Multiple Grading Research Articles

Review of small-bowel cleansing scales in capsule endoscopy: A panoply of choices.

Evaluation of the quality of small-bowel cleansing is required to assess the reliability of findings in capsule endoscopy (CE). Moreover, consensus regarding the need of intestinal preparation for CE remains to be achieved. The presence of multiple grading scales for small-bowel preparation in CE, which are time-consuming and complicated, adds difficulty to the comparison of different small-bowel cleansing regimens and their application in clinical practice. Nowadays, a validated scale universally accepted for grading small-bowel cleansing is lacking. In fact, there are numerous grading systems with very different technical characteristics, namely, the parameters and the portion of the CE video that are analyzed, the objectivity of the analysis, the lesser or greater dependency on the operator, and the validation of the score. The authors performed a review which aims to systematize and summarize currently available small-bowel grading scales in CE.

High-Efficiency and Crack-Free InGaN-Based LEDs on a 6-inch Si (111) Substrate With a Composite Buffer Layer Structure and Quaternary Superlattices Electron-Blocking Layers

In this paper, a composite buffer layer structure (CBLS) with multiple AlGaN layers and grading of Al composition/u-GaN1/(AlN/GaN) superlattices/u-GaN2 and InAlGaN/AlGaN quaternary superlattices electron-blocking layers (QSLs-EBLs) are introduced into the epitaxial growth of InGaN-based light-emitting diodes (LEDs) on 6-inch Si (111) substrates to suppress cracking and improve the crystalline quality and emission efficiency. The effect of CBLS and QSLs-EBL on the crystalline quality and emission efficiency of InGaN-based LEDs on Si substrates was studied in detail. Optical microscopic images revealed the absence of cracks and Ga melt-back etching. The atomic force microscopy images exhibited that the root-mean-square value of the surface morphology was only 0.82 nm. The full widths at half maxima of the (0002) and (1012) reflections in the double crystal X-ray rocking curve were ~330 and 450 respectively. The total threading dislocation density, revealed by transmission electron microscopy, was <; 6× 108 cm-2. From the material characterizations, described above, blue and white LEDs emitters were fabricated using the epiwafers of InGaN-based LEDs on 6-inch Si substrates. The blue LEDs emitter that comprised blue LEDs chip and clear lenses had an emission power of 490 mW at 350 mA, a wall-plug efficiency of 45% at 350 mA, and an efficiency droop of 80%. The white LEDs emitter that comprised blue LEDs chip and yellow phosphor had an emission efficiency of ~110 lm/W at 350 mA and an efficiency droop of 78%. These results imply that the use of a CBLS and QSLs-EBL was found to be very simple and effective in fabricating high-efficiency InGaN-based LEDs on Si for solid-state lighting applications.

