Persistent Shift Research Articles

Emerging forest–peatland bistability and resilience of European peatland carbon stores

Northern peatlands store large amounts of carbon. Observations indicate that forests and peatlands in northern biomes can be alternative stable states for a range of landscape settings. Climatic and hydrological changes may reduce the resilience of peatlands and forests, induce persistent shifts between these states, and release the carbon stored in peatlands. Here, we present a dynamic simulation model constrained and validated by a wide set of observations to quantify how feedbacks in water and carbon cycling control resilience of both peatlands and forests in northern landscapes. Our results show that 34% of Europe (area) has a climate that can currently sustain existing rainwater-fed peatlands (raised bogs). However, raised bog initiation and restoration by water conservation measures after the original peat soil has disappeared is only possible in 10% of Europe where the climate allows raised bogs to initiate and outcompete forests. Moreover, in another 10% of Europe, existing raised bogs (concerning ∼20% of the European raised bogs) are already affected by ongoing climate change. Here, forests may overgrow peatlands, which could potentially release in the order of 4% (∼24 Pg carbon) of the European soil organic carbon pool. Our study demonstrates quantitatively that preserving and restoring peatlands requires looking beyond peatland-specific processes and taking into account wider landscape-scale feedbacks with forest ecosystems.

Does Phenological Plasticity Help or Hinder Range Shifts Under Climate Change?

Climate warming is predicted to shift species’ ranges as previously uninhabitable environments just beyond the leading range edges become suitable habitat and trailing range edges become increasingly unsuitable. Understanding which aspects of the environment and species traits mediate these range shifts is critical for understanding species’ possible redistributions under global change, yet we have a limited understanding of the ecological and evolutionary responses underlying population spread or extinction at species’ range edges. Within plant populations, shifts in flowering phenology have been one of the strongest and most consistent responses to climate change, and are likely to play an important role in mediating population dynamics within and beyond species’ ranges. However, the role of phenological shifts, and particularly phenological plasticity, in species’ range shifts remains relatively unstudied. Here, we synthesize literature on phenology, plasticity, and adaptation to suggest ways in which phenological responses to climate may vary across species’ ranges and review the empirical evidence for and against these hypotheses. We then outline how phenological plasticity could facilitate or hinder persistence and potential consequences of phenological plasticity in range expansions, including phenological cues, shifts in correlated traits, altered species interactions, and effects on gene flow. Finally, we suggest future avenues for research, such as characterizing reaction norms for phenology across a species’ range and in beyond-the-range transplant experiments. Given the prevalence and magnitude of phenological shifts, future work should carefully dissect its costs and benefits for population persistence, and incorporate phenological plasticity into models predicting species’ persistence and geographic range shifts under climate change.

Backtracing persistent biomarker shifts to the age of onset: A novel procedure applied to men’s and women’s white blood cell counts in post-traumatic stress disorder

