Van Zyl Research Articles

Using Positive Psychology to Uplift Minority Youth: The Importance of Sound Conceptualization and Contextualization

As addressed in the critiques related to theory, measurement, and contextualization identified in Van Zyl et al.’s (J Posit Psychol 1–30, 2023) systematic review, positive psychology has failed to robustly conceptualize and assess the contextually nuanced character and virtue development of non-WEIRD samples, particularly ethnic-racial and religious minority youth, such as Muslim American adolescents. The purpose of this commentary was to provide a conceptually sound and contextualized approach to studying virtue development that uplifts minority youth’s lived experiences and does not undermine their development. We presented potential solutions for criticisms of positive psychology related to theoretical underpinnings, measurement, and decontextualized approach and illustrated the utility of these solutions with concrete examples within the context of Muslim American adolescents as an example of a non-WEIRD population. The paper concluded with recommendations for how these strategies could be similarly applied to uplift other ethnic-racial and religious minority youth populations.

Weak Target Detection Based on Full-Polarization Scattering Features under Sea Clutter Background

Aiming at the low observable target detection under sea clutter backgrounds, this paper emphasizes the exploration of distinguishable full-polarization features between target and sea clutter echoes. To overcome the shortcomings of the existing polarization feature-based methods, the full-polarization features of sea clutter are modeled and analyzed in detail by using Van Zyl polarization decomposition. Then, three polarimetric features (the relative surface scattering energy, the relative dihedral scattering energy and the relative diffuse scattering energy) are extracted from the fully polarimetric radar sea clutter echoes, which improve the feature differences between sea clutter and targets. And a tri-polarimetric feature detector with constant false alarm rate (CFAR) is constructed based on the fast convex hull learning algorithm. The experimental results on the real measured IPIX radar datasets prove that the proposed full-polarization feature detector obtains more competitive detection performance and lower computational complexity than the several existing feature-based detectors.

A bioarchaeological analysis of skeletal remains from Van Zyl’s farm, Clarens, Free State, South Africa

In 1933, several skeletons were recovered from Van Zyl’s farm near Clarens in the Free State Province of South Africa. Apart from the general location from which these remains were recovered, very little was known about these individuals’ temporal and cultural contexts. This study aimed to analyse and describe these skeletons and any possible associated historical and archaeological records to reconstruct aspects of their archaeological context and lifestyle. Most of the remains were commingled, and from these, a minimum number of individuals (MNI) of 11 was established. There was one complete and intact individual, which raised the sample size to 12 individuals. The assemblage comprised three juveniles (<5 years) and nine adults (between the ages of 20 and 45, and 50+ years), of which six were estimated to be males and three females. The complete individual, an older adult male, was radiocarbon dated to 844±35 BP (Ua-61831). Several individuals had osteoarthritis and signs of non-specific and dental disease. One of the younger adult female individuals had culturally modified upper central incisors. Stable δ13C and δ15N values indicated a predominantly C4 terrestrial plant-based diet, with little reliance on animal-derived protein. The only complete male individual was of interest due to his unique biological characteristics, being very tall and morphologically robust and clearly not of Khoe-San ancestry. The date obtained for the complete individual is unusual as it is generally thought that Bantu-speaking farmers only reached the interior Drakensberg and Maluti regions much later.

Regspraak: Onderhoudskostes vir koekoekskuikens – wie moet vir die gelag betaal, of rus die skade maar waar dit val?

Regspraak: Onderhoudskostes vir koekoekskuikens – wie moet vir die gelag betaal, of rus die skade maar waar dit val?

