972 resultados para Julian, Fred
Resumo:
Exoplanet transit and Doppler surveys discover many binary stars during their operation that can be used to conduct a variety of ancillary science. Specifically, eclipsing binary stars can be used to study the stellar mass-radius relationship and to test predictions of theoretical stellar evolution models. By cross-referencing 24 binary stars found in the MARVELS Pilot Project with SuperWASP photometry, we find two new eclipsing binaries, TYC 0272-00458-1 and TYC 1422-01328-1, which we use as case studies to develop a general approach to eclipsing binaries in survey data. TYC 0272-00458-1 is a single-lined spectroscopic binary for which we calculate a mass of the secondary and radii for both components using reasonable constraints on the primary mass through several different techniques. For a primary mass of M 1 = 0.92 ± 0.1 M sun, we find M 2 = 0.610 ± 0.036 M sun, R 1 = 0.932 ± 0.076 R sun, and R 2 = 0.559 ± 0.102 R sun, and find that both stars have masses and radii consistent with model predictions. TYC 1422-01328-1 is a triple-component system for which we can directly measure the masses and radii of the eclipsing pair. We find that the eclipsing pair consists of an evolved primary star (M 1 = 1.163 ± 0.034 M sun, R 1 = 2.063 ± 0.058 R sun) and a G-type dwarf secondary (M 2 = 0.905 ± 0.067 M sun, R 2 = 0.887 ± 0.037 R sun). We provide the framework necessary to apply this analysis to much larger data sets.
Resumo:
A new type of advanced encryption standard (AES) implementation using a normal basis is presented. The method is based on a lookup technique that makes use of inversion and shift registers, which leads to a smaller size of lookup for the S-box than its corresponding implementations. The reduction in the lookup size is based on grouping sets of inverses into conjugate sets which in turn leads to a reduction in the number of lookup values. The above technique is implemented in a regular AES architecture using register files, which requires less interconnect and area and is suitable for security applications. The results of the implementation are competitive in throughput and area compared with the corresponding solutions in a polynomial basis.
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The choice of radix is crucial for multi-valued logic synthesis. Practical examples, however, reveal that it is not always possible to find the optimal radix when taking into consideration actual physical parameters of multi-valued operations. In other words, each radix has its advantages and disadvantages. Our proposal is to synthesise logic in different radices, so it may benefit from their combination. The theory presented in this paper is based on Reed-Muller expansions over Galois field arithmetic. The work aims to firstly estimate the potential of the new approach and to secondly analyse its impact on circuit parameters down to the level of physical gates. The presented theory has been applied to real-life examples focusing on cryptographic circuits where Galois Fields find frequent application. The benchmark results show the approach creates a new dimension for the trade-off between circuit parameters and provides information on how the implemented functions are related to different radices.
Resumo:
A dynamic global security-aware synthesis flow using the SystemC language is presented. SystemC security models are first specified at the system or behavioural level using a library of SystemC behavioural descriptions which provide for the reuse and extension of security modules. At the core of the system is incorporated a global security-aware scheduling algorithm which allows for scheduling to a mixture of components of varying security level. The output from the scheduler is translated into annotated nets which are subsequently passed to allocation, optimisation and mapping tools for mapping into circuits. The synthesised circuits incorporate asynchronous secure power-balanced and fault-protected components. Results show that the approach offers robust implementations and efficient security/area trade-offs leading to significant improvements in turnover.
