Non-Coexistence of Infinite Clusters in Two-Dimensional Dependent Site Percolation

This paper presents three results on dependent site percolation on the square lattice. First, there exists no positively associated probability measure on {0,1}^{Z^2} with the following properties: a) a single infinite 0cluster exists almost surely, b) at most one infinite 1*cluster exists almost surely, c) some probabilities regarding 1*clusters are bounded away from zero. Second, we show that coexistence of an infinite 1*cluster and an infinite 0cluster is almost surely impossible when the underlying probability measure is ergodic with respect to translations, positively associated, and satisfies the finite energy condition. The third result analyses the typical structure of infinite clusters of both types in the absence of positive association. Namely, under a slightly sharpened finite energy condition, the existence of infinitely many disjoint infinite self-avoiding 1*paths follows from the existence of an infinite 1*cluster. The same holds with respect to 0paths and 0clusters.Comment: 17 pages, 1 figur

A Computational Tool for Pre-operative Breast Augmentation Planning in Aesthetic Plastic Surgery

Abstract—Breast augmentation was the most commonly performed cosmetic surgery procedure in 2011 in the United States. Although aesthetically pleasing surgical results can only be achieved if the correct breast implant is selected from a large variety of different prosthesis sizes and shapes available on the market, surgeons still rely on visual assessment and other subjective approaches for operative planning because of lacking objective evaluation tools. In this paper we present the development of a software prototype for augmentation mammaplasty simulation solely based on 3D surface scans, from which patient-specific finite element models are generated in a semi-automatic process. The finite element model is used to pre-operatively simulate the expected breast shapes using physical soft tissue mechanics. Our approach uses a novel mechanism based on so-called displacement templates, which, for a specific implant shape and position, describe the respective internal body forces. Due to a highly efficient numerical solver we can provide immediate visual feedback of the simulation results, and thus the software prototype can be integrated smoothly into the medical workflow. The clinical value of the developed 3D computational tool for aesthetic breast augmentation surgery planning is demonstrated in patientspecific use cases

Development of a photon Monte Carlo radiative heat transfer solver for CFD applications

Radiative heating can play an important role during atmospheric re-entry, combustion processes, and high-enthalpy shock tunnel experiments. The present work details the development of a scalable photon Monte Carlo radiative heat transfer solver based on the open-source SPARTA DSMC code; its verification, coupling with the DLR FlowSimulator framework, and subsequent application

X-ray structure of the Rhodobacter sphaeroides reaction center with an M197 Phe→\toHis substitution clarifies the properties of the mutant complex

The first steps of the global process of photosynthesis take place in specialized membrane pigment–protein complexes called photosynthetic reaction centers (RCs). The RC of the photosynthetic purple bacterium Rhodobacter sphaeroides, a relatively simple analog of the more complexly organized photosystem II in plants, algae and cyanobacteria, serves as a convenient model for studying pigment–protein interactions that affect photochemical processes. In bacterial RCs the bacteriochlorophyll (BChl) dimer P serves as the primary electron donor, and its redox potential is a critical factor in the efficient functioning of the RC. It has previously been shown that the replacement of Phe M197 by His strongly affects the oxidation potential of P (E$_m$ P/P$^+$), increasing its value by 125 mV, as well as increasing the thermal stability of RC and its stability in response to external pressure. The crystal structures of F(M197)H RC at high resolution obtained using various techniques presented in this report clarify the optical and electrochemical properties of the primary electron donor and the increased resistance of the mutant complex to denaturation. The electron-density maps are consistent with the donation of a hydrogen bond from the imidazole group of His M197 to the C2-acetyl carbonyl group of BChl P$_B$. The formation of this hydrogen bond leads to a considerable out-of-plane rotation of the acetyl carbonyl group and results in a 1.2 Å shift of the O atom of this group relative to the wild-type structure. Besides, the distance between BChl P$_A$ and P$_B$ in the area of pyrrole ring I was found to be increased by up to 0.17 Å. These structural changes are discussed in association with the spectral properties of BChl dimer P. The electron-density maps strongly suggest that the imidazole group of His M197 accepts another hydrogen bond from the nearest water molecule, which in turn appears to form two more hydrogen bonds to Asn M195 and Asp L155. As a result of the F(M197)H mutation, BChl P$_B$ finds itself connected to the extensive hydrogen-bonding network that pre-existed in wild-type RC. Dissimilarities in the two hydrogen-bonding networks near the M197 and L168 sites may account for the different changes of the E$_m$ P/P$^+$ in F(M197)H and H(L168)F RCs. The involvement of His M197 in the hydrogen-bonding network also appears to be related to stabilization of the F(M197)H RC structure. Analysis of the experimental data presented here and of the data available in the literature points to the fact that the hydrogen-bonding networks in the vicinity of BChl dimer P may play an important role in fine-tuning the redox properties of the primary electron donor

