1,219 research outputs found

    DDF operators, open string coherent states and their scattering amplitudes

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    We study interactions of string coherent states in the DDF (after Di Vecchia, Del Giudice, Fubini) formalism. For simplicity we focus on open bosonic strings. After reviewing basic properties of DDF operators and of excited open strings, we present some classical profiles and show how they become more and more compact as the number of harmonics increases at fixed mass. We then compute various three- and four-point amplitudes with insertions of coherent states, tachyons and vector bosons on the boundary of the disk relying on a convenient choice of reference null momenta. We find that the amplitudes exponentiate in a rather subtle and interesting way. We then study the high-energy fixed-angle limit, dominated by a saddle-point when coherent states are present, and the soft behaviour as the momentum of a vector boson is taken to zero. We briefly comment on generalisation of our analysis to multiple intersecting and magnetised D-branes and to closed strings.Comment: 39 pages, 6 figure

    Patient satisfaction after auditory implant surgery. ten-year experience from a single implanting unit center

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    Conclusions: The satisfaction rate of the subjects with an auditory implant appears strictly related to the resulting auditory improvement, and the surgical variables would play a prevailing role in respect to the esthetic factors. Objectives: To assess the rate of satisfaction in subjects who underwent the surgical application of an auditory device at a single Implanting Center Unit. Method: A series of validated questionnaires has been administered to subjects who underwent the surgical application of different auditory devices. The Glasgow Benefit Inventory (GBI), the Visual Analog Scale (VAS), and the Abbreviated Profile of Hearing Aid Benefit (APHAB) have been used to compare the implanted situation with the hearing-aided one; a percutaneous bone conductive implant (pBCI) with an active middle ear implant (AMEI) on the round window in mixed hearing loss; and an invisible, fully-implantable device with a frankly and bulky semi-implantable device. Results: The mean GBI scores were higher in Vibrant Soundbridge (VSB)VR and BonebridgeVR subjects, without significant differences among the various devices. The mean VAS score increased for all the devices in comparison with the conventional hearing aid. The mean APHAB score was similarly better in the implanted condition as total and partial scores

    The T2238C human atrial natriuretic peptide molecular variant and the risk of cardiovascular diseases

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    Atrial natriuretic peptide (ANP) is a cardiac hormone which plays important functions to maintain cardio-renal homeostasis. The peptide structure is highly conserved among species. However, a few gene variants are known to fall within the human ANP gene. The variant rs5065 (T2238C) exerts the most substantial effects. The T to C transition at the 2238 position of the gene (13-23% allele frequency in the general population) leads to the production of a 30-, instead of 28-, amino-acid-long α-carboxy-terminal peptide. In vitro, CC2238/αANP increases the levels of reactive oxygen species and causes endothelial damage, vascular smooth muscle cells contraction, and increased platelet aggregation. These effects are achieved through the deregulated activation of type C natriuretic peptide receptor, the consequent inhibition of adenylate cyclase activity, and the activation of Giα proteins. In vivo, endothelial dysfunction and increased platelet aggregation are present in human subjects carrying the C2238/αANP allele variant. Several studies documented an increased risk of stroke and of myocardial infarction in C2238/αANP carriers. Recently, an incomplete response to antiplatelet therapy in ischemic heart disease patients carrying the C2238/αANP variant and undergoing percutaneous coronary revascularization has been reported. In summary, the overall evidence supports the concept that T2238C/ANP is a cardiovascular genetic risk factor that needs to be taken into account in daily clinical practice

    The influence of linseed on rabbit meat quality

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    A research was conducted to study the infl uence of the dietary use of whole linseed on rabbit meat quality. A total of 288 growing rabbits were fed ad libitum (from 55 to 81 d old) with a commercial diet (C) or experimental diets containing 3, 6, or 9% whole linseed (L3, L6 and L9, respectively). After slaughtering, L. lumborum muscles and rabbit meat hamburgers were used to determine pH, colour, cooking loss, total lipid content, fatty acid composition and induced TBARS. Hind leg muscles were analyzed for total lipid content, fatty acid composition and induced TBARS. Finally, a sensory test was carried out to establish the level of acceptability of rabbit meat hamburgers prepared with the meat batters stored for 3 or 6 months at −20°C. The use of linseed determined a lower content of total saturated fatty acid and a higher content of PUFA (P<0.01) in all types of meat. The PUFA n-3 content of the meat increased signifi cantly (P<0.01) with the increasing level of whole linseed in the diet, mainly due to the higher content of α-linolenic acid, which also determined a reduction of the n-6/n-3 PUFA ratio. The hamburgers prepared from L6 and L9 groups exhibited higher TBARS values in comparison with L3 and C. Furthermore, the cooking loss of hamburgers was lower in meat from rabbits fed the control diet (C), intermediate in L3 and higher in L6 and L9 (P<0.01). With regard to sensory analysis, the diet did not determine signifi cant differences in the acceptability of the hamburgers produced with frozen meat batters stored for 3 or 6 months. In general, the use of 3% linseed in diets for growing rabbits could be considered suitable for achieving both the enrichment of the meat with α-linolenic acid and maintaining good product quality characteristics

