Practical implementation of the Kelly criterion: optimal growth rate, number of trades, and rebalancing frequency for equity portfolios

We develop a general framework to apply the Kelly criterion to the stock market data, and consequently, to portfolio optimization. Under few conditions, using Monte Carlo simulations with different scenarios we prove that the Kelly criterion beats any other approach in many aspects. In particular, it maximizes the expected growth rate and the median of the terminal wealth. We also show that, under a normal distribution of returns, the Kelly criterion has the best performance in the long run. Next, we optimize a portfolio with the Kelly criterion with no leverage and no short selling conditions and show that this portfolio lays in the mean-variance efficient frontier and has higher expected return and higher variance, although it is less diversified, respect to the tangent portfolio optimized under the Markowitz approach. Finally, we implement a dynamic strategy applied on the European stock market data and compare the results between the tangent and the optimal Kelly portfolios. In a dynamic setting, the rolling Kelly portfolio outperforms competitors particularly in the case of rebalanced portfolios optimized with a 2-years window width

Cost utility analysis of Remdesivir and Dexamethasone treatment for hospitalised COVID-19 patients - a hypothetical study

Background: Sars-Cov-2 is a novel corona virus associated with significant morbidity and mortality. Remdesivir and Dexamethasone are two treatments that have shown to be effective against the Sars-Cov-2 associated disease. However, a cost-effectiveness analysis of the two treatments is still lacking. Objective: The cost-utility of Remdesivir, Dexamethasone and a simultaneous use of the two drugs with respect to standard of care for treatment Covid-19 hospitalized patients is evaluated, together with the effect of Remdesivir compared to the base model but based on alernative assumptions. Methods: A decision tree for an hypothetical cohort of Covid-19 hospitalized patients, from an health care perspective and a one year horizon is specified. Efficacy data are retrieved from a literature review of clinical trials, whilst costs and utility are obtained from other published studies. Results: Remdesivir, if health care costs are related to the days of hospitalization, is a cost saving strategy. Dexamethasone is cost effective with an ICER of $5208/QALY, and the concurrent use of Remdesivir and Dexamethasone is the most favorable strategy for higher level of willingness to pay thresholds. Moreover, if Remdesivir has a positive effect on mortality the utility is three times higher respect to base case. Whereas, if health care costs are not related to the length of patient hospitalization Remdesivir has an ICER respect to standard of care of$384412.8/QALY gained, which is not cost effective. We also find that Dexaamethasone is cost effective respect to standard care if we compute the cost for live saved with an ICER of $313.79 for life saved. The uncertainty of the model parameters is also tested through both a one-way deterministic sensitivity analysis and a probabilistic sensitivity analysis. Conclusion: We find that the use of Remdesivir and/or Dexamethasone is effective from an economic standpoint

Aerobic environment ensures viability and anti-oxidant capacity when seeds are wet with negative effect when moist: implications for persistence in the soil

Interchangeable effects of temperature, moisture content and oxygen on seed longevity have been mostly examined to estimate seed viability during long-term dry storage, whereas few experiments have studied seed viability under near-natural conditions to evaluate seed persistence in the soil. To this end, we artificially aged seeds of Ranunculus baudotii, a hydrophyte widely distributed in temporary ponds constituting an abundant soil seed bank. Seeds were exposed to controlled ageing at three different relative humidities (RH) under both aerobic and anoxic conditions. Their viability, water content, membrane damage, oxidative stress and anti-oxidant enzymatic defence activity were evaluated. Seed survival was longer at higher relative humidity (97% RH), and lowest at a relative humidity (90% RH) simulating moist but not waterlogged soils. Anoxic conditions showed a protective role on viability at lower moisture contents (70% RH). Seed viability was negatively associated with hydrogen peroxide content and correlated with anti-oxidant enzyme activities, but not with membrane damage. Altogether, these results suggest negative roles for moist soils and anoxia in determining seed persistence in the field, but at higher moisture contents the negative effects of anaerobia diminished. The anti-oxidant system activation, even under unfavourable conditions, might recover seeds once all protective processes can operate, pointing out the plasticity of mechanisms involved in seed loss viability

