Degree Of Variability Research Articles

Dynamic event tree analysis of a severe accident sequence in a boiling water reactor experiencing a cyberattack scenario

Over the last decade, probabilistic risk assessment (PRA) for nuclear power plants shifted its focus toward simulation-based methods of evaluating safety and risk aspects. Classical reliability modeling based on static Boolean structures does not capture the dynamic nature of plants experiencing accident sequences. Dynamic PRA extends conventional reliability modeling, adding a higher degree of variability to events occuring during accident sequences. This paper demonstrates the capability of a new dynamic event tree (DET) analysis tool applicable to severe accident sequences. A cyberattack was assumed to penetrate the instrumentation system of a boiling water reactor during its hot shutdown phase, altering the thermal–hydraulic variables being processed. The analysis focused on scenarios that lead to the core being uncovered, in which the peak cladding temperature is reached due to the disabling of the cooling systems. A limiting surface is defined, associating the cyberattack timing to the recovery time limit that would compromise the core integrity.

Survey on the usage of therapeutic erythrocytapheresis in transfusion services in Italy for the treatment of polycythemia vera, secondary erythrocytosis and hemochromatosis.

IntroductionErythrocytapheresis, an apheresis treatment which selectively removes red blood cells, is an alternative to therapeutic phlebotomy, over which it has several advantages.Actually there is a high degree of variability in the use of this treatment. This prompted SIdEM (Italian Society of Hemapheresis and Cell Manipulation) to conduct a survey on the use of erythrocytapheresis in the Italian Transfusion Services. The purpose is to monitor this activity in the treatment of Polycythemia Vera (pv), secondary erythrocytosis and hemochromatosis. Materials and methodsA data collection file was sent to the SIdEM regional delegates who, in turn, involved the Transfusion Centers in the areas they cover. The data collected were processed on a Microsoft Excel spreadsheet. Results75 centers from 14 Italian regions responded to the Survey: 36 centers (48 %) use erythrocytapheresis (35 centers perform therapeutic apheresis and 1 center only donor apheresis), 39 centers (52 %) do not (15 centers perform therapeutic apheresis, 18 centers only donor apheresis and 6 centers do not perform either therapeutic apheresis or donor apheresis).Although most centers have a substantially uniform attitude concerning the indications for which erythrocytapheresis is used, the survey shows that there are still differences more evident in the treatment of secondary erythrocytosis than in the treatment of pv or hemochromatosis. ConclusionsThis survey has been useful to document the current Italian reality and to raise awareness about the need for improvement in optimizing and standardizing the use of a therapy with a great potential to exploit properly.

Seroprevalence and Genotypic Distribution Patterns of Hepatitis C Virus among Infected Patients from Sulaimaniyah Province: Iraq

Background: The hepatitis C virus (HCV) is a prevalent cause of liver illness. The virus displays a high degree of genetic variability, with documented geographical differences in genotype predominance.
 
 Objective: This study aimed to determine the prevalence of HCV genotypes among people who lived in Sulaimaniyah province, Kurdistan region of Iraq.
 
 Patients and Methods: Blood samples were collected from 229 individuals identified as having a confirmed positive HCV antibody and who had been referred to the Public Health Laboratory in Sulaimaniyah city by medical professionals for genotyping from July 2021 to December 2022. Following the extraction of the viral RNA, a PCR-based genotyping kit was used to identify the HCV genotype.
 
 Results: The most prevalent genotype was GT1a (31.6%), followed by GT1 and GT4 (23.6%) and then GT1b (7.9%). Mixed genotypes were observed in 10.4% of samples. Males were affected mainly by HCV (58.5%) than females (41.5%). The frequency of GT1a was higher in males (32.1%) compared to females (30.5%). On the other hand, males exhibited a more excellent distribution of GT4 and GT1 than females, while GT1b and GT5 were observed more in females than males. Among mixed genotypes, GT5 or 6 was the most prevalent infection type (no.=8, 3.5%), while GT1a, 3 reported the lowest rate (no.=1, 0.4%).
 
 Conclusion: This study assesses the HCV genotype distribution among infected HCV patients in Sulaimaniyah, which is distinct from the prevalent distribution in Iraq and Middle Eastern Arab nations, but it is equivalent to the distribution worldwide.

