2,039 research outputs found
From the braided to the usual Yang-Baxter relation
Quantum monodromy matrices coming from a theory of two coupled (m)KdV
equations are modified in order to satisfy the usual Yang-Baxter relation. As a
consequence, a general connection between braided and {\it unbraided} (usual)
Yang-Baxter algebras is derived and also analysed.Comment: 13 Latex page
TBA-like equations and Casimir effect in (non-)perturbative AdS/CFT
We consider high spin, , long twist, , planar operators (asymptotic
Bethe Ansatz) of strong SYM. Precisely, we compute the minimal
anomalous dimensions for large 't Hooft coupling to the lowest order
of the (string) scaling variable with GKP string size . At the leading order ,
we can confirm the O(6) non-linear sigma model description for this bulk term,
without boundary term . Going further, we derive,
extending the O(6) regime, the exact effect of the size finiteness. In
particular, we compute, at all loops, the first Casimir correction (in terms of the infinite size O(6) NLSM), which reveals only one
massless mode (out of five), as predictable once the O(6) description has been
extended. Consequently, upon comparing with string theory expansion, at one
loop our findings agree for large twist, while reveal for negligible twist,
already at this order, the appearance of wrapping. At two loops, as well as for
next loops and orders, we can produce predictions, which may guide future
string computations.Comment: Version 2 with: new exact expression for the Casimir energy derived
(beyond the first two loops of the previous version); UV theory formulated
and analysed extensively in the Appendix C; origin of the O(6) NLSM
scattering clarified; typos correct and references adde
A braided Yang-Baxter Algebra in a Theory of two coupled Lattice Quantum KdV: algebraic properties and ABA representations
A generalization of the Yang-Baxter algebra is found in quantizing the
monodromy matrix of two (m)KdV equations discretized on a space lattice. This
braided Yang-Baxter equation still ensures that the transfer matrix generates
operators in involution which form the Cartan sub-algebra of the braided
quantum group. Representations diagonalizing these operators are described
through relying on an easy generalization of Algebraic Bethe Ansatz techniques.
The conjecture that this monodromy matrix algebra leads, {\it in the cylinder
continuum limit}, to a Perturbed Minimal Conformal Field Theory description is
analysed and supported.Comment: Latex file, 46 page
Metacestodes of elasmobranch tapeworms in octopus vulgaris (Mollusca, cephalopoda) from central mediterranean—SEM and molecular data
Cephalopods are intermediate/paratenic hosts in the life cycle of elasmobranch tapeworms, nevertheless most records of infection in this group of mollusks are outdated and fragmentary. The present work aimed to investigate the cestode fauna of the common octopus Octopus vulgaris from the Tyrrhenian Sea (Central Mediterranean). The parasitic stages were characterized by light and Scanning Electron Microscopy (SEM) and sequencing of 28S rDNA. Three cestode taxa were identified to the genus level: the onchoproteocephalidean Acanthobothrium sp. (prevalence 28%), the “tetraphyllidean” Anthobothrium sp. (prevalence 13%) and the trypanorhynch Nybelinia sp. (prevalence 3%). The remarkable prevalence observed for gastrointestinal cestodes highlight a possible important role of O. vulgaris in the transmission of elasmobranch tapeworms, particularly Onchoproteocephalideans. Furthermore, the present work provides, for the first time, detailed morphological (SEM) and molecular support to confirm the occurrence of Anthobothrium sp. in cephalopod hosts. In order to gain higher taxonomic resolution for the identified taxa, we stress the need to collect further morphological and molecular data of adult cestodes infecting their elasmobranch definitive hosts
Morphological and molecular characterization of two gastrointestinal parasites in Mustelus mustelus (Linnaeus, 1758) from Adriatic Sea
Specimens of common smooth-hound, Mustelus mustelus, fished as bycatch in the Northwestern Adriatic Sea, were
subjected to a complete parasitological examination. Parasites were processed for morphological and morphometric
analyses aimed at identifying them to the species level. Parasite identity was confirmed through amplification and
sequencing of 28S rDNA. The nematode Acanthocheilus rotundatus was recovered from the stomach and the proximal
intestine, while the cestode Calliobothrium verticillatum was collected from the spiral valve. Our results confirm the
occurrence of C. verticillatum in M. mustelus from the Mediterranean Sea and provide the first sequence data of A.
