NOTEWORTHY BIRD RECORDS IN SONTECOMAPAN, VERACRUZ, MEXICO

Registramos observaciones sobresalientes de aves en el sur del estado de Veracruz. Se reporta la tercera localidad donde se ha registrado la polluela pechigris (Laterallu sexilis) para el país, el primer registro para el estado del rascón cuello rufo (Aramides axillaris), el segundo registro de colimbo mayor (Gavia immer) para el sur del estado, así como el registro de una pareja de hocofaisanes (Crax rubra) en el área de manglar de Sontecomapan

Application of multivariate statistical analysis to assess browning bsusceptibility in sweet potatoes (Ipomoea batatas (l.) Lam.) cultivars, based on chemical and enzymatic determinations

The selection of a sweet potato cultivar for minimal processing must be performed considering the nutritional value and the lower susceptibility to browning development, which will result in greater stability of the vegetable colour. The aim of this work was to evaluate browning susceptibility in four sections of two sweet potato cultivars combining chemical and enzymatic determinations with colour variables, by applying multivariate statistical techniques. Each cultivar had a characteristic browning pattern; in white cultivar colour changes were represented by changes in variable b* while in the red cultivar these changes responded to variations in variable a*.The regions with major colour changes (ΔE*>6) after 24 hours also had high levels of phenolic compounds (658±98 mg chlorogenic acid/kg fresh tissue) and high oxidative enzymes activities. Principal Component Analysis indicated that three regions in white cultivar and two in red cultivar had low browning susceptibility. Partial Least Square analysis indicated that colour changes (ΔE*) were highly associated with Polyphenoloxidase activity and phenolic compounds. By comparing both cultivars analyzed, the white cultivar presented 3 regions with low browning susceptibility and therefore would be more suitable for minimally processing. This low susceptibility would be related to low phenol content and lower enzyme activities.Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA)Facultad de Ciencias Agrarias y Forestales (FCAF

Application of multivariate statistical analysis to assess browning bsusceptibility in sweet potatoes (Ipomoea batatas (l.) Lam.) cultivars, based on chemical and enzymatic determinations

The selection of a sweet potato cultivar for minimal processing must be performed considering the nutritional value and the lower susceptibility to browning development, which will result in greater stability of the vegetable colour. The aim of this work was to evaluate browning susceptibility in four sections of two sweet potato cultivars combining chemical and enzymatic determinations with colour variables, by applying multivariate statistical techniques. Each cultivar had a characteristic browning pattern; in white cultivar colour changes were represented by changes in variable b* while in the red cultivar these changes responded to variations in variable a*.The regions with major colour changes (ΔE*>6) after 24 hours also had high levels of phenolic compounds (658±98 mg chlorogenic acid/kg fresh tissue) and high oxidative enzymes activities. Principal Component Analysis indicated that three regions in white cultivar and two in red cultivar had low browning susceptibility. Partial Least Square analysis indicated that colour changes (ΔE*) were highly associated with Polyphenoloxidase activity and phenolic compounds. By comparing both cultivars analyzed, the white cultivar presented 3 regions with low browning susceptibility and therefore would be more suitable for minimally processing. This low susceptibility would be related to low phenol content and lower enzyme activities.Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA)Facultad de Ciencias Agrarias y Forestales (FCAF

Synthesis of the contribution of the GiESCO (group of International Experts of vitivinicultural Systems for CoOperation) to the study of terroirs.

Since 1998, the GiESCO (previously named GESCO: Groupe d?Etude des Systèmes deCOnduite de la vigne) has provided the scientific community with relevant contributions tothe study of terroirs. Here is a synthesis of the main terroir-related fields and the major ideasthe GiESCO has developed: Basic Terroir Unit and climate, Vine Ecophysiology andmicroclimate ? moderate drought, Vineyard heterogeneity and new technologies, ViticulturalTerroir Unit and canopy management, Terroir ? Territory and man

Experimental approval of the extended flat bands and gapped subbands in rhombohedral multilayer graphene