Molecular Characterization of Fluted Pumpkin Landraces in South East Nigeria

The fluted pumpkin Telfairia occidentalis (Hook F.) is a very important vegetable, popularly cultivated in South Eastern Nigeria for its economic value and its role in nutrition. It exhibits a high degree of interspecies variability and as such enhances biodiversity. Twenty landraces of fluted pumpkin were collected from five States in southern Nigeria which include; Anambra, Ogun, Lagos, Ondo and Enugu State. The landraces were grown in the Botanical Garden of Lagos State University, Ojo during the rainy season of 2013 for phenotypic screening to determine genetic divergence. The experiment was laid out in randomized block design with three replications. Genetic characterization was conducted in the biotech lab of the national institute of medical research (NIMER). The genomic DNA was extracted from the samples and extracted DNA samples were amplified through the PCR techniques using four primers (RAPD – 01, OPR-02, OPC – 04 and SCAR-1 primer) to access diversity among the genotypes. The result reveals a huge genetic divergence among the genotypes studied. The genotypes were grouped into five clusters based on a 2.0(20%) level of similarity by single linkage cluster analysis, which agrees with morphological data, each containing fluted pumpkin genotypes sharing common properties and being similar to one another.

Accuracy of non-contact semiconductor X-ray analyzer for quality assurance in intraoral radiography: a comparison with ionization chamber dosimeter.

The aim of the present study was to evaluate the accuracy of a non-contact semiconductor X-ray analyzer for quality assurance in intraoral radiography, especially a comparison with an ionization chamber dosimeter. Intraoral radiography was performed with intraoral X-ray unit using the dental protocol at our hospital: tube voltage, 70kV; tube current, 7mA. Accuracy of dose and half-value layer (HVL) measurements was analyzed with a non-contact semiconductor X-ray analyzer and an ionization chamber dosimeter. Stability of the semiconductor sensor, effect of scattered radiation, and comparison of measured HVL between the ionization chamber and the semiconductor sensor were analyzed in this study. The values with the semiconductor sensor were tube voltage: 70.3 ± 0.2 kVp (degree of variability: 0.28%), dose: 454.1 ± 12.3μGy (degree of variability: 2.7%), and HVL: 1.91 ± 0.02 mmAl (degree of variability: 1.0%). With collimator, the dose with the semiconductor sensor and the ionization chamber decreased by 2.3 μ Gy and 5.2 μ Gy, respectively. The measured HVL of the semiconductor dosimeter was more than that of ionization chamber, and the semiconductor dosimeter was less than ionization chamber in variation of between without and with collimator. This study indicated the accuracy of a non-contact semiconductor X-ray analyzer for quality assurance in intraoral radiography, especially a comparison with an ionization chamber dosimeter. The semiconductor sensor can be useful for quality assurance in intraoral radiography.

Analyzing the informative value of alternative hazard indicators for monitoring drought hazard for human water supply and river ecosystems at the global scale

Abstract. Streamflow drought hazard indicators (SDHIs) are mostly lacking in large-scale drought early warning systems (DEWSs). This paper presents a new systematic approach for selecting and computing SDHIs for monitoring drought for human water supply from surface water and for river ecosystems. We recommend considering the habituation of the system at risk (e.g., a drinking water supplier or small-scale farmers in a specific region) to the streamflow regime when selecting indicators; i.e., users of the DEWSs should determine which type of deviation from normal (e.g., a certain interannual variability or a certain relative reduction of streamflow) the risk system of interest has become used to and adapted to. Distinguishing four indicator types, we classify indicators of drought magnitude (water anomaly during a predefined period) and severity (cumulated magnitude since the onset of the drought event) and specify the many relevant decisions that need to be made when computing SDHIs. Using the global hydrological model WaterGAP 2.2d, we quantify eight existing and three new SDHIs globally. For large-scale DEWSs based on the output of hydrological models, we recommend specific SDHIs that are suitable for assessing the drought hazard for (1) river ecosystems, (2) water users without access to large reservoirs, and (3) water users with access to large reservoirs, as well as being suitable for informing reservoir managers. These SDHIs include both drought magnitude and severity indicators that differ by the temporal averaging period and the habituation of the risk system to reduced water availability. Depending on the habituation of the risk system, drought magnitude is best quantified either by the relative deviation from the mean or by the return period of the streamflow value that is based on the frequency of non-exceedance. To compute the return period, we favor empirical percentiles over the standardized streamflow indicator as the former do not entail uncertainties due to the fitting of a probability distribution and can be computed for all streamflow time series. Drought severity should be assessed with indicators that imply habituation to a certain degree of interannual variability, to a certain reduction from mean streamflow, and to the ability to fulfill human water demand and environmental flows. Reservoir managers are best informed by the SDHIs of the grid cell that represents inflow into the reservoir. The DEWSs must provide comprehensive and clear explanations about the suitability of the provided indicators for specific risk systems.