Response to Letter to the Editor by Dr. Tamas Karosi Re

To the Editor: We appreciate Dr. Tamas Karosi’s letter and would like to address some of his concerns and comments. We acknowledge the recent manuscript by Karosi et. al (1), in which high resolution computed tomography (HRCT) findings were compared to histopathology of stapedectomy specimens (i.e. stapes footplates). The current study differs because the entire otic capsule was able to be evaluated in these post-mortem temporal bone specimens. Evaluation of the otic capsule is important because otosclerotic foci may be missed with evaluation of the surgically removed footplate only. Additionally, evaluation of the entire temporal bone specimen allows identification of peri-cochlear or retrofenestral otosclerosis, which is clinically important as peri-cochlear foci may cause sensorineural hearing loss. We agree that HRCT may be used in the diagnostic evaluation of otosclerosis, including evaluation of differential diagnoses, and planning or counseling prior to surgical treatment. Although there is no standard medical treatment for otosclerosis, some practitioners may employ fluoride (2) or bisphosphonates in cases of progressive sensorineural hearing loss due to otosclerosis (3, 4, 5). In this instance, HRCT may be employed to confirm retrofenestral otosclerosis before considering medical treatment. During this study, there were multiple examples of histologically inactive foci that could be seen on HRCT, as depicted in Figure 1. of the manuscript. Thus, it is not clear that the diagnostic value of HRCT is significantly reduced in cases with inactive otosclerotic foci. We disagree that post mortem histopathologic findings are of limited value in clinical practice. Since the complete otic capsule cannot be examined histopathologically during life, post mortem evaluation provides important information about otosclerosis and other diseases of the temporal bone. These findings can be translated into clinical practice (6). The temporal bone specimens in this study underwent HRCT scanning prior to decalcification with ethylenediamine tetracetic acid (EDTA) and embedding in celloidin, and thus do not affect the HRCT findings. Fixation in formalin with 1% acetic acid and embedding in celloidin results in the best morphology of the temporal bone (7). Autolysis is minimized by rapid fixation of the tissues after death, and is not caused by EDTA or related to the age of archived temporal bone specimens. The goal of this study was to compare HRCT findings to pathology directly, rather than to audiologic data. Areas of both active and inactive otosclerosis may co-exist in the same specimen (8), thus complicating the categorization of these specimens. In the future, it would be worthwhile to specifically compare histologic activity to HRCT imaging characteristics for each focus of otosclerosis, as the availability of pathology and HRCT for the same specimen will finally enable this direct comparison. There are multiple HRCT grading systems available (1, 9, 10, 11, 12), each valuable and designed with different purposes, with no single widely accepted system. We used a simplified approach with three zones. For this study, it was important to characterize findings anterior to the oval window, around the cochlea, and in the round window niche separately; we did not see the need for additional subdivisions with these three zones, especially given the small sample size. We do not believe that the finding of 80% overall sensitivity of HRCT for the diagnosis of otosclerosis in this study is “so small that it excludes further clinical applications in the future.” Inclusion of all available specimens (including one histologic otosclerosis specimen as noted in the discussion) and comparison to temporal bone pathology may account for the reduced sensitivity as compared to other studies comparing CT to audiologic, clinical, and stapes footplate only specimens. Additionally the small sample size in this study should be considered when interpreting these results.

Broodstock contribution after mass spawning and size grading in barramundi (Lates calcarifer, Bloch)

Appropriately designed selective breeding programs are needed to limit the loss of genetic diversity and control levels of inbreeding, and to base selection decisions on data collected from many offspring of many families. Achieving a relatively even contribution by broodstock to subsequent generations is necessary and for many aquaculture species this is possible to control through mate pairing. Barramundi (Lates calcarifer) provides an exception, because it is a species that mass spawn in small groups and whose offspring are repeatedly size graded in an effort to avoid cannibalism. Following mass spawning a large broodstock group of 33 barramundi, levels of parental contribution and multiple measures of genetic diversity were estimated over the course of repeated size grading events. Parentage was inferred using 17 microsatellite DNA loci. Twelve dams and twenty-one sires were artificially spawned over two nights and sampled at 1, 18 and 90days post hatch (dph). Broodstock contributions were skewed and the contribution by individual dams and sires was as high as 48 and 16% respectively at 1dph. Despite the unequal contribution and high variance in family sizes, 31 broodstock were detected as contributing to the spawning events and as a result up to 103 full-sibling families were detected (18dph, n=472). A reduction in allelic richness (Ar) was identified from broodstock to offspring at 1dph, (Ar was 3.94 among broodstock and 3.52 among offspring sampled). However, no further loss of Ar or genetic diversity was detected in the offspring from 1 to 90dph, which included the period of metamorphosis, multiple size grading events and losses through size culling, mortalities and the sale of juveniles. The effective census population size ratio (Ne/Nc) ranged from 0.31 to 0.51 at times of sampling, (Ne was calculated between 10.1 and 16.7, well below the broodstock census size of 33) and the rate of inbreeding was less than 5%. This research provides valuable baseline data that can be used to make recommendations for the maintenance of genetic diversity and control of inbreeding for a barramundi selective breeding program. It also provides an example of what considerations need to be made for the genetic management of mass spawning and/or cannibalistic species.

