1,353 research outputs found
Ciclo biológico da cochonilha negra, Saissetia oleae (Olivier), em oliveira, na Terra Quente Transmontana.
Originária, segundo se admite, da África do Sul, e tendo como principal hospedeiro a
oliveira, a cochonilha negra, Saissetia oleae (Olivier) é uma praga importante desta cultura de
Norte a Sul do continente português. Essencial para a realização de uma protecção oportuna,
eficaz e económica contra a praga e a disponibilidade de conhecimentos de índole regional
sobre a sua biologia, designadamente sobre 0 seu cicio biológico. Tal foi 0 objectivo para que se
pretendeu contribuir com o presente estudo, relativamente à Terra Quente Transmontana. O
estudo em causa decorreu na região de Mirandela em 1996 e 1997. Os resultados obtidos
sugerem que o insecto completa uma geração anual, hibernando sobretudo no 2°, 3° e 4° instares.
A oviposição é muito escalonada, prolongando-se por vários meses. Também é relativamente
longo o período de ocorrência de 1° instar, que se inicia a partir de fins de Maio. O número de
indivíduos de 2° instar aumenta progressivamente a partir de Julho e o de 3° instar em Agosto/Setembro
Sterol and fatty acid profile in negrinha and santulhana varietal olive oils from Trás-os-Montes region
info:eu-repo/semantics/publishedVersio
Transition from tunneling to direct contact in tungsten nanojunctions
We apply the mechanically controllable break junctions technique to
investigate the transition from tunneling to direct contact in tungsten. This
transition is quite different from that of other metals and is determined by
the local electronic properties of the tungsten surface and the relief of the
electrodes at the point of their closest proximity. The conductance traces show
a rich variety of patterns from the avalanche-like jump to a mesoscopic contact
to the completely smooth transition between direct contact and tunneling. Due
to the occasional absence of an adhesive jump the conductance of the contact
can be continuously monitored at ultra-small electrode separations. The
conductance histograms of tungsten are either featureless or show two distinct
peaks related to the sequential opening of spatially separated groups of
conductance channels. The role of surface states of tungsten and their
contribution to the junction conductance at sub-Angstrom electrode separations
are discussed.Comment: 6 pages, 6 figure
The striped soldier shrimp Plesionika edwardsii (Crustacea:Decapoda:Pandalidae) from the cape Verde Islands
This study is part of the PROACTIVA 1-2 (2009-2012) and MARPROF-CV (2010-2014) projects, in the
framework of the Canary Islands Government and UE PCT MAC 2007-2013 programmes respectively.
Research has mainly focused on the stock assessment of the striped soldier shrimp, Plesionika edwardsii
(Brandt, 1851), because it has shown moderate to high levels of fishing yield and abundances compatible
with the development of a new sustainable fishery in the Cape Verde Islands.
Cruises took place on board the R/V Prof. Ignacio Lozano. Four 15-day surveys have been conducted to
date: Cabo Verde 2010-04 (April 2010), Camar˜ao-1 (November 2011), Camar˜ao-2 (Mars 2012) and Camar
˜ao-3 (July 2012). An innovative fishing gear so-called multiple semi-floating shrimp trap (MSFST)
was used. Each fishing line was composed by 40-65 traps operating around 2.4 m above the seafloor,
using Decapterus macarellus (Carangidae) as unique bait of the traps. Fishing depth was 66-458 m, and
efective fishing time was 16-18 h. Each trap was attached to the main bottom line every 15 m, and the
maximum attraction of this bait was established to be 100 or 150 m, according to the experience gained
from the local fishery for deep-sea lobsters. So density by area was calculated assuming two different
areas of attraction of the fishing gear. Initial biomass was estimated from depletion experiments at different
abundance stations by applying the Leslie & Davis (1939) method, modified by Ricker (1975). Each
fishing operation was classified according to its yield (CPUE in g/trap/night). The potential fishing planar
area was estimated between the isobathymetric lines between 90 and 220 m. Total biomasses (Bt) were
calculated from areas (km2) and mean minimum/maximum densities (kg/km2). Maximum sustainable
yield (MSY) was estimated from Bt using the Beddington and Cooke (1983) model by entering natural
mortality (0.6), growth rate (0.53 year�1) and recruitment age (1.32 year), which are the parameters for
this target species published for the Canaries. These parameters estimate a biological exploitation rate
( ) of 0.262. Interpolations were applied to estimate MSY for insular stocks representing lesser than 5%
of the total fishing grounds for this species in the archipelago.
