660 research outputs found
Real Time Changes in Monetary Policy
This paper investigates potential changes in monetary policy over the last decades using a nonparametric vector autoregression model. In the proposed model, the conditional mean and variance are time-dependent and estimated using a nonparametric local linear method, which allows for different forms of nonlinearity, conditional heteroskedasticity, and non-normality. Our results suggest that there have been gradual and abrupt changes in the variances of shocks, in the monetary transmission mechanism, and in the Fedās reaction function. The response of output was strongest during Volckerās disinflationary period and has since been slowly decreasing over time. There have been some abrupt changes in the response of inflation, especially in the early 1980s, but we can not conclude that it is weaker now than in previous periods. Finally, we find significant evidence that policy was passive during some parts of Burnās period, and active during Volckerās disinflationary period and Greenspanās period. However, we find that the uncovered behavior of the parameters is more complex than general conclusions suggest, since they display considerable nonlinearities over time. A particular appeal of the recursive estimation of the proposed VAR-ARCH is the detection of discrete local deviations as well as more gradual ones, without smoothing the timing or magnitude of the changes.Monetary Policy, Taylor Rule, Local Estimation, Nonlinearity, Nonparametric, Monetary Policy; Taylor Rule; Local Estimation; Nonlinearity; Nonparametric; Structural Vector Autoregression; Autoregressive Conditional Heteroskedasticity;
Coordinate actions of BMPs, Wnts, Shh and noggin mediate patterning of the dorsal somite
Shortly after their formation, somites of vertebrate embryos
differentiate along the dorsoventral axis into sclerotome,
myotome and dermomyotome. The dermomyotome is then
patterned along its mediolateral axis into medial, central
and lateral compartments, which contain progenitors of
epaxial muscle, dermis and hypaxial muscle, respectively.
Here, we used Wnt-11 as a molecular marker for the medial
compartment of dermomyotome (the āmedial lipā) to
demonstrate that BMP in the dorsal neural tube indirectly
induces formation of the medial lip by up-regulating Wnt-1
and Wnt-3a (but not Wnt-4) expression in the neural tube.
Noggin in the dorsal somite may inhibit the direct action of
BMP on this tissue. Wnt-11 induction is antagonized by
Sonic Hedgehog, secreted by the notochord and the floor
plate. Together, our results show that the coordinated
actions of the dorsal neural tube (via BMP and Wnts), the
ventral neural tube/notochord (via Shh) and the somite
itself (via noggin) mediates patterning of the dorsal compartment of the somite
Loyalists: Economic, gendered, and racial minorities acting politically for king and country.
This work will focus on the study of economic, gendered, and racial minority Loyalists in the American Revolution. The main sources include the Claims Commission Records, government documents, newspapers, diaries, letters, and autobiographies as well as secondary sources dealing with the above mentioned topics. It will specifically look at women in the colonial era. Women occupied a domestic, secondary role in the colonies and the ways that they contributed to and were affected by the war were different than their male counterparts. Previously, historians have not looked at lower ranking women and their experiences in the late eighteenth century. Also, women\u27s roles in society as contributors to and active participants in the war have not received adequate attention. This examination allows readers to understand that women were politically aware, committed, and willing to sacrifice everyday comforts for their ideologies. I will also show how women circumvented the conventions and social norms of the day to achieve their objectives. In addition to looking at the role of women in colonial society, I also look at blacksĆ¢ā¬āboth slave and freeĆ¢ā¬āwho actively aided the British during the war. Approximately thirty-five claims are available which help us understand the roles they played, sacrifices they made, and the recompense they received as a result of their loyalty. White men from the lower ranks of society are examined too, as a way to provide balance and comparison to the treatment that blacks and women received in the same era. The ultimate conclusion reached is that women and blacks were politically as well as ideologically committed and active during the American Revolution. They were aware of the ideas circulating at the time, made their decisions and actively supported loyalty. Their decision to stay within the political system of empire indicates that they made their decisions for many of the same reasons that their more elite counterparts did. It also shows the real sacrifices Loyalists made and how their lives were irrevocably changed as a result of their political alliance
Neural tube-ectoderm interactions are required for trigeminal placode formation
