Quotients of finite-dimensional operators by symmetry representations

A finite dimensional operator that commutes with some symmetry group admits quotient operators, which are determined by the choice of associated representation. Taking the quotient isolates the part of the spectrum supporting the chosen representation and reduces the complexity of the problem, however it is not uniquely defined. Here we present a computationally simple way of choosing a special basis for the space of intertwiners, allowing us to construct a quotient that reflects the structure of the original operator. This quotient construction generalizes previous definitions for discrete graphs, which either dealt with restricted group actions or only with the trivial representation. We also extend the method to quantum graphs, which simplifies previous constructions within this context, answers an open question regarding self-adjointness and offers alternative viewpoints in terms of a scattering approach. Applications to isospectrality are discussed, together with numerous examples and comparisons with previous results.Comment: 43 pages, 8 figure

Institutional Impediments to Groundwater Trading: the case of the Gnangara groundwater system of Western Australia

The development of a market in groundwater usage rights can be inhibited by constraints arising from the institutional context. Such impediments may reduce the potential gains from trade and may generate high transaction costs for prospective traders. We analyse the regulations and policies influencing groundwater transfers in a case-study area -- the Gnangara groundwater system around Perth, Western Australia -- and identify significant impediments to a groundwater market. Property rights are found to be conditional, temporary, and vulnerable to amendment. Regulatory approval is required for all transfers. Facilitating infrastructure is lacking, and price information is unavailable. Management area boundaries reflect land ownership and use rather than hydrogeological realities; the limitation of transfers to within these boundaries eliminates much of the potential for gains from trade. Over-allocation and weak monitoring also impede the development of a market. The current management system is likely to obscure unmet demand for water-rights transfers between users and usage-types.Agricultural and Food Policy, Environmental Economics and Policy, Institutional and Behavioral Economics, Land Economics/Use, Political Economy, Public Economics, Resource /Energy Economics and Policy, Q15, Q25, Q28, Q38, Q56, Q57, Q58, D02, R52, H41, H23, H11, D23, D47, D78, H44,

Distribution System Outage Detection using Consumer Load and Line Flow Measurements

An outage detection framework for power distribution networks is proposed. Given the tree structure of the distribution system, a method is developed combining the use of real-time power flow measurements on edges of the tree with load forecasts at the nodes of the tree. A maximum a posteriori detector {\color{black} (MAP)} is formulated for arbitrary number and location of outages on trees which is shown to have an efficient detector. A framework relying on the maximum missed detection probability is used for optimal sensor placement and is solved for tree networks. Finally, a set of case studies is considered using feeder data from the Pacific Northwest National Laboratories. We show that a 10\% loss in mean detection reliability network wide reduces the required sensor density by 60 \% for a typical feeder if efficient use of measurements is performed.Comment: Complete rework of result

International Policy and Roma Education in Europe: Essential Inputs or Centralized Distractions?

This article examines the case of Roma inclusion in education as a study of the ways in which international policy can and cannot bring change at the local level. I first reflect on the numerous international organizations and initiatives to improve the educational outcomes of Roma, and to reduce segregation and other non-inclusionary practices. Given these actions—and their relatively small impact—I identify both benefits and drawbacks of international efforts to achieve Roma inclusion and improve education outcomes. I conclude that international organizations provide significant inputs for Roma inclusion, but also serve as centralized distractions that foster extremely high expectations and thus great disappointment with the results. Cet article examine le cas de l’inclusion des Roms dans le système éducatif comme moyen d’évaluer la mesure dans laquelle la politique internationale peut effectuer des changements à l’échelle locale. Ma réflexion porte d’abord sur les nombreux organismes internationaux et les multiples initiatives qui visent l’amélioration de l’éducation aux Roms, et la réduction de la ségrégation et autres pratiques non-inclusives. Compte tenu de ces démarches—et de leur impact relativement petit—j’identifie tant les bienfaits que les désavantages des efforts internationaux qui essaient d’augmenter l’inclusion des Roms et améliorer leur éducation. Je conclus que les organismes internationaux contribuent de façon considérable à l’inclusion des Roms, mais qu’ils servent également de distractions centralisées qui favorisent des attentes extrêmement élevées et ainsi, une grande déception quant aux résultats

Growth and development of the banana plant3. A. The origin of the inflorescence and the development of the flowers: B. The structure and development of the fruit

In this paper, which is presented in two parts, the growth and development of the banana plant have been examined from the standpoint of the origin of the inflorescence and the development of the flowers (Part A) and the structure and development of the fruit (Part B). First the main centres of growth in these structures are located and the manner of their development is presented. Thereafter, attention is focused upon the salient events which determine the alternative courses of development with a view to designating the chemical and physiological stimuli that may be required

A passion for plant life

This article does not have an abstract

Precedence-type Test based on Progressively Censored Samples

In this paper, we introduce precedence-type tests for testing the hypothesis that two distribution functions are equal, which is an extension of the precedence life-test rst proposed by Nelson (1963), when the two samples are progressively Type-II censored. The null distributions of the test statistics are derived. Critical values for some combination of sample sizes and censoring schemes for the proposed tests are presented. Then, we present the exact power functions under the Lehmann alternative, and compare the exact power as well as simulated power (under location-shift) of the proposed precedence test based on nonparametric estimates of CDF with other precedence-type tests. We then examine the power properties of the proposed test procedures through Monte Carlo simulations. Two examples are presented to illustrate all the test procedures discussed here. Finally, we make some concluding remarks.Precedence test; Product-limit estimator; Type-II progressive censoring; Life-testing; level of significance; power; Lehmann alternative; Monte Carlo simulations

Zionism in a white coat: Israel’s geopolitics of medical aid development assistance of health to Africa

This article focuses on Israel’s export of medical knowledge to African states during the 1960s. Its aims are twofold. First, to evaluate and discuss the place of medical assistance and health aid within scholarship, examining the relationships between Israel and African states. Second, it will show how a discussion of Israel’s medical and health projects are linked to the regional geopolitics that shape the movement of materials, individuals and knowledge between Africa and the Middle East. By exploring the themes of security and geopolitics, positionality towards Africa, and the movement of knowledge; resources and people this paper unravel how deployment of medical aid and development assistance of health were entwined into the effort to secure Israel’s regional geopolitical objectives to position itself in proximity to different polities in Africa and interchangeably confirmed and challenged Israel’s presence in the continent. Unpacking the place of health and medical knowledge, enables a better understanding of the reciprocal relations between medical knowledge, the spaces this knowledge shapes, and the sites where it is produced