252 research outputs found

    Reading between the lines: railways and popular fiction in late nineteenth-century Britain

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    This study comprises an analysis of popular nineteenth-century fiction aimed at the family reader and featuring the railways, to ascertain how the railways impacted on community structures and how these changes manifested in literature. The primary texts featured are Robert Ballantyne’s The iron horse; Mary Leith’s Mark Dennis; Emma Leslie’s Gerald’s dilemma and Maggie’s message; Elton Keane’s Heroes of the railway; and Sabine Baring-Gould’s The Pennycomequicks. Furthermore, this study specifically looks at representations of the engine-driver as a public hero and the effects this had on their families; the railway passenger’s response to danger and the discrepancy between private and public liability for risk; and the presentation of the railway-carriage as a space of possibility in which new modes of being could be formed. The primary texts in this study have been chosen as they are all in some way about, or feature, the railways of the late nineteenth-century in a manner that proves the importance the railways had in shaping networks of mobility, but that also highlight the important role popular fiction had in conditioning readers to reconcile the dangers of railway travel with the opportunities that were afforded by them

    Taking Root: An Analysis of the Best Method for Active Forest Regeneration in the Cloud Forest

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    The cloud forest is a biodiversity hotspot and provides many vital ecological and economic services. Unfortunately, deforestation for pastures in the lower montane cloud forest is high. Many pastures become abandoned, leaving highly disturbed open areas of land where natural forest regeneration is poor. Human intervention to encourage ecological restoration is very important to re-establish the proper structure and functioning of the ecosystem. Forest regeneration projects are rare and often unsuccessful, which is why increased knowledge and skills of successful and practical methods for assisted regeneration are needed. The Inti Llacta Reserve in the Pichincha province in Ecuador protects a biodiverse area of cloud forest and is dedicated to sustainable land practices, including restoration of retired pasture. This study compares different restoration methods on the reserve to determine the most successful treatment to facilitate natural forest regeneration. Four different areas of retied pasture undergoing early secondary succession were surveyed: an active experiment with grass eradication where key pioneer, coloniser, and climax species were planted; an area where Aliso trees were planted five years ago; an area where Tithonia bushes were planted seven years ago, and an area of passive regeneration. Successful regeneration was expected to occur in areas with low invasive grass cover and high seed rain. The results show that the active experiment had the highest density of regenerated species despite the highest grass cover. Seed input from established plants or from the forest was an important factor for success in this site. Shade was most successful in reducing grass cover but natural regeneration was slow, so another type of intervention to reduce grass cover is needed to speed up regeneration. Resumen El bosque nublado es un área lleno de biodiversidad y provee muchos servicios vitales para la ecología y la economía. Desafortunadamente, la deforestación para las pasturas en el bosque nublado es alta. Muchas pasturas son abandonadas, dejando áreas abiertas de la tierra muy degradadas en donde la regeneración natural del bosque es pobre. La intervención humana para estimular la restauración ecológica es muy importante para restablecer la estructura y función correcta del ecosistema. Proyectos del regeneración del bosque son raros y a menudo no tienen éxito, y por eso es necesario aumentar el saber y las habilidades de métodos éxitos y prácticos para la regeneración asistida. La Reserva Inti Llacta en la provincia Pichincha en Ecuador protege un área del bosque nublado biodiversa y está dedicando a los prácticos sustentables, incluyendo la restauración de las pasturas retiradas. Este estudio compara diferentes métodos de restauración en la reserva para determinar el método más exitoso para facilitar la regeneración natural del bosque. Cuatro áreas diferentes de pastura retirada en proceso del inicio de sucesión secundaria estaban evaluados: un experimento activo con erradicación del pasto y especies claves sembradas de tipo pionera, colonizador, y clímax; un área con alisos sembrados hace cinco años; un área con arbustos de Tithonia sembrados hace siete años, y un área de regeneración pasiva. Había supuesto que regeneración exitosa ocurría en áreas bajas en cobertura de pasto y altas en la lluvia de semillas. Los resultados muestran que el experimento activo tenía la densidad de especies regeneradas más alta a pesar de tener la cobertura de pasto más alta. La contribución de semillas de las plantas establecidas o del bosque fue un factor importante para el éxito de regeneración en este sitio. La sombra tenía el más éxito en reducir la cobertura de pasto, pero la regeneración natural fue lenta, entonces otro tipo de intervención es necesario para reducir la cobertura de pasto y apurar la regeneración

