Absolute Density Research Articles

Polarization Resistance of Ceria-Containing Fuel Electrodes in Solid Oxide Cells Studied By Impedance and DRT Analysis

Introduction Solid oxide electrolysis cell (SOEC), which enables steam electrolysis by reversely operating solid oxide fuel cell (SOFC), is capable of highly efficient hydrogen production. Whilst SOFC and SOEC are using similar materials and cell structures, electrode reactions in SOEC operation have to be studied in more details. In our previous study [1], Ni-ScSZ cermet, widely used as SOFC fuel electrodes, exhibited a tendency where electrode resistance increases at a low absolute current density in SOEC operation, while Ni-GDC co-impregnated cells fabricated by the impregnation method exhibited sufficient performance in a wide current density range. Here in this study, various model fuel electrode materials were evaluated and compared in a wide current density range in the SOFC and SOEC modes under the same measurement conditions. Electrode reactions are evaluated through measurements of electrochemical impedance spectra (EIS) and subsequent analysis of distribution of relaxation times (DRT). Experimental Three types of cells with different fuel electrodes were prepared: Ni-ScSZ cermet fuel electrode; Ni-GDC cermet fuel electrode; and Ni-GDC co-impregnated fuel electrode. The Ni-GDC cermet fuel electrodes were fabricated using gadolinia-doped ceria (GDC), widely known as a mixed ionic electronic conductor, besides a pure ionic conductor ScSZ. The Ni-GDC co-impregnated cell was fabricated by preparing a composite electrode backbone of GDC and La-doped SrTiO3 (LST), followed by impregnation of the catalyst particles, Ni and GDC. La-Sr-Ti oxides are known to exhibit sufficient stability in both oxidizing and reducing atmospheres [2, 3]. Moreover, co-impregnated fuel electrodes have shown high tolerance against highly-humidified hydrogen fuel and redox durability [4].Electrode resistances were separated into the ohmic resistance and the nonohmic polarization resistance through electrochemical impedance spectroscopy. Impedance measurements were made by using an impedance analyzer (1255WB, Solartron, UK) in a frequency range between 0.1 Hz and 1 MHz. The fuel, 50%-humidified H2, was supplied to the fuel electrode. The operating temperature was 800 °C. To characterize the electrode processes in both SOFC and SOEC modes, impedance measurements were performed by applying stepwise changes in current density up to ±1.2 A cm-2, for every 0.2 A cm-2. The DRT analysis of the EIS data was performed using a numerical calculation program based on Tikhonov regularization (Z-Assist, Toyo Corporation, Japan) to separate electrochemical processes involved in the electrode reactions. Results and discussion The polarization resistances obtained by the EIS measurements are shown in Fig. 1. The Ni-ScSZ cermet fuel electrode (Fig. 1 (a)) exhibited unique polarization resistance in the SOEC mode. With increasing the absolute value of current density in the SOEC mode, polarization resistance increased significantly at first, reaching a maximum value at -0.4 A cm-2, then decreased. In contrast, for the Ni-GDC cermet fuel electrode (Fig. 1 (b)), polarization resistance increased only slightly with increasing current density in the SOEC mode, and overall polarization resistance remained low. This tendency was also seen for the Ni-GDC co-impregnated fuel electrode (Fig. 1 (c)), where such increase in polarization resistance was further suppressed.Such increase and decrease in polarization resistance observed for the Ni-ScSZ cermet have to be explained by different mechanisms (at least two opposite factors). One possible explanation could be that the reduced and recovered catalytic activity due to e.g. oxidation and reduction of the Ni catalyst surface. The presence of GDC in the fuel electrode has a positive effect reducing the polarization resistance in the SOEC mode. The electrode reaction area may be extended beyond the Ni surface and/or the triple phase boundaries. Furthermore, the Ce ion in ceria undergoes a valence change, which may promote flexible surface exchange reactions, and surface reactions on the Ni catalysts. For the SOEC operation, it will be desirable to clarify the effects of GDC in the r-SOC electrode reactions. Acknowledgments A part of this study was supported by “Research and Development Program for Promoting Innovative Clean Energy Technologies Through International Collaboration” of the New Energy and Industrial Technology Development Organization (NEDO) (Contract No.20001460-0). Collaborative support by Prof. H. L. Tuller, Prof. B. Yildiz, and Prof. J. L. M. Rupp at Massachusetts Institute of Technology (MIT) is gratefully acknowledged. References N. Endo, T. Fukumoto, R. Ushijima, K. Natsukoshi, Y. Tachikawa, J. Matsuda, S. Taniguchi, and K. Sasaki, ECS Trans., 103(1), 1981 (2021).Q. Ma and F. Tietz, Solid State Ionics, 225, 108 (2012).G. Chen, H. Kishimoto, K. Yamaji, K. Kuramoto, and T. Horita, J. Electrochem. Soc., 162(3), F223 (2014).S. Futamura, A. Muramoto, Y. Tachikawa, J. Matsuda, S. M. Lyth, Y, Shiratori, S. Taniguchi, and K. Sasaki, Int. J. Hydrogen Energy, 44(16), 8502 (2019). Figure 1

