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The structure and energetics of the ring isomers of C(4n+2) (n=3-5) carbon clusters were studied by using coupled-cluster singles and doubles excitation theory to overcome the vast differences existing in the literature. The results obtained in the present study clearly indicate that C₁₄, C₁₈, and C₂₂ carbon rings have bond-length and bond-angle alternated acetylenic minimum energy structures. Contrarily, density functional theory calculations were unable to predict these acetylenic-type structures and they ended up with the cumulenic structures. It is found from the coupled-cluster studies that the lowest-energy ring isomer for the first two members of C(4n+2) series is a bond-angle alternated cumulenic D((2n+1)h) symmetry structure while the same for the remaining members is a bond-length and bond-angle alternated C((2n+1)h) symmetry structure. In C(4n+2) carbon rings, Peierls-type distortion, transformation from bond-angle alternated to bond-length alternated minimum energy structures, occurs at C₁₄ carbon ring. ; This study was supported by the RSS21 project and a Grant-in-Aid for Scientific Research No. 17064017 of MEXT, Government of Japan.

The structure and energetics of the ring isomers of C(4n+2) (n=3-5) carbon clusters were studied by using coupled-cluster singles and doubles excitation theory to overcome the vast differences existing in the literature. The results obtained in the present study clearly indicate that C₁₄, C₁₈, and C₂₂ carbon rings have bond-length and bond-angle alternated acetylenic minimum energy structures. Contrarily, density functional theory calculations were unable to predict these acetylenic-type structures and they ended up with the cumulenic structures. It is found from the coupled-cluster studies that the lowest-energy ring isomer for the first two members of C(4n+2) series is a bond-angle alternated cumulenic D((2n+1)h) symmetry structure while the same for the remaining members is a bond-length and bond-angle alternated C((2n+1)h) symmetry structure. In C(4n+2) carbon rings, Peierls-type distortion, transformation from bond-angle alternated to bond-length alternated minimum energy structures, occurs at C₁₄ carbon ring. ; This study was supported by the RSS21 project and a Grant-in-Aid for Scientific Research No. 17064017 of MEXT, Government of Japan.

Transport modeling is a tool to evaluate the consequences of infrastructure projects, to compute the traffic volumes and to predict changes in traffic flows, modal shares and possible bottlenecks in the transport network.

National transport modeling includes creating base models, to be adapted depending on the usage. The accuracy of base models depends on the national needs. Local, cantonal, regional and urban models are complementary to national transport models and allow differentiated approaches according to territorial specificities.

In collaboration with the Federal Office of Transport FOT and the Federal Roads Office FEDRO, the Federal Office for Spatial Development ARE has created a multimodal base model for passenger traffic for rail and road. Similarly, a national model for goods has recently been created and an aggregate method for freight has been developed.

More: www.are.admin.ch/vm-uvek

Transport modeling is a tool to evaluate the consequences of infrastructure projects, to compute the traffic volumes and to predict changes in traffic flows, modal shares and possible bottlenecks in the transport network.

National transport modeling includes creating base models, to be adapted depending on the usage. The accuracy of base models depends on the national needs. Local, cantonal, regional and urban models are complementary to national transport models and allow differentiated approaches according to territorial specificities.

In collaboration with the Federal Office of Transport FOT and the Federal Roads Office FEDRO, the Federal Office for Spatial Development ARE has created a multimodal base model for passenger traffic for rail and road. Similarly, a national model for goods has recently been created and an aggregate method for freight has been developed.

More: www.are.admin.ch/vm-uvek

International audience ; Political attention has increasingly focused on limiting warming to 2°C. However, there is no consensus on both questions "Is the 2°C target achievable?" and "What should be done with this target that becomes increasingly difficult to achieve?". This paper aims at disentangling the points of deep uncertainty underlying this absence on consensus. It first gives simple visualizations of the challenge posed by the 2°C target and shows how key assumptions (on the points of deep uncertainty) influence the answer to the target achievability question. It then proposes an "uncertainties and decisions tree", linking different beliefs on climate change, the achievability of different policies, and current international policy dynamics to various options to move forward on climate change.

International audience ; Political attention has increasingly focused on limiting warming to 2°C. However, there is no consensus on both questions "Is the 2°C target achievable?" and "What should be done with this target that becomes increasingly difficult to achieve?". This paper aims at disentangling the points of deep uncertainty underlying this absence on consensus. It first gives simple visualizations of the challenge posed by the 2°C target and shows how key assumptions (on the points of deep uncertainty) influence the answer to the target achievability question. It then proposes an "uncertainties and decisions tree", linking different beliefs on climate change, the achievability of different policies, and current international policy dynamics to various options to move forward on climate change.

International audience ; Political attention has increasingly focused on limiting warming to 2°C. However, there is no consensus on both questions "Is the 2°C target achievable?" and "What should be done with this target that becomes increasingly difficult to achieve?". This paper aims at disentangling the points of deep uncertainty underlying this absence on consensus. It first gives simple visualizations of the challenge posed by the 2°C target and shows how key assumptions (on the points of deep uncertainty) influence the answer to the target achievability question. It then proposes an "uncertainties and decisions tree", linking different beliefs on climate change, the achievability of different policies, and current international policy dynamics to various options to move forward on climate change.

International audience ; Political attention has increasingly focused on limiting warming to 2°C. However, there is no consensus on both questions "Is the 2°C target achievable?" and "What should be done with this target that becomes increasingly difficult to achieve?". This paper aims at disentangling the points of deep uncertainty underlying this absence on consensus. It first gives simple visualizations of the challenge posed by the 2°C target and shows how key assumptions (on the points of deep uncertainty) influence the answer to the target achievability question. It then proposes an "uncertainties and decisions tree", linking different beliefs on climate change, the achievability of different policies, and current international policy dynamics to various options to move forward on climate change.