Rate Of Exchange Research Articles

Logjam Characteristics as Drivers of Transient Storage in Headwater Streams

AbstractLogjams in a stream create backwater conditions and locally force water to flow through the streambed, creating zones of transient storage within the surface and subsurface of a stream. We investigate the relative importance of logjam distribution density, logjam permeability, and discharge on transient storage in a simplified experimental channel. We use physical flume experiments in which we inject a salt tracer, monitor fluid conductivity breakthrough curves in surface water, and determine breakthrough‐curve skewness to characterize transient storage. We then develop a companion numerical model in HydroGeoSphere to reveal flow paths through the subsurface (or hyporheic zone) that contribute to some of the longest transient‐storage timescales. In both the flume experiments and numerical simulations, we observe backwater formation and an increase in hyporheic exchange at logjams. Observed complexities in transient storage behavior depend largely on surface water flow in the backwater zone. As expected, multiple successive logjams provide more pervasive hyporheic exchange by distributing the head drop at each jam, leading to distributed but shallow flow paths. Decreasing the permeability of a logjam or increasing the discharge both facilitate greater surface water storage and volumetric rate of hyporheic exchange. Understanding how logjam characteristics affect solute transport through both the channel and hyporheic zone has important management implications for rivers in forested, or historically forested, environments.

Hydrogen Isotope Exchange between Trichloroethene and Water under Mild Environmental Conditions─Implications for the Use of Hydrogen CSIA in Contaminated Site Assessment

Trichloroethylene (TCE) is a key legacy environmental contaminant and a major target for contaminant remediation projects. Hydrogen compound-specific isotope analysis (CSIA) of halocarbons is a relatively recent technique, predominantly used as a line of evidence for apportionment of TCE sources. To date, no published data addressed the potential for hydrogen exchange between TCE and hydroxide in a water solution under typical groundwater pH conditions. In this study, we determined the pH- and temperature-dependent rates of exchange in controlled experiments to constrain the scope of applications of hydrogen CSIA at field sites contaminated by TCE. Relatively high rates of the exchange were associated with above-neutral pH typical of carbonate aquifers (half-lives of years to decades) and slower, but not negligible, rates were associated with sub-neutral pH. Hydrogen exchange alters the hydrogen isotope composition of TCE in solution, masking initial source signatures or degradation signatures over environmentally relevant time scales. In effect, the TCE–water exchange restricts the classical applications of hydrogen CSIA data to a subset of distinctly acidic environments. On the other hand, as the rates of the exchange can be predicted for specific combinations of pH and temperature, the process could be potentially utilized in age-dating of TCE contamination.

Gas exchange patterns for a small, stored-grain insect pest, Tribolium castaneum.

Insects breathe using one or a combination of three gas exchange patterns; continuous, cyclic and discontinuous, which vary in their rates of exchange of oxygen, carbon dioxide and water. In general, there is a trade-off between lowering gas exchange using discontinuous exchange that limits water loss at the cost of lower metabolic rate. These patterns and hypotheses for the evolution of discontinuous exchange have been examined for relatively large insects (>20 mg) over relatively short periods (<4 h), but smaller insects and longer time periods have yet to be examined. We measured gas exchange patterns and metabolic rates for adults of a small insect pest of grain, the red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae), using flow-through respirometry in dry air for 48 h. All adults survived the desiccating measurement period; initially they used continuous gas exchange, then after 24 h switched to cyclic gas exchange with a 27% decrease in metabolic rate, and then after 48 h switched to discontinuous gas exchange with increased interburst duration and further decrease in metabolic rate. The successful use of the Qubit, a lower cost and so more common gas analyser, to measure respiration in the very small T. castaneum, may prompt more flow-through respirometry studies of small insects. Running such studies over long durations may help to better understand the evolution of respiration physiology and thus suggest new methods of pest management.

Antidepressant Poisoning Trends in Pediatric Intensive Care: A Comparative Study of New- and Old-Generation Antidepressants.

