4,099 research outputs found

    Water quality investigation of Loweswater, Cumbria

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    This is the final report to the Environment Agency: Water Quality Investigation of Loweswater, Cumbria. The project employs palaeolimnological techniques to evaluate the extent of eutrophication at Loweswater

    Controlling chaos in the quantum regime using adaptive measurements

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    The continuous monitoring of a quantum system strongly influences the emergence of chaotic dynamics near the transition from the quantum regime to the classical regime. Here we present a feedback control scheme that uses adaptive measurement techniques to control the degree of chaos in the driven-damped quantum Duffing oscillator. This control relies purely on the measurement backaction on the system, making it a uniquely quantum control, and is only possible due to the sensitivity of chaos to measurement. We quantify the effectiveness of our control by numerically computing the quantum Lyapunov exponent over a wide range of parameters. We demonstrate that adaptive measurement techniques can control the onset of chaos in the system, pushing the quantum-classical boundary further into the quantum regime

    Feeding spectra and activity of the freshwater crab Trichodactylus kensleyi (Decapoda: Brachyura: Trichodactylidae) at La Plata basin

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    Background: In inland water systems, it is important to characterize the trophic links in order to identify the ‘trophic species’ and, from the studies of functional diversity, understand the dynamics of matter and energy in these environments. The aim of this study is to analyze the natural diet of Trichodactylus kensleyi of subtropical rainforest streams and corroborate the temporal variation in the trophic activity during day hours. Results: A total of 15 major taxonomic groups were recognized in gut contents. The index of relative importance identified the following main prey items in decreasing order of importance: vegetal remains, oligochaetes, chironomid larvae, and algae. A significant difference was found in the amount of full stomachs during day hours showing a less trophic activity at midday and afternoon. The index of relative importance values evidenced the consumption of different prey according to day moments. Results of the gut content indicate that T. kensleyi is an omnivorous crab like other trichodactylid species. Opportunistic behavior is revealed by the ingestion of organisms abundant in streams such as oligochaetes and chironomid larvae. The consumption of allochthonous plant debris shows the importance of this crab as shredder in subtropical streams. However, the effective assimilation of plant matter is yet unknown in trichodactylid crabs. Conclusions: This research provides knowledge that complements previous studies about trophic relationships of trichodactylid crabs and supported the importance of T. kensleyi in the transference of energy and matter from benthic community and riparian sources to superior trophic levels using both macro- and microfauna.Fil: Williner, Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; ArgentinaFil: de Azevedo Carvalho, Debora. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Collins, Pablo Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentin

    The consequences of the effects of the chemotherapeutic drug (vincristine) in organs and the influence on the bioavailability of two radio-biocomplexes used for bone evaluations in balb/c female mice

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    The development of animal model to evaluate the toxicological action of compounds used as pharmaceutical drugs is desired. The model described in this work is based on the capability of drugs to alter the bioavailability of radiopharmaceuticals (radiobiocomplexes) labeled with technetium-99 m(99mTc). There are evidences that the bioavailability or the pharmacokinetic of radiobiocomplexes can be modified by some factors, as drugs, due to their toxicological action in specific organs. Vincristine is anatural product that has been utilized in oncology. The vincristine effect on the bioavailability of the radiobiocomplexes 99mTc- ethylenediphosphonic acid (99mTc-MDP) and 99mTc-pyrophosphate (99mTc- PYP) in Balb/c female mice was evaluated. The fragments of kidney were processed to light microscopy and transmission electron microscopy. The aim of this work was to study at structural and ultrastructural levels the alterations caused by vincristine in organs. One hour after the last dose ofvincristine, 99mTc-PYP or 99mTc-MDP was injected, the animals were sacrificed and the percentage of radioactivity (%ATI) was determined in the isolated organs. Concerning 99mTc-PYP, the %ATI (i) decreased in spleen, thymus, lymph nodes (inguinal and mesentheric), kidney, lung, liver, pancreas, stomach, heart and brain and (ii) increased in bone and thyroid. Concerning 99mTc-MDP, the %ATI (iii) decreased in spleen, thymus, lymph nodes (inguinal and mesentheric), kidney, liver, pancreas,stomach, heart, brain, bone, ovary and uterus. In conclusion, the toxic effect of vincristine in determined organs could be responsible for the alteration of the uptake of the studied radiobiocomplexes

    PROP1 gene analysis in Portuguese patients with combined pituitary hormone deficiency

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    OBJECTIVE: Mutations of the PROP1 gene lead to combined pituitary hormone deficiency (CPHD), which is characterized by a deficiency of GH, TSH, LH/FSH, PRL and, less frequently, ACTH. This study was undertaken to investigate the molecular defect in a cohort of patients with CPHD. DESIGN, PATIENTS AND MEASUREMENTS: A multicentric study involving 46 cases of CPHD (17 familial cases belonging to seven kindreds and 29 sporadic cases) selected on the basis of clinical and hormonal evidence of GH deficiency, central hypothyroidism and hypogonadotrophic hypogonadism, in the absence of an identified cause of hypopituitarism. Mutations of PROP1 were investigated by DNA sequencing. Clinical, hormonal and neuroradiological data were collected at each centre. RESULTS: PROP1 mutations were identified in all familial cases: five kindreds presented a c. 301-302delAG mutation, one kindred presented a c. 358C --> T (R120C) mutation and one presented a previously unreported initiation codon mutation, c. 2T --> C. Of the 29 sporadic cases, only two (6.9%) presented PROP1 germline mutations (c. 301-302delAG, in both). Phenotypic variability was observed among patients with the same mutations, particularly the presence and age of onset of hypocortisolism, the levels of PRL and the results of pituitary imaging. One patient presented a sellar mass that persisted into adulthood. CONCLUSIONS: This is the first report of a mutation in the initiation codon of the PROP1 gene and this further expands the spectrum of known mutations responsible for CPHD. The low mutation frequency observed in sporadic cases may be due to the involvement of other unidentified acquired or genetic cause