Cranial sensory ganglia in vertebrates develop from the ectodermal placodes, the neural crest, or both. Although much is known about the neural crest contribution to cranial ganglia, relatively little is known about how placode cells form, invaginate and migrate to their targets. Here, we identify Pax-3 as a molecular marker for placode cells that contribute to the ophthalmic branch of the trigeminal ganglion and use it, in conjunction with DiI labeling of the surface ectoderm, to analyze some of the mechanisms underlying placode development. Pax-3 expression in the ophthalmic placode is observed as early as the 4-somite stage in a narrow band of ectoderm contiguous to the midbrain neural folds. Its expression broadens to a patch of ectoderm adjacent to the midbrain and the rostral hindbrain at the 8- to 10-somite stage. Invagination of the first Pax-3-positive cells begins at the 13-somite stage. Placodal invagination continues through the 35-somite stage, by which time condensation of the trigeminal ganglion has begun. To challenge the normal tissue interactions leading to placode formation, we ablated the cranial neural crest cells or implanted barriers between the neural tube and the ectoderm. Our results demonstrate that, although the presence of neural crest cells is not mandatory for Pax-3 expression in the forming placode, a diffusible signal from the neuroectoderm is required for induction and/or maintenance of the ophthalmic placode
Measurement Error in Monetary Aggregates: A Markov Switching Factor Approach
This paper compares the different dynamics of the simple sum monetary aggregates and the Divisia monetary aggregate indexes over time, over the business cycle, and across high and low inflation and interest rate phases. Although traditional comparisons of the series sometimes suggest that simple sum and Divisia monetary aggregates share similar dynamics, there are important differences during certain periods, such as around turning points. These differences cannot be evaluated by their average behavior. We use a factor model with regime switching. The model separates out the common movements underlying the monetary aggregate indexes, summarized in the dynamic factor, from individual variations in each individual series, captured by the idiosyncratic terms. The idiosyncratic terms and the measurement errors reveal where the monetary indexes differ. We find several new results. In general, the idiosyncratic terms for both the simple sum aggregates and the Divisia indexes display a business cycle pattern, especially since 1980. They generally rise around the end of high interest rate phases ā a couple of quarters before the beginning of recessions ā and fall during recessions to subsequently converge to their average in the beginning of expansions. We find that the major differences between the simple sum aggregates and Divisia indexes occur around the beginnings and ends of economic recessions, and during some high interest rate phases. We note the inferencesā policy relevance, which is particularly dramatic at the broadest (M3) level of aggregation. Indeed, as Belongia (1996) has observed in this regard, āmeasurement matters.āMeasurement Error, Divisia Index, Aggregation, State Space, Markov Switching, Monetary Policy
Measurement Error in Monetary Aggregates: A Markov Switching Factor Approach
This paper compares the different dynamics of simple sum monetary aggregates and the Divisia indexes over time, over the business cycle, and across high and low inflation and interest rate phases. Although the traditional comparison of the series may suggest that they share similar dynamics, there are important differences during certain times and around turning points that can not be evaluated by their average behavior. We use a factor model with regime switching that offers several ways in which these differences can be analyzed. The model separates out the common movements underlying the monetary aggregate indexes, summarized in the dynamic factor, from individual variations in each one series, captured by the idiosyncratic terms. The idiosyncratic terms and the measurement errors represent exactly where the monetary indexes differ. We find several new results. In general, the idiosyncratic terms for both the simple sum aggregates and the Divisia indexes display a business cycle pattern, especially since 1980. They generally rise around the end of high interest rate phases ā a couple of quarters before the beginning of recessions ā and fall during recessions to subsequently converge to their average in the beginning of expansions. We also find that the major differences between the simple sum aggregates and Divisia indexes occur around the beginning and end of economic recessions, and during some high interest rate phases.Measurement Error, Divisia Index, Aggregation, State Space, Markov Switching, Monetary Policy
Measurement Error in Monetary Aggregates: A Markov Switching Factor Approach
