1,187 research outputs found
Betting on Death and Capital Markets in Retirement: A Shortfall Risk Analysis of Life Annuities versus Phased Withdrawal Plans
How might retirees consider deploying the retirement assets accumulated in a defined contribution pension plan? One possibility would be to purchase an immediate annuity. Another approach, called the “phased withdrawal” strategy in the literature, would have the retiree invest his funds and then withdraw some portion of the account annually. Using this second tactic, the withdrawal rate might be determined according to a fixed benefit level payable until the retiree dies or the funds run out, or it could be set using a variable formula, where the retiree withdraws funds according to a rule linked to life expectancy. Using a range of data consistent with the German experience, we evaluate several alternative designs for phased withdrawal strategies, allowing for endogenous asset allocation patterns, and also allowing the worker to make decisions both about when to retire and when to switch to an annuity. We show that one particular phased withdrawal rule is appealing since it offers relatively low expected shortfall risk, good expected payouts for the retiree during his life, and some bequest potential for the heirs. We also find that unisex mortality tables if used for annuity pricing can make women’s expected shortfalls higher, expected benefits higher, and bequests lower under a phased withdrawal program. Finally, we show that delayed annuitization can be appealing since it provides higher expected benefits with lower expected shortfalls, at the cost of somewhat lower anticipated bequests.
Doping-induced quantum cross-over in ErTiSnO
We present the results of the investigation of magnetic properties of the
ErTiSnO series. For small doping values the ordering
temperature decreases linearly with while the moment configuration remains
the same as in the parent compound. Around doping level we
observe a change in the behavior, where the ordering temperature starts to
increase and new magnetic Bragg peaks appear. For the first time we present
evidence of a long-range order (LRO) in ErSnO () below
mK. It is revealed that the moment configuration corresponds to a
Palmer-Chalker type with a value of the magnetic moment significantly
renormalized compared to . We discuss our results in the framework of a
possible quantum phase transition occurring close to .Comment: accepted in PRB Rapi
TeV-scale Seesaw with Quintuplet Fermions
We propose a new seesaw model based on fermionic hypercharge zero weak
quintuplet in conjunction with additional scalar quadruplet which attains an
induced vev. The model provides both tree-level seesaw ~ v^6/M^5 and a
loop-suppressed radiative ~ (1 / 16 \pi^2) v^2/M contributions to active
neutrino masses. The empirical masses m_\nu ~ 10^{-1} eV can be achieved with M
~ TeV new states, accessible at the LHC. For 5 fb^{-1} of accumulated
integrated luminosity at the LHC, there could be ~ 500 doubly-charged
\Sigma^{++} or \bar{\Sigma^{++}} fermions with mass M_\Sigma = 400 GeV, leading
to interesting multi-lepton signatures. The neutral component of the fermion
quintuplet, previously identified as minimal dark matter candidate, becomes
unstable in the proposed seesaw setup. The stability can be restored by
introducing a Z_2 symmetry, in which case neutrinos get mass only from
radiative contributions.Comment: 19 pages, 9 figures, corresponds to published versio
Optimizing the Retirement Portfolio: Asset Allocation, Annuitization, and Risk Aversion
Retirees must draw down their accumulated assets in an orderly fashion so as not to exhaust their funds too soon. We derive the optimal retirement portfolio from a menu that includes payout annuities as well as an investment allocation and a withdrawal strategy, assuming risk aversion, stochastic capital markets, and uncertain lifetimes. The resulting portfolio allocation, when fixed as of retirement, is then compared to phased withdrawal strategies such a %u201Cself-annuitization%u201D plan or the 401(k) %u201Cdefault%u201D pattern encouraged under US tax law. Surprisingly, the fixed percentage approach proves appealing for retirees across a wide range of risk preferences, supporting financial planning advisors who often recommend this rule. We then permit the retiree to switch to an annuity later, which gives her the chance to invest in the capital market and %u201Cbet on death.%u201D As risk aversion rises, annuities first crowd out bonds in retiree portfolios; at higher risk aversion still, annuities replace equities in the portfolio. Making annuitization compulsory can also lead to substantial utility losses for less risk-averse investors.
Spectroscopy of the stellar wind in the Cygnus X-1 system
The X-ray luminosity of black holes is produced through the accretion of
material from their companion stars. Depending on the mass of the donor star,
accretion of the material falling onto the black hole through the inner
Lagrange point of the system or accretion by the strong stellar wind can occur.