    Salvage for cervical recurrences of head and neck cancer with dissection and interstitial high dose rate brachytherapy

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    Salvage therapy in head and neck cancer (HNC) is a controversy issue and the literature is scarce regarding the use of interstitial high-dose rate brachytherapy (I-HDR) in HNC. We evaluated the long-term results of a treatment policy combining salvage surgery and I-HDR for cervical recurrences of HNC. Charts of 21 patients treated from 1994 to 2004 were reviewed. The crude local control rate for all patients was 52.4%. The 5- and 8-years overall (OS) and local relapse-free survival (LRFS) rates were 50%, 42.9%, 42.5% and 28.6%, respectively. The only predictive factor associated to LFRS and OS was negative margin status (p = 0.0007 and p = 0.0002). We conclude that complete surgery is mandatory for long term control and the doses given by brachytherapy are not high enough to compensate for microscopic residual disease after surgery

    Anomalous tqγtq\gamma coupling effects in exclusive radiative B-meson decays

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    The top-quark FCNC processes will be searched for at the CERN LHC, which are correlated with the B-meson decays. In this paper, we study the effects of top-quark anomalous interactions tqγtq\gamma in the exclusive radiative BKγB\to K^*\gamma and BργB\to\rho\gamma decays. With the current experimental data of the branching ratios, the direct CP and the isospin asymmetries, bounds on the coupling κtcRγ\kappa_{tcR}^{\gamma} from BKγB\to K^*\gamma and κtuRγ\kappa_{tuR}^{\gamma} from BργB\to \rho\gamma decays are derived, respectively. The bound on κtcRγ|\kappa_{tcR}^{\gamma}| from B(BKγ){\mathcal B}(B\to K^{*}\gamma) is generally compatible with that from B(BXsγ){\mathcal B}(B\to X_{s}\gamma). However, the isospin asymmetry Δ(Kγ)\Delta(K^{*}\gamma) further restrict the phase of κtcRγ\kappa_{tcR}^{\gamma}, and the combined bound results in the upper limit, B(tcγ)<0.21\mathcal B(t\to c\gamma)<0.21%, which is lower than the CDF result. For real κtcRγ\kappa_{tcR}^{\gamma}, the upper bound on B(tcγ)\mathcal B(t\to c\gamma) is about of the same order as the 5σ5\sigma discovery potential of ATLAS with an integrated luminosity of 10fb110 {\rm fb}^{-1}. For BργB\to\rho\gamma decays, the NP contribution is enhanced by a large CKM factor Vud/Vtd|V_{ud}/V_{td}|, and the constraint on tuγtu\gamma coupling is rather restrictive, B(tuγ)<1.44×105\mathcal B(t\to u\gamma)<1.44\times 10^{-5}. With refined measurements to be available at the LHCb and the future super-B factories, we can get close correlations between BVγB\to V \gamma and the rare tqγt\to q\gamma decays, which will be studied directly at the LHC ATLAS and CMS.Comment: 25 pages, 15 figures, pdflate

    Monte Carlo simulation of expected outcomes with the AcrySof® toric intraocular lens

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    <p>Abstract</p> <p>Background</p> <p>To use a Monte Carlo simulation to predict postoperative results with the AcrySof<sup>® </sup>Toric lens, evaluating the likelihood of over- or under-correction using various toric lens selection criteria.</p> <p>Methods</p> <p>Keratometric data were obtained from a large patient population with preoperative corneal astigmatism <= 2.50D (2,000 eyes). The probability distributions for toric marking accuracy, surgically induced astigmatism and lens rotation were estimated using available data. Anticipated residual astigmatism was calculated using a Monte Carlo simulation under two different lens selection scenarios.</p> <p>Results</p> <p>This simulation demonstrated that random errors in alignment, surgically induced astigmatism and lens rotation slightly reduced the overall effect of the toric lens. Residual astigmatism was statistically significantly higher under the simulation of surgery relative to an exact calculation (p < 0.05). The simulation also demonstrated that more aggressive lens selection criteria could produce clinically significant reductions in residual astigmatism in a high percentage of patients.</p> <p>Conclusion</p> <p>Monte Carlo simulation suggests that surgical variability and lens orientation/rotation variability may combine to produce small reductions in the correction achieved with the AcrySof<sup>® </sup>Toric<sup>® </sup>IOL. Adopting more aggressive lens selection criteria may yield significantly lower residual astigmatism values for many patients, with negligible overcorrections. Surgeons are encouraged to evaluate their AcrySof<sup>® </sup>Toric<sup>® </sup>outcomes to determine if they should modify their individual lens selection criteria, or their default surgically induced astigmatism value, to benefit their patients.</p
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