885 research outputs found
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Identifying the Genetic Mechanism of Ethylene-Inducible Fruit Abscission in Sweet Cherry
Sweet cherry (Prunus avium, L.) belongs to the Amygdaloideae subfamily in the Rosaceae family and is related to Peach (Prunus persica, L.) which presents a classical example of climacteric ripening along with members in other sub-families such as Apple (Malus x domestica Borkh). While the fruit ripening process in sweet cherry is non-climacteric, a novel response to ethylene has been observed in a subset of cultivars, e.g., 'Bing', where a pre-harvest canopy-wide application of exogenous ethylene results in the formation of a distinct pedicel-fruit abscission zone. This decreases the force required to separate fruit from pedicel, presenting the possibility of harvesting the fruit mechanically. Some cultivars, e.g., 'Chelan', maintain a high pedicel fruit retention force, while the abscission zone in 'Skeena' develops without exogenous ethylene. This natural spectrum of phenotypes for ethylene-inducible abscission zone formation presents an interesting forward genetics model to unravel the underlying molecular mechanism. This is critical for a perennial crops species where reverse genetics approaches are not feasible due to the lack of genetic resources available in annual model system crops. Understanding the causal molecular and genetic underpinnings of the inducible abscission zone formation offers the potential to expand the basic knowledge of ethylene's role in a non-climacteric fruit crop. Practical applications from this work include precision in timing the application of chemicals that induce abscission zone formation in other non-climacteric horticultural crops to enable mechanical harvesting, efficiently manage labor and enhance safety. My research used a genomics approach to refine limited genomic data for the 'Stella' genotype by resequencing five additional genotypes: 'Bing', 'Kimberly', 'Glory', 'Staccato' and 'Sweetheart'. Genes involved in ethylene inducible fruit abscission were then characterized using a developmental time-course transcriptomic approach. The results are presented in the following chapters. Chapter 1: A international collaboration established the reference genome for sweet cherry and outlines the rationale for strategies used. Chapter 2: Multiple approaches to identify polymorphisms in genomic data were evaluated. Chapter 3: The results of the developmental time course, genotypic, and tissue specific transcriptome analysis that enabled the identification of co-expressed sequences during ethylene-induced abscission are described.; This is an abstract
Virtue Ethics for Christians
If one would tackle any major problem in life it is helpful to observe the comprehensive nature of the thing from an external vantage point before diving into the gritty details. This is also described as grasping the “big picture” or getting a birds-eye-view on the problem. I think that this holistic approach is helpful when dealing with ethical issues as well. In this paper I will first define the common approaches to normative ethics and then point out reasons that one approach in particular is a superior ethical framework from which Christians should work
Estimación de biomasa aérea en pasturas templadas de sistemas lecheros pastoriles
En sistemas lecheros pastoriles la estacionalidad y la variación interanual de la productividad forrajera constituyen la principal restricción tanto biofísica como económica. La medición de biomasa aérea permite estimar el forraje disponible y la productividad forrajera. Para medir la biomasa aérea de un recurso el productor puede utilizar tanto métodos directos como indirectos. El presente trabajo estudia estos métodos de estimación de biomasa aérea en una pastura mixta (trébol blanco, trébol rojo y cebadilla) de un establecimiento lechero ubicado en Suipacha, Pcia. de Buenos Aires (Argentina). Entre 2007 y 2008 tres observadores recorrieron un potrero cada tres semanas y estimaron la biomasa aérea presente en 12 unidades de muestreo de 0,09 m². Luego, se cortó al ras del suelo el material presente en cada unidad, se recolectó y se llevó al laboratorio para su procesamiento. Los métodos indirectos utilizados fueron la estimación visual, el pasturómetro y la regla graduada. Se generaron ecuaciones de calibración para cada método a distintas escalas temporales (Capítulo 2). Los resultados sugieren que los métodos indirectos son buenos estimadores de la biomasa aérea obtenida por cortes, tanto a escala anual como a escala estacional. En algunos casos, la precisión de la calibración del método estuvo afectada por la estación considerada. La validación de los modelos se realizó a dos niveles de análisis (Capítulo 3). La validación con una ecuación por estación sugiere que el método más preciso fue la estimación visual. En cambio, la validación con una ecuación para todo el período sugiere que todos los métodos fueron poco precisos. Algunos de los métodos estudiados en este trabajo, como la estimación visual y el pasturómetro, se presentan como promisorios. El uso de métodos sencillos, económicos y prácticos como estos permitiría mejorar el manejo y la eficiencia de los sistemas de producción de leche de base pastoril
Exfoliated hexagonal BN as gate dielectric for InSb nanowire quantum dots with improved gate hysteresis and charge noise
We characterize InSb quantum dots induced by bottom finger gates within a
nanowire that is grown via the vapor-liquid-solid process. The gates are
separated from the nanowire by an exfoliated 35\,nm thin hexagonal BN flake. We
probe the Coulomb diamonds of the gate induced quantum dot exhibiting charging
energies of and orbital excitation energies up to