Coastal geomorphic conditions and styles of storm surge washover deposits from Southern Thailand

The characteristics of tropical storm washover deposits laid down during the years 2007 to 2011 along the southern peninsular coast of the Gulf of Thailand (GOT) were described in relation to their different geomorphic conditions, including perched fan, washover terrace and sheetwash lineations preserved behind the beach zone within 100m of the shoreline. As a result, washover terrace and sheetwash lineations were found where the beach configuration was uniform and promoted an unconfined flow. Non-uniform beach configurations that promoted a confined flow resulted in a perched fan deposit. Washover sediments were differentiated into two types based on sedimentary characteristics, including (i) a thick-bedded sand of multiple reverse grading layers and (ii) a medium-bedded sand of multiple normal grading layers. In the case of thick-bedded washover deposits, the internal sedimentary structures were characterized by the presence of sub-horizontal bedding, reverse grading, lamination, foreset bedding and wavy bedding, whereas, horizontal bedding, normal grading, and dunes were the dominant structures in the medium-bedded washover sand. Rip-up clasts were rare and recognized only in the washover deposits in the bottom unit, which reflects the condition when a mud supply was available. All washover successions were found in the landward inclined-bedding with a basal sharp contact. A high elevated beach ridge associated with a large swale at the backshore proved suitable for a thick-bedded washover type, whereas a small beach ridge with uniformly flat backshore topography promoted a medium-bedded washover sediment.

Sedimentology of seismo-turbidites off the Cascadia and northern California active tectonic continental margins, northwest Pacific Ocean

Abstract Holocene turbidites from turbidite channel systems along the active tectonic continental margins of the Cascadia subduction zone (offshore Vancouver Island to Mendocino Triple Junction) and the northern San Andreas Transform Fault (the Triple Junction to San Francisco Bay), have been analyzed for sedimentologic features related to their seismic origin. Centimeter thick silt/sand beds (turbidite base) capped by mud layers (turbidite tail) and interbedded with hemipelagic silty clay intervals with high biogenic content have been characterized by visual core descriptions, grain-size analysis, X-ray radiographs and physical properties. Along the northern California margin in upstream single tributary canyons and channels, most turbidites are uni-pulsed (classic fining up) whereas downstream below multiple tributary canyon and channel confluences, most deposits are stacked turbidites. Because each set of stacked turbidites has no hemipelagic sediment between each turbidite unit and each unit has a distinct mineralogy from a different tributary canyon, we interpret that a stacked turbidite is deposited by several coeval turbidity currents fed by multiple tributary canyons and channels with synchronous triggering from a single San Andreas Fault earthquake. The Cascadia margin is characterized by individual multi-pulsed turbidites that contain multiple coarse-grained sub-units without hemipelagic sediment between pulses. Because the number and character of multiple coarse-grained pulses for each correlative multi-pulsed turbidite is almost always constant both upstream and downstream in different channel systems for 600 km along the margin, we interpret that the earthquake shaking or aftershock signature is usually preserved, for the much stronger Cascadia (≥ 9 Mw) compared to weaker California (≥ 8 Mw) earthquakes, which result in upstream uni-pulsed turbidites and downstream stacked turbidites. Consequently, both the strongest (≥ 9 Mw) great earthquakes and downstream confluences cause multi-pulsed and stacked turbidites that are typical for seismo-turbidites generated by a single great earthquake. Along both margins, earthquake triggering and multi-pulsed or stacked turbidites become an alternative explanation for amalgamated turbidite beds in active tectonic margins and show that multiple grain-size pulses and reverse grading are not unique criteria for hyperpycnites, thalweg levee turbidites, or mini-basin margin turbidites. The analyses of the turbidites along the Cascadia and northern California margins reveal common sedimentologic characteristics of turbidites triggered by great earthquakes that can be used to distinguish seismo-turbidites in other active tectonic margins around the world.

The impact of multiple grading scheme options on student test performance in college economics courses: empirical evidence from Taiwan

This study exploits an experimental opportunity to understand whether or not the introduction of multiple grading scheme options enhance college student learning and test performance in a Principles of Economics course. The econometric findings, based on a sample of students enrolled in the Principles of Economics course at Shih Hsin University, Taiwan in the second semester of the 2008 academic year, offer evidence that the availability of the multiple grading scheme options provides a positive effect on student test performance, particularly among the low midterm score students. The two grading scheme options significantly increase the average score in the final examination by 15.65 points among the poor midterm performance students. The results of this study suggest that the adoption of more flexible ways of assigning grades provides motivations for the poor midterm performance students not to give up and to study harder in the second-half of the course.