This study aimed to compare the frequency, clinical findings, treatment practices, and outcomes of toxicity to old-generation (OG) and new-generation (NG) antidepressants in our pediatric intensive care unit (PICU) by year-to-year. The study included patients hospitalized for antidepressant poisoning during the 11-year period of January 2010 through December 2020. Antidepressants were classified as OG and NG. The groups were compared in terms of patient demographic characteristics, type of poisoning (accidental/suicidal), clinical findings, supportive and extracorporeal treatments received, and outcomes. The study included 58 patients (NG, n = 30; OG, n = 28). The median age of the patients was 178 months (range, 13.6-215 months) and 47 patients (81%) were female. Patients admitted for only antidepressant poisoning constituted 13.3% of all poisoning cases (58/436). Of these, 22 cases (37.9%) were accidental and 36 (62.3%) were suicidal. The most common cause of poisoning was amitriptyline (24/28) in the OG group and sertraline (13/30) in the NG group. Neurological symptoms were significantly more common in the OG group (76.2% vs 23.8%), while gastrointestinal involvement was more common in the NG group (82% vs 18%; P = 0.001 and P = 0.026, respectively). Old-generation antidepressant poisoning was associated with more frequent intubation (4 vs 0 patients, P = 0.048) and longer length of PICU stay (median, 1 day [range, 1-8] vs 1 day [range, 1-4], P = 0.019). Rates of therapeutic plasma exchange and intravenous lipid emulsion therapy did not differ ( P = 0.483 and P = 0.229, respectively). In poisoned patients, proper evaluation and management of patients requiring PICU admission are vital for favorable patient outcomes.

Mark-recapture estimates of seasonal abundance and survivorship for bottlenose dolphins (Tursiops truncatus) near Charleston, South Carolina, USA

The stock structure of western North Atlantic bottlenose dolphins (Tursiops truncatus) is complex, with seasonally migratory stocks often overlapping with year-round resident stocks. High rates of exchange between northernmost sites have been documented but movement and seasonal fluctuation in abundance among sites along the southern portion of the US Atlantic coast is not well understood. To better understand seasonal abundance, a three-year mark-recapture study of bottlenose dolphins in coastal and estuarine waters near Charleston, South Carolina, USA was conducted. A robust design was employed in order to minimise bias and more precisely determine seasonal estimates of abundance and concurrently examine temporary immigration/emigration and survivorship. Systematic boat-based surveys were carried out (n = 192) from January 2004 to December 2006. The entire study area was surveyed one week per month; an additional survey was conducted in the months in which seasonal abundance was estimated: January (winter), April (spring), July (summer) and October (autumn). Standard photo-identification techniques were used to accumulate sightings of 521 distinctively marked dolphins, 65% of which were sighted more than once. Pollock’s robust design was applied using MARK and the ensuing abundance estimates were adjusted for the seasonal proportion of unmarked dolphins (ranging from 0.27 to 0.40) in the population. Estimates ranged from 364 (95% CI = 305–442) in January 2004 to 910 (95% CI = 819–1018) in October 2006. Summer abundance estimates were consistently greater than those from winter months, although estimates varied considerably among years. The same model was used to calculate an annual survival rate estimate of 0.951 (95% CI = 0.882–1.00) for marked individuals within the population. A high degree of transience, demonstrated by seasonal influxes of single-sighted individuals, made it difficult to differentiate between mortality and permanent emigration. The results support the occurrence of three distinct dolphin groups found in Charleston waters: year-round residents; seasonal residents; and transients. Reporting abundance and survivorship estimates together is useful in explaining and validating results for populations in which transient individuals occur. These results provide important information for stock and viability assessment of coastal bottlenose dolphins in the western North Atlantic.