CORONARY ARTERY DISEASE AND DEPRESSION: A MISSING PILLAR IN MANAGEMENT

Patients with coronary artery disease have multiple co-morbids that include dyslipidemia, hypertension, diabetes mellitus, smoking and physical inactivity. It has been seen that depression is another issue in these patients that need close attention. Studies have shown that it affects between 20% and 40% in patients with coronary artery disease (CAD) and have a higher prevalence than in general population.1 One of the study done by SS Bokhari et al.2 has shown a point prevalence of depression in CAD as 37% (31.3% males and 53.8% females).
 Numerous studies have shown that patients with CAD and depression have poor health outcomes.3 Depression in different aspects in Pakistani population after myocardial infarction,4 after PCI5 and in in-hospital patients with CAD6 were evaluated and found to have significant mental illness which co-relates with the results of other international studies.
 Keeping all the research studies American Heart Association wrote a scientific statement and endorsed depression as a risk factor for cardiac morbidity and mortality.7 Importance of depression screening as a part of myocardial infarction protocol for caring patients with Ischemic Heart Disease was seen in TRIUMPH trial (Translational Research Investigating Underlying Disparities in Acute Myocordial Infarction Patients Health Status)8 ENRICHD Trial (Enhancing Recovery in Coronary Heart Disease)9 use of citalopram or serlatine plus as clinical management was used for depressive symptoms with CAD in CREATE Trial (Canadian Cardiac Randomized Evaluation of Antidepressant and Psychotherapy Efficacy).10
 In Pakistan where prevalent of CAD is high i.e. one in 4 middle age adults,11 managing such patients are numerous that includes revascularization (Surgical and Interventional), drugs and treatment of modifiable and nonmodifiable risk factors. Despite all these efforts it’s a need of time to focus on diagnosing depression in CAD to improve outcomes. Depression screening should be conducted to identify these important risk factors and treated with drugs in reducing morbidity and mortality.
 References
 
 Lett HS, Blumenthal JA, Babyak MA, Sherwood A, Strauman T, Robins C, et al. Depression as a risk factor for coronary artery disease: evidence, mechanisms, and treatment. Psychosom Med. 2004;66:305-15.
 Bokhari SS, Samad AH, Hanif S, Hadique S, Cheema MQ, Fazal MAS, et al. Prevalence of depression in patients with coronary artery disease in a tertiary care hospital in Pakistan. J Pak Med Assoc. 2002;52(9):436-9.
 Jackson CA, Sudlow CLM, Mishra GD. Psychological Distress and Risk of Myocardial Infarction and Stroke in the 45 and Up Study. Circ Cardiovasc Qual Outcomes. 2018;11:e004500.
 Saeed H, Khan F, Mohsin SF, Qizilbash FH, Fraz TR, Jawed Q, et al. Pattern of Depression Among Patients of Myocardial Infarction in Karachi, Pakistan: A Cross-sectional Study. Cureus. 2018;10(8):e3199
 Mujtaba SF, Sial JA, Karim M. Depression and Anxiety in patients undergoing Percutaneous Coronary Intervention for Acute Coronary Syndrome. Pak J Med Sci. 2020;36(5):1100-5.
 Khan SA, Azhar S, Asad SM, Iqbal A, Kousar R, Ahmad M, et al. Assessment of anxiety and depression in hospitalized cardiac patients of Faisalabad Institute of Cardiology, Pakistan. Trop J Pharm Res. 2016;15(11):2483-7
 Lichtman JH, Froelicher ES, Blumenthal JA, Carney RM, Doering LV, Frasure-Smith N, et al. Depression as a risk factor for poor prognosis among patients with acute coronary syndrome: systematic review and recommendations: a scientific statement from the American Heart Association. Circulation 2014;129:1350-69.
 Smolderen KG, Buchanan DM, Gosch K, Whooley M, Chan PS, Vaccarino V, et al. Depression Treatment and 1-Year Mortality Following Acute Myocardial Infarction: Insights from the TRIUMPH Registry. Circulation 2017;135:1681-9.
 Berkman LF, Blumenthal J, Burg M, Carney RM, Catellier D, Cowan MJ, et al. Effects of treating depression and low perceived social support on clinical events after myocardial infarction: the Enhancing Recovery in Coronary Heart Disease Patients (ENRICHD) Randomized Trial. JAMA 2003;289:3106-16.
 Lespérance F, Frasure-Smith N, Koszycki D, Laliberté MA, van Zyl LT, Baker B, et al. Effects of citalopram and interpersonal psychotherapy on depression in patients with coronary artery disease: the Canadian Cardiac Randomized Evaluation of Antidepressant and Psychotherapy Efficacy (CREATE) trial. JAMA 2007;297:367-79.
 Jafar TH, Jafary FH, Jessani S, Chaturvedi N. Heart disease epidemic in Pakistan: women and men at equal risk. Am Heart J. 2005;150(2):221-6.

