A Comparison of Wood Density between Classical Cremonese and Modern Violins

Classical violins created by Cremonese masters, such as Antonio Stradivari and Giuseppe Guarneri Del Gesu, have become the benchmark to which the sound of all violins are compared in terms of their abilities of expressiveness and projection. By general consensus, no luthier since that time has been able to replicate the sound quality of these classical instruments. The vibration and sound radiation characteristics of a violin are determined by an instrument's geometry and the material properties of the wood. New test methods allow the non-destructive examination of one of the key material properties, the wood density, at the growth ring level of detail. The densities of five classical and eight modern violins were compared, using computed tomography and specially developed image-processing software. No significant differences were found between the median densities of the modern and the antique violins, however the density difference between wood grains of early and late growth was significantly smaller in the classical Cremonese violins compared with modern violins, in both the top (Spruce) and back (Maple) plates (p = 0.028 and 0.008, respectively). The mean density differential (SE) of the top plates of the modern and classical violins was 274 (26.6) and 183 (11.7) gram/liter. For the back plates, the values were 128 (2.6) and 115 (2.0) gram/liter. These differences in density differentials may reflect similar changes in stiffness distributions, which could directly impact vibrational efficacy or indirectly modify sound radiation via altered damping characteristics. Either of these mechanisms may help explain the acoustical differences between the classical and modern violins

Screening of suitable cationic dopants for solar absorber material CZTS/Se: A first principles study

The earth abundant and non-toxic solar absorber material kesterite Cu2ZnSn(S/Se)(4) has been studied to achieve high power conversion efficiency beyond various limitations, such as secondary phases, antisite defects, band gap adjustment and microstructure. To alleviate these hurdles, we employed screening based approach to find suitable cationic dopant that can promote the current density and the theoretical maximum upper limit of the energy conversion efficiency (P(%)) of CZTS/Se solar devices. For this task, the hybrid functional (Heyd, Scuseria and Ernzerhof, HSE06) were used to study the electronic and optical properties of cation (Al, Sb, Ga, Ba) doped CZTS/Se. Our in-depth investigation reveals that the Sb atom is suitable dopant of CZTS/CZTSe and also it has comparable bulk modulus as of pure material. The optical absorption coefficient of Sb doped CZTS/Se is considerably larger than the pure materials because of easy formation of visible range exciton due to the presence of defect state below the Fermi level, which leads to an increase in the current density and P(%). Our results demonstrate that the lower formation energy, preferable energy gap and excellent optical absorption of the Sb doped CZTS/Se make it potential component for relatively high efficient solar cells

Improving the use of research evidence in guideline development: 15. Disseminating and implementing guidelines

BACKGROUND: The World Health Organization (WHO), like many other organisations around the world, has recognised the need to use more rigorous processes to ensure that health care recommendations are informed by the best available research evidence. This is the 15(th )of a series of 16 reviews that have been prepared as background for advice from the WHO Advisory Committee on Health Research to WHO on how to achieve this. OBJECTIVES: In this review we address strategies for the implementation of recommendations in health care. METHODS: We examined overviews of systematic reviews of interventions to improve health care delivery and health care systems prepared by the Cochrane Effective Practice and Organisation of Care (EPOC) group. We also conducted searches using PubMed and three databases of methodological studies for existing systematic reviews and relevant methodological research. We did not conduct systematic reviews ourselves. Our conclusions are based on the available evidence, consideration of what WHO and other organisations are doing and logical arguments. KEY QUESTIONS AND ANSWERS: What should WHO do to disseminate and facilitate the uptake of recommendations? • WHO should choose strategies to implement their guidelines from among those which have been evaluated positively in the published literature on implementation research • Because the evidence base is weak and modest to moderate effects, at best, can be anticipated, WHO should promote rigorous evaluations of implementation strategies. What should be done at headquarters, by regional offices and in countries? • Adaptation and implementation of WHO guidelines should be done locally, at the national or sub-national level. • WHO headquarters and regional offices should support the development and evaluation of implementation strategies by local authorities

Mortality after admission for acute myocardial infarction in Aboriginal and non-Aboriginal people in New South Wales, Australia: a multilevel data linkage study