A Field Evaluation of Sodium Silicate and Bacillus subtilis on the Growth and Yield of Bananas following Fusarium Wilt Disease Infection

A field investigation was conducted in a Fusarium-infected area to evaluate the effectiveness of silicate compounds with antagonist bacteria on morpho-physiological growth performance in bananas. The roots of banana plants were treated by drenching the soil with four different treatments: control (without any treatment), CBZ (Carbendazim fungicide alone), SS + BS (integration sodium silicate with Bacillus subtilis), and CBZ + SS + BS (integration CBZ, SS, and BS). All treatments were arranged in a randomized complete block design with four replications. The results confirm that plant height, pseudo-stem diameter, and canopy diameter markedly increased from weeks 2 to 10 after transplantation. Amendment with these elements induced a higher total chlorophyll content, which contributed to the increased rate of leaf gas exchange and biochemical changes for controlling Fusarium wilt disease infection. From these findings, the CBZ + SS + BS application in the farm had significantly reduced disease incidence by 16.07% and disease severity by 14.28%. The same treatment achieved the greatest disease reduction by 63.05%. Therefore, the integration between CBZ + SS + BS had good significant effects in controlling Fusarium wilt disease and enhanced the morpho-physiological growth performance with an average yield production of about 24.72 kg per fruit bunch.

HYDROGEOLOGICAL CHARACTERIZATION OF LOCAL GROUNDWATER RESERVOIRS IN THE KŁODZKO LAND (SUDETES - SW POLAND) BASED ON AN ANALYSIS OF THE DISCHARGES OF SPRINGS

The hydrogeological characteristics of the two types of local groundwater reservoirs found in the Kłodzko Land (Sudetes) have been made based on the analysis of the discharge of springs in Szczytna and Różanka. In the first of these spring discharge points, water flows out of Upper Cretaceous sandstones and mudstones. The other spring is associated with fractured and weathered mica schists and gneisses. The Różanka spring characterized by greater discharge variability than the fissured porous outflow in Szczytna. The latter one, due to the slower rate of water filtration in the rock medium, belongs to stable springs in terms of discharge. The local groundwater reservoir located in sedimentary rocks characterized by a much higher value of the groundwater volume stored (264,000 m3) than the reservoir consisting of weathered and fractured crystalline rocks (1,918 m3). In the case of the reservoir draining by Szczytna spring, the rate of groundwater exchange in the active zones is about 66 weeks. A distinctly shorter time (12 weeks) is necessary to exchange water in the fractured crystalline bedrock. The hydraulic conductivity for the aquifers in Szczytna and Różanka, calculated based on the recession coefficient, differ substantially from each other. They are 4.64 and 24.9 m/d, respectively.

Experimental investigations into thermal performance of phase change emulsion in a fin-and-tube heat exchanger

AbstractPhase change emulsions (PCMEs) are always identified as potential working fluids that could be used to reduce circulating pump energy consumption in chill water air conditioning systems. But how PCME behaves in a fin-and-tube heat exchanger is still unclear, which limited the application of such material. The paper focused on experimental studies of performance of a novel PCME, named as PCE-10, in a fin-and-tube heat exchanger. The research analyzed heat transfer and flow behavior in fin-and-tube heat exchangers and the experimental results are compared with numerical studies published. Both studies showed that PCE-10 had its advantages as a cold storage medium, as PCE-10 did help to improve the heat transfer rate of heat exchanger by factor of 1.1–1.3 at the same flow rate compared with water.

Interface resistance of biomolecular condensates.

A hallmark of biomolecular condensates formed via liquid-liquid phase separation is the dynamic exchange of condensate components with the surroundings. Such material exchange can be key to condensate function, as the rate of component exchange can impact biochemical reaction rates in the condensates, the speed of response of condensates to a changing environment, and their number and sizes. How is this exchange rate controlled? Intuitively, this rate can be limited by the flux of materials from the dilute phase or by the speed of mixing inside the dense phase. Surprisingly, recent experiments suggest that this rate can also be limited by the dynamics of molecules at the droplet interface, implying the existence of an “interface resistance”. Here, we combined theory and simulation to show that an interface resistance can arise when incident molecules contact the interface without entering the dense phase. We find that such “bouncing” occurs for incident molecules that are capable of self-collapse into a non-sticking conformation. Our work highlights the underappreciated role of interface resistance in condensate exchange dynamics, with implications for natural and synthetic systems.