PARATE EXECUTIE AND PUBLIC POLICY. THE SUPREME COURT OF APPEAL PROVIDES FURTHER GUIDELINES

The right of a creditor to realise the property of its debtor without first obtaining the permission of the court is clouded in controversy. This type of extra-judicial execution is known in Roman-Dutch law as parate executie (literally: “immediate execution”). The essence of parate executie is that it allows the creditor to self-help in the event of default by the debtor. The tenability of parate executie has come under judicial scrutiny in the recent past, not least because of its potential infringement of the provisions contained in section 34 of the Constitution of the Republic of South Africa, 1996. Section 34 provides that “[e]veryone has the right to have any dispute that can be resolved by the application of law decided in a fair public hearing before a court or, where appropriate, another independent and impartial tribunal or forum” (see in this regard, First National Bank of South Africa Ltd v Land and Agricultural Bank of South Africa; Sheard v Land and Agricultural Bank of South Africa 2000 3 SA 626 (CC); (2000 8 BCLR 876); Chief Lesapo v North West Agricultural Bank 2001 1 SA 409 (CC); Findevco (Pty) Ltd v Faceformat SA (Pty) Ltd 2001 1 SA 251 (E); De Beer v Keyser 2002 1 SA 827 (SCA); Senwes Ltd v Muller 2002 4 SA 134 (T); Shoprite Checkers (Pty) Ltd t/a OK Franchise Division v Juglal NO (unreported case no 6049/01, 13 Sep 2002 (D)) (which was endorsed on appeal in Juglal NO and another v Shoprite Checkers (Pty) Ltd t/a OK Franchise Division 2004 5 SA 248 (SCA)); Graf v Buechel 2003 4 SA 378 (SCA) (which dealt with a forfeiture clause (ie, pactum commissorium) and therefore falls outside the direct scope of the present note); and Bock v Dubororo Investments (Pty) Ltd 2004 2 SA 242 (SCA)).These cases have further been discussed in a number of case notes (see Scott “Summary Execution Clauses in Pledge and Perfecting Clauses in Notarial Bonds” 2002 65 THRHR 656 et seq; Steyn “Perfection Clauses, Summary Execution (Parate Executie) Clauses, Forfeiture Clauses (Pacta Commissoria) and Conditional Sales in Pledge Agreements and Notarial Bonds – The Position Clarified” 2004 Obiter 443 et seq; and Schulze “Parate Executie, Pacta Commissoria, Banks and Mortgage Bonds” 2004 37 De Jure 256 et seq).Although parate executie is employed by many creditors to realise the security that they hold, commercial banks, being the prime example of money lenders in modern times, have a particular vested interest in retaining parate executie as a valid instrument to realise movables that were given to the bank as security.In the recently reported decision in SA Bank of Athens Ltd v Van Zyl (2005 5 SA 93 (SCA)) the court was asked to pronounce on the validity of a clause that provides for parate executie on the movable property (in the present case: four investment policies) of a defaulting debtor which were held by a bank. The court was further asked to determine whether a parate executie clause is in conflict with public policy.

Calibration and Validation of Polarimetric ALOS2-PALSAR2

PALSAR2 polarimetric distortion matrix is measured using corner reflectors deployed in the Amazonian forest. The Amazonian forest near the geomagnetic equator provides ideal sites for the assessment of L-band PALSAR2 antenna parameters, at free Faraday rotation. Corner reflectors (CRs) deployed at free Faraday rotation provide accurate estimation of antenna cross-talks in contrast to the biased measurements obtained with CRs deployed at significant Faraday rotation. The extended Freeman–Van Zyl calibration method introduced and validated for ALOS-PALSAR calibration is used for the assessment of PALSAR-2 calibration parameters. Six datasets collected over the Amazonian rainforests (with CRs) are used to assess PALSAR-2 distortion matrix for five beams (FP6-3 to FP6-7) with incidence angle varying from 25° to 40°. It is shown that the PALSAR2 antenna is highly isolated with very low cross-talks (lower than −40 dB). Finally, the impact of a significant Faraday rotation on antenna cross-talk measurements using CR is discussed.

