An Experimental and Modelling Study of Cu2+ Binding on Humic Acids at Various Solution Conditions. Application of the NICA-Donnan Model

Humic substances are characterized by a strong binding capacity for both metals and organic pollutants, affecting their mobility and bioavailability. The understanding of the mechanisms of proton and metal binding to humic substances is of fundamental importance in geochemical modelling and prediction of cation speciation in the environment. This work reports results on copper binding on humic acids obtained through a thorough experimental and modelling approach. Two humic acids, a reference purified peat humic acid isolated by the International Humic Substances Society (IHSS) and a humic acid from a Greek soil, were experimentally studied at various pH values (4, 6 and 8), humic acid concentrations (ranging from 20 to 200 mg?L^?1) and ionic strength (0.1 and 0.01 M NaNO₃). The binding of copper to humic acids was determined over wide ranges of copper ion concentrations using a copper ion selective electrode. The copper binding isotherms obtained at different conditions have shown that copper binding is dependent on the pH and ionic strength of the solution and on the concentration of both humic acids. Copper binding experimental data were fitted to non-ideal competitive adsorption NICA-Donnan model and the model parameter values were calculated. Both Cu²⁺ and CuOH⁺ species binding to humic acid with different binding affinities were considered. Two sets of the NICA-Donnan parameters have been calculated: one for humic acid concentrations of ??100 mg?L^?1and one for humic acid concentration of 20 mg?L^?1. The meaning of the parameters values for each concentration level is also discussed.     

Comparison of absorbable and nonabsorbable sutures for intradermal skin closure in cats

Paired skin incisions were made in 6 cats and closed intradermally with the copolymer of glycolide, ɛ-caprolacton, and trimethylene-carbonate, or polypropylene suture. The macroscopic and histologic appearance of the incisions was compared. Polypropylene suture compared favorably to glycolide, ɛ-caprolacton, and trimethylene-carbonate suture for closure of skin incisions in cats.     

Business model for developing strategies of forest cooperatives. Evidence from an emerging business environment in Greece

ABSTRACT

Forest cooperatives are essentially a form of entrepreneurship. However, they are confronted by various problems and they cannot pay enough attention to value creation. The aim of this paper is twofold: (a) the identification of the structural factors supporting the function of Greek forest cooperatives and the exploration of the possibilities of applying business model innovation to them; (b) the investigation of how the development of an integrated business model can help cooperatives stay ahead in the innovation game, while securing sustainability. By applying business modeling procedures to the forest cooperatives of the Region of Thessaly (Greece) this paper presents, the implementation of innovative development strategy, within the current legislative framework. Results show that the business model approach gives them the ability to develop a shared vision for value creation and delivering through the establishment of a framework related to sustainable forest management based on creation of bonds for achieving a win-win strategy, satisfying the increasing needs for innovative forest-based products, which constitutes a challenge for the sustainable management of forests. We argue that this is the first time this approach has been made regarding forest cooperatives in Greece in relation to the emerging parameters of the general business environment.     

Long-term follow-up of spinal segmental stabilization for surgical treatment of dorsal hemivertebrae associated with kyphosis in brachycephalic dogs

The aim of this study is to report chronic complications (> 2 mo after surgery) following spinal segmental stabilization (SSS) to treat myelopathy associated with thoracic congenital vertebral malformations in brachycephalic dogs. Follow-up medical records (years 2006 to 2020) of 12 cases that underwent SSS at 3 university hospitals were retrieved and analyzed with a minimum follow-up period of 1 y. Five dogs showed no chronic complications and 7 dogs had chronic complications which are reported here. This case series demonstrates that the rate of chronic complications associated with SSS was high (58%) but most of these were minor and did not require revision surgery.     

Two-way coupling of unsaturated-saturated flow by integrating the SWAT and MODFLOW models with application in an irrigation district in arid region of West China

This paper presents the realization of two-way coupling of the unsaturated-saturated flow interactions of the SWAT2000 and MODFLOW96 models on the basis of the integrated surface/groundwater model SWATMOD99, and its application in Hetao Irrigation District (HID), Inner Mongolia, China. Major revisions and enhancements were made to the SWAT2000 and MODFLOW models for simulating the detailed hydrologic budget and coupled unsaturated and saturated interactions, and irrigation canal hydrology for the HID. The simulation results of seasonal groundwater recharge to and evaporate from the shallow groundwater, and the annual water budget over the district are presented and discussed. The results implied the necessity of two-way coupling of the unsaturated-saturated interactions when groundwater is shallow, and the feasibility of making comprehensive use of the information coming from both the surface water and groundwater models to make a more physically-based assessment of the coupled interactions.     

Response of phosphorus fractions to land-use change followed by long-term fertilization in a sub-alpine humid soil of Qinghai–Tibet plateau

Purpose

Identification of phosphorus (P) species is essential to understand the transformation and availability of P in soil. However, P species as affected by land use change along with fertilization has received little attention in a sub-alpine humid soil of Tibet plateau.

Materials and methods

In this study, we investigated the changes in P species using Hedley sequential fractionation and liquid-state ³¹P-NMR spectroscopy in soils under meadow (M) and under cropland with (CF) or without (CNF) long-term fertilization for 26 years in a sub-alpine cold-humid region in Qinghai–Tibet plateau.

Results and discussion

Land-use change and long-term fertilization affected the status and fractions of P. A strong mineralization of organic P (OP) was induced by losing protection of soil organic matter (SOM) and Fe and Al oxides during land-use change and resulted in an increase of orthophosphate (from 56.49 mg kg^?1 in M soils to 130.07 mg kg^?1 in CNF soils) and great decreases of orthophosphate diesters (diester-P, from 23.35 mg kg^?1 in M soils to 10.68 mg kg^?1 in CNF soils) and monoesters (from 336.04 mg kg^?1 in M soils to 73.26 mg kg^?1 in CNF soils). Long-term fertilization boosted P supply but failed to reclaim soil diester-P (from 10.68 mg kg^?1 in CNF soils to 7.79 mg kg^?1 in CF soils). This may be due to the fragile protection from the combination of SOM with diester-P when long-term fertilization had only improved SOM in a slight extent.

Conclusions

These results suggest that SOM plays an important role in the soil P cycling and prevents OP mineralization and losses from soil. It is recommended that optimization of soil nutrient management integrated with SOM was required to improve the P use efficiency for the development of sustainable agriculture.

     

Determining the infection status of a herd

This article presents hierarchical models for determining infection status and prevalence of infection within a herd given a hypergeometric or binomial sample of animals that have been screened with an imperfect test. Expert prior information on the infection status of the herd, diagnostic test accuracy, and herd prevalence is incorporated into the model. Posterior probabilities versus prior probabilities of infection are presented in the novel form of a curve, summarizing the probability of infection over a range of possible prior probability values. We demonstrate the model with serologic data for Mycobacterium paratuberculosis (Johne’s disease) in dairy herds.