Preferential Flow and Preferential Path Characteristics of the Typical Forests in the Karst Region of Southwest China

The ecological environment in the karst region of southwest China is fragile, and vegetation degradation is considered the main cause of this phenomenon. Vegetation growth is affected by preferential flow due to a large number of fissures and macropores in the soil. Therefore, the preferential flow and preferential paths in local typical vegetation need to be studied. The distribution and developmental characteristics of preferential flow and preferential paths in three typical local stands were obtained by conducting field staining tracer experiments and using image processing techniques. The results showed that there was preferential flow movement in the soil moisture of the local understorey and that there was a high degree of preferential flow development and high variability. The degree of preferential flow in several typical forests can be expressed, from highest to lowest, in the following order: secondary forests, Cupressus duclouxiana Hickel (Hickel., 1814) forest, and Pinus massoniana (Lamb., 1803) forest. The preferential paths in the soil were mainly distributed above 15 cm, and the number of preferential paths with a small influence radius was much greater than that with a large influence radius. The preferential paths with an influence radius of 2.5~5 mm accounted for the largest proportion. The total number of preferential paths in the P. massoniana forest was small. The preferential paths in the secondary and C. duclouxiana Hickel forests were similar in number, but the secondary forests had more preferential paths with a large influence radius. This study investigated the characteristics of preferential flow and preferential paths in the typical forests of the karst region in southwest China, and it can provide data and research directions for the study of hydrological processes in local forest vegetation.

‘You just have to stay awake and keep spying on the pipes’: Everyday experiences of piped water access in Tamale, Ghana

Analysis of access to water seems to focus mainly on the availability of or proximity to water supply infrastructure. The study of the lived experiences of accessing water from these infrastructures is increasingly gaining traction as a more useful way of demonstrating the complexities of urban water access in the global South. Through participant observations and in-depth interviews, this study explored the lived experiences of access to water from piped water network in Kpanvo and Katariga communities in Tamale, Ghana. The study found that piped water rationing in Tamale has created a default situation where households do not get regular and continuous supply of water. Prominently, there is a high degree of variability in terms of the experiences of water flow interruptions in the city. This gives rise to everyday practices in which residents stay awake to spy on the pipes, especially on days they anticipate piped water flows. In addition, piped water quality concerns and frequent disconnections due to nonpayment of service bills featured prominently in the everyday experiences of households in these communities. The study concludes that access to water ought to be understood not only in terms of physical access to piped water networks – critical as they may be – but also in terms of the lived experiences which characterize piped water access regimes at households and neighbourhood scales. These scales of analysis illuminate the everyday experiences of water access which would otherwise be concealed in generalized water access conditions in cities.

Three major chlorotype lineages in chamomile (Matricaria chamomilla L., Asteraceae)

Chamomile (Matricaria chamomilla L., Asteraceae) is one of the most important medicinal plants with antiphlogistic, spasmolytic, carminative, antibacterial and antimycotic properties. Thirty-one chloroplast markers were developed, optimised for high-resolution melting analysis. Subsequently, 23 M. chamomilla accessions (247 individuals) complemented with 2 individuals of the closely related species M. discoidea were analysed with this marker set. The marker set can practically be reduced to 20 markers without information loss due to the linkage of 16 markers. In total, 20 chlorotypes (multilocus genotypes) were identified, organised in three evolutionary main lineages. Only 8 accessions were monomorphic, the other 15 accessions had between 2 and 6 chlorotypes per accession. The high number of polymorphic accessions and the high number of chlorotypes within many accessions indicate already a high degree of variability within accessions, confirmed by the 66% variation within by AMOVA. Gene diversity of the polymorphic accessions ranged between 0.069 and 0.261. Since many cultivars had their origin in wild populations of the countries where breeding took place, a first hypothetical indication of the geographic origin of chamomile could point to Albania and adjacent countries. The ‘ancient chlorotype’ was identified by comparing published plastome sequences of Artemisia annua and Lactuca sativa. The ‘ancient chlorotype’ was present only in the closely related M. discoidea but not in any of the M. chamomilla accessions. Two commercially important tetraploid cultivars proofed to be unrelated to their presumed diploid parents.

