Tierra Santa, tierras perdidas, Realpolitik. La visión del Imperio Bizantino sobre Siria y Palestina a finales del siglo X y el siglo XI

This study reviews Byzantine attitudes and state policy towards the region between Antioch and Mount Sinai, stressing the general cautiousness of imperial strategy and, from the late tenth century onwards, the government’s preference for peaceful coexistence and commerce with the Fatimid caliphate. Caliph al-Ḥākim’s destruction of the church of the Holy Sepulchre in 1009 did not overturn this state of affairs, and the main bone of contention between Cairo and Constantinople was the city of Aleppo, not Jerusalem. Even here, the two powers were inclined to leave the initiative to local parties, rather than insisting on direct rule, and communications between Muslim and Byzantine-ruled territories were mostly fairly straightforward. During the relative détente of the first half of the eleventh century, pilgrimages to the Holy Land increased, and it may well have been primarily in order to impress pilgrims – those travelling from Byzantium itself, but especially those from the Christian west – that emperors lavished resources on reconstructing the church of the Holy Sepulchre in the 1030s and 1040s. Militant intervention on behalf of the Christian populations of south ern Syria and Palestine was not on their agenda. These conclusions rest on the collation of miscellaneous evidence, whose components are mostly well-known but have seldom received consideration side by side. The study highlights the value of trade to Fatimids and Byzantines alike, the esteem for ‘the holy places’ among Byzantines besides westerners, and the emperors’ desire to demonstrate concern for the Holy Sepulchre without jeopardising relations with the FatimidsEste estudio pasa revista a la política oficial del estado bizantino con respecto a la región situada entre Antioquía y el Monte Sinaí, haciendo énfasis en la prudencia adoptada por lo general en la estrategia imperial así como, a partir de finales del siglo X, en la voluntad del gobierno a favor de una coexistencia pacífica con el califato fatimí y el respeto a las relaciones comerciales. La destrucción de la iglesia del Santo Sepulcro por el califa al- Ḥākim en 1009 no alteró este estado de cosas, en el que la piedra angular de la política de contención entre el Cairo y Constantinopla estaba representada por la ciudad de Alepo, y no por Jerusalén. Incluso en esta, los dos poderes estaban inclinados a dejar la iniciativa a los partidos locales, más que en reivindicar el control directo. Las comunicaciones entre los territorios gobernados por musulmanes o bizantinos fueron así por lo general bastante regulares. Durante el parón relativo que experimentaron en la primera mitad del siglo XI, los peregrinajes a tierra santa aumentaron, y puede haber sido esencialmente para impresionar a los peregrinos (tanto los procedentes de Bizancio como, especialmente, aquellos que viajaban desde el Occidente cristiano) por lo que los emperadores invirtieron abundantes recursos en la reconstrucción de la iglesia del Santo Sepulcro entre las décadas de 1030- 1040. La intervención militar a favor de las poblaciones cristianas de Siria meridional y Palestina no estaba en su agenda. Estas conclusiones se obtienen a partir del cotejo de evidencias diversas, que eran ya bien conocidas por separado, pero que raramente habían sido contrastadas en conjunto. El estudio resalta el valor del comercio para los fatimíes y los bizantinos a la vez, la veneración por los Santos Lugares entre los bizantinos y occidentales, así como el deseo del emperador de hacer patente su preocupación por el Santo Sepulcro sin poner en riesgo sus relaciones con los fatimíes

Chatter Simulation and Detection in CNC Milling

A key feature to maintaining a safe and efficient machining operation is the avoidance of unstable vibrations of the cutting tool, commonly called chatter. This thesis explores chatter simulation and a new chatter detection algorithm developed for use in a CNC milling machine. This algorithm, based on a once per revolution sampling method, samples forces experienced during the milling process, and calculates the variance of the differences between consecutive samples. As a selected level of variance, chatter is assumed. An existing milling simulation program is modified to produce a stability lobe diagram for a given CNC machine, workpiece material, and cutting tool. Stable, unstable, and marginally stable cuts are indicated as a function of spindle speed and axial depth of cut. The chatter detection algorithm is initially verified by simulation and then added to the simulation to auto-generate stability lobe diagrams. A collection of experimental aluminum cuts is run to collect force data that can be analyzed by the detection algorithm and compared to simulation results. Experimental cut stability is determined by observation of the noise, force, and cut surface. Comparing algorithm results to observed results shows the effectiveness of the algorithm in distinguishing between stable and unstable cuts. However, further testing is needed, particularly in determining the variance threshold of the algorithm. The simulation and algorithm are also used to explore the effect of system parameters; specifically, spring constant (k) and damping ratio (ζ). This exploration shows there being a strong connection between the maximum attainable stable axial depth and the parameters