An insight into the sensitivity of fully polarimetric SAR data to biomass of pearl millet crop

The development of polarimetric decomposition techniques improves the capability to understand the complex scattering mechanisms occurring in the dryland crops. The present study is focused on assessing the sensitivity of coherent, incoherent, model and Eigen vector-based decomposition techniques from multitemporal Radarsat-2 polarimetric dataset to scattering mechanisms occurring in the critical growth stages of pearl millet crop. Yamaguchi volume component along with its temporal response was observed to be sensitive and reliable due to its dynamic biomass characterization. Overestimation of volume component and earlier saturation of biomass from 4 kgm−2 were observed limitations in Freeman 2 & 3 component decomposition when dealing with higher vegetation crops. The decrease in volume scattering over increasing biomass proved Van Zyl response contrary to the established understanding. Panicle stage was identified as the critical stage for discriminating pearl millet from similar structured maize and sorghum crops. In this stage, alpha angle generated from Cloude-Pottier decomposition almost reached 550 indicating the increase in contribution of dihedral scattering due to vertical prominent panicles in the pearl millet fields. The various Touzi parameters (α1, Ψ1, φ1 and τ1) were observed to have sensitivity towards changes in crop canopy structures, which will require further research to verify. The proposed Δ(F3-Y4) was the most suitable Volume Difference Index (VDI) for characterizing biomass of erectophile crops as the dynamic biomass response was found even beyond 8 kgm−2.

Statistical Comparison of Melting Iceberg Backscatter Embedded in Sea Ice and Open Water Using RADARSAT-2 Images of the Newfoundland Sea

This article investigates and compares polarimetric signatures of icebergs embedded in sea ice and icebergs in open water. The main objective is to study on the backscatter properties of melting iceberg and to check on whether there is any distinguishable property in them in the case of different background clutter conditions (i.e. sea ice and open water). This study results will improve the potential of iceberg detection using radar polarimetry. RADARSAT-2 images have been used for the analysis acquired over locations near the coastline (approximately 3–35 km) of the island of Newfoundland. For analysis, polarimetry parameters, such as co-(HH) and cross-(HV) polarization and several popular decomposition techniques, specifically Pauli, Freeman–Durden, Yamaguchi, Cloud–Pottier, and van Zyl, have been used to determine the polarimetric signatures of icebergs and sea ice. The statistical hypothesis T-test has been applied to achieve a precise comparison among backscatters from different icebergs groups. Statistical results tend to show a dominant surface scattering mechanism for icebergs in all types of clutter conditions. Moreover, icebergs in open water produce larger volume scatter than icebergs in sea ice, whereas icebergs in sea ice produce larger surface scatter than icebergs in open water.

THE COURT REFUSES TO GRANT A CERTIFICATION ORDER IN THE BREADCARTEL CLASS ACTION CASES: A CLOSER EXAMINATION OF THE WESTERN CAPE JUDGMENT The Trustees for the time being of the Children’s Resource Centre Trust v Pioneer Foods (Pty) and Imraahn Ismail Muka

In the above cases, which came before the Western Cape High Court for hearing on both 23 and 25 November 2010, the judge, Francois Van Zyl, AJ dismissed the two applications for leave to institute the class actions on behalf of the applicants against the respondent bread-manufacturing companies (ie, Pioneer Foods (Pty) Ltd, Tiger Consumer Brands Limited and Premier Foods Limited)who, together with Foodcorp (Pty) Ltd, enjoy between 50% and 60% of the domestic bread market in South Africa. The judge promised to give reasons for his decision subsequent to his ruling on 26 November 2010 and, indeed, on 07 April 2011, he provided detailed reasons for his decision in terms of Rule 49(1)(c) of the Rules of the High Court. Material facts as accepted by the Court and which are relevant for the purposes of this case note are as follows: Both cases emanated from a complaint raised with the Competition Commission following an allegation of a bread cartel operated by the Respondent companies in the Western Cape in December 2006. After a preliminary investigation, the Commission initiated a complaint against the three respondents in the above applications. One of the respondent companies, Premier, applied for leniency and disclosed to the Commission that, together with Pioneer and Tiger, it was part of a bread cartel in the Western Cape which fixed the selling price of bread and other trading conditions. Following this disclosure, Premier was granted corporate leniency by the Commission and, on 14 February 2007, an agreement was concluded between Premier and the Commission in terms of which Premier agreed to assist the Commission in its investigations and subsequent prosecution of the other respondents before the competition Tribunal. On the same day that the corporate-leniency agreement was concluded with Premier, the Commission referred the complaint made against Tiger and Pioneer in the Western Cape to the Competition Tribunal. Following the referral, Tiger negotiated a consent agreement with the Commission, in terms of which it admitted that it enteredinto an agreement with Premier and Pioneer during December 2006 regarding bread prices and discounts to independent distributors in the Western Cape which amounted to a contravention of the provisions of the Competition Act (89 of 1998). On 27 November 2007, the Competition Tribunal made a consent order against Tiger in terms of section 49D of the Competition Act and levied against it an agreed administrative penalty of approximately R98 million. With regard to the third respondent company, Pioneer, complaints against it were subsequently heard by the Competition Tribunal and, on 03 February 2010, it was found that, together with Premier and Tiger, it was part of a bread cartel in December 2006 in the Western Cape in contravention of the provisions of the Competition Act. Taking into account other contraventions of the Competition Act committed by the company in other parts of the country, Pioneer wassubsequently ordered to pay an administrative penalty of approximately R195 million. In the final analysis, the facts established that bread-cartel operations took place during December 2006 in the Western Cape. It was further established that the three respondent companies were part of that bread cartel in contravention of the provisions of the Competition Act (ie, Premier applied forand was granted corporate leniency, Tiger negotiated a consent agreement which was made a consent order by the Competition Tribunal in terms of the Competition Act and Pioneer was found by the Tribunal to have been in contravention of the Competition Act and an administrative penalty was imposed upon it). It was in the context of the above circumstances that the applicants brought applications for class-action certification against the three respondents in the Western Cape High Court for the compensation of theconsumers and distributors who were detrimentally affected by the conduct of the respondent companies in contravention of the Competition Act. The AJ’s primary reasons for dismissing the applications included, firstly, the fact that while it is important in cases such as this to clearly identify a class for the purposes of the “class action” on the “opt-out” basis, the applicants failed to identify the “class” for the purposes of the application.

