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.

The Conditions of Primary Infection Define the Load of Latent Viral Genome in Organs and the Risk of Recurrent Cytomegalovirus Disease

Recurrence of cytomegalovirus (CMV) from latency is a frequent cause of disease in immunocompromised patients. To date, there is no explanation for the diversity in the clinical manifestations. Primary infection can occur perinatally or later in life, and inevitably results in latent infection. Seropositivity for antibodies against CMV is indicative of latent infection, but is insufficient as a predictor for the risk of recurrence. As a model for this important medical problem, we compared the risks of murine CMV recurrence from latency established after neonatal primary infection and after infection at adult age. The risk of CMV recurrence was high only after neonatal infection. The copy number of latent viral genome in tissues was identified as the key parameter that determines the overall and organ-specific risks of recurrence. Latent CMV burden and risk of recurrence were related to the extent of virus multiplication during primary infection. The presence of latent CMV in multiple organs provides the molecular basis for stochastic events of recurrence in single organs or in any combination thereof. These findings are discussed as a concept of multifocal CMV latency and recurrence. It provides a rationale for the diversity in the clinical outcome of CMV disease

Acidic pH reduces agonist efficacy and responses to synaptic-like glycine applications in zebrafish α1 and rat α1β recombinant glycine receptors

Many pentameric ligand-gated ion channels are modulated by extracellular pH. Glycine receptors (GlyRs) share this property, but it is not well understood how they are affected by pH changes. Whole cell experiments on HEK293 cells expressing zebrafish homomeric α1 GlyR confirmed previous reports that acidic pH (6.4) reduces GlyR sensitivity to glycine, whereas alkaline pH (8.4) has small or negligible effects. In addition to that, at pH 6.4 we observed a reduction in the maximum responses to the partial agonists β-alanine and taurine relative to the full agonist glycine. In cell-attached single-channel recording, low pH reduced agonist efficacy, as the maximum open probability decreased from 0.97, 0.91 and 0.66 to 0.93, 0.57 and 0.34 for glycine, β-alanine and taurine, respectively, reflecting a threefold decrease in efficacy equilibrium constants for all three agonists. We also tested the effect of pH 6.4 in conditions that replicate those at the native synapse, recording outside-out currents elicited by fast application of millisecond pulses of agonists on α1 and α1β GlyR, at a range of intracellular chloride concentrations. Acidic pH reduced the area under the curve of the currents, by reducing peak amplitude, slowing activation and speeding deactivation. Our results show that acidification of the extracellular pH by one unit, as may occur in pathological conditions such as ischaemia, impairs GlyR gating and is likely to reduce the effectiveness of glycinergic synaptic inhibition

Growth and Gonad Changes in Stony Sea Urchin, Paracentrotus Lividus (Lamark, 1816) Fed Artificially Formulated Feed and Benthic Macrophyte Diet

This study reported the efficiency of artificially formulated feed and benthic macrophyte diet on growth and gonad development of cultured stony sea urchin, Paracentrotus lividus (Lamark, 1816). An initial sample of 720 individual urchins was gathered in coastal area of SE Adriatic, near Dubrovnik, Croatia and for the purposes of the experiment, was held in a flow-through system. Sea urchin were fed four test diets A, B, C and D. Diet A consisted of seaweeds collected in the natural habitat of sampled sea urchin, artificial diets B, C, and D contained a different ratio of ingredients. The feed mixtures differed in respect to corn meal content; B (22%), C (30%) and D (35%) as well as the distribution of fish meal content; B (15%), C (5%) and D (0%). Prior to the commencement of feeding, sea urchins in all groups were starved for 15 days. During the period of starvation, recorded total urchin weight, gonadosomatic index (GSI) and gonad weight values for all experimental groups, showed a declining trend except in the control group, where they stayed the same. After 30 days, the declining trend of morphometric values was recorded for treatment A and the control group. During the two months of the intensive feeding conditions in the regimes with artificially prepared feed, B, C and D a growing trend was recorded for all morphometric values, and it was particularly evident in the treatment C. In the last month of the experiment, a significant decline in the GSI and gonad weight values were observed for the groups, A and the control. The differences among the artificially formulated feeds expressed through increase of GSI and gonad mass values revealed that the best among them was artificial feed C whose variance in consistence of essential nutritional components fits between prepared feeds B and D. Based on the results of our study we conclude that the artificially formulated feed is adequate food for sea urchins in a controlled environment, especially when it contains a smaller animal protein component (5- 10%) and a larger share of plant components (over 90%)