Use of anisotropy of magnetic susceptibility (AMS) in the study of tsunami deposits: Application to the 2004 deposits on the eastern coast of Banda Aceh, North Sumatra, Indonesia

We studied emplacement dynamics of the December 26, 2004 tsunami deposits in artificial shallow ponds and in shallow lagoons, along the northern coast of Sumatra in Banda Aceh area. Successive tsunami waves inundated topographic lows, which acted as sediment traps and favored preservation of deposits. Individual waves led to the deposition of fining upwards sedimentary sequences. This multiple normal grading deposit with a thickness ranging from 2 to 80 cm constitutes a site of major interest for the study of the deposits emplaced by a tsunami wave train. The main interest lies in the characteristics of the deposits that can be correlated to the behavior of the waves attested by numerous testimonies. In this setting, we aimed at testing the applicability of the AMS (Anisotropy of Magnetic Susceptibility) technique as a proxy of unconsolidated sediment fabric. The combination of this proxy and traditional sedimentary analysis helped reconstructing the hydrodynamic conditions — particularly the flow direction, prevailing during sedimentation. We applied the AMS technique on eight sections stretching inland from 1.5 km to 2.2 km from the pre-tsunami coastline. Grain-size and AMS data from these deposits provide similar and partially complementary information. Traction dominates in the basal parts of the deposits and occurs mainly for the basal layers of the sequences whereas settling dominates for the upper layers of these sequences. The vertical evolution of the AMS parameters within the deposits is related to the arrival of the successive waves with variations in the traction and decantation processes during deposition. Variations of current strength during sedimentation are related to the wave's momentum and to the progressive infill of topographic depressions. The vertical change of the fifth coarsest percentile vs. the median grain sizes of the deposits suggests strong variations of the energy of the currents, and confirms the evolution of the AMS parameters. In the present study, the fabric of the deposits, which developed exclusively during the uprush phase of the cycle, also allows the reconstruction of flood directions that are both normal and parallel to the shoreline, with variations related to flow dynamics, mean grain size and local topographic control. Due to the absence of backwash in between the waves and low velocity of the final backwash, information about the sedimentation conditions of the tsunami deposits appears to be better preserved in topographic depressions in areas located remote from the seashore. The AMS proxy appears to be a promising tool for further studies of recent- and paleo-tsunami deposits.

THAT’S NEWS TO ME! INFORMATION REVELATION IN PROFESSIONAL CERTIFICATION MARKETS

Using sportscard grading as an example, we employ field experiments to investigate the informational role of professional certifiers. Empirical results suggest three patterns: first, the grading certification provided by the first professional certifier offers new information to inexperienced traders but adds little information to experienced dealers. This implies that the certification may reduce the information asymmetry between informed and uninformed parties. Second, compared with the incumbent, new entrants adopt more precise signals and use finer grading cutoffs to differentiate from the incumbent. Third, our measured differentiated grading cutoffs map consistently into prevailing market prices, suggesting that the market recognizes differences across multiple grading criteria. (JEL D8, C93)

Current measures for the evaluation of acne severity

The overall assessment of acne severity requires consideration of both clinical measures and patient-reported outcomes. This review is focused on recent developments in these interrelated spheres of severity determination. There are multiple current grading scales for active acne and scarring. Furthermore, a number of acne-specific quality-of-life (QoL) measures have been developed. Selection of the most appropriate measures for acne severity is dependent on the intended application. For therapeutic investigations projected for regulatory approval, lesion counting, negotiated and approved global acne scales and complete QoL instruments are advisable. In clinical practice, however, global assessments and indices of QoL instruments may be more practical.

When and how to grade Barrett's columnar metaplasia: The Prague system

Barrett's oesophagus (BO), a well-known precursor for oesophageal adenocarcinoma has been generating a great deal of controversy. The initial step in diagnosing BO requires an accurate endoscopic recognition of the columnar lined oesophagus. A reliable diagnosis of BO depends on its effective endoscopic recognition based on the key anatomic landmarks, followed by histological sampling of the columnar-lined epithelium. Precise localisation of the gastrooesophageal junction is pivotal in the endoscopic diagnosis of BO. Multiple ad-hoc grading systems and terminologies of BO have been proposed based on the Z-line appearance, presence or absence of intestinal metaplasia, and the length of Barrett's segment. However, a universally accepted standardised endoscopic grading system of BO is lacking. The Prague C&M criteria, developed by a subgroup of the International Working Group for the Classification of Oesophagitis, are the first explicit, consensus-driven, clinically relevant criteria for the endoscopic recognition and grading of BO that may be useful in both clinical practice and research trials.