Effects of sediment and water column acidification on growth, survival, burrowing behaviour, and GABAA receptor function of benthic invertebrates

In coastal regions, sediment-dwelling animals are exposed to a high degree of variability in seawater and sediment pH and pH is expected to decline due to anthropogenic effects. The impacts of 6-week exposure to reduced-pH seawater on length, weight, and survival of two species of molluscs that inhabit mudflats, juvenile soft-shell clams (Mya arenaria) and adult mud snails (Tritia obsoleta), were examined in two laboratory trials (2017 and 2018). The interactive effects of this prior exposure to water column acidification and subsequent sediment acidification on burrowing behaviour were then investigated for these mollusc species and adults of the amphipod Corophium volutator. In a separate experiment, the potential involvement of GABAA receptors in changes in burrowing behaviour in reduced-pH conditions was tested by exposing three species: C. volutator, T. obsoleta, and the Baltic clam Limecola balthica to sediment acidification and the neuroinhibitor gabazine. Reduced-pH water conditions only decreased the shell length of T. obsoleta in 2017 while all other morphometric metrics were not significantly impacted for this species in either year or for M. arenaria. The burrowing of T. obsoleta was reduced by 13% in acidified sediments in one of the two years but not by prior exposure to water column acidification. The burrowing of M. arenaria was not affected by either factor. The burrowing of C. volutator was impacted by the interaction of water column exposure and sediment acidification in 2017 with the acidified water, control sediment treatment having 14% higher burrowing then the remaining treatment combinations. In 2018, C. volutator burrowing was reduced in acidified sediment by 30%. The presence of gabazine only had an interactive effect on the burrowing of one species, C. volutator. The presence of gabazine increased the proportion of C. volutator individuals burrowed in the acidified water treatment by almost 30%, suggesting that GABAA neuroreceptors are involved in the mechanism for the impact of sediment acidification on burrowing in this species. The results of our experiments indicate that there is taxonomic variation in species' responses of benthic invertebrates to ocean and sediment acidification with respect to growth, survival, and burrowing behaviour.

Characterization of an Emerging Enterococcus cecorum Outbreak Causing Severe Systemic Disease with Concurrent Leg Problems in a Broiler Integrator in the Southern United States.

Enterococcus cecorum has been associated mainly with osteomyelitis of the free thoracic vertebra in chickens. However, there are reports of E. cecorum producing septicemic lesions and having tropism for cartilages, resulting in the presentation of femoral head necrosis and synovitis. This paper discusses the presentation of E. cecorum as it relates to an outbreak in one vertical integrator where the main lesions were related to septicemia. Using a convenience sampling method, 100 broiler chicken cases received at the Poultry Research and Diagnostic Laboratory of Mississippi State University from April to December of 2021 were analyzed. The peak in cases was observed from June to August. The average age of broilers was 21 days with a range of 15-31 days. Most of these cases were related to systemic disease and leg problems, with gross lesions including characteristic pericarditis along with perihepatitis, osteomyelitis, and arthritis. In six of the 100 cases, E cecorum was isolated from the free thoracic vertebra, with the remaining being recovered from various other locations including liver, pericardium, hock/joint, femoral head, and bone marrow. Enterococcus cecorum identification was performed by using Vitek matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. These results were then sent to the research-use only SARAMIS database for analysis. Once the spectra of the isolates were imported, the relative and absolute taxonomy were analyzed. Two super spectrums and three clusters by homology were identified. The minimal inhibitory concentrations obtained by antimicrobial sensitivity tests were analyzed using WHONET Microbiology Laboratory Database Software. No isolates were pan-susceptible, 80% of isolates were noted to be resistant to ≥3 classes of antibiotics and, in general, isolates exhibited a high degree of variability when examining antimicrobial resistance patterns.