Poništenje teško-lakih fermionskih vezanih stanja dvofotonskim raspadom

We consider the double-radiative decays of heavy-light QED and QCD atoms, µ+e− → γγ and B¯0 s → γγ. Especially, we take under scrutiny contributions coming from operators that vanish on the free-quark mass shell. We show that by field redefinitions, these operators are converted into contact terms attached to the bound state dynamics. A net off-shell contribution is suppressed with respect to the effect of the well known flavour-changing magnetic-moment operator by the bound-state binding factor. The negligible off-shellness of the weakly-bound QED atoms becomes more relevant for strongly bound QCD atoms. We analyse this off-shellness in model-approaches to QCD, one of them enabling us to keep close contact to the related effect in QED. We also comment on the off-shell effect in the corresponding process B¯d → K∗γ, and discuss possible hindering of the claimed beyond-standardmodel discovery in this decay mode.Razmatramo dvofotonske raspade teško-lakih atoma kvantne elektrodinamike i kromodinamike (QED i QCD), µ+e− → γγ i B¯0 s → γγ. Posebice, istražujemo doprinose operatora koji trnu na ljusci mase slobodnih kvarkova. Pokazujemo da se redefinicijom polja ovi operatori pretvaraju u kontaktne članove povezane s dinamikom vezanih stanja. Ukupan doprinos izvan ljuske mase je potisnut u odnosu na učinak dobro poznatog operatora magnetskog momenta zbog faktora vezanja vezanog stanja. Učinci izvan ljuske u slabo vezanim QED atomima su zanemarivi, međutim, oni postaju znatni u jako vezanim QCD atomima. Analiziramo te učinke izvan ljuske u modelskim pristupima QCD, od kojih nam jedan omogućuje blisku usporedbu s odnosnim učinkom u QED. Također navodimo učinak izvan ljuske u srodnom procesu B¯d → K∗γ, kao prepreku za razotkrivanje najavljenih mogućih učinaka fizike izvan standardnog modela

Procjena fizičkog opterećenja statističkom analizom srčane frekvencije u radnice na vrpci u punionici pića

Physical work load was estimated in a female conveyor-belt worker in a bottling plant. Estimation was based on continuous measurement and on calculation of average heart rate values in three-minute and one-hour periods and during the total measuring period. The thermal component of the heart rate was calculated by means of the corrected effective temperature, for the one-hour periods. The average heart rate at rest was also determined. The work component of the heart rate was calculated by subtraction of the resting heart rate and the heart rate measured at 50 W, using a regression equation. The average estimated gross energy expenditure during the work was 9.6±1.3 kJ/min corresponding to the category of light industrial work. The average estimated oxygen uptake was 0.42±0.06 L/min. The average performed mechanical work was 12.2±4.2 W, i.e. the energy expenditure was 8.3±1.5%.U radu je prikazan način procjene fizičkog opterećenja u radnice na vrpci u punionici pića, temeljene na kontinuiranom mjerenju i izračunavanju prosječnih vrijednosti srčane frekvencije u trominutnim i jednosatnim razdobljima, te tijekom čitavog razdoblja mjerenja. Regresijskom jednadžbom koja koristi vrijednost korigirane efektivne temperature, izračunane iz parametara mikroklime mjerenih u jednosatnim razdobljima, izračunata je toplinska sastavnica srčane frekvencije. Tijekom mirovanja također je određena prosječna vrijednost srčane frekvencije. Oduzimanjem srčane frekvencije u mirovanju i toplinske sastavnice srčane frekvencije od aktualne srčane frekvencije, dobivena je radna sastavnica srčane frekvencije za sva spomenuta razdoblja. Iz vrijednosti srčane frekvencije u mirovanju i srčane frekvencije postignute pri opterećenju od 50 W na biciklergometru dobivena je regresijska jednadžba korelacije frekvencije i izvršenog rada, na temelju koje je izračunavan izvršeni rad u spomenutim razdobljima. Iz primitka kisika pri opterećenju od 50 W na biciklergometru, primitka kisika na razini bazalnog metabolizma, srčane frekvencije pri opterećenju od 50 W i srčane frekvencije na razini bazalnog metabolizma izračunana je regresijska jednadžba korelacije srčane frekvencije i primitka kisika, i prikazan procijenjeni primitak kisika tijekom rada u svim razdobljima mjerenja. Primitak kisika na razini bazalnog metabolizma izračunan je iz energetske potrošnje dobivene jednadžbom po Harrisu i Benedictu, a primitak kisika pri opterećenju od 50 W iz nomograma koji se koristi pri ergometriji. Iz procijenjenog primitka kisika izračunavana je bruto energetska potrošnja za sva razdoblja mjerenja. Prosječna procijenjena bruto energetska potrošnja tijekom šest sati efektivnog rada ispitanice iznosila je 9.7±1.3 kJ/min,što odgovara kategoriji laganog industrijskog rada. Prosječni procijenjeni primitak kisika u istom razdoblju iznosio je 0,45±0,06 L/min, prosječno izvršeni mehanički rad 12,5±4,2 W, odnosno energetska efikasnost 7,8±1,4%

