A square root of the harmonic oscillator

Allowing for the inclusion of the parity operator, it is possible to construct an oscillator model whose Hamiltonian admits an EXACT square root, which is different from the conventional approach based on creation and annihilation operators. We outline such a model, the method of solution and some generalizations.Comment: RevTex, 10 pages in preprint form, no figure

From plasmodesma geometry to effective symplasmic permeability through biophysical modelling

Regulation of molecular transport via intercellular channels called plasmodesmata (PDs) is important for both coordinating developmental and environmental responses among neighbouring cells, and isolating (groups of) cells to execute distinct programs. Cell-to-cell mobility of fluorescent molecules and PD dimensions (measured from electron micrographs) are both used as methods to predict PD transport capacity (i.e., effective symplasmic permeability), but often yield very different values. Here, we build a theoretical bridge between both experimental approaches by calculating the effective symplasmic permeability from a geometrical description of individual PDs and considering the flow towards them. We find that a dilated central region has the strongest impact in thick cell walls and that clustering of PDs into pit fields strongly reduces predicted permeabilities. Moreover, our open source multi-level model allows to predict PD dimensions matching measured permeabilities and add a functional interpretation to structural differences observed between PDs in different cell walls

Global Supply for Carbon Sequestration: Identifying Least-Cost Afforestation Sites Under Country Risk Consideration

We have provided a framework for Identifying least-cost sites for carbon sequestration and deriving carbon sequestration cost curves at a global level in a scenario of limited information. The method is based on determining sequestration costs for geographical explicit units (50km grid cells), based on GIS parameters on land-use and ecosystem properties, and aggregated economic data. Special attention is given to country risk considerations and the sensitivity to special datasets. Our model results suggest that within 20 years and considering a carbon price of $50/tC, afforestation could offset one year of global carbon emissions in the energy sector. However, if we account for country risk considerations - associated with political, economic and and financial risks - the carbon supply is reduced to about 60%. With respect to the geography of supply, illustrated by grid-scale maps, we find that most least-cost projects projects are located in Africa, South America and Asia, assuming a 5% discount rate without risk. Once risk is factored into the equation, these countries become more expensive to operate in

Callose deposition and symplastic connectivity are regulated prior to lateral root emergence.

Root growth is critical for the effective exploitation of the rhizosphere and productive plant growth. Our recent work(1) showed that root architecture was dependent upon the degree of symplastic connectivity between neighboring cells during the specification of lateral root primordia and was affected by genes regulating callose deposition at plasmodesmata (PD). Here we provide additional evidence that both symplastic connectivity and callose are also important during the later phase of lateral root development: emergence. Callose immunolocalization assays indicated that transient symplastic isolation of the primordium occur immediately prior to emergence through the overlaying tissues to produce the mature lateral root.(1) Here we could corroborate these results by analyzing the mobility of a symplastic tracer and the expression of PD genes in lateral roots and in response to auxins. Moreover, we show that altering callose deposition affects the number of emerged lateral roots suggesting that PD regulation is important for emergence

To App or Not to App? Understanding public resistance to COVID-19 digital contact tracing and its criminological relevance

In the context of the COVID-19 pandemic, digital contact tracing has been developed and promoted in many countries as a valuable tool to help the fight against the virus, allowing health authorities to react quickly and limit contagion. Very often, however, these tracing apps have faced public resistance, making their use relatively sparse and ineffective. Our study relies on an interdisciplinary approach that brings together criminological and computational expertise to consider the key social dynamics underlying people’s resistance to using the NHS contact-tracing app in England and Wales. The present study analyses a large Twitter dataset to investigate interactions between relevant user accounts and identify the main narrative frames (lack of trust and negative liberties) and mechanisms (polluted information, conspiratorial thinking and reactance) to explain resistance towards use of the NHS contact-tracing app. Our study builds on concepts of User eXperience (UX) and algorithm aversion and demonstrates the relevance of these elements to the key criminological problem of resistance to official technologies

Performance analysis of energy detection over hyper-Rayleigh fading channels

This study investigates the performance of energy detection (ED)-based spectrum sensing over two-wave with diffused power (TWDP) fading channels, which have been found to provide accurate characterisation for a variety of fading conditions. A closed-form expression for the average detection probability of ED-based spectrum sensing over TWDP fading channels is derived. This expression is then used to describe the behaviour of ED-based spectrum sensing for a variety of channels that include Rayleigh, Rician and hyper-Rayleigh fading models. Such fading scenarios present a reliable behavioural model of machine-to-machine wireless nodes operating in confined structures such as in-vehicular environments

A Gamified Approach Towards Identifying Key Opportunities and Potential Sponsors for the Future of F1 Racing in a Declining Car Ownership Environment

This research work aims to propose new approaches towards identifying key opportunities and potential sponsors for the future of F1 racing in an environment with declining car ownership, without resorting to endless licensing agreements. The paper presents a gamification approach on which an innovative and disruptive operations framework can be developed to help, without operational complexity and commitment, F1 teams gain new customers (fans) and recapture essential markets and targets groups. The paper also contributes on establishing a base for effective strategy development based on the user’s/player’s engagement and behavior. Furthermore, this work extends towards the analysis of the game’s operations and the marketing initiatives needed to succeed. The proposed approach varies from OHH (out of home advertising), interactive marketing, celebrities, F1 drivers’ endorsements, and other related supportive initiatives such as search engine optimization on online research platforms and other promotion and marketing dissemination initiatives

Evaluación nutricional de ensilajes con diferentes niveles de inclusión de cáscara de naranja (Citrus sinensis) y digestibilidad in vivo como alternativa energética para alimentación de cerdos

El presente estudio evaluó el valor nutricional de dietas con base en cáscara de naranja (Citrus sinensis), en ensilaje. Los tratamientos consistieron en 5 niveles de inclusión de cáscara de naranja 0, 10, 20, 30 y 40 %; se estimó caracterización organoléptica (color y olor durante los tiempos de fermentación (1, 3, 7, 21 y 28 días). Conjuntamente se determinó pH, materia seca (MS), proteína cruda (PC), extracto etéreo (EE), fibra cruda (FC), cenizas (CEN) y extracto no nitrogenado (ENN). Se analizaron coeficientes de digestibilidad (CD), con la técnica de bolsa dacrón móvil (TBDM) y un cerdo de 25 kg de peso, al cual previamente se le implantó una cánula duodenal; para esta prueba se escogieron los tiempos de fermentación (3, 7, 21 días) y los tratamientos con inclusión de cáscara de naranja T2 (10 %), T3 (20 %), T4 (30 %) y el control. Por último se realizó aproxima- ción económica de dietas. La evaluación organoléptica demostró variabilidad en color, debido al cítrico presente en los tratamientos; el olor fue influenciado por la presencia de ácidos, que proporcionaron olor agradable. El análisis químico fue significativo (p<0.01), entre tratamientos y tiempos de fermentación, resultando un compor- tamiento favorable para T3 con valores promedios de pH (4,19), MS (49.7 %), PC (23.3 %), FC (1.8 %), EE (4.4%), CEN (5.3 %) y ENN (62.29 %). Los tratamientos T2 y T3 reportaron CD mayores al control. Se propone el ensilaje cítrico con nivel de 20% para dietas iniciadoras de cerdos

Brassinosteroids en route

Brassinosteroid (BR) hormones promote root growth by controlling meristem size and cell elongation, but the mechanism of BR transport remains elusive. A new study shows that BR precursors move via intercellular pores called plasmodesmata to modulate BR cellular levels and their signaling functions