Effect of Habitat Disturbance on the Composition of Soil Nematode Functional Groups Associated with a Tropical Herb: Heliconia collinsiana

Habitat loss affects the nature of biotic interactions in all ecosystems and at all levels of the food web. Nevertheless, little attention has been given to soil nematodes in tropical habitats despite their important role in ecosystem functioning worldwide. Here, we analyzed the influence of anthropogenic habitat disturbance on the absolute and relative density and composition (i.e., trophic guilds) of soil nematode communities associated with the rhizosphere of the tropical herb Heliconia collinsiana in continuous mature forests and human-induced secondary forests. We compared nematode densities based on the following feeding guilds: bacterivores, fungivores, herbivores and predators. Thereafter, we classified herbivorous nematodes into genera and described soil properties in both habitat types including pH, electrical conductivity, and organic matter content. Herbivores were significantly the most abundant feeding guild for both habitats represented by Criconemella spp., Helicotylenchus spp., and Meloidogyne spp., which showed no significant differences in density between habitats. Relative but not absolute nematode density differed between habitats, with fungivore nematodes being significantly lower in secondary forests. No significant differences in soil properties were detected. Overall, our results suggest that forest disturbance affects the nematode community associated with the rhizosphere of H. collinsiana which may affect forest succession and the dynamics of the soil biota. Our study contributes to the understanding of biotic interactions in conserved and disturbed tropical habitats.

Dynamics of He++ Ions at Interplanetary and Earth’s Bow Shocks

Experimental investigations of the fine plasma structure of interplanetary shocks are extremely difficult to conduct due to their small thickness and high speed relative to the spacecraft. We studied the variations in the parameters of twice-ionized helium ions (4He++ ions or α-particles) in the solar wind plasma during the passage of interplanetary shocks and Earth’s bow shock. We used data with high time resolution gathered by the BMSW (Bright Monitor of Solar Wind) instrument installed on the SPEKTR-R satellite, which operated between August 2011 and 2019. The MHD parameters of He++ ions (the bulk velocity Vα, temperature Tα, absolute density Nα, and helium abundance Nα/Np) are analyzed for 20 interplanetary shocks and compared with similar parameters for 25 Earth bow shock crossings. Measurements from the WIND, Cluster, and THEMIS satellites were also analyzed. The correlations in the changes in helium abundance Nα/Np with the parameters βi, θBn, and MMS were investigated. The following correlation between Nα/Np and the angle θBn was found: the lower the value of θBn, the greater the drop in helium abundance (Nα/Np) falls behind the IP shock front. For Earth’s bow shock crossings, we found a significant increase in the helium abundance (Nα/Np) in quasi-perpendicular events.

DENSITY OF NERITIDAE IN THE COASTAL WATERS OF SERI VILLAGE, AMBON CITY

These marine natural resources include various types of fish, molluscs, and crustaceans. Maluku is a waters rich in benthic organisms, the coastal environment of Seri village can be said to be productive which shows various types of resources that can be utilized continuously in the presence of various types of marine organisms or marine biota such as Nerita. This research is a form of scientific contribution to learning marine biology. This research is a descriptive type of research, to describe or describe information about the density of Neritidae in the coastal waters of Seri Village which is made in the form of tables and figures. The results of the calculation of the density of Neritidae in the coastal waters of Desa Seri which were carried out as a whole from 3 transects found 7 species, 1 family, 1 genus and 207 individuals in the phylum Mollusca. By calculating the density on the coast of Seri Village, the values ​​for each species are as follows: Nerita squamulata is 0.001833, Nerita chamaeleon is 0.002167, Nerita maxima is 0.002167, Nerita polita is 0.026333, Nerita albicilla is 0, 0015, Nerita planospira was 0.000333 and Nerita patula was 0.000167 with a total absolute density of 0.0345. according to the density category according to Cox (1967) which explains that 0 = no density, 1-10 = less density, 10-20 = sufficient density and > 20 = very high density, thus it can be concluded that Neritidae in coastal waters of Seri village is no density.