Assessment of surface soil moisture from ALOS PALSAR-2 in small-scale maize fields using polarimetric decomposition technique

Surface soil moisture knowledge is important, especially in agriculture and irrigation management. Properties of microwave remote sensing like penetration power and longer wavelength facilitate retrieval of surface soil moisture. ALOS PALSAR-2, quad polarized data are used to retrieve surface soil moisture using polarization decomposition techniques in a marginal farmer small-scale maize field. The focus of the study is to explore the utility of ALOS PALSAR-2 in retrieving surface soil moisture using the polarization decomposition technique. The demonstration of the study is carried out in Malavalli village, southern India, an agricultural predominant area. The study involves field soil moisture sampling in synchronous with satellite pass, measuring soil properties, preprocessing of SAR data, polarization decomposition, proportional analysis, regression analysis, model calibration and validation. Van Zyl decomposition gave the highest surface scattering component (43%) and reduced volumetric scattering component compared to Yamaguchi and Freeman–Durden decomposition. Surface scattering component of Yamaguchi decomposition gave a good coefficient of determination (R2 = 0.8029) with field-measured surface soil moisture. The semi-empirical model (SEM) was developed using surface scattering component and depolarization ratio with adjusted R2 = 0.75 at 95% confidence interval. On its comparison with existing soil moisture models, it is observed that the developed model is performing well with RMSE and AEmax of 1.81 and 2.88, respectively. Implying the applicability of ALOS PALSAR-2 in soil moisture retrieval in marginal farmer small-scale maize fields gave satisfactory results of accuracy.

Decomposition-Based Soil Moisture Estimation Using UAVSAR Fully Polarimetric Images

Polarimetric decomposition extracts scattering features that are indicative of the physical characteristics of the target. In this study, three polarimetric decomposition methods were tested for soil moisture estimation over agricultural fields using machine learning algorithms. Features extracted from model-based Freeman–Durden, Eigenvalue and Eigenvector based H/A/α, and Van Zyl decompositions were used as inputs in random forest and neural network regression algorithms. These algorithms were applied to retrieve soil moisture over soybean, wheat, and corn fields. A time series of polarimetric Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) data acquired during the Soil Moisture Active Passive Experiment 2012 (SMAPVEX12) field campaign was used for the training and validation of the algorithms. Three feature selection methods were tested to determine the best input features for the machine learning algorithms. The most accurate soil moisture estimates were derived from the random forest regression algorithm for soybeans, with a correlation of determination (R2) of 0.86, root mean square error (RMSE) of 0.041 m3 m−3 and mean absolute error (MAE) of 0.030 m3 m−3. Feature selection also impacted results. Some features like anisotropy, Horizontal transmit and Horizontal receive (HH), and surface roughness parameters (correlation length and RMS-H) had a direct effect on all algorithm performance enhancement as these parameters have a direct impact on the backscattered signal.