. The gate hysteresis for sweeps covering 5 Coulomb diamonds
reveals an energy hysteresis of only between upwards and
downwards sweeps. Charge noise is studied via long-term measurements at the
slope of a Coulomb peak revealing potential fluctuations of at 1\,Hz. This makes h-BN the dielectric with
the currently lowest gate hysteresis and lowest low-frequency potential
fluctuations reported for low-gap III-V nanowires. The extracted values are
similar to state-of-the art quantum dots within Si/SiGe and Si/SiO
systems
A Component-Based Middleware for a Reliable Distributed and Reconfigurable Spacecraft Onboard Computer
Emerging applications for space missions require increasing processing performance from the onboard computers. DLR's project “Onboard Computer - Next Generation” (OBC-NG) develops a distributed, reconfigurable computer architecture to provide increased performance while maintaining the high reliability of classical spacecraft computer architectures. Growing system complexity requires an advanced onboard middleware, handling distributed (realtime) applications and error mitigation by reconfiguration. The OBC-NG middleware follows the Component-Based Software Engineering (CBSE) approach. Using composite components, applications and management tasks can easily be distributed and relocated on the processing nodes of the network. Additionally, reuse of components for future missions is facilitated. This paper presents the flexible middleware architecture, the composite component framework, the middleware services and the model-driven Application Programming Interface (API) design of OBC-NG. Tests are conducted to validate the middleware concept and to investigate the reconfiguration efficiency as well as the reliability of the system. A relevant use case shows the advantages of CBSE for the development of distributed reconfigurable onboard software
A superspace module for the FeynRules package
We describe an additional module for the Mathematica package FeynRules that
allows for an easy building of any N=1 supersymmetric quantum field theory,
directly in superspace. After the superfield content of a specific model has
been implemented, the user can study the properties of the model, such as the
supersymmetric transformation laws of the associated Lagrangian, directly in
Mathematica. While the model dependent parts of the latter, i.e., the soft
supersymmetry-breaking Lagrangian and the superpotential, have to be provided
by the user, the model independent pieces, such as the gauge interaction terms,
are derived automatically. Using the strengths of the Feynrules program, it is
then possible to derive all the Feynman rules associated to the model and
implement them in all the Feynman diagram calculators interfaced to FeynRules
in a straightforward way.Comment: 54 pages, 9 tables, version accepted by CP
Segmental duplications are hot spots of copy number variants affecting barley gene content
Copy number variants (CNVs) are pervasive in several animal and plant genomes and contribute to shaping genetic diversity. In barley, there is evidence that changes in gene copy number underlie important agronomic traits. The recently released reference sequence of barley represents a valuable genomic resource for unveiling the incidence of CNVs that affect gene content and identifying sequence features associated with CNV formation. Using exome sequencing and read count data, we detected 16,605 deletions and duplications that affect barley gene content by surveying a diverse panel of 172 cultivars, 171 landraces, 22 wild relatives and other 32 uncategorized domesticated accessions. The quest for segmental duplications (SDs) in the reference sequence revealed many low-copy repeats, most of which overlap predicted coding sequences. Statistical analyses revealed that the incidence of CNVs increases significantly in SD-rich regions, indicating that these sequence elements act as hot spots for the formation of CNVs. This study delivers a comprehensive genome-wide study of CNVs affecting barley gene content and implicates SDs in the molecular mechanisms that lead to the formation of this class of CNVs
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Curcuminoid–BF2 complexes: Synthesis, fluorescence and optimization of BF2 group cleavage
Eight difluoroboron complexes of curcumin derivatives carrying alkyne groups containing substituents have been synthesized following an optimised reaction pathway. The complexes were received in yields up to 98% and high purities. Their properties as fluorescent dyes have been investigated. Furthermore, a strategy for the hydrolysis of the BF2 group has been established using aqueous methanol and sodium hydroxide or triethylamine
It takes three to tango: The length of the oligothiophene chain determines the nature of the long‐lived excited state and the resulting photocytotoxicity of a ruthenium(II) Photodrug
Abstract TLD1433 is the first Ru(II) complex to be tested as a photodynamic therapy agent in a clinical trial. In this contribution we study TLD1433 in the context of structurally‐related Ru(II)‐imidozo[4,5‐f][1,10]phenanthroline (ip) complexes appended with thiophene rings to decipher the unique photophysical properties which are associated with increasing oligothiophene chain length. Substitution of the ip ligand with ter‐ or quaterthiophene changes the nature of the long‐lived triplet state from metal‐to‐ligand charge‐transfer to 3 ππ* character. The addition of the third thiophene thus presents a critical juncture which not only determines the photophysics of the complex but most importantly its capacity for 1 O 2 generation and hence the potential of the complex to be used as a photocytotoxic agent
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