    Pendulum Mode Thermal Noise in Advanced Interferometers: A comparison of Fused Silica Fibers and Ribbons in the Presence of Surface Loss

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    The use of fused-silica ribbons as suspensions in gravitational wave interferometers can result in significant improvements in pendulum mode thermal noise. Surface loss sets a lower bound to the level of noise achievable, at what level depends on the dissipation depth and other physical parameters. For LIGO II, the high breaking strength of pristine fused silica filaments, the correct choice of ribbon aspect ratio (to minimize thermoelastic damping), and low dissipation depth combined with the other achievable parameters can reduce the pendulum mode thermal noise in a ribbon suspension well below the radiation pressure noise. Despite producing higher levels of pendulum mode thermal noise, cylindrical fiber suspensions provide an acceptable alternative for LIGO II, should unforeseen problems with ribbon suspensions arise.Comment: Submitted to Physics Letters A (Dec. 14, 1999). Resubmitted to Physics Letters A (Apr. 3, 2000) after internal (LSC) review process. PACS - 04.80.Nn, 95.55.Ym, 05.40.C

    Comparison of resting-state EEG between adults with Down syndrome and typically developing controls

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    Background: Down syndrome (DS) is the most common genetic cause of intellectual disability (ID) worldwide. Understanding electrophysiological characteristics associated with DS provides potential mechanistic insights into ID, helping inform biomarkers and targets for intervention. Currently, electrophysiological characteristics associated with DS remain unclear due to methodological differences between studies and inadequate controls for cognitive decline as a potential cofounder. Methods: Eyes-closed resting-state EEG measures (specifically delta, theta, alpha, and beta absolute and relative powers, and alpha peak amplitude, frequency and frequency variance) in occipital and frontal regions were compared between adults with DS (with no diagnosis of dementia or evidence of cognitive decline) and typically developing (TD) matched controls (n = 25 per group). Results: We report an overall ‘slower’ EEG spectrum, characterised by higher delta and theta power, and lower alpha and beta power, for both regions in people with DS. Alpha activity in particular showed strong group differences, including lower power, lower peak amplitude and greater peak frequency variance in people with DS. Conclusions: Such EEG ‘slowing’ has previously been associated with cognitive decline in both DS and TD populations. These findings indicate the potential existence of a universal EEG signature of cognitive impairment, regardless of origin (neurodevelopmental or neurodegenerative), warranting further exploration

    Effect of Optical Coating and Surface Treatments on Mechanical Loss in Fused Silica

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    We report on the mechanical loss in fused silica samples with various surface treatments and compare them with samples having an optical coating. Mild surface treatments such as washing in detergent or acetone were not found to affect the mechanical loss of flame-drawn fused silica fibers stored in air. However, mechanical contact (with steel calipers) significantly increased the loss. The application of a high-reflective optical coating of the type used for the LIGO test masses was found to greatly increase the mechanical loss of commercially polished fused silica microscope slides. We discuss the implications for the noise budget of interferometers.Comment: 7 pages, 2 figures. Accepted for publication in the Proceedings of the Third Eduardo Amaldi Conference on Gravitational Waves, July 12-16, 1999. Updated version contains a correction of Eq. 3 and an estimate for the loss angle of a LIGO coating. (Neither of these revisions are included in the version published in the conference proceedings.

    Comparison of Receptive Verbal Abilities Assessed Using the KBIT-2 and BPVS3 in Adults With Down Syndrome

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    Down syndrome (DS) is the most common genetic cause of intellectual disability. There is, however, considerable variation in cognitive abilities between those with DS, with some individuals scoring at floor on some tests, particularly for age-standardised outcomes. This variation and these floor effects can pose a problem for comparing and combining study populations when different standardised measures have been used to assess individuals’ cognitive abilities, for example combining results across studies to investigate genetic or other factors associated with cognitive abilities. To facilitate this comparison and combination of study populations assessed using different tests of verbal abilities, we administered two commonly used standardised tests of receptive language, the Kaufmann Brief Intelligence Test 2 (KBIT-2) verbal scale and the British Picture Vocabulary Scale 3 (BPVS3) to 34 adults with DS (age range 19–59) to investigate relationships between outcomes for these two tests. We found a very strong correlation between raw scores for the KBIT-2 verbal scale and the BPVS3, and determined equations to convert between scores for the two tests. Intraclass correlations between the two scales for age-equivalents and calculated z scores relative to population norms were also strong, though scores for both outcomes were significantly higher for the KBIT-2 verbal scale compared to the BPVS3. This deviation in scores between the two tests was greater as z scores decreased for both tests (i.e., for lower scoring individuals), with no such relationship observed for age-equivalents. These results indicate the conversion of raw scores between the KBIT-2 verbal scale and the BPVS3 may be a more valid method for the comparison or combination of study samples with DS compared to the use of standardised scores. Such comparisons or combinations will aid our understanding of cognitive variations and factors associated with these variations within the population with DS

