An Inverse Modeling Approach to Estimating Phytoplankton Pigment Concentrations from Phytoplankton Absorption Spectra

Phytoplankton absorption spectra and High-Performance Liquid Chromatography (HPLC) pigment observations from the Eastern U.S. and global observations from NASA's SeaBASS archive are used in a linear inverse calculation to extract pigment-specific absorption spectra. Using these pigment-specific absorption spectra to reconstruct the phytoplankton absorption spectra results in high correlations at all visible wavelengths (r(sup 2) from 0.83 to 0.98), and linear regressions (slopes ranging from 0.8 to 1.1). Higher correlations (r(sup 2) from 0.75 to 1.00) are obtained in the visible portion of the spectra when the total phytoplankton absorption spectra are unpackaged by multiplying the entire spectra by a factor that sets the total absorption at 675 nm to that expected from absorption spectra reconstruction using measured pigment concentrations and laboratory-derived pigment-specific absorption spectra. The derived pigment-specific absorption spectra were further used with the total phytoplankton absorption spectra in a second linear inverse calculation to estimate the various phytoplankton HPLC pigments. A comparison between the estimated and measured pigment concentrations for the 18 pigment fields showed good correlations (r(sup 2) greater than 0.5) for 7 pigments and very good correlations (r(sup 2) greater than 0.7) for chlorophyll a and fucoxanthin. Higher correlations result when the analysis is carried out at more local geographic scales. The ability to estimate phytoplankton pigments using pigment-specific absorption spectra is critical for using hyperspectral inverse models to retrieve phytoplankton pigment concentrations and other Inherent Optical Properties (IOPs) from passive remote sensing observations

Generation and modeling of gaseous plasmas using microwave (MW) power

[EN] In contrast to RF produced plasmas, in the case of microwave plasmas the energy from the electromagnetic (EM) field is communicated only to electrons since ions, being a few thousand times much heavier than electrons, cannot respond to the periodic changes in the direction of the E-field of microwaves (typical frequency range 100 MHz-300 GHz) and therefore cannot gain energy in the EM field. The energy of electrons is essentially transferred to heavy particles either through numerous enough collisions during the E-field period (high enough gas pressures) or through electron-cyclotron resonance (pressures below mTorr) sustaining in this way the gas discharge. This had led to introduce the concept of power absorbed per electron qA and power loss on a per electron basis qL [1]. Under steady-state conditions and when the plasma volume (the volume in which plasma particles recombine and, thus, power is lost) is equal to the volume in which power is absorbed from the MW field, we have the power balance qA = qL, which can be shown to be much informative than the usual global power balance. qA is defined as where n is the electron collision frequency for momentum transfer, w, the wave angular frequency, e/me, the electron charge to mass ratio, and , the mean squared value of the EM E-field. The value of qA (absorbed power) is shown to adjust so as to compensate exactly for qL (power losses), which is thus the dominant power parameter; as a result, the intensity of the maintenance E-field sustaining the discharge comes out as an internal parameter, i.e., it is operator-independent, in contrast to what is generally believed whatever the kind of E-field sustained discharges. Other related features are: i) whenever this can be achieved, the smaller the volume in which power is absorbed with respect to the volume in which it is spent, the higher the intensity of the maintenance E-field: this leads to higher atomic (molecular) excitation rates inside than outside the absorption region (such is the case in micro-discharges); ii) an interesting fact as far as understanding RF and MW discharge properties is concerned is that the value of qL decreases with increasing frequency from the RF domain to that of MWs; iii) similarity laws, initially derived with DC discharges, are generalized to include RF and microwave discharges. For example, qA/p as a function of pR (p is gas pressure and R discharge-tube inner radius) replaces advantageously the widely used E/p vs. pR similarity law since qA is more easily measured than E2 and further it avoids considering the latter as an external parameter, etc.; iv) using the power per electron balance, it can be proved that the EM E-field intensity under electron cyclotron resonance (ECR) condition passes through a minimum, not a maximum, contrary to what is generally claimed; v) the E-field intensity under pulsed regime can be maximized under short enough pulse length and long enough off-time in between.Moisan, M.; Nowakowska, H. (2019). Generation and modeling of gaseous plasmas using microwave (MW) power. En AMPERE 2019. 17th International Conference on Microwave and High Frequency Heating. Editorial Universitat Politècnica de València. 27-34. https://doi.org/10.4995/AMPERE2019.2019.9989OCS273

Mortality in kittens is associated with a shift in ileum mucosa-associated enteroccoci from E. hirae to biofilm-forming E. faecalis and adherent E. coli