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 “self-annuitization” plan or the 401(k) “default” 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 “bet on death.” 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

Vertical structure of bottom Ekman tidal flows: Observations, theory, and modeling from the northern Adriatic

From September 2002 to May 2003, fifteen bottom‐ mounted, acoustic Doppler current profilers measured currents of the northern Adriatic basin. Tidal fluctuations at all seven of the major Adriatic frequencies were synthesized from a response tidal analysis of these measurements. Most observed tidal current ellipses were nearly reversing, but near the bottom, tidal current ellipses all shortened and broadened, semidiurnal currents led upper water column currents, and diurnal tidal current ellipse orientations rotated counterclockwise toward the bottom. Theoretical solutions for a tidally forced, bottom Ekman layer with vertical eddy viscosity of the form A z = β z + k were least squares fit to the observations. Average values were β = 3 · 10− 4 m/s and k = 5 · 10− 4 m2/s. The value of k was important in matching tidal orientation and phase changes, and a nonzero β was important in matching tidal amplitude changes. The Navy Coastal Ocean Model (NCOM) and the Quoddy model were also compared to the observations. The average RMS errors for the bottom Ekman layer were 0.22 cm/s for the best fit theory, 0.35 cm/s for NCOM, and 0.36 cm/s for Quoddy. A z structures from NCOM and Quoddy show that time variation in A z is relatively unimportant for Adriatic tides. The bottom shear stresses from theory were larger in magnitude than those from the bottom drag formulations in NCOM and Quoddy

Roles of the Nfu Fe-S targeting factors in the trypanosome mitochondrion

Iron–sulphur clusters (ISCs) are protein co-factors essential for a wide range of cellular functions. The core iron–sulphur cluster assembly machinery resides in the mitochondrion, yet due to export of an essential precursor from the organelle, it is also needed for cytosolic and nuclear iron–sulphur cluster assembly. In mitochondria all [4Fe–4S] iron–sulphur clusters are synthesised and transferred to specific apoproteins by so-called iron–sulphur cluster targeting factors. One of these factors is the universally present mitochondrial Nfu1, which in humans is required for the proper assembly of a subset of mitochondrial [4Fe–4S] proteins. Although most eukaryotes harbour a single Nfu1, the genomes of Trypanosoma brucei and related flagellates encode three Nfu genes. All three Nfu proteins localise to the mitochondrion in the procyclic form of T. brucei, and TbNfu2 and TbNfu3 are both individually essential for growth in bloodstream and procyclic forms, suggesting highly specific functions for each of these proteins in the trypanosome cell. Moreover, these two proteins are functional in the iron–sulphur cluster assembly in a heterologous system and rescue the growth defect of a yeast deletion mutant

Single-Molecule Studies of Origin Licensing Reveal Mechanisms Ensuring Bidirectional Helicase Loading

Loading of the ring-shaped Mcm2–7 replicative helicase around DNA licenses eukaryotic origins of replication. During loading, Cdc6, Cdt1, and the origin-recognition complex (ORC) assemble two heterohexameric Mcm2–7 complexes into a head-to-head double hexamer that facilitates bidirectional replication initiation. Using multi-wavelength single-molecule fluorescence to monitor the events of helicase loading, we demonstrate that double-hexamer formation is the result of sequential loading of individual Mcm2–7 complexes. Loading of each Mcm2–7 molecule involves the ordered association and dissociation of distinct Cdc6 and Cdt1 proteins. In contrast, one ORC molecule directs loading of both helicases in each double hexamer. Based on single-molecule FRET, arrival of the second Mcm2–7 results in rapid double-hexamer formation that anticipates Cdc6 and Cdt1 release, suggesting that Mcm-Mcm interactions recruit the second helicase. Our findings reveal the complex protein dynamics that coordinate helicase loading and indicate that distinct mechanisms load the oppositely oriented helicases that are central to bidirectional replication initiation.National Institutes of Health (U.S.) (NIH grant GM52339)National Institutes of Health (U.S.) (NIH grant R01 GM81648)G. Harold and Leila Y. Mathers FoundationNational Institutes of Health (U.S.) (NIH Pre-Doctoral Training Grant (GM007287))Howard Hughes Medical Institute (Investigator