Feasibility of Tea/Tree Intercropping Plantations on Soil Ecological Service Function in China

In order to explore whether tea/tree intercropping plantations have positive effects on soil ecosystem services functions, the possible effects of intercropping cultivation of 151 different tea and other species’ intercropping setups were summarized and analyzed in terms of three aspects of soil ecological service functions (supply services, support services, and regulating services). An ArcGIS map was plotted to show the distribution of existing intercropping plantations in China up to June 2021. Furthermore, it was concluded that the benefits of intercropping tea plantations exceeded those of monocropping tea plantations in terms of soil ecosystem service functions, such as water retention capacity, mineral contents, effects on energy transformation, and regulating environmental conditions. Intercropping tea plantations were more sustainable than regular tea plantations because of the different degrees of variability and benefits in all three aspects mentioned above. However, tea and tree intercropping plantations often require careful planning and preliminary experimentation to determine the type of intercropping that will have positive impacts, especially in the long term.

Section et/ou résection verticale des alaires en rhinoplastie

Nasal tip plasty is a real functional and aesthetical challenge in rhinoplasty. Many techniques have been described with different degrees of variability. The classic technique is the vertical division of the domes with section of the intermediate domes and directed healing without suture or cartilaginous grafting. The technique is based on an alar section or resection combined with a transdomal suture (STD) which allows control of the projection and rotation of the nasal tip.

Identifying Neural Signatures of Dopamine Signaling with Machine Learning.

The emergence of new tools to image neurotransmitters, neuromodulators, and neuropeptides has transformed our understanding of the role of neurochemistry in brain development and cognition, yet analysis of this new dimension of neurobiological information remains challenging. Here, we image dopamine modulation in striatal brain tissue slices with near-infrared catecholamine nanosensors (nIRCat) and implement machine learning to determine which features of dopamine modulation are unique to changes in stimulation strength, and to different neuroanatomical regions. We trained a support vector machine and a random forest classifier to decide whether the recordings were made from the dorsolateral striatum (DLS) versus the dorsomedial striatum (DMS) and find that machine learning is able to accurately distinguish dopamine release that occurs in DLS from that occurring in DMS in a manner unachievable with canonical statistical analysis. Furthermore, our analysis determines that dopamine modulatory signals including the number of unique dopamine release sites and peak dopamine released per stimulation event are most predictive of neuroanatomy. This is in light of integrated neuromodulator amount being the conventional metric used to monitor neuromodulation in animal studies. Lastly, our study finds that machine learning discrimination of different stimulation strengths or neuroanatomical regions is only possible in adult animals, suggesting a high degree of variability in dopamine modulatory kinetics during animal development. Our study highlights that machine learning could become a broadly utilized tool to differentiate between neuroanatomical regions or between neurotypical and disease states, with features not detectable by conventional statistical analysis.

Cortical responses correlate with speech performance in pre-lingually deaf cochlear implant children.

Cochlear implantation is currently the most successful intervention for severe-to-profound sensorineural hearing loss, particularly in deaf infants and children. Nonetheless, there remains a significant degree of variability in the outcomes of CI post-implantation. The purpose of this study was to understand the cortical correlates of the variability in speech outcomes with a cochlear implant in pre-lingually deaf children using functional near-infrared spectroscopy (fNIRS), an emerging brain-imaging technique. In this experiment, cortical activities when processing visual speech and two levels of auditory speech, including auditory speech in quiet and in noise with signal-to-noise ratios of 10 dB, were examined in 38 CI recipients with pre-lingual deafness and 36 normally hearing children whose age and sex matched CI users. The HOPE corpus (a corpus of Mandarin sentences) was used to generate speech stimuli. The regions of interest (ROIs) for the fNIRS measurements were fronto-temporal-parietal networks involved in language processing, including bilateral superior temporal gyrus, left inferior frontal gyrus, and bilateral inferior parietal lobes. The fNIRS results confirmed and extended findings previously reported in the neuroimaging literature. Firstly, cortical responses of superior temporal gyrus to both auditory and visual speech in CI users were directly correlated to auditory speech perception scores, with the strongest positive association between the levels of cross-modal reorganization and CI outcome. Secondly, compared to NH controls, CI users, particularly those with good speech perception, showed larger cortical activation in the left inferior frontal gyrus in response to all speech stimuli used in the experiment. In conclusion, cross-modal activation to visual speech in the auditory cortex of pre-lingually deaf CI children may be at least one of the neural bases of highly variable CI performance due to its beneficial effects for speech understanding, thus supporting the prediction and assessment of CI outcomes in clinic. Additionally, cortical activation of the left inferior frontal gyrus may be a cortical marker for effortful listening.

