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Introduction The transformation function for two‐sector production models has been used extensively in the international trade and general equilibrium literature. It has been derived both graphically and mathematically from individual sector production functions that are assumed to be linearly homogeneous. The result has been a convex set possessing first derivatives that have frequently been used. However, there seems to be a lack of research on further properties attributable to the transformation function. The purpose of this paper is to analyze these additional properties. We begin by proving that the transformation function is linearly homogeneous in all of its arguments. We then derive the standard first derivatives of the transformation function providing their usual economic interpretation. Finally, we conclude by deriving and interpreting the second‐order derivatives of the transformation function.

The purpose of this paper is to analyze the extent to which major US airlines respond to one another in quality of service improvements.

Utilizing monthly data, the authors estimate a five-equation vector autoregressive model to determine which airline leads or follows others in quality of service improvements.

This study found that the five major airlines make interrelated decisions when responding to customer complaints concerning flight problems, over-sales, reservations, ticketing, boarding, and customer service. Every airline either responds to or influences the changes in customer complaints faced by at least one other airline, while some airlines do both. However, only one such relationship was found when examining if airlines change the percent of flight delays they have control over in response to changes in flight delays faced by another airline.

The number of passenger complaints against an airline can be influenced by the airline, as can the number of carrier-caused flight delays. The industry leaders in responsiveness to consumer complaints are US Airways and United. However, airlines do not, as a group, respond to the carrier-caused delays of their competitors. The prescription to improve airline service vis-à-vis flight delays is simple: tell passengers why flights are delayed. To protect or gain market share, airlines would compete for customers by minimizing flight delays in a similar manor to how they respond to customer complaints.

No other paper that the authors are aware of has addressed the issue of identifying leaders and followers in the US airline industry regarding changes in service quality as reflected by changes in passenger complaints and flight delays.

Time is an important determinant of factor demand and supply elasticities in producer theory. The typical textbook distinction between the short‐run and the long‐run focuses upon the ability of the decision‐maker to adjust fixed factors. Indeed, the length of the firm's planning horizon may be identified with the degrees of freedom available to the firm; i.e. the number of factors that can optimally be adjusted to a changing economic environment. The purpose of this note is to illustrate use of the envelope theorem to recover a generalized Samuelson‐Le Chatelier principle in a simple and elegant manner. In particular, we will show how a monopolist's derived factor demand elasticities may be ordered by the length of the planning horizon. Thus the economically appealing and intuitive notion that the monopolist's factor demand decisions will be more responsive to price changes, the greater the flexibility in utilizing fixed factors will be given an analytically rigorous, though quite simple, demonstration utilizing duality theory and the well‐known envelope theorem.

This paper presents rankings of economics journals taken from a recent survey of economics department heads. Different rankings were derived for those with different research areas and those associated with different types of academic institutions. It was found that rankings were quite similar for all respondents.

This paper analyzes the welfare implications of price regulation in competitive market structures. The analysis is performed in a general equilibrium framework where individuals are producers of the goods they consume. These produced goods in the economy are designated as good A, good B, and q, which represents quality per unit of A. The first half of the paper is devoted to the competitive equilibrium and the effects of price regulation on product quality. The second half of the paper analyzes the welfare effects of price regulation when the economy consists of both non‐identical and identical consumers. It is shown that regulation may be a Pareto superior move in the absence of a market and price for quality.

Surface roughness has been proved to be influencing the running-in wear of machined components under dry and lubricated sliding conditions. Zinc dialkyl dithiophosphate (ZDDP) is widely used as an anti-wear additive, which reduces the wear by the formation of a tribofilm on the surface (Spikes, 2004). Factors such as temperature, sliding distance, etc. influence the formation of the film. A significant reduction in the power loss due to friction and wear is possible if a synergy is attained between surface roughness effects and the effectiveness of the tribofilm. The present work aims to study the influence of surface roughness and ZDDP addition on the formation and removal of the tribofilm under high contact pressures.

Samples were prepared by machining. Surface roughness was varied by varying the milling parameters. A reciprocating friction and wear test machine with a ball-on-flat geometry was used for the study. Tests were performed with mineral base oil and base oil added with 1 per cent by weight ZDDP under different operating parameters. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) with energy dispersive X-Ray spectroscopy (EDS) analysis were conducted to study the surface morphology of the tribofilm.