Facile and dynamic cleavage of every iron–sulfide bond in cuboidal iron–sulfur clusters

Nature employs weak-field metalloclusters to support a wide range of biological processes. The most ubiquitous metalloclusters are the cuboidal Fe-S clusters, which are comprised of Fe sites with locally high-spin electronic configurations. Such configurations enhance rates of ligand exchange and imbue the clusters with a degree of structural plasticity that is increasingly thought to be functionally relevant. Here, we examine this phenomenon using isotope tracing experiments. Specifically, we demonstrate that synthetic [Fe4S4] and [MoFe3S4] clusters exchange their Fe atoms with Fe2+ ions dissolved in solution, a process that involves the reversible cleavage and reformation of every Fe-S bond in the cluster core. This exchange is facile-in most cases occurring at room temperature on the timescale of minutes-and documented over a range of cluster core oxidation states and terminal ligation patterns. In addition to suggesting a highly dynamic picture of cluster structure, these results provide a method for isotopically labeling pre-formed clusters with spin-active nuclei, such as 57Fe. Such a protocol is demonstrated for the radical S-adenosyl-l-methionine enzyme, RlmN.

Methane and nitrous oxide fluxes from clonal eucalyptus forests in different spacing arrangements

Abstract Although Eucalyptus is the most commonly cultivated genus in Brazil, more information is needed on how these forests can act as a sink for greenhouse gases. This study assessed the potential greenhouse gas (GHG) mitigation of eucalyptus forests by quantifying both the seasonal rates of exchange of methane (CH4) and nitrous oxide (N2O) gases at the soil–atmosphere interface and their relationships with soil variables (moisture, temperature and physicochemical attributes). Soil organic carbon sequestration rate was used together with soil GHG emission to estimate net global warming potential. This study was conducted at an experimental forestry station in the south-central region of the state of São Paulo, Brazil. No differences were found between treatments in the seasonal fluxes of N2O and CH4, which may have resulted from similar soil properties, particularly bulk density and nitrate (NO3−) contents. CH4 flux dynamics were mainly controlled by the concentrations of ammonium (NH4+) in the soil. In all treatments, the soil acted as a continuous sink for CH4, absorbing it at an average rate of −65 μg C m−2 h−1, which was higher than the results of other studies conducted in native areas of the Cerrado biome and planted forests. However, although CH4 removal helped offset greenhouse gas emissions, net emissions were seen in most treatments due to N2O emissions in greater magnitude and soil carbon losses.

Let's Talk about Sex… and ADHD: Findings from an Anonymous Online Survey.

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by inattention, hyperactivity and impulsivity. A dearth of studies have investigated psychosexuality in this population, often with few (predominantly male) participants. We recruited individuals with and without ADHD via an anonymous online survey distributed electronically by ADHD support organizations and social media. We investigated sexual history; interests and practices; and relationships. Of 1392 respondents, we classified an 'ADHD' group (n = 541; 30.5% male) and compared them to individuals of similar ages without ADHD, ('Other' group; n = 851; 37.6% male). The ADHD group (both males and females) had a significantly higher preference for same-sex or either-sex partners; and higher rates of electronic sexual exchanges, masturbation, and sexually transmitted diseases. They were more adventurous in sexual interests and practices and substantially less satisfied with their partners, both sexually and generally. Within the ADHD group, significant sex differences emerged: females had younger onset of sexual activities, used contraception less frequently, had more sexual partners and practiced more infidelity. Sexual interests differed between the sexes, but females more commonly acted on them, whereas males did not. Findings suggest both sexes engage in risky sexual behaviors, perhaps driven by impulsivity, but risk is substantially greater for females with ADHD.