This paper compares the different dynamics of the simple sum monetary aggregates and the Divisia monetary aggregate indexes over time, over the business cycle, and across high and low inflation and interest rate phases. Although traditional comparisons of the series sometimes suggest that simple sum and Divisia monetary aggregates share similar dynamics, there are important differences during certain periods, such as around turning points. These differences cannot be evaluated by their average behavior. We use a factor model with regime switching. The model separates out the common movements underlying the monetary aggregate indexes, summarized in the dynamic factor, from individual variations in each individual series, captured by the idiosyncratic terms. The idiosyncratic terms and the measurement errors reveal where the monetary indexes differ. We find several new results. In general, the idiosyncratic terms for both the simple sum aggregates and the Divisia indexes display a business cycle pattern, especially since 1980. They generally rise around the end of high interest rate phases ā a couple of quarters before the beginning of recessions ā and fall during recessions to subsequently converge to their average in the beginning of expansions. We find that the major differences between the simple sum aggregates and Divisia indexes occur around the beginnings and ends of economic recessions, and during some high interest rate phases. We note the policy relevance of the inferences. Indeed, as Belongia (1996) has observed in this regard, "measurement matters."Measurement error; monetary aggregation; Divisia index; aggregation; state space; Markov switching; monetary policy; index number theory; factor models
Measurement Error in Monetary Aggregates: A Markov Switching Factor Approach
This paper compares the different dynamics of the simple sum monetary aggregates and the Divisia monetary aggregate indexes over time, over the business cycle, and across high and low inflation and interest rate phases. Although traditional comparisons of the series sometimes suggest that simple sum and Divisia monetary aggregates share similar dynamics, there are important differences during certain periods, such as around turning points. These differences cannot be evaluated by their average behavior. We use a factor model with regime switching. The model separates out the common movements underlying the monetary aggregate indexes, summarized in the dynamic factor, from individual variations in each individual series, captured by the idiosyncratic terms. The idiosyncratic terms and the measurement errors reveal where the monetary indexes differ. We find several new results. In general, the idiosyncratic terms for both the simple sum aggregates and the Divisia indexes display a business cycle pattern, especially since 1980. They generally rise around the end of high interest rate phases ā a couple of quarters before the beginning of recessions ā and fall during recessions to subsequently converge to their average in the beginning of expansions. We find that the major differences between the simple sum aggregates and Divisia indexes occur around the beginnings and ends of economic recessions, and during some high interest rate phases. We note the inferencesā policy relevance, which is particularly dramatic at the broadest (M3) level of aggregation. Indeed, as Belongia (1996) has observed in this regard, āmeasurement matters.āMeasurement Error, Divisia Index, Aggregation, State Space, Markov Switching, Monetary Policy
Competence, specification and induction of Pax-3 in the trigeminal placode
Placodes are discrete regions of thickened ectoderm that contribute extensively to the peripheral nervous system in the vertebrate head. The paired-domain transcription factor Pax-3 is an early molecular marker for the avian ophthalmic trigeminal (opV) placode, which forms sensory neurons in the ophthalmic lobe of the trigeminal ganglion. Here, we use collagen gel cultures and heterotopic quail-chick grafts to examine the competence, specification and induction of Pax-3 in the opV placode. At the 3-somite stage, the whole head ectoderm rostral to the first somite is competent to express Pax-3 when grafted to the opV placode region, though competence is rapidly lost thereafter in otic-level ectoderm. Pax-3 specification in presumptive opV placode ectoderm occurs by the 8-somite stage, concomitant with robust Pax-3 expression. From the 8-somite stage onwards, significant numbers of cells are committed to express Pax-3. The entire length of the neural tube has the ability to induce Pax-3 expression in competent head ectoderm and the inductive interaction is direct. We propose a detailed model for Pax-3 induction in the opV placode
Measurement Error in Monetary Aggregates:Ā A Markov Switching Factor Approach
This is the author's final draft of an article for which the publisher's official version is available electronically from: http://dx.doi.org/10.1017/S1365100509090166This paper compares the different dynamics of the simple-sum monetary aggregates and the Divisia monetary aggregate indices over time, over the business cycle, and across high and low inflation and interest-rate phases. Although traditional comparisons of the series sometimes suggest that simple-sum and Divisia monetary aggregates share similar dynamics, there are important differences around turning points that cannot be evaluated by their average behavior. We use a factor model with a regime-switching model that separates the common movements underlying the monetary aggregate indices from idiosyncratic variations in each series. We find that the major differences between the simple-sum aggregates and Divisia indices occur around the beginnings and ends of recessions and during some high-interest-rate phases. We note the inferences' policy relevance, which is particularly dramatic at the broadest (M3) level of aggregation. Indeed, as Belongia [Journal of Political Economy, 104 (5) (1996), 1065ā1083] has observed in this regard, āmeasurement matters.
- ā¦