Shape Function Effects in B -> X_c l \nu_l

Owing to the fact that m_c^2 ~ m_b \Lambda_QCD, the endpoint region of the charged lepton energy spectrum in the inclusive decay B -> X_c l \nu_l is affected by the Fermi motion of the initial-state b quark bound in the B meson. This effect is described in QCD by shape functions. Including the mass of the final-state quark, we find that a different set of operators as employed in Ref. hep-ph/0205150 is needed for a consistent matching, when incorporating the subleading contributions in B -> X_q l \nu_l for both q = u and q = c. In addition, we modify the usual twist expansion in such a way that it yields a description of the lepton energy spectrum which is not just valid in the endpoint region, but over the entire phase space.Comment: 8 Pages, LaTeX, 2 figures; a few typos corrected and some clarifications added, final journal versio

On the nature of the AGILE galactic transient sources

The Italian gamma-ray satellite AGILE has recently reported the detection of some variable high-energy sources likely of galactic origin. These sources do not have any obvious counterpart at lower energies. We propose that these sources are produced in proton-dominated jets of galactic microquasars. We develop a model for microquasar jets that takes into account both primary leptons and protons and all relevant radiative processes, including secondary particle emission and gamma-ray attenuation due to pair creation in the jet. We obtain spectral energy distributions that correspond to what is observed by AGILE, with most of the power concentrated between 100 MeV and 10 GeV and reaching luminosities of $10^{34-35}$ erg s$^{-1}$. We make detailed spectral predictions that can be tested by the Fermi gamma-ray telescope in the immediate future. We conclude that hadronic jets in galactic accreting sources can be responsible for the variable unidentified gamma-ray sources detected by AGILE.Comment: 4 pages, 2 figures. Accepted for publication in Astronomy & Astrophysics (Letters

Relative Riemann-Zariski spaces

In this paper we study relative Riemann-Zariski spaces attached to a morphism of schemes and generalizing the classical Riemann-Zariski space of a field. We prove that similarly to the classical RZ spaces, the relative ones can be described either as projective limits of schemes in the category of locally ringed spaces or as certain spaces of valuations. We apply these spaces to prove the following two new results: a strong version of stable modification theorem for relative curves; a decomposition theorem which asserts that any separated morphism between quasi-compact and quasi-separated schemes factors as a composition of an affine morphism and a proper morphism. (In particular, we obtain a new proof of Nagata's compactification theorem.)Comment: 30 pages, the final version, to appear in Israel J. of Mat

Private military and security contractors: a face-off with the notion of direct participation in hostilities, in international armed conflicts

Private military and security companies (PMSCs) have become a significant feature in recent international armed conflicts. Under international humanitarian law, PMSCs are, for the most part, clothed with civilian status. As civilians, they are precluded from any direct participation in hostilities if they are to ensure their immunity against direct targeting, and yet they are increasingly performing duties once reserved for military personnel. This article analyses the functions traditionally undertaken by PMSCs in light of the International Committee of the Red Cross’s (ICRC) interpretation of what constitutes unlawful direct participation in hostilities. This analysis offers advice to PMSCs, and those opposing them, as to what activities might compromise their civilian immunity against attack. This article also explores the legal consequences which result when PMSCs elect to participate directly in hostilities, despite their civilian status

Israel attacks an ‘aid’ flotilla bound for Gaza: A dark day for international law

This paper examines the Israeli raid on six aid vessels bound for Gaza on 31 May 2010, in light of customary International Humanitarian Law (IHL). In exploring the international law implications of these events, the concepts of a legal maritime blockade and the use of force to impose such a blockade are unpacked. The article considers whether the use of force by the civilians on board the vessels amounted to ‘direct participation in hostilities’, and whether either side might have a legitimate claim to have acted in self-defence. Lastly, the obligations placed upon belligerents when they detain civilians are examined, in light of the fundamental guarantees of humane treatment enshrined in IHL

Photoinduced Coupling of Acetylenes and Quinone in the Solid State as Preorganized Donor−Acceptor Pairs

Crystalline electron donor−acceptor (EDA) complexes of various diarylacetylenes (DA) and dichlorobenzoquinone (DB) are isolated and structurally characterized by X-ray crystallography. Deliberate excitation of either the DB acceptor at λDB = 355 nm or the 1:2 [DA, 2DB] complex at λCT = 532 nm in the solid state leads to [2 + 2] cycloaddition and identical (isomeric) mixtures of the quinone methide products. Time-resolved (ps) diffuse reflectance spectroscopy identifies the ion-radical pair [DA•+, DB•-] as the reactive intermediate derived by photoinduced electron transfer in both photochemical procedures. The effects of crystal-lattice control on the subsequent ion-radical pair dynamics are discussed in comparison with the same photocouplings of acetylenes and quinone previously carried out in solution

Marinas as habitats for nearshore fish assemblages: comparative analysis of underwater visual census, baited cameras and fish traps

Understanding the ecological role that artificial structures might play on nearshore fish assemblages requires the collection of accurate and reliable data through efficient sampling techniques. In this work, differences in the composition and structure of fish assemblages between the inner and outer sides of three marinas located in the temperate northern-eastern Atlantic Ocean were tested using three complementary sampling techniques: underwater visual censuses (UVC), baited cameras (BCs) and fish traps (FTs). UVCs and BCs recorded a comparable number and relative abundance of species, which in turn were much greater than those recorded by FTs. This finding supports the use of UVCs and BCs over FTs for broad ecologically studies, especially when dealing with structurally complex habitats such as artificial structures. We found differences in fish assemblage structure between the inner and outer sides of marinas, independently of the sampling method. Four small-sized species (Similiparma lurida, Thalassoma pavo, Sarpa salpa and Symphodus roissali) associated with structurally complex vegetated habitats dominated, in terms of abundance, the outer sides of marinas; Diplodus vulgaris, Diplodus sargus and Gobius niger, species with high ecological plasticity in habitat requirements, dominated the inner sides of marinas. The information provided in this study is of great interest for developing sound monitoring programmes to ascertain the effects of artificial structures on fish communities.info:eu-repo/semantics/publishedVersio

Preservation and Dissolution of the Target Firm's Embedded Ties in Acquisitions

Our study builds on extant theory on embeddness to concentrate on the process of preservation and dissolution of the target firm’s embedded ties in acquisitions. We identify four critical areas - communication, idiosyncratic investments, inter-personal relations and, personnel turnover – where managerial decisions taken during the acquisition process affect the components of the target firm’s embedded ties – trust, joint problem-solving and exchange of fine-grained information. The preservation or dissolution of an embedded tie depends ultimately on two specific tie-contingencies, the balance of power between the target firm and the embedded relation and interpretive processes at the inter-face between the two. Our findings have implications for the study of the dissolution of market ties as they point to different roles played by social and institutional forces, power asymmetries and competition in the dynamics of embedded ones. Finally, we encourage theory development in acquisition studies by positing the importance of interpretive processes and, more broadly, relational elements that span the boundaries of the parent-target dyad.Acquisitions;Embedded tie dynamics;Embedded ties