170 research outputs found

    Money Stock Targeting, Base Drift and Price-Level Predictability: Lessons From the U.K. Experience

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    It is controversial whether money stock targeting without base drift (i.e. following a trend-stationary growth path) makes the price level more predictable in the presence of permanent shocks to money demand. Developing a procedure that does not run into the Lucas critique, and applying this procedure to the case of the U.K., the paper finds that the variance of the trend inflation rate in the U.K. would have been reduced by more than one half if the Bank of England had not allowed base drift.

    Was Expansionary Monetary Policy Feasible During the Great Contraction? An Examination of the Gold Standard Constraint

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    The recent consensus view, that the gold standard was the leading cause of the worldwide Great Depression 1929-33, stems from two propositions: (1) Under the gold standard, deflationary shocks were transmitted between countries and, (2) for most countries, continued adherence to gold prevented monetary authorities from offsetting banking panics and blocked their recoveries. In this paper we contend that the second proposition applies only to small open economies with limited gold reserves. This was not the case for the US, the largest country in the world, holding massive gold reserves. The US was not constrained from using expansionary policy to offset banking panics, deflation, and declining economic activity. Simulations, based on a model of a large open economy, indicate that expansionary open market operations by the Federal Reserve at two critical junctures (October 1930 to February 1931; September 1931 through January 1932) would have been successful in averting the banking panics that occurred, without endangering convertibility. Indeed had expansionary open market purchases been conducted in 1930, the contraction would not have led to the international crises that followed.

    Money Growth Variability and Money Supply Interdependence Under InterestRate Control: Some Evidence For Canada

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    Canada, like many countries, has recently experienced difficulties in achieving money growth stability and money supply independence. Based on the buffer-stock view of money-holding as well as the credit market approach to the money supply, this paper suggests that the problems have arisen from the Bank of Canada suse of an interestrate control mechanism.The paper argues that: (1) The short-run behavior of Canadian money grow this influenced by demand shifts in the Canadian credit market.(2)Movements in U.S. interest rates relative to the controlled Canadian interest rates are a key source of these shifts.The paper presents evidence on Canadian money supply and demand functions consistent with the foregoing explanation.

    Real-time recognition of sows in video : A supervised approach

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    This paper proposes a supervised classification approach for the real-time pattern recognition of sows in an animal supervision system (asup). Our approach offers the possibility of the foreground subtraction in an asup’s image processing module where there is lack of statistical information regarding the background. A set of 7 farrowing sessions of sows, during day and night, have been captured (approximately 7 days/sow), which is used for this study. The frames of these recordings have been grabbed with a time shift of 20 second. A collection of 215 frames of 7 different sows with the same lighting condition have been marked and used as the training set. Based on small neighborhoods around a point, a number of image local features are defined, and their separability and performance metrics are compared. For the classification task, a feed-forward neural network (NN) is studied and a realistic configuration in terms of an acceptable level of accuracy and computation time is chosen. The results show that the dense neighborhood feature (d.3x3) is the smallest local set of features with an acceptable level of separability, while it has no negative effect on the complexity of NN. The results also confirm that a significant amount of the desired pattern is accurately detected, even in situations where a portion of the body of a sow is covered by the crate’s elements. The performance of the proposed feature set coupled with our chosen configuration reached the rate of 8.5 fps. The true positive rate (TPR) of the classifier is 84.6%, while the false negative rate (FNR) is only about 3%. A comparison between linear logistic regression and NN shows the highly non-linear nature of our proposed set of features.Peer reviewe

    Expression variations in ectodysplasin-A gene (eda) may contribute to morphological divergence of scales in haplochromine cichlids

