There have been a number of previous estimates of human inbreeding for Britons of British descent in Britain, each generally for different social classes, geographical regions, and/or time periods. In this study I attempted to collect all relevant published studies and combine these disparate results into an integrated whole for all of Britain. This was achieved by combining weighted means of the percentage of consanguineous marriages (f%) reported in these earlier studies: weighted according to the number of records each author examined, the proportion of social classes or geographic regions covered by the records, and the "merit" of their individual research methodologies. The percentage occurrences of the various consanguineous marriages, from first to third cousins, were partitioned into a number of time periods, which allowed the weighted mean percentage inbreeding coefficients (F%) to be obtained as a function of time over the period from 1820 to 1960. The resulting temporal scatter distribution of the weighted F% values closely followed a sigmoidal curve, with a nonlinear correlation coefficient of η = 0.974, which fitted well to a generalized logistic function. After about 1900 the value of the weighted F% was essentially constant at about 0.038 ± 0.004, whereas it decreased rapidly from about 0.256 ± 0.011 between 1820 and 1900. The upper-bound value of weighted F% before 1820 from the fitted logistic function is 0.276. This corresponds to a value of the conventional mean inbreeding coefficient F = 0.00276. As the first known attempt to integrate the earlier disparate values of unweighted F% for Britons of British descent for all of Britain, the results of this analysis are promising and should be useful as reference values in other related studies.

The minimal dose covering 90 % of the prostate volume-D (90)-is arguably the most important dosimetric parameter in low-dose-rate prostate seed brachytherapy. In this study an analysis of the measurement uncertainties in D (90) from low-dose-rate prostate seed brachytherapy was conducted for two common treatment procedures with two different post-implant dosimetry methods. The analysis was undertaken in order to determine the magnitude of D (90) uncertainty, how the magnitude of the uncertainty varied when D (90) was calculated using different dosimetry methods, and which factors were the major contributors to the uncertainty. The analysis considered the prostate as being homogeneous and tissue equivalent and made use of published data, as well as original data collected specifically for this analysis, and was performed according to the Guide to the expression of uncertainty in measurement (GUM). It was found that when prostate imaging and seed implantation were conducted in two separate sessions using only CT images for post-implant analysis, the expanded uncertainty in D (90) values were about 25 % at the 95 % confidence interval. When prostate imaging and seed implantation were conducted during a single session using CT and ultrasound images for post-implant analysis, the expanded uncertainty in D (90) values were about 33 %. Methods for reducing these uncertainty levels are discussed. It was found that variations in contouring the target tissue made the largest contribution to D (90) uncertainty, while the uncertainty in seed source strength made only a small contribution. It is important that clinicians appreciate the overall magnitude of D (90) uncertainty and understand the factors that affect it so that clinical decisions are soundly based, and resources are appropriately allocated.

In this study, some characteristics of the photo-electrons produced when natural background gamma radiation interacts with micron-sized depleted uranium (DU) particles in the human body have been estimated using Monte Carlo simulations. In addition, an estimate has been made of the likelihood of radiological health effects occurring due to such an exposure. Upon exposure to naturally occurring background gamma radiation, DU particles in the body will produce an enhancement of the dose to the tissue in the immediate vicinity of the particles due to the photo-electric absorption of the radiation in the particle. In this study, the photo-electrons produced by a 10 μm-size particle embedded in tissue at the centre of the human torso have been investigated. The mean energies of the photo-electrons in the DU particle and in the two consecutive immediately surrounding 2 μm-wide tissue shells around the particle were found to be 38, 49 and 50 keV, respectively, with corresponding ranges of 1.3, 38 and 39 μm, respectively. The total photo-electron fluence-rates in the two consecutive 2 μm-wide tissue layers were found to be 14% and 7% of the fluence-rate in the DU particle, respectively. The estimated dose enhancement due to one 10 μm-sized DU particle in 1 cm(3) of tissue was less than 2 in 10 million of the dose received by the tissue without a particle being present. The increase in risk of death from cancer due to this effect is consequently insignificant.