Coordination between leaf and root traits in Mediterranean coastal dune plants

Plant trait-based functional spectra are crucial to assess ecosystem functions and services. Whilst most research has focused on aboveground vegetative traits (leaf economic spectrum, LES), contrasting evidence on any coordination between the LES and root economic spectrum (RES) has been reported. Studying spectra variation along environmental gradients and accounting for species' phylogenetic relatedness may help to elucidate the strength of coordination between above- and belowground trait variation.center dot We focused on leaf and root traits of 39 species sampled in three distinct habitats (front, back and slack) along a shoreline-inland gradient on coastal dunes. We tested, within a phylogenetic comparative framework, for the presence of the LES and RES, for any coordination between these spectra, and explored their relation to variation in ecological strategies along this gradient.center dot In each habitat, three-quarters of trait variation is captured in two-dimensional spectra, with species' phylogenetic relatedness moderately influencing coordination and trade-off between traits. Along the shoreline-inland gradient, aboveground traits support the LES in all habitats. Belowground traits are consistent with the RES in the back-habitat only, where the environmental constraints are weaker, and a coordination between leaf and root traits was also found, supporting the whole-plant spectrum (PES).center dot This study confirms the complexity when seeking any correlation between the LES and RES in ecosystems characterized by multiple environmental pressures, such as those investigated here. Changes in traits adopted to resist environmental constraints are similar among species, independent of their evolutionary relatedness, thus explaining the low phylogenetic contribution in support of our results

Is the Sardinian Blue Zone the New Shangri-La for mental health? Evidence on depressive symptoms and its correlates in late adult life span

Background: An area of extraordinary longevity (i.e., Sardinian Blue Zone) characterized by a very high prevalence of long-lived successful agers has been validated in Sardinia, an Italian island located in the Mediterranean Sea. Aims: This study was primarily aimed at examining whether dietary habits (intake of vegetables and fruit, animal-derived proteins, and carbohydrates-rich food), time spent on hobbies, subjective physical health, and socio-cultural context (Sardinian Blue Zone vs. another Sardinian rural area) predicted self-reported depressive symptoms in older adults recruited in the Sardinian Blue Zone and another Sardinian rural area not being characterized by a higher prevalence of long-lived individuals. Methods: Three hundred and eighteen community-dwellers, age 65 years and older, 188 females and 130 males (Mage = 79.1 years, SD = 6.9 years) were recruited from the Sardinian Blue Zone and another Sardinian rural area. Each participant individually completed a battery of instruments to assess lifestyle, food habits, perceived physical health, and depressive symptoms through the CES-D inventory. Results: Significant associations were found between depressive signs, perceived physical health, time spent gardening, proteins, and carbohydrates intake, respectively. Approximately 17% of the variance in the CES-D condition was predicted by socio-cultural context, perceived physical health, and gardening. Participants recruited in the Sardinian Blue Zone spent more time gardening and self-reported better physical health. Conclusions: current results suggest that a socio-cultural context where people age well (i.e., the Sardinian Blue Zone), and a healthy and physically active lifestyle are crucial for promoting well-being in late adulthood

Scattering reduction and resonant trapping of flexural waves: Two rings to rule them

In this paper, we discuss two problems concerning scattering and localisation of flexural waves in structured elastic plates. Firstly, we compare the scattering amplitudes of waves in a thin plate, generated by a point source, due to a single mass and to a large number of smaller masses, having the same equivalent mass and located around a circle. We show that in the second case, the scattering can be reduced, in particular in the medium-and high-frequency regimes. Secondly, we develop a homogenised model for a double-ring cluster of spring-mass resonators, connected to an elastic thin plate. We determine the conditions for which the plate exhibits vibration modes trapped between the two rings. Further, we show that the frequencies of the localised modes can be tuned by varying the geometry of the two rings and the characteristics of the resonators. The analytical results are corroborated by numerical simulations performed with independent finite element models

