessing the incidence and spectrum of chromosomal and genome-wide errors in in vitro-produced equine embryos. To this end, over 70,000 single nucleotide polymorphism (SNP) positions were genotyped in 14 trophectoderm biopsies and corresponding biopsied blastocysts, and in 26 individual blastomeres from six arrested cleavage-stage embryos. Subsequently, concurrent genome-wide copy number detection and haplotyping by haplarithmisis was performed and the presence of aneuploidies and genome-wide errors and the inherited parental haplotypes for four common disease-associated genes with high carrier frequency in different horse breeds (GBE1, PLOD1, B3GALNT2, MUTYH), and for one color coat-associated gene (STX17) were compared in biopsy-blastocyst combinations. The euploid (n = 12) or fully aneuploid (n = 2) state and the inherited parental haplotypes for 42/45 loci of interest of the biopsied blastocysts were predicted by the biopsy samples in all successfully analyzed biopsy-blastocyst combinations (n = 9). Two biopsies showed a loss of maternal chromosome 28 and 31, respectively, which were confirmed in the corresponding blastocysts. In one of those biopsies, additional complex aneuploidies not present in the blastocyst were found. Five out of six arrested embryos contained chromosomal and/or genome-wide errors in most of their blastomeres, demonstrating their contribution to equine embryonic arrest in vitro. The application of the described PGT strategy would allow to select equine embryos devoid of genetic errors and pathogenetic variants, and with the variants of interest, which will improve foaling rate and horse quality. We believe this approach will be a gamechanger in horse breeding.
We investigate ionospheric perturbations associated with traveling ionospheric disturbance (TID) during the geomagnetic storm on Memorial Day weekend (28 May) 2017. Results show the presence of both ...equatorward propagating large‐scale TIDs (LSTIDs) and poleward propagating medium‐scale TIDs. Equatorward moving TIDs are connected with enhanced auroral activity owing to geomagnetic storm conditions, while poleward TIDs are believed to be induced by local atmospheric gravity wave sources originating from convection activities near the West Coast of North America. Measurements from magnetometers located in the west, central, and east regions of North America are used to evaluate energy inputs from the auroral belt, and these observations confirm that equatorward LSTIDs are due to geomagnetic disturbance. The observed LSTID waves were characterized by some uncommon features, such as horizontal wavefront stretching from coast to coast, aligned in the NW to SE direction, and propagating to the southwest (equatorward) direction during the storm main phase period. In contrast, during the recovery phase and on other experimental control days, the observed medium‐scale TIDs were characterized with relatively smaller wavelengths aligned in the NW to SE direction and propagate primarily in the northeast (poleward) direction. Our results also reveal that LSTID waves appear to travel faster in the central continental region compared to LSTIDs in the western and eastern regions.
Plain Language Summary
This study reveals the coupling of magnetosphere and ionosphere system as well as the interaction between the lower and upper atmosphere. Using the Global Navigation Satellite Systems (GNSS) receivers widely distributed over United States, networks of magnetometers over North America, and satellite measurements from the National Oceanic and Atmospheric Administration‐Geostationary Operational Environmental Satellite (NOAA‐GOES) and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) missions, we investigated the traveling ionospheric disturbance (TID) characteristics during the 28 May 2017 Memorial Day weekend geomagnetic storm and some quiet geomagnetic periods. Our results show equatorward large‐scale TID owning to the 2017 Memorial Day weekend geomagnetic storm and poleward medium‐scale TID propagation owning to atmospheric convection activity over the continental United States.
Key Points
Coupling between magnetosphere and ionosphere resulting from the 2017 Memorial Day weekend geomagnetic storm
Interactions between lower and upper atmosphere owning to tropospheric weather convection activity
Equatorward and poleward traveling ionosperic disturbances (TIDs) over North America during quiet and disturbed periods
Homeostatic regulation protects organisms against hazardous physiological changes. However, such regulation is limited in certain organs and associated biological processes. For example, the heart ...fails to self-restore its normal electrical activity once disturbed, as with sustained arrhythmias. Here we present proof-of-concept of a biological self-restoring system that allows automatic detection and correction of such abnormal excitation rhythms. For the heart, its realization involves the integration of ion channels with newly designed gating properties into cardiomyocytes. This allows cardiac tissue to i) discriminate between normal rhythm and arrhythmia based on frequency-dependent gating and ii) generate an ionic current for termination of the detected arrhythmia. We show in silico, that for both human atrial and ventricular arrhythmias, activation of these channels leads to rapid and repeated restoration of normal excitation rhythm. Experimental validation is provided by injecting the designed channel current for arrhythmia termination in human atrial myocytes using dynamic clamp.
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