The genetic surveys of the population of Britain conducted by Weale et al. and Capelli et al. produced estimates of the Germani immigration into Britain during the early Anglo-Saxon period, c.430-c.730. These estimates are considerably higher than the estimates of archaeologists. A possible explanation suggests that an apartheid-like social system existed in the early Anglo-Saxon kingdoms resulting in the Germani breeding more quickly than the Britons. Thomas et al. attempted to model this suggestion and showed that it was a possible explanation if all Anglo-Saxon kingdoms had such a system for up to 400 years. I noted that their explanation ignored the probability that Germani have been arriving in Britain for at least the past three millennia, including Belgae and Roman soldiers, and not only during the early Anglo-Saxon period. I produced a population model for Britain taking into account this long term, low level migration that showed that the estimates could be reconciled without the need for introducing an apartheid-like system. In turn, Thomas et al. responded, criticizing my model and arguments, which they considered persuasively written but wanting in terms of methodology, data sources, underlying assumptions, and application. Here, I respond in detail to those criticisms and argue that it is still unnecessary to introduce an apartheid-like system in order to reconcile the different estimates of Germani arrivals. A point of confusion is that geneticists are interested in ancestry, while archaeologists are interested in ethnicity: it is the bones, not the burial rites, which are important in the present context.

Microarray technology has revolutionized biomedical research because it is now possible to concurrently determine the gene expression levels for the whole genome of a target organism. The accuracy of the computed gene expression levels is extremely important for the successful use of this technology. However, microarray gene expression measurements are inherently very 'noisy', meaning that appropriate techniques are required to compute accurate gene expression levels. Therefore, the pre-processing of microarray data warrants special consideration. Although there are many candidate techniques for the pre-processing of microarray data, there is no clear-cut best option. In this review, we discuss some of the most important pre-processing techniques applicable to the Affymetrix microarray platform. We also discuss the problems involved in evaluating the different candidate techniques and consider other crucial issues related to the pre-processing of Affymetrix microarray data.

An infrared (IR) camera is one of the common tools for taking images for thermography analysis in the medical field. In this paper, object recognition using infrared images captured with a Middle Wave Infrared (MWIR) camera is studied. By using the InSb detector, the MWIR system used in this study operates in the 3−5 μm waveband, and it is suited for high-end research and development applications. To enhance the use of MWIR thermography in real-world applications, it is important to devise reliable image generation and processing techniques for MWIR images. An experimental study has been conducted to identify the capability of MWIR thermography in distinguishing an object (a human hand) from its background with varying emissivity and temperature levels. It was observed that object recognition becomes difficult when the emissivity difference is within 0.01 under the temperature condition of within 1°C for the object and the background.

An infrared (IR) camera is one of the common tools for taking images for thermography analysis in the medical field. In this paper, object recognition using infrared images captured with a middle wave infrared (MWIR) camera is studied. By using the InSb detector, the MWIR system used in this study operates in the 3-5 μm waveband, and it is well-suited for highend research and development applications. To enhance the applicability of MWIR thermography to medical-related problems, it is important to devise reliable recognition and enhancement techniques for MWIR images. In this work, an experimental study is conducted to identify the capability of MWIR thermography in distinguishing an object (a human hand) from its background with varying emissivity and temperature levels. It is observed that object recognition becomes difficult when the emissivity difference is within 0.01 under the temperature condition of within 1°C for the object and the background. In addition, a histogram equalisation approach is utilised to enhance blurry images from the MWIR system. The results demonstrate the histogram equalisation method is able to expand the dynamic range expansion of image grey levels so that the output image becomes clear and visible for object recognition.

Scene understanding is an essential element for the exploration of unknown territory using mobile robots. In this regard, scene understanding refers to the identification and localization of elements within the scene. When the scene is dynamic or has objects that move around, they need to be characterized and discriminated from the static elements, which are essential for SLAM (Simultaneous Localization And Mapping) when external or global localization information is not available. We present techniques and algorithms to accomplish these goals with regard to a scenario where we have a co-operative of robots having three degrees of freedom (x, y, t) and equipped with a fixed monocular camera, observing a dynamic scene. The strategy is to localize the static elements of the scene and then estimate the velocity and trajectory of moving objects. The latter is much more difficult to solve than the former. We also present co-ordination and steering strategies for reducing the errors associated with the estimated parameters.