A quasi-steady-state analysis conducted showed that the wear rate was much lower when tested with base oil containing ZDDP after about 65 min. AFM analysis confirmed the presence of chemically reacted films on the surface. SEM analysis revealed agglomeration of crystal like glassy phosphates. However, high contact pressures at the interface caused the removal of the films resulting in variations in the coefficient of friction. A comparison of the wear rates among the samples of different roughness values tested at 100°C showed that the anti-wear performance of ZDDP was not effective due to high contact pressures.

The findings in this study regarding the tribofilm formation with ZDDP additive and its failure due to high contact pressures will be beneficial for further investigation on wear resistant boundary films developed under such extreme conditions.

The purpose of this paper is to describe and analyze an Arizona university’s educational leadership program and the revisioning/restructuring process that program faculty have engaged in to ensure that the program provides aspiring school leaders with the conceptual knowledge, dispositions, and skills necessary to transform their schools in ways that directly address the needs of Arizona’s increasing diverse student population and ensures equitable and excellent educational opportunities for every student.

Through a narrative inquiry approach (Clandinin, 2006), this study examined the Sonoran Leadership Academy and how the program faculty prepared aspiring school leaders to meet the needs of Arizona’s changing demographics.

The findings indicate that the program faculty have been able to work collaboratively to establish an ecological framework of transformative leadership to develop aspiring school principals’ dispositions to tackle systemic racism and practices associated with deficit thinking and low expectations of diverse student populations. By more explicitly and seamlessly weaving concepts and skills related to race, racism, and the structures and cultures that can either perpetuate or disrupt inequitable treatment of diverse student populations throughout all of the courses and experiences of the program, the program faculty made substantial progress in supporting their students to meet the program outcomes around equity and excellence and transformative leadership.

The knowledge generated from this study is limited to one specific educational leadership program in Arizona, but the conceptual framework emerged from the study has implications on how educational leadership programs can embark on a similar revision effort to ensure that leadership studies is responsive to the issues of race and racism in the context of schooling and demographic change.

The results of this study will operationalize a new conceptual model to demonstrate concrete effective teaching practices on ways to prepare school leaders for diversity and demographic change.

By the year 2050, it is estimated that white Americans will no longer make up the majority of the population in the USA. Since the school system has historically been envisioned as the bedrock of democracy, there is a pressing need for the educational system to respond to issues related to this demographic change and to prepare effective school leaders to establish conditions of equity and excellence for all children across multiple forms of diversity in their local schools.

This study contributes to scholarship in several ways. First, it introduces the field of educational leadership to an antiracist framework for critical race leadership studies and principal preparation. Second, it methodologically contributes to educational studies by using narrative inquiry to understand the experiences of those who are situated in the research context. Third, the paper connects theory to practice by identifying specific strategies on how to revise a program to meet the needs of diverse K-12 student populations, and how these efforts are connected to the university classrooms in the ways school leaders are prepared for transformative leadership.

The purpose of this paper is to study the effect of new heterocyclic compounds on styrene butadiene rubber (SBR) mixes.

It has been found that the starting material 1 could react with cyromazine (2) and/or 4‐aminoantipyriene (4) as amino compounds in the presence of triethylorthoformate and in the boiling dioxane to yield triazine‐3 and/or pyrazolo 5 derivatives, respectively. The chemical structures of the new products 3 and 5 have been established by their elemental analyses spectroscopic data IR, Ms and 1H, 13C NMR. These two compounds were evaluated as antioxidants in SBR, and this evaluation was confirmed by physico‐mechanical properties of vulcanizates, IR spectra and scanning electron microscope.

The difference between maximum torque MH and minimum torque ML (ΔM), tensile strength, modulus and elongation at break increases in the presence of prepared antioxidants while the equilibrium swelling decreased. The rubber vulcanizates were subjected to thermal oxidative aging at 90°C for up to seven days. It has been found that new compounds 3 and 5 can protect SBR vulcanizates against oxidative deterioration.

The solubility of the prepared compounds 3 and 5 is very poor and they are only soluble in dimethyl formamide (DMF) or dimethyl sulphoxide (DMSO) which have high boiling points. Also, new compounds 3 and 5 have melting points (above 300°C).

Triazine and antipyrine derivatives have many medical and industrial applications.

The new synthesized compounds revealed excellent antioxidant behaviour in comparison with the commercial antioxidant phenyl‐β‐naphthyl amine (PβN) which is used in industry.