Microbial Succession and Nitrogen Cycling in Cultured Biofilms as Affected by the Inorganic Nitrogen Availability

Biofilms play important roles in nutrients and energy cycling in aquatic ecosystems. We hypothesized that as eutrophication could change phytoplankton community and decrease phytoplankton diversity, ambient inorganic nitrogen level will affect the microbial community and diversity of biofilms and the roles of biofilms in nutrient cycling. Biofilms were cultured using a flow incubator either with replete inorganic nitrogen (N-rep) or without exogenous inorganic nitrogen supply (N-def). The results showed that the biomass and nitrogen and phosphorous accumulation of biofilms were limited by N deficiency; however, as expected, the N-def biofilms had significantly higher microbial diversity than that of N-rep biofilms. The microbial community of biofilms shifted in composition and abundance in response to ambient inorganic nitrogen level. For example, as compared between the N-def and the N-rep biofilms, the former consisted of more diazotrophs, while the latter consisted of more denitrifying bacteria. As a result of the shift of the functional microbial community, the N concentration of N-rep medium kept decreasing, while that of N-def medium showed an increasing trend in the late stage. This indicates that biofilms can serve as the source or the sink of nitrogen in aquatic ecosystems, and it depends on the inorganic nitrogen availability.</p

A Review on Properties, Opportunities, and Challenges of Transformer Oil-Based Nanofluids

The mineral oil or synthetic oil in conjunction with paper is mainly being applied as dielectric medium in many of the high voltage apparatus. However, the advent of high voltage levels such high voltage alternating current (HVAC) and high voltage direct current (HVDC) has prompted researchers to direct their focus onto an insulation system which can bear the rising high voltage levels. The modern insulating liquid material development is guided by various factors such as high electrical insulation requirements and other safety and economic considerations. Therefore transformer manufacturer companies have to design transformers with these new specific requirements. The transformer oil-based nanofluids with improved dielectric and thermal properties have the potential to replace mineral oil base products in the market place. They are favorable because they function more superior than mineral oil and they contribute definite insulating and thermal gains. This paper reviews recent status of nanofluids use as transformer oils. The nanofluids used as transformer oils are presented and their advantages are described in comparison with mineral oil. The multiple experimental works carried out by different researchers are described, providing an overview of the current research conducted on nanofluids. In addition scope and challenges being confronted in this area of research are clearly presented

Possible interpretation of the ZbZ_b(10610) and ZbZ_b(10650) in a chiral quark model

Motivated by the two charged bottomonium-like resonances $Z_b$(10610) and $Z_b$(10650) newly observed by the Belle collaboration, the possible molecular states composed of a pair of heavy mesons, $B\bar{B}, B\bar{B}^*, B^*\bar{B}^*, B_s\bar{B}$, etc (in S-wave), are investigated in the framework of chiral quark models by the Gaussian expansion method. The bound states $B\bar{B}^*$ and $B^*\bar{B}^*$ with quantum numbers $I(J^{PC})=1(1^{+-})$, which are good candidates for the $Z_b(10610)$ and $Z_b(10650)$ respectively, are obtained. Other three bound states $B\bar{B}^*$ with $I(J^{PC})=0(1^{++})$, $B^*\bar{B}^*$ with $I(J^{PC})=1(0^{++}), 0(2^{++})$ are predicted. These states may be observed in open-bottom or hidden-bottom decay channel of highly excited $\Upsilon$. When extending directly the quark model to the hidden color channel of the multi-quark system, more deeply bound states are found. Future experimental search of those states will cast doubt on the validity of applying the chiral constituent quark model to the hidden color channel directly.Comment: 13 pages, 1 figure, title and some arguments in the abstract and section 5 are revised, results unchange

Apple weight estimation based on joint image optimal feature extraction and improved RBF neural network

Objective: Taking Aksu apples as an example, a joint image optimal feature extraction and improved RBF neural network learning apple weight estimation method is designed to overcome the high cost and large error of manual grading and weighing. Methods: Firstly, an apple image acquisition system was established to obtain apple foreground image information. Secondly, the optimal subset extraction strategy for apple image feature sets was designed, by transforming the process of extracting the optimal subset into an objective function optimization problem, and an improved discrete locust optimization algorithm was designed to obtain the optimal apple image feature subset. Finally, a weight estimation model for apples based on RBF neural network learning was constructed, with the optimal feature subset as network input. The locust optimization algorithm was used to optimize the configuration of RBF neural network hyperparameters, to achieve effective estimation of apple weight. Results: The proposed apple weight estimation method had higher accuracy, with an average relative error rate of 1.23% for weight estimation. Conclusion: This method can effectively achieve apple weight estimation and can also be applied to other fruits with similar axisymmetric shapes for weight estimation

Widespread upper-ocean deoxygenation in the Alpine-Mediterranean Tethys during the Toarcian Oceanic Anoxic Event