That's News to Me! Information Revelation in Professional Certification Markets

This study uses field experiments to investigate empirically the informational role of professional certifiers. We explore a certification market that has evolved in such a manner that provides a unique opportunity to measure the information provision of a monopolist certifier and that of subsequent entrants. Empirical results suggest that the certification industry plays a dual role: it reduces the information asymmetry between informed and uninformed parties and generates new information to all market players. Interestingly, the second role isn't conspicuous until the certification market becomes competitive, as the monopolist certifier credibly distinguishes lemons from non-lemons for the uninformed party, but adds little information to experienced agents. On the contrary, new entrants adopt more precise signals and use finer grading cutoffs to differentiate from the incumbent. Our measured differentiated grading cutoffs map consistently into prevailing market prices, suggesting that the market recognizes differences across multiple grading criteria.

Multicenter, Prospective, Double-blind, Randomized Trial of Laparoscopic Nissen vs Anterior 90º Partial Fundoplication

Laparoscopic anterior 90 degrees partial fundoplication for gastroesophageal reflux is associated with a lower incidence of postoperative dysphagia and other adverse effects compared with laparoscopic Nissen fundoplication. A multicenter, prospective, double-blind, randomized controlled trial. Nine university teaching hospitals in 6 major cities in Australia and New Zealand. One hundred twelve patients with proven gastroesophageal reflux disease presenting for laparoscopic fundoplication were randomized to undergo either a Nissen (52 patients) or an anterior 90 degrees partial procedure (60 patients). Patients with esophageal motility disorders, patients requiring a concurrent abdominal procedure, and patients who had undergone previous antireflux surgery were excluded from this study. Laparoscopic Nissen fundoplication with division of the short gastric vessels or laparoscopic anterior 90 degrees partial fundoplication. Independent assessment of dysphagia, heartburn, and overall satisfaction 1, 3, and 6 months after surgery using multiple clinical grading systems. Objective measurement of esophageal manometric parameters, esophageal acid exposure, and endoscopic assessment. Postoperative dysphagia, and wind-related adverse effects were less common after a laparoscopic anterior 90 degrees partial fundoplication. Relief of heartburn was better following laparoscopic Nissen fundoplication. Overall satisfaction was better after anterior 90 degrees partial fundoplication. Lower esophageal sphincter pressure, acid exposure, and endoscopy findings were similar for both procedures. At the 6-month follow-up, laparoscopic anterior 90 degrees culine partial fundoplication is followed by fewer adverse effects than laparoscopic Nissen fundoplication with full fundal mobilization, and it achieves a higher rate of satisfaction with the overall outcome. However, this is offset to some extent by a greater likelihood of recurrent gastroesophageal reflux symptoms.

