Reconsidering extra time-like dimensions

In this study we reconsider the phenomenological problems related to tachyonic modes in the context of extra time-like dimensions. First we reconsider a lower bound on the size of extra time-like dimensions. Next we discuss the issues of spontaneous decay of stable fermions through tachyonic decays and disappearance of fermions due to tachyonic contributions to their self-energies. We find that the tachyonic modes due to extra time-like dimensions are less problematic than the tachyonic modes in the usual 4-dimensional setting because the most troublesome Feynman diagrams are forbidden once the conservation of momentum in the extra time-like dimensions is imposed.Comment: The version to appear in EPJ

New Production Mechanism for Heavy Neutrinos at the LHC

We study a new production mechanism for heavy neutrinos at the LHC, which dominates over the usually considered $s$-channel $W$-exchange diagram for heavy-neutrino masses larger than 100 - 200 GeV. The new mechanism is infrared-enhanced by $t$-channel $W\gamma$-fusion processes. This has important implications for experimental tests of the seesaw mechanism of neutrino masses, and in particular, for the ongoing heavy neutrino searches at the LHC. We find that the direct collider limits on the light-to-heavy neutrino mixing can be significantly improved, when this new production channel is properly taken into account. The scope of this new mechanism can equally well be extended to other exotic searches at the LHC.Comment: 5 pages, 4 figures; version accepted by Phys. Rev. Let

Emerging evidence of superior performance in laparoscopic combined hepatectomy and colectomy

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The range of axial rotation of the glenohumeral joint.

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Aquatic agricultural systems in Cambodia: national situation analysis

The objective of the current report produced for the CGIAR Research Program on Aquatic Agricultural Systems (AAS) is to provide basic information on key constraints driving poverty and vulnerability in aquatic agricultural systems in the Tonle Sap region in Cambodia. Six objectives and corresponding research themes are included in the program: sustainable increases in productivity; equitable access to markets; resilience and adaptive capacity; empowering policies and institutions; reduced gender disparity; and expanded benefits for the resource-poor. In this report, the authors review the main aquatic agricultural systems (status, specific policies and strategies, interventions, challenges, and options), then review the main drivers of change. This leads to an identification of plans and strategies important to AAS, with a particular focus on perspectives, gaps and opportunities in national policies, community engagement, increased benefits, adaptive capacity, and gender. This review, of potential interest to decision makers and all development partners, leads to conclusions and recommendations aimed at policymakers and institutional as well as private investors in development

Naturalness and Dark Matter Properties of the BLSSM

In this report, we compare the naturalness and Dark Matter (DM) properties of the Minimal Supersymmetric Standard Model (MSSM) and the $B-L$ Supersymmetric Standard Model (BLSSM), with universality in both cases. We do this by adopting standard measures for the quantitative analysis of the Fine-Tuning (FT), at both low (i.e. supersymmetric (SUSY)) and high (i.e. unification) scales. We will see a similar level of FT for both models in these scenarios, with a slightly better FT for the BLSSM at SUSY scales and MSSM at Grand Unification Theory (GUT) scales. When including DM relic constraints, we drastically confine the MSSM's parameter space, whereas we still find a large parameter space available for the non-minimal scenario.Comment: Prepared for proceedings for DIS2017, talk presented by Simon Kin

Public health emergencies: a new peacekeeping mission? Insights from UNMIL’s role in the Liberia Ebola outbreak

The UN Security Council meeting on 18 September 2014 represented a major turning-point in the international response to the Ebola outbreak then underway in West Africa. However, in the light of widespread criticism over the tardiness of the international response, it can be argued that the UN, and particularly the Security Council, failed to make best use of a potential resource it already had on the ground in Liberia: the United Nations Mission in Liberia (UNMIL). This article examines whether UNMIL could have done more to contribute to the emergency response and attempts to draw some lessons from this experience for potential peacekeeper involvement in future public health emergencies. UNMIL could have done more than it did within the terms of its mandate, although it may well have been hampered by factors such as its own capacities, the views of Troop Contributing Countries and the approach taken by the Liberian government. This case can inform broader discussions over the provision of medical and other forms of humanitarian assistance by peacekeeping missions, such as the danger of politicising humanitarian aid and peacekeepers doing more harm than good. Finally, we warn that a reliance on peacekeepers to deliver health services during ‘normal’ times could foster a dangerous culture of dependency, hampering emergency responses if the need arises

Prospects for Sneutrino Dark Matter in the BLSSM

The $(B-L)$ Supersymmetric Standard Model (BLSSM) motivates several Dark Matter (DM) candidates beyond the Minimally Supersymmetric Standard Model (MSSM). We assess the comparative naturalness of the two models and discuss the potential detection properties of a particular candidate, the Right-Handed (RH) sneutrino.Comment: Prepared for proceedings for La Thuile 2018, talk by Simon Kin