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The paper discusses the types of singular points occurring in the first‐order ordinary differential equation which describes compressible viscous flow in a channel or stream tube of varying cross‐sectional area. The treatment is one‐dimensional, viscosity being allowed for by assuming a tangential stress acting on the circumference. The resulting patterns of the integral curves arc examined. It is shown that for convergent‐divergent channels whose profile has no point of inflexion, the singular point is a saddle point, as is the case in frictionlcss flow. However, the sonic section or the section of highest or lowest Mach number do not coincide with the throat but arc situated downstream of it in the divergent portion. The slopes of the integral curves which pass through the sonic section arc evaluated. When the convergent‐divergent channel has a point of inflexion in its profile there may be two singular points, the first being a saddle point and the second cither a spiral point or a nodal point. It is shown that spiral points are more likely to occur than nodal points and that, when they occur, there is no radical change in the Mach number variation along the channel due to friction. On the other hand, the existence of a nodal point admits the possibility of a continuous transition from supersonic to subsonic How in which the Mach number at exit may vary within certain limits, the Mach number in the second sonic section remaining always equal to unity. In all types of flow there arc portions of the channel over which the influence of friction outweighs that of area change.

IN the preliminary calculation for the design of a gas turbine or turbocompressor it is necessary to assume a value of the reheat factor R. The contemporary development of gas turbines and rotary compressors has aroused renewed interest in this quantity, which was studied earlier in connexion with steam turbines (refs. 1, 2, 7, 8 and 9). The paper contains an analysis of this value for a gaseous working fluid under appropriate assumptions; it is first calculated for an infinite number of stages with constant and variable specific heats; secondly, exact and approximate formulae are derived for finite numbers of stages of expansion and compression respectively and a method of estimating the heat recovery in turbines for working fluids with variable specific heats is indicated. Similar problems were considered in ref. 10 and the subject matter of Part III was presented to the Aeronautical Research Council (ref. 6).

Purpose: This work provides an empirical analysis of investor behaviour's simultaneous influence due to the surprise effect caused by COVID-19 cases and government responses to market risk. This analysis compares tourism assets risk with other sectors and different types of investors' assets and categories in Europe.

Design: The paper applies an ARIMA with a GARCH model to predict conditional volatility of models for market uncertainty. Nonlinear models, factor analysis and time series linear regression for stationary variables in first differences are applied to predict market uncertainty.

Findings: We demonstrate that market risk does not arise from COVID-19 cases but instead from the surprise effect, as the market accurately predicts future cases. Only the volatility of the sectors Travel, Airline, and Utility are influenced by both surprise effect and government response, but only the travel sector reveals an interaction effect with both government response effort and surprise effect.

Originality: The article mutually studies the simultaneous interactions among investor behaviour due to the surprised effect caused by COVID-19 and government responses to the pandemic and the influence on professional investors' volatility in two asset types and between different sectors.

Practical implications: With this model and results, investors and financial service providers may verify whether or not government intervention during pandemic periods is effective in reducing uncertainty and risk levels on sectors, types of investors and different sorts of assets.

This paper uniquely aims to triangulate the effects of the COVID-19 pandemic, government financial intervention (GFI) policies and power distance (PD) culture on returns of equity indices during the COVID-19 epidemic in the world's equity markets.

The research employs panel data regression analysis using 1,937 observations from 19 developed and 42 developing countries. The data employed contain daily registered COVID-19 cases, global equity market index prices, financial intervention policies introduced by governments and Hofstede's cultural dimension measure of PD.

The authors find that investors certainly react negatively to the number of confirmed COVID-19 cases reported, that GFI policies indeed reinforce investors' expectations of policymakers' dedication to stabilize the economy during the COVID-19 pandemic and that equity investors in high PD cultures overreact to GFI news, resulting in more positive stock returns. The authors discover a difference between developed and developing countries in terms of the effect of GFI policies and PD on equity returns.

Results suggest that investors react negatively to the daily registered COVID-19 cases. The authors find that financial intervention policies introduced by governments reinforce investors' outlooks of policymakers' commitment to stabilize local stock markets during the coronavirus pandemic. The results confirm that equity market investors in PD cultures overreact to financial intervention news, thus resulting in more positive stock returns.

The paper provides three original contributions. First, it helps us to understand the single effect of the COVID-19 and financial intervention policies introduced by governments on returns of the global equity market. Second, it examines the possibility of a two-way joint effect between the COVID-19 and financial intervention policies introduced by governments and the COVID-19 and differences in countries characterized by a PD culture concerning stock market returns. Third, it investigates the possibility of a three-way interaction effect between the COVID-19 contagion, financial intervention policies introduced by governments and culture on returns of equity markets.