The 26.5 ka Oruanui eruption, New Zealand: an introduction and overview

The 26.5ka Oruanui eruption, from Taupo volcano in the central North Island of New Zealand, is the largest known ‘wet’ eruption, generating 430km3 of fall deposits, 320km3 of pyroclastic density–current (PDC) deposits (mostly ignimbrite) and ∼420km3 of primary intracaldera material, equivalent to ∼530km3 of magma. Erupted magma is >99% rhyolite and <1% relatively mafic compositions (52.3–63.3% SiO2). The latter vary in abundance at different stratigraphic levels from 0.1 to 4wt%, defining three ‘spikes’ that are used to correlate fall and coeval PDC activity. The eruption is divided into 10 phases on the basis of nine mappable fall units and a tenth, poorly preserved but volumetrically dominant fall unit. Fall units 1–9 individually range from 0.8 to 85km3 and unit 10, by subtraction, is 265km3; all fall deposits are of wide (plinian) to extremely wide dispersal. Fall deposits show a wide range of depositional states, from dry to water saturated, reflecting varied pyroclast:water ratios. Multiple bedding and normal grading in the fall deposits show the first third of the eruption was very spasmodic; short-lived but intense bursts of activity were separated by time breaks from zero up to several weeks to months. PDC activity occurred throughout the eruption. Both dilute and concentrated currents are inferred to have been present from deposit characteristics, with the latter being volumetrically dominant (>90%). PDC deposits range from mm- to cm-thick ultra-thin veneers enclosed within fall material to >200m-thick ignimbrite in proximal areas. The farthest travelled (∼90km), most energetic PDCs (velocities >100ms−1) occurred during phase 8, but the most voluminous PDC deposits were emplaced during phase 10. Grain size variations in the PDC deposits are complex, with changes seen vertically in thick, proximal accumulations being greater than those seen laterally from near-source to most-distal deposits. Modern Lake Taupo partly infills the caldera generated during this eruption; a ∼140km2 structural collapse area is concealed beneath the lake, while the lake outline reflects coeval peripheral and volcano–tectonic collapse. Early eruption phases saw shifting vent positions; development of the caldera to its maximum extent (indicated by lithic lag breccias) occurred during phase 10. The Oruanui eruption shows many unusual features; its episodic nature, wide range of depositional conditions in fall deposits of very wide dispersal, and complex interplay of fall and PDC activity.

GRADING, IMAGE ANALYSIS, AND STEREOPSIS OF DIGITALLY COMPRESSED FUNDUS IMAGES

To investigate the effects of image digitization and compression on the ability to identify and quantify features in color fundus photographs. Color fundus photographs were digitized as tagged image file format (TIFF) and high-compression (80:1) and low-compression (30:1) joint photographic experts group (JPEG) images. Rerendered images were subjected to standard grading protocols developed for a clinical trial, and digitized images were subjected to image analysis software for drusen identification and quantitation. Re-created stereoscopic images were compared subjectively with originals. Original, TIFF, and low-compression (30:1) JPEG images were virtually indistinguishable when subjected to close scrutiny with magnification. The overall quality of high-compression (80:1) JPEG images and images digitized at 500 dots per inch was markedly reduced. Protocol grading of original and digitized images was highly concordant within the repeatability of multiple grading of original images. The area subtended by drusen differed by less than 1.0% for all uncompressed and compressed image pairs quantified. Stereoscopic information was accurately preserved when compared with originals for TIFF and low-compression JPEG images. Fundus images can be digitized and stored with significant compression while preserving stereopsis and image quality suitable for quantitative image analysis and semiquantitative grading. Low-compression (30:1) JPEG images may be suitable for archiving and telemedical applications.

Extramedullary plasmacytoma of the head and neck region: clinicopathological correlation in 25 cases

Extramedullary plasmacytomas (EMP) of head and neck are rare tumours. Between 1972 and 1993, 25 cases of EMP of head and neck were seen at our institute. The clinical and pathological features and response to treatment are presented. At initial presentation, 23 (92%) patients presented with disease confined to a single extramedullary site only and two patients had in addition clinical involvement of cervical lymph nodes. All except these two patients received radiotherapy to the primary site only as initial treatment. Initial primary control of local disease was obtained in 16 of 24 (67%) patients treated with radical intent. With salvage treatment of further radiotherapy and/or chemotherapy, local disease control was achieved in 21 of 24 (88%) patients. One patient was treated with palliative intent. Conversion to multiple myeloma was seen in two patients (8%). Pathologically, the tumours were classified into low, intermediate and high grade, which correlated closely with outcome. This classification has been used for the first time in extramedullary plasmacytomas and is based on the multiple myeloma grading criteria devised by Bartl et al (1987). Fifteen of eighteen (83%) low-grade tumours and only one of six (17%) intermediate- and high-grade tumours were locally controlled after primary radiotherapy. This is statistically significant for local control (P= 0.0019) but not for overall survival (P= 0.12). The median survival and 5-year overall survival is 68 months and 58.9% respectively. We recommend consideration of adjuvant chemotherapy in patients with higher grade disease.