Resumo:
Reproductive performance in the high-yielding dairy cow has severely decreased in the last 40 yr. The aim of this study was to compare the effectiveness of 4 nutritional strategies in improving the reproductive performance of high-yielding dairy cows. It was hypothesized that offering cows a high-starch ration in early lactation would enhance the onset of luteal activity, and that decreasing the severity of negative energy balance in the early postcalving period would improve reproductive parameters. Nutritional regimens aimed at improving fertility were applied to 96 Holstein-Friesian dairy animals. Upon calving, animals were allocated in a balanced manner to one of 4 dietary treatments. Primiparous animals were balanced according to live weight, body condition score and calving date. Multiparous animals were balanced according to parity, previous lactation milk yield, liveweight, body condition score and calving date. Treatment 1 was based on an industry best practice diet (control) to contain 170 g of crude protein/kg of dry matter. Treatment 2 was an individual cow feeding strategy, whereby the energy balance (EB) of individual animals was managed so as to achieve a predetermined target daily EB profile (+/- 10 MJ/d). Treatment 3 was a high-starch/high-fat combination treatment, whereby an insulinogenic (high-starch) diet was offered in early lactation to encourage cyclicity and followed by a lipogenic (low-starch, high-fat) diet to promote embryo development. Treatment 4 was a low-protein diet, containing 140 g of crude protein/kg of dry matter, supplemented with protected methionine at an inclusion level of 40 g per animal per day. The nutritional strategies implemented in this study had no statistically significant effects on cow fertility measures, which included the onset of luteal activity, conception rate, in-calf rate, and the incidence of atypical cycles. The individual cow feeding strategy improved EB in early lactation but had no benefit on conception rate to first insemination. However, conception rate to second insemination, 100-d pregnancy rate (from the commencement of breeding), and overall pregnancy rate tended to be higher in this group. The high-starch/high-fat treatment tended to decrease the proportion of delayed ovulations and increase the proportion of animals cycling by d 50 postcalving. Animals that failed to conceive to first insemination had a significantly longer luteal phase in the first cycle postpartum and a longer inter-ovulatory interval in the second cycle postpartum. With regards to estrous behavior, results indicate that as the size of the sexually active group increased, the intensity of estrus and the expression of mounting or attempting to mount another cow also increased. Furthermore, cows that became pregnant displayed more intense estrous behavior than cows that failed to become pregnant.
Resumo:
A rapid liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the simultaneous identification, confirmation and quantitation of seven licensed anti-inflammatory drugs (AIDS) in bovine milk. The method was validated in accordance with the criteria defined in Commission Decision 2002/657/EC. Two classes of AIDS were investigated, corticosteroids and non-steroidal anti-inflammatory drugs (NSAIDs). The developed method is capable of detecting and confirming dexamethasone (DXM), betamethasone (BTM), prednisolone (FRED), tolfenamic acid (TV), 5-hydroxy flunixin (5-OH-FLU). meloxicam (MLX) and 4-methyl amino antipyrine (4-MAA) at their associated maximum residue limits (MRLs). These compounds represent all the corticosteroids and NSAIDs licensed for use in bovine animals producing milk for human consumption. These compounds have never been analysed before in the same method and also 4-methyl amino antipyrine has never been analysed with the other licensed NSAIDs. The method can be considered rapid as permits the analysis of up to 30 samples in one day. Milk samples are extracted with acetonitrile; sodium chloride is added to aid partition of the milk and acetonitrile mixture. The acetonitrile extract is then subjected to liquid-liquid purification by the addition of hexane. The purified extract is finally evaporated to dryness and reconstituted in a water/acetonitrile mixture and determination is carried out by LC-MS/MS. Decision limit (CC alpha) values and detection capability (CC beta) values have been established for each compound. (C) 2009 Elsevier B.V. All rights reserved.
Resumo:
Quantitative measurement of the activity of photoactive films is an area of importance. The establishment of tests for standardisation of performance is important for efficient research but also a major milestone in achieving technology acceptance. In this paper, we compare three different techniques across a range of film samples from various sources. Furthermore, we demonstrate the potential of the dye-based approach as a quick and simple test. A series of photoactive film samples are compared for measured activity against each test. The test is shown to be capable of reproducible and quantitative activity results. The test has potential for use
Resumo:
Background: Despite differences in how it is defined, there is a general consensus amongst clinicians and researchers that the sexual abuse of children and adolescents (’child sexual abuse’) is a substantial social problem worldwide. The effects of sexual abuse manifest in a wide range of symptoms, including fear, anxiety, post-traumatic stress disorder and various externalising and internalising behaviour problems, such as inappropriate sexual behaviours. Child sexual abuse is associated with increased risk of psychological problems in adulthood. Cognitive-behavioural approaches are used to help children and their non-offending or ’safe’ parent tomanage the sequelae of childhood sexual abuse. This review updates the first Cochrane review of cognitive-behavioural approaches interventions for children who have been sexually abused, which was first published in 2006.
Objectives: To assess the efficacy of cognitive-behavioural approaches (CBT) in addressing the immediate and longer-term sequelae of sexual abuse on children and young people up to 18 years of age.
Search methods: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2011 Issue 4); MEDLINE (1950 to November Week
3 2011); EMBASE (1980 to Week 47 2011); CINAHL (1937 to 2 December 2011); PsycINFO (1887 to November Week 5 2011); LILACS (1982 to 2 December 2011) and OpenGrey, previously OpenSIGLE (1980 to 2 December 2011). For this update we also searched ClinicalTrials.gov and the International Clinical Trials Registry Platform (ICTRP).