Variations of He++ Ion Parameters at Interplanetary and Earth’s Bow Shock Fronts

Experimental investigations of the fine plasma structure of interplanetary shocks are extremely difficult to conduct due to their small thickness and high speed relative to the spacecraft. We study the variations in the parameters of twice-ionized helium ions (4He++ ions or {\alpha}-particles) in the solar wind plasma during the passage of interplanetary shocks and Earth's bow shock. We use data with high time resolution gathered by the BMSW (Bright Monitor of Solar Wind) instrument installed on the SPEKTR-R satellite, which operated between August 2011 and 2019. The MHD parameters of He++ ions (the bulk velocity Va, temperature Ta, absolute density Na, and helium abundance Na/Np) are analyzed for 20 interplanetary shocks and compared with similar parameters for 25 Earth's bow shock crossings. Measurements from the WIND, Cluster and THEMIS satellites were also analyzed. The correlations in the changes in helium abundance Na/Np with the parameters {\beta}_{i}, {\theta}_{Bn} and M_{ms} were investigated. A correlation between Na/Np and the angle {\theta}_{Bn} was found: the lower the value of {\theta}_{Bn}, the greater the drop in helium abundance Na/Np falls behind the IP shock front. For Earth's bow shock crossings, we found a significant increase in the helium abundance Na/Np in quasi-perpendicular events.

Exact two-component Hamiltonians for relativistic quantum chemistry: Two-electron picture-change corrections made simple.

Based on self-consistent field (SCF) atomic mean-field (amf) quantities, we present two simple yet computationally efficient and numerically accurate matrix-algebraic approaches to correct both scalar-relativistic and spin-orbit two-electron picture-change effects (PCEs) arising within an exact two-component (X2C) Hamiltonian framework. Both approaches, dubbed amfX2C and e(xtended)amfX2C, allow us to uniquely tailor PCE corrections to mean-field models, viz. Hartree-Fock or Kohn-Sham DFT, in the latter case also avoiding the need for a point-wise calculation of exchange-correlation PCE corrections. We assess the numerical performance of these PCE correction models on spinor energies of group 18 (closed-shell) and group 16 (open-shell) diatomic molecules, achieving a consistent ≈10-5 Hartree accuracy compared to reference four-component data. Additional tests include SCF calculations of molecular properties such as absolute contact density and contact density shifts in copernicium fluoride compounds (CnFn, n = 2,4,6), as well as equation-of-motion coupled-cluster calculations of x-ray core-ionization energies of 5d- and 6d-containing molecules, where we observe an excellent agreement with reference data. To conclude, we are confident that our (e)amfX2C PCE correction models constitute a fundamental milestone toward a universal and reliable relativistic two-component quantum-chemical approach, maintaining the accuracy of the parent four-component one at a fraction of its computational cost.

Time-resolved CO2, CO, and N2 vibrational population measurements in Ns pulse discharge plasmas

Time-resolved CO2 and N2 vibrational populations and translational-rotational temperature are measured in a CO2–N2 plasma sustained by a ns pulse discharge burst in plane-to-plane geometry. Time-resolved, absolute number density of CO generated in the plasma is also inferred from the experimental data. CO2 and CO vibrational populations are measured by mid-IR, tunable quantum cascade laser absorption spectroscopy, and N2 vibrational populations are measured by the ns broadband vibrational CARS. Transient excitation of N2 and CO2 asymmetric stretch vibrational energy modes is detected during the discharge burst. The time-resolved rate of CO generation does not correlate with N2 or CO2(ν 3) vibrational temperatures, indicating that CO2 dissociation via the vibrational excitation is insignificant at the present conditions. The rate of CO generation decreases gradually during the discharge burst. The estimated specific energy cost of the CO product is close to that of N atoms in pure nitrogen, measured previously at similar operating conditions. Comparison of the experimental data with the kinetic modeling analysis indicates that CO2 dissociation in collisions with electronically excited N2 molecules is the dominant channel of CO generation at the present conditions, although the inferred CO yield in these processes is significantly lower than 1. The effect of vibrational energy transfer between N2 and CO2 on the plasma chemical processes is insignificant. The kinetic model underpredicts a rapid reduction of the N2 and CO2(ν 3) vibrational temperatures during the later half of the discharge burst and in the afterglow. V–T relaxation of N2 by N and O atoms generated in the ns pulse discharge plasma does not affect the vibrational relaxation rate in a significant way. However, rapid V–T relaxation of CO2 by O atoms has a significant effect on the relaxation rate. The difference between the experimental data and the modeling predictions may be due to the unknown scaling of the CO2–O V–T rates with the vibrational quantum number.