Background - Heart disease is a leading cause of the gap in burden of disease between Aboriginal and non-Aboriginal Australians. Our study investigated short- and long-term mortality after admission for Aboriginal and non-Aboriginal people admitted with acute myocardial infarction (AMI) to public hospitals in New South Wales, Australia, and examined the impact of the hospital of admission on outcomes. Methods - Admission records were linked to mortality records for 60047 patients aged 25–84 years admitted with a diagnosis of AMI between July 2001 and December 2008. Multilevel logistic regression was used to estimate adjusted odds ratios (AOR) for 30- and 365-day all-cause mortality. Results - Aboriginal patients admitted with an AMI were younger than non-Aboriginal patients, and more likely to be admitted to lower volume, remote hospitals without on-site angiography. Adjusting for age, sex, year and hospital, Aboriginal patients had a similar 30-day mortality risk to non-Aboriginal patients (AOR: 1.07; 95% CI 0.83-1.37) but a higher risk of dying within 365 days (AOR: 1.34; 95% CI 1.10-1.63). The latter difference did not persist after adjustment for comorbid conditions (AOR: 1.12; 95% CI 0.91-1.38). Patients admitted to more remote hospitals, those with lower patient volume and those without on-site angiography had increased risk of short and long-term mortality regardless of Aboriginal status. Conclusions - Improving access to larger hospitals and those with specialist cardiac facilities could improve outcomes following AMI for all patients. However, major efforts to boost primary and secondary prevention of AMI are required to reduce the mortality gap between Aboriginal and non-Aboriginal people

Best Practices in Researching Service-Learning at Community Colleges

In recent years, an increasing number of community colleges have integrated some form of service-learning into their programs or courses with the idea that it will promote civic engagement, increase student satisfaction with their courses and college experience as a whole, and improve learning outcomes. There is a good amount of research published on service-learning programs and outcomes conducted at four-year institutions, though there is a dearth of studies available on service-learning at community colleges. Because community colleges serve a purpose unique from that of four-year colleges and universities, both in their mission and often in the students they serve, research on service-learning at community colleges should also be distinct from investigations at the four-year level

Association between Ambient Noise Exposure and School Performance of Children Living in An Urban Area: A Cross-Sectional Population-Based Study

16 pages Article disponible à l'adresse suivante : http://link.springer.com/article/10.1007%2Fs11524-013-9843-6International audienceMost of the studies investigating the effects of the external noise on children's school performance have concerned pupils in schools exposed to high levels due to aircraft or freeway traffic noise. However, little is known about the consequences of the chronic ambient noise exposure at a level commonly encountered in residential urban areas. This study aimed to assess the relationship between the school performance of 8- to 9-year-old-children living in an urban environment and their chronic ambient noise exposure at home and at school. The children's school performances on the national standardized assessment test in French and mathematics were compared with the environmental noise levels. Children's exposure to ambient noise was calculated in front of their bedrooms (Lden) and schools (LAeq,day) using noise prediction modeling. Questionnaires were distributed to the families to collect potential confounding factors. Among the 746 respondent children, 586 were included in multilevel analyses. On average, the LAeq,day at school was 51.5 dB (SD= 4.5 dB; range = 38-58 dB) and the outdoor Lden at home was 56.4 dB (SD= 4.4 dB; range = 44-69 dB). LAeq,day at school was associated with impaired mathematics score (p = 0.02) or impaired French score (p = 0.01). For a + 10 dB gap, the French and mathematics scores were on average lower by about 5.5 points. Lden at home was significantly associated with impaired French performance when considered alone (p < 10(-3)) and was borderline significant when the combined home-school exposure was considered (p = 0.06). The magnitude of the observed effect on school performance may appear modest, but should be considered in light of the number of people who are potentially chronically exposed to similar environmental noise levels

Radiofrequency cardiac ablation with catheters placed on opposing sides of the ventricular wall: Computer modelling comparing bipolar and unipolar modes