• Some biomarkers in mental disorders retain shifted levels long time after the onset. • A backtrace procedure for persistent shifts in cross-sectional data is presented. • It is demonstrated on leukocyte counts in post-traumatic stress disorder. • Neutrophil, lymphocyte and eosinophil counts showed the most impressive results. • The procedure opens new avenues for biomarker research in large epidemiological studies. Traumatic experiences tend to be preserved in altered biomarker profiles. These profiles can be traced back from cross-sectional data regarding the age of exposure. Consequently, the change across developmental stages, e.g. from childhood to adulthood, can also be reconstructed. This study introduces a backtrace procedure that is illustrated using white blood cell (WBC) counts in full / partial post-traumatic stress disorder (PTSD). The procedure was applied separately on men's and women's data to provide a replication of the analysis based on different subsamples. The analysis was carried out with data from the CoLaus|PsyCoLaus study (N = 5111, 2370 men and 2741 women, age range 35–88 years). It was restricted to traumatic experiences that occurred until the age of 35, i.e., the lower age limit of the sample. The WBC counts from up to two assessments were standardized, pooled and assigned to the reported age of trauma exposure. This resulted in age series for each marker, whereas the reference values were based on subjects who did not experience any trauma exposure. The backtrace procedure ascertained the peaks and troughs of the age series and determined the best-fitting critical age range surrounding each peak or trough based on the best p-value from simple t-tests. In CoLaus|PsyCoLaus, 750 participants reported trauma exposure until the age of 35, and 86 (out of 329) men and 187 (out of 421) women thereof were coded with a full or partial PTSD. Full / partial PTSD after trauma exposure in childhood was characterized by increased WBC counts (lymphocytes, eosinophils – in women also neutrophils). This pattern was partly retained during adolescence, in men due to eosinophils counts and in women due to lymphocyte counts. For exposure in young adulthood, the deviations were in the negative direction – in men with decreased basophils, in women with decreased lymphocytes and monocytes. Summarizing, the backtrace approach revealed WBC profiles in PTSD that were specific to particular developmental age stages. The strongest persistent upregulation of the immune system related to trauma exposure was traceable to childhood / early adolescence both in men and in women. Further research will show which biomarkers are similarly suitable for backtracing as WBC counts. As in PTSD, the backtrace approach could also be applied to identifying persistent biomarker profiles in other mental disorders, as well as autoimmune and other chronic diseases.

Managing exposure to volatile oil prices: Evidence from U.S. sectoral and industry-level data

This study compares the hedging abilities of sectoral and industry-level U.S. stock market for an investor who wants to protect a portfolio from oil price volatility dynamics. To this end, we employ a relatively new econometric model which is able to capture asymmetric volatility clustering, volatility persistence and regime shifts exhibited in the underlying data. We extend the volatility spillovers investigation by estimating the optimal weights for a minimum risk portfolio and computing the hedge ratio, in an attempt to evaluate optimal portfolio’ allocations and the hedging strategies’ effectiveness. Our findings provide crucial information to agents with respect to the sectors and industries of the stock market in which they need to invest during high volatility regimes in an effort to minimise risk and maximise returns. The protecting capabilities of U.S. stock sectors and industries against oil price volatility seem to be sensitive to a myriad of factors, including the various types of news (oil price changes due to normal or abnormal innovations), and the different volatility regimes (low, normal or high). Overall, this research implication can be relevant for portfolio managers and individual investors who are willing to invest in U.S. stocks.

Shift work and incidence of psychiatric disorders: The Danish Nurse Cohort study

BackgroundResearch on health effects of shift work has especially focused on somatic diseases, such as breast cancer and cardiometabolic disease, while less attention has been given to the association between shift work and mental health. MethodsWe used information on 19 964 female nurses (≥44 years) from the Danish Nurse Cohort, who reported current work schedule (day, evening, night, or rotating) at recruitment (1993/1999). In 5102 nurses who participated in both cohort waves, we defined persistent night shift work as working night shift in 1993 and 1999. We used Cox regression models to calculate hazard ratios (HRs) and 95% confidence intervals (CIs), adjusting for relevant confounders.Through linkage of cohort participants to national registers, we defined incidence of mood and neurotic disorders as first hospital contact or redeemed prescription until November 2018. ResultsWe found association between night shift work with mood disorders (HR = 1.31; 95%CI = 1.17–1.47) and neurotic disorders (1.29; 1.17–1.42), compared to day work. Associations were enhanced in nurses with persistent night shift work (1.85; 1.43–2.39 and 1.62; 1.26–2.09 for mood and neurotic disorders, respectively) and in nurses with specialist confirmed mood (1.69; 1.24–2.29) and neurotic (1.72; 1.22–2.44) disorders. Nurses with preexisting psychiatric disorders and full-time work seemed most susceptible. ConclusionsNight shift work is associated with increased risk of major psychiatric disorders. The novel suggestive findings of vulnerable groups, including nurses with a history of psychiatric disorders and full-time workers, are based on a limited number of cases, and further research is needed to confirm the results.

