This paper proposes a robust generalised dynamic inversion (GDI) control system design with adaptive neural network (NN) estimation for spacecraft attitude tracking under the absence of knowledge of the spacecraft inertia parameters. The robust GDI control system works to enforce attitude tracking, and the adaptive NN augmentation compensates for the lack of knowledge of the spacecraft inertia parameters. The baseline GDI control law consists of a particular part and an auxiliary part. The particular part of the GDI control law works to realise a desired attitude dynamics of the spacecraft, and the auxiliary part works for finite-time stabilisation of the spacecraft angular velocity. Robustness against modeling uncertainties and external disturbances is provided by augmenting a siding mode control element within the particular part of the GDI control law. The singularity that accompanies GDI control is avoided by modifying the Moore-Penrose generalised inverse by means of a dynamic scaling factor. The NN weighting matrices are updated adaptively through a control Lyapunov function. A detailed stability analysis shows that the closed loop system is semi-global practically stable. For performance assessment, a spacecraft model is developed, and GDI-NN control is investigated for its attitude control problem through numerical simulations. Simulation results reveal the efficacy, robustness and adaptive attributes of proposed GDI-NN control for its application to spacecraft attitude control.

The question of which English to teach has been an issue since the late-20th-century advent of the world Englishes (WE) paradigm. In the early 1990s, Quirk and Kachru conducted one of the most significant debates about this controversial issue in applied linguistics. Quirk (1990) argued that only standard native varieties that have no grammar deviations and adhere to mainstream vocabulary usage should be taught in order to counter the contamination of English resulting from tolerance of variations, observing that he was ‘not aware of there being any institutionalized nonnative varieties’ (p. 6). In contrast, Kachru (1991) argued that language variation due to language contact is a common sociolinguistic phenomenon, so Outer Circle varieties are not substandard or deficit languages. Therefore, he contended, traditional notions of standardization are no longer acceptable. He recommended that multiple localized varieties should be taught in Outer Circle contexts because they reflect learners’ linguistic and cultural identity. In relation to Kachru's argument, English as a lingua franca (ELF) has developed as a recent paradigm in TESOL. Kirkpatrick (2012) has argued that a lingua franca approach to English language teaching (ELT) helps prepare learners to use the language successfully in multilingual settings like ASEAN countries, where English functions as a lingua franca. In these settings, the teaching of ELF, in which speakers retain their own grammatical forms, phonological features, and pragmatic norms, needs to be promoted (Kirkpatrick 2011; Kirkpatrick, Subhan & Walkinshaw, 2016).

We examine the association between margin requirements and the market’s efficiency in incorporating firm-specific and market-level public news. Combining the Fed’s 22 changes in margin requirements with a hand-collected sample of earnings announcements between 1934 and 1975, we show that higher margin requirements induce greater delay in incorporating earnings information into prices. We draw similar conclusions when we analyze the Hou and Moskowitz (2005) price delay measure, as well as indirect measures of leverage constraints over recent years. Further tests suggest that, despite the Fed’s expressed intent to curtail excess speculation, higher margin requirements restrict trading by arbitrageurs more than noise traders.

In India, school psychology is an emerging field of study. The Central Board of Secondary Education (CBSE) has mandated the appointment of school counsellors to boost mental health through counselling, life-skills education, and career guidance. In the present study, the school counsellor implemented a five-minute meeting to quickly interact with students to promote their wellbeing. Using universal sampling, data were collected from 78 students using a Google survey form at one of the leading private schools in Meerut city of Uttar Pradesh State, India. The findings of the study indicated an improvement in the personal-social and school-career domains of students’ wellbeing. Approximately 72% of students reported being happy, and 58% shared being friendly (personal-social domain). Nearly 68% of students reported doing well in the school (school-career domain). Moreover, 65% of students expressed willingness to meet with the counsellor. The initiative received an overwhelmingly positive response (82%), indicating that it has increased the value of support for these students. This initiative provided an opportunity for both the counsellor and students to get to know each other and allowed the counsellor to plan individual and group counselling sessions as needed. Prospective studies could employ robust methodology with a larger sample size to evaluate the effects of this initiative on mental health outcomes.

In this paper, the Hill Valley (HV) approach is applied to the drifting masses or agents in the basic Gravitational Search Algorithm (GSA) for the path planning of humanoid robots. The drift in lighter masses toward the heavier mass creates a localized area, where the probability of obtaining a globally optimal solution is very high. So, the present work is focused on exploiting the area to tackle local optima and provide the best steering angle for the humanoids to navigate. The HV approach is applied to the basic GSA model, at the later stages, to improve the overall computational time and cost. The robustness of the proposed controller was tested in both simulation and experimental environments and compared with the previous research. The results obtained from the proposed controller showed a significant improvement in the overall path length and time taken. Path smoothness was also given equal importance during path planning to ensure stability. The multi-robot navigational scheme was performed using the Dining Philosopher’s model to avoid dynamic collision among the humanoids. The percentage deviation in the results was within the acceptable limits. To further check the effectiveness of the proposed technique, the proposed approach was compared with the vision-based navigation in danger space.