    Frequency and surface dependence of the mechanical loss in fused silica

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    We have compiled measurements of the mechanical loss in fused silica from samples spanning a wide range of geometries and resonant frequency in order to model the known variation of the loss with frequency and surface-to-volume ratio. This improved understanding of the mechanical loss has contributed significantly to the design of advanced interferometric gravitational wave detectors, which require ultra-low loss materials for their test mass mirrors.Comment: 5 pages, 3 figure but 5 figure file

    Thermal noise in half infinite mirrors with non-uniform loss: a slab of excess loss in a half infinite mirror

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    We calculate the thermal noise in half-infinite mirrors containing a layer of arbitrary thickness and depth made of excessively lossy material but with the same elastic material properties as the substrate. For the special case of a thin lossy layer on the surface of the mirror, the excess noise scales as the ratio of the coating loss to the substrate loss and as the ratio of the coating thickness to the laser beam spot size. Assuming a silica substrate with a loss function of 3x10-8 the coating loss must be less than 3x10-5 for a 6 cm spot size and a 7 micrometers thick coating to avoid increasing the spectral density of displacement noise by more than 10%. A similar number is obtained for sapphire test masses.Comment: Passed LSC (internal) review. Submitted to Phys. Rev. D. (5/2001) Replacement: Minor typo in Eq. 17 correcte

    Association of dementia with mortality among adults with down syndrome older than 35 years

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    Importance: This work quantifies the fatal burden of dementia associated with Alzheimer disease in individuals with Down syndrome (DS). Objective: To explore the association of dementia associated with Alzheimer disease with mortality and examine factors associated with dementia in adults with DS. Design, Settings and Participants: Prospective longitudinal study in a community setting in England. Data collection began March 29, 2012. Cases were censored on December 13, 2017. The potential sample consisted of all adults 36 years and older from the London Down Syndrome Consortium cohort with 2 data times and dementia status recorded (N = 300); 6 withdrew from study, 28 were lost to follow-up, and 55 had a single data collection point at time of analysis. The final sample consisted of 211 participants, with 503.92 person-years' follow-up. Exposures: Dementia status, age, sex, APOE genotype, level of intellectual disability, health variables, and living situation. Main Outcomes and Measures: Crude mortality rates, time to death, and time to dementia diagnosis with proportional hazards of predictors. Results: Of the 211 participants, 96 were women (45.5%) and 66 (31.3%) had a clinical dementia diagnosis. Twenty-seven participants (11 female; mean age at death, 56.74 years) died during the study period. Seventy percent had dementia. Crude mortality rates for individuals with dementia (1191.85 deaths per 10 000 person-years; 95% CI, 1168.49-1215.21) were 5 times higher than for those without (232.22 deaths per 10 000 person-years; 95% CI, 227.67-236.77). For those with dementia, APOE ε4 carriers had a 7-fold increased risk of death (hazard ratio [HR], 6.91; 95% CI, 1.756-27.195). For those without dementia, epilepsy with onset after age 36 years was associated with mortality (HR, 9.66; 95% CI, 1.59-58.56). APOE ε4 carriers (HR, 4.91; 95% CI, 2.53-9.56), adults with early-onset epilepsy (HR, 3.61; 95% CI, 1.12-11.60), multiple health comorbidities (HR, 1.956; 95% CI, 1.087-3.519), and those living with family (HR, 2.14; 95% CI, 1.08-4.20) received significantly earlier dementia diagnoses. Conclusions and Relevance: Dementia was associated with mortality in 70% of older adults with DS. APOE ε4 carriers and/or people with multiple comorbid health conditions were at increased risk of dementia and death, highlighting the need for good health care. For those who died without a dementia diagnosis, late-onset epilepsy was the only significant factor associated with death, raising questions about potentially undiagnosed dementia cases in this group
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