Workforce Entry Including Career and Technical Education and Training

This article reviews the basic patterns of employment and school enrollment for new labor market entrants in the period leading up to the Great Recession and in the decade thereafter. We find a persistent shift into four-year colleges that began during the Great Recession. At the same time, fewer youth are neither working nor enrolled in school. We see little change in occupational training programs during our study period, in program or in participation rates; in particular, rates of training provided via federal workforce development programs remain low among workforce entrants. The research literature on these programs has advanced but without large effects on policy or practice.

FeS2 nanoparticles decorated carbonized Luffa cylindrica as biofilm substrates for fabricating high performance biosensors

A high-performance microbial biosensor was fabricated with a reasonably designed biofilm substrate, where the aerogel of carbonized Luffa cylindrica (LC) was used as the scaffold for loading biofilm and FeS2 nanoparticles (FeS2NPs) were employed to modify this aerogel (FeS2NPs/GelLC). The fabricated FeS2NPs/GelLC exhibited a spring-like structure similar with that of the raw LC, which facilitated the linkage of the scaffold and promoted its mechanical strength, and further prolonged the service period of the as-prepared biosensor from few days to two months. Meanwhile, the introduced FeS2NPs improved the microbial electron transfer of the biofilm and causing an increase in the sensor's signals from 155.0 ± 2.6 to 352.0 ± 17.1 nA and a decrease in the detection limit from 0.95 to 0.38 mg O L−1 (S/N = 3) for the detection of glucose-glutamic acid (GGA). More important, the FeS2NPs had been demonstrated to have the capability for modulating a persistent shift of the microbial community with organic pollutant biodegradability. Compared with the GelLC, the FeS2NPs/GelLC exhibited a promising performance for measuring the synthetic sewage and real water samples in BOD assay and an increasing inhibition-ratio for detecting 3,5-dichlorophenol (DCP) in toxicity assay. Based on the vast resource and renewability of LC, this work pave a new avenue for developing high-performance microbial biosensors that are expected to be the engineering production.

On developing sensitive nonparametric mixed control charts with application to manufacturing industry

AbstractControl charts are designed under the normality assumption of the quality characteristic of the process. However, the normality assumption rarely holds in practice. In non‐normal conditions, parametric charts tend to display more false alarm rates and invalid out‐of‐control comparisons. The exponentially weighted moving average chart is a frequently used memory‐type control chart for monitoring the process target that only performs effectively under the smoothing parameter's small choices. This study proposes a nonparametric mixed exponentially weighted moving average‐progressive mean chart based on sign statistic (NPMEPSN) under simple and ranked set sampling schemes to address this said drawback. Normal and non‐normal distributions are included in this study to observe the proposed chart's in‐control behavior and out‐of‐control efficacy. The prominent feature of the proposed schemes is that it works efficiently in detecting small and persistent shifts in the process location corresponding to the given values of the smoothing parameter. The proposed scheme is also tested under the ranked set sampling scheme to enhance the NPMEPSN chart's performance (hereafter named “NPMEPRSN”). The performance of the proposed charts is investigated through simulations using run‐length profiles. The proposed schemes were seen to outperform other alternatives, specifically under the ranked set sampling scheme. A real data‐set related to the diameter of a piston ring is included as a demonstration of the proposal.

