Horizons: Nuclear Astrophysics in the 2020s and Beyond

Nuclear Astrophysics is a field at the intersection of nuclear physics and astrophysics, which seeks to understand the nuclear engines of astronomical objects and the origin of the chemical elements. This white paper summarizes progress and status of the field, the new open questions that have emerged, and the tremendous scientific opportunities that have opened up with major advances in capabilities across an ever growing number of disciplines and subfields that need to be integrated. We take a holistic view of the field discussing the unique challenges and opportunities in nuclear astrophysics in regards to science, diversity, education, and the interdisciplinarity and breadth of the field. Clearly nuclear astrophysics is a dynamic field with a bright future that is entering a new era of discovery opportunities.Comment: 96 pages. Submitted to Journal of Physics

Horizons: nuclear astrophysics in the 2020s and beyond

Nuclear astrophysics is a field at the intersection of nuclear physics and astrophysics, which seeks to understand the nuclear engines of astronomical objects and the origin of the chemical elements. This white paper summarizes progress and status of the field, the new open questions that have emerged, and the tremendous scientific opportunities that have opened up with major advances in capabilities across an ever growing number of disciplines and subfields that need to be integrated. We take a holistic view of the field discussing the unique challenges and opportunities in nuclear astrophysics in regards to science, diversity, education, and the interdisciplinarity and breadth of the field. Clearly nuclear astrophysics is a dynamic field with a bright future that is entering a new era of discovery opportunities

Natural metabolites for parasitic weed management

Compounds of natural origin, such as phytotoxins produced by fungi or natural amino acids, could be used in parasitic weed management strategies by interfering with the early growth stages of the parasites. These metabolites could inhibit seed germination or germ tube elongation, so preventing attachment to the host plant, or, conversely, stimulate seed germination in the absence of the host, contributing to a reduction in the parasite seed bank. Some of the fungal metabolites assayed were very active even at very low concentrations, such as some macrocyclic trichothecenes,which at 0.1 ??M strongly suppressed the germination of Orobanche ramosa L. seeds. Interesting resultswere also obtainedwith somenovel toxins, such as phyllostictine A, highly active in reducing germ tube elongation and seed germination both of O. ramosa and of Cuscuta campestris Yuncker. Among the amino acids tested, methionine and arginine were particularly interesting, as they were able to suppress seed germination at concentrations lower than 1mM. Some of the fungal metabolites tested were also able to stimulate the germination of O. ramosa seed

Stoechanones A and B, Phytotoxic Copaane Sesquiterpenoids Isolated from Lavandula stoechas with Potential Herbicidal Activity against Amaranthus retroflexus

From the organic extract of Lavandula stoechas, a Mediterranean native plant species, two new phytotoxic copaane sesquiterpenoids were isolated and named stoechanones A and B (1 and 2). They were obtained together with the methyl esters of caffeic and p-coumaric acids and the flavonoid apigenin (3-5, respectively). The structures of stoechanones A and B were determined by spectroscopic (essentially 1D and 2D 1H and 13C NMR and HRESIMS) and chemical methods, and they were characterized as 9,10-dihydroxy-8-isopropyl-1,5-dimethyltricyclo[4.4.0.02.7]dec-4-en-3-one and its 9-O-acetyl derivative. Their relative configurations were assigned by NOESY experiments, and the absolute configurations by comparison of the experimental and DFT-computed ECD spectra. When assayed through Petri dish bioassays, both stoechanones A and B showed phytotoxic effects against seed germination and seedling growth of Amaranthus retroflexus, strongly inhibiting seed germination percentage and radicle and hypocotyl lengths of seedlings. Owing to the herbicidal activity toward A. retroflexus, these two new tricyclic sesquiterpenoids could be proposed and developed as natural bioherbicides in order to increase the control of this problematic weed in the future

Inuloxins A???D, phytotoxic bi-and tri-cyclic sesquiterpene lactones produced by Inula viscosa: Potential for broomrapes and field dodder management

Four phytotoxic bi- and tri-cyclic sesquiterpene lactones, named inuloxins A???D, were isolated together with the known a-costic acid, from the aerial parts of Inula viscosa (family Asteraceae), a widespread Mediterranean plant well known for its content of pharmacologically active metabolites. The structures of inuloxins A???D were established by spectroscopic and chemical methods and determined to be: (4E,7R*,8R*,10S*)-3-oxo-germacra-4,11(13)-dien-8b-12-olide (A), its 11,13-dihydro analogue (B), (5*, 7R*,8R*,10R*)-1,15-methylene-5b-hydroxy-eudesm-1(15),11(13)-dien-8b-12-olide (C), and (7R*,8R*)-1,4-dimethyl-4-hydroxy-secoeudesm-5(10),11(13)-dien-8b-12-olide (D). The S absolute stereochemistry at C-5 of 5-hydroxyhexan-2-yl side chain of inuloxin D was assigned by applying an advanced Mosher???s method. The phytotoxic activity of inuloxins A???D, that of the diazo and monoacetyl derivatives (of inuloxin A and C, respectively), as well as that of a-costic acid was evaluated against two parasitic plant species, i.e. crenate broomrape (Orobanche crenata) and field dodder (Cuscuta campestris). Inuloxins A, C and D were the most active on both parasites and caused up to 100% inhibition of the seed germination. Inuloxin B was less active on Cuscuta and completely inactive against Orobanche. The main metabolite a-costic acid had a suppressive effect on the dodder seed germination but had a stimulating action on the broomrape seed germination. These preliminary results allowed to suppose some structure???activity relationships

Horizons: nuclear astrophysics in the 2020s and beyond

Nuclear astrophysics is a field at the intersection of nuclear physics and astrophysics, which seeks to understand the nuclear engines of astronomical objects and the origin of the chemical elements. This white paper summarizes progress and status of the field, the new open questions that have emerged, and the tremendous scientific opportunities that have opened up with major advances in capabilities across an ever growing number of disciplines and subfields that need to be integrated. We take a holistic view of the field discussing the unique challenges and opportunities in nuclear astrophysics in regards to science, diversity, education, and the interdisciplinarity and breadth of the field. Clearly nuclear astrophysics is a dynamic field with a bright future that is entering a new era of discovery opportunities

Horizons : nuclear astrophysics in the 2020s and beyond

Nuclear astrophysics is a field at the intersection of nuclear physics and astrophysics, which seeks to understand the nuclear engines of astronomical objects and the origin of the chemical elements. This white paper summarizes progress and status of the field, the new open questions that have emerged, and the tremendous scientific opportunities that have opened up with major advances in capabilities across an ever growing number of disciplines and subfields that need to be integrated. We take a holistic view of the field discussing the unique challenges and opportunities in nuclear astrophysics in regards to science, diversity, education, and the interdisciplinarity and breadth of the field. Clearly nuclear astrophysics is a dynamic field with a bright future that is entering a new era of discovery opportunities.peerReviewe