Experimental and Numerical Simulations of Climatic Loads in Insulating Glass Units by Controlled Change of Pressure in the Gap

Insulating glass units (IGUs) are building components that show a particular structural behavior. Although such structures have many advantages from the point of view of thermal protection of buildings, they show particular structural behavior under climatic loads. The inability to equalize the pressure with the surrounding atmospheric air causes over- or under-pressure inside the gap. The phenomenon may result in the deformation of the panes under the influence of temporary or cyclical changes in weather conditions. This article presents the results of an experimental campaign with a representative IGU sample. The sample had dimensions of 500 mm × 500 mm and was composed of two 6 mm glass panes and a 16 mm wide spacer. The experiments were carried out using a rarely used methodology by inducing a controlled pressure change in the gap. Subsequently, analytical and numerical models were developed, and the results were compared with the experimental findings. The study found that the rapid injection/withdrawal of gas into/from the gap causes a sudden change in the pressure inside the gap, which decreases in absolute value and stabilizes after a few seconds. The decrease, on average, of 7% is due to adiabatic effects resulting from the high rate of gas exchange. The results from the numerical and analytical studies underestimate the pressure difference values obtained in the tests by an average of 8%. In terms of deflections and stresses, the results overestimate the experiments by 16% and 32%, respectively. This finding indicates the presence of a partial rotational restrain of the panes’ edges, which some researchers have also reported. This effect is usually ignored in engineering practice.

Effect of bio calcium feed additive on the biochemical status of quail blood

The authors conducted the study based on the experimental quail farm SRDIAH SFSCA RAS (Siberian Research and Design Institute of Animal Husbandry Siberian Federal Scientific Center for Agrobiotechnology of the Russian Academy of Sciences) and at the Department of Obstetrics, Anatomy, and Histology of the Novosibirsk State Agrarian University. The study aims to change the content of micro- and macroelements in the blood of quails of the Japanese meat breed when using the Biocalcium feed additive. The productivity of animals depends on their health and is determined by their metabolism level. Birds, unlike other animals, have an intensive mineral metabolism.Calcium and phosphorus are two biologically active components with many functions that determine ana- and catabolic processes. When oviposition begins, the calcium and phosphorus concentration in chickens’ blood serum increases. But the rate of exchange of these macronutrients is determined by the activity of oviposition, so control over the content of these substances is relevant. Indicator enzymes that perform certain intracellular functions and enter the blood from the tissues are informative indicators for assessing metabolism. Using the activity index of alkaline phosphatase is reasonable to evaluate calcium-phosphorus metabolism. Using the feed additive Biocalcium in the blood of quail of the experimental group increased the calcium concentration by 0.2%. If we talk about zinc, iron, and magnesium indicators, they increased by 0.1-0.3%. It was also found that the introduction of fiber in feed rations had a definite effect on protein metabolism. During the experiment, it was found that the feed additive based on Siberian silver fir substrate Biocalcium has no apparent negative impact on the body of the quail. The additive is effective at a late stage of rearing. The authors note an improvement in metabolism, the mineral composition of the blood is normalized; hematopoiesis is stimulated without changing the stability of hematopoiesis and the constancy of the blood composition due to the introduction of this feed additive into the diet of birds.

Equilibrium Ca isotope fractionation and the rates of isotope exchange in the calcite-fluid and aragonite-fluid systems at 25 °C

The Ca isotope composition of calcite and aragonite can provide insights into their formation conditions. The accurate interpretation of the Ca isotope composition of natural samples, however, requires precise knowledge of the equilibrium Ca isotope fractionation between the solid and fluid phases. In this study, the three-isotope method with 42Ca, 43Ca and 44Ca has been used to estimate the equilibrium isotope fractionation of Ca between the CaCO3 minerals calcite and aragonite and the Ca2+ aquo ion. Reactive fluids were enriched with 43Ca and equilibrated with synthetic calcite and aragonite of natural Ca isotope distribution up to 3745 h at 25°C. The isotopic composition of solids and fluids was measured using MC-ICP-MS and the estimated equilibrium fractionation for calcite-Ca2+(aq) and aragonite-Ca2+(aq) was Δ44/42Casolid-fluid=−0.02±0.13‰ and −0.80±0.10‰, respectively. Textural observations of the reacted solids suggest that isotope equilibration in aragonite experiments occurs via extensive Ostwald ripening, yielding large crystalline needles at the end of the experiments. In contrast, calcite did not exhibit an observable increase in size during the course of the experiments. Isotope exchange rates in the case of calcite are similar to those reported in previous studies and ∼4 orders of magnitude lower than the far-from-equilibrium calcite dissolution rate. Calcium isotope exchange rates for aragonite are more rapid than calcite driven by a greater extent of Ostwald ripening occurring via dissolution/precipitation reactions. The results of this study suggest that the Ca isotope compositions of calcite and aragonite crystals in chemical equilibrium, but isotope disequilibrium, with natural fluids could be significantly altered without overt evidence of diagenesis, especially in the case of calcite. The extent to which Ca isotope compositions are altered, however, would depend strongly on the environmental conditions, such as fluid:solid ratio and permeability of the solid facilitating fluid transport.

