Modeling the dielectric properties of wood

A method for calculating the complex dielectric permittivity of an anisotropic wood structure at microwave frequencies is presented. A numerical model for describing the 3D wood structure containing fibers, rays, vessels and cracks with changeable dimensions and material composition is built. This model is introduced into an efficient solver that calculates the effective dielectric constant of any 3D structure of dielectric materials. Using our numerical model we succeeded in theoretically reproducing the results of recent measurements of the dielectric permittivity of wood, in various directions and various moisture contents. The qualitative agreement is realistic, reproducing all the trends of the changes in ɛ as the direction of the electric field and the moisture content are varied. The quantitative agreement is practical and reliable for engineering calculations with an average deviation of ±10% in ɛ′ and ±5% in ɛ′′. As microwave processing of wood involves internal temperatures as high as 150°C and pressures of up to 5 atm, the dielectric properties of wood were also calculated with the same numerical model by simulating high internal temperature and pressure. A comparison between the calculated and measured values shows once again how accurate the model reproduces the empirical study.     

Influence of different long-term mineral–organic fertilization on yield,nutrient balance and soil C and N contents of a sandy loess (Haplic Phaeozem) in middle Germany

In a long-term field trial (Halle, Germany, founded in 1949 by K. Schmalfuß, soil type Haplic Phaeozem), the effects of different mineral and organic fertilization on dry matter yields, soil C and N contents and N balances were investigated. Over a period of 60 years, yields increased on average in all cultivated crops (winter and spring cereals, potatoes, sugar beets, silage maize), even without any fertilization. Nitrogen deficiency in unfertilized and PK treatments caused strong decreases in yield (up to 48%) in comparison with the N2PK standard treatment. The effect of omitting K or P supply was smaller (up to 18% and 7% yield reduction, respectively). The highest yields were obtained with high mineral N + PK application and (except winter wheat) with farmyard manure in combination with mineral fertilization. The N balances were negative in all treatments. However, if N immission from the air (40 kg ha^?1 a^?1) was included in the calculation, N balances were negative only in low N treatments. The soil C and N contents increased up to 1975. A considerable decrease has been seen since about 1985. The highest soil C and N contents were observed in the farmyard manure treatments. In addition to fertilization effects, this development of soil properties reflects changes in environmental pollution, climatic changes, as well as shifts in cultivation methods like tillage depths, over recent decades.     

Transient or persistent norovirus infection does not alter the pathology of Salmonella typhimurium induced intestinal inflammation and fibrosis in mice

Murine noroviruses (MNV) are currently the most prevalent viruses infecting mouse research colonies. Concurrent infection of research mice with these viruses can dramatically alter the experimental outcome in some research models, but not others. In this report, we investigated the effect of MNV1 and MNV4 on a murine model of intestinal inflammation and fibrosis induced by Salmonella typhimurium infection in C57BL/6 mice. Subsequent co-infection of these mice with MNV1 or MNV4 did not lead to major changes in histopathology, the inflammatory response, or the fibrotic response. Thus, MNV does not substantially alter all gastrointestinal research models, highlighting the importance of investigating potential alterations in the research outcome by MNV on an individual basis. We hypothesize that this is particularly important in cases of research models that use immunocompromised mice, which could be more sensitive to MNV infection-induced changes.     

Sources and rates of nitrous oxide emissions from grazed grassland after application of N-labelled mineral fertilizer and slurry