Cygnus X-1 is a high mass X-ray binary system, where the black hole is powered
by accretion of the stellar wind of its supergiant companion star HDE226868. As
the companion is close to filling its Roche lobe, the wind is not symmetric,
but strongly focused towards the black hole. Chandra-HETGS observations allow
for an investigation of this focused stellar wind, which is essential to
understand the physics of the accretion flow. We compare observations at the
distinct orbital phases of 0.0, 0.2, 0.5 and 0.75. These correspond to
different lines of sights towards the source, allowing us to probe the
structure and the dynamics of the wind.Comment: conference proceeding from Integral/Bart Workshop Karlsbad, CZ,
14.4-18.4 201
Stalk rot resistance in Maksimir 3 synthetic maize population after four cycles of recurrent selection
Fusarium stalk rot (FSR) and anthracnose stalk rot (ASR), caused by Fusarium
spp. and Colletotrichum graminicola (Ces.) G.W. Wils. respectively, are the
two most important stalk diseases in maize which increase the incidence of
stalk lodging and reduce grain yield. The aim of the present study was to (1)
evaluate the effect of four cycles of recurrent selection in the Maksimir 3
Synthetic (M3S) maize population on ASR and FSR resistance and (2) to
investigate the correlation among the different disease rating methods. The
experiment included six M3S cycle populations per se and their test-crosses
with a single cross hybrid. ASR resistance was estimated on artificially
inoculated plant rows using three ratings (the number of infected internodes,
the number of internodes rotten more than 75% and evaluation of outer stalk
discoloration) whereas FSR resistance was estimated in artificially
inoculated rows as well as in naturally inoculated rows by rating severity of
disease symptoms on longitudinally cut stalks using the standard resistance
scale. The results of the present study showed that four cycles of selection
in the M3S maize population, conducted primarily for grain yield improvement,
did not significantly affect its resistance to both ASR and FSR. Among the
disease ratings a moderate positive correlation was found only between two
ASR resistance ratings (the number of infected internodes and the number of
internodes rotted more than 75%) in both population per se (r=0.49**) and
population test-crosses (r=0.56**)
Superconducting properties of an Ag-CLAD (BiPb)_2Sr_2Ca_2Cu_3O_10+y tape
AC susceptibility and V-I characteristics of a well characterised Ag-clad Bi-Pb-Sr-Ca-Cu-O tape have been studied in the temperature (T) range 77-106 K and magnetic fields (B) up to 0.06 T. The intrinsic critical current density J_s (from ac susceptibility) is 30000 A/cm2 at 77 K whereas the transport critical current density Jc (from V-I curves) is 10100 A/cm2 at the same temperature. Both Js and Jc showed power law variations with T and B, respectively, characteristic for intragranular flux creep. From the dissipation within the core the differential resistance Rf (associated with the flux flow) has been deduced. The magnitude and the variations of Rf with T and B are consistent with those due to flux flow in type II superconductors in low field. From d^2 V/d I^2 vs I curves very broad critical current distribution CCD has been deduced
Distribution and forms of iron in the vertisols of Serbia
Soil of arable land and meadows from the Ap horizon, taken from ten different localities, were investigated for different forms of Fe, including total (HF), pseudo-total (HNO3), 0.1 M HCl extractable and DTPA (diethylenetriaminepentaacetic acid)-extractable. A sequential fractional procedure was employed to separate the Fe into fractions: water soluble and exchangeable Fe (I), Fe specifically adsorbed with carbonates (II), reducibly releasable Fe in oxides (III), Fe bonded with organic matter (IV) and Fe structurally bonded in silicates (residual fraction) (V). The soil pH, cation exchange capacity, and size fractions (clay and silt) had a strongest influence on the distribution of the different forms of Fe. The different extraction methods showed similar patterns of the Fe content in arable and meadow soils. However, the DTPA iron did not correspond with the total iron, which confirms the widespread incidence of iron-deficiency in vertisols is independent of the total iron in soils. The amount of exchangeable (fraction I) and specifically adsorbed (II) iron showed no dependence on its content in the other fractions, indicating low mobility of iron in vertisols. The strong positive correlation (r = 0.812 and 0.956) between the content of iron in HNO3 and HF and its contents in the primary and secondary minerals (fraction – V) indicate a low content of plant accessible iron in the vertisol. The sequential fractional procedure was confirmed as suitable for accessing the content and availability of iron in the vertisols of Serbia
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