Ongoing controversy surrounds the adverse health effects of the use of depleted uranium (DU) munitions. The biological effects of gamma-radiation arise from the direct or indirect interaction between secondary electrons and the DNA of living cells. The probability of the absorption of X-rays and gamma-rays with energies below about 200 keV by particles of high atomic number is proportional to the third to fourth power of the atomic number. In such a case, the more heavily ionizing low-energy recoil electrons are preferentially produced; these cause dose enhancement in the immediate vicinity of the particles. It has been claimed that upon exposure to naturally occurring background gamma-radiation, particles of DU in the human body would produce dose enhancement by a factor of 500–1000, thereby contributing a significant radiation dose in addition to the dose received from the inherent radioactivity of the DU. In this study, we used the Monte Carlo code EGSnrc to accurately estimate the likely maximum dose enhancement arising from the presence of micrometre-sized uranium particles in the body. We found that although the dose enhancement is significant, of the order of 1–10, it is considerably smaller than that suggested previously.

Scene understanding is an essential element involved in the exploration of an unknown environment when using mobile robots. In this regard, scene understanding refers to the identification and localization of elements in the scene. When the scene is dynamic. it has objects that move around and they need to he characterized and discriminated from the static elements. This is essential for the SLAM (Simultaneous Localization And Mapping) process when external global localization information is not available. We present some techniques and algorithms to accomplish these goals with regard to a scenario where we have a cooperative of robots each equipped with a monocular camera. The robots have three degrees of freedom (x,y,theta) and observe a dynamic scene. The objectives are to use the static elements of the scene for self-localization of robots and to estimate the velocity, trajectory and structure of any moving objects with a view to coordinating robot activity. We discuss several metrics for structure estimation that could be used or the co-ordination of robot manoeuvres and develop optimized steering mechanisms, which reduce the errors associated with estimating key parameters.

Purpose: This study is an extension of a previous study where the uncertainties in effective dose estimates from adult CT head scans were calculated using four CT effective dose estimation methods, three of which were computer programs (CT‐EXPO, CTDOSIMETRY, and IMPACTDOSE) and one that involved the dose length product (DLP). However, that study did not include the uncertainty contribution due to variations in head sizes.Methods: The uncertainties due to head size variations were estimated by first using the computer program data to calculate doses to small and large heads. These doses were then compared with doses calculated for the phantom heads used by the computer programs. An uncertainty was then assigned based on the difference between the small and large head doses and the doses of the phantom heads.Results: The uncertainties due to head size variations alone were found to be between 4% and 26% depending on the method used and the patient gender. When these uncertainties were included with the results of the previous study, the overall uncertainties in effective dose estimates (stated at the 95% confidence interval) were 20%–31% (CT‐EXPO), 15%–30% (CTDOSIMETRY), 20%–36% (IMPACTDOSE), and 31%–40% (DLP).Conclusions: For the computer programs, the lower overall uncertainties were still achieved when measured values of CT dose index were used rather than tabulated values. For DLP dose estimates, head size variations made the largest (for males) and second largest (for females) contributions to effective dose uncertainty. An improvement in the uncertainty of the DLP method dose estimates will be achieved if head size variation can be taken into account.

It has recently been argued that there was an apartheid-like social structure operating in Early Anglo-Saxon England. This was proposed in order to explain the relatively high degree of similarity between Germanic-speaking areas of northwest Europe and England. Opinions vary as to whether there was a substantial Germanic invasion or only a relatively small number arrived in Britain during this period. Contrary to the assumption of limited intermarriage made in the apartheid simulation, there is evidence that significant mixing of the British and Germanic peoples occurred, and that the early law codes, such as that of King Ine of Wessex, could have deliberately encouraged such mixing. More importantly, the simulation did not take into account any northwest European immigration that arrived both before and after the Early Anglo-Saxon period. In view of the uncertainty of the places of origin of the various Germanic peoples, and their numbers and dates of arrival, the present study adopts an alternative approach to estimate the percentage of indigenous Britons in the current British population. It was found unnecessary to introduce any special social structure among the diverse Anglo-Saxon people in order to account for the estimates of northwest European intrusion into the British population.