The MSY estimated by depletion were 30.5 tons/year for the stock of S˜ao Vicente, Santa Luzia, Ilheus
and S˜ao Nicolau, 10 tons/year for the stock of Santiago, 138.8 tons/year for the stock of Boa Vista
and Maio, and 5.6 tons/year for the stock of Sal. The small stocks estimated by interpolation were:
4.5 tons/year for the stock of Santo Ant˜ao, 1.3 tons/year for the stock of Fogo, and 1.8 tons/year for
the stock of Brava and Ilheus. In total, 192.5 tons per year was the total MSY for the striped soldier
shrimp around the islands of the Cape Verde archipelago, occupying a total area of 1,918 km2 of new
fishing grounds at between 90 and 220 m of depth. In comparison with the traditional bottom trap
used in the Canary Islands, the innovative fishing gear MSFST were proved to be more selective for
pandalid shrimps, minimizing the gear impact on the seafloor as well as the by-catch by reducing the
discards. Depletion methods are based on the assumption of a closed system, that is with minimum or
zero immigration between neighbouring areas. The straight forward decline of CPUEs obtained during
the depletion experiments seems to confirm that P. edwardsii is a low mobility species, making this
assumption valid at least during short-time periods. Because of the bathymetry profile of these islands,the depth range is from very close (few nautical miles in Santiago) to far away (10-12 n.m. in Boa Vista)
to the coastline.
Fishing effort should be controlled on the basis of quotas, number of fishing vessels and a precautionary
approach in order to ensure that catching is commensurate with sustainable levels of exploitation. MSY
estimates suggest that this new Capeverdean fishery should be carried out by specialized medium-sized
fishing vessels. During the last decades a combination of shrimp trawling and industrial trapping activity
has threatened over-exploitation in the Mediterranean fisheries targeting on P. edwardsii; currently the
shrimp collapse has conducted to the decline of these fisheries. Can the Cape Verde regulatory bodies
and all the stakeholders involved learn the lessons this teaches us about this resource management
By-catch composition of the striped soldier shrimp Plesionika edwardsii (Crustace: Decapoda: Pandalidae) experimental fishery in the Cape Verde Islands
This work focuses on the by-catch composition of Plesionika edwardsii experimental fishery in the Cape
Verde Islands. Obtaining information on abundance, composition and lifecycle of species involved in this
potential fishery is useful, in order to ensure its sustainable development under an ecosystem approach.
The first step towards this goal is the description of catches.
Four 15-day research surveys were conducted on board the R/V Prof. Ignacio Lozano: April 2010 (S˜ao
Vicente and Santa Luzia islands), November 2011 (Santiago island), March 2012 (Boa Vista island,)
and July 2012 (Sal and S˜ao Nicolau islands). The working depths were between 66 and 458 m depth.
A standardized innovative fishing gear was used, so-called multiple semi-floating shrimp traps. Each
fishing line was composed by 40-65 traps operating around 2.4 m above the seafloor, using Decapterus
macarellus (Carangidae) as unique bait of the traps.
Multiple semi-floating shrimp traps is a passive fishing system that allows catch and release sea significant
part of the unwanted catches, as in the case of Chondrichthyes or Anguilliformes, reducing the
fishing impact on non-target species.
The main by-catch was composed of 53 species belonging to three groups including Chondrichthyes
(three families and three species), Crustacea (11 families and 19 species) and Osteichthyes (15 families
and 29 species). Plesionika edwardsii, the target species of this fishery, represented 97.8% of
the catch in terms of abundance and 40.1% in biomass. By-catch represented 59.9% of total catch in
terms of biomass. Osteichthyes (87.5%) were the dominant group and was represented by the following
main families; Sparidae (33.9%), Moridae (32.5%), Muraenidae (32.5%), Scorpaenidae (9.9%) and
Tetraodontidae (9.8%). Chondrichthyes (11.6%) were composed by Centrophoridae (65.3%) and Triakidae
(34.1%). Finally, Crustacea (1.9%) were chiefly composed by Pandalidae (79.1%). However,
different families represented by specific species were found to be dominant around each island. Sparidae
were the dominant family represented by Pagellus acarne (46.2% of total by-catch) at S˜ao Vicente,
and by Dentex macrophthalmus (42.6%) at Boa Vista. Tetraodontidae with Sphoeroides pachygaster
(25.9%) and Sparidae with P. acarne (25.1%) were the co-dominant families in the by-catch around
Santa Luzia. Muraenidae were the dominant family represented by Gymnothorax polygonius (69.4%)
at Sal, and by Muraena helena (63.4%) at S˜ao Nicolau. Finally, Scorpaenidae with Pontinus kuhlii
(22.3%) and Moridae with Physiculus cyanostrophus (22.1%) were the co-dominant families of the bycatch
around Santiago.