Tubular Compression Fossils from the Ediacaran Nama Group, Namibia

Abundant tubular macrofossils occur in finely laminated siltstones and shales of the 548-542 Ma Schwarzrand Subgroup. Nama Group, Namibia. The Nama tubes occur in both the Vingerbreek and Feldschuhhorn members commonly in dense populations and always in fine-grained, lower shore-face lithologies deposited below fair-weather wave base. The tubes are preserved mostly as compressed casts and molds that range in width from 0.6 to 2.1 mm: apparently incomplete specimens reach lengths up to 10 cm. All specimens show sinuous bending and occasional brittle fracture, indicating an original construction of strong but flexible organic matter. Feldschuhhorn specimens preserve fine longitudinal pleats or folds that record pliant organic walls, but the older Vingerbreek Populations do not. Similarly. some specimens in the Feldschuhhorn Member display branching. while Vingerbreek tubes do not. The abundant Feldschuhhorn tubes are assigned to the widespread Ediacaran problematicum Vendotaertia antiqua: however, the distinctive Vingerbreek population remains in open nomenclature. The most abundant fossils in Nama rocks, these tubes resemble populations in Ediacaran successions front Russia. China. Spain, and elsewhere. Beyond their local importance, then. such tubes may turn Out to be the most abundant record of Ediacaran life.Earth and Planetary SciencesOrganismic and Evolutionary Biolog

Bedform migration in a mixed sand and cohesive clay intertidal environment and implications for bed material transport predictions

Many coastal and estuarine environments are dominated by mixtures of non-cohesive sand and cohesive mud. The migration rate of bedforms, such as ripples and dunes, in these environments is important in determining bed material transport rates to inform and assess numerical models of sediment transport and geomorphology. However, these models tend to ignore parameters describing the physical and biological cohesion (resulting from clay and extracellular polymeric substances, EPS) in natural mixed sediment, largely because of a scarcity of relevant laboratory and field data. To address this gap in knowledge, data were collected on intertidal flats over a spring-neap cycle to determine the bed material transport rates of bedforms in biologically-active mixed sand-mud. Bed cohesive composition changed from below 2 vol% up to 5.4 vol% cohesive clay, as the tide progressed from spring towards neap. The amount of EPS in the bed sediment was found to vary linearly with the clay content. Using multiple linear regression, the transport rate was found to depend on the Shields stress parameter and the bed cohesive clay content. The transport rates decreased with increasing cohesive clay and EPS content, when these contents were below 2.8 vol% and 0.05 wt%, respectively. Above these limits, bedform migration and bed material transport was not detectable by the instruments in the study area. These limits are consistent with recently conducted sand-clay and sand-EPS laboratory experiments on bedform development. This work has important implications for the circumstances under which existing sand-only bedform migration transport formulae may be applied in a mixed sand-clay environment, particularly as 2.8 vol% cohesive clay is well within the commonly adopted definition of “clean sand”

Change and Exchange: Economies of Literature and Knowledge in Early Modern Europe

The introductory essay outlines the way in which Change and Exchange places literature, and, in a wider sense, imaginative practice, at the centre of early modern economic knowledge. Probing the affinity between economic and metaphorical experience in terms of the transactional processes of change and exchange, it sets up the parameters within which the essays in the volume collectively forge a language to grasp early modern economic phenomena and their epistemic dimensions. It prepares the reader for the stimulating combination of materials that the book presents: the range of generic contexts engendered by emergent economic practices, structures of feeling and modes of knowing made available by new economic relations, and economies of transformation in discursive domains that are distinct from ‘economics’ as we understand it but cognate in their intuition of change and exchange as shaping agents

Hepatitis B and liver cancer knowledge and practices among healthcare and public health professionals in China: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>Chronic hepatitis B virus (HBV) infection is the leading cause of liver disease and liver cancer and a major source of health-related discrimination in China. To better target HBV detection and prevention programs, it is necessary to assess existing HBV knowledge, educational resources, reporting, and preventive practices, particularly among those health professionals who would be responsible for implementing such programs.</p> <p>Methods</p> <p>At the China National Conference on the Prevention and Control of Viral Hepatitis on April 26-29, 2004, the Asian Liver Center at Stanford University partnered with the China Foundation for Hepatitis Prevention and Control to distribute a voluntary written questionnaire to Chinese healthcare and public health professionals from regional and provincial Chinese Centers for Disease Control and Prevention, health departments, and medical centers. Correct responses to survey questions were summed into a total knowledge score, and multivariate linear regression was used to compare differences in the score by participant characteristics.</p> <p>Results</p> <p>Although the median score was 81% correct, knowledge about HBV was inadequate, even among such highly trained health professionals. Of the 250 participants who completed the survey, 34% did not know that chronic HBV infection is often asymptomatic and 29% did not know that chronic HBV infection confers a high risk of cirrhosis, liver cancer, and premature death. Furthermore, 34% failed to recognize all the modes of HBV transmission and 30% did not know the importance of the hepatitis B vaccine in preventing liver disease. Respondents who reported poorer preventive practices, such as not having personally been tested for HBV and not routinely disposing of used medical needles, scored significantly lower in HBV knowledge than those who reported sound preventive practices. Of note, 38% of respondents reported positive HBsAg results to patients' employers and 25% reported positive results to patients' schools, thereby subjecting those with positive results to potential discriminatory practices.</p> <p>Conclusions</p> <p>These results indicate that there is a need for development of effective educational programs to improve HBV knowledge among health professionals and the general public to avoid missed vaccination opportunities, reduce misconceptions, and eliminate discrimination based on chronic hepatitis B in China.</p

