World-Wide Web scaling exponent from Simon's 1955 model

Recently, statistical properties of the World-Wide Web have attracted considerable attention when self-similar regimes have been observed in the scaling of its link structure. Here we recall a classical model for general scaling phenomena and argue that it offers an explanation for the World-Wide Web's scaling exponent when combined with a recent measurement of internet growth.Comment: 1 page RevTeX, no figure

Percutaneous hepatic melphalan perfusion: single center experience of procedural characteristics, hemodynamic response, complications, and postoperative recovery

BACKGROUND: Percutaneous hepatic melphalan perfusion (PHMP) for the selective treatment of hepatic metastases is known to be associated with procedural hypotension and coagulation disorders. Studies on anesthetic management, perioperative course, complications, and postoperative recovery in the intensive care unit (ICU) have not been published. METHODS: In a retrospective observational study, we analyzed consecutive patients who were admitted for PHMP over a 6-year period (2016–2021). Analyses included demographic, treatment, and outcome data with regard to short-term complications until ICU discharge. RESULTS: Fifty-three PHMP procedures of 16 patients were analyzed. In all of the cases, procedure-related hypotension required the median (range) highest noradrenaline infusion rate of 0.5 (0.17–2.1) μg kg min(-1) and fluid resuscitation volume of 5 (3–14) liters. Eighty-four PHMP-related complications were observed in 33 cases (62%), of which 9 cases (27%) involved grade III and IV complications. Complications included airway constriction (requiring difficult airway management), vascular catheterization issues (which resulted in the premature termination of PHMP, as well as to the postponement of PHMP and to the performance of endovascular bleeding control after PHMP), and renal failure that required hemodialysis. Discharge from the ICU was possible after one day in most cases (n = 45; 85%); however, in 12 cases (23%), prolonged mechanical ventilation was required. There were no procedure-related fatalities. CONCLUSIONS: PHMP is frequently associated with challenging cardiovascular conditions and complications that require profound anesthetic skills. For safety reasons, PHMP should only be performed in specialized centers that provide high-level hospital infrastructures and interdisciplinary expertise

The global naturalized Alien Flora (GloNAF) database

This dataset provides the Global Naturalized Alien Flora (GloNAF) database, ver-sion 1.2. Glo NAF represents a data compendium on th e occurrence and identit y of naturalizedalien vascular plant taxa across geographic regions (e.g. countries, states, provinces, districts,islands) around the globe. The dataset includes 13,939 taxa and covers 1,029 regions (including381 islands). The dataset is based on 210 data sources. For each ta x on-b y-region combination, wepr ovide information on whether the tax on is consider ed to be naturalized in the specific region(i.e. has established self-sustaining popula tions in the wild). Non-native taxa are marked as“alien”, when it is not clear whether they are naturalized. To facilitate alignment with other plantdatabases, we pro v ide f or each taxon the name as given in the original data source and the stan-dardized taxon and family names used by The Plant List Version 1.1 (http://www.theplantlist.org/). We pro vide an ESRI shapefile including polygons f or each region and informa tion on whetherit is an island or a mainland region, the country and the Taxonomic Databases Working Group(TDWG) regions it is part of (TDWG levels 1–4). We also provide several variables that can beused to filter the data according to quality and completeness of alien taxon lists, which varyamong the combinations of regions and da ta sources. A pre vious version of the GloNAF dataset(version 1.1) has already been used in several studies on, for example, historical spatial flows oftaxa between continents and geographical patterns and determinants of naturalization across dif-ferent taxonomic groups. We intend the updated and expanded GloNAF version presented hereto be a global resource useful for studying plant inv asions and changes in biodiversity from regio-nal to global scales. We release these data into the public domain under a Crea ti ve CommonsZer o license waiver (https://creati v ecommons.org/share-y our -work/public-domain/cc0/). Wheny ou use the da ta in your publication, we request that y ou cite this da ta paper. If GloN AF is amajor part of the data analyzed in your study, you should consider inviting the GloNAF coreteam (see Metadata S1: Originators in the Overall project description) as collaborators. If youplan to use the GloNAF dataset, we encourage y ou to contact the GloNAF core team to checkwhether there have been recent updates of the dataset, and whether similar analyses are already ongoing

A Multilaboratory Comparison of Calibration Accuracy and the Performance of External References in Analytical Ultracentrifugation

Analytical ultracentrifugation (AUC) is a first principles based method to determine absolute sedimentation coefficients and buoyant molar masses of macromolecules and their complexes, reporting on their size and shape in free solution. The purpose of this multi-laboratory study was to establish the precision and accuracy of basic data dimensions in AUC and validate previously proposed calibration techniques. Three kits of AUC cell assemblies containing radial and temperature calibration tools and a bovine serum albumin (BSA) reference sample were shared among 67 laboratories, generating 129 comprehensive data sets. These allowed for an assessment of many parameters of instrument performance, including accuracy of the reported scan time after the start of centrifugation, the accuracy of the temperature calibration, and the accuracy of the radial magnification. The range of sedimentation coefficients obtained for BSA monomer in different instruments and using different optical systems was from 3.655 S to 4.949 S, with a mean and standard deviation of (4.304 ± 0.188) S (4.4%). After the combined application of correction factors derived from the external calibration references for elapsed time, scan velocity, temperature, and radial magnification, the range of s-values was reduced 7-fold with a mean of 4.325 S and a 6-fold reduced standard deviation of ± 0.030 S (0.7%). In addition, the large data set provided an opportunity to determine the instrument-to-instrument variation of the absolute radial positions reported in the scan files, the precision of photometric or refractometric signal magnitudes, and the precision of the calculated apparent molar mass of BSA monomer and the fraction of BSA dimers. These results highlight the necessity and effectiveness of independent calibration of basic AUC data dimensions for reliable quantitative studies

A multilaboratory comparison of calibration accuracy and the performance of external references in analytical ultracentrifugation.