Acknowledgements: This study is part of the PROACTIVA 1-2 (2009-2012) and MARPROF-CV
(2010-2014) projects, in the framework of the Canary Islands Government and UE PCT MAC 2007-
2013 programmes respectively
Prognostic value of numerical chromosome aberrations in multiple myeloma: A FISH analysis of 15 different chromosomes
Este trabajo proporcionó la primera idea de que la deleción del Cr13 tiene valor pronóstico pe-yorativo en MM. Proporcionó las primeras pistas del valor de la FISH en MM, que sigue siendo la herramienta fundamental para evaluar el pronóstico en estos pacientes en todo el mundo[EN]Recent observations indicate that chromosome aberrations are important prognostic factors in patients with multiple myeloma (MM) treated with high-dose chemotherapy. Nevertheless, the inherent problems of conventional cytogenetics have hampered the systematic evaluation of this parameter in series of patients treated with conventional chemotherapy. Fluorescence in situ hybridization (FISH) analysis is an attractive alternative for evaluation of numerical chromosomal changes. In the present study, we analyze the relationship between aneuploidies of 15 different chromosomes assessed by FISH and prognosis in a series of 63 patients with MM treated with conventional chemotherapy. After a median follow-up of 61 months (range, 6 to 109), 49% of patients are still alive with a median survival of 33 months. The overall incidence of numerical chromosome abnormalities was 70%. This incidence significantly increased when seven or more chromosomes were analyzed (53 patients), reaching 81%. Trisomies of chromosomes 6, 9, and 17 were associated with prolonged survival (P = .033, P = .035, and P = .026, respectively); by contrast, overall survival (OS) was lower in cases with monosomy 13 (as assessed by deletion of Rb gene, P = .0012). From the clinical point of view, loss of Rb gene was associated with a poor performance status; low hemoglobin levels; high creatinine, C-reactive protein, and lactic dehydrogenase serum levels; high percentage of bone marrow plasma cells (BMPC); extensive bone lytic lesions; and advanced clinical stage. Other chromosome abnormalities such as trisomy of chromosome 9 and 17 were associated with good prognostic features including high hemoglobin levels, early clinical stage, beta2microglobulin less than 6 micro/mL, and low percentage of BMPC. A multivariate analysis for OS showed that S-phase PC greater than 3% (P = .010) and beta2microglobulin serum levels greater than 6 micro/mL (P = .024), together with monosomy of chromosome 13 (P = .031) and nontrisomy of chromosome 6 (P = .048) was the best combination of independent parameters for predicting survival in patients with MM. According to these results, chromosomal analysis is of great use in patients with MM at diagnosis to have a correct prognostic evaluation for clinical decision making.Hospital Universitario de Salamanca
Universidad de SalamancaHospital Universitario de Salamanc
Density functional method for nonequilibrium electron transport
We describe an ab initio method for calculating the electronic structure,
electronic transport, and forces acting on the atoms, for atomic scale systems
connected to semi-infinite electrodes and with an applied voltage bias. Our
method is based on the density functional theory (DFT) as implemented in the
well tested Siesta approach (which uses non-local norm-conserving
pseudopotentials to describe the effect of the core electrons, and linear
combination of finite-range numerical atomic orbitals to describe the valence
states). We fully deal with the atomistic structure of the whole system,
treating both the contact and the electrodes on the same footing. The effect of
the finite bias (including selfconsistency and the solution of the
electrostatic problem) is taken into account using nonequilibrium Green's
functions. We relate the nonequilibrium Green's function expressions to the
more transparent scheme involving the scattering states. As an illustration,
the method is applied to three systems where we are able to compare our results
to earlier ab initio DFT calculations or experiments, and we point out
differences between this method and existing schemes. The systems considered
are: (1) single atom carbon wires connected to aluminum electrodes with
extended or finite cross section, (2) single atom gold wires, and finally (3)
large carbon nanotube systems with point defects.Comment: 18 pages, 23 figure
Departure from the vogel behaviour in the glass transition region-thermally stimulated recovery, creep and dynamic mechanical analysis studies
In this work the study of the dynamics of the segmental motions close to Tg of a poly(methyl methacrylate), PMMA, network was analysed
by distinct mechanical spectroscopy techniques. Three techniques were employed: dynamic mechanical analysis (DMA), creep and
thermally stimulated recovery (TSR). The time–temperature superposition principle was applied to the DMA and creep results, and master
curves were successfully constructed. A change from a Vogel to an Arrhenius behaviour was observed in these results. Above Tg it was found
a distinct temperature dependence for the retardation times calculated from creep and the relaxation times calculated from DMA. This
unexpected behaviour was attributed to the merging of the a and the b relaxations that occurs in PMMA systems. The apparent activation
energies ðEaÞ were also calculated from DMA, creep and TSR experiments. Above Tg the Ea values obtained agreed very well for all the
techniques. In addition, the fragility exhibited by this material was investigated by the mechanical spectroscopy techniques referred above
and by differential scanning calorimetry (DSC). The obtained values of the fragility index m indicated that the PMMA network is a
kinetically fragile system. The thermodynamic manifestation of the fragility was also analysed
Deformations of nearly Kähler instantons
We formulate the deformation theory for instantons on nearly Kähler six-manifolds using spinors and Dirac operators. Using this framework we identify the space of deformations of an irreducible instanton with semisimple structure group with the kernel of an elliptic operator, and prove that abelian instantons are rigid. As an application, we show that the canonical connection on three of the four homogeneous nearly Kähler six-manifolds G/H is a rigid instanton with structure group H. In contrast, these connections admit large spaces of deformations when regarded as instantons on the tangent bundle with structure group SU(3)
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