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Background: Recurrence of chronic subdural haematomas (CSDHs) after surgical drainage is a significant problem with rates up to 20%. This study focuses on determining factors predictive of haematoma recurrence and presents a scoring system stratifying recurrence risk for individual patients. Methods: Between the years 2005 and 2009, 331 consecutive patients with CSDHs treated with surgery were included in this study. Univariate and multivariate analyses were performed searching for risk factors of increased post-operative haematoma volume and haematoma recurrence requiring repeat drainage. Results: We found a 12% reoperation rate. CSDH septation (seen on computed tomogram scan) was found to be an independent risk factor for recurrence requiring reoperation (p=0.04). Larger post-operative subdural haematoma volume was also significantly associated with requiring a second drainage procedure (p<0.001). Independent risk factors of larger post-operative haematoma volume included septations within a CSDH (p<0.01), increased pre-operative haematoma volume (p<0.01), and a greater amount of parenchymal atrophy (p=0.04). A simple scoring system for quantifying recurrence risk was created and validated based on patient age (< or ≥80 years), haematoma volume (< or ≥160cc), and presence of septations within the subdural collection (yes or no). Conclusion: Septations within CSDHs are associated with larger post-operative residual haematoma collections requiring repeat drainage. When septations are clearly visible within a CSDH, craniotomy might be more suitable as a primary procedure as it allows greater access to a septated subdural collection. Our proposed scoring system combining haematoma volume, age, and presence of septations might be useful in identifying patients at higher risk for recurrence.
Earlier age of menarche is believed to confer greater vulnerability to depressive symptoms via increased reactivity to stressors associated with adolescence. In this longitudinal study, we measured depressive symptoms and salivary cortisol levels in 198 boys and 142 girls between the ages of 11 and 13 tested four times during Grade 7 as they transitioned from elementary school to secondary school as per Quebec's education system. Results showed that girls who had already reached menarche before starting secondary school had significantly higher depressive symptoms and salivary cortisol levels across the school year in comparison to girls who had not reached menarche, who in turn presented higher depressive scores than boys. When we divided menarcheal girls as a function of menarcheal timing in subanalyses, we found that girls with early menarche presented consistently elevated depressive symptoms across the school year while girls with on-time menarche presented transient depressive symptoms but no differences in salivary cortisol levels. Collectively, these results show that early menarche is associated with high depressive symptoms and cortisol levels in adolescent girls. This developmental milestone may render girls more vulnerable to environmental stressors and therefore represents a critical period to intervene to promote mental health.
One of the difficulties in analyzing atomic resolution electron microscope images is that the sample thickness is usually unknown or has to be fitted from parameters that are not precisely known. An accurate measure of thickness, ideally on a column-by-column basis, parameter free, and with single atom accuracy, would be of great value for many applications, such as matching to simulations. Here we propose such a quantification method for annular dark field scanning transmission electron microscopy by using the single electron intensity level of the detector. This method has the advantage that we can routinely quantify annular dark field images operating at both low and high beam currents, and under high dynamic range conditions, which is useful for the quantification of ultra-thin or light-element materials. To facilitate atom counting at the atomic scale we use the mean intensity in an annular dark field image averaged over a primitive cell, with no free parameters to be fitted. To illustrate the potential of our method, we demonstrate counting the number of Al (or N) atoms in a wurtzite-type aluminum nitride single crystal at each primitive cell over the range of 3–99 atoms.
In-line monitoring of the electrical properties of high-k dielectrics in logic or memory fab-lines has become increasingly important in the semiconductor industry. Non-contact corona-Kelvin based metrology can be used to affectively monitor in-line key dielectric properties. Furthermore, we present an important extension of this metrology to the micro-scale that allows measurement of dielectric properties on test sites as small as 40μm × 70μm. This is achieved through miniaturization of the corona charging apparatus and of the Kelvin probe without a sacrifice in precision or repeatability. Corona-Kelvin micro-metrology allows for the monitoring of the critical dielectric properties directly on product wafers that can then be returned to the fab-line for continued processing. Application examples are given for dielectric capacitance of advanced dielectrics and for the properties of an oxide-nitride-oxide (ONO) memory structure. In the latter case we demonstrate programming and erasing of the ONO structure realized by corona charging. We also use the measured flatband voltage and total charge to identify the location of the programmed charge at the first SiO2/Si3N4 interface in the ONO structure.
The First Access for Shock and Trauma (FAST 1) Sternal Intraosseous (IO) System is a vascular access device designed as an alternative to peripheral or central intravenous (IV) cannulation for the treatment of critically ill and injured adults. During the development of the device, key objectives included safety, speed of insertion, and ease of use with minimal training. This study evaluated these characteristics.
Ten experienced paramedics participated in a 90-minute training program for the use of the FAST 1 System at the Paramedic Academy of the Justice Institute of British Columbia. Then, the paramedics used thesystem in three simulated prehospital scenarios and evaluated the ease of use and compatibility of the training method with current practice using a 10-centimeter (cm) (3.94 inches (in)), visual analog scale.
The duration of the procedure from opening the package to initiation of fluid flow ranged 52–127 seconds (mean = 92 ±32 seconds). Placement accuracy was excellent, with a mean displacement of 2 mm (0.08 in) and 1 mm (0.04 in) in the vertical and horizontal planes, respectively. The paramedics rated the system highly in all areas. They considered the training “straight forward” and “comprehensive”. The possibility for interference between the IO system and cervical collars was reported, and several suggestions to remedy this and achieve other improvements were made.
Placement of the FAST 1 is fast, accurate, and easy to use. Paramedics had useful input concerning the design of the product.