Importance of lower atmospheric forcing and magnetosphere-ionosphere coupling in simulating neutral density during the February 2016 geomagnetic storm

During geomagnetic storms a large amount of energy is transferred into the ionosphere-thermosphere (IT) system, leading to local and global changes in e.g., the dynamics, composition, and neutral density. The more steady energy from the lower atmosphere into the IT system is in general much smaller than the energy input from the magnetosphere, especially during geomagnetic storms, and therefore details of the lower atmosphere forcing are often neglected in storm time simulations. In this study we compare the neutral density observed by Swarm-C during the moderate geomagnetic storm of 31 January to 3 February 2016 with the Thermosphere-Ionosphere-Electrodynamics-GCM (TIEGCM) finding that the model can capture the observed large scale neutral density variations better in the southern than northern hemisphere. The importance of more realistic lower atmospheric (LB) variations as specified by the Whole Atmosphere Community Climate Model eXtended (WACCM-X) with specified dynamics (SD) is demonstrated by improving especially the northern hemisphere neutral density by up to 15% compared to using climatological LB forcing. Further analysis highlights the importance of the background atmospheric condition in facilitating hemispheric different neutral density changes in response to the LB perturbations. In comparison, employing observationally based field-aligned current (FAC) versus using an empirical model to describe magnetosphere-ionosphere (MI) coupling leads to an 7–20% improved northern hemisphere neutral density. The results highlight the importance of the lower atmospheric variations and high latitude forcing in simulating the absolute large scale neutral density especially the hemispheric differences. However, focusing on the storm time variation with respect to the quiescent time, the lower atmospheric influence is reduced to 1–1.5% improvement with respect to the total observed neutral density. The results provide some guidance on the importance of more realistic upper boundary forcing and lower atmospheric variations when modeling large scale, absolute and relative neutral density variations.

Study of EPR-based nanodielectrics under operational conditions for DC cable insulation

A model DC material based on ethylene propylene rubber (EPR) including the pure EPR and the EPR-based nanodielectrics incorporated with two different nanoclays, Kaoline and Talc, under operational conditions was investigated. The operational conditions include a 20 kV/mm electric field at 25 °C, a 20 kV/mm electric field at 50 °C with a thermal gradient, and a 40 kV/mm electric field at 50 °C with a thermal gradient and polarity reversal. Space charge distribution, surface potential, and electrical conductivity were measured to characterize the model DC material and interpret the discrete charge dynamics in the bulk and at the interface of the three samples. The experimental results revealed that the electrical conductivity of Talc-filled nanodielectric has the least dependency on electric field and temperature, which reduces the conductivity gradient across the dielectric. Moreover, the successful suppression of space charge and the lower dielectric time constant in the Talc-filled nanodielectric result in a tuning electric field in the bulk not only under normal operating conditions but also more importantly under polarity reversal conditions. The maximum of absolute charge density decreases from 10.6 C/m3 for EPR to 2.9 C/m3 for the Talc-filled nanodielectric under 40 kV/mm with polarity reversal and at 50 °C with the thermal gradient. The maximum of local electric field enhancement for the mentioned condition reduces significantly from 97 kV/mm, 142% enhancement, for EPR to 45 kV/mm, only 12.5% enhancement, for the Talc-filled nanodielectric.

Thrombus Density in Acute Basilar Artery Occlusion Depends on Slice Thickness and the Method of Manual Thrombus Delineation.

