112 research outputs found
Stock returns and inflation : The role of the monetary sector
This paper hypothesizes that the relation between stock returns and inflation is caused by the equilibrium process in the monetary sector. More importantly, these relations vary over time in a systematic manner depending on the influence of money demand and supply factors. Post-war evidence from the United States, Canada, the United Kingdom and Germany indicates that the negative stock return-inflation relations are caused by money demand and counter-cyclical money supply effects. On the other hand, pro-cyclical movements in money, inflation, and stock prices during the 1930's lead to relations which are either positive or insignificant.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26693/1/0000240.pd
Components of short-horizon individual security returns
In this paper, we present a simple model which relates security returns to three components: an expected return, a bid-ask error, and white noise. The relative importance of the various components is empirically assessed, and the model's ability to explain the various time-series properties of individual security and portfolio returns is tested. Time-varying expected returns and bid-ask errors are found to explain substantial proportions (up to 24%) of the variance of security returns. We also reconcile the typically negative autocorrelation in security returns with the strong positive autocorrelation in portfolio returns.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29106/1/0000144.pd
Spin-state driven ferromagnetic and spin glass states in layered LaSrCoO
Famous for its spin-state puzzle, LaSrCoO (Co) is an intermediate
between antiferromagnetic (AFM) LaCoO (Co) and ferromagnetic
(FM) SrCoO (Co). The appearance of the Co valence state
(not present in the end compounds) is intriguing because of the spin-state
transitions associated with it. In this work, we report two magnetic
transitions in LaSrCoO: (i) a transition at T T 225 K,
from the paramagnetic state to a state with an inhomogeneous long-range
ferromagnetic (FM) order wherein finite FM clusters coexist with infinite FM
matrix in the percolation sense, and (ii) the transition to the cluster spin
glass (CSG) state at T T 8 K. Finite FM clusters (which at low
temperatures give rise to the cluster spin glass state) and infinite FM matrix
are formed due to the spin-spin interactions brought about by the
inhomogeneously distributed Co high spin (HS) and Co low spin
(LS) ions. A firm support to the presence of an unconventional (inhomogeneous)
ferromagnetic order comes from the anomalous values of the critical exponents
, and for the spontaneous magnetization, `zero-field'
magnetic susceptibility and the critical M - H isotherm, while the coexistence
of HS Co and LS Co ions is confirmed by the results of the
extended X-ray absorption fine structure spectroscopy.Comment: 18 pages, 6 figure
Information, trading, and volatility
We examine the effects of trading and information flows on the short-run behavior of stock prices by comparing the behavior of stock return volatility during trading and nontrading periods. We define nontrading periods as periods when exchanges and businesses are open but traders endogenously choose not to trade. After correcting for the bid/ask bounce and stickiness in quotes, we find that a large proportion of daily stock return volatility occurs without trades, especially for large firms. Furthermore, we provide new evidence that public (versus private) information is the major source of short-term return volatility.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31397/1/0000312.pd
Electroweak Symmetry Breaking and BSM Physics (A Review)
In this talk, I shall first discuss the standard model Higgs mechanism and
then highlight some of its deficiencies making a case for the need to go beyond
the standard model (BSM). The BSM tour will be guided by symmetry arguments. I
shall pick up four specific BSM scenarios, namely, supersymmetry, Little Higgs,
Gauge-Higgs unification, and the Higgsless approach. The discussion will be
confined mainly on their electroweak symmetry breaking aspects.Comment: 17 pages, 10 eps figs, Based on plenary talks at the International
Conferences: WIN07, Kolkata, Jan'07, and WHEPP-10, Chennai, Jan'08. To appear
in the WHEPP-10 proceedings (a special issue of PRAMANA
A Pedagogical Review of Electroweak Symmetry Breaking Scenarios
We review different avenues of electroweak symmetry breaking explored over
the years. This constitutes a timely exercise as the world's largest and the
highest energy particle accelerator, namely, the Large Hadron Collider (LHC) at
CERN near Geneva, has started running whose primary mission is to find the
Higgs or some phenomena that mimic the effects of the Higgs, i.e. to unravel
the mysteries of electroweak phase transition. In the beginning, we discuss the
Standard Model Higgs mechanism. After that we review the Higgs sector of the
Minimal Supersymmetric Standard Model. Then we take up three relatively recent
ideas: Little Higgs, Gauge-Higgs Unification, and Higgsless scenarios. For the
latter three cases, we first present the basic ideas and restrict our
illustration to some instructive toy models to provide an intuitive feel of the
underlying dynamics, and then discuss, for each of the three cases, how more
realistic scenarios are constructed and how to decipher their experimental
signatures. Wherever possible, we provide enough pedagogical details, which the
beginners might find useful.Comment: 45 pages, Review based on a series of lectures; v2: 63 pages,
substantially expanded, references added, to appear in `Reports on Progress
in Physics
Antibodies against a Surface Protein of Streptococcus pyogenes Promote a Pathological Inflammatory Response
Streptococcal toxic shock syndrome (STSS) caused by Streptococcus pyogenes is a clinical condition with a high mortality rate despite modern intensive care. A key feature of STSS is excessive plasma leakage leading to hypovolemic hypotension, disturbed microcirculation and multiorgan failure. Previous work has identified a virulence mechanism in STSS where M1 protein of S. pyogenes forms complexes with fibrinogen that activate neutrophils to release heparin-binding protein (HBP), an inducer of vascular leakage. Here, we report a marked inter-individual difference in the response to M1 protein–induced HBP release, a difference found to be related to IgG antibodies directed against the central region of the M1 protein. To elicit massive HBP release, such antibodies need to be part of the M1 protein–fibrinogen complexes. The data add a novel aspect to bacterial pathogenesis where antibodies contribute to the severity of disease by promoting a pathologic inflammatory response
The 'Fed Model' and the Changing Correlation of Stock and Bond Returns: An Equilibrium Approach
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