Purpose: The aim of this study was to compare the efficacy of bipolar (BM) vs. unipolar (UM) mode of radiofrequency ablation (RFA) in terms of creating transmural lesions across the interventricular septum (IVS) and ventricular free wall (VFW). Materials and methods: We built computational models to study the temperature distributions and lesion dimensions created by BM and UM on IVS and VFW during RFA. Two different UM types were considered: sequential (SeUM) and simultaneous (SiUM). The effect of ventricular wall thickness, catheter misalignment, epicardial fat, and presence of air in the epicardial space were also studied. Results: Regarding IVS ablation, BM created transmural and symmetrical lesions for wall thicknesses up to 15 mm. SeUM and SiUM were not able to create transmural lesions with IVS thicknesses >= 12.5 and 15 mm, respectively. Lesions were asymmetrical only with SeUM. For VFW ablation, BM also created transmural lesions for wall thicknesses up to 15 mm. However, with SeUM and SiUM transmurality was obtained for VFW thicknesses <= 7.5 and 12.5 mm, respectively. With the three modes, VFW lesions were always asymmetrical. In the scenario with air or a fat tissue layer on the epicardial side, only SiUM was capable of creating transmural lesions. Overall, BM was superior to UM in IVS and VFW ablation when the catheters were not aligned. Conclusions: Our findings suggest that BM is more effective than UM in achieving transmurality across both ventricular sites, except in the situation of the epicardial catheter tip surrounded by air or placed over a fat tissue layer.This work received financial support from the Spanish 'Plan Nacional de I+D+I del Ministerio de Ciencia e Innovacion' (TEC2011-27133-C02-01), and from the Universitat Politecnica de Valencia (PAID-06-11 Ref. 1988). A. Gonzalez-Suarez is the recipient of a Grant VaLi+D (ACIF/2011/194) from the Generalitat Valenciana, Spain. The authors alone are responsible for the content and writing of the paper.González Suárez, A.; Trujillo Guillen, M.; Koruth, J.; D'avila, A.; Berjano, E. (2014). Radiofrequency cardiac ablation with catheters placed on opposing sides of the ventricular wall: Computer modelling comparing bipolar and unipolar modes. International Journal of Hyperthermia. 30(6):372-384. https://doi.org/10.3109/02656736.2014.949878S372384306SIVAGANGABALAN, G., BARRY, M. A., HUANG, K., LU, J., POULIOPOULOS, J., THOMAS, S. P., … KOVOOR, P. (2010). Bipolar Ablation of the Interventricular Septum is More Efficient at Creating a Transmural Line than Sequential Unipolar Ablation. Pacing and Clinical Electrophysiology, 33(1), 16-26. doi:10.1111/j.1540-8159.2009.02602.xNagashima, K., Watanabe, I., Okumura, Y., Ohkubo, K., Kofune, M., Ohya, T., … Hirayama, A. (2011). Lesion Formation by Ventricular Septal Ablation With Irrigated Electrodes. 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Plant use of the Maasai of Sekenani Valley, Maasai Mara, Kenya

Traditional plant use is of tremendous importance in many societies, including most rural African communities. This knowledge is however, rapidly dwindling due to changes towards a more Western lifestyle, and the influence of modern tourism. In case of the Sekenani Maasai, the recent change from a nomadic to a more sedentary lifestyle has not, thus far lead to a dramatic loss of traditional plant knowledge, when compared to other Maasai communities. However, in Sekenani, plants are used much less frequently for manufacturing tools, and for veterinary purposes, than in more remote areas. While the knowledge is still present, overgrazing and over-exploitation of plant resources have already led to a decline of the plant material available. This paper examines the plant use of the Maasai in the Sekenani Valley, North of the Masaai Mara National Reserve. The Maasai pastoralists of Kenya and Tanzania use a large part of the plants in their environment for many uses in daily life. The plant use and knowledge of the Sekenani Maasai is of particular interest, as their clan, the "Il-Purko", was moved from Central Kenya to this region by the British Colonial Administration in 1904. The results of this study indicate that despite their relocation 100 years ago, the local population has an extensive knowledge of the plants in their surroundings, and they ascribe uses to a large percentage of the plants found. One-hundred-fifty-five plant species were collected, identified and their Maa names and traditional uses recorded. Although fifty-one species were reported as of "no use", only eighteen of these had no Maasai name. Thirty-three were recognized by a distinctive Maa name. Thirty-nine species had a medicinal use, and 30 species served as fodder for livestock. Six species could not be identified. Of these plants five were addressed by the Maasai with distinct names. This exemplifies the Sekenani Maasai's in-depth knowledge of the plant resources. Traditionally, the Maasai attribute most illnesses to the effect of pollutants that block or inhibit digestion. These pollutants can include "polluted" food, contact with sick people and witchcraft. In most cases the treatment of illness involves herbal purgatives to cleanse the patient. There are alsofrequent indications of plant use for common problems like wounds, parasites, body aches and burns

The clinical presentation of preterm cerebellar haemorrhage

The objective of this study was to evaluate clinical symptoms and findings on cranial ultrasound (CUS) in preterm infants with cerebellar haemorrhage through retrospective analysis of all preterm infants with a postnatal CUS or MRI diagnosis of cerebellar haemorrhage admitted in a tertiary care centre between January 2002 and June 2009. Fifteen infants were identified; median gestational age was 25 2/7 weeks and median birth weight 730 g. We discerned six types of haemorrhage: subarachnoid (n=3), folial (n=1), lobar (n=9, of which 4 bilateral), giant lobar (n=1, including vermis) and contusional (n=1). Especially in infants with lobar cerebellar haemorrhage, CUS showed preceding or concurrent lateral ventricle dilatation, mostly without intraventricular haemorrhage (IVH). Thirteen infants suffered from notable, otherwise unexplained motor agitation in the days preceding the diagnosis. In conclusion, motor agitation may be a presenting symptom of cerebellar haemorrhage in preterm infants. Unexplained ventriculomegaly can be a first sign of cerebellar haemorrhage and should instigate sonographic exploration of the cerebellum