Selection criteria: We included randomised or quasi-randomised controlled trials of CBT used with children and adolescents up to age 18 years who had experienced being sexually abused, compared with treatment as usual, with or without placebo control.
Data collection and analysis: At least two review authors independently assessed the eligibility of titles and abstracts identified in the search. Two review authors independently extracted data from included studies and entered these into Review Manager 5 software. We synthesised and presented data in both written and graphical form (forest plots).
Main results: We included 10 trials, involving 847 participants. All studies examined CBT programmes provided to children or children and a nonoffending parent. Control groups included wait list controls (n = 1) or treatment as usual (n = 9). Treatment as usual was, for the most part, supportive, unstructured psychotherapy. Generally the reporting of studies was poor. Only four studies were judged ’low risk of bias’ with regards to sequence generation and only one study was judged ’low risk of bias’ in relation to allocation concealment. All studies were judged ’high risk of bias’ in relation to the blinding of outcome assessors or personnel; most studies did not report on these, or other issues of bias. Most studies reported results for study completers rather than for those recruited.
Depression, post-traumatic stress disorder (PTSD), anxiety and child behaviour problems were the primary outcomes. Data suggest that CBT may have a positive impact on the sequelae of child sexual abuse, but most results were not statistically significant. Strongest evidence for positive effects of CBT appears to be in reducing PTSD and anxiety symptoms, but even in these areas effects tend to be 'moderate’ at best. Meta-analysis of data from five studies suggested an average decrease of 1.9 points on the Child Depression Inventory immediately after intervention (95% confidence interval (CI) decrease of 4.0 to increase of 0.4; I2 = 53%; P value for heterogeneity = 0.08), representing a small to moderate effect size. Data from six studies yielded an average decrease of 0.44 standard deviations on a variety of child post-traumatic stress disorder scales (95% CI 0.16 to 0.73; I2 = 46%; P value for heterogeneity = 0.10). Combined data from five studies yielded an average decrease of 0.23 standard deviations on various child anxiety scales (95% CI 0.3 to 0.4; I2=0%; P value for heterogeneity = 0.84). No study reported adverse effects.
Authors’ conclusions: The conclusions of this updated review remain the same as those when it was first published. The review confirms the potential of CBT to address the adverse consequences of child sexual abuse, but highlights the limitations of the evidence base and the need for more carefully conducted and better reported trials.
Resumo:
True random number generation is crucial in hardware security applications. Proposed is a voltage-controlled true random number generator that is inherently field-programmable. This facilitates increased entropy as a randomness source because there is more than one configuration state which lends itself to more compact and low-power architectures. It is evaluated through electrical characterisation and statistically through industry-standard randomness tests. To the best of the author's knowledge, it is one of the most efficient designs to date with respect to hardware design metrics.
Resumo:
Background: This follow-up study aims to determine the physical parameters which govern the differential radiosensitization capacity of two tumor cell lines and one immortalized normal cell line to 1.9 nm gold nanoparticles. In addition to comparing the uptake potential, localization, and cytotoxicity of 1.9 nm gold nanoparticles, the current study also draws on comparisons between nanoparticle size and total nanoparticle uptake based on previously published data.
Methods: We quantified gold nanoparticle uptake using atomic emission spectroscopy and imaged intracellular localization by transmission electron microscopy. Cell growth delay and clonogenic assays were used to determine cytotoxicity and radiosensitization potential, respectively. Mechanistic data were obtained by Western blot, flow cytometry, and assays for reactive oxygen species.
Results: Gold nanoparticle uptake was preferentially observed in tumor cells, resulting in an increased expression of cleaved caspase proteins and an accumulation of cells in sub G1 phase. Despite this, gold nanoparticle cytotoxicity remained low, with immortalized normal cells exhibiting an LD50 concentration approximately 14 times higher than tumor cells. The surviving fraction for gold nanoparticle-treated cells at 3 Gy compared with that of untreated control cells indicated a strong dependence on cell type in respect to radiosensitization potential.
Conclusion: Gold nanoparticles were most avidly endocytosed and localized within cytoplasmic vesicles during the first 6 hours of exposure. The lack of significant cytotoxicity in the absence of radiation, and the generation of gold nanoparticle-induced reactive oxygen species provide a potential mechanism for previously reported radiosensitization at megavoltage energies.