Validity and reliability of metrics for translation of regional anaesthesia performance from cadavers to patients

Background: Our goal is to develop metrics that quantify the translation of performance from cadavers to patients. Our primary objective was to develop steps and error checklists from a Delphi questionnaire. Our second objective was to show that our test scores were valid and reliable.Methods: Sixteen UK experts identified 15 steps conducive to good performance and 15 errors to be avoided during interscalene block on the soft-embalmed cadaver and patients. Thereafter, six experts and six novices were trained, and then tested. Training consisted of psychometric assessment, an anatomy tutorial, volunteer scanning, and ultrasound-guided needle insertion on a pork phantom and on a soft-embalmed cadaver. For testing, participants conducted a single interscalene block on a dedicated soft-embalmed cadaver whilst wearing eye tracking glasses.Results: We developed a 15-step checklist and a 15-error checklist. The internal consistency of our steps measures were 0.83 (95% confidence interval [CI]: 0.78-0.89) and 0.90 (95% CI: 0.87-0.93) for our error measures. The experts completed more steps (mean difference: 3.2 [95% CI: 1.5-4.8]; P&lt;0.001), had less errors (mean difference: 4.9 [95% CI: 3.5-6.3]; P&lt;0.001), had better global rating scores (mean difference: 6.8 [95% CI: 3.6-10.0]; P&lt;0.001), and more eye-gaze fixations (median of differences: 128 [95% CI: 0-288]; P=0.048). Fixation count correlated negatively with steps (r=-0.60; P=0.04) and with errors (r=0.64; P=0.03).Conclusions: Our tests to quantify ultrasound-guided interscalene nerve block training and performance were valid and reliable.</p

A Digital Health Behavior Intervention to Prevent Childhood Obesity

Infant growth predicts long-term obesity and cardiovascular disease. Previous interventions designed to prevent obesity in the first 2 years of life have been largely unsuccessful. Obesity prevalence is high among traditional racial and ethnic minority groups. To compare the effectiveness of adding a digital childhood obesity prevention intervention to health behavior counseling delivered by pediatric primary care clinicians. Individually randomized, parallel-group trial conducted at 6 US medical centers and enrolling patients shortly after birth. To be eligible, parents spoke English or Spanish, and children were born after 34 weeks’ gestational age. Study enrollment occurred between October 2019 and January 2022, with follow-up through January 2024. In the clinic-based health behavior counseling (clinic-only) group, pediatric clinicians used health literacy–informed booklets at well-child visits to promote healthy behaviors (n = 451). In the clinic + digital intervention group, families also received health literacy–informed, individually tailored, responsive text messages to support health behavior goals and a web-based dashboard (n = 449). The primary outcome was child weight-for-length trajectory over 24 months. Secondary outcomes included weight-for-length z score, body mass index (BMI) z score, and the percentage of children with overweight or obesity. Of 900 randomized children, 86.3% had primary outcome data at the 24-month follow-up time point; 143 (15.9%) were Black, non-Hispanic; 405 (45.0%) were Hispanic; 185 (20.6%) were White, non-Hispanic; and 165 (18.3%) identified as other or multiple races and ethnicities. Children in the clinic + digital intervention group had a lower mean weight-for-length trajectory, with an estimated reduction of 0.33 kg/m (95% CI, 0.09 to 0.57) at 24 months. There was also an adjusted mean difference of −0.19 (95% CI, −0.37 to −0.02) for weight-for-length z score and −0.19 (95% CI, −0.36 to −0.01) for BMI z score. At age 24 months, 23.2% of the clinic + digital intervention group compared with 24.5% of the clinic-only group had overweight or obesity (adjusted risk ratio, 0.91 [95% CI, 0.70 to 1.17]) based on the Centers for Disease Control and Prevention criteria of BMI 85th percentile or greater. At that age, 7.4% of the clinic + digital intervention group compared with 12.7% of the clinic-only group had obesity (adjusted risk ratio, 0.56 [95% CI, 0.36 to 0.88]). A health literacy–informed digital intervention improved child weight-for-length trajectory across the first 24 months of life and reduced childhood obesity at 24 months. The intervention was effective in a racially and ethnically diverse population that included groups at elevated risk for childhood obesity. ClinicalTrials.gov Identifier: NCT0404246