Nitrogen (N) fertilizer application and grazing are known to induce nitrous oxide (N₂O) emissions from grassland soils. In a field study, general information on rates of N₂O emission, the effect of cattle grazing and the type (mineral fertilizer, cattle slurry) and amount of N supply on the flux of N₂O from a sandy soil were investigated. N₂O emissions from permanent grassland managed as a mixed system (two cuts followed by two grazing cycles) were monitored over 11 months during 2001-2002 in northern Germany using the closed chamber method. The field experiment consisted of four regionally relevant fertilizer combinations, i.e. two mineral N application rates (0 and 100 kg N ha⁻¹ yr⁻¹) and two slurry levels (0 and 74 kg N ha⁻¹ yr⁻¹).Mean cumulative N₂O-N loss was 3.0 kg ha⁻¹ yr⁻¹, and the cumulative ¹⁵N-labelled N₂O emissions varied from 0.03% to 0.19% of the ¹⁵N applied. ¹⁵N labelling indicated that more N₂O was emitted from mineral N than from slurry treated plots, and in all treatments the soil N pool was always clearly the major source of N₂O. Regarding the total cumulative N₂O losses, differences among treatments were not significant, which was caused by: (i) a high variance in emissions during and after cattle grazing due to the random distribution of excrements and by (ii) high N₂ fixation of white clover in the 0 kg N ha⁻¹ treatments, which resulted in similar N status of all treatments. However before grazing started, treatments showed significant differences. After cattle grazing in summer, N₂O emission rates were higher than around the time of spring fertilizer application, or in winter. Grazing resulted in N₂O flux rates up to 489 μg N₂O-N m⁻² h⁻¹ and the grazing period contributed 31-57% to the cumulative N₂O emission. During freeze-thaw cycles in winter (December-February) N₂O emission rates of up to 147 μg N₂O-N m⁻² h⁻¹ were measured, which contributed up to 26% to the annual N₂O flux. The results suggest that N fertilizer application and grazing caused only short-term increases of N₂O flux rates whereas the major share of annual N₂O emission emitted from the soil N pool. The significantly increased N₂O fluxes during freeze-thaw cycles show the importance of emission events in winter which need to be covered by measurements for obtaining reliable estimates of annual N₂O emissions.     

Evolutionarily assembled cis-regulatory module at a human ciliopathy locus

Neighboring genes are often coordinately expressed within cis-regulatory modules, but evidence that nonparalogous genes share functions in mammals is lacking. Here, we report that mutation of either TMEM138 or TMEM216 causes a phenotypically indistinguishable human ciliopathy, Joubert syndrome. Despite a lack of sequence homology, the genes are aligned in a head-to-tail configuration and joined by chromosomal rearrangement at the amphibian-to-reptile evolutionary transition. Expression of the two genes is mediated by a conserved regulatory element in the noncoding intergenic region. Coordinated expression is important for their interdependent cellular role in vesicular transport to primary cilia. Hence, during vertebrate evolution of genes involved in ciliogenesis, nonparalogous genes were arranged to a functional gene cluster with shared regulatory elements.     

Natural iron isotope variations in human blood

Isotopic analysis of human blood and liver and muscle tissue indicates that each individual bears a long-term iron (Fe) isotope signature in the blood. Blood and tissue differ slightly in isotopic composition and are depleted by up to 2.6 per mil in 56Fe relative to 54Fe when compared to dietary Fe. The 56Fe/54Fe isotope ratio in the blood of males is, on average, lower by 0.3 per mil than that of females. These results suggest that Fe isotope effects in the blood reflect differences in intestinal Fe absorption between individuals and genotypes.     

Effect of slurry application techniques on nitrous oxide emission from temperate grassland under varying soil and climatic conditions

The effect of slurry application techniques and slurry N stabilizing strategies on nitrous oxide emission from grasslands is poorly understood and, therefore, can result in large uncertainties in national/regional inventories. Field experiments were, thus, conducted to estimate the effect of different fertilization techniques on nitrous oxide (N₂O) emissions. Fertilizer was applied (135–270 kg N ha⁻¹ year⁻¹) as calcium ammonium nitrate (CAN), untreated or treated cattle slurry. The slurry was either treated with sulfuric acid (target pH = 6.0), applied using trailing shoes or treated with 3,4-dimethyl pyrazole phosphate and applied via slot injection. N₂O fluxes were sampled using the closed chamber technique. Cumulative N₂O emissions ranged 0.1–2.9 kg N ha⁻¹ year⁻¹ across the treatment, sites and years. The N application techniques showed inconsistent effects on soil mineral N content, cumulative N₂O emission and N yield. The fertilizer replacement value of slurry was low due to low N use efficiencies at the sites. However, a close positive relationship (r = 0.5; p = .013) between slurry value and biomass yield was observed, highlighting the benefit of high slurry value on crop productivity. N₂O-N emission factors were low for all treatments, including CAN, but were 2–6 times higher in 2019 than in 2020 due to lower precipitation in 2020. Variations in N₂O emission were largely explained by soil and climatic factors. Even with the low N₂O emissions, this study highlights the benefit (significant mitigation of N₂O emissions) of replacing the increasingly expensive chemical fertilizer N with input from slurry under favourable conditions for denitrification.     