Approximately ~15% of foster kittens die before 8-wks of age with most of these kittens demonstrating clinical signs or post-mortem evidence of enteritis. While a specific cause of enteritis is not determined in most cases; these kittens are often empirically administered probiotics that contain enterococci. The enterococci are members of the commensal intestinal microbiota but can also function as opportunistic pathogens. Given the complicated role of enterococci in health and disease, it would be valuable to better understand what constitutes a “healthy” enterococcal community in these kittens and how this microbiota is impacted by severe illness. In this study, we characterize the ileum mucosa-associated enterococcal community of 50 apparently healthy and 50 terminally ill foster kittens. In healthy kittens, E. hirae was the most common species of ileum mucosa-associated enterococci and was often observed to adhere extensively to the small intestinal epithelium. These E. hirae isolates generally lacked virulence traits. In contrast, non-E. hirae enterococci, notably E. faecalis, were more commonly isolated from the ileum mucosa of kittens with terminal illness. Isolates of E. faecalis had numerous virulence traits and multiple antimicrobial resistance. Moreover, attachment of E. coli to the intestinal epithelium was significantly associated with terminal illness and was not observed in any kitten with adherent E. hirae. These findings identify a significant difference in species of enterococci cultured from the ileum mucosa of kittens with terminal illness compared to healthy kittens. In contrast to prior case studies that associate enteroadherent E. hirae with diarrhea in young animals, these controlled studies identified E. hirae as more often isolated from healthy kittens and adherence of E. hirae as more common and extensive in healthy compared to sick kittens

First neutron spectroscopy measurements in the ASDEX Upgrade tokamak

Abstract: A compact neutron spectrometer based on the liquid scintil-lator BC501A has been installed on the ASDEX Upgrade tokamak. The aim is to measure neutron energy distribution functions as footprints of fast ions distribution functions, generated mainly via Neutral Beam Injection (NBI) in present day tokamaks. A flexible and fast software has been developed to perform digital pulse shape separation and to evaluate pulse height spectra. First measurements of count rates and pulse height spectra show a good sig-nal to noise ratio for integration times comparable to the NBI slowing down time and to the energy confinement time. Due to the perpendicular line of sight, D-d fusion with perpendicular NBI is detected more efficiently and the line broadening of the 2.45 MeV neutrons is higher. Ion Cyclotron Reso-nance Heating (ICRH) combined to NBI exhibits a synergy effect, with count rates higher than the sum of the counts due to NBI and ICRH separately. Although the collimator is designed to screen gammas as much as possible, some qualitative gamma analysis is also possible, providing information in case of runaway electrons during disruptions. The experimental campaign for the characterisation of the system (detector + acquisition system) is complete and the determination of the response function is in progress.

Impact of a Community Pharmacist-Delivered Information Program on the Follow-up of Type-2 Diabetic Patients: A Cluster Randomized Controlled Study.

Low-quality communication between patients and care providers and limited patient knowledge of the disease and the therapy are important factors associated with poor glycemic control in patients with type 2 diabetes. We conducted a multicenter study to determine whether structured and tailored information delivered by pharmacists to type 2 diabetic patients could improve patient treatment adherence, hemoglobin A1c (HbA1c) levels and knowledge about diabetes. One hundred seventy-four pharmacies were randomized to deliver an educational program on diet, drug treatment, disease and complications during three 30-min interviews over a 6-month period, or to provide no intervention, to type 2 diabetic patients treated with oral antidiabetic agents. Medication adherence was assessed by measuring the medication possession ratio and diabetes control by collecting HbA1c values. Levels of patient treatment self-management and disease knowledge were assessed using self-questionnaires. Three hundred seventy-seven patients were analyzed. The medication possession ratio, already very high at baseline in the intervention (94.8%) and control (92.3%) groups, did not vary significantly after 6 months with no difference between the two groups. Significant decreases in HbA1c were observed in both groups at 6 months (p < 0.001) and 12 months (p < 0.01), with significantly greater changes from baseline in the intervention group than in the control group at 6 months (- 0.5% vs. - 0.2%, p = 0.0047) and 12 months (- 0.6% vs. - 0.2%, p = 0.0057). Patients in the intervention group showed greater improvement in their ability to self-manage treatment (+ 4.86 vs. + 1.58, p = 0.0014) and in the extent of their knowledge about diabetes (+ 0.6 vs. + 0.2, p < 0.01) at 6 months versus baseline compared with the control group. Tailored information provided by the pharmacist to patients with type 2 diabetes did not significantly improve the already high adherence rates, but was associated with a significant decrease in HbA1c and an improvement of patient knowledge about diabetes. ISRCTN33776525. MSD France

Tuning a Schottky barrier in a photoexcited topological insulator with transient Dirac cone electron-hole asymmetry

The advent of Dirac materials has made it possible to realize two dimensional gases of relativistic fermions with unprecedented transport properties in condensed matter. Their photoconductive control with ultrafast light pulses is opening new perspectives for the transmission of current and information. Here we show that the interplay of surface and bulk transient carrier dynamics in a photoexcited topological insulator can control an essential parameter for photoconductivity - the balance between excess electrons and holes in the Dirac cone. This can result in a strongly out of equilibrium gas of hot relativistic fermions, characterized by a surprisingly long lifetime of more than 50 ps, and a simultaneous transient shift of chemical potential by as much as 100 meV. The unique properties of this transient Dirac cone make it possible to tune with ultrafast light pulses a relativistic nanoscale Schottky barrier, in a way that is impossible with conventional optoelectronic materials.Comment: Nature Communications, in press (12 pages, 6 figures

Mold Filling Simulation of Semi-Solid Magnesium Alloys

Peer reviewed: YesNRC publication: Ye