Short-term,linear, and non-linear local effects of the tides on the surface dynamics in a new,high-resolution model of the Mediterranean Sea circulation     

Palma  Massimiliano  Iacono  Roberto  Sannino  Gianmaria  Bargagli  Andrea  Carillo  Adriana  Fekete  Balazs M.  Lombardi  Emanuele  Napolitano  Ernesto  Pisacane  Giovanna  Struglia  Maria Vittoria 《Ocean Dynamics》2020,70(7):935-963

Ocean Dynamics - The tides in the Mediterranean Sea are generally weaker than in other regions of the world ocean, but are locally intensified in passages with complex bathymetry, such as the...  相似文献   

Grazing Management Plans improve pasture selection by cattle and forage quality in sub-alpine and alpine grasslands     

Marco PITTARELLO  Massimiliano PROBO  Elisa PEROTTI  Michele LONATI  Giampiero LOMBARDI  Simone RAVETTO ENRI 《山地科学学报》2019,(9)

Over the last decades, the reduction of manpower for herd management has led to an increase of continuous grazing systems(CGS) in the Italian Alps, which allow cattle to roam freely. Under CGS, due to high selectivity, livestock exploit grasslands unevenly, over-and under-using specific areas at the same time with negative effects on their conservation. To counteract these effects, a specific policy and management tool(i.e. Grazing Management Plan) has been implemented by Piedmont Region since 2010. The Grazing Management Plans are based on the implementation of rotational grazing systems(RGS), with animal stocking rate adjusted to balance it with grassland carrying capacity. A case study was conducted on alpine summer pastures to test the 5-year effects produced by the implementation of a Grazing Management Plan in grasslands formerly managed under several years of CGS on 1) the selection for different vegetation communities by cattle, 2) the abundance of oligo-, meso-, and eutrophic plant species(defined according to Landolt N indicator value), and 3) forage yield, quality, and palatability. A total of 193 vegetation surveys were carried out in 2011 and repeated in 2016. Cows were tracked yearly with Global Positioning System collars to assess their grazing selectivity, and forage Pastoral Value(PV) was computed to evaluate forage yield, quality, and palatability. Five years after RGS implementation, cow selectivity significantly decreased and the preference for the different vegetation communities was more balanced than under CGS. The abundance of meso-and eutrophic species increased, whereas oligotrophic ones decreased. Moreover, the abundance of moderately to highly palatable plant species increased, whereas non-palatable plant species decreased, with a consequent significant enhancement of the PV. Our findings indicate that the implementation of Grazing Management Plans can be considered a sustainable and effective management tool for improving pasture selection by cattle and forage quality in mountain pastures.  相似文献   

A detrital apatite fission‐track study of the CIROS‐2 sedimentary record: Tracing ice pathways in the Ross Sea area over the last 5 Ma     

Xia Li  Massimiliano Zattin  Valerio Olivetti 《地学学报》2019,31(3):271-280

The Ross Sea is a crucial area to investigate pathways of ice during the Cenozoic as it records the evolution of both the East and West Antarctic Ice Sheets. This work is based on detrital apatite fission track (AFT) data extracted from the sedimentary record of well CIROS‐2, which spans the last 5 Ma. The AFT data show a large range of ages, and most of the grains fit well with two main components that fall between 24 and 42 Ma and between 43 and 70 Ma, whereas the other components are not regularly distributed through the well, thus indicating a mixture of provenance from different areas along the Transantarctic Mountains. As a whole, our work suggests glacial expansion over the McMurdo Sound during the Pliocene, and ice periodically invading and retreating in Pleistocene.  相似文献   

A numerical study of the stabilization effect of steepness     

Nataša Todorović  Massimiliano Guzzo  Elena Lega  Claude Froeschlé 《Celestial Mechanics and Dynamical Astronomy》2011,110(4):389-398

We present the results of numerical experiments about the influence of steepness on the resonant structure, stability and diffusion in a 4-dimensional symplectic map. The map is designed so that by changing a parameter, we smoothly switch steepness on and off by the change of the so called steepness coefficients. In both cases we measure the diffusion coefficients of the actions within a resonance. According to Nekhoroshev theorem we find that, in the steep case, the diffusion coefficients are definitely smaller than in the non steep one, thus confirming the threshold effect of the steepness coefficients which comes from the proof of Nekhoroshev theorem.  相似文献   

Late Cenozoic orogenic history of Western Qinling inferred from sedimentation of Tianshui basin, northeastern margin of Tibetan Plateau   总被引：1，自引：0，他引：1  

Xiuxi Wang  Jijun Li  Chunhui Song  Massimiliano Zattin  Zhijun Zhao  Jun Zhang  Yong Zhang  Kuang He 《International Journal of Earth Sciences》2012,101(5):1345-1356

The Western Qinling orogenic belt marks the northeastern margin of the Tibetan Plateau. Its late Cenozoic orogenic history is recorded in an excellent sedimentary sequence exposed in the Tianshui sub-basin of the Longzhong basin. According to the magnetostratigraphic analysis from the Yaodian and Lamashan sections, we speculate that the late Cenozoic Tianshui basin accumulated lacustrine/floodplain deposits from ~14.8 to ~2.6?Ma. In addition, detrital apatite fission-track thermochronologic and paleocurrent data reveal that the detritus of the Tianshui basin mostly derived from the Western Qinling and that the youngest population age represents a ~14?Ma volcanic intrusion, which can be related to the lithospheric deformation and uplift of the Tibetan Plateau. Furthermore, two stages of variations in depositional facies and average accumulation rates were attributed to the pulse uplift and deformation of the Western Qinling at 9.2–7.4 and ~3.6?Ma.  相似文献