A closer look at the sources of variability in scalar implicature derivation: a review

For more than 20 years, studies in experimental pragmatics have provided invaluable insights into the cognitive processes involved in deriving scalar implicatures and achieving inferential comprehension. However, the reports have always contained a notable degree of variability that remained inadequately discussed in the literature. For instance, upon closer inspection of the experimental record, one can always find a group of individuals who tend to be largely pragmatic, overwhelmingly logical, or sometimes mixed not showing a clear preference. There also exist newly-devised paradigms that prompt a radically different type of response than other paradigms, and thus new evidence casting doubt on long-established findings in the field. More recent research on scalar diversity further suggests that differences in the semantic structure of scalar words can lead to differing rates of scalar implicatures and can modulate the time invested in pragmatic processing. Indeed, one can contend that the current empirical landscape on scalar implicatures can be characterized as having three primary sources of variability: inter-individual, methodological, and linguistic. What factor or factors are behind these patterns of variability, and how can we interpret them in light of a pragmatic theory? This paper has a 2-fold objective: one is to review the previous experimental record on scalar implicatures from variability-based lenses, and the other to discuss the factor(s) that could account for this observed variability in the literature. Avenues for future research are provided.

XMM-Newton observation of V1504 Cyg as a probe for the existence of an evaporated corona

Aims. We present an analysis of an XMM-Newton observation of the dwarf nova V1504 Cyg during the decline from an outburst. Our goal is to search for evidence of an evaporated X-ray corona. Such a corona can be understood as an optically thin and geometrically thick disc around the central part of an optically thick and geometrically thin disc. Methods. We study the X-ray spectra of a dwarf nova using a cooling-flow model and the evolution in the amplitude of variability and power density spectra in the UV and X-ray. Results. The X-ray (pn) count rate increases from initially around 0.03 cps to 0.17 cps, with a harder spectrum and a higher degree of variability. Meanwhile, the OM/UVW1 light curve follows a slow decline with a decreasing amplitude of variability. Next, we split the X-ray data into two segments and analysed them separately. Both were described by a cooling-flow model, while the first low-luminosity segment required an additional power-law component, suggesting the presence of a wind. A spectral fitting revealed a higher temperature for the second brighter segment. A timing analysis revealed a potential break frequency at log(f/Hz) = −3.02 during the decline towards the quiescence. This detection is in agreement with optical data from Kepler observations. Conclusions. The X-ray nature of the break frequency supports the innermost parts of the disc as source of the variability. Moreover, a similar frequency was observed in several other cataclysmic variables. Thus, a sandwich model where a geometrically thick corona surrounds the geometrically thin disc is a plausible accretion configuration.

An Unsaturated Hydraulic Conductivity Model Based on the Capillary Bundle Model, the Brooks‐Corey Model and Waxman‐Smits Model

