Mortality-Indexed Annuities

Longevity risk has become a major challenge for governments, individuals, and annuity providers in most countries, and especially its aggregate form, i.e. the risk of unsystematic changes to general mortality patterns, bears a large potential for accumulative losses for insurers. As obvious risk management tools such as (re)insurance or hedging are less suited to manage an annuity provider’s exposure to aggregate longevity risk, the current paper proposes a new type of life annuities with benefits contingent on actual mortality experience, and it also details actuarial aspects of implementation. Similar adaptations to conventional product design exist in investment-linked annuities, and a role model for long-term contracts contingent on actual cost experience is found in German private health insurance so that the idea is not novel in general, but it is in the context of longevity risk. By not or re-transferring the systematic longevity risk insurers may avoid accumulative losses so that the primary focus in an extensive Monte-Carlo simulation is on the question of whether and to what extent such products are also advantageous for policyholders in contrast to a comparable conventional annuity product

Select Birth Cohorts

Worldwide demographic changes and their implications for governments, corporations, and individuals have been in the focus of public interest for quite some time due to the fiscal risk related to adequate retirement benefits. Through a more detailed analysis of mortality data an additional type of risk can be identified: differences in mortality improvements by birth year, also known as "cohort effects." Previous contributions have, however, not formalized a suitable measure to further investigate mortality improvements but rather relied on graphical representations without particular focus on individual cohorts but groups of the overall population. No criterion to identify single birth year cohorts as select has been established. A simple criterion for identifying select cohorts is proposed and used here to what country mortality data reveals about the mortality and longevity experience of cohorts. Select cohorts are rare but can be quite different from surrounding cohorts and so may generate financial risks that need to be hedged naturally or artificially with new ART instruments

Assessing Investment and Longevity Risks within Immediate Annuities

Life annuities provide a guaranteed income for the remainder of the recipient’s lifetime, and therefore, annuitization presents an important option when choosing an adequate investment strategy for the retirement ages. While there are numerous research articles studying annuities from a pensioner’s point of view, thus far there have been few contributions considering annuities from the provider’s perspective. In particular, to date there are no surveys of the general risks within annuity books. The present paper aims at filling this gap: Using a simulation framework, it provides a long-term analysis of the risks within annuity books. In particular, the joint impact of mortality risks and investment risks as well as their respective influences on the insurer’s financial situation are studied. The key finding is that, under the model specifications and using annuity data from the United Kingdom, the risk premium charged for aggregate mortality risk seems to be very large relative to its characteristics. Possible reasons as well as economic implications are provided, and potential caveats are discussed

Select Birth Cohorts

Worldwide demographic changes and their implications for governments, corporations, and individuals have been in the focus of public interest for quite some time due to the fiscal risk related to adequate retirement benefits. Through a more detailed analysis of mortality data an additional type of risk can be identified: differences in mortality improvements by birth year, also known as "cohort effects." Previous contributions have, however, not formalized a suitable measure to further investigate mortality improvements but rather relied on graphical representations without particular focus on individual cohorts but groups of the overall population. No criterion to identify single birth year cohorts as select has been established. A simple criterion for identifying select cohorts is proposed and used here to what country mortality data reveals about the mortality and longevity experience of cohorts. Select cohorts are rare but can be quite different from surrounding cohorts and so may generate financial risks that need to be hedged naturally or artificially with new ART instruments.mortality improvement; longevity trend; select cohort; longevity risk

Assessing Investment and Longevity Risks within Immediate Annuities

Life annuities provide a guaranteed income for the remainder of the recipient’s lifetime, and therefore, annuitization presents an important option when choosing an adequate investment strategy for the retirement ages. While there are numerous research articles studying annuities from a pensioner’s point of view, thus far there have been few contributions considering annuities from the provider’s perspective. In particular, to date there are no surveys of the general risks within annuity books. The present paper aims at filling this gap: Using a simulation framework, it provides a long-term analysis of the risks within annuity books. In particular, the joint impact of mortality risks and investment risks as well as their respective influences on the insurer’s financial situation are studied. The key finding is that, under the model specifications and using annuity data from the United Kingdom, the risk premium charged for aggregate mortality risk seems to be very large relative to its characteristics. Possible reasons as well as economic implications are provided, and potential caveats are discussed.Annuities; Lee-Carter Model; Longevity Risk