IT’S ABOUT TIME: Trying an Essay Film

This essay is about the essay, a form (as Adorno called it) of thought alive that is partial in the two senses of the word: subjective and fragmented. Thinking as social, performative, and always un-finished; as dialogic. Through the mythical figure of Cassandra, who could foresee the future but was cursed to be never believed, I tried to “figure,” make a figural shape for the thoughts on the indifference of people towards the imminent ecological disaster of the world. At the invitation of Jakub Mikurda of the Łódź Film School to come and make an essay film, within one week, but with the participation of many great professionals, I was able to create, at least in the first draft, the essay film IT’S ABOUT TIME!
 The ambiguity of the title suggests the bringing together of my thoughts about time, in relation to history in its interrelation with the present, and, as the exclamation mark intimates, the urgency to do something. The former is enacted by a tableau vivant of Cassandra’s lover Aeneas as Caravaggio’s John the Baptist, with a contemporary painting by David Reed shifting over it; and by interactions with two paintings by Ina van Zyl. The urgency is presented in many of the dialogues, quoted from various sources, especially Christa Wolf’s novel Cassandra. I argue that “thinking in film,” with film as a medium for thought, is what the essay film’s foremost vocation is. Through a reflection on “thought-images,” which I see as the result of “image-thinking,” I also argue for the intellectual gain to be had from “essaying” thought artistically.

NEW VEGETATION INDICES FOR FULL AND COMPACT POLARIMETRIC SAR DATA: IN PREPARATION FOR THE RADARSAT CONSTELLATION MISSION (RCM)

Abstract. In this paper, we present two radar vegetation indices for full-pol and compact-pol SAR data, respectively. Both are derived using the notion of a geodesic distance between observation and well-known scattering models available in the literature. While the full-pol version depends on a generalized volume scattering model, the compact-pol version uses the ideal depolariser to model the randomness in the vegetation. We have utilized the RADARSAT Constellation Mission (RCM) time-series data from the SAMPVEX16-MB campaign in the Manitoba region of Canada for comparing and assessing the indices in terms of the change in the biophysical parameters as well. The compact-pol data for comparison is simulated from the full-pol RCM time series. Both the indices show better performance at correlating with biophysical parameters such as Plant Area Index (PAI) and Volumetric Water Content (VWC) for wheat and soybean crops, in comparison to the state-of-art Radar Vegetation Index (RVI) of Kim and van Zyl. These indices are timely for the upcoming release of the data from the RCM, which will provide data in both full and compact-pol modes, aimed at better crop monitoring from space.

Discriminating Forest Successional Stages, Forest Degradation, and Land Use in Central Amazon Using ALOS/PALSAR-2 Full-Polarimetric Data

We discriminated different successional forest stages, forest degradation, and land use classes in the Tapajós National Forest (TNF), located in the Central Brazilian Amazon. We used full polarimetric images from ALOS/PALSAR-2 that have not yet been tested for land use and land cover (LULC) classification, neither for forest degradation classification in the TNF. Our specific objectives were: (1) to test the potential of ALOS/PALSAR-2 full polarimetric images to discriminate LULC classes and forest degradation; (2) to determine the optimum subset of attributes to be used in LULC classification and forest degradation studies; and (3) to evaluate the performance of Random Forest (RF) and Support Vector Machine (SVM) supervised classifications to discriminate LULC classes and forest degradation. PALSAR-2 images from 2015 and 2016 were processed to generate Radar Vegetation Index, Canopy Structure Index, Volume Scattering Index, Biomass Index, and Cloude–Pottier, van Zyl, Freeman–Durden, and Yamaguchi polarimetric decompositions. To determine the optimum subset, we used principal component analysis in order to select the best attributes to discriminate the LULC classes and forest degradation, which were classified by RF. Based on the variable importance score, we selected the four first attributes for 2015, alpha, anisotropy, volumetric scattering, and double-bounce, and for 2016, entropy, anisotropy, surface scattering, and biomass index, subsequently classified by SVM. Individual backscattering indexes and polarimetric decompositions were also considered in both RF and SVM classifiers. Yamaguchi decomposition performed by RF presented the best results, with an overall accuracy (OA) of 76.9% and 83.3%, and Kappa index of 0.70 and 0.80 for 2015 and 2016, respectively. The optimum subset classified by RF showed an OA of 75.4% and 79.9%, and Kappa index of 0.68 and 0.76 for 2015 and 2016, respectively. RF exhibited superior performance in relation to SVM in both years. Polarimetric attributes exhibited an adequate capability to discriminate forest degradation and classes of different ecological succession from the ones with less vegetation cover.