Unusual metastasis of papillary renal cell carcinoma to the pyriform sinus: case report

Renal cell carcinoma is the third most common cause of distant metastasis to the head and neck. Renal cell carcinoma metastasis should be considered in differential diagnosis when patients with a clinical history of renal cell carcinoma show a head and neck mass

Polymers of Intrinsic Microporosity derived from a carbocyclic analogue of Tröger's base

Tröger's base (TB) is often used as a building block for the synthesis of Polymers of Intrinsic Microporosity (PIMs) due to its rigid bicyclic V-shaped structure. In this study the TB component in the structure of a PIM is replaced by 2,3:6,7-dibenzobicyclo[3.3.1]nonane, a purely carbocyclic analogue of TB. This modification results in only a slightly reduced amount of microporosity as determined using nitrogen adsorption. Further comparisons with previously reported PIMs indicate that this building unit (and therefore TB) is significantly less effective for the generation of intrinsic microporosity than spirobisindane, a commonly used structural unit for PIM synthesis. It appears that the V-shape of the 2,3:6,7-dibenzobicyclo[3.3.1]nonane and TB units allows closer contact between polymer chains thereby enhancing packing efficiency

De‐novo abnormal uteroplacental circulation in third trimester: pregnancy outcome and pathological implications

Objective Hypertensive disorders of pregnancy (HDP) are associated with impaired placentation, as evidenced by abnormal uterine artery (UtA) Doppler. In normal pregnancy, mean UtA pulsatility index (PI) shows a progressive decline with gestational age (GA). However, previous studies have reported that a proportion of pregnancies demonstrate worsening UtA Doppler in later pregnancy. The aim of this study was to investigate the incidence of HDP according to the change in mean UtA‐PI between the second and third trimesters. Methods This was a retrospective cohort study of singleton pregnancies between March 1997 and March 2016 that underwent longitudinal UtA Doppler assessment in the second and third trimesters. All parameters were converted into centiles or multiples of the median (MoM), adjusting for GA. The study cohort was divided into two groups, according to change in mean UtA‐PI between the second and third trimesters (those with a decrease or no change and those with an increase). HDP included women who developed pre‐eclampsia and/or gestational hypertension. Logistic regression analysis was used to adjust for potential confounders. Results The analysis included 5887 pregnancies. The incidence of HDP was significantly higher in the group with increasing mean UtA‐PI compared with those without (7.9% vs 5.8%; P = 0.002). Logistic regression analysis demonstrated that both third‐trimester UtA‐PI MoM (odds ratio (OR), 7.35; 95% CI, 4.66–11.6; P < 0.001) and stable or decrease in UtA‐PI MoM between the second and third trimesters (OR, 0.43; 95% CI, 0.31–0.60; P < 0.001) were significant independent predictors for the development of HDP. Conclusion Worsening of UtA Doppler is associated with HDP, independent of the value recorded in the second trimester

Microwave heating improvement: permittivity characterization of water–ethanol and water–NaCl binary mixtures

Microwave heating offers a lot of advantages compared to conventional heating methods in the chemical reactions field due to its positive effects on reaction time and selectivity. Dielectric properties, and in particular permittivity, of substances and mixtures, are important for the optimization of microwave heating processes; notwithstanding this, specific databases are poor and far from being complete, and in the scientific literature very little data regarding these properties can be found. In this work, impedance measurements were carried out using a specially designed system to get the real and imaginary parts of the dielectric constant. The apparatus was tested in the estimation of permittivity of water–ethanol and water–NaCl mixtures, varying their composition to obtain a wide range of permittivity values. The results were compared to literature data and fitted with available literature models to verify the correspondence between them, finding that permittivity dependence on mixture composition can be effectively described by the models