Biocatalytic Route to Chiral Precursors of β-Substituted-γ-Amino Acids

In this work, we utilized commercial lipases (from Thermomyces lanuginosa, Rhizopus delemar, and Mucor miehei) as biocatalysts for the efficient synthesis of precursors of β-substituted-γ-amino acids. This biocatalytic route provides a practical and efficient synthesis of a wide range of optically active compounds by accepting a number of aliphatic and aromatic 3-substituted-3-cyano-2-(ethoxycarbonyl)propanoic acid ethyl esters (2) without compromising enantioselectivity or yields. The resolution step allows for the nearly quantitative recovery of the unreacted enantiomer of R-(2) as well as the newly formed 3-substituted-3-cyano-2-(ethoxycarbonyl)propanoic acid (3) in high enantio and diastereoselectivity. The use of a facile thermal decarboxylation of (3) in aqueous solution to produce 3-substituted-3-cyanopropanoic acid ethyl esters (4) enable us to prepare a wide range of optically active precursors of β-Substituted-γ-Amino Acids

Coherence and broadening effects in medium induced gluon radiation

Interferences between different emitters in the multi-parton shower is the building block of QCD jet physics in vacuum. The presence of a hot medium made of quarks and gluons is expected to alter this interference pattern. To study such effects, we derive the gluon emission spectrum off an "asymptotic quark" traversing a hot and dense QCD medium at first order in the medium density. The resulting induced gluon distribution gets modified when the new interference terms between the initial and final quark are included. We comment on the possible phenomenological consequences of this new contribution for jet observables in heavy-ion collisions.Comment: 4 pages. To appear in the Proceedings of the conference Hard Probes 2012 - Sardinia - Italy - May 27 -June 1 201

Coherence phenomena between initial and final state radiation in a dense QCD medium

In this work we investigate medium modifications to the interference pattern between initial and final state radiation. We compute single gluon production off a highly energetic parton that undergoes a hard scattering and subsequently crosses a dense QCD medium of finite size. We extend our previous studies obtained at first order in opacity by providing general results for multiple soft scatterings and their specific formulation within the harmonic oscillator approximation. We show that there is a gradual onset of decoherence between the initial and final state radiation due to multiple scatterings, that opens the phase space for large angle emissions. By examining the multiplicity of produced gluons, we observe a potentially large double logarithmic enhancement for dense media and small opening angles. This result points to a possible modification of the evolution equations due to a QCD medium of finite size. We briefly comment on the phenomenological consequences of this setup in high-energy nuclear collisions.Comment: 33 pages, 2 figures. Fix typos and updated references. Discussion in the introduction updated. Accepted for publication in JHE

Power system stability of a small sized isolated network supplied by a combined wind-pumped storage generation system: a case study in the Canary Islands

Massive integration of renewable energy sources in electrical power systems of remote islands is a subject of current interest. The increasing cost of fossil fuels, transport costs to isolated sites and environmental concerns constitute a serious drawback to the use of conventional fossil fuel plants. In a weak electrical grid, as it is typical on an island, if a large amount of conventional generation is substituted by renewable energy sources, power system safety and stability can be compromised, in the case of large grid disturbances. In this work, a model for transient stability analysis of an isolated electrical grid exclusively fed from a combination of renewable energy sources has been studied. This new generation model will be installed in El Hierro Island, in Spain. Additionally, an operation strategy to coordinate the generation units (wind, hydro) is also established. Attention is given to the assessment of inertial energy and reactive current to guarantee power system stability against large disturbances. The effectiveness of the proposed strategy is shown by means of simulation results

PRODUCTION OF RUNT DISEASE IN TOLERANT MICE BY THE INJECTION OF SYNGENEIC LYMPHOID CELLS

When chimeric A strain mice tolerant of (A x C57BL/1)F1 hybrid skin grafts are injected with spleen cells from normal A donors the recipients develop weight loss, clinical evidence of runting, and death in some animals. Similar recipients injected with spleen cells from A strain donors immunized against C57BL/1 tissue show a more rapid onset of the runting process and increased mortality. Runting in. these experiments therefore results from an immune attack by the injected A strain lymphoid cells against the (A x C57BL/1)F1 hybrid tissue harbored by the chimeric recipients. Since the hybrid tissues of the chimeric recipients were derived from spleen cell populations we conclude that the immunologic rejection of lymphoid and hematopoietic tissue is sufficient to cause the runting syndrome. C3H mice tolerant of A strain skin grafts because of the prior injection of viable or disrupted A strain spleen material were given 400 r of x-irradiation and an injection of C3H spleen cells. Only the chimeric C3H mice harboring viable A strain cells developed weight loss and clinical evidence of disease, showing again that runting occurs only when an attack can be made against viable lymphoid and hematopoietic tissue. Normal A strain mice injected intravenously with 850 million (A x C57BL/1)F1 hybrid spleen cells reject hybrid skin grafts and do not develop runting, whereas the rejection of similar hybrid tissue present in chimeric A strain mice results in runting. It is concluded that runting will occur only when the immunologic attack is directed against lymphoid and hematopoietic tissue which has become established within host tissues. The possibility that runting may result from hypersensitivity reactions occurring in the lymphoid tissues is discussed

Video tracking of dairy cows for assessing mobility scores

Lameness afflicts a large proportion of dairy herds, but could be considerably reduced by automated monitoring by CCTV. Key to this is reliable, robust detection and tracking of individual cows in crowded video sequences. We introduce a novel detection and tracking method, based on the Viola-Jones detector. We show that animals can be tracked and their overall gait patterns and speed automatically extracted from video sequences. Preliminary work on identification of individual animals through principal component analysis and SIFT feature matching is also described