Erosion rates along Sobo-Sise Cliff 1965-2018

Permafrost thaw and ice wedge degradation lead to drastic landscape changes in the permafrost region. With this data set we investigated the cliff retreat of the Sobo-Sise Cliff (SSC), a high ice-bearing yedoma cliff in the Lena River Delta. The 1,660 m long cliff SSC extends from 72°32'34 N / 128°15'59 E to 72°32'06 N / 128°18'21 E and is located on the Sardakhskaya channel, which is one of the main Lena river branches in the Lena River Delta. Erosion rates for the SSC were determined based on satellite images from different sensors (Corona, Hexagon, Landsat, Planet cube-sat) for the period 1965-2018. Cliff front lines were manually digitized and erosion rates were calculated with the Digital Shoreline Analysis System (DSAS) tool (Himmelstoos et al. 2018). The study Fuchs et al. (2020) (DOI:10.3389/feart.2020.00336) shows that the up to 27.7 m high SSC erodes in average 15.7 m yr-1 (2015-2018). During the entire observed time period from 1965-2018, the SSC retreated in average 484 m (ranging from 322 - 680 m). This dataset includes the mean annual erosion rates of the yedoma SSC for the time periods 1965-1975, 1975-2000, 2000-2005, 2005-2010, 2010-2015, and 2015-2018, as well as the absolute cliff retreat rates over the entire period 1965-2018, which are derived from remote sensing imagery analyzed with the DSAS tool (doi:10.1594/PANGAEA.918505). Related trend data for this region, based on Landsat trend analysis are available at doi:10.1594/PANGAEA.884136 (Nitze, 2018)

Erosion rates of the Sobo-Sise yedoma permafrost cliff in the Lena River Delta derived from remote sensing imagery

Permafrost thaw and ice wedge degradation lead to drastic landscape changes in the permafrost region. With this data set we investigated the cliff retreat of the Sobo-Sise Cliff (SSC), a high ice-bearing yedoma cliff in the Lena River Delta. The 1,660 m long cliff SSC extends from 72°32'34 N / 128°15'59 E to 72°32'06 N / 128°18'21 E and is located on the Sardakhskaya channel, which is one of the main Lena river branches in the Lena River Delta. Erosion rates for the SSC were determined based on satellite images from different sensors (Corona, Hexagon, Landsat, Planet cube-sat) for the period 1965-2018. Cliff front lines were manually digitized and erosion rates were calculated with the Digital Shoreline Analysis System (DSAS) tool (Himmelstoos et al. 2018). The study Fuchs et al. (2020) (doi:10.3389/feart.2020.00336) shows that the up to 27.7 m high SSC erodes in average 15.7 m yr-1 (2015-2018). During the entire observed time period from 1965-2018, the SSC retreated in average 484 m (ranging from 322 - 680 m). This data set compilation consist of three GIS shapefiles with a corresponding metadata file and a table of the mean annual erosion rates of the yedoma SSC for the time periods 1965-1975, 1975-2000, 2000-2005, 2005-2010, 2010-2015, and 2015-2018, as well as the absolute cliff retreat rates over the entire period 1965-2018, which are derived from remote sensing imagery analyzed with the DSAS tool. In addition, the cliff front lines for each investigated time step are provided as well as the separation between yedoma and alas deposits for each time step. Related trend data for this region, based on Landsat trend analysis are available at: doi:10.1594/PANGAEA.884136 (Nitze, 2018)

Migration of aluminum from food contact materials to food—a health risk for consumers? Part II of III: migration of aluminum from drinking bottles and moka pots made of aluminum to beverages