Analytical ultracentrifugation (AUC) is a first principles based method to determine absolute sedimentation coefficients and buoyant molar masses of macromolecules and their complexes, reporting on their size and shape in free solution. The purpose of this multi-laboratory study was to establish the precision and accuracy of basic data dimensions in AUC and validate previously proposed calibration techniques. Three kits of AUC cell assemblies containing radial and temperature calibration tools and a bovine serum albumin (BSA) reference sample were shared among 67 laboratories, generating 129 comprehensive data sets. These allowed for an assessment of many parameters of instrument performance, including accuracy of the reported scan time after the start of centrifugation, the accuracy of the temperature calibration, and the accuracy of the radial magnification. The range of sedimentation coefficients obtained for BSA monomer in different instruments and using different optical systems was from 3.655 S to 4.949 S, with a mean and standard deviation of (4.304 ± 0.188) S (4.4%). After the combined application of correction factors derived from the external calibration references for elapsed time, scan velocity, temperature, and radial magnification, the range of s-values was reduced 7-fold with a mean of 4.325 S and a 6-fold reduced standard deviation of ± 0.030 S (0.7%). In addition, the large data set provided an opportunity to determine the instrument-to-instrument variation of the absolute radial positions reported in the scan files, the precision of photometric or refractometric signal magnitudes, and the precision of the calculated apparent molar mass of BSA monomer and the fraction of BSA dimers. These results highlight the necessity and effectiveness of independent calibration of basic AUC data dimensions for reliable quantitative studies

Optimization of soot deposition by high-temperature prepolarization of a resistive particulate matter sensor

For the purposes of the onboard diagnosis (OBD) of diesel particulate filters (DPFs) in diesel exhaust treatment systems, a particulate matter (PM) sensor is applied downstream from the DPFs to detect small amounts of diesel soot that passed through the filter. The state-of-the-art technology is a sensor based on the resistive measurement principle, i.e., charged soot particles are attracted by electrophoretic forces, deposited on an interdigital electrode (IDE) structure and conductive soot bridges that reduce the overall resistance are formed. This paper reports how the response time of a resistively working particulate matter sensor can be shortened up to 30 % by the optimization of soot deposition that is initiated by a change in the sensor operation strategy. The measurement voltage is applied for prepolarization during the sensor regeneration phase rather than during the cooling phase before the measurement is commonly done. Experiments were performed at diesel engine test benches to examine this context and simulations of the electric field above and below the IDE structure. The data are used to deduct a model, including the solid state chemistry of the sensor's ceramic materials, the effect of impurities on the electric field properties and the interconnection with the soot deposition, which defines the sensor's response

Influence of the interleukin-converting enzyme inhibitor HMR-3480 on myocardial stunning in pigs in vivo

BACKGROUND: The proinflammatory cytokine interleukin-1 beta is converted into its active form by interleukin-1 beta-converting enzyme (ICE). Circulating cytokines may promote myocardial dysfunction (stunning) after ischemia. OBJECTIVE: To investigate whether ICE inhibition by HMR-3840 improves myocardial stunning in vivo. METHODS: Anesthetized (isoflurane and fentanyl) pigs were used for measurement of left ventricular (LV) pressure, cardiac output and blood flow in the left anterior descending coronary artery (LAD) and left circumflex coronary artery. Regional myocardial function was assessed by sonomicrometry as systolic wall thickening and mean systolic thickening velocity in the anteroapical and posterobasal walls. The animals were subjected to 10 min of LAD occlusion followed by 4 h of reperfusion. The ICE inhibitor (flow-adjusted to achieve coronary plasma concentrations of 10 mug/mL) (ISCH, n=7) or the vehicle (CON, n=7) was infused via a side branch into the LAD during ischemia, or during ischemia and the first 60 min of reperfusion (REP, n=6). RESULTS: Occlusion of the LAD resulted in systolic outward movement (bulging) of the anteroapical wall during ischemia in all groups. Infusion of the ICE inhibitor had no effect on functional recovery when given during ischemia or when given during reperfusion (at the end of reperfusion in the anteroapical wall, values for systolic wall thickening were: CON 17.3+/-7.3%, ISCH 23.2+/-9.8% and REP 19.3+/-6.1%; and values for mean systolic thickening velocity were: CON 4.3+/-1.1 mm/s, ISCH 6.1+/-3.9 mm/s and REP 5.2+/-1.7 mm/s; all P values not significant for CON versus ISCH or REP). LAD blood flow was not affected by HMR-3840 (23.4+/-5.2 mL/min versus 24.3+/-8.1 mL/min; P not significant). Global myocardial function (LV pressure, maximum rate of LV pressure increase and cardiac output) was not different between controls and treatment groups during reperfusion. CONCLUSION: ICE inhibition by HMR-3480 had no effect on myocardial stunning in pigs in viv