    String Memories ... openly retold

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    We identify string corrections to the EM memory effect. Though largely negligible in the low-energy limit, the effect become relevant in high-energy collisions and in extreme events. We illustrate our findings in a simple unoriented bosonic string model. Thanks to the coherent effect of the infinite tower of open string resonances, the corrections are non-perturbative in αâ€Č\alpha', modulated in retarded time and slowly decaying even at large distances from the source. Remarkably compact expressions obtain for special choices of the kinematics in tree-level 4-point amplitudes. We discuss further corrections occurring at higher-points and the exponential damping resulting from broadening and shifting of the massive poles due to loops. Finally we estimate the range of the parameters and masses for detectability in semi-realistic (Type I) contexts and propose a rationale for this string memory effect.Comment: 16 pages, 5 figure

    The use of marination to improve poultry meat quality

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    A study was conducted to determine the effect of marination on turkey breast meat quality traits. Breast meat samples were marinated with two types of solution (containing sodium tripolyphosphate, STPP or a commercial mix with sodium carbonate and citrate, COM) and three solution/meat ratios (14, 18, and 22%). Marination with STPP determined a higher increase of meat pH in comparison with COM (pH measured before and after marination = +0.20 vs. +0.14; P≀0.05). The marinade uptake and AK-shear values did not differ between solutions, whereas STPP determined a higher marinade retention (98.2 vs. 97.9%; P≀0.05) and a strong decrease of cooking loss (21.8 vs. 28.1%; P≀0.01) compared with COM. The increase of solution/meat ratio from 14 to 22% significantly raised meat pH, marinade uptake, and cooking loss of the meat. Taking into account both marinade uptake and cooking losses, the use of a 14% solution/meat ratio allowed to maximise processing yield. Overall, compared to non-marinated meat, marinated meat exhibited a higher lightness and yellowness, and a lower AK-shear value after cooking, confirming that this technique can be successfully employed to improve meat texture

    A measure for chaotic scattering amplitudes

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    We propose a novel measure of chaotic scattering amplitudes. It takes the form of a log-normal distribution function for the ratios rn=ÎŽn/ÎŽn+1r_n={\delta_n}/{\delta_{n+1}} of (consecutive) spacings ÎŽn\delta_n between two (consecutive) maxima of the scattering amplitude. We show that the same measure applies to the quantum mechanical scattering on a leaky torus as well as to the decay of highly excited string states into two tachyons. Quite remarkably the rnr_n obey the same distribution that governs the non-trivial zeros of Riemann zeta function.Comment: v2: small corrections, references adde

    Electrodiagnostic Examination of the Tibial Nerve in Clinically Normal Ferrets

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    Tibial nerves of 10 normal domestic ferrets (Mustela putorius furo) were evaluated by means of electrodiagnostic tests: motor nerve conduction studies (MNCSs), supramaximal repetitive nerve stimulation (SRNS), F waves, and cord dorsum potentials (CDPs). Values of conduction velocity, proximal and distal compound muscular action potentials, and amplitudes of MNCS were, respectively, 63.25 ± 7.56 m/sec, 10.79 ± 2.75 mV, and 13.02 ± 3.41 mV. Mean decrements in amplitude and area of compound muscular action potentials of wave 9 with low frequency SRNS were 0.3 ± 3.83% and 0.1 ± 3.51%. The minimum latency of the F waves and the F ratio were, respectively, 8.49 ± 0.65 ms and 1.92 ± 0.17. Onset latency of CDP was 1.99 ± 0.03 ms. These tests may help in diagnosing neuromuscular disorders and in better characterizing the hindlimb paresis reported in many ferrets with systemic illnesses
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