Effectiveness and outcomes of invasive species removal in Hawaiian streams

Despite aquatic invasive species (AIS) being a widely recognized threat to native biodiversity in streams on subtropical and tropical oceanic islands across the Pacific, AIS management has been constrained by concerns that methods of removal could result in more harm than good. In this study, we assessed the effectiveness and outcomes of combining hand-netting and streamside sequestration of native species with AIS removal via three-pass electrofishing tailored for Hawaiian Island watersheds. Removals were conducted in 13 watersheds on the island of O‘ahu following a before-after, control-impact design to assess how AIS removal and post-removal community reassembly varied by surface flow and target species of interest. We found that removals resulted in a sharp reduction in AIS densities without altering native species densities. Removal efficacy was greatest in streams with intermediate mean discharge irrespective of target group or pre-removal AIS densities. Long-term monitoring demonstrated that removals led to persistent shifts in community composition reflecting sustained reductions in AIS densities. These findings indicate that electrofishing can be a valuable tool for AIS management in Hawaiian and other subtropical Pacific island streams, so long as steps are taken to minimize potential harm to at-risk and culturally important native species.

Anatomic Double-Bundle ACL Reconstruction With Extra-articular Anterolateral Ligament Reconstruction and Internal Brace

Anterior cruciate ligament reconstruction (ACLR) with additional procedures could be necessary for patients with increased preoperative pivot shift. Double-bundle (DB) ACLR provides more footprint coverage and recreates the 2 functional anteromedial (AM) and posterolateral (PL) bundles, which are believed to give better joint function and stability than single-bundle (SB) ACLR. Internal brace augmentation with suture tape is proposed along with tendon graft in ACLR to protect the newly reconstructed ligament during rehabilitation. Additional reconstruction with anterolateral ligament (ALL) during ACLR has shown significant reduction in the level of persistent pivot shift. In Technical Note we present a modified surgical technique of combined anatomic DB ACLR and ALLR with hamstring autograft and internal brace, using button suspensory fixation device and aperture screws. The objective of this technique is to decrease residual anterior and rotational instability after ACLR and ALLR.

Light-induced persistent resonance frequency shift of MoS2 mechanical resonator

We investigate light-induced persistent resonance frequency shift on MoS2 mechanical resonators towards optically tunable nano-electro-mechanical systems with optical memory function. After the termination of light irradiation, the resonance frequency shifts downwards and the downshift is maintained for more than 20 min. This behavior is induced by trapped photogenerated holes at defects or contamination on MoS2 similar to the persistent photoconductivity. The trapped holes screen the electrostatic force acting on MoS2, which results in the reduction of the tension of MoS2. The downshift can be eliminated by applying the excess voltage pulse to MoS2 to induce Joule heating.

On the Development of Triple Homogeneously Weighted Moving Average Control Chart

To detect sustainable changes in the manufacturing processes, memory-type charting schemes are frequently functioning. The recently designed, homogenously weighted moving average (HWMA) technique is effective for identifying substantial changes in the processes. To make the HWMA chart more effective for persistent shifts in the industrial processes, a double HWMA (DHWMA) chart has been proposed recently. This study intends to develop a triple HWMA (THWMA) chart for efficient monitoring of the process mean under zero- and steady-state scenarios. The non-normal effects of monitoring characteristics under in-control situations for heavy-tailed highly skewed and contaminated normal environments are computed under both states. The relative efficiency of the proposed structure is compared with HWMA, DHWMA, exponentially weighted moving average (EWMA), double EWMA, and the more effective triple EWMA control charting schemes. The relative analysis reveals that the proposed THWMA design performs more efficiently than the existing counterparts. An illustrative application related to substrate manufacturing is also incorporated to demonstrate the proposal.

Major and persistent shifts in below-ground carbon dynamics and soil respiration following logging in tropical forests.