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    Background Elasmoid scales are one of the most common dermal appendages and can be found in almost all species of bony fish differing greatly in their shape. Whilst the genetic underpinnings behind elasmoid scale development have been investigated, not much is known about the mechanisms involved in moulding of scales. To investigate the links between gene expression differences and morphological divergence, we inferred shape variation of scales from two different areas of the body (anterior and posterior) stemming from ten haplochromine cichlid species from different origins (Lake Tanganyika, Lake Malawi, Lake Victoria and riverine). Additionally, we investigated transcriptional differences of a set of genes known to be involved in scale development and morphogenesis in fish. Results We found that scales from the anterior and posterior part of the body strongly differ in their overall shape, and a separate look on scales from each body part revealed similar trajectories of shape differences considering the lake origin of single investigated species. Above all, nine as well as 11 out of 16 target genes showed expression differences between the lakes for the anterior and posterior dataset, respectively. Whereas in posterior scales four genes (dlx5, eda, rankl and shh) revealed significant correlations between expression and morphological differentiation, in anterior scales only one gene (eda) showed such a correlation. Furthermore, eda displayed the most significant expression difference between species of Lake Tanganyika and species of the other two younger lakes. Finally, we found genetic differences in downstream regions of eda gene (e.g., in the eda-tnfsf13b inter-genic region) that are associated with observed expression differences. This is reminiscent of a genetic difference in the eda-tnfsf13b inter-genic region which leads to gain or loss of armour plates in stickleback. Conclusion These findings provide evidence for cross-species transcriptional differences of an important morphogenetic factor, eda, which is involved in formation of ectodermal appendages. These expression differences appeared to be associated with morphological differences observed in the scales of haplochromine cichlids indicating potential role of eda mediated signal in divergent scale morphogenesis in fish.Peer reviewe

    Transcriptomics unravels molecular players shaping dorsal lip hypertrophy in the vacuum cleaner cichlid, Gnathochromis permaxillaris

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    BackgroundTeleosts display a spectacular diversity of craniofacial adaptations that often mediates ecological specializations. A considerable amount of research has revealed molecular players underlying skeletal craniofacial morphologies, but less is known about soft craniofacial phenotypes. Here we focus on an example of lip hypertrophy in the benthivorous Lake Tangnayika cichlid, Gnathochromis permaxillaris, considered to be a morphological adaptation to extract invertebrates out of the uppermost layer of mud bottom. We investigate the molecular and regulatory basis of lip hypertrophy in G. permaxillaris using a comparative transcriptomic approach.ResultsWe identified a gene regulatory network involved in tissue overgrowth and cellular hypertrophy, potentially associated with the formation of a locally restricted hypertrophic lip in a teleost fish species. Of particular interest were the increased expression level of apoda and fhl2, as well as reduced expression of cyp1a, gimap8, lama5 and rasal3, in the hypertrophic lip region which have been implicated in lip formation in other vertebrates. Among the predicted upstream transcription factors, we found reduced expression of foxp1 in the hypertrophic lip region, which is known to act as repressor of cell growth and proliferation, and its function has been associated with hypertrophy of upper lip in human.ConclusionOur results provide a genetic foundation for future studies of molecular players shaping soft and exaggerated, but locally restricted, craniofacial morphological changes in fish and perhaps across vertebrates. In the future, we advocate integrating gene regulatory networks of various craniofacial phenotypes to understand how they collectively govern trophic and behavioural adaptations.Peer reviewe

    A Closer Look at Few-Shot Crosslingual Transfer: The Choice of Shots Matters

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    Few-shot crosslingual transfer has been shown to outperform its zero-shot counterpart with pretrained encoders like multilingual BERT. Despite its growing popularity, little to no attention has been paid to standardizing and analyzing the design of few-shot experiments. In this work, we highlight a fundamental risk posed by this shortcoming, illustrating that the model exhibits a high degree of sensitivity to the selection of few shots. We conduct a large-scale experimental study on 40 sets of sampled few shots for six diverse NLP tasks across up to 40 languages. We provide an analysis of success and failure cases of few-shot transfer, which highlights the role of lexical features. Additionally, we show that a straightforward full model finetuning approach is quite effective for few-shot transfer, outperforming several state-of-the-art few-shot approaches. As a step towards standardizing few-shot crosslingual experimental designs, we make our sampled few shots publicly available

    Could Stable Money Have Averted The Great Contraction?

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    We test the hypothesis that the Great Contraction would have been attenuated had the Fed not allowed the money stock to decline. We do so by simulating a model that estimates separate relations for output and the price level and assumes that output and price dynamics are not especially sensitive to policy changes. The simulations include a strong and a weak form of Friedman's constant money growth rule. The results support the hypothesis that the Great Contraction would have been mitigated and shortened had the Fed followed a constant money growth rule.
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