Dynamic heat transfer characteristics of ice storage in smooth-tube and corrugated-tube heat exchangers

The ice storage system is one of the most promising techniques for flexibility enhancement of building cooling load. In this paper, the performances of smooth-tube and corrugated-tube heat exchangers for ice storage are compared by experiments and numerical simulation. The heat transfer process of the ice storage and melting within the heat exchangers is numerically analyzed used Python. The fast one-dimensional numerical model is verified by the experimental results. The temperature variation of the heat transfer fluid (HTF) in the corrugated tube is analyzed and compared with that in the smooth tube. The results show that under the same conditions, the ice storage duration of the corrugated tube is shortened by 25% and the melting duration is shortened by 16% compared with those of the smooth tube. During the ice storage process, the temperature difference between the inlet and outlet of the heat transfer fluid in the corrugated tube is 0.4 °C less than that of the smooth tube on average. The temperature change rate is 30% faster than that of the smooth tube. During the melting process, the temperature difference between the inlet and outlet of the heat transfer fluid in the corrugated tube is 0.1 °C higher than that of the smooth tube on average, and the temperature change rate of corrugated-tube heat exchanger is 2.5 times and 9 times faster than that of the smooth tube during the ice-storage and melting process. The corrugated-tube heat exchanger has superior performances in ice storage system in the comparison with the smooth-tube heat exchanger.

Assessment of Biometric Parameters and Health of Canna’s Cultivars as Plant Useful in Phytoremediation of Degraded Agrocenoses

Recently, the ecological awareness of society and the need to take care of our surroundings and the natural environment has significantly increased. There is also an urgent problem of searching for new, environmentally friendly techniques for its purification (soil, ground and surface waters, sewage sludge and air) with the use of living organisms, especially higher plants. One plant species investigated for phytoremediation is canna. Ten varieties of canna, grown on degraded and garden soil, were tested in this respect. The disease index and species composition of fungi inhabiting its organs, growth dynamics, parameters of photosynthesis and gas exchange were determined. The conducted research showed that cannas are able to satisfactorily grow even in seemingly unfavorable soil conditions with its strong degradation. Among a total of 24 species of fungi obtained from its organs, genus Fusarium, considered as pathogenic for canna, Alternaria alternata, and, less frequently, Thanatephorus cucumeris and Botrytis cinerea, dominated. The cultivars ‘Picasso’, ‘Cherry Red’, ‘President’ and ‘La Boheme’ had lower rates of photosynthesis and gas exchange than the least affected ‘Botanica’, ‘Wyoming’, ‘Robert Kemp’ and ‘Lucifer’ cultivars. Those turned out to be the most beneficial and they can be recommended for cultivation on strongly degenerated soils.

Biofilm Lifestyle in Recurrent Urinary Tract Infections.

Urinary tract infections (UTIs) represent one of the most common infections that are frequently encountered in health care facilities. One of the main mechanisms used by bacteria that allows them to survive hostile environments is biofilm formation. Biofilms are closed bacterial communities that offer protection and safe hiding, allowing bacteria to evade host defenses and hide from the reach of antibiotics. Inside biofilm communities, bacteria show an increased rate of horizontal gene transfer and exchange of resistance and virulence genes. Additionally, bacterial communication within the biofilm allows them to orchestrate the expression of virulence genes, which further cements the infestation and increases the invasiveness of the infection. These facts stress the necessity of continuously updating our information and understanding of the etiology, pathogenesis, and eradication methods of this growing public health concern. This review seeks to understand the role of biofilm formation in recurrent urinary tact infections by outlining the mechanisms underlying biofilm formation in different uropathogens, in addition to shedding light on some biofilm eradication strategies.