AbstractSoil unsaturated hydraulic conductivity (K), which depends on water content (θ) and matric potential (ψ), exhibits a high degree of variability at the field scale. Here we first develop a theoretical hydraulic‐electrical conductivity (σ) relationship under low and high salinity cases based on the capillary bundle model and Waxman and Smits model which can account for the non‐linear behavior of σ at low salinities. Then the K‐σ relationship is converted into a K(θ, ψ) model using the Brooks‐Corey model. The model includes two parameters c and γ. Parameter c accounts for the variation of the term (λ + 2)/(λ + 4) where λ is the pore size distribution parameter in the Brooks‐Corey model, and the term m‐n where m and n are Archie's saturation and cementation exponents, respectively. Parameter γ is the sum of the tortuosity factor accounting for the differences between hydraulic and electrical tortuosity and Archie's saturation exponent. Based on a calibration data set of 150 soils selected from the UNSODA database, the best fitting log(c) and γ values were determined as −2.53 and 1.92, −4.39 and −0.14, −5.01 and −1.34, and −5.79 and −2.27 for four textural groups. The estimated log10(K) values with the new K(θ, ψ) model compared well to the measured values from an independent data set of 49 soils selected from the UNSODA database, with mean error (ME), relative error (RE), root mean square error (RMSE) and coefficient of determination (R2) values of 0.02, 8.8%, 0.80 and 0.73, respectively. A second test of the new K(θ, ψ) model using a data set representing 23 soils reported in the literature also showed good agreement between estimated and measured log10(K) values with ME of −0.01, RE of 9.5%, RMSE of 0.77 and R2 of 0.85. The new K(θ, ψ) model outperformed the Mualem‐van Genuchten model and two recently published pedo‐transfer functions. The new K(θ, ψ) model can be applied for estimating K under field conditions and for hydrologic modeling without need for soil water retention curve data fitting to derive a K function.

Testing Okun's Law Over the Business Cycle: The Case of South Africa

ABSTRACT: Understanding the relationship between output and unemployment (Okun's law) is important for policymakers, particularly during crises. One of the aspects of Okun's law that is commonly examined during crises is the structural stability and behavior of Okun's law over the business cycle. While this issue has been addressed empirically in developed countries, little is known about it in developing countries such as South Africa. Hence, this study examines the structural stability and behavior of Okun's law over the business cycle in South Africa. This study adopts both the difference and gap methods of formalizing Okun's law to implement its objectives. The recursive rolling window method was used to test the structural stability of Okun's law over time. The behavior of Okun's law over the business cycle is examined using the Markov-switching regression method. This study was conducted using the data from 1994Q1 to 2021Q1. The results of this study show that Okun's law varies over the business cycle because the response of unemployment to economic expansion is quite different from that of economic contraction. Okun's law holds during economic expansion but fails to hold during an economic recession. Evidence from this study also reveals that the coefficients of Okun's law vary over time. For instance, in the case of the difference method, Okun's coefficients range from 0.063 to 1.221 in absolute terms. For the gap method, especially when the H-P filtering method is applied, Okun's coefficients range from 0.509 to 9.412 in absolute terms. In summary, the findings from this study suggest that cyclical unemployment responds more significantly to cyclical output growth than the response of changes in unemployment to changes in output. In addition, this study proves that Okun's law is unstable over time in South Africa. These findings imply a high degree of variability between the labor and goods markets in the country. Hence, policies must be designed to harmonize the divergence between the two markets. This will require the implementation of macroeconomic policies such as fiscal and monetary policies. From a fiscal policy perspective, the government should reduce taxes or provide tax holidays to firms. The interest rate should be set low in the case of monetary policy.

PCR-RFLP Analysis of Insulin-Like Growth Factor 2 Gene Polymorphisms in Two Commercial Broiler Chicken Strains (Cobb 500 and Hubbard F-15) and Their Associations with Performance Traits.

The present research aimed to study the polymorphisms of the chicken insulin-like growth factor 2 (IGF2) in two commercial broiler breeds (Cobb 500 and Hubbard F-15). In total, 300 avian blood samples were obtained. The genomic DNA was isolated using a fast salt-extraction technique. Moreover, polymerase chain reaction (PCR) was used to amplify 1146 bp fragments of the gene. The amplified fragments were subjected to restriction enzyme digestion using the HinfI endonuclease enzyme, and the digested products were separated on a 2% agarose gel. The findings indicated that there were two alleles T and C for the target locus, with frequencies of 73.3% and 26.7%, respectively. Three distinct genotype variations, TT, TC, and CC, were found, with genotype frequencies of 59.1%, 28.4%, and 12.5%, respectively. A test based on actual and anticipated frequencies of various genotypic variances of the IGF2 gene revealed that the divergence from Hardy-Weinberg equilibrium was not significant (P≤0.01) in commercial broiler breeds (Cobb 500 and Hubbard F-15) chickens. In addition, it was found that birds with genotype TC had a greater body mass at 8 weeks of age, compared to those with genotypes TT and CC. It was determined that the IGF2 gene exhibited a significant degree of variability and might be regarded as a possible genetic marker in selection and breeding programs for poultry.