Introduction: High thrombus attenuation on CT has been suggested as a predictor of successful recanalization. It is as well speculated that thrombi of different density may be susceptible to different methods of mechanical thrombectomy. In this study we sought to determine the effect of different methods of manual thrombus delineation and reconstructed slice thickness on thrombus density. Material and Methods: Fifty-six patients with acute occlusion of the basilar artery treated with endovascular therapy were retrospectively included. Clinical, demographic, radiological and outcome parameters were collected. Two raters measured absolute and relative thrombus density employing three different methods (one region of interest, three regions of interest, whole thrombus delineation) and using three different reconstructed slice thicknesses (0.625, 2.5 and 5 mm) of the original admission CT. Results: Thirty-nine patients were successfully recanalized (thrombolysis in cerebral infarction score ≥ 2b). Good clinical outcome (modified Rankin scale ≤ 2) occurred significantly more often in the recanalized group (36 vs. 6%, p = 0.023, Fisher’s exact test), in the non-recanalized group symptomatic intracranial hemorrhage occurred more often (9 vs. 29%, p = 0.001, Fisher’s exact test). Absolute and relative thrombus density were largely different between methods and slice thicknesses. Multiple regression showed a decrease of thrombus density with increasing slice thickness (β = −3.98, p < 0.001) and logistic regression showed a statistically significant but very small relation between density and recanalization (β = 0.006, odds ratio (95% confidence interval) = 1.006 (1.003–1.01), p < 0.001). Conclusions: The methods for manual thrombus delineation and reconstructed slice thickness had a significant influence on absolute and relative thrombus density. Density alone may be of limited value as a predictive marker for recanalization success in acute occlusion of the basilar artery. Standards for density measurements must be defined when comparing different studies and when evaluating different methods of mechanical thrombectomy.

Quantitative microbiome analysis reveals the microbial community assembly along with its correlation with the flavor substances during the manufacturing process of Qingzhuan brick tea at an industrial scale

Several studies have shown that microorganisms are key factors in the transformation of dark tea chemicals. However, these studies have mainly used relative abundance to study the diversity of the microbial community during tea fermentation. The dynamics of microbial density and assembly of abundant and rare microbes remains poorly understood. In this study, the entire manufacturing process of Qingzhuan brick tea (QBT) was studied at an industrial scale. The succession of both bacterial and fungal communities was investigated using high-throughput sequencing along with quantitative PCR (qPCR) analysis. Changes in non-volatile flavor components, including soluble sugar (SS), total polyphenols (TP), nine tea catechins, caffeine, 21 free amino acids, and three tea pigments were detected. Mantel test showed that both bacterial and fungal community structures were significantly correlated with environmental variables during the microbial fermentation process but not during the aging process. The absolute microbial density was calculated based on qPCR gene copies and relative abundance. The quantitative microbiota network showed that dominant microbes constitute the basic skeleton of the network, while rare microbes have a stronger correlation with various flavor contents. These results help to understand the assembly of microbial communities and their role in the formation of tea flavor substances.

RBM45 is an m6A-binding protein that affects neuronal differentiation and the splicing of a subset of mRNAs.

SUMMARYN6-methyladenosine (m6A) is deposited co-transcriptionally on thousands of cellular mRNAs and plays important roles in mRNA processing and cellular function. m6A is particularly abundant within the brain and is critical for neurodevelopment. However, the mechanisms through which m6A contributes to brain development are incompletely understood. RBM45 acts as an m6A-binding protein that is highly expressed during neurodevelopment. We find that RBM45 binds to thousands of cellular RNAs, predominantly within intronic regions. Rbm45 depletion disrupts the constitutive splicing of a subset of target pre-mRNAs, leading to altered mRNA and protein levels through both m6A-dependent and m6A-independent mechanisms. Finally, we find that RBM45 is necessary for neuroblastoma cell differentiation and that its depletion impacts the expression of genes involved in several neurodevelopmental signaling pathways. Altogether, our findings show a role for RBM45 in controlling mRNA processing and neuronal differentiation, mediated in part by the recognition of methylated RNA.

CT Marker in Emergency Imaging of Acute Basilar Artery Occlusion: Thrombosis vs. Embolism.

