86,854 research outputs found

    Institutional Effects in a Simple Model of Educational Production

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    This paper presents a model of educational production that tries to make sense of recent evidence on effects of institutional arrangements on student performance. In a simple principal-agent framework, students choose their learning effort to maximize their net benefits, while the government chooses educational spending to maximize its net benefits. In the jointly determined equilibrium, schooling quality is shown to depend on several institutionally determined parameters. The impact on student performance of institutions such as central examinations, centralization versus school autonomy, teachers\u27 influence, parental influence, and competition from private schools is analyzed. Furthermore, the model can rationalize why positive resource effects may be lacking in educational production

    When were the Walls of Jerusalem last glaciated?

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    There is evidence to indicate that parts of the Walls of Jerusalem National Park have been glaciated on two occasions. No evidence of earlier glaciations has been found, although at least two older periods of glaciation have been demonstrated in adjacent areas. During the last glaciation, the Rowallan Glaciation, there was an incomplete ice cover and a large ice window, centred on the West Wall-Solomons Jewels area, extended from Mt Jerusalem to Howells Bluff. Rowallan-age end moraines trace the limits of this glaciation and the main erosional effects are extensive knock and lochan landscapes, The previous glaciation, the Arm Glaciation, probably covered the entire region except for the higher parts of the West Wall. The Rowallan Glaciation reached its maximum in the Mersey Valley before 13 400 ±600 years BP, Deglaciation of the upper Mersey Valley was complete before 9760 ± 720 years BP. The Arm Glaciation is likely to be older than 130 000 years

    Deep Chronnectome Learning via Full Bidirectional Long Short-Term Memory Networks for MCI Diagnosis

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    Brain functional connectivity (FC) extracted from resting-state fMRI (RS-fMRI) has become a popular approach for disease diagnosis, where discriminating subjects with mild cognitive impairment (MCI) from normal controls (NC) is still one of the most challenging problems. Dynamic functional connectivity (dFC), consisting of time-varying spatiotemporal dynamics, may characterize "chronnectome" diagnostic information for improving MCI classification. However, most of the current dFC studies are based on detecting discrete major brain status via spatial clustering, which ignores rich spatiotemporal dynamics contained in such chronnectome. We propose Deep Chronnectome Learning for exhaustively mining the comprehensive information, especially the hidden higher-level features, i.e., the dFC time series that may add critical diagnostic power for MCI classification. To this end, we devise a new Fully-connected Bidirectional Long Short-Term Memory Network (Full-BiLSTM) to effectively learn the periodic brain status changes using both past and future information for each brief time segment and then fuse them to form the final output. We have applied our method to a rigorously built large-scale multi-site database (i.e., with 164 data from NCs and 330 from MCIs, which can be further augmented by 25 folds). Our method outperforms other state-of-the-art approaches with an accuracy of 73.6% under solid cross-validations. We also made extensive comparisons among multiple variants of LSTM models. The results suggest high feasibility of our method with promising value also for other brain disorder diagnoses.Comment: The paper has been accepted by MICCAI201

    Strong solutions of the thin film equation in spherical geometry

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    We study existence and long-time behaviour of strong solutions for the thin film equation using a priori estimates in a weighted Sobolev space. This equation can be classified as a doubly degenerate fourth-order parabolic and it models coating flow on the outer surface of a sphere. It is shown that the strong solution asymptotically decays to the flat profile

    Rabies elimination research: juxtaposing optimism, pragmatism and realism

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    More than 100 years of research has now been conducted into the prevention, control and elimination of rabies with safe and highly efficacious vaccines developed for use in human and animal populations. Domestic dogs are a major reservoir for rabies, and although considerable advances have been made towards the elimination and control of canine rabies in many parts of the world, the disease continues to kill tens of thousands of people every year in Africa and Asia. Policy efforts are now being directed towards a global target of zero human deaths from dog-mediated rabies by 2030 and the global elimination of canine rabies. Here we demonstrate how research provides a cause for optimism as to the feasibility of these goals through strategies based around mass dog vaccination. We summarize some of the pragmatic insights generated from rabies epidemiology and dog ecology research that can improve the design of dog vaccination strategies in low- and middle-income countries and which should encourage implementation without further delay. We also highlight the need for realism in reaching the feasible, although technically more difficult and longer-term goal of global elimination of canine rabies. Finally, we discuss how research on rabies has broader relevance to the control and elimination of a suite of diseases of current concern to human and animal health, providing an exemplar of the value of a ‘One Health’ approach

    Synchronization Problems in Automata without Non-trivial Cycles

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    We study the computational complexity of various problems related to synchronization of weakly acyclic automata, a subclass of widely studied aperiodic automata. We provide upper and lower bounds on the length of a shortest word synchronizing a weakly acyclic automaton or, more generally, a subset of its states, and show that the problem of approximating this length is hard. We investigate the complexity of finding a synchronizing set of states of maximum size. We also show inapproximability of the problem of computing the rank of a subset of states in a binary weakly acyclic automaton and prove that several problems related to recognizing a synchronizing subset of states in such automata are NP-complete.Comment: Extended and corrected version, including arXiv:1608.00889. Conference version was published at CIAA 2017, LNCS vol. 10329, pages 188-200, 201

    Functional consequences of trust in the construction supply chain: a multi-dimensional view

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    Trust is often linked to the emergence of cooperative behaviours that contribute to successful project outcomes. However, some have questioned the functional relevance of trust in contractual relations, arguing that control-induced cooperation can emerge from enforcement of contracts. These mixed views are further complicated by the multi-dimensional nature of trust, as different trust dimensions could have varying functional consequences. The aim of this study was to provide some clarity on the functional consequence of trust in the project supply chain. Data was gathered through passive observations, document reviews and semi-structured interviews with supply chain parties on two case study projects in the UK. A thematic data analysis approach was used to uncover multiple perspectives on the functional consequences of trust in the supply chain. Findings revealed that the weaker dimensions of trust, which are impersonal (cognition-based and systems-based) and the stronger (relational-based) dimension of trust, all fostered beneficial behaviours in the supply chain (effective knowledge sharing and self-organising behaviours). However, additional behavioural consequences (relational flexibility and extra commitment) emerged when trust was relational in nature, implying that different trust dimensions and their associated behavioural consequences can be prioritized in the supply chain based on perceived work package risks

    Transition Property for α\alpha-Power Free Languages with α2\alpha\geq 2 and k3k\geq 3 Letters

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    In 1985, Restivo and Salemi presented a list of five problems concerning power free languages. Problem 44 states: Given α\alpha-power-free words uu and vv, decide whether there is a transition from uu to vv. Problem 55 states: Given α\alpha-power-free words uu and vv, find a transition word ww, if it exists. Let Σk\Sigma_k denote an alphabet with kk letters. Let Lk,αL_{k,\alpha} denote the α\alpha-power free language over the alphabet Σk\Sigma_k, where α\alpha is a rational number or a rational "number with ++". If α\alpha is a "number with ++" then suppose k3k\geq 3 and α2\alpha\geq 2. If α\alpha is "only" a number then suppose k=3k=3 and α>2\alpha>2 or k>3k>3 and α2\alpha\geq 2. We show that: If uLk,αu\in L_{k,\alpha} is a right extendable word in Lk,αL_{k,\alpha} and vLk,αv\in L_{k,\alpha} is a left extendable word in Lk,αL_{k,\alpha} then there is a (transition) word ww such that uwvLk,αuwv\in L_{k,\alpha}. We also show a construction of the word ww
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