Genotypic and environmental variation in water soluble carbohydrate content of silage maize

The concentration of water soluble carbohydrates (WSC) is a main determinant of the ensiling potential of forages and the aerobic stability of silages. The aims of the present study were to assess the impact of genotype on the seasonal changes of WSC concentration, to adapt and calibrate the FONSCH (FOrage NonStructural CarboHydrates) model – originally developed for forage grasses – for silage maize, and finally to conduct a long-term simulation study for quantifying weather-related variability of WSC content. A 3-year field experiment (2001–2003) was conducted in northern Germany to evaluate differences in WSC content among commercial silage maize varieties and to provide calibration data for modelling. Eight varieties covering three maturity groups (early, mid-early and mid-late) were investigated. On six dates throughout the vegetation period the plants were harvested, separated into ear and stover, and freeze–dried for subsequent determination of WSC. Ear, stover, and whole crop WSC content was influenced by genotype and environmental conditions. Genotypic effects were most pronounced in the early grain filling period. At silage maturity, an effect of variety on whole crop WSC content was found in the mid-early group only, accounting for a difference of 44.8 g WSC kg⁻¹ DM. FONSCH model calibration showed good agreement between observed and calculated WSC contents, with RMSE below 27.6 g WSC kg⁻¹ DM and r² above 0.84. Parameter estimates revealed a substantial influence of temperature and solar radiation on WSC content, while plant available soil water had minimal impact. Successful model validation with an independent data set allowed us to perform a 30-year simulation study, where variation among varieties and years of up to 68.8 and 186.5 g WSC kg⁻¹ DM, respectively, demonstrated a larger impact of environmental conditions compared to genotype.     

Short-term effects of single or combined application of mineral N fertilizer and cattle slurry on the fluxes of radiatively active trace gases from grassland soil

After implementation of legislative measures for the reduction of environmental hazards from nitrate leaching and ammonia volatilisation when using organic manures and fertilizers in Europe, much attention is now paid to the specific effects of these fertilizers on the dynamics of global warming-relevant trace gases in soil. Particularly nitrogen fertilizers and slurry from animal husbandry are known to play a key role for the CH₄ and N₂O fluxes from soils. Here we report on a short-term evaluation of trace gas fluxes in grassland as affected by single or combined application of mineral fertilizer and organic manure in early spring. Methane fluxes were characterised by a short methane emission event immediately after application of cattle slurry. Within the same day methane fluxes returned to negative, and on average over the 4-day period after slurry application, only a small but insignificant trend to reduced methane oxidation was found. Nitrous oxide emissions showed a pronounced effect of combined slurry and mineral fertilizer application. In particular fresh cattle slurry combined with calcium ammonium nitrate (CAN) mineral fertilizer induced an increase in mean N₂O flux during the first 4 days after application from 10 to 300 μg N₂O-N m⁻² h⁻¹. ¹⁵N analysis of emitted N₂O from ¹⁵N-labelled fertilizer or manure indicated that easily decomposable slurry C compounds induced a pronounced promotion of N₂O-N emission derived from mineral CAN fertilizer. Fluxes after application of either mineral fertilizer or slurry alone showed an increase of less than 5-fold. The NO_x sink strength of the soil was in the range of −6 to −10 μg NO_x-N m⁻² h⁻¹ and after fertilization it showed a tendency to be reduced by no more than 2 μg NO_x-N m⁻² h⁻¹, which was a result of both, increased NO emission and slightly increased NO₂ deposition. Associated determination of the N₂O:N₂ emission ratio revealed that after mineral N application (CAN) a large proportion (c. 50%) was emitted as N₂O, while after application of slurry with easily decomposable C and predominantly -N serving as N-source, the N₂O:N₂ emission ratio was 1:14, i.e. was changed in favour of N₂. Our work provides evidence that particularly the combination of slurry and nitrate-containing N fertilizers gives rise to considerable N₂O emissions from mineral fertilizer N pool.