Mortality-Indexed Annuities

Longevity risk has become a major challenge for governments, individuals, and annuity providers in most countries, and especially its aggregate form, i.e. the risk of unsystematic changes to general mortality patterns, bears a large potential for accumulative losses for insurers. As obvious risk management tools such as (re)insurance or hedging are less suited to manage an annuity provider’s exposure to aggregate longevity risk, the current paper proposes a new type of life annuities with benefits contingent on actual mortality experience, and it also details actuarial aspects of implementation. Similar adaptations to conventional product design exist in investment-linked annuities, and a role model for long-term contracts contingent on actual cost experience is found in German private health insurance so that the idea is not novel in general, but it is in the context of longevity risk. By not or re-transferring the systematic longevity risk insurers may avoid accumulative losses so that the primary focus in an extensive Monte-Carlo simulation is on the question of whether and to what extent such products are also advantageous for policyholders in contrast to a comparable conventional annuity product.Longevity risk; systematic risk; risk avoidance; mortality-indexed annuities

Bioeffector products for plant growth promotion in agriculture : modes of action and the application in the field

Modern agriculture faces a conflict between sustainability and the demand for a higher food production. This conflict is exacerbated by climate change and its influence on vegetation, ecology and human society. To reduce land use, the reduction of yield losses and food waste is crucial. Moreover a sustainable intensification is necessary to increase yields, while at the same time input of limited resources such as drinking water or fertilizer should be kept as low as possible. This might be achieved by improving nutrient recycling and plant resistance to abiotic or biotic stress. Bioeffectors (BE) comprise seaweed or plant extracts and microbial inoculums that may stimulate plant growth by phytohormonal changes and increase plant tolerance to abiotic stress (biostimulants), solubilize or mobilize phosphorus from sparingly soluble sources such as Al/Fe or Ca-phosphates in the soil, rock phosphates, recycling fertilizer or organic phosphorus sources like phytate (biofertilizer), or improve plant resistance against pathogens by induced-systemic resistance (ISR) or antibiosis (biocontrol). For this study, in total 18 BE products were tested in germination, pot and field experiments for their potential to improve plant growth, cold stress tolerance, nutrient acquisition and yield in maize and tomato. Additionally, a gene expression analysis in maize was performed using whole transcriptome sequencing (RNA-Seq) after the application of two potential plant growth promoting rhizobacteria (PGPR), the Pseudomonas sp. strain DSMZ 13134 Proradix and the Bacillus amyloliquefaciens strain FZB42. Seaweed products supplemented with high amounts of the micronutrients Zn and Mn were effective in reducing detrimental cold stress reactions in maize whereas microbial products and seaweed extracts without micronutrient supplementation failed under the experimental conditions. At optimal temperature the product containing the Pseudomonas sp. strain was repeatedly able to stimulate root and shoot growth of maize plants whereas in tomato only in heat-treated soil substrate significant effects were observed. Results indicate that the efficacy of the product was mainly attributed to stimulation or shifts in the soil microbial community. Additionally, the FZB42 strain was able to stimulate root and plant growth in some experiments whereas the effects were less reproducible and more sensitive to environmental conditions. Fungal BE products were less effective in plant growth stimulation and showed detrimental effects in some experiments. Under the applied experimental conditions BE-derived plant growth stimulation mainly was attributed to biostimulation but aspects of biofertilization or biocontrol cannot be excluded, as all experiments were conducted in non-sterile soil substrates. Root and shoot growth are stimulated in response to hormonal shifts. In the gene expression analysis only weak responses to BE treatments were observed, as previously reported from other studies conducted under non-sterile conditions. Nevertheless, some plant stress responses were observed that resembled in some aspects those reported for phosphorus (P) deficiency in others those reported for ISR/SAR. Especially the activation of plant defence mechanisms, such as the production of secondary metabolites, ethylene production and reception and the expression of several classes of stress-related transcription factors, including JA-responsive JAZ genes, was observed. It also seems probable that in plants growing in PGPR-drenched soils, especially at high application rates, a sink stimulation for assimilates triggers changes in photosynthetic activity and root growth leading to an improved nutrient acquisition. Nevertheless, due to the complexity of interactions in natural soil environments as well as under practice conditions, a designation of a distinct mode of action for plant growth stimulation by microbial BEs is not realistic. A comparison of the overall results with those reported in literature or other working groups in a common research project (Biofector) supported the often-reported low reproducibility of plant growth promotion effects by BE