Soil respiration is the largest carbon efflux from the terrestrial ecosystem to the atmosphere, and selective logging influences soil respiration via changes in abiotic (temperature, moisture) and biotic (biomass, productivity, quantity and quality of necromass inputs) drivers. Logged forests are a predominant feature of the tropical forest landscape, their area exceeding that of intact forest. We quantified both total and component (root, mycorrhiza, litter, and soil organic matter, SOM) soil respiration in logged (n=5) and old-growth (n=6) forest plots in Malaysian Borneo, a region which is a global hotspot for emission from forest degradation. We constructed a detailed below-ground carbon budget including organic carbon inputs into the system via litterfall and root turnover. Total soil respiration was significantly higher in logged forests than in old-growth forests (14.3±0.23 and 12.7±0.60MgCha-1 year-1 , respectively, p=0.037). This was mainly due to the higher SOM respiration in logged forests (55±3.1% of the total respiration in logged forests vs. 50±3.0% in old-growth forests). In old-growth forests, annual SOM respiration was equal to the organic carbon inputs into the soil (difference between SOM respiration and inputs 0.18MgCha-1 year-1 , with 90% confidence intervals of -0.41 and 0.74MgCha-1 year-1 ), indicating that the system is in equilibrium, while in logged forests SOM respiration exceeded the inputs by 4.2MgCha-1 year-1 (90% CI of 3.6 and 4.9MgCha-1 year-1 ), indicating that the soil is losing carbon. These results contribute towards understanding the impact of logging on below-ground carbon dynamics, which is one of the key uncertainties in estimating emissions from forest degradation. This study demonstrates how significant perturbation of the below-ground carbon balance, and consequent net soil carbon emissions, can persist for decades after a logging event in tropical forests.

What do we know about cryptocurrency? Past, present, future

PurposeThe authors make a fundamental initial effort to conduct a systematic review analysis on “cryptocurrency,” mainly to analyze the way it has been changing the “stereotype” financial transactions, and also identify the probable unexplored research avenues on this innovative investment regime. The study aims to draw the landscape of the current state, prospects, challenges, trends and possible agendas of cryptocurrency in the global market.Design/methodology/approachUsing a quali-quantitative approach widely known as meta-literature review, the synthesis analysis on “cryptocurrency” is conducted. Methodologically, the authors review and analyze the most recent and relevant papers preferably published between 2016 and 2020 in leading business and finance journals of ISI Web of Science (ISI WOS) through bibliometric analysis particularly coupled with content analysis.FindingsThe findings of the meta-analysis summarize the relevant stylized facts of the cryptocurrency market: distinctive features of blockchain technology, decentralized payment method, low-cost facility, ensuring pseudo-anonymity, independence from central authority, double spending attack protection, organic and instantaneous nature, among others. In addition, the analysis identified several future research regimes: pricing model, prospect of investment regime, hedging properties, volatility dynamics, information asymmetry, underlying risk factors and bubble-like nature in global cryptocurrency market.Practical implicationsThis academic novelty significantly contributes to enhance our knowledge on the current state-of-the-art of digital finance, outlines the research agenda and eventually provides important investment implications for financial managers, research analysts, investors, market practitioners, regulatory compliance professionals and policymakers. Therefore, the findings shed the lights on new investment opportunity in the global market.Originality/valueCryptocurrency, virtual currency or digital asset having cryptography for idiosyncratic security features, seems to be a persistent paradigm shift in the digitalized financial system. Despite the continuing growth, the academic research on cryptocurrency is still at nascent stage, particularly because researchers did not deeply draw attention at this financial innovation. In addition, the authors argue that none of the earlier studies yet conducted a meta-analysis on this latest investment regime. Therefore, this review study is the initial attempt to fill up the gap in the finance literature.

The Invasion Ecology of Sleeper Populations: Prevalence, Persistence, and Abrupt Shifts

ABSTRACTIt is well established that nonnative species are a key driver of global environmental change, but much less is known about the underlying drivers of nonnative species outbreaks themselves. In the present article, we explore the concept and implications of nonnative sleeper populations in invasion dynamics. Such populations persist at low abundance for years or even decades—a period during which they often go undetected and have negligible impact—until they are triggered by an environmental factor to become highly abundant and disruptive. Population irruptions are commonly misinterpreted as a recent arrival of the nonnative species, but sleeper populations belie a more complex history of inconspicuous occurrence followed by an abrupt shift in abundance and ecological impact. In the present article, we identify mechanisms that can trigger their irruption, and the implications for invasive species risk assessment and management.