Graphene layers are known to stack in two stable configurations, namely ABA or ABC stacking, with drastically distinct electronic properties. Unlike the ABA stacking, little has been done to experimentally investigate the electronic properties of ABC graphene multilayers. Here, we report the first magneto optical study of a large ABC domain in a graphene multilayers flake, with ABC sequences exceeding 17 graphene sheets. The ABC-stacked multilayers can be fingerprinted with a characteristic electronic Raman scattering response, which persists even at room temperatures. Tracing the magnetic field evolution of the inter Landau level excitations from this domain gives strong evidence to the existence of a dispersionless electronic band near the Fermi level, characteristic of such stacking. Our findings present a simple yet powerful approach to probe ABC stacking in graphene multilayer flakes, where this highly degenerated band appears as an appealing candidate to host strongly correlated states.Comment: 8 pages, 4 figure

Phonon assisted dynamical Coulomb blockade in a thin suspended graphite sheet

The differential conductance in a suspended few layered graphene sample is fou nd to exhibit a series of quasi-periodic sharp dips as a function of bias at l ow temperature. We show that they can be understood within a simple model of dyn amical Coulomb blockade where energy exchanges take place between the charge carriers transmitted trough the sample and a dissipative electromagnetic envir onment with a resonant phonon mode strongly coupled to the electrons

Effect of organic loading rate on the production of Polyhydroxyalkanoates from sewage sludge

The aim of this work was to study the effect of organic loading rate on the production of Polyhydroxyalkanoates (PHA) from sewage sludge. Synthesis of PHA using sewage sludge as platform was achieved in this work. Three pilot-scale selection-sequencing batch reactors (S-SBR) were used for obtaining a culture able to accumulate PHA following a strategy of aerobic dynamic feeding (ADF) at different volumetric organic-loading-rate (vOLR): 1.3, 1.8 and 0.8 g COD L-1 d-1 for S-SBR 1, S-SBR 2 and S-SBR 3, respectively. Decreasing the vOLR enhanced the general performance of the process as for organic matter removal (from 99.2% ± 0.3% in S-SBR-3 to 92 ± 2 in S-SBR-2) while the opposite trend was recorded for PHA production (6.0 PHA % w/w in S-SBR-3 vs 13.7 PHA % w/w in S-SBR-2 at the end of the feast phase). Furthermore, indirect and direct emissions, as N2O, were evaluated during the process for the first time. Finally, three accumulation tests were performed achieving 24% w/w

M-Dwarf Fast Rotators and the Detection of Relatively Young Multiple M-Star Systems

We have searched the Kepler light curves of ~3900 M-star targets for evidence of periodicities that indicate, by means of the effects of starspots, rapid stellar rotation. Several analysis techniques, including Fourier transforms, inspection of folded light curves, 'sonograms', and phase tracking of individual modulation cycles, were applied in order to distinguish the periodicities due to rapid rotation from those due to stellar pulsations, eclipsing binaries, or transiting planets. We find 178 Kepler M-star targets with rotation periods, P_rot, of < 2 days, and 110 with P_rot < 1 day. Some 30 of the 178 systems exhibit two or more independent short periods within the same Kepler photometric aperture, while several have three or more short periods. Adaptive optics imaging and modeling of the Kepler pixel response function for a subset of our sample support the conclusion that the targets with multiple periods are highly likely to be relatively young physical binary, triple, and even quadruple M star systems. We explore in detail the one object with four incommensurate periods all less than 1.2 days, and show that two of the periods arise from one of a close pair of stars, while the other two arise from the second star, which itself is probably a visual binary. If most of these M-star systems with multiple periods turn out to be bound M stars, this could prove a valuable way of discovering young hierarchical M-star systems; the same approach may also be applicable to G and K stars. The ~5% occurrence rate of rapid rotation among the ~3900 M star targets is consistent with spin evolution models that include an initial contraction phase followed by magnetic braking, wherein a typical M star can spend several hundred Myr before spinning down to periods longer than 2 days.Comment: 17 pages, 12 figures, 2 tables; accepted for publication in The Astrophysical Journa