products under applied conditions. Factors that influenced BE efficacy were application time and rates, temperature, soil buffer capacity, phosphorus sources and nitrogen fertilization, light conditions and the soil microbial community. Results indicate that in maize cultivation seed treatment is the most economic application technique for microbial products whereas for vegetable or high-value crops with good economic benefit soil drenching is recommended. For seaweed extracts foliar application seems to be the most economic and efficient choice. Furthermore, results emphasize the importance of a balanced natural soil microflora for plant health and yield stability.Die moderne Landwirtschaft steht vor einem Konflikt zwischen Nachhaltigkeit und der Forderung nach einer höheren Nahrungsmittelproduktion. Der Einsatz begrenzter Ressourcen wie Trinkwasser sowie umweltschädlicher Stoffe (Düngemittel, Pestizide) sollte so gering wie möglich gehalten werden. Dies kann durch Verbesserungen im Nährstoffrecycling sowie durch Stärkung der Pflanzenresistenz gegenüber abiotischem oder biotischem Stress erreicht werden. Bio-Effektoren (BE) umfassen Algen- oder Pflanzenextrakte und mikrobielle Inokula, die das Pflanzenwachstum durch phytohormonelle Veränderungen stimulieren und die Pflanzenverträglichkeit gegenüber abiotischem Stress erhöhen (Biostimulanzien), Phosphor aus schwerlöslichen Quellen wie Al/Fe oder Ca-Phosphaten im Boden, Steinphosphaten, Recyclingdüngern oder organischen Phosphorquellen wie Phytat mobilisieren (Bio-Dünger) oder zur Verbesserung der Pflanzenresistenz gegen Pathogene durch induzierte systemische Resistenz (ISR) oder Antibiose (Bio-Pestizide) beitragen. Insgesamt wurden 18 BE-Produkte in Keimungs-, Topf- und Feldexperimenten auf ihr Potenzial zur Verbesserung des Pflanzenwachstums, der Kältestresstoleranz, der Nährstoffaufnahme und des Ertrags in Mais und Tomate getestet. Zusätzlich wurde eine Genexpressionsanalyse in Mais durchgeführt unter Verwendung der vollständigen Transkriptomsequenzierung (RNA-Seq) nach der Anwendung von zwei potentiell pflanzenwachstumsfördernden Rhizobakterien (PGPR), dem Pseudomonas sp. Stamm DSMZ 13134 "Proradix" und dem Bacillus amyloliquefaciens Stamm FZB42. Meeresalgenprodukte, die mit hohen Mengen der Mikronährstoffe Zn und Mn angereichert wurden, konnten Kältestressreaktionen bei Mais wirksam reduzieren, während mikrobielle Produkte und Meeresalgenextrakte ohne Mikronährstoffergänzung unter den Testbedingungen erfolglos waren. Bei optimaler Temperatur war das Produkt, das den Pseudomonas-Stamm enthält, wiederholt in der Lage, Wurzel- und Sprosswachstum von Maispflanzen zu stimulieren, während in Tomaten nur in wärmebehandeltem Bodensubstrat signifikante Effekte beobachtet wurden. Die Ergebnisse legen nahe, dass die Wirksamkeit des Produkts hauptsächlich auf Stimulation oder Veränderungen in der mikrobiellen Gemeinschaft im Boden zurückzuführen ist. Auch der FZB42-Stamm war in der Lage, das Wachstum von Wurzeln und Pflanzen in einigen Experimenten zu stimulieren, während die Effekte weniger reproduzierbar und empfindlicher für Umweltbedingungen waren. Pilzliche BE-Produkte waren bei der Pflanzenwachstumsstimulation weniger effizient und zeigten in einigen Experimenten auch schädliche Wirkungen. Unter den angewandten experimentellen Bedingungen scheint die BE-abgeleitete Pflanzenwachstumsstimulation hauptsächlich auf Biostimulation zurückzuführen zu sein, aber Aspekte der Bio-Düngung oder Bio-Kontrolle können nicht ausgeschlossen werden, da alle Experimente in nicht-sterilen Bodensubstraten durchgeführt wurden. Die Stimulation des Wurzelwachstums und der Sprosswachstumsrate ist eine Reaktion auf hormonelle Veränderungen. Die Genexpression zeigte nur schwache Reaktionen auf die BE-Behandlungen, wie bereits aus anderen Studien unter nicht-sterilen Bedingungen berichtet wurde. Trotzdem wurden einige pflanzliche Stressreaktionen beobachtet, die entweder für Phosphor (P)-Mangel oder aber ISR / SAR als typisch gelten. Insbesondere die Aktivierung von Abwehrmechanismen wie die Produktion von Sekundärmetaboliten, die Ethylenproduktion und -rezeption sowie die Expression mehrerer Klassen stressbedingter Transkriptionsfaktoren, einschließlich JA-responsiver JAZ-Gene, wurde beobachtet. Es scheint auch wahrscheinlich, dass in Pflanzen, die in PGPR-durchtränkten Böden wachsen, insbesondere bei hohen Aufwandmengen, eine Senkenstimulation für Assimilate die Photosyntheserate erhöht sowie Veränderungen im Wurzelwachstum auslöst, die zu einer verbesserten Nährstoffaufnahme führen können. Die Bestimmung eines speziellen Wirkungs-mechanismus ist jedoch durch die Komplexität der Interaktionen im Boden nicht möglich. Ein Vergleich der Gesamtergebnisse mit denen, die in der Literatur oder anderen Arbeitsgruppen berichtet wurden, unterstützt die oft berichtete geringe Reproduzierbarkeit von Pflanzenwachstumseffekten durch BE-Produkte unter Praxisbedingungen. Faktoren, die die BE-Wirksamkeit beeinflussen, sind Applikationszeit und -rate, Temperatur, Bodenpufferkapazität, Phosphor-Quelle, Stickstoff-Düngung, Lichtbedingungen sowie die mikrobielle Gemeinschaft des Bodens. Die Ergebnisse zeigen zudem, dass Saatgutbehandlung die wirtschaftlichste Anwendungstechnik für mikrobielle Produkte im Maisanbau ist, wobei für hochpreisige Kulturen im Gemüsebau konzentrierte Bodenapplikation empfohlen ist. Für Algenextrakte scheint Blattapplikation die beste Wahl zu sein. Die Ergebnisse zeigen zudem, wie wichtig eine ausgewogene, natürliche Bodenmikroflora für die Pflanzengesundheit und Ertragsstabilität ist