PUBLIC EXPENDITURE AND INFLATION RATE IN NIGERIA

This paper examined the relationship between inflation and government spending in Nigeria for the period 1990 to 2022. The study utilized Augmented Dickey-Fuller unit root test, Johansen cointegration; Granger causality Test and Vector Error Correction Model (VECM) approaches. The secondary data variables in consideration are government spending (GEXP), inflation rate (INF), exchange rate (EXR) and broad money supply (MS2) and they were soured from CBN Statistical Bulletins. Although the unit root tests showed that the variables possessed a unit root problem at their level but freed from this at their first order of integration, the Johansen co-integration result showed that the variables were co-integrated. The result indicated that there is a long-run and shortrun bilateral causal relationship between inflation and government spending. The regression estimate based on the short run and long run VECM showed that inflation rate has a positive significant influence on government spending in Nigeria over the study period. Money supply is positively related with government spending in the recent years. Meanwhile exchange rate over the study periods showed a significant reduction in government spending in Nigeria in the recent years because a rise in exchanger rate reduced the value of naira and hence affect the government expenditure negatively.

The unfortunate dearth of judicial precedent in transfer pricing continues

Despite what could be hailed as the first two transfer pricing cases in South Africa, the unfortunate dearth of judicial precedent in South Africa regrettably continues. Transfer pricing is one of the most complex areas of tax alongside provisions dealing with controlled foreign companies, foreign exchange gains and losses, currency conversions, financial instruments, and corporate reorganisations. In fact, as the list goes on, it is just more apposite to say ‘tax is complex’, period. With regard to transfer pricing in particular, the complexity is amplified by the fact that transfer pricing is not even tax per se. It is an economic allocation of contribution through the value chain. It is through transfer pricing that each contributor in the value chain gets an adequate return for their contribution in the value chain. Once that allocation is complete, the tax provisions are applied to the returns of each contributor according to the tax laws of the countries in which they are taxable. A transfer price is a price set by a taxpayer when selling to, buying from or sharing resources with a related person. A transfer price is contrasted with a market price, which is the price set in the marketplace for the transfer of goods and services between unrelated persons where each party strives to get the utmost possible benefit from the transaction (see Arnold &amp; McIntyre, International Tax Primer (Kluwer Law International 2002) 55; Danzinger, International Income Tax (Butterworths 1991) 303–307). Transfer prices are not negotiated in a free open market and as such have the propensity to deviate from prices agreed upon by non-related trading partners in comparable transactions under the same circumstances (Oguttu, International Tax Law: Offshore Tax Avoidance in South Africa (Juta 2015) 213). Unless prevented from doing so, related persons engaged in cross-border transactions can avoid the income taxes of a country through a manipulation of prices, mainly by shifting profits to low tax countries and expenses to high tax countries. To combat this, tax authorities across the globe have the power to adjust, in appropriate cases, the transfer prices set by related persons (Arnold &amp; McIntyre, (Kluwer 2002) 55. In what can be welcomed as the first transfer pricing case in the South African courts, the South Johannesburg High Court had an opportunity to decide on the applicability of s 31(7) of the Income Tax Act 58 of 1962 (‘the Act’; any reference to a section or subsection are to the Act, unless otherwise stated, or the context indicates otherwise) to a debt owed by a foreign company to a South African company. The applicable provision excludes debt instruments that contain core characteristics of debt instruments from the application of transfer pricing provisions. In the second case, the same court missed out on an opportunity to gauge the legitimacy of the revenue collector to use s 31(2) of the Act to adjust prices charged between a taxpayer and third parties that are not related to the taxpayer.