The authors' findings are valuable to researchers, investors and policymakers. Culture and finance scholars can now observe the role of Brown et al.'s (1988) uncertain-information hypothesis with reference to the effect of the COVID-19 and financial interventions policies introduced by governments on returns of equity markets. This is because the authors' findings underline that since investors' uncertainty declines with daily registered numbers of COVID-19 cases, the introduction of GFI policies function as a neutralizing device to re-establish investors' expectations to equilibrium. Consequently, stock market returns follow a random walk that is free from the negative effect of the COVID-19. The authors' work is likely to advise equity investors and portfolio managers about the extent to which major exogenous economic events such the outbreak of global diseases, financial interventions policies introduced by governments and differences in countries' PD culture can individually and jointly influence the return of the world's equity markets. Investors and portfolio managers can employ the authors' results as a guideline to adjust their investment strategy based on their investment decision strategy during global pandemics. Policymakers aiming to introduce financial intervention policies to stabilize their stock market returns during global pandemics can benefit from our results. They can observe the full effect of such policies during the current COVID-19, and subsequently be better prepared to choose the most effective form of financial intervention policies when the next pandemic strikes, hopefully never.

According to the Government Response tracker (oxCGRT) index, the strictest policy responses to the coronavirus pandemic from January 2020 to May 2022 belong to Italy, China, Hong Kong, Greece, Austria, Peru, Singapore and Malaysia. The main question is: “this level of strictness has been able to reduce the uncertainty of the stock market?”

To achieve this goal, the authors investigated the effect of oxCGRT index, and the growth rate of COVID-19 confirms cases on stock market uncertainty from January 2020 to May 2022 in the GARCH, EGARCH and TGARCH models.

Among these countries, the oxCGRT index has reduced uncertainty in the stock market only in Malaysia and Singapore. This result says an appropriate pattern of applying government policy responses is more important than the degree of stringency.

The study will contribute to the existing literature by examining the impact of the comprehensive oxCGRT index on the uncertainty of the stock market.

This chapter aims at providing insight into how social mixing plays out in the Transvaal neighborhood in Amsterdam — a neighborhood which has gone through various rounds of urban renewal — in the context of nationwide polarization between native-Dutch and Moroccan-Dutch.

This chapter is based on research with a neighborhood focus — daily interactions, urban renewal, and use of public space — which took place during 2007–2010. Methods used include participant observation, semistructured interviews, and focus groups.

The physical renewal implies renovating and pulling down social housing, and building new social or owner-occupier housing. This study provides insight into how residents of different ethnic and income backgrounds live together in the neighborhood, also taking into account the impact of social polarization at the national level.

By knowing how people with different ethnic and class backgrounds live together in Transvaal neighborhood, it contributes to the formulation of evidence-based policies for the improvement of social cohesion, livability, safety of the neighborhood, and social capital of local residents.

This study looks at social mix in the context of national-level social polarization between native-Dutch and Moroccan-Dutch. This creates a new viewpoint seen against how the general literature on renewal and social mixing tends to do two things: firstly it usually explicitly or implicitly is also a tenure mix strategy, and secondly the policy focus of the social mix is usually around class issues, that is, the mixing of poor social housing tenants with richer owners.

This article aims to introduce practical based criteria for effective organizational communication.

The subject scope for this article is corporate communication. The study is based on literature reviews and a qualitative study, entailing the basic principles of the phenomenological approach, with 20 subjects.

Four additional criteria for effective corporate communication surfaced: responsible; professional; concise; and sincere.

The studies reviewed, although in‐depth, apply to a small sample in one metropolitan environment, which makes generalization among different cultures riskier.

Organizational managers may use these findings to reflect on their communication strategies and improve them, where necessary, on the basis of the findings of this study.

The paper's value lies in the four additional criteria found as a result of reflections from members of the corporate workforce, after having been exposed to a course on organizational communication, and therefore, existing criteria in literature. The additional criteria may be considered important for corporate workers, and should therefore not be ignored by managers.

This paper aims to investigate the risk-return and volatility spillover within the Tunisian stock market during the COVID-19 pandemic analyzing both the Islamic and conventional stocks’ performance.

Both symmetric (GARCH and GARCH-M) and asymmetric (Threshold GARCH and Exponential GARCH) models are used to analyze the market returns and volatility response. Standard and Poor’s (S&P) index has been used to test both the Islamic and conventional stocks within the Tunisian stock market.

The findings suggest that both Tunisia Islamic and conventional stock markets are highly persistent; however, the conventional stock index showed a negative return spillover on the Islamic stocks during the pandemic. The conventional stock index has also shown a higher exposure to risk for a lower amount of return, and evidence of potential diversification benefit between both indexes was found during the pandemic, whereas the Islamic market showed a positive leverage effect, indicating a positive correlation between past return and future return; the conventional index implied a negative leverage effect.

The value of this paper emerges in studying three main aspects that are specific to the Tunisian stock market. This includes COVID-19 effect of return spillovers, volatility transmission across both conventional and Islamic stock market within the local financial market.