Variable training but not sleep improves consolidation of motor adaptation

How motor memory consolidates still remains elusive. Consolidation of motor skills has been shown to depend on periods of sleep. Conversely, motor adaptation during tasks not dependent on the hippocampus may not depend on sleep. Some research suggests that the training schedule affects the sleep dependency of motor adaptation tasks. Here, we investigated whether sleep differentially affects memory consolidation that depends on the training schedule. Healthy men were trained with their dominant, right hand on a force-field adaptation task and re-tested after an 11-h consolidation period involving overnight sleep (Sleep) or daytime wakefulness (Wake). Retesting included a transfer test of the non-dominant hand. Half of the subjects in each group adapted to different force-field magnitudes during training with low inter-trial force variability (Sleep-Blocked; Wake-Blocked), and the other half were trained with a high-variability schedule (Sleep-Random; Wake-Random). EEG was recorded during task execution and overnight polysomnography. Consolidation was comparable between Wake and Sleep groups, although performance changes over sleep correlated with sleep spindles nesting in slowwave upstates. Higher training variability improved retest performance, including transfer learning, and these improvements correlated with higher alpha power in contralateral parietal areas. These enhanced consolidation effects might be fostered by feedback rather than feedforward mechanisms

Nerfbusters: Removing Ghostly Artifacts from Casually Captured NeRFs

Casually captured Neural Radiance Fields (NeRFs) suffer from artifacts such as floaters or flawed geometry when rendered outside the camera trajectory. Existing evaluation protocols often do not capture these effects, since they usually only assess image quality at every 8th frame of the training capture. To push forward progress in novel-view synthesis, we propose a new dataset and evaluation procedure, where two camera trajectories are recorded of the scene: one used for training, and the other for evaluation. In this more challenging in-the-wild setting, we find that existing hand-crafted regularizers do not remove floaters nor improve scene geometry. Thus, we propose a 3D diffusion-based method that leverages local 3D priors and a novel density-based score distillation sampling loss to discourage artifacts during NeRF optimization. We show that this data-driven prior removes floaters and improves scene geometry for casual captures.Comment: ICCV 2023, project page: https://ethanweber.me/nerfbuster

Dreamento: an open-source dream engineering toolbox for sleep EEG wearables

We introduce Dreamento (Dream engineering toolbox), an open-source Python package for dream engineering utilizing the ZMax (Hypnodyne Corp., Sofia, Bulgaria) headband sleep wearable. Dreamento main functions are (1) real-time recording, monitoring, analysis, and stimulation in a graphical user interface (GUI) (2) and offline post-processing of the resulting data. In real-time, Dreamento is capable of (1) recording data, (2) visualizing data, including power-spectrum analysis and navigation, (3) automatic sleep-scoring, (4) sensory stimulation (visual, auditory, tactile), (5) establishing text-to-speech communication, and (6) managing the annotations of automatic and manual events. The offline functionality aids in post-processing the acquired data with features to reformat the wearable data and integrate it with non-wearable recorded modalities such as electromyography. While the primary application of Dreamento was developed for (lucid) dreaming studies, it is open to being adapted for other purposes and measurement modalities