Transient ACE (Angiotensin-Converting Enzyme) Inhibition Suppresses Future Fibrogenic Capacity and Heterogeneity of Cardiac Fibroblast Subpopulations.

Transient ACE (angiotensin-converting enzyme) inhibition in spontaneously hypertensive rats is known to protect against future injury-induced cardiac inflammation, fibrosis, and dysfunction; however, the mechanisms of protection have not been delineated. Here, we used single-cell RNA sequencing to test the hypothesis that transient ACE inhibitor treatment would induce a persistent shift in cardiac fibroblast subpopulations. Adult male spontaneously hypertensive rats (11 weeks old, hypertensive with cardiac hypertrophy) were treated for 2 weeks with an ACE inhibitor, enalapril (30 mg/kg per day, PO), or water (untreated spontaneously hypertensive rats) followed by a 2-week washout period (n=7/group). Cardiac fibroblasts were isolated from the left ventricle and subjected to single-cell RNA sequencing. Nine clusters of fibroblasts were identified, with 98% of cells in clusters 0 to 6. The transient treatment produced significant changes both within and across clusters. Cluster 1 depicted a highly fibrogenic gene profile, with cluster 6 serving as a gateway to cluster 1. Transient ACE inhibition depleted the gateway and expanded cluster 0, which was the least fibrogenic profile. Moreover, within cluster 1 fibroblasts, ACE inhibition reduced expression of individual fibrosis genes (eg, COL1A1, COL3A1, and FN1; all P<1×10-35). Clusters 2 to 5 reflected proliferative, moderately fibrogenic, translationally active, and less inflammatory subsets of fibroblasts, all of which exhibited attenuated fibrogenic gene expression after transient ACE inhibition. In conclusion, transient ACE inhibition shifts cardiac fibroblast subpopulations and degree of activation resulting in an overall reduced fibrogenic phenotype.

Working From Home During COVID-19 and Beyond: Survey Evidence From Employers

Based on survey responses from more than 1,700 managers in Germany, this study elicits employers’ perceptions of working from home during COVID-19 and their long-term expectations for the time after the pandemic. Based on employers’ forecasts of the share of employees working from home post-COVID, the within-firm intensity of the expected shift is quantified. Many firms expect a persistent shift towards working from home induced by the COVID-19 pandemic. Larger firms and firms with pre-COVID use of working from home are most likely to expect a persistent and intensive shift. As the empirical results indicate, underlying mechanisms for the expected shift might include learning effects facilitating an improved perception of working from home, investments in physical and human capital, a general push in firms’ digital progress, and the fact that most firms do not observe a reduction in productivity due to working from home during COVID-19.

Inflation Persistence, Monetary Regimes and Credibility: A Long-term Perspective

Inflation persistence or ‘inertia’ has important consequences for monetary policy. Inflation which does not get eliminated today tends to persist entailing higher costs in the future. In turn, a monetary regime can exert significant influence on inflation persistence by its credibility and responses in the face of inflationary shocks. In this study, we use a flexible, time-varying parameter approach to analyze inflation persistence in the United Kingdom and United States during 1880-2016. Our results indicate strong evidence for time-varying inflation persistence in conjunction with shifts in monetary policy regimes. Further, we show that credibility of the monetary regime significantly influences inflation persistence observed under the regime, such that higher (lower) regime credibility leads to lower (higher) inflation persistence. Finally, we argue that institutional framework such as adherence to a rule-based policy, provision of a nominal anchor, policy autonomy etc., and the actions of monetary authorities are vital for understanding the shifts in regime credibility and inflation persistence across time. Overall, our findings indicate that appropriate design and credible conduct of monetary policy is crucial for achieving and sustaining price stability.