Purpose: Acute basilar artery occlusion, a neurovascular emergency leading to high rates of morbidity and mortality, is usually diagnosed by CT imaging. The outcome is partly dependent on etiology, with a worse outcome in occlusions with underlying basilar artery stenosis. As this occlusion type requires a more complex angiographic therapy, this study aimed to develop new CT markers in emergency admission imaging to rapidly identify underlying stenosis. Methods: A total of 213 consecutive patients (female n = 91, age in years (mean/SD/range): 72/13/28–97), who received endovascular treatment at a single comprehensive stroke center for acute basilar artery occlusion, were included in this study. After applying strict inclusion criteria for imaging analyses, novel CT imaging markers, such as ‘absolute density loss’ (ADL) and relative thrombus attenuation (CTA-index), that measure perviousness, were assessed for n = 109 patients by use of CT-angiography and correlated to different occlusion patterns (thrombotic vs. embolic). Inter-observer agreement was assessed using an intraclass correlation coefficient for independent measures of a radiologist and a neuroradiologist. Associations between the imaging markers and clinical and interventional parameters were tested. Results: CT markers differ between the subgroups of basilar artery occlusions with and without underlying stenosis (for ADL: 169 vs. 227 HU (p = 0.03), for CTA-index: 0.55 vs. 0.70 (p < 0.001)), indicating a higher perviousness in the case of stenosis. A good inter-rater agreement was observed for ADL and CTA-index measures (ICC 0.92/0.88). For the case of embolic occlusions, a more pervious thrombus correlates to shorter time intervals, longer procedure times, and worse reperfusion success (p-values < 0.05, respectively). Conclusions: ADL and CTA-index are easy to assess in the emergency setting of acute basilar artery occlusion with the use of routinely acquired CT-angiography. They show a high potential to differentiate thrombotic from embolic occlusions, with an impact on therapeutic decisions and angiographic procedures. Measurements can be quickly performed with good reliability, facilitating implementation in clinical practice.

The association of age at menarche and adult height with mammographic density in the International Consortium of Mammographic Density

BackgroundEarly age at menarche and tall stature are associated with increased breast cancer risk. We examined whether these associations were also positively associated with mammographic density, a strong marker of breast cancer risk.MethodsParticipants were 10,681 breast-cancer-free women from 22 countries in the International Consortium of Mammographic Density, each with centrally assessed mammographic density and a common set of epidemiologic data. Study periods for the 27 studies ranged from 1987 to 2014. Multi-level linear regression models estimated changes in square-root per cent density (√PD) and dense area (√DA) associated with age at menarche and adult height in pooled analyses and population-specific meta-analyses. Models were adjusted for age at mammogram, body mass index, menopausal status, hormone therapy use, mammography view and type, mammographic density assessor, parity and height/age at menarche.ResultsIn pooled analyses, later age at menarche was associated with higher per cent density (β√PD = 0.023 SE = 0.008, P = 0.003) and larger dense area (β√DA = 0.032 SE = 0.010, P = 0.002). Taller women had larger dense area (β√DA = 0.069 SE = 0.028, P = 0.012) and higher per cent density (β√PD = 0.044, SE = 0.023, P = 0.054), although the observed effect on per cent density depended upon the adjustment used for body size. Similar overall effect estimates were observed in meta-analyses across population groups.ConclusionsIn one of the largest international studies to date, later age at menarche was positively associated with mammographic density. This is in contrast to its association with breast cancer risk, providing little evidence of mediation. Increased height was also positively associated with mammographic density, particularly dense area. These results suggest a complex relationship between growth and development, mammographic density and breast cancer risk. Future studies should evaluate the potential mediation of the breast cancer effects of taller stature through absolute breast density.

Crohn's disease active inflammation assessment with iodine density from dual-energy CT enterography: comparison with endoscopy and conventional interpretation.

To compare terminal ileum (TI) mucosal iodine density obtained at dual-energy CT enterography (DECTE) with conventional CT interpretation and endoscopy in patients with Crohn's disease (CD). Twenty-three CD patients (14 men; mean[SD] age:48.1[16.7] years) with endoscopy within 30days of DECTE were retrospectively identified. An inflammatory bowel disease gastroenterologist reviewed endoscopic images. Two radiologists qualitatively assessed the presence of active TI inflammation. Mean iodine density normalized to the aorta (I%), mean absolute iodine density (I), and iodine density standard deviation (ISD) from the distal 2cm ileum (TI) mucosa obtained using semiautomatic prototype software were compared with endoscopic assessment using Mann Whitney tests. The optimal threshold I% and I were determined from receiver operating curves (ROC). Sensitivity and specificity of conventional interpretation and determined iodine thresholds were compared using McNemar's test. Inter-reader agreement was assessed using kappa. A p < 0.05 indicated statistical significance. Twelve (52.1%) patients had endoscopic active inflammation. I% was 37.9[13.3]% for patients with and 21.7[7.5]% for patients without endoscopic active inflammation (p = 0.001). The optimal ROC threshold 24.6% had 100% sensitivity and 81.8% specificity (AUC = 0.909, 95% CI 0.777-1). I was 2.44[0.73]mg/mL for patients with and 1.77[1.00]mg/mL for patients without active endoscopic inflammation (p =0.0455). The optimal ROC threshold 1.78mg/mL I had 91.7% sensitivity and 63.6% specificity (AUC = 0.75, 95% CI 0.532-0.968). ISD was similar for patients with and without endoscopic active inflammation (0.82[0.33]mg/mL and 0.77[0.28]mg/mL, respectively, p = 0.37). Conventional interpretation sensitivity and specificity (R1/R2) were 83.3%/91.7% and 72.7%/54.5%, respectively (all p > 0.05) with moderate inter-reader agreement (Κ = 0.542[95% CI 0.0202-0.088]). Mean normalized iodine density is highly sensitive and specific for endoscopic active inflammation. DECTE could be considered as a surrogate to endoscopy in CD patients. Despite trends towards improved sensitivity and specificity compared with conventional interpretation, future larger studies are needed.