Transport and emplacement mechanisms of mass-flow deposits on Monte Vulture volcano, Basilicata, southern Italy

Abstract The Lahar Facies of Mt Vulture, which forms a broad apron around the base of the cone, is composed predominantly of mass-flow deposits. There is a spectrum of lithological types ranging from monolithologic units which may be of a primary pyroclastic flow origin and are composed entirely of juvenile material, to polylithologic deposits, containing a range of clast types, interpreted to be cold debris-flow deposits. Some debrisflow deposits show evidence of being hot on emplacement. Debris-flow deposits are interbedded with lapilli-fall layers and lava flows suggesting formation contemporaneous with eruptive activity. Some debris-flow deposits travelled no more than 3 km from their source. Many flows were apparently non-erosive, although there is one example where a debris-flow eroded clasts from the top of a lava flow. The presence of fractured ‘jigsaw’ blocks and large fragile blocks of pyroclastic material rules out turbulent flow and high shear for much of the transport prior to emplacement. Multiple grading and abundant development of reverse grading with large lava blocks rafted on, or protruding through, the upper surface of flow units implies that the lahars were high-concentration, high-strength flows in which differential shearing produced discontinuous multiple grading. Locally, individual debris-flow deposits have convex upper surface profiles with internal grading paralleling the surface, strongly supporting a conclusion that these debris-flow deposits were emplaced en masse.

The emplacement of intermediate volume ignimbrites: A case study from Roccamonfina Volcano, Southern Italy

A model is presented for the emplacement of intermediate volume ignimbrites based on a study of two ∼6 km3 volume ignimbrites on Roccamonfina Volcano, Italy. The model considers that the flows were slow moving, and quickly deflated from turbulent to non-turbulent conditions. Yield strength and density increased whereas fluidisation decreased with time and runout of the pyroclastic flows. In proximal locations, on the caldera rim, heterogeneous exposures including discontinuous lithic breccias, stratified and cross-stratified units interbedded with massive ignimbrite suggest deposition from turbulent flows. In medial locations thick, massive ignimbrite occurs associated with three types of co-ignimbrite lithic breccia which we interpret as being emplaced by non-turbulent flows. Multiple grading of different breccia/lithic concentration types within single flow units indicates that internal shear occurred producing overriding or overlapping of the rear of the flow onto the slower-moving front part. This overriding of different parts of non-turbulent pyroclastic flows could be caused by at least two different mechanisms: (1) changes in flow regime, such as hydraulic jumps that may occur at breaks in slope; and (2) periods of increased discharge rate, possibly associated with caldera collapse, producing fresh pulses of lithic-rich material that sheared onto the slower-moving part of the flow in front.

Calculation of valve damping circuit losses in 12-pulse HVDC convertors

An analytical method is presented for the calculation of valve damping circuit losses of a 12-pulse HVDC convertor, taking the effects of inductive coupling into account. The extra commutation notches introduced to the valve voltage waveform are expressed in terms of a notch factor, and a general equation for the valve damping circuit loss is derived. The equation is divided into two parts so that the effects of valve stray capacitance and multiple valve grading circuits can be accommodated in a logical manner. An additional component of loss arising from the thyristor stored change phenomenon is also discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Clinical effects of diaper types on the skin of normal infants and infants with atopic dermatitis

Cloth diapers, cellulose core diapers (conventional disposable diapers), and cellulose core diapers containing absorbent gelling material were examined for their effects on diaper rash and skin microbiology of normal infants and infants with atopic dermatitis in a 26-week double-blind clinical trial. Infants with atopic dermatitis wearing the diapers containing absorbent gelling material had significantly lower diaper rash grades than infants with atopic dermatitis wearing cloth diapers at five of eight grading visits. Infants with atopic dermatitis wearing conventional cellulose core diapers had statistically less rash at one of eight visits. There was no statistically significant difference between diaper types at three of the eight visits. At no time did the cloth group have less diaper rash than the conventional cellulose or absorbent gelling material disposable diaper group. A statistical correlation between the severity of general atopic dermatitis outside the diaper area and the diaper rash condition under the diaper occurred only in the atopic dermatitis group wearing cloth diapers. Isolation of microorganisms from the intact, uninvolved skin surface both inside and outside the diaper showed no biologically significant changes in the presence or numbers of selected skin organisms. Repeated isolation, at multiple grading visits of Staphylococcus aureus from uncompromised skin inside the diaper area was infrequent but correlated with the diagnosis of atopic dermatitis when observed.