Abstract Background Drinking bottles and stove-top moka pots made of aluminum have become very popular. Storing drinks in bottles and preparing coffee in a moka pot may result in the migration of aluminum to the beverage. Results/Conclusions In a systematic study of aluminum drinking bottles, it has been shown that drinking a mixture of apple juice and mineral water in an aluminum bottle may reach 86.6% of the total weekly intake (TWI) for adults, and drinking tea from an aluminum bottle may exceed the TWI (145%) for a child weighing 15 kg. In contrast, preparing coffee in an aluminum moka pot results in a maximum of 4% to TWI, if an average of 3.17 L coffee is consumed per week, even if the pots are washed in the dishwasher, against the explicit instructions of the manufacturer

Migration of aluminum from food contact materials to food—a health risk for consumers? Part III of III: migration of aluminum to food from camping dishes and utensils made of aluminum

Abstract Background When cooking on a barbecue grill, consumers often use aluminum grill pans. For one, the pan catches the fats and oils that would drip into the embers causing the formation of potentially noxious smoke, and the pan also protects the food from being burned by direct heat from the coals. In addition, new aluminum products for use in ovens and grills are becoming increasingly popular. Due to their light weight and excellent heat transfer camping, utensils made of aluminum are, for example, often used by fishermen and mountain climbers. Preparing food in aluminum utensils can, however, result in migration of the aluminum to the foodstuffs. Results/Conclusions In this study presented here, it was found that the transfer limit of 5.00 mg/L for aluminum is not exceeded using simulants for oil or for tap water; however, with an aqueous solution of 0.5% citric acid, the limit is clearly exceeded at 638 mg/L. This means that the Tolerable Weekly Intake (TWI) is exceeded by 298% for a child weighing 15 kg and for an adult weighing 70 kg it is equivalent to 63.8% of the TWI, assuming a daily uptake of 10 mL marinade containing lemon juice over a period of 1 week. Preparation of a fish dish with a marinade containing lemon juice in camping dishes would result in the TWI being exceeded by 871% for a child weighing 15 kg and by 187% for an adult weighing 70 kg assuming a daily uptake of 250 g over a period of 1 week

Migration of aluminum from food contact materials to food—a health risk for consumers? Part I of III: exposure to aluminum, release of aluminum, tolerable weekly intake (TWI), toxicological effects of aluminum, study design, and methods

Abstract Background In spite of the prevalence of aluminum in nature, no organism has been found to date which requires this element for its biological functions. The possible health risks to human beings resulting from uptake of aluminum include detrimental effects to the hemopoietic system, the nervous system and bones. Aluminum is used in many fields and occurs in numerous foodstuffs. Food contact materials containing aluminum represent an anthropogenic source of dietary aluminum. Results As a result of their frequent use in private households a study was undertaken to detect migration of this metal to foodstuffs from drink containers, coffee pots, grill pans, and camping cookware made of aluminum. Conclusions An estimate of the health risk to consumers is calculated, based on the tolerable weekly intake (TWI) specified by the European Food Safety Authority of 1 mg/kg body weight for all groups of people. In some instances the TWI is significantly exceeded, dependent upon the food contact material and the food itself

Accumulation Potentials of Perfluoroalkyl Carboxylic Acids (PFCAs) and Perfluoroalkyl Sulfonic Acids (PFSAs) in Maize (<i>Zea mays</i>)

Uptake of perfluoroalkyl acids (PFAAs) by maize represents a potential source of exposure for humans, either directly or indirectly via feed for animals raised for human consumption. The aim of the following study was, therefore, to determine the accumulation potential of perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) in maize (<i>Zea mays</i>). Two different concentrations of PFAAs were applied as aqueous solution to the soil to attain target concentrations of 0.25 mg or 1.00 mg of PFAA per kg of soil. Maize was grown in pots, and after harvesting, PFAA concentrations were measured in the straw and kernels of maize. PFCA and PFSA concentrations of straw decreased significantly with increasing chain length. In maize kernels, only PFCAs with a chain length ≤ C8 as well as perfluorobutanesulfonic acid (PFBS) were detected. The highest soil-to-plant transfer for both straw and kernels was determined for short-chained PFCAs and PFSAs