In this paper, we review modern nonlinear dynamical methods used in neuroscience and complex data analysis. We start with the general description of nonlinear dynamics, its geometrical (and topological) picture, as well as its extreme case, deterministic chaos, including its most popular models and methods: Lorenz attractor, Lyapunov exponents, and Kolmogorov–Sinai entropy.

In this report we review modern nonlinearity methods that can be used in the preterm birth analysis. The nonlinear analysis of uterine contraction signals can provide information regarding physiological changes during the menstrual cycle and pregnancy. This information can be used both for the preterm birth prediction and the preterm labor control. Keywords: preterm birth, complex data analysis, nonlinear methods

Estimates of the effective dose to adult patients from computed tomography (CT) head scanning can be calculated using a number of different methods. These estimates can be used for a variety of purposes, such as improving scanning protocols, comparing different CT imaging centers, and weighing the benefits of the scan against the risk of radiation-induced cancer. The question arises: What is the uncertainty in these effective dose estimates? This study calculates the uncertainty of effective dose estimates produced by three computer programs (CT-EXPO, CTDosimetry, and ImpactDose) and one method that makes use of dose-length product (DLP) values. Uncertainties were calculated in accordance with an internationally recognized uncertainty analysis guide. For each of the four methods, the smallest and largest overall uncertainties (stated at the 95% confidence interval) were: 20%-31% (CT-EXPO), 15%-28% (CTDosimetry), 20%-36% (ImpactDose), and 22%-32% (DLP), respectively. The overall uncertainties for each method vary due to differences in the uncertainties of factors used in each method. The smallest uncertainties apply when the CT dose index for the scanner has been measured using a calibrated pencil ionization chamber.

The purpose of the study reported here was to investigate two important assumptions used in a recently reported new method of estimating inbreeding in large, relatively isolated populations over historic times. The method, based on modeling the genealogical “paradox,” produces values of Pearl's coefficients, Z , a measure of inbreeding or genealogical coalescence, as a function of time. In this study, the effects on inbreeding of two important assumptions made in earlier studies, namely those of using a constant generation length and of ignoring migration, have been investigated for the population of Britain. First, by relating the median age of women at childbirth to the development level of various societies, the variation of the generation lengths for different periods in historic Britain were estimated. Values of Z for two types of varying generation lengths were then calculated and compared with the case of constant generation length. Second, the population curve for Britain used in earlier studies was modified to obtain the subpopulation at any time during the past two millennia that was descended from the pre‐Roman British Celts. Values of Z for the case with migration were then calculated and compared with the case for no migration. It is shown that these two assumptions may be taken into account if and when required. Both the effect of a varying generation length and the effect of migration on Z were found to be 20–40%, when no known value of inbreeding was used, and 2–5%, when a known value of inbreeding was used. Am. J. Hum. Biol. 19:495–510, 2007. © 2007 Wiley‐Liss, Inc.

The general purpose Monte Carlo code PENELOPE is used to calculate microdosimetric quantities including dose-weighted lineal energy spectra, which can be used to predict relative biological effect (RBE), for binary radiation therapies that utilise the photoabsorption of X-ray of high-Z materials. Spectra are calculated for Gd homogenously distributed at a concentration of 10mg/ml in water and irradiated by 70keV monoenergetic photons, around 20keV above the k-edge of Gd (50.239keV), which has been shown to give optimal dose enhancement, and for a metallic Gd surface in close proximity (within 2μm) to a sensitive component of the nucleosome, modelled as a sphere of water of 1μm diameter, for 60 and 70keV monoenergetic X-rays. X-ray interactions with homogenously distributed Gd lead to a greater population of high lineal energy electrons than in liquid water, probably due to the creation of short range Auger electrons and photoelectrons, whereas interactions with Gd outside of the sensitive volume are longer ranged increasing the population of low lineal energy electrons. The data does not support increased therapeutic advantage through increased RBE in the case of Gd bearing contrast systems where little cellular absorption of Gd occurs. Homogenously distributed Gd leads to higher lineal energies than pure water, probably due to the creation of short range, high LET Auger and photoelectrons, whereas photoelectrons that originate in Gd that are outside the sensitive volume tend to have relatively higher energies and long ranges increasing the population of low LET electrons.