Nutrient Loss Rates in Relation to Transport Time Scales in a Large Shallow Lake (Lake St. Clair, USA—Canada): Insights From a Three‐Dimensional Model

A nutrient mass balance and a three‐dimensional, coupled hydrodynamic‐ecological model, calibrated and validated for Lake St. Clair with observations from 2009 and 2010, were integrated to estimate monthly lake‐scale nutrient loss rates, and to calculate 3 monthly transport time scales: flushing time, water age, and water residence time. While nutrient loss rates had statistically significant relationships with all transport time scale measures, water age had the strongest explanatory power, with water age and nutrient loss rates both smaller in spring and fall and larger in summer. We show that Lake St. Clair is seasonally divided into two discrete regions of contrasting water age and productivity. The north‐western region is dominated by oligotrophic waters from the St. Clair River, and south‐eastern region is dominated by the nutrient enriched, more productive waters from the Thames‐Sydenham River complex. The spatial and temporal variations in local transport scales and nutrient loss rates, coupled with strong seasonal variations in discharge and nutrient loads from the major tributaries, suggest the need for different load reduction strategies for different tributaries.Key PointsWe applied a three‐dimensional ecosystem model to simulate physical, chemical, and biological dynamics in a large shallow lakeWe found that spatially dependent water residence time represents lake flushing better than traditional flushing timeWater age influences the spatial and temporal distribution of nutrient retention, primary production, and algal biomass distributionPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145320/1/wrcr23330.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145320/2/wrcr23330_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145320/3/wrcr23330-sup-0001-2017WR021876-s01.pd

Bremsstrahlung emission during α\alpha-decay of 226Ra^{226}{\rm Ra}

We obtained the spectrum of probability of the bremsstrahlung emission accompanying the $\alpha$-decay of $^{226}{\rm Ra}$ (E$_{\alpha}$=4.8 MeV) by measuring the $\alpha$-$\gamma$ coincidences and using the model presented in our previous study on the $\alpha-$decay of $^{214}{\rm Po}$ (E$_{\alpha}$=7.7 MeV). We compare the experimental data with the quantum mechanical calculation and find a good agreement between theory and experiment. We discuss the differences between the photon spectra connected with the $\alpha$-decay of the $^{226}{\rm Ra}$ and $^{214}{\rm Po}$ nuclei. For the two mentioned nuclei we analyze the bremsstrahlung emission contributions from the tunneling and external regions of the nucleus barrier into the total spectrum, and we find the destructive interference between these contributions. We also find that the emission of photons during tunneling of the $\alpha$-particle gives an important contribution to the bremsstrahlung spectrum in the whole E$_{\gamma}$ energy range of the studied $^{226}$Ra nucleus

Caracteristica imunităţii humorale şi microbiocenoza intestinală la bolnavii cu tuberculoză pulmonară

A fost apreciat statutul imun humoral la 44 de pacienţi cu tuberculoză pulmonară, care au fost repartizaţi în 3 grupe: disbioză de gradu 1 – 13 bolnavi; gradul 2 -11 bolnavi şi gradul 3 -20 bolnavi. La toţi pacienţii a fost studiat subclasele de imunoglobuline A, M, G, nivelul complexelor imune circulante, concentraţia ALAT şi ASAT, indexul intoxicaţiei Kalf-Kalif şi indexul leucocitar al reactivităţii imune. S-a demonstrat că în dependenţă de gradul disfuncţiei microbiocenozei intestinale se agravează indicii statutului imun umoral, fermenţii ALAT şi ASAT. La bolnavii cu disfuncţie intestinală de gradul 3 s-a depistat cele mai vădite dereglări ale statutului imun şi funcţiei de detoxicare ale fi catului

Electrode Polarization Effects in Broadband Dielectric Spectroscopy

In the present work, we provide broadband dielectric spectra showing strong electrode polarization effects for various materials, belonging to very different material classes. This includes both ionic and electronic conductors as, e.g., salt solutions, ionic liquids, human blood, and colossal-dielectric-constant materials. These data are intended to provide a broad data base enabling a critical test of the validity of phenomenological and microscopic models for electrode polarization. In the present work, the results are analyzed using a simple phenomenological equivalent-circuit description, involving a distributed parallel RC circuit element for the modeling of the weakly conducting regions close to the electrodes. Excellent fits of the experimental data are achieved in this way, demonstrating the universal applicability of this approach. In the investigated ionically conducting materials, we find the universal appearance of a second dispersion region due to electrode polarization, which is only revealed if measuring down to sufficiently low frequencies. This indicates the presence of a second charge-transport process in ionic conductors with blocking electrodes.Comment: 9 pages, 6 figures, experimental data are provided in electronic form (see "Data Conservancy"