Deep learning for wheat ear segmentation and ear density measurement: From heading to maturity

Recent deep learning methods have allowed important steps forward in the automatic detection of wheat ears in the field. Nevertheless, it was still lacking a method able to both count and segment the ears, validated at all the development stages from heading to maturity. Moreover, the critical step of converting the ear count in an image to an ear density, i.e. a number of ears per square metre in the field, has been widely ignored by most of the previous studies. For this research, wheat RGB images have been acquired from heading to maturity in two field trials displaying contrasted fertilisation scenarios. An unsupervised learning approach on the YOLOv5 model, as well as the cutting-edge DeepMAC segmentation method were exploited to develop a wheat ear counting and segmentation pipeline that necessitated only a limited amount of labelling work for the training. An additional label set including all the development stages was built for validation. The average F1 score of ear bounding box detection was 0.93 and the average F1 score of segmentation was 0.86. To convert the ear counts to ear densities, a second RGB camera was used so that the distance between the cameras and the ears could be measured by stereovision. That distance was exploited to compute the image footprint at ear level, and thus divide the number of ears by this footprint to get the ear density. The obtained ear densities were coherent regarding the fertilisation scenarios but, for a same fertilisation, differences were observed between acquisition dates. This highlights that the measurement was not able to retrieve absolute ear densities for all the development stages and conditions. The deep learning measurement considered the most reliable outperformed observations from three human operators.

Changes in the vegetation density of Purwodadi Botanic Garden year 2015 - 2020 with Normalized Difference Vegetation Index (NDVI)

Purwodadi Botanical Gardens is one of the botanical gardens in Indonesia that used for conserve dry tropical plants and absorbs CO2 emissions. Therefore, it is important to know the changes that have occurred in the vegetation density in the Purwodadi Botanical Gardens in the last multi-temporal year (2015 – 2020). Qualitative descriptive research method is used in conducting this research. Field observations were carried out using the quadratic transect method in order to validate the data from Landsat-8 image processing and identifying the absolute density and relative density in the field. Secondary data is also used to determine changes in vegetation density using remote sensing techniques with radiometric correction processes to improve image quality due to surface reflection errors and NDVI (Normalized Difference Vegetation Index) which is used as the final analysis to obtain the results of vegetation density. The results of vegetation density increased from 2015 - 2020 due to the number of trees that grew and developed well, coupled with the regular planting of trees and other plants every year. This certainly has an impact on the air produced being cleaner and lower in temperature so that it can provide convenience for Purwodadi Botanical Garden tourists.

Cross-polarized common-path temporal interferometry for high-sensitivity strong-field ionization measurements.

Absolute density measurements of low-ionization-degree or low-density plasmas ionized by lasers are very important for understanding strong-field physics, atmospheric propagation of intense laser pulses, Lidar etc. A cross-polarized common-path temporal interferometer using balanced detection was developed for measuring plasma density with a sensitivity of ∼0.6 mrad, equivalent to a plasma density-length product of ∼2.6 × 1013 cm-2 if using an 800 nm probe laser. By using this interferometer, we have investigated strong-field ionization yield versus intensity for various noble gases (Ar, Kr, and Xe) using 800 nm, 55 fs laser pulses with both linear (LP) and circular (CP) polarization. The experimental results were compared to the theoretical models of Ammosov-Delone-Krainov (ADK) and Perelomov-Popov-Terent'ev (PPT). We find that the measured phase change induced by plasma formation can be explained by the ADK theory in the adiabatic tunneling ionization regime, while PPT model can be applied to all different regimes. We have also measured the photoionization and fractional photodissociation of molecular (MO) hydrogen. By comparing our experimental results with PPT and MO-PPT models, we have determined the likely ionization pathways when using three different pump laser wavelengths of 800 nm, 400 nm, and 267 nm.