Safe Femoral Fixation Depth and Orientation for Lateral Extra-Articular Tenodesis in Anterior Cruciate Ligament Reconstruction.

Background:Patients who undergo anterior cruciate ligament (ACL) reconstruction (ACLR) can have a persistent postoperative pivot shift. Performing lateral extra-articular tenodesis (LET) concurrently has been proposed to address this; however, LET femoral fixation may interfere with the ACLR femoral tunnel, which could damage the ACL graft or its fixation.Purpose:To evaluate the safe maximum implant or tunnel depth for a modified Lemaire LET when combined with ACLR anteromedial portal femoral tunnel drilling and to validate the safe LET drilling angles to avoid conflict with the ACLR femoral tunnel.Study Design:Descriptive laboratory study.Methods:Twelve fresh-frozen cadaveric knees were used. With each knee at 120° of flexion, an ACLR femoral tunnel in the anteromedial bundle position was created arthroscopically via the anteromedial portal using a 5-mm offset guide, a guide wire, and an 8-mm reamer, which was left in situ. A modified Lemaire LET was performed using a 1 cm-wide iliotibial band strip harvested with the distal attachment intact, to be fixed in the femur. The desired LET fixation point was identified with an external aperture 10 mm proximal and 5 mm posterior to the fibular collateral ligament’s femoral attachment, and a 2.4-mm guide wire was drilled, aiming at 0°, 10°, 20°, or 30° anteriorly in the axial plane and at 0°, 10°, or 20° proximally in the coronal plane (12 different drilling angle combinations). The relationship between the LET drilling guide wire and the ACLR femoral tunnel reamer was recorded for each combination. When a collision with the femoral tunnel was recorded, the LET wire depth was measured.Results:Collision with the ACLR femoral tunnel occurred at a mean LET wire depth of 23.6 mm (range, 15-33 mm). No correlation existed between LET wire depth and LET drilling orientation (r = 0.066; P = .67). Drilling angle in the axial plane was significantly associated with the occurrence of tunnel conflict (P < .001). However, no such association was detected when comparing the drilling angle in the coronal plane (P = .267).Conclusion:Conflict of LET femoral fixation with the ACLR femoral tunnel using anteromedial portal drilling occurred at a mean depth of 23.6 mm but also at a depth as little as 15 mm, which is shorter than most implants. When longer implants or tunnels are used, the orientation should be directed at least 30° anteriorly in the axial plane to minimize the risk of tunnel conflict, bearing in mind the risk of joint violation.Clinical Relevance:This study provides important information for surgeons performing LET in combination with ACLR anteromedial portal femoral tunnel drilling regarding safe femoral implant or tunnel length and orientation.

STRATEGIES USED TO TEACH GRADE 11 FINANCIAL ACCOUNTING IN ONE DISTRICT IN SOUTH AFRICA

Accounting curriculum is constantly changing because of the persistent shifts in the discipline emanating from the developments in the profession. This paper explores teaching strategies used by accounting teachers to teach Grade 11 Financial Accounting in one district in South Africa. A qualitative case study was used to allow for an in-depth understanding of the strategies used to teach Financial Accounting by talking to and observing four Accounting teachers directly. The Grade 11 Accounting teachers were conveniently and purposively sampled from four schools. Semi-structured individual interviews and lesson observations were used as data generation methods. The data were then analyzed by identifying various themes that respond to the research question. The findings of the study revealed that teachers understand that Accounting is a unique practical subject with its own language. As a result, they used a variety of teaching strategies to enhance teaching and learning of the subject. What emerged from the findings is that, because of sequencing of knowledge, some topics build on each other and cannot be taught without first teaching other topics. Teachers insisted on determining learners understanding of foundational or prerequisite knowledge that was crucial in reinforcing learning of new concepts. Because teachers regarded Accounting is a practical subject that necessitates regular practice, teachers used frequent and different assessment tasks to consolidate learning of new knowledge.