In an article published in Microscopy and Microanalysis
recently (Jia et al., 2004), it was claimed
that aberration-corrected high resolution transmission electron
microscopy (HRTEM) allows the quantitative measurement of oxygen
concentrations in ceramic materials with atomic resolution. Similar
claims have recently appeared elsewhere, based on images obtained
through aberration correction (Jia et al.,
2003; Jia & Urban, 2004) or very
high voltages (Zhang et al., 2003). Seeing
oxygen columns is a significant achievement of great importance (Spence, 2003) that will doubtlessly allow some
exciting new science; however, other models could provide a better
explanation for some of the experimental data than variations in the
oxygen concentration. Quantification of the oxygen concentrations was
attempted by comparing experimental images with simulations in which
the fractional occupancy in individual oxygen columns was reduced. The
results were interpreted as representing nonstoichiometry within the
bulk and at grain boundaries. This is plausible because previous
studies have shown that grain boundaries can be nonstoichiometric
(Kim et al., 2001), and it is indeed possible
that oxygen vacancies are present at boundaries or in the bulk.
However, is this the only possible interpretation? We show
that for the thicknesses considered a better match to the images is
obtained using a simple model of surface damage in which atoms are
removed from the surface, which would usually be interpreted as surface
damage or local thickness variation (from ion milling, for example).
Over the past ten years, the development of rural manufacturing, handicraft and commercial enterprises has become one of the cornerstones of China's economic reform policies. This process has absorbed surplus agricultural labour, raised incomes and transformed the structure of the rural economy. As a result, the Chinese countryside is embarking on a phase of development that is bringing an end to the economic dominance of agriculture. With the increasing commercialisation of rural production, growth of rural enterprises has accelerated the pace of urbanisation, playing a key role in a number of fundamental economic processes. The significance of the economic changes involved cannot be overstated.
Why has it been rural industry which has grown so rapidly? Reform and growth are likely to lead to economic transformation and a relative decline in the agricultural sector. But there are no expectations in this analytical structure about the location of industrial growth. Will it occur more rapidly in rural areas or in urban areas? One of our aims is to explain why industrialisation in China has had a rural bias.
The growth of rural industry has transformed the relationship between town and countryside and created some tensions in relations between the urban and rural economies. The growth of rural industry and the associated transformation has been greatest in the coastal provinces, especially from Hainan to Jiangsu, north of Shanghai, but its effects have been felt throughout the country.
Grain transfer between provinces and regions has long been a major issue in China's agricultural policy (Lardy 1990). Grain has to be transferred from the major producing areas to the large urban centres and it has always been necessary to adjust for varietal composition in regional supplies and to compensate for the vagaries of weather and local fluctuations in output. The appropriate balance between grain for human consumption and for animals has been an important issue with priority consistently given to human consumption.
Since 1978, the structure of grain production, pricing and marketing has passed through several phases of reform (Lin, chapter 2; Huang, chapter 3). Economic growth, by transforming both demand and supply, has added a different dimension of change. In terms of demand, increases in income have encouraged a change in consumer's diets (Garnaut and Ma, chapter 4). As a consequence, the proportion of grain consumed directly is declining and that consumed through animal products is increasing. This change has consequences for both regional transfers within China and for the structure of China's international grain trade.
In terms of supply, peasant households are now sharply aware of their opportunity costs. Fluctuations in grain production since 1984 have, in part, reflected producer's desire to move to higher-value crops. The management of grain production now has to take into account producer incentives, and, given the problems of handling this issue successfully in a semi-reformed economy, it is not surprising, after a brief period of relaxation, that governments throughout China in the late 1980s again shifted towards greater coercion in grain production through the system of fixed contracts.
Textile fibres are at once a major source of farm output and income (ranking after grain), and a major input into industrial production (ranking after coal and oil). The textile industries have contributed the largest component of the increase in industrial production in both urban and rural areas since the commencement of reform. Production, trade and utilisation of natural textiles is thus an important part of the story of the Chinese rural economy in the reform period, interacting with agriculture, rural industry, trade between rural and urban areas, and economic exchange between the farms and township and village enterprises.
A study of the production, trade and absorption of natural textile fibres illustrates many of the problems and contradictions of China's partially reformed economic system. Nowhere were the contradictions more costly, or revealed more dramatically, than in the struggle that emerged in the late 1980s for possession of the rents generated by controlled and distorted markets for natural fibres. These came to be known in China as the ‘wool war’ and the ‘cotton chaos’.
A highly competitive and internationally oriented processing industry co-existed alongside problems in the supply of raw material. Constraints on local production of raw materials were not the problem, as natural fibres are internationally tradable, and the textiles and clothing sector has been a net importer of raw materials. Access to the world market permits a separation between the fibre production stage and the processing stage.
The absence of a systematic programme has been a distinctive feature of China's economic reform process. The Chinese did not set out to develop a step-by-step plan of reform to be phased in over a period of years. Instead they adopted a number of strategic goals, and in 1978 launched incremental and pragmatic changes aimed at realizing them. Essentially the strategy adopted had four main aspects: a shift from economic growth expressed mainly through statistical targets towards an emphasis on satisfying the consumption needs of the population; a change from extensive development based on new investment towards intensive development through greater efficiency; an acceptance of greater economic autonomy for producers, with a broader mix of methods of economic management and types of ownership; and the adoption of a much more open economy. The reforms adopted over the succeeding years have all been consistent with these objectives, but they have not been implemented through a carefully planned series of stages. Overall the process has been marked by different rates of reform across sectors, by occasional pauses and even retreats, and by problems generated by the interaction of the differing rates of reform. Enterprise managers, for example, have found that plan controls over their production or sales have disappeared at a faster rate than controls over their supply of inputs. Given the dual price system and the continuing role of the central government in the supply of strategic materials and energy, the impact of the uneven pace of change on managers’ behaviour has therefore been very complex.
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