How do Black Americans practice a politics of racial group uplift while balancing their individual material interests? Traditionally, scholars have drawn on linked fate theory. However, more recent work argues that Black Americans remain politically unified because they feel race-based social pressure to conform more than a sense of linked fate. Employing a novel research design, I use the competitive reality television series, Survivor, to observe and analyze Black group-based decision-making. Through an inductive thematic content analysis of 13 Survivor episodes, I identified five themes in Black players’ discussions of racialized social obligations when playing the game—what I call narratives of racial duty. Claims that emerged in this storytelling suggested that similar to the political world, Black Survivor contestants were keenly aware of the racialized social obligations for them as contestants in the game. For some, this reality felt like a burden. For others, it presented an opportunity. These reactions led some Black players to work together and others to construct a rationale for defecting from race-based alliances. I conclude by making the case that analyzing entertainment programs offers race and politics scholars a new site for identifying common scripts used to adhere to (and sidestep) racialized social norms.

In the second half of the eighteenth century, Dutch bankers channeled investors’ funds to sugar and coffee plantations in the Caribbean, Surinam in particular. Agency problems between plantation owners, bankers, and investors led to an arrangement called negotiaties. Bankers oversaw plantations’ cash flows and placed mortgage debt with investors. We demonstrate how this securitization arrangement worked using market-wide data and detailed records from banker F. W. Hudig. During the boom, debt contracts and their securitization were an effective solution for planters, bankers, and investors. However, the market crashed after an oversupply of credit. This led to inefficient restructuring due to debt overhang.

Acid–base disequilibrium is a contributor to cancer development because it affects molecular activities such as insulin-like growth factor 1 levels and adiponectin production. However, evidence of an association of diet-induced acid–base imbalance with colorectal cancer (CRC) is limited. We examined whether colorectal carcinogenesis is attributable to a diet with a high acid load. We recruited a total of 923 CRC cases and 1846 controls at the National Cancer Center in Korea for inclusion in a case–control study. We collected information on nutrient intake and specific clinical parameters of CRC by using a semiquantitative FFQ and medical records, respectively. Potential renal acid load (PRAL) and net endogenous acid production (NEAP) were used to estimate diet-dependent acid load. We used an unconditional logistic regression model to analyse the association. Dietary acid load scores had a positive association with the odds of CRC (OR = 2·31 (95 % CI 1·79, 2·99) and OR = 2·14 (95 % CI 1·66, 2·76) for PRAL and NEAP, respectively, Pfor trend < 0·001). A stronger positive association was observed for females (OR = 3·09, 95 % CI 1·93, 4·94) than for males (OR = 1·71, 95 % CI 1·27, 2·31). Furthermore, acidogenic diets appeared to affect rectal cancer more strongly than colon cancer in females. Our study contributes to reinforcing epidemiological evidence regarding a detrimental effect of acidogenic diets on colorectal carcinogenesis. Thus, it is important to pay attention to the balance of acidogenic (e.g. poultry and red meat) and alkalinogenic foods (e.g. fruits and vegetables) in CRC prevention, especially for females.

Noonan syndrome is a multi-system genetic disorder and patients may suffer from hypertrophic cardiomyopathy. Previous studies have identified electrocardiographic features that may support a diagnosis of Noonan syndrome. In this two-centre retrospective study, we analysed typical Noonan syndrome-related electrocardiographic features in 30 patients with Noonan syndrome with hypertrophic cardiomyopathy and compared these with the electrocardiographic features in 15 children with sarcomeric hypertrophic cardiomyopathy. Typical Noonan syndrome-related electrocardiographic features are a negative aVF, small left precordial R-waves, large right precordial S-waves, and abnormal Q-wave. We also analysed electrocardiographic features of hypertrophic cardiomyopathy: ST-segment abnormalities and T-wave abnormalities. A negative aVF was seen in 83% of patients with Noonan syndrome-related hypertrophic cardiomyopathy in contrast to 27% of patients with primary sarcomeric hypertrophic cardiomyopathy (p < 0.001). An extreme QRS axis in the north-west was seen only in patients with Noonan syndrome-related hypertrophic cardiomyopathy. This QRS axis deviation is likely to be determined by the Noonan syndrome-related hypertrophic cardiomyopathy and not by the type of hypertrophic cardiomyopathy. There were no differences between the two groups in the frequency of large right precordial S-waves and small R-waves in the left precordial leads V5 and V6. However, an abnormal R/S ratio was more often seen in patients with Noonan syndrome-related hypertrophic cardiomyopathy (p < 0.001). Pathologic Q-waves were seen statistically more frequently in patients with sarcomeric hypertrophic cardiomyopathy (p = 0.009). The occurrence of ST-segment and T-wave pathology did not statistically differ between the two groups. Electrography can be of use in differentiating sarcomeric hypertrophic cardiomyopathy from Noonan syndrome-related hypertrophic cardiomyopathy.