Correlation between Population Density and COVID-19 Cases during the Third Wave in Malaysia: Effect of the Delta Variant

In this study, we describe the incidence and distribution of COVID-19 cases in Malaysia at district level and determine their correlation with absolute population and population density, before and during the period that the Delta variant was dominant in Malaysia. Methods: Data on the number of locally transmitted COVID-19 cases in each of the 145 districts in Malaysia, between 20 September 2020 and 19 September 2021, were manually extracted from official reports. The cumulative number of COVID-19 cases, population and population density of each district were described using choropleth maps. The correlation between population and population density with the cumulative number of COVID-19 cases in each district in the pre-Delta dominant period (20 September 2020–29 June 2021) and during the Delta dominant period (30 June 2021–19 September 2021) were determined using Pearson’s correlation. Results: COVID-19 cases were strongly correlated with both absolute population and population density (Pearson’s correlation coefficient (r) = 0.87 and r = 0.78, respectively). A majority of the districts had higher numbers of COVID-19 cases during the Delta dominant period compared to the pre-Delta period. The correlation coefficient in the pre-Delta dominant period was r = 0.79 vs. r = 0.86 during the Delta dominant period, whereas the pre-Delta dominant population density was r = 0.72, and in the Delta dominant period, r = 0.76. Conclusion: More populous and densely populated districts have a higher risk of transmission of COVID-19, especially with the Delta variant as the dominant circulating strain. Therefore, extra and more stringent control measures should be instituted in highly populated areas to control the spread of COVID-19.

The Status of Posidonia oceanica at Tremiti Islands Marine Protected Area (Adriatic Sea).

Simple SummaryThe seagrass Posidonia oceanica is the most important marine phanerogam of the Mediterranean Sea due to its meadows’ complexity, persistence, and extension. These habitats provide a suite of ecosystem goods and services, being of primary importance in marine conservation. Despite their central role in the coastal ecology, P. oceanica meadows are undergoing overall deterioration and fragmentation in the basin mostly due to anthropogenic impacts at local to global scales. In the last decades, several management measures have been proposed aiming to improve the meadow health conditions, while the periodic monitoring of P. oceanica meadows allows for verifying their effectiveness. Here, we report the results of the monitoring of P. oceanica at Tremiti Islands Marine Protected Area (Adriatic Sea, Italy) carried out in 2003, 2015, and 2020. A general worsening was observed, particularly enhanced by direct anthropogenic impacts mostly related to anchoring practices, as well as by a certain level of sedimentation possibly deriving from coastal development. However, the identification of these impacts and the correct management of human activities to mitigate them produced positive results in a relatively short time span.Posidonia oceanica meadows are Mediterranean coastal habitats of great conservation importance. This study is focused on a meadow located at Tremiti Islands Marine Protected Area (Adriatic Sea, Italy), which was monitored in 2003, 2015, and 2020 to evaluate its health state over time in relation to coastal human activities, which have been highly affecting this MPA for the last 20 years. To assess any change in the physiognomy of the meadow, rhizome density, percentage coverage, and lower limit progressions and/or regression over time were evaluated by scuba diving, while the distribution and extension of the meadow were assessed through habitat mapping using a side-scan sonar. Moreover, phenological and lepidochronological analyses were performed on the collected rhizomes to assess the leaf area index (LAI, m2m−2) and the rhizome age (lepidochronological years). Our study showed a general deterioration of P. oceanica meadow from 2003 to 2020, with a significant reduction of its absolute and relative rhizome density and LAI at almost all sampling stations, absence of renovation of the meadow, and lower limit regression and overall worsening of the main conservation status indicators. However, appropriate management actions, such as the establishment of mooring buoy fields, supported the improvement of the P. oceanica status at the local scale with a significant increase in density and LAI and the presence of active stolonization processes, suggesting that mitigation actions can play a crucial role in the conservation of this habitat. On the contrary, local anthropogenic impacts, especially anchoring and coastal development, markedly affect the resilience of P. oceanica meadows to global stressors, such as climate change.