rotundatus from the same area. Updated knowledge on the parasite fauna of M. mustelus from Adriatic Sea contributes to elucidating aspects of the ecology, biology and health status of elasmobranchs from the Mediterranean Sea, providing
useful information for their proper management and conservation
Parasitic infection in the scyphozoan Rhizostoma pulmo (Macri, 1778)
: Very little information is reported for parasites of cnidarians, therefore, the present work aimed to investigate parasitic infections in one of the most widespread jellyfish in the Mediterranean Sea, Rhizostoma pulmo. The goals were to determine prevalence and intensity of parasites in R. pulmo, identify the species involved through morphological and molecular analysis, test whether infection parameters differ in different body parts and in relation to jellyfish size. 58 individuals were collected, 100% of them infected with digenean metacercariae. Intensity varied between 18.7 ± 6.7 per individual in 0-2 cm diameter jellyfish up to 505 ± 50.6 in 14 cm ones. Morphological and molecular analyses suggest that the metacercariae belonged to the family Lepocreadiidae and could be possibly assigned to the genus Clavogalea. Prevalence values of 100% suggest that R. pulmo is an important intermediate host in the life cycle of lepocreadiids in the region. Our findings also support the hypothesis that R. pulmo is an important part in the diet of teleost fish, which are reported as definitive hosts of lepocreadiids, since trophic transmission is necessary for these parasites to complete their life cycles. Parasitological data may therefore be useful to investigate fish-jellyfish predation, integrating traditional methods such as gut contents analysis
The generalised scaling function: a systematic study
We describe a procedure for determining the generalised scaling functions
at all the values of the coupling constant. These functions describe
the high spin contribution to the anomalous dimension of large twist operators
(in the sector) of SYM. At fixed , can be
obtained by solving a linear integral equation (or, equivalently, a linear
system with an infinite number of equations), whose inhomogeneous term only
depends on the solutions at smaller . In other words, the solution can be
written in a recursive form and then explicitly worked out in the strong
coupling regime. In this regime, we also emphasise the peculiar convergence of
different quantities ('masses', related to the ) to the unique mass gap
of the nonlinear sigma model and analyse the first next-to-leading order
corrections.Comment: Latex version, journal version (with explanatory appendices and more
references
Operator with large spin and spinning D3-brane
We consider the conformal dimension of an operator with large spin, using a
spinning D3-brane with electric flux in AdS_5 x S^5 instead of spinning
fundamental string. This spinning D3-brane solution seems to correspond to an
operator made by taking trace in a large symmetric representation. The
conformal dimension, the spin and the R-charge show a scaling relation in a
certain region of parameters. In the small string charge limit, the result is
consistent with the fundamental string picture. There is a phase transition
when the fundamental string charge become larger than a certain critical value;
there is no stable D3-brane solution above the critical value.Comment: 16 pages, 4 figures. v2: typos corrected, references added, series
expansion of anomalous dimension added. v3: a reference added, comment on
calculation in gauge theor
From biomass of poplar utilizations to byproducts
According to recent bioeconomy programs, chemical compounds derived from natural sources will be more available in regions where these compounds can be obtained economically than more expensive synthetic chemicals. In addition, the biorefinery is becoming an important aspect for green chemistry development aimed at ensuring the necessity to achieve the best objectives as favourable as possible from restricted natural resources such as forest biomass. One of the main scope is to generate diversified, innovative and renewable products using on-site bioresources such as biomass of wood and tree residues. Poplar tree species, including all their huge varieties, are largely cultivated in the world as a fast growing bioenergy crop. However the enormous potential of this specie in the other fields is still under-evaluated. The aim of this study was to verify the influence of thermal treatment at 180, 200 and 220 °C on wood extracts obtained via three different extraction techniques: Maceration, ultrasound-assisted extraction and accelerated solvent extraction. Results showed the effect of heat treatments and extraction techniques on polyphenol, flavonoid contents and antioxidant activity. This investigation clearly showed the differential effects of temperature and extraction techniques on both antioxidant activity and secondary compounds contents
Comparative Therapeutic Effects of Natural Compounds Against Saprolegnia spp. (Oomycota) and Amyloodinium ocellatum (Dinophyceae)
The fish parasites Saprolegnia spp. (Oomycota) and Amyloodinium ocellatum (Dinophyceae) cause important losses in freshwater and marine aquaculture industry, respectively. The possible adverse effects of compounds used to control these parasites in aquaculture resulted in increased interest on the search for natural products with antiparasitic activity. In this work, eighteen plant-derived compounds (2′,4′-Dihydroxychalcone; 7-Hydroxyflavone; Artemisinin; Camphor (1R); Diallyl sulfide; Esculetin; Eucalyptol; Garlicin 80%; Harmalol hydrochloride dihydrate; Palmatine chloride; Piperine; Plumbagin; Resveratrol; Rosmarinic acid; Sclareolide; Tomatine, Umbelliferone, and Usnic Acid) have been tested in vitro. Sixteen of these were used to determine their effects on the gill cell line G1B (ATCC®CRL-2536™) and on the motility of viable dinospores of Amyloodinium ocellatum, and thirteen were screened for inhibitory activity against Saprolegnia spp. The cytotoxicity results on G1B cells determined that only two compounds (2′,4′-Dihydroxychalcone and Tomatine) exhibited dose-dependent toxic effects. The highest surveyed concentrations (0.1 and 0.01 mM) reduced cell viability by 80%. Upon lowering the compound concentration the percentage of dead cells was lower than 20%. The same two compounds revealed to be potential antiparasitics by reducing in a dose-dependent manner the motility of A. ocellatum dinospores up to 100%. With respect to Saprolegnia, a Minimum Inhibitory Concentration was found for Tomatine (0.1 mM), Piperine and Plumbagin (0.25 mM), while 2′,4′-Dihydroxychalcone considerably slowed down mycelial growth for 24 h at a concentration of 0.1 mM. Therefore, this research allowed to identify two compounds, Tomatine and 2′,4′-Dihydroxychalcone, effective against both parasites. These compounds could represent promising candidates for the treatment of amyloodiniosis and saprolegniosis in aquaculture. Nevertheless, further in vitro and in vivo tests are required in order to determine concentrations that are effective against the considered pathogens but at the same time safe for hosts, environment and consumers
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