Relationships between mammographic density, tissue microvessel density, and breast biopsy diagnosis

Association between microvessel density (MVD) and tumor characteristics among breast cancer cases (n = 44). (DOC 54 kb

Perceptual and technical barriers in sharing and formatting metadata accompanying omics studies

Metadata, often termed "data about data," is crucial for organizing, understanding, and managing vast omics datasets. It aids in efficient data discovery, integration, and interpretation, enabling users to access, comprehend, and utilize data effectively. Its significance spans the domains of scientific research, facilitating data reproducibility, reusability, and secondary analysis. However, numerous perceptual and technical barriers hinder the sharing of metadata among researchers. These barriers compromise the reliability of research results and hinder integrative meta-analyses of omics studies . This study highlights the key barriers to metadata sharing, including the lack of uniform standards, privacy and legal concerns, limitations in study design, limited incentives, inadequate infrastructure, and the dearth of well-trained personnel for metadata management and reuse. Proposed solutions include emphasizing the promotion of standardization, educational efforts, the role of journals and funding agencies, incentives and rewards, and the improvement of infrastructure. More accurate, reliable, and impactful research outcomes are achievable if the scientific community addresses these barriers, facilitating more accurate, reliable, and impactful research outcomes

Conductivity study of Zeolitic Imidazolate Frameworks, Tetrabutylammonium hydroxide doped with Zeolitic Imidazolate Frameworks, and mixed matrix membranes of Polyetherimide/Tetrabutylammonium hydroxide doped with Zeolitic Imidazolate Frameworks for proton conducting applications

[EN] ZIF-8 (Z8), ZIF-67 (Z67), and ZMix, a Zn/Co bimetallic zeolitic imidazolate framework (ZIF), were synthesized and doped with tetrabutylammonium hydroxide (ZIFsT). The obtained powders were used as fillers for polyetherimide (PEI) at a concentration of 20 wt %. The presence of the three ZIFsT in the polymeric matrix enhanced proton transport relative to that observed for PEI or ZIFs alone. The real and imaginary parts of the complex conductivity were obtained for each of the six materials, and the temperature and frequency dependence of the real part was analyzed. The results at different temperatures show that the dc-conductivity are about three orders of magnitude higher for the doped ZIFsT materials than for the PEI/ZIFsT membranes. In addition, the conductivity of the PEI/ZIFsT membranes increases five or six times when the temperature is changed from 25 °C to 55 °C. For these materials, the conductivity measurements have a linear dependency with frequency, which allowed for the creation of a master curve. It was also found that the PEI/ZMixT membrane activation energy is four times smaller than that of PEI/Z8T membranes and five times smaller than that of PEI/Z67T. Similarly, the real and imaginary parts of the complex dielectric constant were obtained, and the tan ¿ was evaluated. Using this value, the diffusion coefficient and the charge carrier density were obtained. A discussion of the proton transport mechanism through the membrane is given, and a comparison of this work with those on similar electrolyte membranes is included.This research has been supported by the ENE/2015-69203-R project, granted by the Ministerio de Economia y Competitividad (MINECO), Spain, and grants from National Mexican Council for Science and Technology for the scholarships of Ph.D. No. 356825 and mixed scholarship 2015 - MZO2016-mobility in the foreigner granted to Jesus Vega Moreno registered scholarship holder number 256015. Thanks to the CONACYT Program for the fellowship at the Universidad Politecnica de Valencia (UPV) and Universitat Jaume I that PhD student Jesus Vega used to carry out the experimental studies of this work. DGAPA-PAPIIT IG-100315.Vega, J.; Andrio, A.; Lemus, AA.; Del Castillo, LF.; Compañ Moreno, V. (2017). Conductivity study of Zeolitic Imidazolate Frameworks, Tetrabutylammonium hydroxide doped with Zeolitic Imidazolate Frameworks, and mixed matrix membranes of Polyetherimide/Tetrabutylammonium hydroxide doped with Zeolitic Imidazolate Frameworks for proton conducting applications. Electrochimica Acta. 258:153-166. https://doi.org/10.1016/j.electacta.2017.10.095S15316625