FROM THE EDITOR

Contributions to this issue all display a pragmatic orientation. H C van Rooy analyses Ezk. 29:1-26 in its exilic and post-exilic setting, to draw certain conclusions for the role of contemporary prophetic teaching. Jan Botha explains why rhetoric is so much in vogue, and what implications it might have for the practice of exegesis and for current New Testament scholarship. Cornel du Toit discusses basic concepts relating to ideology, and demonstrates how a constructive approach to ideology critique can be developed. Hermie van Zyl concludes with a basic overview of librarian theology and its main proponents.

Homeostatic Plasticity Shapes the Retinal Response to Photoreceptor Degeneration.

Homeostatic plasticity stabilizes input and activity levels during neural development, but whether it can restore connectivity and preserve circuit function during neurodegeneration is unknown. Photoreceptor degeneration is the most common cause of blindness in the industrialized world. Visual deficits are dominated by cone loss, which progresses slowly, leaving a window during which rewiring of second-order neurons (i.e., bipolar cells) could preserve function. Here we establish a transgenic model to induce cone degeneration with precise control and analyze bipolar cell responses and their effects on vision through anatomical reconstructions, invivo electrophysiology, and behavioral assays. In young retinas, we find that three bipolar cell types precisely restore input synapse numbers when 50% of cones degenerate but one does not. Of the three bipolar cell types that rewire, two contact new cones within stable dendritic territories, whereas one expands its dendrite arbors to reach new partners. In mature retinas, only one of four bipolar cell types rewires homeostatically. This steep decline in homeostatic plasticity is accompanied by reduced light responses of bipolar cells and deficits in visual behaviors. By contrast, light responses and behavioral performance are preserved when cones degenerate in young mice. Our results reveal unexpected cell type specificity and a steep maturational decline of homeostatic plasticity. The effect of homeostatic plasticity on functional outcomes identify it as a promising therapeutic target for retinal and other neurodegenerative diseases.

Book Review: Life imprisonment: A global human rights perspective by D. Van Zyl Smit and C. Appleton

Book Review: <i>Life imprisonment: A global human rights perspective</i> by D. Van Zyl Smit and C. Appleton

Spotlight in Plastic Surgery: January 2020

Spotlight in Plastic Surgery: January 2020

Soil Moisture Inversion Via Semiempirical and Machine Learning Methods With Full-Polarization Radarsat-2 and Polarimetric Target Decomposition Data: A Comparative Study

In this article, surface soil moisture was retrieved from Radarsat-2 and polarimetric target decomposition data by using semiempirical models and machine learning methods. The semiempirical models and machine learning techniques employed were Oh (1992), Dubois (1995), Oh (2004) and Generalized Regression Neural Network (GRNN), Least Squares - Support Vector Machine (LS-SVM), Extreme Learning Machine (ELM), Kernel based Extreme Learning Machine (KELM), Adaptive Network based Fuzzy Inference System (ANFIS), respectively. In addition, Yamaguchi, van Zyl, Freeman-Durden, H/A/α and Cloude polarimetric target decomposition methods were used in this study. For soil moisture inversion, firstly, preprocessing was applied to the Radarsat-2 image of two different dates with bare and moderately vegetated soil. Then, sigma nought coefficients and the polarimetric decomposition components were extracted as feature vector from preprocessed SAR image pixels corresponding to ground measured points. Lastly, sigma nought coefficients were used in semiempirical inversion models, and sigma nought coefficients and polarimetric decomposition components were used as input to machine learning methods. The best accuracy results for semiempirical models were 13.01 vol. % and 17.91 vol. % Root Mean Square Error (RMSE) for bare and moderately vegetated soil, respectively. The best accuracy for machine learning techniques were 4.04 vol. % and 2.72 vol. % RMSE for two dates, respectively. The results indicated that the machine learning techniques performed much better than the semiempirical models.