The early Toarcian (∼183 Ma) was characterized by pronounced climate warming associated with massive release of 13C-depleted carbon to the exogenic system, as evidenced by globally recognized negative carbon-isotope excursions (N-CIE) in biospheric carbon reservoirs. Global warming during this interval triggered a variety of environmental perturbations, of which large-scale marine deoxygenation (as indicated by the presence of widespread organic carbon-rich deposits) is arguably diagnostic and led to the naming of the interval in question as the Toarcian Oceanic Anoxic Event (T-OAE). Nevertheless, the spatial variability of water-column redox during the T-OAE is unclear because most sedimentological and geochemical methods used to infer marine redox are likely reflective of bottom-water and/or pore-water conditions. Here we report new I/(Ca + Mg) and Cerium (Ce)-anomaly data from two carbonate successions from northern Italy that encompass the T-OAE interval. Both successions were deposited in the Alpine-Mediterranean Tethys; one in a shallow-water platform setting and the other within a pelagic environment. Both successions record an abrupt drop in I/(Ca + Mg) values, coupled with positive excursions in Ce-anomaly records at the onset of the T-OAE N-CIE. The synchronized changes in marine iodate depletion and Ce enrichment suggest widespread and significant upper-ocean deoxygenation in the Alpine-Mediterranean Tethys. This redox pattern is attributed to an expanded oxygen minimum zone (OMZ) formed as a result of sluggish oceanic circulation under climate warming, augmented by enhanced dissolved oxygen consumption due to increased nutrient availability and the consequent eutrophication in both proximal and distal settings. Because reduced seawater dissolved oxygen [O2] would increase the ecological stress and constrict any potentially hospitable habitats, the broad synchroneity between biotic turnovers and upper-ocean deoxygenation in the Alpine-Mediterranean Tethys is compatible with a potential causal link

Heavy metal characteristics of vegetables and their soils in Foshan City

Investigation of the vegetable garden soil in Foshan City 4 kinds of heavy metals Cu, Pb, Zn and Cd in the total and different forms of content, while also investigating a variety of vegetables and edible part of the Cd content. The results show that, Foshan City, the heavy metal content in vegetable field exceed the national and the background value of Guangdong Province, the pollution index to the maximum Cd, Cu, followed by, Cd elements of the highest validity coefficients. Foshan City, edible part of vegetables found excessive Cd, leafy soil Cd content and Cd the full amount of exchangeable manganese content and the amount of state showed a significant positive correlation. The state of heavy metal content of vegetable soil in Foshan city was investigated. The total content and available content of 4 heavy metal elements (Cd, Pb, Zn, and Cu) were analyzed and measured. The result indicated that the heavy metal content of vegetable soil in Foshan city was greater than the average in other areas throughout Guangdong Province or even the whole country. The valid coefficient of Cd element was the greatest. The content of Cd in vegetables was greater than the state vegetable sanitation standard. In different kinds of vegetables, the content of Cd in leaf-vegetable had very significant correlation with the content of different sort Cd in soil. which indicated that the content of Cd in vegetables was affected by the content of Cd in soil

Make Continual Learning Stronger via C-Flat

Model generalization ability upon incrementally acquiring dynamically updating knowledge from sequentially arriving tasks is crucial to tackle the sensitivity-stability dilemma in Continual Learning (CL). Weight loss landscape sharpness minimization seeking for flat minima lying in neighborhoods with uniform low loss or smooth gradient is proven to be a strong training regime improving model generalization compared with loss minimization based optimizer like SGD. Yet only a few works have discussed this training regime for CL, proving that dedicated designed zeroth-order sharpness optimizer can improve CL performance. In this work, we propose a Continual Flatness (C-Flat) method featuring a flatter loss landscape tailored for CL. C-Flat could be easily called with only one line of code and is plug-and-play to any CL methods. A general framework of C-Flat applied to all CL categories and a thorough comparison with loss minima optimizer and flat minima based CL approaches is presented in this paper, showing that our method can boost CL performance in almost all cases. Code will be publicly available upon publication

Enhanced Catalytic Performance of Pd/HMIL-121 Catalysts with Hierarchical Porosity for Selective Hydrogenation of Phenylacetylene: Mechanistic Insights and Comparative Analysis

Metal–organic frameworks (MOFs) with Al metal nodes, being stable and cost-effective materials, are well-suited for use as catalyst supports. In this study, a hierarchical Pd/HMIL-121 catalyst with adjustable pore sizes was synthesized through heat treatment using MIL-121 as the support. The study reveals that as thermal treatment intensity escalates, the pore volume and specific surface area of HMIL-121 initially rise and then decrease. Concurrently, as the pore volume and BET specific surface area increase, the styrene selectivity improves, and the rate of phenylacetylene conversion accelerates. This is attributed to the larger pore volume significantly enhancing the internal diffusion of phenylacetylene and styrene.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author